Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘C’
Glossary of technical terms for the use of metallurgical engineers
Terms starting with alphabet ‘C’
C4 grass – It refers to a type of grass, such as switchgrass (Panicum virgatum L.), which utilizes a specific photo-synthetic pathway which improves its efficiency in capturing carbon di-oxide and converting it into biomass, making it valuable for sustainable bioenergy production.
Cable – It is a line made of rope, chain or wire which has different functions as per the application it is used for. It can either tie together two points or simply connect them, as in electricity conveyance or data transmission, and can be load bearing or non-load bearing.
Cable accessories – These are the supporting hardware, fittings, and components used to install, connect, terminate, join, protect, and manage electrical or communication cables.
Cable assembly drawing – It depicts an electrical cable assembly of defined length and establishes item identification for that assembly. It is prepared to describe power, signal, radio frequency, audio and general-purpose electrical cable assemblies including both single-run and branched cables. It includes (i) dimensions and tolerances for overall length and breakout locations, (ii) identification of parts, bulk materials, and processes required for fabrication of the cable assembly, (iii) preparation of the cable ends, (iv) orientation and offset of connectors, (v) maximum diameter of cable, (v) minimum bend radii for wiring within the assembly, (vi) detail views of moulded areas, (vii) conductor lay patterns, (viii) identification band or other marking requirements, (viii) a wiring list, wiring diagram, or schematic diagram, (ix) finish, special assembly, and/or storage instructions and (x) test requirements.
Cable attenuation – It is the gradual loss of signal strength, power, or amplitude as a signal travels through a coaxial cable or other transmission medium.
Cable design – It is the systematic process of creating a functional, safe, and durable cable by defining system requirements, choosing appropriate materials, and optimizing electrical, mechanical, and environmental performance.
Cable-driven mechanism – It is a system which utilizes cables to transmit motion, allowing for flexible movement and actuation. It uses flexible cables and winches instead of heavy rigid links to transmit motion, control position, and actuate loads.
Cable installation – It is the systematic process of planning, routing, laying, securing, and testing electrical, control, or telecommunication cables to ensure safe and efficient power or data transmission.
Cable jacket – It is the outermost protective layer of an electrical or fibre optic cable. It serves as the first line of defense against physical damage, moisture, chemicals, and extreme temperatures.
Cable jointing – Cable joint is a device used to join two or more cables together for extension of lengths or to branch. These joints are made to perform at the same voltage class and ratings of the intended cables and are able to withstand the normal and emergency loading conditions. Selection of the proper cable accessories, proper jointing techniques, skill and workmanship is important. The quality of joint is to be such that it does not add any resistance to the circuit. All underground cable joints are to be mechanically and electrically sound and it is protected against moisture and mechanical damage. The joint is to be further resistant to corrosion and chemical effects. The basic types of cable joints are (i) straight through joint which is used to connect two cables lengths together (simple straight through joints which are for jointing same type of cables and transition straight through joints which are for jointing two different type cables), and (ii) tee joint / branch joint which is normally used for jointing a service cable to the main distribution cable in distribution network.
Cable jointing accessories – Several types of jointing accessories are mainly used for jointing all types of low voltage and medium voltage power cables. Every jointing kit is provided with an instruction manual supplied by the manufacturer. Joints are to be made as per the guidelines given in the instruction manual. Cable jointing has (i) heat shrinkable jointing kit (preferred), (ii) cold shrinkable jointing kit, (iii tapex tape type jointing kit, (iv) push on type jointing kit, and (v) cast resin jointing kit.
Cable layout – It is the strategic planning, arrangement, and routing of electrical or data cables within a facility, building, or electromechanical product.
Cable route – It refers to the designated path which cables, such as instrument and electrical cables, follow within a facility, frequently utilizing equipment like cable trays or ladders to ensure proper organization and protection.
Cable routing – It is the planned design and physical installation of pathways for electrical, data, or instrument cables to run safely from their source to their destination.
Cable sheathing – It is the outermost protective layer of an electrical or fibre optic cable which shields the internal components from physical damage, moisture, and environmental hazards. It is a protective layer, typically made from materials like polyvinyl chloride (PVC) or cross-linked poly-ethylenes, which encases electrical cables to improve durability and resistance to environmental factors.
Cable shield – It is a protective, conductive layer surrounding a cable’s internal conductors which blocks electro-magnetic and radio frequency interference.
Cable-stayed bridge – It is a structural engineering system where the bridge deck is supported directly by diagonal tension cables attached to one or more vertical towers or pylons.
Cable structure – It is a type of tension structure which bears loading through tensile forces, frequently incorporating elements such as cables and membranes.
Cable tension – It is the pulling force transmitted axially along the length of a flexible cable, rope, or wire when it is stretched or loaded by external forces.
Cable tray – It is a rigid structural system used to securely support, organize, and route bundles of insulated electrical, control, and communication cables. Unlike closed conduits or pipes, cable trays feature open or ventilated designs. This structural openness provides several critical engineering advantages such as heat dissipation, easy maintenance, and scalability.
Cable tunnel – It is a fully enclosed underground passageway designed to house, organize, and protect high-capacity electrical power and communication cables.
Cache – It is a high-speed hardware or software layer which stores a temporary subset of data so that the future requests for that data are served faster.
Cache storage – It is a high-speed data layer which temporarily stores a subset of frequently used data so future requests are served faster than accessing the primary storage location.
Cache tag – It is the directory entry that holds the address identifying where a cache line was copied from main memory. It is essential for the cache to know the origin of the information stored in each cache line.
CAD / CAM modelling techniques – These refer to the use of computer software to digitally create, modify, analyze (computer-aided design, CAD), and translate designs into machine instructions for manufacturing (computer-aided manufacturing, CAM).
CAD databases and automated inspection equipment techniques – These techniques refer to the digital integration of computer-aided design (CAD) data models with automated quality control systems, such as coordinate measuring machines (CMMs) and optical scanners, to streamline part measurement, verification, and manufacturing tolerance validation.
CAD forging and tooling database – It is the process of using computer-aided design (CAD) to build 3D models and structural specifications for metal forging dies, moulds, and manufacturing tools, while organizing their geometric data, material properties, and operational parameters inside a centralized engineering database.
Cadmium – It is a soft, malleable, ductile, silvery white di-valent metal found in zinc ores, and to a much lesser extent, in the cadmium mineral greenockite. It is similar in several respects to zinc but forms complex compounds. Unlike majority of other metals, cadmium is resistant to corrosion and is used as a protective plate on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable, however, in its powdered form it can burn and release toxic fumes.
Cadmium battery – It is technically known as a nickel-cadmium battery or NiCd battery. It is a type of rechargeable electro-chemical cell that uses nickel oxide hydroxide as the positive electrode and metallic cadmium as the negative electrode.
Cadmium plating – It is a process in which a thin layer of cadmium, a silvery-white metal, is deposited onto the surface of another metal, typically steel, iron, or aluminum. This process is normally achieved through electroplating, where an electric current is used to facilitate the cadmium ions in a solution to deposit onto the substrate. Cadmium plating is valued for its ability to provide corrosion resistance, lubricity, and solderability to the coated metal. It is frequently used in applications needing durability and protection from harsh environments, such as in aerospace, military, and automotive industries. Electro-deposits of cadmium are used to protect steel and cast iron against corrosion. Since cadmium is anodic to iron, the underlying ferrous metal is protected at the expense of the cadmium plate even if the cadmium becomes scratched or nicked, exposing the substrate. Cadmium is normally applied as a thin coating (less than 25 micro-meters thick) intended to withstand atmospheric corrosion. It is seldom used as an undercoating for other metals, and its resistance to corrosion by most chemicals is low.
Cadmium selenide – It is a crystalline inorganic semi-conductor made of cadmium (Cd) and selenium (Se), with a direct bandgap of 1.74 electron volts at room temperature.
Cadmium telluride thin film – It is a poly-crystalline semi-conductor layer, typically a few micrometers thick, composed of cadmium and tellurium, renowned for its near-ideal direct bandgap of around 1.45 electron volts to 1.5 electron volts (eV) and a very high optical absorption coefficient.
Cadmium telluride solar cell – It is a thin-film photo-voltaic device which uses a p-type cadmium telluride (CdTe) absorber layer and an n-type cadmium sulphide (CdS) window layer to convert sunlight into electricity.
CAD programmes – These are specialized software tools used by engineers to create, modify, analyze, and document precise two-dimensional (2D) drawings and three-dimensional (3D) virtual models of physical components and systems.
Caesium-137 (Cs-137) – It is a radioactive isotope of caesium which is formed as a fission product by nuclear fission. In small amounts it can be used to calibrate radiation-detection equipment. Caesium shares similar chemical properties to other Group 1 elements including sodium and potassium. If ingested, Cs-137 is distributed fairly uniformly throughout the body’s soft tissue, resulting in exposure of those tissues which can be treated with Prussian Blue (Ferric Hexacyanoferrate). The magnitude of the health risk depends on exposure conditions. These include factors such as strength of source, length of exposure, distance from the source, and whether there was shielding between the tissue and the source (such as metal plating).
CAFE model – CAFE model stands for a cellular automata-finite element model. It is a multi-scale simulation technique used to predict micro-structure formation and grain evolution during metal processing.
Cage – It is a part of the valve trim which surrounds the closure member and can provide flow characterization and / or a seating surface. It also provides stability, guiding, balance, and alignment, and facilitates assembly of other parts of the valve trim. The walls of the cage contain openings which normally determine the flow characteristic of the valve. In a bearing, it is a device which partly surrounds the rolling elements and travels with them, the main purpose of which is to space the rolling elements in proper relation to each other.
Cage induction motor – It is a type of three-phase induction motor which is widely used for constant-speed drives because of its low cost and high reliability, and it can also serve as a variable-speed drive with the aid of electronic control techniques.
Cake – It is a copper or copper alloy casting, rectangular in cross section, used for rolling into sheet or strip. It is also a coalesced mass of unpressed metal powder. It is also the accumulated layer of solid or semi-solid particles left on a filter medium after a liquid-solid suspension passes through it.
Cake filtration – It is a solid-liquid separation process where suspended particles are retained on the surface of a filter medium, building up a porous layer of solids known as a filter cake.
Cake washing – It is a solid-liquid separation step where a clean liquid is passed through a formed filter cake to flush out residual impurities, contaminants, or mother liquor.
Calandria – It is a cylindrical vessel or heating unit containing a bundle of tubes, used mainly as a heat exchanger, an evaporator core, or the main reactor vessel in specific nuclear designs.
Calandria tube – It is a thin-walled, cylindrical structural component used in pressurized heavy-water nuclear reactors to separate the hot inner pressure tubes from the cooler heavy-water moderator.
Calcareous coating or deposit – It is a layer consisting of a mixture of calcium carbonate and magnesium hydroxide deposited on surfaces being cathodically protected against corrosion, because of the increased pH adjacent to the protected surface.
Calcination – It consists of heating ores, concentrates, precipitates, or residues to decompose carbonates, hydrates, or other compounds. The calcination process needs heating a material to a high temperature with the intent of chemical dissociation (chemical separation). The process is used for the calcination of limestone, dolomite, and magnesite.
Calcination step – It is the process of heating carbonate rocks, such as limestone or dolostone, to high temperatures (typically between 600 deg C and 900 deg C) to decompose them into oxides, producing quicklime (CaO) and carbon di-oxide (CO2) through endothermic reactions.
Calcine – It is a refractory material, frequently fireclay, which has been heated to eliminate volatile constituents and to produce desired physical changes.
Calcined clay – It is a thermally activated alumino-silicate material used as a supplementary cementitious material to replace a portion of clinker in low-carbon cement.
Calcining of refractory material – It is the heat treatment to which raw refractory materials are subjected, preparatory to further processing or use, for the purpose of eliminating volatile chemically combined constituents and producing volume changes.
Calcining zone – In calcining zone of the kiln, fuel is burned in preheated air from the cooling zone and (depending on the design) in additional ‘combustion’ air added with the fuel. In this zone, temperatures of higher than 900 deg C are produced. From 800 deg C to 900 deg C, the surface of the limestone starts to decompose. At temperatures above the decomposition temperature of limestone, i.e. 900 deg C, decomposition takes place below the surface of the limestone pieces. At a temperature of 900 deg C, these pieces leave the calcining zone and are sometimes found as residual limestone which is still trapped inside. If the pieces which are decomposed fully and still reside in the calcining zone, sintering occurs.
Calcio-thermic reduction – It is a high-temperature chemical process which uses metallic calcium as a reducing agent to extract pure metals from their oxides, fluorides, or chlorides.
Calcium (Ca) – It is a metallic chemical element of the alkaline-earth group having atomic number 20 and atomic weight 40.08. Calcium additions are made during steel making for refining, deoxidation, desulphurization and for the control of shape, size and distribution of oxide and sulphide inclusions. Calcium is not used as alloying element since its solubility in steel is very low.
Calcium aluminate – It refers to a group of inorganic compounds formed by heating calcium oxide and aluminum oxide together, mainly used as high-performance specialty binders. It is made by sintering or fusing limestone and bauxite at high temperatures. Its mineral phases include mono-calcium aluminate (CA), mono-calcium di-aluminate (CA2), and tri-calcium aluminate (C3A).
Calcium aluminate cement – It is a hydraulic binder made by fusing or sintering bauxite and limestone. Unlike Portland cement, its main part is calcium aluminate. It is used for very high heat, fast hardening, and strong defense against chemicals and sulphates.
Calcium aluminate (CA) flux – It is a material used in secondary metallurgy, to remove impurities from steel. It is essentially a fluxing agent which helps to create a slag (liquid waste product) which absorbs impurities, aiding in the purification process.
Calcium aluminum silicon – It very frequently refers to a composite alloy or an alumino-silicate mineral compound containing calcium, aluminum, and silicon. It is used either as a powerful deoxidizer and desulphurizer in steelmaking.
Calcium aluminum-silicate – It is also called calcium alumino-silicate. It is an inorganic chemical compound made of calcium, aluminum, silicon, and oxygen. It appears as a fine, white, odourless powder which does not dissolve in water. It occurs naturally in minerals like anorthite or is made for industrial uses.
Calcium-based sorbent – It is a solid material, typically derived from natural limestone or industrial waste containing calcium oxide, carbonate, or hydroxide. It is to capture acidic gases like carbon di-oxide (CO2) and sulphur di-oxide (SO2) through reversible chemical reactions.
Calcium binder – It is a calcium-rich material, such as ordinary Portland cement or lime, which chemically reacts with water to bind aggregates and harden construction materials.
Calcium boride – It is normally known as calcium hexaboride (CaB6), is an inorganic chemical compound made of calcium and boron. It appears as a dark, lustrous powder that is chemically stable, highly hard, and electrically conductive. It is an important material because of its high electrical conductivity, hardness, chemical stability, and melting point. It is a black, lustrous, chemically inert powder with a low density. It has the cubic structure typical for metal hexaborides, with octahedral units of 6 boron atoms combined with calcium atoms. Calcium boride and lanthanum-doped calcium boride both show weak ferro-magnetic properties, which is a remarkable fact since calcium and oron are neither magnetic, nor have inner 3d or 4f electronic shells, which are normally needed for ferro-magnetism.
Calcium carbide – It is also known as calcium acetylide, is a chemical compound with the chemical formula of CaC2. Its main use is in the production of acetylene. In steel industry, it is used for desulphurization and de-oxidation.
Calcium carbonate (CaCO3) – It is a widely used industrial mineral (limestone) compound and chemical raw material utilized as a structural filler, pH stabilizer, slag former, and main ingredient in cement and concrete manufacturing.
Calcium chloride – It is an inorganic ionic salt (CaCl2) used as a powerful drying, heat-releasing, and freezing-point-lowering agent. It is a white, hygroscopic solid. This means it absorbs moisture quickly from the air and releases heat when it dissolves. Engineers rely on these unique physical and chemical traits for construction, road maintenance, and resource extraction.
Calcium di-silicide (CaSi2) – It is an inorganic compound, a silicide of calcium. It is a whitish or dark grey to black solid matter with melting point 1,033 deg C. It is insoluble in water, but can decompose when subjected to moisture, evolving hydrogen and producing calcium hydroxide. It is used both in the form of powder and lumps in iron and steel industry as a powerful deoxidizer and desulphurizer, owing to the high affinity of calcium, for oxygen, sulphur and other elements.
Calcium ferrite – Its chemical formula is (CaFe4O7). It is also known as calcium bi-ferrite or hemicalcic ferrite. It, is a synthetic, iron-rich binary metal oxide compound composed of calcium, iron, and oxygen. In oxide notation, it is represented as CaO⋅2Fe2O3. It is one of several phases which form within the calcium oxide-iron(III) oxide (CaO-Fe2O3) ternary system. It mainly exists as an important intermediate or bonding phase in industrial metallurgy and advanced material sciences.
Calcium fluoride – Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white solid that is practically insoluble in water. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities. Metallurgical grade fluorites with 60 % to 85 % calcium fluoride (CaF2) content are used to reduce slag surface pressure in steel production, to reduce melting temperature and slag viscosity.
Calcium fluoride coating – This type of electrode coating provides shielding gas to protect the arc, adjusts the basicity of the slag, and provides fluidity and solubility of the metal oxides.
Calcium formate – It is an organic calcium salt with the chemical formula [Ca(HCOO)2] used in construction as an accelerator to speed up cement and mortar hardening times. It is odourless, free-flowing white crystalline powder. It is readily soluble in water, making it easy to mix into aqueous and dry-mortar systems. It is stable up to its high decomposition temperature above 300 deg C.
Calcium hydroxide – It is also called slaked lime, or hydrated lime. It is a strong alkaline inorganic compound with the chemical formula Ca(OH)2. It is soft, white powder or colourless crystals. It is highly alkaline (aqueous solution has pH value of around 12.5. It is formed through an exothermic reaction by mixing quicklime (CaO) with water (slaking).
Calcium looping (CaL) process. – It is a carbon di-oxide (CO2) capture technology which utilizes quicklime (CaO)-based sorbents to facilitate reversible reactions (carbonation and calcination) for separating a carbon di-oxide from emissions in several carbon-intensive sectors. This method is noted for its potential benefits, including minimal impact on power plant efficiency, although it faces challenges such as sorbent deactivation during cyclic operation.
Calcium magnesium aluminate (CMA) flux – It is a type of flux used in several industrial processes, including steelmaking, to improve the quality and efficiency of molten metal. It is a synthetic slag-forming material composed mainly of calcium oxide (CaO), magnesium oxide (MgO), and aluminum oxide (Al2O3). Calcium magnesium aluminate fluxes are known for their ability to rapidly form a homogeneous liquid slag which effectively removes impurities and inclusions from the steel bath, similar to calcium aluminate (CA) fluxes. They also play a crucial role in desulphurization, a process of removing sulphur from molten steel.
Calcium molybdate – it is an inorganic chemical compound with the formula CaMoO4. It appears as a white to yellowish crystalline powder which is nearly insoluble in water. It serves as a key industrial additive in steelmaking, a precursor for molybdenum materials, and a pigment. Commercial calcium molybdate is a crushed product containing 40 % to 50 % molybdenum, 23 % to 25 % lime, 3 % iron maximum and 5 % to 10 % silica, used to add molybdenum to iron and steel produced during steelmaking.
Calcium nitrite – It is an inorganic chemical compound with the formula Ca(NO2 which is widely used as a corrosion inhibitor and set accelerator for reinforced concrete.
Calcium per-oxide – It is an inorganic chemical compound with the formula CaO2 which acts as a solid oxygen-releasing agent. It typically appears as an odourless, white or yellowish powder which is nearly insoluble in water but decomposes slowly in aqueous environments to release oxygen.
Calcium phosphate cement – It is a self-setting material formed by mixing calcium phosphate powders with an aqueous liquid to create a mouldable paste which hardens in situ through a dissolution-precipitation reaction.
Calcium precursors – These precursors refer to compounds such as calcium acetate, calcium citrate, calcium d-gluconate, calcium formate, and calcium l-lactate which are utilized to synthesize calcium oxide (CaO) sorbents, aimed at improving carbon di-oxide (CO2) sorption performance through the development of materials with meso-porous and macro-porous structures.
Calcium silicate cement – It is a hydraulic binding material which sets and hardens through a chemical reaction with water, mainly composed of tri-calcium silicate and di-calcium silicate.
Calcium silicate hydrate – It is a gel-like product formed from the reaction of C3S or C2S with water, characterized by a variable composition which typically contains around twice as much CaO (lime) as SiO2 (silica), and is normally denoted as C-S-H to indicate its non-fixed stoichiometry.
Calcium silicate hydrate (C-S-H) gel – It is the main binding product formed when Portland cement reacts with water, and it accounts for 50 % to 70 % of the volume of hydrated cement paste. A non-stoichiometric, gel-like material with a variable composition (typically represented as (CxSiyHz) produced during cement hydration.
Calcium silicon – It is also called calcium silicide. It is an alloy of calcium, silicon, and iron containing 28 % to 35% calcium, 60 % to 65 % silicon, and 6 % maximum Fe (iron). It is used as a deoxidizer and degasser for steel and cast iron.
Calcium soap – It is a salt formed by the reaction between calcium ions and fatty acids, and is normally used as a thickener in lubricants and greases. It is a key component of several greases and is also used in paints, water-proofing agents, and other applications.
Calcium sulphate – It is an inorganic salt which functions mainly as a setting retarder and structural additive in construction. Its different chemical forms are CaSO4 (anhydrous), CaSO4.1/2H2O (hemi-hydrate), or CaSO4.2H₂O (di-hydrate). It occurs naturally or industrially as anhydrite, bassanite (hemi-hydrate / Plaster of Paris), and gypsum (di-hydrate). It nis sparingly soluble in water; dissolves to cause permanent water hardness.
Calcium sulphate hemi-hydrate – Its chemical formula is CaSO4.1/2H2O. It is normally known as Plaster of Paris. It is an important inorganic mineral binder produced by heating gypsum to about 150° deg C.
Calcium sulphite – It is a white chemical solid with the formula CaSO3 which functions mainly as an intermediate by-product in industrial flue-gas desulphurization systems. It exists as a hemi-hydrate CaSO3.1/2H2O or tetrahydrate (CaSO3.4H₂O). Its melting point is 604 deg C (decomposes / melts under specific thermal bounds). It is slightly soluble in water. It is captured when calcium-based scrubbers remove sulphur di-oxide (SO2) emissions from fossil-fuel power plant exhaust.
Calcium sulphite hemi- hydrate – Its chemical formula is CaSO3.1/2H2O. It is a critical crystalline compound mainly encountered in environmental engineering, specifically during the flue-gas desulphurization (FGD) process in coal-fired power plants. It forms as a major by-product when sulphur di-oxide (SO2) gas is scrubbed from exhaust emissions using calcium-based sorbents like lime or limestone.
Calcium sulpho-aluminate – It is a specialized, eco-friendly hydraulic binder and cement type made by grinding calcium sulpho-aluminate (CSA) clinker (mainly ye’elimite) with gypsum. It forms needle-like crystals of ettringite very quickly upon hydration, achieving high early strength within hours. It acts as a shrinkage-compensating material with very low drying shrinkage compared to standard Portland cement. It offers high resistance to sulphate attack and aggressive environments.
Calcium titanate – Its chemical formula is CaTiO3. It is an inorganic ceramic compound. It adopts an orthorhombic perovskite structure at room temperature, shifting to tetragonal and cubic phases at high temperatures. T is typically produced as a fine, white, water-insoluble crystalline powder through high-temperature solid-state reactions.
Calcium treatment – It is a secondary metallurgical process where calcium or calcium alloys are added to molten steel to modify non-metallic inclusions, improve material cleanliness, and prevent casting blockages.
Calcium wire injection – It is a steelmaking process where a metal tube filled with calcium powder or alloy is fed deep into molten steel. This method prevents calcium from evaporating instantly, allowing it to clean the steel, remove sulphur, and improve metal quality.
Calculated emission – It refers to the quantification of green-house gas emissions, specifically carbon di-oxide (CO2), methane (CH4), and nitrous oxide (N2O), associated with the transportation of biomass, determined using distances travelled and emissions per kilometer for road transport. These calculations consider factors such as loading capacity and the available volume of biomass at different hubs.
Calculated surface temperature – It is the predicted or computed thermal value of a solid boundary where heat transfer occurs via conduction, convection, or radiation.
Calculated temperature – It is the temperature which is derived mathematically from internal energy states, entropy derivatives, or energy distribution parameters like the Boltzmann distribution.
Calculation – It is a mathematical process which combines numerical values, physical dimensions, and units to predict, verify, or document how a physical system behaves under specific loads and conditions.
Calculus – It is the mathematical study of continuous change, used to design, analyze, and optimize dynamic physical systems. The two branches of calculus are differential calculus and integral calculus.
Calculus of variations – It is a branch of mathematical analysis which finds the specific function, curve, or surface which minimizes or maximizes an integral expression. While regular calculus finds the numbers (inputs) that make a function as large or small as possible, the calculus of variations finds entire functions which make a functional (a mapping from a set of functions to real numbers) as large or small as possible.
Calculus operations -These are the fundamental mathematical processes of differentiation and integration used to analyze dynamic rates of change and total accumulation in physical systems. These Calculus operations form the backbone of engineering mathematics by translating physical laws into solvable mathematical models.
Calender – It is a roller mill equipped with three or more internally heated or cooled drums, used to continuously sheet out polymeric compound to wipe it into the interstices of a fabric leaving a small portion of it on the surface of the fabric, or to lay a continuous sheet of compound on a fabric. It is the passing of plastic sheet material between sets of pressure rollers to produce a smooth finish and a desired thickness.
Calgon conditioning – It is a water treatment process which uses sodium hexa-meta-phosphate (Na6P6O18) to soften hard water and prevent scale formation. It works by forming soluble complexes with calcium and magnesium ions, which are responsible for hardness.
Calibrated iron ore – It is the sized iron ore normally in the size range of 10 mm to 30 mm.
Calibration – The process of comparison against a ‘standard’ and making the necessary adjustments is normally called calibration. Detailed records are maintained for each item which is calibrated to ensure ‘traceability’, and that the item meets clearly identified specifications for both accuracy and precision in all its operating parameters. Calibration refers to the process of setting the magnitude of the output (or response) of a measuring instrument to the magnitude of the input property or attribute within specified accuracy and precision. Calibration is also a set of operations which establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding values realized by standards. However, it is to be noted that the result of a calibration permits either the assignment of values of the measurands to the indicators or the determination of corrections with respect to indications. A calibration can also determine other metrological properties, such as the effect of influence quantities. The result of a calibration can be recorded in a document, sometimes called a ‘calibration certificate’ or a ‘calibration report’.
Calibration and switching module – This module is a pre-engineered sub-system which conditions and selects process streams or calibration streams for analysis in analytical instruments. It allows users to switch between multiple samples and introduce calibration fluids to the system, ensuring samples are prepared at the appropriate pressure, temperature, flow, and filtration levels before analysis.
Calibration area – It is a specific physical zone or a defined spatial region set up with reference targets (such as calibration grids, markers, or test signals) used to tune, align, and verify sensors, cameras, or robotic systems.
Calibration chain – It is also called a metrological traceability chain. It is an unbroken, documented sequence of comparisons which links a working measurement instrument all the way back to a primary national or international standard.
Calibration chamber – It is a controlled environment or test apparatus used to accurately test, calibrate, and validate sensors, instruments, or material samples under uniform and stable conditions. It is also a controlled environment designed to achieve a uniform and stable distribution of calibration gas for the accurate calibration of gauge heads, featuring specific geometries and materials to minimize gas outgassing and pressure differentials.
Calibration check – It is a systematic procedure used to verify whether a measuring instrument’s accuracy and performance remain within acceptable limits by comparing its readings against a known reference standard.
Calibration coefficients – These are numerical values used to mathematically transform raw, uncalibrated sensor or instrument outputs into accurate, standardized physical quantities.
Calibration constant – It is a numerical multiplier or fixed value used to convert a raw instrument signal or sensor reading into a true, calibrated physical unit.
Calibration curve – It is a graph or mathematical function which plots an instrument’s measured output against known, true input values to ensure accuracy.
Calibration duty – It is the established requirement or scheduled responsibility to compare and verify an instrument’s measurement accuracy against a known reference standard.
Calibration environment – It refers to the controlled physical and atmospheric conditions, such as specific temperature, humidity, pressure, and clean air, in which measuring instruments are tested and calibrated to minimize errors and ensure high accuracy.
Calibration exercise – It is a systematic procedure which compares a measuring instrument’s output against a higher-accuracy reference standard to verify accuracy, document deviations, and adjust performance.
Calibration experiment – It is a structured test which compares an instrument’s output values against known reference standards to establish a reliable mathematical relationship and measure accuracy.
Calibration factor – It is a numerical multiplier or ratio applied to a measuring device’s raw output to correct systematic errors and align results with a certified reference standard. It fixes consistent bias, sensor drift, or linear deviations in instruments like flow meters, load cells, and sensors.
Calibration function – It is a mathematical formula or curve used to convert a raw hardware signal (like voltage or current) from a sensor into a real-world physical measurement value (like temperature, pressure, or concentration).
Calibration gas – It is a standard gas used for calibrating gas analysis instruments, which can be generated from gas cylinders, diluted with purified air or inert gases, or produced in situ by manipulating solution concentrations to create specific gas mixtures.
Calibration laboratory – It is a facility which performs calibrations, meaning they check and document the accuracy of measuring devices or instruments against known standards. The calibration laboratories are typically accredited and recognized for their expertise in providing calibration services, frequently using international standards like International Organization for Standardization / and International Electrotechnical Commission standard ISO/IEC 17025. They ensure the accuracy of measurement equipment used in several industries, including construction, manufacturing, and scientific research. These laboratories consist of a work space which is provided with test equipment, controlled environment, and trained personnel, and which is established for the purpose of maintaining proper operation and accuracy of measuring and test equipment. Calibration laboratories typically perform several routine calibrations, frequently on a production-line basis.
Calibration, pressure – Pressure calibration is the process of comparing the output reading of a pressure-measuring instrument with that of a reference-standard instrument under the same pressure conditions, frequently needing a leakproof seal for accurate measurements. This process can be performed in situ to minimize production delays and can involve the use of portable reference instruments to achieve precise calibration.
Calibration procedure – It is the systematic process of comparing an instrument’s measurement output against a traceable reference standard of known accuracy to detect, document, and correct any deviations.
Calibration process – It is the documented process of comparing a measuring device’s outputs against a traceable reference standard of known accuracy to detect, record, and correct any deviations.
Calibration set-up – It is the physical arrangement of equipment, reference standards, and connections used to test, compare, and adjust a measuring device to ensure its accuracy.
Calibration standard – It is a certified reference material, physical artifact, or test block with precisely known and documented properties used to verify and adjust the accuracy of analytical instruments and testing equipment.
Calibration system – It is a structured process used to compare a measuring instrument or industrial control system against a known reference standard to detect, quantify, and compensate for measurement errors.
Calibration tank – It is a precision-measured container used to determine volumetric capacity, test fluid meters, or calibrate other measurement instruments by mapping exact liquid levels to known volumes.
Calibration task – It is the process of comparing the output of an instrument or sensor under test against the output of a more accurate standard instrument, across a range of inputs, to ensure measurement accuracy and account for changes in instrument characteristics because of the different environmental factors.
Caliche – It is a hardened layer of soil or sediment cemented together by mineral deposits, very frequently calcium carbonate.
Caliche soil – It is a hardened layer of subsurface soil or sediment cemented together by minerals like calcium carbonate.
California bearing ratio – It is a measure of the strength of the subgrade of a road or other paved area, and of the materials used in its construction. The ratio is measured using a standardized penetration test.
Californium (Cf) – Its atomic number 98. It is a highly radioactive, synthetic actinide metal. Since it does not occur naturally on earth and is incredibly expensive to produce, it is never used as a structural material or alloying agent. Its value lies in its role as a diagnostic tool. Specifically, the isotope Californium-252 acts as an exceptionally potent, portable source of neutrons.
Call for bid – It is a formal request issued by an organization to potential suppliers or contractors to submit proposals or offers for providing goods or services. This process is used to ensure fair competition and transparency in the selection of vendors. It is frequently used interchangeably with terms like ‘invitation to bid’ or ‘tender’.
Call request – It is a specially formatted packet generated by a terminal user to initiate a connection to a network, containing the network addresses of both the source and destination. This packet is sent across the network to establish a switched virtual circuit for the duration of the call.
Calomel electrode (Calomel half-cell) – Calomel electrode is half-cell containing a mercury electrode in contact with a solution of potassium chloride of specified concentration that is saturated with mercurous chloride (calomel). This electrode is widely used as a reference electrode of known potential in electrometric measurement of acidity and alkalinity, corrosion studies, voltammetry, and measurement of the potentials of other electrodes. It is also a secondary reference electrode of the composition: Pt/Hg-Hg2Cl2/KCl solution. For 1 N KCl solution, its potential against a hydrogen electrode at 25 deg C and 0.1 MPa is +0.281 V (volts).
Caloric equation of state – It is a thermodynamic relation which connects a substance’s energy content (such as specific internal energy or specific enthalpy) to its other state variables, normally temperature and specific volume or pressure.
Calorie – It is a unit for measuring a quantity of heat and is the quantity of heat needed to increase the temperature of a gram of water by one deg C. The mean calorie is 1/100 of the heat needed to raise the temperature of 1 gram of water from 0 deg C to 100 deg C at a constant atmospheric pressure. A calorie is 4.184 joules.
Calorific value – It refers to the energy content of a fuel, representing the net heat released by a unit quantity of fuel during combustion in the presence of oxygen. It is a crucial factor impacting the furnace performance and efficiency, with gross and net calorific values being the two main types used to measure this energy content.
Calorimeter – It is the apparatus for determining the calorific value of a fuel.
Calorimetric meter – It is an instrument which measures the mass flow rate of a fluid (liquid or gas) by utilizing the principles of heat transfer. It operates on the physical law that a moving fluid absorbs and carries away heat energy from a heated element at a rate proportional to its mass flow velocity. Since it tracks the actual molecular interaction with heat, it measures mass flow directly without needing additional temperature or pressure compensation.
Calorimetry – It is the measurement of quantity of energy transferred as heat by its effect on the states of interacting bodies, e.g., by the quantity of ice melted or by change in temperature of a body.
Calorizing – It consists of imparting resistance to oxidation to an iron or steel surface by heating in aluminum powder at 800 deg C to 1,000 deg C.
C-alpha carbon – It is also called methynic carbon. It refers to a reactive form of surface carbon defined by an approximate x/y carbon-to-hydrogen ratio of around 1 (resembling a CH methyne group). C-alpha carbon typically forms initially during catalytic processes like the oxidative dehydrogenation of hydrocarbons (e.g., propane on cobalt-nickel/ alumina catalysts. It is relatively reactive and easily oxidized compared to heavier forms of carbon deposits.
Calphad – It means calculation of phase diagrams which is done by computer coupling of phase diagrams and thermo-chemistry. Phase diagrams are a very powerful tool for predicting the state of a system under different conditions. The Calphad approach is based on the fact that a phase diagram is a manifestation of the equilibrium thermodynamic properties of the system. It is hence possible to calculate a phase diagram by modelling the thermodynamic properties of all the phases in a system. By combining the models for several low-order systems it is possible to construct multi-component databases, which can be used to predict the state of multi-component alloys. Obvious applications include the direct calculation of phase diagrams, phase equilibria and thermodynamic properties such as Gibbs-energies, chemical potentials, activities, enthalpies and heat capacities using software such as Thermo-Calc. The Calphad method also forms the basis for simulation of phase transformations using phase-field or diffusion simulation methods and for process simulation. This makes it one of the key tools for ICME (integrated computational materials engineering).
Calx – It is a substance formed from an ore or mineral which has been heated. Calx, especially of a metal, is now understood to be an oxide. The term has been also sometimes used earlier to mean calcium oxide.
Cam – It is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion. It is frequently a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path.
Camber – It is deviation from edge straightness, normally referring to the highest deviation of side edge from a straight line. It is also the tendency of material being sheared from sheet to bend away from the sheet in the same plane. Sometimes the term is used to denote crown in rolls where the centre diameter has been increased to compensate for deflection caused by the rolling pressure. It also denotes the planar deflection of a flat cable or flexible laminate from a straight line of specified length. A flat cable or flexible laminate with camber is similar to the curve of an unbanked race track. In rolled metal, camber is a curve across the plane of the sheet, whether down the middle or along one or both edges. Camber is measured by putting a straight edge next to the sheet. The greatest distance between the straight line and the sheet’s curve is the camber. A cambered sheet might be slightly thinner in the middle than on the edges (concave), thicker in the middle (convex), or thinner on one side (triangular). Camber is also the hook or dogleg near the ends of a coil.
Camber angle – It is the inward or outward tilt of a vehicle’s wheel relative to the vertical axis when viewed from the front or rear. Types of camber angle are zero camber, positive camber, and negative camber.
Camber beam – In building, a camber beam is a piece of steel bent or rolled, with an obtuse angle in the middle. It is normally used in platforms and other occasions where long and strong beams are needed. The camber curve is ideally a parabola but practically a circle segment as even with modern materials and calculations, cambers are imprecise.
Camber change – It is also known as camber gain or loss. It is the change in the vertical tilt angle of a vehicle’s wheels as the suspension moves up and down or as the body rolls during cornering.
Camber line – It is the locus of points marked midway between the upper and lower surfaces of an airfoil section, typically curved, with the maximum height above the chord line denoted as delta.
Camber thrust – It is the lateral force generated perpendicular to the direction of travel when a tilted or cambered tire rolls on a flat surface.
Camber tolerances – Camber is the deviation from edge straightness. Maximum allowable tolerance of this deviation of a side edge from a straight line are defined in the standards.
Cam-clay model – It is a foundational elastoplastic constitutive model used to predict the stress-strain behaviour, volume change, and shear strength of soft, cohesive soils like clays.
Camcorder – It is a device which combines a camera section with an image sensor and lens, a recording section, and a viewfinder, enabling the capture and storage of video in digital format. It converts analog signals into digital bytes for recording, utilizing different storage mediums such as tapes and memory cards.
Cam die – It is a specialized metal-working tool which a mechanical-cam to convert a press’s vertical pressing force into horizontal, angled, or sliding motion.
Cam-driven die – It is a specialized stamping tool used in sheet metal fabrication to perform cutting, piercing, or forming operations at an angle different from the vertical press stroke.
Camera – It is an optical instrument or remote-sensing device consisting of a light-proof enclosure which uses a lens system to refract and focus incoming light onto a light-sensitive medium or sensor to record images as physical or digital data.
Camera coverage – It is the area seen by a set of visual sensors, which is essential for solving the camera placement problem. It involves modeling the coverage to optimize the locations and poses of cameras for maximum efficiency in surveillance systems.
Camera matrix – It is a 3×4 matrix which transforms a scene point expressed in homogeneous coordinates into an image point in homogeneous coordinates, incorporating intrinsic and extrinsic parameters which describe the camera’s characteristics and its position and orientation in the world coordinate system.
Camera view – It refers to the specific visual perspective, angular field, and spatial data captured by an imaging sensor or virtual camera projection in a 3D environment. It is the perspective or visual information captured by cameras, which are used as perception devices to acquire data about the environment.
Cam-less spring coiler – It is an advanced manufacturing device which uses independent servo motors and computer controls instead of traditional mechanical cams to shape wire into precise springs. [1, 2]
Cam-less spring coiling -It is a manufacturing method which uses independent computer-controlled servo motors instead of traditional mechanical cams to shape metal wire into springs.
Cam mechanism – It is a mechanical device which converts rotary (spinning) motion into linear or reciprocating (back-and-forth) motion through direct contact.
Campbell diagram – It is a graph used in mechanical engineering to plot a rotating machine’s natural frequencies against its rotational speed. It helps engineers find critical speeds where resonance might cause dangerous vibrations or equipment failure.
Cam press – It is a mechanical forming press in which one or more of the slides are operated by cams. It is normally a double-action press in which the blank holder slide is operated by cams through which the dwell is obtained.
Cam profile – It is the specific curved edge, surface, or groove of a cam mechanism which physically contacts a follower to convert rotary motion into precise linear or oscillating motion.
Cam shaft – It is a mechanical component which provides actuation for valve motion in synchronization with the pistons and crank-shaft, typically connected through gears, chains, or belts. It can be made from materials like cast iron or forged steel, and frequently undergoes surface treatment to withstand severe contact during operation.
Cam spring – It is an elastic mechanical device used in a cam mechanism to keep a follower firmly pressed against a rotating cam profile.
Can – It is a sheathing of soft metal that encloses a sintered metal billet for the purpose of hot working (hot isostatic pressing, hot extrusion) without undue oxidation.
Canal – It is an artificial or engineered open channel built across the ground surface to convey water under atmospheric pressure.
Canal lining – It is the process of adding an impermeable or protective layer to the bed and sides of a canal. Canal linings are the materials used to reinforce and protect the banks and bottom of canals, ensuring structural integrity and water retention.
Candidate designs – These designs refer to the different design concepts generated by a design team which are evaluated against a project brief to determine their suitability for further development. These designs are assessed based on practical production aspects, costs, and their potential to meet specific criteria outlined in the brief.
Candidate process – It typically refers to either the evaluation of manufacturing / design alternatives during product development or the structured recruitment workflow used to hire engineering talent.
Candle filter in engineering is an enclosed pressure-filtration system which uses vertical, cylindrical, tube-like elements (called candles) to separate solid particles from liquids or gases.
Canning – It is a dished distortion in a flat or nearly flat sheet metal surface, sometimes referred to as oil canning. It also means enclosing a highly reactive metal within a relatively inert material for the purpose of hot working without undue oxidation of the active metal.
Canonically conjugate variables – These are pairs of dynamical properties, such as position and momentum, which mathematically define a system’s phase space and are linked through Hamiltonian mechanics or Fourier duality.
Canonical coordinates – These are a special set of coordinates used to describe the state of a system in phase space. They are normally represented as a set of (q1, …, qn, p1, …, pn), where q’s are generalized coordinates and p’s are their conjugate momenta. These coordinates are chosen such that they satisfy certain fundamental relations, mainly the Poisson bracket relations, which simplify the formulation of Hamilton’s equations of motion.
Canonical equations of motion – These are normally known as Hamilton’s equations. These are a set of first-order differential equations which describe how a physical system changes over time using position and momentum. These equations from Hamiltonian mechanics are used to simplify complex dynamic systems, such as robotics, and electrical circuits.
Canonical expansion – It is the process of representing a real random vector in terms of uncorrelated components, which geometrically corresponds to finding conjugate directions with respect to an associated dispersion ellipsoid. This method results in a canonical form of the ellipsoid equation when using appropriate coordinate axes.
Canonical form – It is a standard, unique way of representing a mathematical, logical, or dynamical system so that equivalent structures look identical.
Canonical map – It is a natural, coordinate-free function which maps a structure to a standard quotient, dual, or invariant space without making arbitrary choices.
Canonical system – It refers to a standard, simplified, or optimized mathematical and structural representation used to model, solve, or integrate complex processes, It is a system of equations which possesses at least one basic variable in all equations, where a basic variable has a unit coefficient in its equation and is absent from all others. This system is essential for obtaining optimal solutions in linear programming and forms the basis for the simplex method.
Canopy – It is an overhead roof-like structure with open or partially enclosed sides designed to provide shelter, shade, or architectural emphasis.
Canopy hood – It is an overhead exhaust receptor designed to capture buoyant contaminants, such as hot air, steam, smoke, fumes, and grease-laden vapours, by utilizing the natural thermal updraft generated by the source.
Canopy structure – Canopy structure design involves calculating overhead loads, wind forces, and support mechanics to safely anchor projections which shelter building entrances, walkways, or open spaces.
Cansolv technology – It is an amine-based chemical absorption and regeneration engineering process designed to capture sulphur di-oxide (SO2) and carbon di-oxide (CO2) from industrial exhaust and flue gas streams.
Cant – Cant of a railway track or camber of a road is also referred to as super-elevation, cross slope or cross fall. It is the rate of change in elevation (height) between the two rails or edges. This is normally higher where the railway or road is curved, raising the outer rail or the outer edge of the road providing a banked turn, hence allowing vehicles to maneuver through the curve at higher speeds than otherwise is possible if the surface is flat or level.
Cantilever – It is a rigid structural element, such as a beam or a plate, anchored at one end to a (normally vertical) support from which it protrudes. This connection can also be perpendicular to a flat, vertical surface such as a wall.
Cantilever beam – It is a rigid structural element fixed securely at one end while the other end remains free and unsupported in space.
Cantilever beam bending test – It is a mechanical evaluation method which measures a material’s or component’s stiffness, flexural response, and deflection by applying a controlled force to the free end of a sample while the opposite end remains rigidly fixed.
Cantilever beam method – It is a technique which represents the radial distribution of thrust and torque force loading on a propeller blade by equivalent loads, enabling the evaluation of stress at the maximum thickness point of the blade section through different stress components.
Cantilever bridge – It is a structure which uses horizontal beams, called cantilevers, which are anchored at only one end and project out over open space to support the main load.
Cantilever roll stands – Cantilever roll stands are compact stands which are used in a wide range of sizes for a variety of applications. These applications include (i) single strand mills in horizontal and vertical arrangement, (ii) in split intermediate trains of two or more strands mills, and as pre-finisher stands in wire rod delivery sections. The advantages of these stands include (i) smaller foundations, (ii) cassettes of the same stand type are interchangeable even between horizontal and vertical stands, (iii) high load bearing strength even with small diameters hence ideally suited for high-speed wire rod blocks, (iv) optimum accessibility, and (v) fast roll and stand changing.
Cantilever spring – This is a type of spring which is fixed only at one end.
Canting angle – It is the tilt or angle at which a component is set relative to a vertical or longitudinal reference line.
Cap – It is a type of pipe fitting which is liquid or gas tight. It is also known as plug and is used to cover the end of a pipe. A cap has a similar function to a plug. For screwed systems the cap is having female threads where a plug is having male threads. Cap is also a layer of clay, or other impermeable material, installed over the top of a closed landfill to prevent entry of rainwater and minimize leachate.
Capabilities and limitations – Capabilities are the abilities or qualities which allow someone or something to do something effectively, while limitations are the constraints or restrictions which prevent someone or something from doing certain things or doing them as well as they can. In essence, capabilities are what a person or system can do, and limitations are what they cannot do, or do poorly.
Capability – It is the proven ability of a system, process, or machine to deliver a specific outcome or produce work within needed specifications.
Capability casting – It is the production-process verification castings, (sometimes called sample casting. It is made to establish what the dimensions really are going to be before going into production.
Capability exchange – It is the dynamic process where connected systems, devices, or peers share, negotiate, and match their functional attributes and resource parameters during a handshake or authentication.
Capability management – It is the systematic approach to identifying, building, and sustaining an organization’s collective ability to deliver specific operational outcomes and handle complex technical challenges. Unlike raw capacity (the volume of work a team can handle), capability defines what an organization can achieve through an integrated mix of people, processes, technology, and information.
Capability maturity model – This model is used to assess the maturity of business process capabilities. It was created to assess the capabilities of software development processes but is now used in a number of other industries as well. Like other maturity models, the this model allows organizations to assess themselves against external benchmarks and provides recommendations for improvement.
Capability maturity model integration – It is a proven process improvement framework which helps engineering and software organizations optimize their product development, boost efficiency, and reduce risks. It provides a clear roadmap for measuring and elevating organizational maturity.
Capability ratio – It measures how well a production process or piece of equipment can produce parts within needed specification limits.
Capacitance – It the ability of a system or component to store electrical energy in the form of an electric charge per unit change in electrical potential. It is defined as the magnitude of charge stored on either plate divided by the applied voltage.
Capacitance calculation – It is the process of finding the ability of a system to store electric charge per unit of potential difference, defined by the formula C = Q / V, where ‘C’ is capacitance in farads (F), ‘Q’ is electric charge in coulombs (C), and ‘V’ is voltage or potential difference in volts.
Capacitance manometer – It is an absolute pressure gauge which measures vacuum or gas pressure by detecting the physical bending of a thin metal or ceramic diaphragm.
Capacitance measurements – These measurements refer to a method for quantifying chemical adsorption and desorption by assessing changes in capacitance, typically achieved through the use of di-electric media positioned between electrodes. This technique is normally used in humidity sensors and different chemical sensors to monitor environmental conditions.
Capacitance per unit area – It is the quantity of electrical capacitance a system or component has divided by its conductive surface area, typically measured in farads per square meter. It measures how efficiently a structure (such as a parallel-plate capacitor or semi-conductor junction) stores electric charge per unit of voltage normalized across its physical cross-section or plate area.
Capacitance sensors – These are devices which detect nearby objects by measuring changes in the electro-static field caused by variations in capacitance, which occur when conductive or non-conductive targets are brought near the sensing surface. They are characterized by their simplicity, high sensitivity, and low power requirements, and are used in applications such as position detection and fluid level monitoring.
Capacitive accelerometers – These are sensors which determine acceleration by measuring the displacement of a proof mass relative to the housing, utilizing two capacitors formed between the mass and plates above and below it. They are particularly advantageous for monitoring large structures because of their stability, sensitivity, and ability to measure across a wide frequency range, although they are sensitive to temperature and humidity variations.
Capacitive coupling – It is the transfer of electrical energy between two circuits or nodes through an electric field, without a direct physical connection.
Capacitive loading – It refers to the condition where an audio driver output stage sees a highly capacitive load when connected via long transmission lines, frequently resulting in stability challenges in the design of the driver.
Capacitive loading condition – It happens when an electrical or electronic circuit output is connected to a load with high capacitance, such as long transmission lines, cables, or gate capacitances, forcing the driving circuit to supply extra charging current.
Capacitive deionization – It is an electro-chemical water treatment technology which removes salt and charged ions from water using an electrical field and porous electrodes.
Capacitive microphones – These are defined as devices which operate based on the principle of capacitance, consisting of two parallel plates, a movable diaphragm and a rigid backplate, which are separated by an air gap. The diaphragm vibrates in response to acoustic pressure, causing variations in the air gap that change the electric capacitance of the microphone.
Capacitive pressure measurement – The principle of capacitive pressure measurement is based on the measurement of the capacitance of a capacitor, which is dependent upon the plate separation. The capacitance of a dual-plate capacitor is determined using the equation C = e. (A/d), where ‘C’ is the capacitance of the dual-plate capacitor, ‘e’ is permittivity, ‘A’ is the area of the capacitor plate, ‘d’ is the plate separation. The principle of capacitive pressure measurement is achieved using a main body with a metallic diaphragm, or one coated with a conductive material, which forms one of the two plates of a dual-plate capacitor. If the diaphragm is deflected under pressure, the plate separation of the capacitor decreases, which results in an increase in its capacitance while the plates’ surface area and permittivity remain constant. In this way, the pressure can be measured with high sensitivity. Hence, capacitive pressure measurement is also suitable for very low-pressure values, even down in the single digit milli-bar range.
Capacitive reactance – It is the opposition which a capacitor presents to the flow of alternating current, which is influenced by the rate of change of voltage across the capacitor and is represented as a negative value in the mathematical complex plane.
Capacitive sensor – It an electronic device which detects or measures objects, touch, or fluid levels by sensing changes in an electrical field (capacitance) without needing physical contact.
Capacitor – It is an electrical component which stores energy in an electric field.
Capacitor bank – It is a collection of multiple individual capacitors connected in series or parallel to store electrical energy and improve power efficiency in electrical systems. – It is a method for controlling voltage in distribution systems, supplying reactive power to offset the reactive power drawn by loads, which reduces the current and voltage drop in feeder circuits.
Capacitor discharge – It is the process by which a capacitor releases its stored electrical energy, essentially emptying the charge which has been stored within it. This happens when a path is created for the charge to flow, frequently through a resistor, and the voltage across the capacitor decreases.
Capacitor discharge stud welding – Capacitor discharge stud welding is a stud arc welding process in which the tip of the stud melts almost instantly when energy stored in capacitors is discharged through it. The three basic modes of capacitor discharge stud welding are initial-gap welding, initial-contact welding, and drawn-arc welding.
Capacitor filter – It is an electronic circuit component connected in parallel with a load to convert pulsating direct current (DC) into a smooth, steady direct current signal by removing unwanted alternating current (AC) ripples.
Capacitor impedance – It is the total opposition that a capacitor offers to the flow of alternating current (AC) in a circuit, measured in ohms.
Capacitor motor – It is a single-phase AC (alternating current) induction motor which uses a capacitor to create a phase difference between its windings, producing the rotating magnetic field needed to start and run.
Capacitor storage – It is the method of holding electrical energy inside an electric field created between two conductive plates.
Capacitor voltage – It is the electrical potential difference which builds up between the two conductive plates of a capacitor as it stores an electrical charge.
Capacity – It is the quantity of flow through a valve, under stated conditions. It is also the normal ability to produce metals in a given time period. This rating includes maintenance requirements, but because such service is scheduled to match the needs of the machinery (not those of the calendar), a plant or smelter can run at more than 100 % of capacity one month and then fall well below rated capacity as maintenance is performed. Engineered capacity is the theoretical volume of a mill or smelter, given its constraints of raw material supply and normal working speed. True capacity is the volume at full utilization, allowing for the maintenance of equipment and reflecting present material constraints. (bottlenecks of supply and distribution can change over time and with it the capacity expands or reduces).
Capacity-building – It is defined as the process of developing and strengthening the skills, instincts, abilities, processes and resources which organizations and communities need to survive, adapt, and thrive in a fast-changing world. An essential ingredient in capacity-building is transformation which is generated and sustained over time from within. Transformation of this kind goes beyond performing tasks to changing mindsets and attitudes.
Capacity constraints – These refer to the limitations on the maximum quantity of resources or output which a facility or system can handle, as outlined in network design and production planning problems, which can include provisions for potential expansions with additional capacity modules.
Capacity control – It is a system or method used to adjust the output of a machine, plant, or process so which it matches real-time demand. It is very frequenty used in engineering systems like air conditioners, refrigerators, chillers, and industrial air compressors. The main goal is to save energy, prevent equipment damage, and keep system performance steady when demand goes down.
Capacity costs – These costs are normally fixed costs. These costs are those costs which are incurred by the organization for providing production, administration, and selling and distribution capabilities in order to perform various functions.
Capacity development – It is the process through which individuals, organizations and societies obtain, strengthen and maintain the capabilities to set and achieve their own development objectives over time. Capacity development is necessary for making a sustainable progress. While frequently equated with training only, the concept of capacity development entails much broader components and considerations, such as (i) fostering a common vision and operating framework (laws, policies, protocols), (ii) building a critical mass of human resources (through targeted recruitment of employees with the right experience and skills, training and other supports), (iii) installing the appropriate infrastructure, such as equipment and supplies to facilitate implementation, (iv) developing or expanding partnerships to maximize the resources and effectiveness of interventions by bringing together the strengths and assets of different stakeholders, (v) improving the knowledge base and ongoing learning through monitoring and evaluation of interventions, and (vi) increasing technical and financial resources.
Capacity dimension – It is also known as the box-counting dimension or box dimension. It is a measure which describes how completely a fractal or subset fills a multi-dimensional space as the scale of measurement changes.
Capacity factor – It is the ratio of the average load carried to the maximum design capacity.
Capacity limit – It is the maximum quantity of a substance, number of people, data rate, or operational output which a system, container, or facility can hold, handle, or process safely.
Capacity limitation – It is a restriction on the maximum quantity of work, data, production, or service which a system, person, or resource can handle.
Capacity market – It is a mechanism designed to ensure sufficient reliable capacity in the electricity system by providing payments which encourage investment in new capacity or the retention of existing capacity. Participants can bid for contracts in auctions held four years and one year ahead of the delivery date, ensuring that contracted capacity is available during peak demand times.
Capacity market design – It is the structured framework and set of rules used by electricity systems to ensure there is always enough power generation and resource availability to meet peak demand. Instead of paying power plants only for the actual electricity they produce, a capacity market pays eligible resources for being built, maintained, and ready to supply power during future periods of system stress.
Capacity mechanism – It is a regulated system which pays power plants, storage facilities, or flexible consumers to stay available for generating or reducing electricity when the power grid faces shortages.
Capacity number – It is the product of the Sommerfeld number and the square of the length-to-diameter ratio of a journal bearing.
Capacity obligation – It is a formal commitment by an energy producer or resource owner to keep a specific amount of power generation or reduction ready to deliver to the electricity grid when requested. Awarded through a capacity auction, it needs providers to supply a set quantity of power during periods of high demand or grid emergencies.
Capacity payment – It is a fee paid to power plant owners for keeping their electricity generation ready, rather than for the actual electricity they produce.
Capacity performance – It measures how well a system, resource, or human produces maximum output or handles workload relative to its established limits and efficiency standards.
Capacity planning – It is the systematic process of determining and matching an organization’s available resources, such as employees, equipment, computing infrastructure, and time, with the work-load needed to meet future project demands. It answers the fundamental question of whether a team or system has the capacity to handle upcoming work without causing bottle-necks, delays, or burn-out.
Capacity price – It is the cost per unit (normally per kilowatt or megawatt) paid to power generators or service providers to keep enough reserve capacity ready for peak demand times.
Capacity ratio – It compares a system’s actual output, load, or demand to its maximum possible or design limit.
Capacity reduction – It is the process of making an industrial plant, system, or resource smaller in output, size, or maximum potential.
Capacity region – It is the set of all possible data transmission rates or spectral efficiencies which multiple users can achieve simultaneously in a shared communication network with reliable data transfer.
Capacity reserve – It is extra supply, power, or space kept in hand to handle emergencies, peak loads, or specific group needs when demand goes up.
Capacity resource – It is the total maximum quantity of work, output, or service which available assets (such as staff, equipment, or facilities) can deliver over a specific period.
Capacity transmission system – System transmission capacity refers to the actual power transmission ability of electrical circuits, which is influenced by the dynamic characteristics of the power system and can be improved through advanced technologies and optimizations in grid structure and control.
Capacity utilization – It measures the percentage of an organization’s maximum potential output which is actually being realized and produced.
Capacity utilization rate – It measures the percentage of an organization’s total potential production output which is actually being realized.
Cap cells – These refer to the top components of cylindrical lithium-ion cells which contain safety hardware, including current interrupt devices, positive temperature co-efficient devices, and pressure burst disks, ensuring electrical insulation and preventing short circuits.
Capillarity – It is the ability of a liquid to flow in narrow spaces or thin tubes without external assistance and frequently against gravity.
Capillary – It refers to a microscopic void, crack, or narrow channel within a material, or a specialized tube used in high-precision manufacturing processes.
Capillary action – It is the phenomenon of intrusion of a liquid into interconnected small voids, pores, and channels in a solid, resulting from surface tension. It is the force by which liquid, in contact with a solid, is distributed between closely fitted faying surfaces of the joint to be brazed or soldered.
Capillary attraction – It is the combined force of adhesion and cohesion which causes liquids, including molten metals, to flow between very closely spaced and solid surfaces, even against gravity. In powder metallurgy, it is the driving force for the infiltration of the pores of a sintered compact by a liquid.
Capillary bore – It refers to an extremely narrow internal diameter (frequently between 20 micrometers to 100 micrometers) inside a slender tube, allowing liquids to move through capillary action.
Capillary, bore – Bore capillary refers to narrow-bore capillaries used in capillary electrophoresis, characterized by an internal diameter of about 20 micrometers to 100 micrometers, which minimizes heating effects and allows for effective separation of analytes under high voltage conditions.
Capillary break – It is a physical gap or non-porous material layer that stops groundwater or soil moisture from moving upward through tiny pores via capillary action. It is a phenomenon which occurs when an unsaturated porous material with larger pores, such as coarse-grained soil or a porous geotextile layer, is situated between fine-grained soils, preventing measurable water flow through the more porous layer. This effect can be utilized to improve water storage or to constrain capillary rise in areas affected by frost or salinity.
Capillary compression – It describes the mechanical deformation, compaction, or volume shrinkage of soft, porous, or particulate materials driven by internal capillary forces (such as surface tension and capillary pressure) as fluid moves through or evaporates from the pore spaces.
Capillary condensation – It is the process where a gas or vapour condenses into a liquid inside the narrow pores or confined spaces of a material at a vapour pressure below the saturation pressure of the pure liquid.
Capillary constant – It is frequently denoted as a-square or related to the capillary length. It is a physical property defined as the product of the capillary radius (or diameter) and the maximum rise or fall height of a liquid inside a narrow tube.
Capillary electro-chromatography – It is a micro-scale separation technique capable of being performed in packed, monolithic, and open-tubular columns. It is an analytical chemistry technique which combines capillary electro-chromatography principles from high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE).
Capillary electrophoresis – It is an analytical laboratory technique which separates charged molecules inside a very thin glass tube, or capillary, using an applied high-voltage electric field.
Capillary force – It is the movement of a liquid through a narrow space or porous material against gravity, driven by the combined effects of adhesion, cohesion, and surface tension.
Capillary gel electrophoresis – It is a technique which utilizes a gel matrix in a capillary tube to rapidly separate and detect fluorescently, allowing for high voltage application without overheating and considerably reduced run times.
Capillary flow porometry – It is an analytical technique used to measure the size, distribution, and permeability of through-pores (pores which completely penetrate a solid material).
Capillary geometry – It refers to the specific physical shape, size, and structural configuration of a narrow channel or pore, such as a circular or non-circular tube, which dictates how fluids move through it through capillary action.
Capillary length – It is the length defined by the balance of capillary and hydrostatic pressures.
Capillary limit – It refers to the maximum thermal load that a heat pipe can handle before the evaporator section dries out, leading to a sharp rise in wall temperature and potential damage, as determined by the capillary head and the wick structure.
Capillary membrane module – It is a filtration unit containing a bundle of small, tube-like capillary membranes with diameters typically ranging from 1 millimeter to 3 millimeters. The small diameter of the tubes allows for a high packing density, fitting a large surface area into a compact volume.
Capillary meter – It consists of a category of precision instruments which utilize the predictable physics of fluid flow through a narrow-bore tube (capillary) to measure or control system variables.
Capillary number – It is a dimensionless parameter in fluid dynamics which measures the relative importance of viscous forces against surface tension forces acting across a fluid-fluid interface.
Capillary pipette – It is a very narrow, calibrated glass or plastic tube which draws and holds tiny, micro-litre-scale volumes of liquid using surface tension and capillary action.
Capillary porosity – It refers to the network of tiny, interconnected pore spaces (ranging from about 10 nano-meters to 1 micrometer in size) found within hardened cement paste in concrete or within porous media.
Capillary pressure curves – These curves refer to graphical representations which depict the relationship between capillary pressure and fluid saturation in rock samples, which are used to analyze pore-size distribution, porosity, and permeability.
Capillary rheometer – It is an apparatus designed to measure shear viscosity and other rheological properties. Capillary rheometers for plastics are piston-die systems designed to measure viscosity of polymer melts as a function of temperature and rate of deformation. They are capable of testing basic polymers, compounds, different composites with small reinforcing particles or fibres, feedstock for metal injection moulding and similar materials.
Capillary space – It is a very narrow opening, pore, or thin tube where liquids can move on their own through capillary action.
Capillary suction – It is the physical process by which a porous material or narrow space draws in a liquid because of the surface tension and adhesive forces.
Capillary thermal mass flow meter – It is a device which directly measures the mass flow rate of clean gases or low-viscosity liquids by tracking heat transfer through a small, heated tube.
Capillary tube – It is a very narrow, thin-walled cylinder used to control fluid flow, measure small liquid samples, or drop pressure in mechanical systems.
Capillary tubing – It is an extremely narrow-diameter pipe, typically with an inner diameter ranging from a fraction of a millimeter to a few millimeters, used to control fluid flow, drop pressure, or transmit thermal and pressure signals.
Capillary water – It is the water held in the small pores of a porous material or fine soil above the groundwater table, moving and staying against gravity through capillary action.
Capital asset pricing model – It is a financial formula used to calculate the expected return on an investment based on its specific risk level compared to the overall market.
Capital cost rate – It is the annualized or time-based cost of building, buying, and installing physical equipment or plants, expressed as a monetary cost per unit of time.
Capital costs – These are fixed, one-time expenses incurred on the purchase of land, buildings, construction, and equipment used in the production of goods or in the rendering of services. In other words, it is the total cost needed to bring a project to a commercially operable status.
Capital equipment – It refers to tangible, durable physical assets used in manufacturing, production, or operations which have a useful life of more than one year and cost above a specific financial threshold. Unlike consumable supplies or inventory meant for resale, these items are recorded as fixed assets on a balance sheet and depreciated over time.
Capital expenditure – It is also called CAPEX. It is the money an organization spends to acquire new fixed physical assets or upgrade old ones, typically for long-term use.
Capital item – It is a long-lasting, high-value physical asset, such as heavy machinery, testing equipment, or structural infrastructure, used to produce goods or services over a period more than one financial year.
Capitalization – It is an accounting method in which a cost is included in an asset’s value and expensed over the asset’s useful life, rather than expensed in the period the cost was incurred. Capitalization recognizes a cash outlay as an asset on the balance sheet rather than an expense on the income statement.
Capitalization on chance – It is the situation in which performing multiple tests of hypothesis raises the probability of rejecting a true null hypothesis beyond the alpha level desired for the group of tests.
Capital recovery factor – It is an economy formula which converts a present lump-sum investment into a series of equal, uniform annual payments over a specific project lifetime at a given interest rate.
Capital repairs – Capital repairs of are those repairs which are taken up after the end of a campaign of the blast furnace. During the capital repairs, the main jobs which are normally taken up are (i) relining of the furnace, (iii) repairs of the damaged portion of the shell, (iii) major revisioning of all the equipment with replacement of the worn out components, (iv) replacement of those equipments, instruments, and automation items which have become obsolete or completed their useful life, and (v) modification work the need of which was felt during the running of the blast furnace in the campaign which has just ended.
Capital services – These refer to the productive flow of work or energy delivered by physical assets, such as machinery, equipment, structures, and tools, over a specific period of time.
Capital works – These refer to major, high-cost construction, expansion, or renovation projects which create, rehabilitate, or upgrade long-term physical assets.
Capital spares – These are critical spares and are usually replaced during the capital repair of the equipment. Hence the procurement action and receipt of these spares are to be planned at the time of taking up of the equipment for the capital repair.
Cap model – It is a representation of plastic behaviour characterized by a yield curve composed of a frictional line and a volumetric cap, where the yield function shows a quarter of an ellipse in the (q, p′)-plane.
Capped steel – It is a type of steel similar to rimmed steel, normally cast in a bottle-top ingot mould, in which the application of a mechanical or a chemical cap renders the rimming action incomplete by causing the top metal to solidify. The surface condition of capped steel is much like that of rimmed steel, but certain other characteristics are intermediate between those of rimmed steel and those of semi-killed steel. The rimming action can be arrested mechanically by putting a heavy steel plate on the top of the surface of the ingot (mechanical capping) or can be stopped by killing by the addition of deoxidizers on the ingot top (chemical capping). The rimming action can also be stopped by spraying water on the top of the ingot.
Capping – It is a protective layer, cover, or structural element placed on top of a surface or material to prevent damage, improve stability, or stop leakage. It also means partial or complete separation of a powder metallurgy compact into two or more portions by cracks which originate near the edges of the punch faces and that proceed diagonally into the compact. In case of abrasive particles, capping is a mechanism of deterioration of abrasive points in which the points become covered by caps of adherent abrasion debris.
Capping layer – It is a supportive, low-cost granular layer placed directly on top of weak natural soil (sub-grade) to form a stable foundation before adding the main road base or sub-base.
Capping material – It is a protective, load-spreading, or isolating layer placed on top of a structure, soil foundation, material sample, or contaminated site.
Cap plasticity – It is a material model used to describe how porous or geologic materials like soils, rocks, concrete, and powders change volume and deform under pressure.
Caprolactone – It is a seven-membered cyclic ester (lactone) with the chemical formula C6H10O2, used mainly as a monomer to manufacture specialized polymers. It is most famous for undergoing ring-opening polymerization (ROP) to create polycaprolactone (PCL), a tough, flexible, and bio-degradable polyester.
Cap-screw – It is a fastener having a head and whose shank is normally threaded throughout its entire length. It is not used with a nut, but rather engagement is made with a female thread in the piece to be joined.
Capstan drive – It is a mechanical power transmission system which uses friction between a rotating drum and a cable, rope, or belt to move or control a load without relying on gear teeth.
Capstan equation – It is also known as the Euler-Eytelwein formula. It is a mathematical rule which shows how a flexible cord, rope, or belt wrapped around a cylinder experiences an exponential change in tension due to friction.
Capstan lathe – It is a machine tool which is used to make the same parts again and again. The cutting bits are mounted on a rotatable turret known as a capstan.
Captive consumer – Captive consumer is an industrial user which generates its own electricity, or co-owns a dedicated power generation facility, to supply mainly its own operational needs rather than relying purely on the public utility grid.
Captive product – It is an accessory, refill, or add-on item which a customer is to buy continuously for a main core product to work. Organization normally price the main core item cheaply to attract buyers, and then charge higher prices for the captive products to make a steady profit over time.
Captive production – It is when an organization makes goods, materials, or energy to use inside its own organization rather than selling them on the open market.
Captive production shop – It is an in-house manufacturing or processing unit owned and operated by a larger parent organization. It exclusively produces parts, components, or services for that parent organization’s own products rather than selling goods or services on the open merchant market.
Capture cross section – It is the effective target area which measures the probability that a particle (such as a neutron) is going to be absorbed by an atomic nucleus without being re-emitted.
Captured image – It is a visual representation of a physical scene or object got through a vision sensor like a camera, scanner, or frame grabber, and converted into a digital data matrix for analysis.
Captured signal – It is a physical or electrical measurement got from a sensor or system which is recorded for analysis, monitoring, or processing.
Capture efficiency – In friction lubrication, it is the cross-sectional area of undisturbed fluid containing particles which ultimately impinges on a given solid surface, divided by the projected area of the solid surface.
Capture velocity – It is the air velocity created by a hood at the point of contaminant generation, sufficient to overcome opposing air currents and transport the contaminant into the hood. For enclosing hoods, this velocity is to be adequate to keep the contaminant within the hood.
Capturing carbon di-oxide – It refers to the process of removing carbon di-oxide (CO2) from flue gases using technologies such as solid amine sorbents, which selectively bind carbon di-oxide through chemical reactions, allowing the gas stream to be depleted of carbon di-oxide before being released back into the atmosphere.
Cap wafer – It is a secondary silicon or glass disk with etched cavities which is bonded directly onto a micro-electro-mechanical system (MEMS) wafer to hermetically seal and protect fragile moving micro-structures.
Caratheodory function – In real analysis and differential equations, it is a function of two variables which is measurable in the first variable and continuous in the second variable.
Carbamate – It is a category of organic compounds with the general formula R2NC(O)OR and structure >N−C(=O)−O−, which are formally derived from carbamic acid (NH2COOH). The term includes organic compounds (e.g., the ester ethyl carbamate), formally obtained by replacing one or more of the hydrogen atoms by other organic functional groups; as well as salts with the carbamate anion H2NCOO- (e.g. ammonium carbamate). Polymers whose repeat units are joined by carbamate like groups −NH−C(=O)−O− are an important family of plastics, the poly-urethanes.
Carbamate formation – It is a chemical reaction where a free amine reacts with carbon di-oxide (CO2) in the presence of water or a base to create a carbamate ion, salt, or ester.
Carbamate polymerization – It is the chemical process of linking monomer units containing carbamate functional groups (also known as urethanes, with the general structure (-NH-C(=O)-O-) to form macro-molecules known as poly-urethanes.
Carbamic acid – It is an unstable chemical compound with the formula H2NCOOH which readily decomposes into ammonia and carbon di-oxide under standard conditions. It contains both an amino group (-NH2) and a carboxylic acid group (-COOH) attached to the same carbon atom. While the pure acid is rarely isolated, its stable salts and esters, known as carbamates, are widely used.
Carbamide – It is also known as urea. It is an organic chemical compound with the formula CO(NH2)2. It features a carbonyl group (C=O) attached to two amine / amide groups (-NH2). It is odourless, white crystalline solid. It is highly soluble in water. It is used as a fundamental raw material to produce urea-formaldehyde resins, plastics, and adhesives. It functions as an additive or blowing / foaming agent ingredient in polymers and rubber production. It is utilized in selective catalytic reduction (SCR) systems (frequently as diesel exhaust fluid) to reduce nitrogen oxide (NOx) emissions from diesel engines.
Carbazole – It is a white, crystalline, aromatic heterocyclic organic compound with the chemical formula C12H9N. It is a poly-cyclic aromatic hydrocarbon comprising two fused six-membered benzene rings and a five-membered nitrogen-containing ring, characterized by extensive electron delocalization. It is normally used as a pi-conjugated bridge in the synthesis of organic dyes for applications in dye-sensitized solar cells.
Carbenium ion – It is also known as a carbocation. It is defined as an electron-deficient reaction intermediate which contains a sp2 hybridized carbon atom with an empty ‘p’ orbital. It serves as a key electrophilic intermediate in several ionization reactions and reacts with different nucleophiles.
Carbide – It is a compound of carbon with one or more metallic elements. It is a binary compound containing carbon in a negative oxidation state, which can form ionic, covalent, or interstitial bonds with metals, showing diverse properties and reactivity, including the production of hydro-carbons upon reaction with water.
Carbide coating – It is a protective thin layer of hard carbide compounds, such as tungsten carbide or chromium carbide, applied to a metal substrate to dramatically improve surface hardness, wear resistance, and durability.
Carbide coagulation – It is the process where smaller carbide particles dissolve into a metal matrix, while larger carbide particles grow larger. This is heavily driven by diffusion along grain boundaries at high operational or tempering temperatures. It is visually and physically identical to Ostwald ripening or carbide coarsening.
Carbide coarsening – It is a phenomenon in which individual carbide particles within a metal matrix increase in average size over time, while their total volume fraction remains relatively constant and their total number decreases. This microstructural change typically occurs when an alloy (such as steel, cast iron, or superalloys) is exposed to high temperatures during heat treatment processes like tempering or prolonged high-temperature operations (e.g., in power plants or jet engines).
Carbide cutter – It is a specialized industrial cutting tool made from tungsten carbide particles bound with a metallic binder like cobalt, designed to remove material from hard work-pieces at high speeds.
Carbide-derived carbon – It is a nearly pure, highly customizable carbon material made by removing metal or non-carbon atoms from metal carbides. It is obtained by extracting metals from carbides through chlorine gas treatment, resulting in either amorphous or crystalline structures.
Carbide films – These are ultra-thin layers of carbide compounds (such as titanium carbide, tungsten carbide, or silicon carbide) deposited onto a substrate material to dramatically improve its surface properties. These films are mainly used to provide extreme hardness, wear resistance, and thermal stability to underlying components without changing the bulk material’s properties.
Carbide formation – It is the chemical process where carbon combines with a metal or semi-metal element at high temperatures to create a hard compound known as a carbide. It is a reaction where carbon atoms bond with less electro-negative or metallic elements, frequently needing heat between 1,000 deg C and 2,800 deg C.
Carbide formers – These are alloying elements which chemically bind with carbon to create stable, hard carbide compounds within iron and steel matrices.
Carbide-free bainitic (CFB) steel – It an advanced high-strength steel characterized by a unique microstructure of ultrafine bainitic ferrite plates interwoven with carbon-enriched retained austenite, completely avoiding the precipitation of coarse cementite or iron carbides. It is made of ultrafine bainitic ferrite laths interwoven with films of retained austenite, completely lacking coarse cementite or carbide particles.
Carbide precipitation – It is a process in which carbon atoms bond with metal alloy elements, very frequently chromium, to form solid carbide particles along the grain boundaries of metals like stainless steel. This reaction typically happens when the metal stays within a critical temperature range of roughly 426 deg C to 871 deg C for too long, such as during improper welding or high-temperature service.
Carbide segregation – It is a defect characterized by the non-uniform distribution and clustering of metal carbides within an alloy’s micro-structure. It typically occurs in high-carbon and highly alloyed steels, and high-speed steels. During solidification, carbon and carbide-forming elements (like chromium, molybdenum, tungsten, and vanadium) reject into the liquid phase, forming heavy concentrations. This localized accumulation leads to dense networks or bands of hard, brittle primary carbides.
Carbide strengthening – It is a mechanism where hard carbide particles are dispersed within a metal’s crystalline matrix to obstruct dislocation movement, hence increasing the material’s strength, hardness, and resistance to wear and deformation.
Carbide tools – It is the cutting or forming tools, normally made from tungsten, titanium, tantalum, or niobium carbides, or a combination of them, in a matrix of cobalt, nickel, or other metals. Carbide tools are characterized by high hardnesses and compressive strengths and can be coated to improve wear resistance.
Carbolic oil – It is also known as light oil and is a complex combination of hydrocarbons obtained by distillation of coal tar. It consists of aromatic and other hydrocarbons, phenolic compounds and aromatic nitrogen compounds and distills at the approximate temperature range of 150 deg C to 210 deg C.
Carbon – It is a non-metallic chemical substance. Carbon has a major effect on steel properties. It is the primary hardening element in steel. Hardness and tensile strength increase as the carbon content increases up to around 0.85 %. Ductility and weldability decrease with increase of the carbon content. Carbon is necessary in steels which are to be hardened by quenching.
Carbon-12 – It is a stable isotope of carbon with 6 protons, 6 neutrons, and 6 electrons, and its atomic mass is exactly 12 atomic mass units (u). It makes up around 98.9 % of all-natural carbon on earth. It acts as the universal reference point for the atomic mass unit (1 u equals 1/12 the mass of a single carbon-12 atom).
Carbon accounting – It is the process of measuring, tracking, and reporting the green-house gas emissions produced by an organization or individual. Like financial book-keeping, instead of tracking money, it tracks climate impact. All green-house gases are converted into a single unified measurement called carbon di-oxide equivalent (CO2e).
Carbon accounting system – It is the accounting process undertaken to measure the quantity of carbon di-oxide equivalents which is not released into the atmosphere as a result of flexible mechanisms projects under the Kyoto Protocol. These projects hence include (but are not limited to) renewable energy projects and biomass, forage and tree plantations.
Carbonaceous – It is a material which contains carbon in any or all of its several allotropic forms.
Carbonaceous fillers – These are carbon-based additive materials mixed into polymers, rubbers, coatings, and composites to improve their mechanical, electrical, and thermal properties.
Carbonaceous material – It is a substance which is rich in, contains, or is composed of the chemical element carbon. Carbonaceous material is also a component of atmospheric aerosols which includes carbon-containing compounds emitted from combustion processes, as well as products formed from the atmospheric oxidation of organic gases. It is typically categorized into elemental carbon (EC), which is associated with soot-like compounds, and organic carbon (OC), which can be vapourized. Carbonaceous materials are the most widely used electrode materials and playing a vital role in electrochemical energy storage devices, because of their abundant resources, very good conductivity, high chemical stability and tunable micro-structure.
Carbonaceous polymer – It typically refers to either a polymer material rich in carbon or a composite system combining carbonaceous fillers (like carbon nano-tubes, graphene, or carbon fibres) with a polymer matrix.
Carbonado – It is a tough, black or dark-grey form of natural diamond used in industry.
Carbon adsorbents – Powder and granular activated carbons are the most well-known and used carbon adsorbents. Carbon adsorbents are used in applications such as controlling volatile organic compounds (VOC) and hazardous air pollutants (HAP) emissions from storage tanks and different vents at different process plants, to control hydrogen sulphide and volatile organic compounds emissions from municipal waste-water plants.
Carbon adsorption – It is a surface process where molecules of gases, vapours, or dissolved substances from a fluid (air or water) stick to the outside and internal pore surfaces of a solid carbon material, normally activated carbon.
Carbon adsorption vapour recovery unit – It is composed of two adsorption vessels filled with activated carbon, a vacuum system used to strip hydrocarbon vapor from the carbon bed during the carbon regeneration process, and a recovery device (absorber or condenser), which turns the regenerated vapours into a liquid product.
Carbon aerogels – These are defined as materials characterized by a continuous, monolithic structure with a high specific surface area (400 square meter per gram to 1,100 square meter per gram) and good electrical conductivity (25 siemens per metre to 100 siemens per metre), which improves their electrosorption capacity. Nitrogen-doped carbon aerogels (CAs), are synthesized through the poly-condensation of melamine, resorcinol, and formaldehyde, followed by carbonization under nitrogen atmosphere.
Carbon allotropes These are the different structural forms of carbon, including graphite, diamond, carbine, and fullerenes, each showing unique physical properties because of the variations in their atomic arrangement.
Carbon arc brazing – It is a brazing process which produces coalescence of metals by heating them with an electric arc between two carbon electrodes. The filler metal is distributed in the joint by capillary action.
Carbon alloy – It is a material made by combining iron with carbon (normally known as carbon steel), or a pure carbon structure modified at the atomic level with other elements to improve its performance.
Carbon anode – It is an electrode made of carbon or graphite which conducts electricity and undergoes oxidation during electro-chemical processes.
Carbon arc – It is an electrical discharge which forms between two carbon or graphite electrodes through the air, producing intense light and extreme heat.
Carbon arc cutting -It is an arc cutting process in which metals are severed by melting them with the heat of an arc between a carbon electrode and the base metal.
Carbon arc welding – It is an arc welding process which produces coalescence of metals by heating them with an arc between a carbon or a graphite electrode and the work. No shielding is used. Pressure and filler metal can or cannot be used. This electrode erodes fairly quickly and generates carbon mono-oxide gas which partially replaces the air around the arc, thereby providing the molten weld with some protection.
Carbonate – It refers to a salt, mineral, or chemical compound containing the carbonate ion [(CO3)2-], or to processes like carbonation and mineral carbonation. It is a carbonate mineral used in materials and construction. It is also the chemical degradation process of carbonation in reinforced concrete.
Carbonate bi-carbonate earth solutions – These refer to natural or engineered aqueous systems dominated by dissolved carbonate [(CO3)2-] and bicarbonate [(HCO3)-] ions which interact with geological materials. These solutions serve as important pH buffers, chemical stabilizers, and carbon carriers across geotechnical, environmental, and civil engineering applications.
Carbonate conditioning – It is a method used in boiler water treatment to prevent scale formation by adding sodium carbonate (Na2CO3). This process converts hard water compounds, like calcium sulphate (CaSO4), into a less harmful form of calcium carbonate (CaCO3), which can be easily removed as sludge. It is mainly used in low-pressure boilers.
Carbonate content – It is the proportion of carbonate compounds, measured as a percentage of the dry weight of a material like soil, rock, or waste.
Carbonated concrete – It is defined as concrete which has undergone progressive neutralization of its alkaline constituents by carbon di-oxide, resulting in the formation of calcium carbonate, which can lead to corrosion of reinforcing steel once the carbonated surface reaches the steel depth.
Carbonate hardness – It is a measure of water hardness caused by the presence of carbonate and bi-carbonate ions, mostly bound to calcium and magnesium.
Carbonate ion – It is a poly-atomic ion with the chemical formula [CO3)2-]. It contains one carbon atom bonded to three oxygen atoms. It carries a net electrical charge of -2. It has a flat, trigonal planar molecular geometry. The bonds share electron density equally across all three oxygen atoms through resonance.
Carbonate reservoirs – These are geological formations mainly composed of carbonate rocks such as limestones and dolomites, which can contain substantial quantities of oil and gas trapped within their natural fractures. These reservoirs show complex characteristics and productivity which depend on factors such as fracture density, connectivity, and size.
Carbonate rocks – These are sedimentary rocks which contain more than 50 % carbonate minerals, mainly consisting of calcite and dolomite, and are frequently formed from the biogenic and chemical precipitation of calcium carbonate in shallow marine environments.
Carbonate sand – It is a type of sediment made mostly of calcium carbonate or magnesium carbonate rather than quartz. It forms mainly from the broken-down skeletal remains of marine organisms like corals, mollusks, algae, and foraminifera.
Carbonate soils – These are soils which contain substantial quantities of carbonate minerals, very frequently calcite and dolomite, which directly control the soil’s chemical behaviour, structure, and alkaline pH.
Carbonate solutions – These are liquid mixtures used in industrial plants to absorb and remove acid gases like carbon di-oxide (CO2) and hydrogen sulphide (H2S) from gas streams.
Carbonation – It is frequently referred to as mineral carbonation or carbon mineralization. It is the chemical reaction of carbon di-oxide (CO2) with metal oxides, hydroxides, or silicates contained in ores, metallurgical residues, or basic slag to form stable solid metal carbonates.
Carbonation front – It is the transition boundary inside concrete where atmospheric carbon di-oxide (CO2) reacts with alkaline hydration products, causing the internal pH to drop from a high alkaline state above 12 to a neutral state below 9.
Carbonation-induced corrosion – It is the rusting of steel bars inside concrete caused by carbon di-oxide from the air lowering the concrete’s natural alkalinity.
Carbonation of concrete – It is a chemical process where carbon di-oxide from the air enters the concrete and reacts with moisture and calcium hydroxide to form calcium carbonate.
Carbonation process – It is the physical and chemical reaction in which atmospheric carbon di-oxide penetrates into materials, leading to the formation of calcium carbonate through reactions with calcium hydroxide, aluminates, and silicates. This process can negatively affect alkali-activated materials and initiate rebar corrosion in reinforced concrete. In geology, carbonation process is a type of chemical weathering where rainwater containing dissolved carbon di-oxide (carbonic acid) reacts with minerals like limestone.
Carbonation resistance – It is the ability of concrete and cement-based materials to stop carbon di-oxide (CO2) and moisture from entering and lowering the material’s internal pH.
Carbonatite – It is an igneous rock which consists chiefly of carbonate minerals crystallized from a carbonate magma, typically containing more than 30 modal % of igneous carbonates. The most common variety, sovite, is mainly composed of calcium carbonate along with other minerals such as mafic silicates and fluorite.
Carbonatite reservoir – It is a sub-surface geological formation composed predominantly of [carbonatite], an uncommon type of intrusive or extrusive igneous rock containing more than 50 volume percent main carbonate minerals (such as calcite or dolomite), which possesses sufficient porosity and permeability to store and yield fluids like oil, natural gas, or water.
Carbon atom – It is a tetravalent chemical element (symbol ‘C’, atomic number 6) defined by its four valence electrons, enabling it to form strong covalent single, double, or triple bonds and versatile structural networks.
Carbon-based anode – It is a negative electrode material made from carbon or graphite which conducts electricity and stores or facilitates electro-chemical reactions during charging. These materials are prized for their high electrical conductivity, chemical stability, and natural abundance.
Carbon-based fuel – It is an energy source derived from carbon-containing materials which releases stored chemical energy through oxidation or combustion with oxygen.
Carbon-based materials – These are substances consisting mainly of carbon atoms which form versatile nano-structures, allotropic variations, and composites prized for exceptional strength, conductivity, and thermal stability.
Carbon bed – It is a filtration system packed with porous granular activated carbon used to trap pollutants and impurities from passing gas or liquid streams.
Carbon black – It is used to increase strength and abrasion resistance of a rubber compound. Smaller particles provide better reinforcement but are more difficult to process.
Carbon blocks – These are refractories made of carbon and are used for lining of hearth bottom and hearth walls.
Carbon boil – It is the rapid release of carbon mono-oxide (CO) gas bubbles rising to the surface of molten steel during refining. This bubbling action happens when dissolved carbon reacts with oxygen inside the high-temperature metal melt.
Carbon bonded dolomite bricks – Dolomite bricks are also made in carbon-bonded compositions. The carbon-bonded varieties include both pitch and resin-bonded alternatives. Some of the carbon-bonded bricks contain flake graphite and are somewhat analogous to magnesite-carbon brick.
Carbon burning – It is a nuclear fusion process which occurs in the centre of a star after a contraction phase, mainly producing neon-20 from carbon-12, along with magnesium-24 and sodium-23, while also continuing the s-process through reactions involving unburned neon-22.
Carbon, burning – Burning carbon refers to the process of combusting carbon-containing materials, resulting in the production of carbon mono-oxide (CO) and carbon di-oxide (CO2) as flue gas components, which can be quantified to calculate the carbon burning rate and conversion efficiency.
Carbon capture – It is a technology which traps carbon di-oxide (CO2) emissions from industrial smoke-stacks or the open air before it can escape into the atmosphere and warm the planet. It is a technology aimed at mitigating climate change by capturing carbon di-oxide from large point sources, such as power plants, and securely storing it instead of releasing it into the atmosphere.
Carbon capture and storage – It is also called sequestration. It involves the capture, transport, injection and containment of carbon di-oxide in geological structures such as depleted oil and gas reservoirs, onshore and offshore saline aquifers located deep in the earth’s crust, salt caverns or unmineable coal beds. It is both an approach to enhance production from existing oil and gas operations as well as a means for reducing green-house gas emissions. Carbon capture and storage provides an additional alternative in the utilization of fossil-fuel based energy, while providing additional transition time for energy systems to move towards carbon reduced or zero carbon fuels, such as renewables.
Carbon capture and storage system – It is a three-step technology process which traps carbon di-oxide (CO2) emissions from industrial sources or power plants, moves the gas to a secure location, and stores it deep underground to stop it from warming the atmosphere. A complete carbon capture and storage (CCS) system comprises three main components: carbon capture, transport, and storage or sequestration.
Carbon capture and storage technology – It is a technology which involves capturing carbon di-oxide (CO2) emissions from sources such as power plants and industrial processes, transporting the captured carbon di-oxide, and storing it in geological formations to prevent its release into the atmosphere.
Carbon–carbon bond – It is a covalent chemical bond, a link formed by sharing electrons, between two carbon atoms in an organic molecule. There are three types of bonds. Single bond shares two electrons (one from each carbon atom). It is a strong sigma bond, common in alkanes like ethane. Double bond shares four electrons between two carbon atoms. It consists of one sigma bond and one pi bond, found in alkenes like ethene. Triple bond shares six electrons between two carbon atoms. It consists of one sigma bond and two pi bonds, found in alkynes like ethyne.
Carbon-carbon composite – It is a composite composed of continuous fibres of carbon or graphite which are embedded in a carbon or graphite matrix. The matrix has been originally a polymer resin which has been subsequently pyrolyzed to form carbon.
Carbon-ceramic refractory – It is a manufactured refractory comprised of carbon (including graphite) and one or more ceramic materials such as fireclay and silicon carbide.
Carbon chain – It is a sequence of carbon atoms linked together by covalent bonds, which serves as the fundamental structural backbone for organic molecules and polymer-based engineering materials. The term describes the precise atom-level modification or tuning of carbon structures to control electronic properties, lower activation energy barriers, and optimize catalytic performance for reactions like propane dehydrogenation.
Carbon coatings containing metal – These are frequently called metal-doped diamond-like carbon. These are hybrid composite thin films made of an amorphous carbon matrix embedded with metallic nano-particles or micro-particles. These combine a disordered carbon network (featuring sp2 and sp3 carbon bonds) with transition metals or noble metals such as titanium (Ti), silver (Ag), tungsten (W), silicon (Si), or chromium (Cr).
Carbon composite – It is an advanced material which consists of carbon fibres reinforced within a carbon matrix, showing a wide range of properties because of variations in crystallinity, fibre architectures, and volume fractions. These composites are known for their exceptional dimensional stability at high temperatures, mechanical reliability, and remarkable wear resistance, making them suitable for applications such thermal management systems.
Carbon concentration – It is the total quantity of carbon present in a specific volume, area, or substance, typically measured in units like parts per million (ppm) or milligrams per litre.
Carbon-containing source – It is a material which supplies carbon elements for chemical, or metallurgical processes.
Carbon content – It is the proportion of carbon, measured by weight percentage, present in an iron-based alloy like steel or cast iron. This tiny quantity of carbon acts as the main control switch for the metal’s mechanical properties. It dictates how hard, strong, and brittle the final material becomes.
Carbon conversion efficiency – It is the ratio of carbon atoms in the desired product to the total carbon atoms in the feedstock fed into a chemical or biological system. It quantifies how effectively a process transforms raw carbon inputs (like biomass, coal, natural gas, or captured carbon di-oxide) into valuable outputs (like synthetic fuels, chemicals, or materials) rather than losing it as waste emissions or by-products.
Carbon conversion rate – It measures the percentage of solid or gaseous carbon in a feedstock that successfully turns into a desired gaseous or chemical product during a thermal or catalytic process.
Carbon cycle – It is the term used to describe the flow of carbon (in different forms, e.g., as carbon di-oxide) through the atmosphere, ocean, terrestrial biosphere, and lithosphere.
Carbon deposition – It is the accumulation of carbon on a surface, such as a catalyst, engine part, or refractory material, during catalytic transformations of hydro-carbons, which can lead to catalyst deactivation through mechanisms such as blockage of active sites, encapsulation of metal crystals, and destruction of the catalyst’s structure. It is the accumulation of solid carbon on a surface, such as a catalyst, engine part, or refractory material, caused by the breakdown or reaction of carbon-containing gases and hydro-carbons.
Carbon deposits – These refer to solid carbon material formed from the dissociation of carbon oxides or the decomposition of hydrocarbons, with coke being a specific type produced from higher hydrocarbons through coking processes. The formation of carbon deposits can occur through different reactions, including methane decomposition and the Boudouard reaction, and is influenced by the presence of aromatic and polyaromatic structures. Carbon deposits are also hard, black soot-like layers that build up on internal engine parts when fuel and oil do not burn completely.
Carbon diffusion model – It is a mathematical and physical representation of how carbon atoms migrate through a metal’s crystal lattice over time and temperature.
Carbon di-oxide – Carbon di-oxide is a chemical compound. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It does not burn, and in standard temperature and pressure conditions it is stable, inert, and non-toxic. It is a green-house gas.
Carbon di-oxide activation – It is the chemical or physical process of changing a stable, unreactive traps carbon di-oxide (CO2) molecule so its electronic and geometric properties become reactive enough to undergo chemical transformation or material bonding. Since a normal carbon di-oxide molecule is very stable and linear (a straight line with an 180-degree angle), it needs energy, catalysts, or specific surface interactions to activate.
Carbon di-oxide capture – It is the process of separating carbon di-oxide (CO2) emissions from industrial exhaust or directly from the ambient air using chemical solvents, solid sorbents, or membranes to prevent it from entering the atmosphere.
Carbon di-oxide capture and storage – It is a three-step process which traps carbon di-oxide emissions from power plants or factories, moves the gas, and buries it deep underground to keep it out of the air.
Carbon di-oxide content – It refers to the proportion of carbon di-oxide in flue gases, which serves as a main indicator of the effectiveness of combustion of hydro-carbon fuels and the adequacy of excess air supplied to burners. The presence of carbon di-oxide (CO2) is influenced by the carbon to hydrogen ratio in the fuel, with higher carbon content resulting in higher carbon di-oxide emissions.
Carbon di-oxide control – It refers to the management, regulation, or reduction of carbon di-oxide (CO2) levels within a specific environment or industrial process to ensure safety, optimize efficiency, or meet environmental standards.
Carbon di-oxide control technologies – These technologies refer to the development and implementation of technologies aimed at capturing and managing carbon di-oxide (CO2) emissions from sources such as coal-fired power plants to mitigate global warming, with a goal of achieving substantial capture efficiency at a commercial scale.
Carbon di-oxide corrosion – It is also known as sweet corrosion. It is the electro-chemical deterioration of carbon and low-alloy steels caused when carbon di-oxide dissolves in liquid water to form a weak carbonic acid. This type of degradation is common in industrial settings like oil and gas production pipelines, boiler condensate systems, and petrochemical plants. Dry carbon di-oxide gas is not corrosive, but the presence of free water triggers an acidic reaction which dissolves iron and forms an iron carbonate scale.
Carbon di-oxide electro-reduction – It is an electro-chemical process which converts carbon di-oxide into valuable chemicals, fuels, and feedstocks using electrical energy and specialized catalysts.
Carbon di-oxide flooding – It mainly refers to an ‘enhanced oil recovery’ (EOR) technique in which carbon di-oxide is injected into an oil reservoir to enhance oil recovery, particularly in reservoirs deeper than 600 meters, by creating a miscible zone which facilitates the movement of oil toward production wells. It also describes a fixed fire suppression method used in industrial safety.
Carbon di-oxide hydrogenation – It is a catalytic chemical process which reacts carbon di-oxide with molecular hydrogen (H2) to convert a green-house gas into valuable fuels and chemical feedstocks.
Carbon di-oxide laser – It is a gas molecular laser which uses a mixture of carbon di-oxide, nitrogen, and helium to produce high-power, continuous-wave infrared light.
Carbon di-oxide monitors – These monitors work by giving an indication of how well-ventilated an area is. These monitors help to identify any areas of poor ventilation, allowing people to make the necessary changes to keep fresh air flowing, whether that be through mechanical ventilation or ensuring doors and windows are open. These monitors measure the concentrations of carbon di-oxide in parts per million (ppm).
Carbon di-oxide process – It is a process for hardening moulds or cores in which carbon di-oxide gas is blown through dry clay-free silica sand for precipitating silica in the form of a gel from the sodium silicate binder.
Carbon di-oxide reduction – It is the chemical or electro-chemical process of converting carbon di-oxide (CO2) into useful products like fuels, chemicals, and energy.
Carbon di-oxide storage – It is the process of injecting anthropogenic carbon di-oxide (CO2) emissions deep into underground geological formations for permanent sequestration.
Carbon di-oxide super-critical extraction – It is an advanced separation process using pressurized carbon di-oxide (CO2) above its critical point as a solvent to isolate target compounds from a matrix.
Carbon di-oxide to methanol – It is a catalytic process which transforms captured carbon di-oxide and green hydrogen to produce methanol (CH3OH), which addresses both environmental and economic challenges associated with green-house gas emissions. This process can be achieved through different methods, including hydrogenation reactions, and aims to reduce the carbon footprint of methanol production.
Carbon di-oxide utilization – It is the process of capturing waste CO2 from industrial point sources or the atmosphere and converting it into valuable commercial products like chemicals, fuels, and building materials.
Carbon di-oxide welding – It is a non-standard term for gas metal arc welding which is an arc welding process that produces coalescence of metals by heating them with an arc between a continuous filler metal electrode and the work-pieces. Shielding is done entirely from an externally supplied gas.
Carbon distribution – It refers to how carbon atoms are arranged, spread, or concentrated throughout a material’s microscopic structure. It mainly dictates the mechanical properties of steel and iron alloys.
Carbon dots – These are zero-dimensional carbon nano-particles smaller than 10 nano-meters which feature a carbon core and reactive surface groups.
Carbon double bond – It is an unsaturated covalent bond where two carbon atoms share four electrons instead of two. It consists of one sigma bond and one pi bond, found in alkenes like ethene.
Carbon economy – It is frequently framed as a circular carbon economy (CCE). It is a systemic framework which manages carbon flows through technology, engineering processes, and infrastructure to achieve net-zero greenhouse gas emissions. Instead of treating carbon di-oxide (CO2) solely as waste, this model views carbon as a manageable resource and engineering challenge. Carbon economy is based on four pillars known as the 4 Rs which are reduce, reuse, recycle, and remove.
Carbon edges – These are carbonaceous deposits in a wavy pattern along the edges of a steel sheet or strip. It is also known as snaky edges.
Carbon electrode – It is a non-filler material electrode used in arc welding or cutting, consisting of a carbon or graphite rod, which can be coated with copper or other coatings. The carbon electrodes are of three grades namely (i) plain, (ii) uncoated, and (iii) copper coated. Applications include carbon arc welding, twin carbon arc welding, carbon cutting, and air carbon arc cutting and gouging.
Carbon emission pinch analysis – It is a systematic process integration methodology used to plan energy allocation networks under strict carbon footprint constraints. Carbon emission pinch analysis (CEPA) is a macro-scale variant of traditional pinch analysis. Instead of matching hot and cold streams for heat recovery, it treats carbon intensity as the quality factor for matching available energy sources with energy demands. It considers carbon footprint constraints, determining the optimal budget for low-carbon or zero-carbon energy resources while matching energy sources to energy demands.
Carbon enrichment – It normally refers to the deliberate process of increasing the carbon concentration within a specific metal matrix, phase, or surface layer to alter its microstructural and mechanical properties. Carbon enrichment is also the process of increasing carbon di-oxide (CO2) levels in a controlled environment or experimental setting above normal atmospheric concentrations.
Carbon-epoxy laminate – It is an advanced composite laminate made by stacking multiple layers of carbon fibre plies bound together and cured with a rigid epoxy resin matrix.
Carbon-epoxy composites – These are advanced structural materials made of high-strength carbon fibres embedded in a continuous epoxy resin matrix.
Carbon equivalent – For cast iron, it is an empirical relationship of the total carbon, silicon, and phosphorus contents expressed by the formula given be equation CE = % C + 0.3(% Si) + 0.33(% P) – 0.027(% Mn) + 0.4(% S). For determination of weldability. Carbon equivalent is expressed by equation CE = C + Mn/6 + Ni/15 + Cu/15 + Cr/5 + Mo/5 + V/5.
Carbon fibre – It is the fibre produced by the pyrolysis of organic precursor fibres, such as rayon, poly-acrylo-nitrile (PAN), and pitch, in an inert environment. The term is frequently used interchangeably with the term graphite. However, carbon fibres (CFs) and graphite fibres differ. The basic differences lie in the temperature at which the fibres are made and heat treated, and in the amount of elemental carbon produced. Carbon fibres typically are carbonized in the region of 1,315 deg C and assay at 93 % to 95 % carbon, while graphite fibres are graphitized at 1,900 deg C to 2,480 deg C and assay at more than 99 % elemental carbon.
Carbon fibre composites – These are high-performance engineering materials made by embedding woven or aligned carbon fibres inside a cured epoxy resin matrix. In this combination, the carbon fibres provide exceptional tensile strength and stiffness, while the thermosetting epoxy resin acts as a binder which holds the fibres in alignment, protects them from damage, and transfers mechanical loads between them.
Carbon fibre filament – These filaments refer to a class of filaments made from different base materials which have tiny carbon fibres (CFs) infused in them in order to improve the properties of base material.
Carbon fibre material – It is a light-weight, exceptionally strong substance made of thin crystalline carbon filaments bonded together. It is very frequently used as a reinforcing additive in carbon fibre (CF) reinforced polymer composites or carbon fibre filaments for manufacturing and 3D printing.
Carbon fibre paper – It is a thin, porous, and electrically conductive sheet material made from short carbon fibres using wet or dry papermaking processes. It is composed mainly of chopped carbon fibres bound together with resins or additives. It offers high electrical and thermal conductivity and features a specialized pore structure which allows high gas and fluid permeability.
Carbon fibre production – It is the industrial process of synthesizing lightweight, high-strength carbon filaments, mainly from a polymer precursor like poly-acrylo-nitrile (PAN), through spinning, thermal stabilization, and high-temperature carbonization.
Carbon fibre reinforced plastic – It is defined as a composite material which combines properties-giving carbon fibres with a form-holding matrix, resulting in a high-performance compound which is light-weight and possesses remarkable strength. It is increasingly used in different applications.
Carbon fibre reinforced polymer – It is also known as carbon fibre reinforced plastic, or carbon fibre reinforced thermo-plastic. It is an extremely strong and light fibre-reinforced plastic which contains carbon fibres.
Carbon fibre reinforcement – It refers to the process of strengthening a material by incorporating carbon fibres into a polymer matrix, creating a composite material known as carbon fibre-reinforced polymer (CFRP). The carbon fibres provide high strength and stiffness, while the polymer matrix holds the fibres together and contributes to toughness.
Carbon fibre-reinforced polymer composite – It is an extremely strong, rigid, and lightweight composite material made of carbon fibres bound together by a polymer resin matrix.
Carbon flotation – It is the free graphite which has separated from the molten iron in a cast iron. This imperfection tends to occur at the upper surfaces of the cope of castings.
Carbon fluoride – It refers to a class of solid, layered materials or gases formed by combining carbon and fluorine, typically represented by the empirical formula CFx. Solid carbon fluorides (like carbon mono-fluoride) are non-stoichiometric fluoro-carbons with varying fluorine-to-carbon ratios. They are made by reacting elemental fluorine gas with carbon sources like graphite or charcoal at high temperatures. These materials are highly hydrophobic (water-repellent), thermally stable, and chemically resistant.
Carbon footprint – It is also known as greenhouse gas footprint. It is a calculated value or index which makes it possible to compare the total quantity of greenhouse gases which an activity, product, or an organization adds to the atmosphere. Carbon footprints are normally reported in tons of emissions (carbon di-oxide- equivalent) per unit of comparison. A product’s carbon footprint includes the emissions for the entire life cycle. These run from the production along the supply chain to its final consumption and disposal. Similarly, an organization’s carbon footprint includes the direct as well as the indirect emissions that it causes.
Carbon form – It describes how carbon atoms bond together. It refers to the different structural configurations of carbon, including amorphous, vitreous, graphite, and diamond, each showing distinct physical properties and stability under different conditions, with graphite being the most stable and normally encountered form in carbon matrix composites (CMCs).
Carbon-free energy source – It is an electricity generation method which produces zero direct carbon di-oxide or green-house gas emissions during operation.
Carbon-free sources – These sources refer to energy sources which do not emit carbon di-oxide during their production and use, allowing for the potential replacement of fossil fuels and contributing to carbon di-oxide (CO2) reduction.
Carbon fuel – It is a solid, liquid, or gaseous substance containing carbon which is burned to release stored chemical energy as heat.
Carbon fullerene – It is a hollow molecule made entirely of carbon atoms linked together in a closed, cage-like 3D shape. Carbon atoms form a pattern of interconnected hexagons and pentagons (and sometimes heptagons). Carbon fullerenes are spherical cages composed of 28 to more than 100 carbon atoms, structured from interconnected carbon pentagons and hexagons, resembling a soccer ball. The most famous type is buck-minster-fullerene (C60), which has 60 carbon atoms and looks like a soccer ball. They can also form tubes, known as carbon nano-tubes, or oval shapes. The empty space inside allows them to trap other atoms or molecules. They show unique physical properties, potential applications in nano-electronics.
Carbon gradient – It is frequently called a carbon profile. It is the continuous variation of carbon concentration as a function of distance from the surface into the core of a metallic workpiece. It is governed by Fick’s laws of diffusion. During thermal treatments like carburizing, carbon atoms are introduced to the surface of a low-carbon steel component. Over time, these atoms migrate inward toward areas of lower concentration.
Carbon-hydrogen ratio – It is also called hydrogen-carbon ratio. Atomic / molar ratio refers to the proportion of hydrogen to carbon atoms in a fuel, with higher ratios indicating higher energy efficiency and lower carbon di-oxide (CO2) emissions during combustion. It compares the number of moles of carbon atoms to hydrogen atoms (or vice versa). It is calculated by dividing the mass percentage of each element by its atomic weight (carbon around 12 grams per mol, hydrogen around 1 gram per mol C). Mass ratio compares the total weight of carbon to the total weight of hydrogen in a sample (e.g., an 80 % carbon and 5 % hydrogen-coal yields a carbon / hydrogen ratio of 16:1).
Carbonic acid – It is a weak, unstable chemical compound with the formula H2CO3 which forms when carbon di-oxide dissolves in water.
Carboniferous rocks – These are layers of the earth’s crust formed during the carboniferous Period (around 359 million years to 299 million years ago) which are well-known for containing major coal beds.
Carboniferous system – It is the sequence of rock strata formed during the carboniferous period, the fifth interval of the Paleozoic era lasting from roughly 358.9 million years to 298.9 million years ago.
Carbon incorporation – It is the process of controlling the quantity of carbon present in a crystal, which is necessary for achieving high-quality, semi-insulating crystals with reproducible properties. The carbon concentration directly affects the electrical characteristics of devices fabricated from the crystal, such as the threshold voltage of MESFETs (metal–semiconductor field-effect transistors) .
Carbon injection – Injection of carbon in electric arc furnace brings the benefits of (i) for 100 % scrap practice or when carbon content of the bath is insufficient to produce carbon mono-oxide gas for slag foaming, carbon injection is beneficial, and (ii) carbon oxidation produces carbon mono-oxide gas which on post combustion generates thermal energy. It is to be noted that carbon injection requires oxygen injection to onset carbon oxidation.
Carbo-nitrided steel – It is the steel which has undergone a surface heat treatment to absorb both carbon and nitrogen, creating a hard, wear-resistant outer layer while keeping a tough inner core. This process is a modification of gas carburizing. It is performed by heating low-carbon or medium-carbon steel in a special gas atmosphere, typically a hydrocarbon gas like methane or propane mixed with ammonia, at temperatures between 820 deg C and 900 deg C.
Carbo-nitrides – These are defined as solid solutions formed by the combination of carbides and nitrides of transition metals, where their physical and chemical properties vary significantly based on the carbon-to-nitrogen ratio.
Carbo-nitride segregation – It refers to the uneven distribution or localized accumulation of carbo-nitride particles (compounds containing both carbon and nitrogen combined with metal elements like titanium, niobium, or vanadium) within a metal’s micro-structure.
Carbo-nitriding – It is a case-hardening process in which a suitable ferrous material is heated above the lower transformation temperature in a gaseous atmosphere of such composition as to cause simultaneous absorption of carbon and nitrogen by the surface and, by diffusion, create a concentration gradient. The heat-treating process is completed by cooling at a rate which produces the desired properties in the work-piece. Carbo-nitriding is used mainly to impart a hard, wear-resistant case, normally from 0.075 millimeters to 0.75 millimeters deep. A carbonitrided case has better hardenability than a carburized case (nitrogen increases the hardenability of steel, it is also an austenite stabilizer, and high nitrogen levels can result in retained austenite, particularly in alloy steels). Consequently, by carbo-nitriding and quenching, a hardened case can be produced at less expense within the case-depth range indicated, using either carbon or low-alloy steel. Full hardness with less distortion can be achieved with oil quenching, or, in some cases, even gas quenching, using a protective atmosphere as the quenching medium.
Carbonium ion – Itis a positively charged organic ion where a carbon atom has five bonds (penta-coordinated) instead of the usual four.
Carbonization – It is the high-temperature conversion of an organic substance into elemental carbon. In coke making, carbonization is a process in which coal is heated in the absence of oxygen. After combustion, carbonization of coal is the most important use of coal to produce coke.
Carbonization furnace – It is an industrial heating system used to thermally decompose organic or carbonaceous materials in an oxygen-deprived environment.
Carbonization of coal – It is also known as coking of coal. The process consists of thermal decomposition of coals either in the absence of air or in controlled atmosphere to produce a carbonaceous residue known as coke.
Carbonization process – It is the destructive distillation of organic substances in the absence of air, resulting in the production of carbon along with liquid and gaseous products, typically at temperatures up to 1,500 deg C.
Carbonizing flame – It is the reducing flame. It is an oxy-fuel gas flame produced when there is a higher ratio of acetylene to oxygen than what is needed for neutral combustion.
Carbon laminate – It is a high-strength composite material made by layering carbon fibres bonded together with a polymer resin, such as epoxy. It offers extreme tensile strength and rigidity while remaining very lightweight. Unlike steel, it does not rust or degrade in harsh chemical or environmental conditions. Its mechanical behaviour can be adjusted by changing the orientation and stacking angles of the fibre layers.
Carbon layer – It refers to a microscopic sheet, film, or structural plane of carbon atoms, such as the hexagonal atomic sheets in graphite or engineered coatings applied to materials like silicon in battery anodes. In crystalline carbon forms like graphite, a carbon layer is a single two-dimensional planar sheet of carbon atoms bonded in a repeating hexagonal ‘chicken wire’ pattern. These parallel stacked layers slide easily past each other, making graphite soft. In energy storage (coating), a carbon layer is an applied protective or conductive coating (frequently on battery materials like silicon composites) which improves structural stability, electrical conductivity, and lifespan. In power systems, a carbon layer describes an analytical and verifiable accounting dimension used to measure how much a clean energy source displaces a carbon-intensive baseline.
Carbon–manganese ferritic steel – It is an unalloyed or low-alloy steel featuring a body-centered cubic ferrite micro-structure, strengthened mainly by controlled quantities of carbon and manganese. It has low carbon content (typically under 0.2 %) combined with manganese levels normally ranging up to 1.65 % to 1.8 %. Its micro-structure is dominated by ferrite (alpha-iron) with minimal pearlite, ensuring good ductility and formability. It provides low creep resistance, limiting use to sub-critical conditions below 450 deg C. It offers an economical balance of strength, toughness, and ease of welding.
Carbon manganese steels – These steels refer to a family of medium to high strength steels which through a combination of correct selection of chemical composition and hot rolling mill processing parameters produce products with enhanced formability and toughness. The manganese content in these steels is increased for the purpose of increasing depth of hardening and improving strength and toughness. Carbon steels containing higher than 1.2 % and up to around 1.8 % manganese are referred to as carbon manganese steels.
Carbon-mark – It is gray or black surface marking caused by contact with carbon run-out blocks.
Carbon market – It is a trading system where organizations buy and sell carbon credits to lower global green-house gas emissions. One carbon credit equals the reduction or removal of one metric ton of carbon di-oxide or another green-house gas.
Carbon microspheres – These are tiny, spherical carbon particles with diameters typically ranging from 100 nano-meters to 100 micro-meters. They belong to the family of zero-dimensional carbon nano-materials and are known for having large surface areas, tunable pore structures, and high chemical and thermal stability.
Carbon molecular sieve – It is a porous, carbon-based adsorption material with tiny, uniform micropores designed to separate gas mixtures based on molecular size and diffusion rates.
Carbon molecular sieve membrane – It is a high-performance, porous carbon-based barrier which separates gas mixtures at a molecular level based on size and diffusion speed.
Carbon mono-oxide – Carbon mono oxide is a poisonous, flammable gas which is colourless, odourless, tasteless, and slightly less dense than air. Carbon mono-oxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest carbon oxide. It is predominantly produced by incomplete combustion of carbon-containing materials.
Carbon mono-oxide disintegration – It is breakdown of a refractory caused by the deposition of carbon resulting from the dissociation of carbon mono-oxide.
Carbon mono-oxide methanation reaction – It is an exothermic catalytic reaction which converts carbon mono-oxide and hydrogen into methane and water.
Carbon mono-oxide resistance – It is the resistance of a refractory to carbon mono-oxide disintegration when exposed to carbon mono-oxide under specified conditions of atmosphere and temperature.
Carbon nano-fibres – These are cylindrical nano-structures composed of carbon atoms with diameters typically ranging from 50 nano-meters to 200 nano-meters and layered graphene sheets arranged in stacked cones, cups, or plates.
Carbon nano-particle – It is a microscopic particle made of carbon with a size of less than 100 nano-meters. It is built entirely from carbon atoms arranged in different structural forms. It is very good conductor of heat and electricity. It has exceptional mechanical strength and high surface area.
Carbon nano-structures – These are microscopic architectures made entirely of carbon atoms arranged in specific patterns at the nano-scale, featuring unique mechanical, electrical, and thermal properties.
Carbon nano-tube pellets – These are densified, compact forms of carbon nano-tubes manufactured to eliminate the safety and handling hazards of fluffy, easily scattered raw powders. These are a compacted form of carbon nano-tubes bound together through dry compression or wet granulation (using minimal solvents or binders) or pre-dispersed into a carrier polymer resin (master-batch pellets).
Carbon nano-tubes – These are hollow, cylindrical carbon allotropes made from rolled sheets of graphene. These are cylindrical molecules with a nano-meter-scale diameter and a very high length-to-diameter ratio. Carbon nano-tubes (CNTs) are classified as single-walled carbon nano-tubes (SWCNT) with one layer or multi-walled carbon nano-tubes (MWCNT) with multiple concentric layers. These tubes have very good tensile strength, high electrical and thermal conductivity, and low density.
Carbon nano-tube synthesis – It is the process of producing cylindrical carbon molecules, known as carbon nano-tubes (CNTs), using specialized physical or chemical methods.
Carbon-neutral building – It is a structure designed, constructed, and operated to achieve a net-zero carbon footprint by minimizing green-house gas emissions and balancing any remaining emissions through offsets.
Carbon-neutral cycle – It is a closed-loop process where carbon di-oxide released into the atmosphere is balanced by an equal quantity absorbed, resulting in zero net increase in atmospheric carbon.
Carbon neutrality – It means having a balance between emitting carbon and absorbing carbon from the atmosphere in carbon sinks. Carbon neutrality is reached when the same quantity of carbon di-oxide released into the atmosphere as is removed by various means, leaving a zero balance, also known as a zero-carbon footprint.
The carbon:nitrogen (C:N) ratio – It refers to the relationship between the quantities of carbon and nitrogen present in organic materials, with an optimum range for effective anaerobic digestion typically between 25:1 and 35:1. This ratio can be adjusted by mixing materials with varying C:N ratios to achieve the desired balance.
Carbon oxidation – It is a chemical process where a carbon atom loses electron density, typically by gaining bonds to more electronegative atoms like oxygen or losing bonds to hydrogen.
Carbon oxidation demand – It is normally measured as chemical oxygen demand (COD). It is the total quantity of oxygen needed to chemically break down organic and inorganic carbon compounds in water into carbon di-oxide and water.
Carbon paper – It is frequently called carbon fibre paper. It is a thin, porous, electrically and thermally conductive composite material made of carbon fibres held together by a carbon binder.
Carbon particulates – These refer to microscopic solid or liquid carbon-based particles suspended in a gas, liquid, or solid matrix, originating mainly from incomplete combustion or carbon nano-materials.
Carbon potential – It is a measure of the ability of an environment containing active carbon to alter or maintain, under prescribed conditions, the carbon level of a steel. In any particular environment, the carbon level attained depends on such factors as temperature, time, and steel composition.
Carbon price – It is a monetary cost applied to each ton of greenhouse gas emissions to internalize the external environmental costs of pollution and incentivize emission reductions.
Carbon profile – It is the variation of carbon concentration as a function of time and distance from the surface of a material (such as steel during diffusion treatments like carburizing). It is governed by Fick’s laws of diffusion, showing how carbon atoms penetrate a metal lattice. It is driven by temperature, processing time, surface carbon potential, and alloying elements. It determines localized hardness, wear resistance, and microstructure gradients (e.g., case hardening).
Carbon quantum dots – These are zero-dimensional carbon nano-particles smaller than 10 nano-meters which show unique fluorescent and quantum properties.
Carbon range – It defines the percentage weight of carbon present in iron-based alloys like steel and cast iron, which directly dictates the material’s mechanical properties, hardness, and heat-treatment response.
Carbon ratio – It refers to the steam-to-carbon ratio in chemical processing or the carbon-to-nitrogen ratio in environmental engineering.
Carbon refractories – These refractories mainly consist of carbon. Carbon refractories are basically classified in three categories namely (i) carbon refractories, (ii) carbon containing basic refractories, and (iii) carbon containing non basic refractories. These refractories are frequently used in highly reducing environments, and their properties of high refractoriness allow them excellent thermal stability and resistance to slags. These are widely used in blast furnace hearth lining.
Carbon refractory, anthracite-coal base – It is a manufactured refractory comprised substantially of calcined anthracite coal.
Carbon refractory, graphite-base – It is a manufactured refractory comprised substantially of graphite.
Carbon refractory, metallurgical-coke-base – It is a manufactured refractory comprised substantially of metallurgical coke.
Carbon refractory, petroleum-coke-base – It is a manufactured refractory comprised substantially of calcined petroleum coke.
Carbon-reinforced plastic – It is an extremely strong and light-weight composite material made of high-strength carbon fibres embedded in a polymer resin matrix.
Carbon ring seal – It is a specialized mechanical sealing device which uses stationary rings made of carbon-graphite to control or prevent fluid and gas leakage around a rotating shaft.
Carbon restoration – It consists of replacing the carbon lost in the surface layer from previous processing by carburizing this layer substantially to the original carbon level. It is sometimes called recarburizing.
Carbon sand – It very frequently refers to a dual-media filtration material or specialized foundry material combining carbon and sand. In water treatment, it pairs a sand layer to catch dirt and sediments with an activated carbon layer to absorb chemicals, chlorine, and odours. In industrial casting, it is a non-porous carbon material used for moulds.
Carbon seal – It is a sealing mechanism consisting of a static ring of carbon that rubs against a collar on a rotating shaft, utilizing springs to maintain contact and prevent oil or air leakage. It is a specialized mechanical sealing device which uses a stationary ring or segments of carbon-graphite rubbing against a rotating metal collar or shaft to prevent fluid, oil, or air leakage.
Carbon sequestration – It is the process of storing carbon di-oxide in underground geologic formations. The carbon di-oxide is normally pressurized until it becomes a liquid, and then it is injected into porous rock formations in geologic basins.
Carbon single bond – It is a covalent chemical bond where two atoms share one pair of electrons. It is a strong sigma bond, common in alkanes like ethane.
Carbon sink – It is a natural or artificial carbon sequestration process which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere. These sinks form an important part of the natural carbon cycle.
Carbon steel – It is the steel having no specified minimum quantity for any alloying element, other than the normally accepted quantities of manganese (1.65 %), silicon (0.6 %), and copper (0.6 %), and containing only an incidental quantity of any element other than carbon, silicon, manganese, copper, sulphur, and phosphorus. Low-carbon steels contain up to 0.3 % carbon, medium-carbon steels contain from 0.3 % carbon to 0.6 % carbon, and high-carbon steels contain from 0.6 % carbon to 1 % carbon.
Carbon steel forming – It is the process of shaping carbon steel, an alloy of iron and carbon, into specific configurations and parts using mechanical force, heat, or both.
Carbon steel pipe – It is a hollow metal cylinder made from an iron and carbon alloy with a carbon content up to 2 %, designed to safely transport fluids, gases, and steam. Unlike stainless steel, it contains little to no chromium, making it more affordable but less resistant to rust.
Carbon steel strip – It is a flat-rolled ferrous metal product made from an iron-carbon alloy with up to 2 % carbon and minimal other alloying elements, shaped into thin, narrow coils or cut lengths.
Carbon strip – It is an activated carbon adsorbent material, typically derived from cotton, coal, or wood, used to adsorb volatile hydro-carbons from headspace samples during passive headspace extraction processes. The strips facilitate the adsorption of a wide range of hydro-carbons by providing a large surface area due to their porous structure. It also refers to a flat structural component made of carbon fibre reinforced polymer or a specialized carbon-based electrical contact piece used in transit systems.
Carbon substitution – It is the substitution of carbon intensive products with sustainable wood products or substitution of fossil fuel with bio-fuels.
Carbon tetra-chloride – It is also known as tetra-chloro-methane. Its chemical formula is CCl4 (one carbon atom bonded tetrahedrally to four chlorine atoms). It is a dense, non-flammable, and colourless liquid with a sweet, chloroform-like odour. It is classified as a stable, halogenated volatile organic compound (VOC) historically utilized as a powerful industrial solvent and a foundational chemical feedstock. It has boiling point of 76.7 deg C, freezing point of -23 deg C, and a high liquid density (heavier than water). It is highly stable and non-flammable under standard conditions, which made it ideal historically for industrial extraction and processing.
Carbon-to-nitrogen (C:N) ratio – It is the relative proportion by mass of organic carbon to total nitrogen in a feedstock or system, with an optimal range of 25:1 to 35:1 typically needed for efficient biological processes like anaerobic digestion and composting.
Carbon trading market – It is a decentralized market system which uses economic incentives and cap-and-trade mechanisms to reduce green=house gas (GHG) emissions. It is a framework where governments, industries, and investors buy and sell carbon emission allowances and credits. One tradable credit or allowance equals the right to emit one metric ton of carbon di-oxide (CO2) or its equivalent in other green-house gases.
Carbon triple bond – It is a covalent chemical connection where two carbon atoms share six electrons (three pairs) to form a rigid, linear structure. It is found in organic compounds known as alkynes, with acetylene (ethyne, C2H2) as the simplest compound.
Carbonyl – It is a functional group composed of a carbon atom double-bonded to an oxygen atom, with the formula C=OC=O. Carbonyl groups are common to many classes of organic compounds and are also a part of several larger functional groups. It is also an inorganic or organo-metallic coordination complex with carbon mono-oxide as a ligand (e.g. a metal carbonyl).
Carbonylation – It is a chemical reaction which introduces carbon mono-oxide (CO) into an organic or inorganic molecule to create new bonds and add a carbonyl group (C=O).
Carbonylation reaction – It is a chemical process which introduces carbon mono-oxide (CO) into an organic or inorganic molecule.
Carbonyl clusters – These are specialized molecular compounds consisting of a central core of bonded metal atoms surrounded by carbon mono-oxide (CO) ligands. In these structures, the carbon mono-oxide molecules act as ‘carbonyl’ groups which stabilize the metallic core. These clusters serve as an important bridge between bulk metals and individual atoms, making them highly valuable in advanced chemical and materials engineering.
Carbonyl compounds – These refer to chemical compounds which contain a carbonyl functional group, characterized by a carbon atom double-bonded to oxygen. These compounds, including aldehydes and ketones, are significantly present in diesel engine exhaust and can contribute to the formation of secondary organic aerosols.
Carbonyl iron process – It is a specialized method used to produce ultra-high purity (97.8 % to 99.9 %), micro-spherical elemental iron powder through the synthesis, purification, and subsequent thermal decomposition of iron pentacarbonyl [Fe(CO)5]. Adapted from the classic Mond–Langer process originally developed for nickel-refining, this process serves as a critical chemical vapour deposition (CVD) method in powder metallurgy.
Carbonyl metallurgy – It is used to manufacture products of iron, nickel, steel, and other metals. Coatings are produced by vapour plating using metal carbonyl vapours. These are metal-ligand complexes where carbon mono-oxide is bonded to individual atoms of metals .
Carbonyl oxygen – It is the oxygen atom which is double-bonded to a carbon atom (C=O) within a carbonyl group.
Carbonyl powder -It is the metal powders prepared by the thermal decomposition of a metal carbonyl compound such as nickel tetracarbonyl Ni(CO)4 or iron pentacarbonyl Fe(CO)5.
Carbonyl process – It is also known as the Mond process. It is an industrial engineering technique used to extract and refine transition metals, most notably nickel, by reacting them with carbon mono-oxide to form volatile metal carbonyl gas, which is then thermally decomposed to yield ultra-pure metal.
Carbonyl sulphide – It is a colourless, flammable gas with the chemical formula COS (or O=C=S) which typically smells like rotten eggs because of impurities. It has a linear molecule where a central carbon atom forms a double bond with an oxygen atom on one side and a double bond with a sulphur atom on the other. [It is an inorganic carbon compound and a structural hybrid / intermediate between carbon di-oxide (CO2) and carbon di-sulphide (CS2). It is the most abundant sulphur-containing gas naturally present in earth’s atmosphere, and is also found in volcanic gases, petroleum, marshes, and industrial emissions.
Carbonyl vapour – It refers to the gaseous phase of a metal carbonyl. It is a volatile, coordination complex formed when carbon mono-oxide (CO) ligands bond covalently with a transition metal. Engineers exploit these unique vapours for vapour-phase metal refining, high-purity metal powder production, and thin-film coating through chemical vapour deposition (CVD).
Carbonyl vapour metallurgy – It is a specialized extractive metallurgy process used to refine high-purity metals (predominantly nickel and iron) by reacting the metal with carbon mono-oxide gas to form a volatile metal carbonyl vapour, which is subsequently decomposed to deposit the pure metal.
Carbo-thermal reduction – It is a high-temperature industrial process where carbon acts as a reducing agent to strip oxygen away from metal oxides or other precursors, converting them into pure metals, alloys, carbides, or lower-valence compounds.
Carbo-thermic reduction – It is a process which uses carbon to strip oxygen from metal oxides at high temperatures, leaving behind pure metal and carbon mono-oxide or carbon di-oxide. It is a chemical reduction method where carbon (in forms like coal, coke, or charcoal) acts as the reducing agent.
Car bottom furnace – It is a heavy-duty industrial heating system with a movable, rail-mounted hearth (the ‘car’) which rolls outside the chamber for safe, easy loading and unloading of massive work-pieces.
Carboxylate salt – It is an ionic compound with the general formula M(RCOO)n, formed when a carboxylic acid loses its acidic hydrogen (H+) and bonds with a positive metal ion.
Carboxylation – It refers to the chemical introduction of a carboxylic acid functional group (-COOH) into a molecule, polymer, or material substrate. This process is used to alter physical properties, improve solubility, create active binding sites, or convert greenhouse gases like carbon di-oxide (CO2) into valuable chemicals.
Carboxylic acid – It is an organic acid which contains a carboxyl group (−C(=O)−OH) attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to an organyl group (e.g., alkyl, alkenyl, aryl), or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.
Carboxylic acid salt – It is an ionic compound formed when the acidic hydrogen atom in a carboxylic acid’s carboxyl group (COOH) is replaced by a metal cation or an organic cation.
Carboxy-methyl chitosan – It is an amphoteric, water-soluble polymer derivative of chitosan created by attaching carboxy-methyl groups (-CH2COOH) to its hydroxyl or amino groups.
Carburetor – It is a mechanical device in internal combustion engines which automatically mixes liquid fuel with air in the precise ratio needed for combustion.
Carburization – It is a heat treatment process which adds carbon to the surface of low-carbon steel to make the outer layer hard and wear-resistant while keeping the inside core tough.
Carburization of die steel – It is a thermo-chemical heat treatment process which diffuses carbon into the surface layer of a low-carbon or alloy steel die at high temperatures (typically 850 deg C to 950 deg C) to create a hard, wear-resistant outer case while retaining a tough, ductile core.
Carburized and hardened steels – These are low-carbon alloys which absorb carbon into their outer surface and undergo thermal quenching to create a wear-resistant exterior over a tough, shock-absorbing interior core.
Carburized bushing – It is a cylindrical metal sleeve made of low-carbon steel which has undergone a case-hardening heat treatment to create a hard, wear-resistant outer surface while keeping a tough, ductile inner core.
Carburized case – it is the hardened outer layer of a low-carbon steel component created by diffusing carbon into its surface at elevated temperatures.
Carburized gears – These are steel gears which have undergone a case-hardening heat treatment process where carbon is diffused into the outer surface layer of a low-carbon or low-alloy steel component. The resulting component features a hard, wear-resistant outer shell (the case) while maintaining a ductile, impact-absorbing core.
Carburized parts – These are low-carbon steel components which have undergone a heat-treatment process to diffuse carbon into their outer surface, creating a hard, wear-resistant exterior while leaving the inner core tough and ductile.
Carburized product – It is a low-carbon steel component which has undergone a thermo-chemical heat treatment to absorb carbon into its outer surface, creating a hard, wear-resistant exterior while keeping a tough, ductile inner core.
Carburized steel – It is low carbon steel which has undergone a case hardening process through carburization, which improves its surface hardness and wear resistance while maintaining a tough and shock-resistant core.
Carburized steel residual stress – It is the locked-in internal elastic force remaining in a component after carbon diffusion and quenching, characterized typically by high compressive stress at or just beneath the hardened case surface.
Carburizing – It is the absorption and diffusion of carbon into solid ferrous alloys by heating, to a temperature normally above Ac3 transformation temperature, in contact with a suitable carbonaceous material. It is a form of case hardening which produces a carbon gradient extending inward from the surface, enabling the surface layer to be hardened either by quenching directly from the carburizing temperature or by cooling to room temperature, then re-austenitizing and quenching. It is the process by which the surface carbon concentration of a ferrous alloy is increased by diffusion from the surrounding environment. Typically, in such a process a carbon gradient inward from the surface is formed by diffusion, enabling the surface layer to be hardened by either quenching directly from the carbonizing temperature or by cooling to room temperature, then re-austenitizing and quenching. The introduction of carbon into the surface layer is normally applied to steels having a low carbon content (case hardening steel). It can be accomplished by heating in a solid, liquid or gaseous carbon-containing medium, which at high temperatures provides a supply of carbon for absorption by the material being carburized. By controlling the temperature and time of treatment, the concentration of carbon in the surface of the steel and the depth of penetration can be varied over wide limits. In the original process of box-carburizing or pack-carburizing, the steel is heated to the necessary temperature in a solid carburizing compound, normally a mixture of hardwood charcoal and an oxide or carbonate of the alkalis or alkaline earths. Gas carburizing is finding increasing use since it gives better control over the carbon content of the case.
Carburizing and ammonia (NH3) enrichment – These are foundational thermo-chemical methods used for case hardening. Case hardening modifies the surface chemistry of a metal part, typically low-carbon steel, to create a highly wear-resistant exterior shell while keeping the interior core tough and shock-absorbent.
Carburizing and quenching – It is a heat treatment process which hardens the outer surface of low-carbon steel while keeping the inside soft and tough.
Carburizing flame – It is a gas flame which introduces carbon into some heated metals, as during a gas welding operation. A carburizing flame is a reducing flame, but a reducing flame is not necessarily a carburizing flame.
Carburizing, low temperature – Low-temperature carburizing is a surface engineering process which diffuses carbon into stainless steels or alloy steels at reduced temperatures (typically around 400 deg C to 500 deg C) to increase surface hardness and wear resistance without losing corrosion resistance.
Carburizing process – It is a heat treatment process in which steel absorbs carbon liberated when the steel is heated between 850 deg C to 950 deg C in the presence of a carbon bearing material, such as charcoal or carbon monoxide, with the intent of making the steel harder. The heated steel at this temperature has austenitic structure which has got high solubility for carbon and which is a stable structure. Depending on the amount of time and temperature, the affected area can vary in carbon content. Longer carburizing times and higher temperatures typically increase the depth of carbon diffusion. When the steel is cooled rapidly by quenching, the higher carbon content on the outer surface becomes hard through the transformation from austenite to martensite while the core remains soft and tough as a ferritic and / or pearlitic micro-structure.
Carburizing-quenching process – It is a thermochemical surface-hardening treatment which infuses carbon into the outer layer of low-carbon steel at high temperatures and then cools it rapidly to create a hard, wear-resistant surface while keeping the inner core tough and ductile.
Carburizing steel – Carburizing steels normally have base carbon contents of around 0.2 %, with the carbon content of the carburized layer normally being controlled in the range of 0.8 % to 1 %. However, surface carbon is frequently limited to 0.9 % since too high a carbon content can result in retained austenite and brittle martensite, Carburized steel consists of a composite material, where the carburized surface is hard but the unaffected core is softer and ductile. Compressive residual stresses are formed in the surface layer upon quenching from the carburizing temperature. The combination of high hardness and compressive stresses results in high fatigue strength, wear resistance and toughness.
Carcass – The reinforcement found on the inside of a conveyor belt is normally referred to as the carcass or carcase. In a sense, the carcass is the heart of the conveyor belt since it (i) provides the tensile strength necessary to move the loaded belt, (ii) absorbs the impact of the impinging material being loaded onto the conveyor belt, (iii) provides the bulk and lateral stiffness needed for the load support, and (iv) provides adequate strength for proper bolt holding and / or fastener holding.
Carcass compliance – It refers to the ability of the tyre’s carcass to deform under load, which integrates with the contact patch slip properties and influences the tyre’s dynamic behaviour.
Card – It normally refers to a flat, card-shaped component or module which holds electronic circuits, data storage, or processing power. Card is a removable or modular flat board which holds electronic components like microchips, resistors, and connectors to perform specific functions.
Cardan joint – It is a mechanical coupling used to transmit torque and rotational motion between two rigid shafts whose axes are inclined at an angle to each other. It is mainly composed of a cross with four trunnions and needle bearings, allowing for diverse angular movements during operation. Also known as a universal joint or U-joint, it allows power transmission even when connected shafts are out of alignment.
Carded sliver – It is a twist-less rope of disentangled fibres which have been straightened and oriented in a common direction during the carding process, held together by inter-fibre friction and prepared for subsequent processing steps.
Cardinality – It is the number of distinct elements in a finite set, denoted by | S |. For example, in the set {m, i, s, p}, the cardinality is 4, regardless of repetitions of elements. It means the number of unique or distinct data values in a set, column, or data-base management system (DBMS).
Cardinal points – These are a set of six reference points on the optical axis of a rotationally symmetric, thick lens or optical system that simplify how engineers calculate image formation.
Car furnace – It is a batch-type furnace using a car on rails to enter and leave the furnace area. Car furnaces are used for lower stress relieving ranges.
Cargo – It is the physical goods, merchandise, or materials transported through commercial vehicles, aircraft, trains, or ships, excluding passengers and crew.
Cargo handling – It is the systematic design, operation, and optimization of mechanical and automated processes used to safely load, stow, transfer, and unload freight between transport vehicles, vessels, and storage facilities.
Car hearth furnaces – These furnaces have a movable hearth with steel wheels on rails. The load is placed on the car hearth, moved into and heated in the furnace and removed from the furnace on the car hearth. The car hearth is then unloaded. Cooling is done on the car hearth either in the furnace or outside before unloading. This type of furnace is used mainly for heating heavy or bulky loads, or short runs of assorted sizes and shapes. The furnace door can be affixed to the car.
Carman-Kozeny equation – Kozeny-Carman equation is a mathematical model used to describe the permeability of porous media, incorporating a fitting constant which relates to pore shape and constriction factors, and serves as a key parameter for analyzing sedimentological attributes and flow zones in reservoir development.
Carman-Kozeny relationship – Kozeny–Carman relationship is a model used to describe the relationship between porosity and permeability in porous media, developed under the assumption that the media can be represented by uniform, straight capillary tubes.
Carnot battery – It is an energy storage system which stores electricity as thermal energy (heat or cold) and converts it back into electricity when needed. It is also known as power-to-heat-to-power (P2H2P) storage.
Carnot cycle – It is an ideal, theoretical thermodynamic cycle which sets the maximum possible efficiency for any heat engine. It shows how heat changes into work using a reversible process between a hot and a cold temperature reservoir. Real engines cannot reach this efficiency since real-world processes involve friction and energy losses.
Carnot cycle efficiency – It is the highest possible theoretical efficiency for any heat engine operating between two specific thermal reservoirs.
Carnot efficiency – It is the highest possible theoretical efficiency a heat engine can achieve when operating between two specific temperature reservoirs.
Carnot engine – It is a theoretical, ideal heat engine which operates on a reversible thermodynamic cycle to establish the maximum possible efficiency for converting heat into mechanical work between two fixed temperatures. It functions as a benchmark or conceptual upper limit in engineering and thermodynamics, meaning no real-world engine can exceed its efficiency because of the inescapable losses like friction and thermal gradients.
Carnot factor – It is the maximum theoretical efficiency or exergy fraction available from heat transfer at a specific temperature (T) relative to a lower reference environment temperature (To).
Carnot limit – It is the absolute maximum theoretical efficiency any heat engine can achieve when converting heat energy into useful work between two specific temperatures.
Carnot refrigerator – It is an idealized, fully reversible refrigeration system which operates between two thermal reservoirs to achieve the maximum possible coefficient of performance (COP). It serves as a standard upper limit for evaluating the performance of real-world refrigeration and vapour-compression cycles.
Carpet plot – It is a two-dimensional graphical tool used to display the interactions between multiple independent variables and dependent variables without needing a complex 3D or contour surface.
Carriage And Insurance Paid To (CIP) – ‘Carriage and Insurance Paid to’ means that the seller delivers the goods to the carrier or another person nominated by the seller at an agreed place (if any such place is agreed between parties) and that the seller must contract for and pay the costs of carriage necessary to bring the goods to the named place of destination. ‘The seller also contracts for insurance cover against the buyer’s risk of loss of or damage to the goods during the carriage. The buyer should note that under CIP the seller is required to obtain insurance only on minimum cover. Should the buyer wish to have more insurance protection, it will need either to agree as much expressly with the seller or to make its own extra insurance arrangements’.
Carriage Paid To (CPT) – ‘Carriage Paid To’ means that the seller delivers the goods to the carrier or another person nominated by the seller at an agreed place (if any such place is agreed between parties) and that the seller must contract for and pay the costs of carriage necessary to bring the goods to the named place of destination.
Carrier – it is a substance, device, or signal which supports, transports, or holds a functional component. In emission spectrochemical analysis, it is a material added to a sample to facilitate its controlled vapourization into the analytical gap.
Carrier absorption – It is a semi-conductor process where free charge carriers (electrons or holes) absorb photons and transition between energy states within the same electronic band.
Carrier agent – It is a reactive chemical species or substance which reversibly binds to a specific permeating component on one side of a membrane to facilitate its selective, assisted transport across to the other side.
Carrier aggregation – It is a telecommunications technique which combines multiple distinct frequency channels, called component carriers, into a single wide virtual channel to increase user bandwidth and data throughput.
Carrier board – It is a custom printed circuit board which connects, powers, and provides input / output (I/O) interfaces for a computer-on-module (COM) or system-on-module (SOM). The carrier board acts as the ‘body’ linking it to external peripherals like cameras, sensors, and Ethernet ports.
Carrier chain conveyor – Carrier chain conveyor consists of one or more number of endless chains to which can be attached one of the many different attachments for the purpose of carrying unit materials or objects. In several cases, the materials are conveyed while being directly in contact with the chain / chains. These conveyors have a broad application in practically all the fabricating and the processing industries. Different designs of attachments are used for different types of materials. Carrier chain conveyors are normally classified into two basic types namely (i) rolling type, and (ii) sliding type.
Carrier combination – It is the specific configuration and pairing of multiple frequency bands and individual radio frequency carriers used simultaneously to increase data throughput and network capacity.
Carrier complex – It is an ion bound to a transport molecule inside a hydrophobic (water-repelling) membrane, which allows the ion to move across the barrier.
Carrier concentration – It is the number of mobile charge carriers (free electrons or holes) per unit volume in a material, measured in inverse cubic centimeters or inverse cubic meters. It dictates how well a material conducts electricity and forms the foundation for designing electronic devices like diodes and transistors.
Carrier control – It alters properties of a wave (like light or radio frequency) to carry digital information.
Carrier density – It is the number of free charge carriers, such as electrons or holes, per unit volume in a material. It is measured in inverse cubic meters or inverse cubic centimeters.
Carrier diffusion length – It is the average distance which an excess charge carrier (electron or hole) travels in a semi-conductor from the point of generation or injection until it undergoes charge recombination.
Carrier effect – It refers to the hot carrier effect, where charge carriers (electrons or holes) gain exceptionally high kinetic energy from strong electric fields inside a miniaturized device. It, also known as the support or substrate effect, refers to the influence of the catalyst support material on the catalytic performance of precious metal catalysts for water splitting. The choice of support material can considerably impact the electronic structure, surface properties, and overall efficiency of the catalyst in driving water splitting reactions. One key aspect of the carrier effect is the interaction between the precious metal catalyst and the support material. The support can alter the electronic properties of the catalyst, affecting its ability to adsorb reactant species, facilitate charge transfer, and participate in catalytic reactions.
Carrier fluid – It is a base liquid or gas used to dissolve, suspend, or transport another active material, such as a lubricant, heat-transfer particle, or chemical coating, through a system or process.
Carrier frequency – It refers to the frequency used in GPS (global positioning system) carrier phase measurements, which is considerably higher than the code frequency transmitted by satellites. It allows for higher resolution in measurements, but needs corrections for factors such as orbital data and atmospheric conditions.
Carrier frequency offset – It refers to the discrepancy in frequency between the transmitted signal and the received signal in communication systems like OFDMA (orthogonal frequency-division multiple access), impacting decoder performance. It is the frequency difference between a transmitted radio signal and the local oscillator inside a receiver. It is one of several non-ideal conditions which can affect in base-band receiver design.
Carrier gas – In thermal spraying, the gas used to carry the powdered materials from the powder feeder or hopper to the gun.
Carrier injection level – It is the ratio of excess minority charge carriers introduced into a semiconductor material to the equilibrium density of majority carriers. It refers to the density of excess charge carriers introduced into a semi-conductor material, which influences recombination processes and impacts parameters such as effective lifetime and saturation current density. This concept is particularly relevant in the context of emitter saturation current densities in silicon solar cells.
Carrier leakage – It is the unwanted appearance of an unmodulated local oscillator or carrier frequency at the output of a radio frequency (RF) transmitter.
Carrier lifetime – It is the average time an excess minority charge carrier (an electron or a hole) survives in a semiconductor before it recombines and is neutralized.
Carrier liquid (- It is the base solvent or circulating fluid used to dissolve, transport, suspend, or transfer another substance (an analyte, active ingredient, or solid particle).
Carrier localization effect – It describes how charge carriers (electrons or holes) become trapped or confined within restricted spatial regions because of the potential energy fluctuations in a material.
Carrier mobility – It is a physical property which measures how fast free electrons and holes move through a semi-conductor or metal when an electric field is applied.
Carrier operation – It broadly refers to the systematic process of transporting materials, data, signals, or charge carriers within a physical, chemical, or electronic system.
Carrier phase – it is the measurement of the fractional cycle of a received radio frequency or satellite carrier wave relative to a reference signal generated by a receiver.
Carrier pipe – It is the inner tube in an engineering or utility system which directly holds and transports the actual fluid, gas, or product from one place to another.
Carrier population – It is the total collection of mobile charge carriers, such as free electrons and holes, which participate in electrical conduction within a semi-conductor or other conductive material.
Carrier sense – It is a device which listens to the communication channel (the radio frequency or cable) to check if another device is currently transmitting.
Carrier sense multiple access – It is a media access control (MAC) protocol where a device listens to a shared network channel to check if it is free before transmitting data.
Carrier sense multiple access with collision avoidance – It is a network protocol used at the data link layer to prevent data collisions on shared communication channels, mainly in wireless networks like Wi-Fi.
Carrier signal – It is a high-frequency wave-form, normally a sine wave, which is modified to transport information-bearing messages across a communication channel.
Carrier-to-interference (C/I) ratio – It is the proportion of desired signal power to unwanted interfering signal power in a communication channel. It measures the wanted carrier power (C) against the total power of interfering signals (I) from other transmitters or co-channel sources.
Carrier transmission – It is a broadband communication method where an information signal modifies a higher-frequency wave (the carrier) to travel efficiently over a transmission channel.
Carrier vessel – It is a specialized merchant ship designed to transport unpackaged dry or liquid bulk materials in large quantities.
Carrier water – It refers to the water transported through hydrophilic (water-attracting) structures or porous materials to support processes like solar desalination and evaporation. It moves bulk water efficiently toward photothermal (light-to-heat) layers.
Carrier wave – It is a steady, high-frequency sinusoidal wave-form which is modulated with a message signal to transport information over a transmission medium.
Carrollite – It is a metallic sulphide mineral with the chemical formula CuCo2S4₄serving as a critical ore for cobalt extraction. It frequently incorporates nickel (Ni) in solid solution [Cu(Co,Ni)2S4]. As the global transition to green energy and electric vehicles accelerates, carrollite has transitioned from a rare collector’s mineral to an economically significant mineral asset. Its crystal system is isometric (cubic), specifically belonging to the thio-spinel group (Fd3m space group). Its density is in the range of 4.5 grams per cubic centimeter to 4.8 grams per cubic centimeter (measured). It is highly relevant for gravity separation processing. Its mechanical hardness ranges from 4.5 to 5.5 on the Mohs scale. Its Vickers hardness (VHN100) ranges from 507 kilograms per square millimeter to 586 kilograms per square millimeter. It is brittle with an uneven to conchoidal fracture, dictating specific energy needs during grinding and milling. It displays metallic luster, It is opaque, and shows a super-conductivity transition at low temperatures.
Carryback – It consists of the residual material persistently adhering to the conveyor belt, making its way back along the return side. It necessitates the implementation of cleaning and removal mechanisms to maintain optimal conveyor functionality.
Carry cover – It is the material carrying side of a conveyor belt. In most cases thicker than the bottom cover.
Carrying capacity – It is essentially a design concept, based on the number of use units (people, products, dusts, moisture etc.) which can physically be accommodated in a certain area or volume.
Carrying channel – It is a main load-bearing structural member used to distribute weight and provide rigid framework stability. It is most prominently utilized in lightweight steel framing and suspended ceiling systems.
Carrying fluid – It is a gas or liquid used to transport other substances, particles, or thermal energy through a system. Its main purpose is to act as the medium of conveyance rather than being the final product itself.
Carrying operation – It refers to scheduled or on-demand transport and logistics processes, or the mechanical capability of a structure, vehicle, or fluid to support and move loads.
Carrying pipe – It is the main inner tube which safely transports liquids, gases, or cables from a source to a destination.
Carry-over – It is the chemical solids and liquid entrained with the steam from a boiler.
Cartesian components – These refer to the individual elements of a tensor represented in a Cartesian coordinate system, which can be used to describe different properties such as isotropic and anisotropic interactions.
Cartesian coordinate frame – It is a system consisting of an orthonormal basis of vectors and a point called the origin, where the basis satisfies the right-handedness condition and the orthogonality relations.
Cartesian coordinates – These are numbers which show the exact position of a point on a flat surface or in space using perpendicular lines. This system uses a grid with intersecting reference lines.
Cartesian coordinate system – It is a coordinate system in which the position of a point in a plane is determined by its distance and direction from the ‘x’ and ‘y’ axis, which are perpendicular to each other. In three dimensions a Cartesian coordinate system is defined by the ‘x’, ‘y’, and ‘z’ axes.
Cartesian grid – It is a coordinate system which uses two perpendicular number lines intersecting at a zero point to map the exact location of points on a flat surface.
Cartesian robot – It is an industrial machine which moves in straight lines along three perpendicular axes (‘x’, ‘y’, and ‘z’) based on the Cartesian coordinate system. Also known as linear robots or gantry robots, they do not use rotating or sweeping arms. Instead, they operate on a rigid frame or rail system, moving left-right, forward-backward, and up-down.
Cartesian velocity component – It is the rate of change of an object’s position along a single coordinate axis (‘x’, ‘y’, and ‘z’) within a Cartesian coordinate system.
Cartridge brass – It is a ‘straight’ 70 % copper / 30 % zinc brass with very good cold forming and deep-drawing properties. It is so called since it has been originally used for deep-draw cartridge cases. It now has a wide range of industrial applications, particularly if severe deformation, such as spinning or flanging, is involved. Arsenical Brass can be preferred because of its superior corrosion resistance.
Cartographic data – It refers to spatial information represented in maps, which allows users to understand and navigate geographical areas, while also encompassing uncertainties linked to data production and observation processes.
Car-type conveyor – This type of conveyor consists of a series of small platform cars, propelled by an endless chain, running on a closed track. Car-type conveyors can have vertical run-arounds over-sprockets having horizontal axis. However, more frequently they are designed with horizontal run-arounds (carousels) over sprockets (or sheaves for rope drive) with vertical axis. This type of conveyor is also called a carousel conveyor or a pallet-type conveyor.
Cascade connection – It is an arrangement of multiple sub-systems or devices in a series where the output signal of one stage becomes the input to the next.
Cascade control – It uses two nested feed-back loops. The main (master) controller sets the goal for a secondary (slave) controller to stabilize a main process faster and better.
Cascade control system – It is an advanced control set-up which uses two or more nested feed-back loops, where the output of the main (master) controller sets the target value (set point) for the secondary (slave) controller.
Cascaded cycle – It is a multi-stage cooling system which uses two or more independent vapour-compression loops connected in series by a shared heat exchanger.
Cascade design – It is a system or process structured in sequential, connected stages where the output of one stage automatically becomes the input for the next.
Cascaded H-bridge inverter – It is a type of electronic circuit which converts direct current (DC) into alternating current (AC) by connecting multiple single-phase full-bridge (H-bridge) power units in series.
Cascade diagram – It typically refers to a cascade control system block diagram, which shows a set-up with two nested feedback loops where one controller adjusts the setpoint of another to improve system stability.
Cascaded loop – It is a control set-up where two or more feedback loops are nested together, with the output of the outer (main) loop setting the target value (set-point) for the inner (secondary) loop.
Cascaded stages – These stages mean a set-up where the output of one device or process becomes the input for the next one in a sequence.
Cascaded system – It is an arrangement where devices, circuits, or control loops are connected in a series or hierarchical sequence, such that the output of one stage directly acts as the input or set-point for the next.
Cascade factor – It typically refers to an indicator or multiplier used to measure resource efficiency, multi-stage processing effectiveness, or sequential failure rates as a process flows through successive steps.
Cascade form – It is a multi-stage set-up where several identical or progressive units process material or signals sequentially, such as in distillation columns, isotope separation, or cascade control systems. It is also a method of realizing a complex transfer function H(z) by factoring it into a product of simpler, lower-order subsystems (like first-order or second-order biquad sections). ‘H(z) = H1(z).H2(z)…….Hn(z)’. Cascade form is also known as a classifier cascade, it applies a sequence of increasingly complex stages to filter out non-target data quickly.
Cascade impactor – It is a multi-stage sampling device used to measure the aerodynamic particle size distribution of aerosols and airborne particulates.
Cascade refrigeration cycle – It is a multi-stage cooling system which uses two or more separate vapour-compression loops linked by an intermediate heat exchanger to reach very low temperatures.
Cascading – It means connecting devices, processes, or control loops in a series where the output of one stage becomes the input of the next.
Cascading bed motion – The cascading bed motion in a rotary kiln occurs because of the clustering of several particles in the upper zone under the action of the increased rotation speed. When a condition in which the height of the leading edge (shear wedge) of the material rises above the bed surface is reached then the particles cascade or shower down on the free surface. This motion is associated with the high particle-to-heat transfer fluid exposure.
Cascading effects – These refer to the propagation of an accident within an industrial cluster, where an incident in one facility can trigger subsequent incidents in neighbouring installations because of the inter-dependence of hazardous materials and processes, potentially leading to widespread escalation of the main accident.
Cascading failures – These refer to a series of sequential disruptions within power systems which propagate and lead to widespread black-outs, frequently triggered by initial failures or natural disasters. These failures can escalate because of the unnormal conditions, necessitating their consideration in the development of resilient strategies against such events.
Cascading menu – It is a hierarchical user interface control where selecting an item on a parent menu opens a secondary submenu off to the side.
Cascading protection – It is also known as back-up protection. It is a strategy where a powerful upstream circuit breaker uses its current-limiting ability to protect weaker, lower-rated, and more cost-effective circuit breakers downstream during extreme short-circuit faults.
Cascade phase -It refers to a sequence of steps where the output of one stage serves as the direct input for the next. This methodology is widely used to break down complex systems, refine materials, or step-down high-powered forces safely and efficiently.
Cascade process – It is a multi-step operation where the output or enriched fraction of one stage feeds directly into the next stage to achieve a result which a single step cannot efficiently accomplish alone.
Cascade system – It is a set-up where two or more devices, loops, or sub-systems are connected in a series or hierarchical arrangement, where the output or action of one stage directly influences or becomes the input for the next.
Cascade theory – It very frequently refers to cascade control, a nested feedback architecture where a main (master) controller adjusts the set-point of a secondary (slave) inner loop to reject disturbances faster and more accurately.
Cascode amplifier – It is a two-stage electronic circuit which stacks a common-emitter (or common-source) input stage in series with a common-base (or common-gate) output stage. In this configuration, the first transistor handles the input voltage-to-current conversion, while the second transistor acts as a current buffer and shields the input stage from output variations.
Case – In heat treating, it is that portion of a ferrous alloy, extending inward from the surface, whose composition has been altered during case hardening. Typically, it is considered to be the portion of an alloy (i) whose composition has been measurably altered from the original composition, (ii) which appears light when etched, or (iii) which has a higher hardness value than the core.
Case carburizing – It is a thermo-chemical heat treatment process which diffuses carbon into the surface layer of a low-carbon steel part at high temperatures to create a hard, wear-resistant outer case while keeping a tough, ductile inner core.
Case crushing – It is a term used for denoting longitudinal gouges arising from fracture in case-hardened gears.
Case database – It is the main knowledge base of a case-based reasoning (CBR) system, which stores accumulated cases that can be retrieved for reasoning and learning. It needs maintenance through the addition, deletion, and updating of cases to manage redundancy and optimize retrieval efficiency. Case database is also central repository which is the core data hub within a computer-aided software engineering environment that stores all project artifacts, models, and metadata.
Case depth – It is the thickness of the hardened outer layer (the case) on a metal component relative to its softer, tougher inner core.
Cased hole section – It is the portion of a well-bore lined with steel pipe (casing) and filled with cement in the annular space between the pipe and the rock formation.
CASE (computer-aided software engineering) framework – It refers to the architecture and integration structure underlying computer-aided software engineering (CASE) tools, which automate and support the software development life cycle (SDLC).
Case hardness – It is the measure of resistance to indentation and wear on the outer surface (the case) of a metal component which has undergone a case hardening treatment.
Case hardening – It is a generic term covering several processes applicable to steel which change the chemical composition of the surface layer by absorption of carbon, nitrogen, or a mixture of the two and, by diffusion, create a concentration gradient. The processes normally used are carburizing and quench hardening, cyaniding, nitriding, and carbonitriding.
Case micro-structure – It refers to the microscopic arrangement of phases, grains, and defects in the hardened outer layer (the case) of a metal component produced through surface-hardening processes like carburizing, nitriding, or induction hardening.
CASE (chemically assisted surface engineering) process – Chemically assisted surface engineering (CASE) process can reduce the relative finishing time and costs, after shot peening, and provide a surface which, in addition to having the compressive stresses from the shot peening, can have ‘Rsk’ (skewness) value of as little as -1.1. Very significant increases in surface contact fatigue (pitting) life have been observed. CASE (chemically assisted surface engineering) covers a two-stage process. It needs that the gears are properly shot peened, followed by chemically assisted super-finishing. Very different surface profiles can be described using nearly the identical ‘Ra’ (roughness average) values. The aim of chemically assisted surface engineering process, however, is to smooth the spherical edges
Cases – These are units of analysis in one’s study. In logistic regression, however, the term also refers to the units of analysis who have experienced the event of interest.
Case-specific technology limits – It is also known as end-of-pipe limits or sector-specific technology limits. It is a subcategory of technology-based limits. It is a limit based on existing performance, or performance from similar facilities. Unlike a sector-specific technology limit, it is not a published limit. It is derived using best professional judgment.
Case study – A case study involves extensive and in-depth formal research into an area of an organization, a situation, or an event. Case studies typically result in formal reports The case studies investigate important, singular, or locally representative cases which contribute to the advancement of knowledge.
Case study building – It is a representative structure selected for detailed evaluation, possessing geometric traits and materials typical of a broader group of similar buildings.
Case thickness – It is also called case depth. It is the thickness of the hardened outer surface layer of a metal component produced by a surface-hardening process like carburizing, nitriding, or induction hardening.
Cash flow – It refers to payments made into or out of an organization, project, or financial product. It can also refer more specifically to a real or virtual movement of money.
Cash flow analysis – It is a method to calculate the economic result of a project year by year by assessing cash flow over its economic lifetime, incorporating factors such as power production, prices, loans, interest rates, and maintenance costs. It utilizes spreadsheet software to present the results in diagrams and tables which show cash flow, revenues, capital costs, and surplus.
Cash flow pattern – It is the organized behavioural structure or sequence of cash inflows (receipts / revenues) and outflows (disbursements / costs) occurring over the economic life-time of a project.
Cash register – It is a mechanical or electronic device used to calculate, record, and secure financial sales transactions, featuring a lockable cash drawer and a mechanism for printing receipts. A cash register integrates several mechanical, electrical, and computational components.
Casimir effect – It is a phenomenon where two uncharged, perfectly conducting plates placed in a vacuum attract each other because of the quantum fluctuations, producing a measurable force at very small separations, particularly below a micrometer.
Casimir force – It is an attractive force which arises between two closely spaced mirrors because of the disturbance of the zero-point electro-magnetic field, resulting in a lower energy density in the gap between them. This force considerably affects nano-scale mechanical devices at separations of around 10 nano-meters.
Casing – It is a covering of sheets of metal or other material such as fire-resistant composition board used to enclose all or a portion of a steam generating unit.
Casing annulus – It is the ring-shaped space or void located between two concentric cylindrical objects in a wellbore, such as between the outer well-bore wall and the casing, or between an inner production string and an outer casing.
Casing hanger – It is a mechanical device in a well-head that supports the weight of a casing string and seals the space between the casing and the well-head housing.
Casing-head pressure – It is the gas or fluid pressure measured at the surface inside the annular space (the gap) between the outer casing and the inner production tubing of an oil or gas well.
Casing pipe – It is a large-diameter protective outer tube used to line boreholes, stabilize weak or loose soil, and shield inner carrier lines from external pressure.
Casing pressure – It is the fluid or gas pressure measured within the annulus, the space between the casing and the production tubing or another casing string, at the well-head of a well.
Casing shoe – It is a hardened steel or concrete-profiled cylindrical fitting attached to the bottom-most joint of a casing string.
Casing spool – It is a flanged well-head component installed above the base casing head to support intermediate or production casing strings.
Casing string – It is a connected series of steel pipes lowered into a well-bore and normally cemented in place to stabilize the well and isolate different formations.
Casing treatment – It is a design method used in compressors and gas turbine engines to improve stability and prevent stall by modifying the inner wall surrounding the rotor tips.
CAS number – It is a unique numerical identifier assigned by the Chemical Abstracts Service (CAS) to every chemical substance described in the open scientific literature, including more than 182 million organic and inorganic compounds, minerals, isotopes, alloys, polymers, and mixtures, as well as so-called ‘UVCBs’ (substances of unknown or variable composition, complex reaction products, or biological origin). CAS numbers are an internationally recognized standard used by scientists, industries, and regulatory bodies.
CAS-OB process – It is a ladle treatment process in secondary metallurgy which is used for the heating of steel through chemical means. The abbreviation CAS-OB stands for ‘composition adjustment by sealed argon bubbling – oxygen blowing’. During the CAS-OB process, the most important functions are the adjustment of the temperature to an optimum level and the accurate addition of alloying elements. The purpose of the heating is to ensure sufficient temperature of the liquid steel when it is sent to the continuous casting machine. The CAS-OB process belongs among the processes which operate at the atmospheric pressure. The CAS-OB process is designed for homogenization and control of the composition and temperature of steel. It is a ladle treatment process which is designed for heating and alloying of liquid steel.
Cassegrain – It refers to a type of antenna which utilizes a parabolic main reflector and a hyperbolic sub-reflector to improve gain, allowing signals to be directed to a feed located at or in front of the main reflector’s vertex. This configuration improves accessibility to feed electronics and reduces cable loss compared to prime focus feeds, although it can introduce alignment challenges and blockage issues.
Cassegrain reflector – It is an optical system which uses a two-mirror configuration to fold a long focal length into a compact physical space. This design is widely used in telescopes, satellite communications, and radar antennas.
Cassette tape – It is an enclosed analog magnetic recording format which stores audio or data on a thin plastic strip coated with ferro-magnetic material.
Cassie-Baxter Equation – It is a mathematical model which predicts the apparent contact angle of a liquid droplet resting on a rough, porous, or chemically heterogeneous surface.
Cassiterite – It is a tin oxide mineral (SnO2) which serves as the principal source of tin metal, containing around 78.6 % tin. It typically appears in colours such as black, brownish-black, and reddish-brown, and is formed through hydrothermal processes, occurring in veins, alluvial, and placer deposits. It is normally opaque, but it is translucent in thin crystals. Its lustre and multiple crystal faces produce a desirable gem.
CASS test – CASS (copper-accelerated salt-spray) test is an accelerated corrosion test used to evaluate the durability and resistance of metallic materials and surface coatings under severe environmental conditions.
CASS testing – It is normally used for testing decorative electro-deposited coatings of nickel / chromium and copper / nickel / chromium. Applications for this test method include specification acceptance, manufacturing control of product or process, simulated service evaluations, and research and development (R&D) of new coating technologies.
CASS test method – It is an aggressive accelerated corrosion test used to determine corrosion resistance of different aluminum alloys and for testing chromium plating on zinc and steel die castings.
Cast A-359 metal matrix composites – These composites use an A359 aluminum alloy base reinforced with ceramic particles like silicon carbide (SiC) or aluminum oxide (Al2O3) to improve strength and wear resistance.
Castable – In casting, it is a combination of refractory grain and suitable bonding agent which, after the addition of a proper liquid, is normally poured into place to form a refractory shape or structure which becomes rigid because of chemical action. Castable materials are capable of being formed into a shape or structure (typically by pouring after the addition of a suitable liquid) and then becoming rigid because of chemical reaction.
Castable ceramic fibre – It is also called castable refractory ceramic fibre. It is ceramic fibre with inorganic and / or organic binder which can be cast.
Castable refractories – These are monolithic refractories which consist of a group of products which with the addition of water, are cast into place. Castable refractories are supplied dry, mixed onsite and installed behind shuttering or cast in a mould to form the required shape.
Castability – It is a complex combination of liquid-metal properties and solidification characteristics which promotes accurate and sound final castings. It is also the relative ease with which a molten metal flows through a mould or casting die.
Cast alloy – It is a metal mixture melted down and poured into a mould to cool and harden into a specific shape. This process makes it easy and cheap to build complex parts like engine blocks or pipes without cutting them from solid blocks.
Cast aluminum alloys – These are metal mixtures made mainly of aluminum and other elements like silicon, copper, or magnesium which are melted and poured into moulds to form complex shapes. Cast aluminum alloys are categorized into several systems based on their alloying elements, including aluminum-silicon, aluminum-copper, aluminum-magnesium, and aluminum-zinc, and are used in different applications because of their casting characteristics and mechanical properties.
Cast-and-wrought superalloys – These are high-performance metal mixtures initially formed by melting and casting into an intermediate shape (like an ingot or billet), then mechanically deformed (such as forged, rolled, or extruded) at high temperatures to achieve their final microstructure and form.
Cast carbon steel – It is a specialized type of steel alloy made by pouring molten metal having iron and carbon, with a carbon content typically up to 2 %, directly into a mould to form a specific shape.
Cast cobalt-base heat-resistant alloys – These are metallic materials using cobalt as the main matrix element, shaped through pouring into moulds (casting), and engineered to maintain structural strength, oxidation resistance, and thermal fatigue stability at extreme elevated temperatures.
Cast condition – It refers to the state of cast iron which is used as-is immediately after the casting process, before any heat treatment is applied. It is characterized by the alloy’s composition and the resulting matrix structure that influences its mechanical properties.
Cast corrosion-resistant nickel alloys – These are specialized metal components shaped through liquid pouring which use nickel as their main base element to resist severe chemical attack, oxidation, and environmental breakdown.
Cast dies – These are dies produced by casting process. The principal advantage of cast dies is the savings in die making costs which can be achieved by minimizing the quantity of machining necessary for die fabrication. Normally, only a polishing operation is necessary to finish cast dies. Another advantage of cast dies is improved micro-structure over wrought dies, with smaller, more evenly dispersed carbides and less grain-boundary segregation of carbides. Non-uniform carbide distribution in some wrought tool steels can lead to early wear (in areas lean in carbides) and premature heat checking (in areas rich in carbides). A further advantage provided by cast dies is more equi-axed grain structure than wrought products formed by rolling or forging. Grain direction in wrought alloys improves properties in some directions (parallel to the grain), but results in reduced properties transverse to the grain direction. Castings have no grain directionality and hence display more uniform properties. There are also some disadvantages in using cast dies. Sections around the die cavity are to be of a fairly uniform thickness to avoid excessive residual stresses in the casting of the die. Also, because of the lower strength of cast dies, the sections around the die cavity are to be relatively thick. The dies can hence become rather massive. Inspection can be difficult. Radiographic inspection is virtually the only method available to test for soundness. Large cast dies are used when it is not convenient to make the die as a forging either because of its mass or because of a lack of capacity to produce a forging of the needed size.
Cast DRA (discontinuously reinforced aluminum) alloys – These are metal-matrix composites made by pouring molten aluminum combined with discrete ceramic particles, whiskers, or short fibres into moulds. These alloys consist of an aluminum alloy base (matrix) mixed with 10 % to 30 % non-metallic reinforcements like silicon carbide (SiC) or aluminum oxide (Al2O3).
Castellated beam – It is a beam style where an I-beam is subjected to a longitudinal cut along its web following a specific pattern in order to divide it, and reassemble the beam with a deeper web by taking advantage of the cutting pattern.
Caster – It consists of wheels strategically mounted in a fork, either rigid or swivel, providing support and portability to conveyors. Caster term is also used for continuous casting machine. Caster is also a person who carries out the casting operation.
Cast film – It is a film made by depositing a layer of liquid plastic onto a surface and stabilizing this form by the evaporation of solvent, by fusing after deposition, or by allowing a melt to cool. Cast films are normally made from solutions or dispersions.
Cast film extrusion – It is a manufacturing process where melted plastic resin is pushed through a flat slot die to create a thin, continuous flat sheet which is immediately cooled on a chilled roller. In polymer processing, this method is widely used for high-speed production of flexible plastic films with precise thickness control and high optical clarity.
Cast, heat, melt – These terms are used interchangeably to refer to the product of a single melting furnace charge. It is sometimes the furnace contents which are tapped into one or more ladles when the product of each ladle can be called a separate cast. It is always assumed that the chemical composition of an entire cast is uniform. This is described as the ‘cast or heat analysis’ on a test certificate of conformity etc.
Cast heat-resistant nickel alloys – These are specialized metal mixtures shaped by pouring molten liquid into moulds, engineered to maintain structural integrity, strength, and resistance to oxidation or creep at high operating temperatures.
Cast house – This is the area around the blast furnace at the tap hole level. It contains equipment for opening and closing of tap-hole and trough and runners for flow of hot metal and liquid slag.
Cast housing – It is a rigid, hollow metal enclosure made by pouring molten material into a mould. It consists of a single, seamless shell designed to cover, protect, and support internal mechanical parts or contain liquids. Common materials are gray iron, ductile iron, and aluminum alloys.
Castigliano’s theorem – It is a structural mechanics method used to find the displacement or rotation of a linear-elastic structure by taking the partial derivative of its total strain energy. This method makes complex structural analysis easier, especially for finding deflections or solving statically indeterminate problems without long equilibrium equations.
Casting – It is the metal object cast to the required shape by pouring or injecting liquid metal into a mould, as distinct from one shaped by a mechanical process. It is also pouring molten metal into a mould for producing an object of desired shape.
Casting alloys – These alloys refer to a category of materials used in casting processes, which mainly include cast irons, cast steels, and alloys based on aluminum, zinc, magnesium, and copper. These alloys are characterized by their processing parameters, which affect properties such as strength and freezing range, with distinctions made between ‘skin freezers’ and ‘mushy freezers’ based on their solidification behaviour.
Casting and solidification modelling – It is the computerized simulation of pouring liquid metal into a mould and watching it cool, freeze, and form a solid shape.
Casting and solidification processing – It is a manufacturing method where liquid material, normally molten metal, is poured into a hollow mould cavity and allowed to cool and harden into a specific three-dimensional shape.
Casting bed – It is a rigid, long, and levelled flat surface or foundation used to manufacture pre-cast or pre-stressed concrete structural elements, such as beams, girders, and hollow-core slabs.
Casting conditions – These conditions refer to the different practical factors and variables which affect the quality of castings during the manufacturing process, including mould dimensions, cooling rates, and the ability of the mould to resist deformation. Effective control of these conditions is necessary to ensure the soundness and reproducibility of the castings produced.
Casting cooling – It is the process in which the temperature of a casting drops gradually after it is formed. It includes the cooling of the casting in the mould, as well as the secondary cooling of the casting after removal from the mould.
Casting cooling and transferring system – It is the system used for recooling of casting after demoulding. It uses continuous conveyor, such as vibrating conveyor or overhead chain conveyor, and can be equipped with ventilating and spray cooling system.
Casting defect – It is an imperfection in a casting which does not satisfy one or more of the needed design or quality specifications. This term is frequently used in a limited sense for those flaws formed by improper casting solidification.
Casting design – It focuses on engineering a part and its mould so the liquid material flows smoothly, cools evenly, and solidifies without structural flaws.
Casting drawing – It is a technical blue-print used in manufacturing. It details the specific shape, dimensions, and extra material allowances needed to produce an unmachined cast part before it undergoes final precision cutting or finishing.
Casting fin – It is also called a flash. It is an unwanted protrusion of excess metal on a cast component.
Casting fracture – It refers to the structural failure or physical separation of a cast metal component caused by cracks which propagate through the material. These fractures can occur either during the solidification and cooling phase inside the mould (as a processing defect) or later when the finished part is subjected to mechanical stress during service.
Casting layout – It is the overall spatial arrangement and configuration of a metal casting system inside a mould. It maps out the product cavity, gating network (sprues, runners, and gates), risers, and cooling channels to ensure proper metal flow and sound solidification. Alternatively, in mechanical inspection, it means checking a cast part’s dimensions against technical blue-prints.
Casting machine – It is an industrial tool which pours or forces liquid metal into a mould. The metal cools and hardens inside the mould to form a specific shape.
Casting methods -These are manufacturing processes where liquid material, normally molten metal, is poured into a hollow mould and allowed to cool and solidify into a specific shape. Common types of casting methods are sand casting, die casting, investment casting, centrifugal casting, and continuous casting.
Casting modulus – It is a simplified approach to determining solidification time. The time is proportional to the square of the section modulus (the ratio of volume to surface area). It is also known as Chvorinov’s rule.
Casting mould – It is a specialized forming tool or container featuring a hollow cavity which receives molten metal, shaping it as the liquid cools and solidifies.
Casting, open sand – Open sand casting is a basic metal casting method where molten metal is poured directly into an unsealed, single-part sand mould (the drag) that has no top covering, cope, or upper half. The top surface of the metal remains exposed to the air and settles flat under gravity.
Casting plant – It is an industrial manufacturing facility where liquid materials, very frequently molten metals like iron, steel, or aluminum, are poured into shaped moulds and allowed to solidify to create specific manufactured components.
Casting plant layout – It is the physical arrangement of machines, melting furnaces, moulding stations, storage, and material handling systems inside a metal-casting facility. Its main goal is to ensure a smooth, safe, and fast flow of materials from raw metal to finished castings at a low cost.
Casting porosity – Porosity in casting is a defect where tiny air pockets, gas bubbles, or empty voids form inside or on the surface of a metal part as it cools and hardens. These holes weaken the metal, cause leaks in pressure parts, and ruin surface finishes.
Casting process – It is a manufacturing process where liquid material, normally metal, is poured into a mould with a hollow shape. The liquid cools and hardens into a solid object called a casting. It helps make complex shapes which are hard or costly to build with other methods.
Castings, failure analysis – Metallurgical failure analysis of castings is the systematic engineering process of investigating a cast metal component that has broken or failed to perform its function, in order to identify the root cause.
Casting section thickness – It is the wall thickness of the casting. Since the casting cannot have a uniform thickness, the section thickness can be specified at a specific place on the casting. Also, it is sometimes useful to use the average, minimum, or typical wall thickness to describe a casting.
Casting shrinkage – It is the quantity of dimensional change per unit length of the casting as it solidifies in the mould or die and cools to room temperature after removal from the mould or die. There are three distinct types of casting shrinkage. Liquid shrinkage refers to the reduction in volume of liquid metal as it cools to the liquidus temperature. Solidification shrinkage is the reduction in volume of metal from the beginning to the end of solidification. Solid shrinkage involves the reduction in volume of metal from the solidus temperature to room temperature.
Castings inspection – It is the process of checking a metal component formed by pouring molten metal into a mould to ensure it meets specified quality, structural, and dimensional standards.
Casting speed – It is the rate at which molten metal is withdrawn or poured into a mould during manufacturing processes like continuous casting.
Casting strains – These are the strains in a casting caused by casting stresses which develop as the casting cools.
Casting stresses – These are stresses set up in a casting because of geometry and casting shrinkage. These are the residual stresses set up when the shape of a casting impedes contraction of the solidified casting during cooling.
Casting technology – It is a process in which molten metal is poured, injected or suctioned into the mould cavity and solidified to get metal parts or rough parts with certain shapes, sizes and properties.
Casting tolerance – It is the total allowable deviation between a casting feature’s nominal design size (the blue-print ideal) and its actual as-cast physical dimension. Since liquid metal undergoes volatile thermal and chemical transformations during solidification, exact physical dimensions cannot be perfectly replicated. Tolerances define the acceptable window for parts to function correctly without unnecessary machining.
Casting transitions – Casting transitions occur at the start of casting, during ladle exchanges and submerged entry nozzle (SEN) changes, and at the end of the casting sequence. Inclusions are frequently generated during transitions and can continue for a long time, hence contaminate a large quantity of steel. During these unsteady casting periods, slag entrainment and air absorption are more likely, which induce reoxidation problems.
Casting volume – It is the total cubic units (cubic millimeters) of cast metal in the casting.
Casting yield – It is the weight of a casting(s) divided by the total weight of metal poured into the mould, expressed as a percentage.
Cast-in-place – It is also called pour-in-place or in-situ concrete. It is a construction method where liquid concrete is poured, compacted, and cured directly at the job site inside temporary moulds called formwork.
Cast-in plate – It is a steel plate with welded anchors or studs set flush into concrete. It gives workers a solid metal spot to bolt or weld steel beams and framing.
Cast iron – It is a generic term for a large family of cast ferrous alloys with a carbon content higher than the maximum solubility in austenite at the eutectic temperature. Most commercial cast irons contain between 1.8 % carbon and 4.5 % carbon. This means that carbon is present in excess of the quantity which can be retained in solid solution in austenite at the eutectic temperature. In addition to carbon, there are also present, varying quantities of silicon (1 % to 3 %), manganese, sulphur and phosphorus. These irons can normally be divided into the several types. Grey (also spelled as gray) cast iron, in which all or part of the carbon content is in the form of graphite distributed through the metal as flakes which are responsible for the inherently poor shock-resistance and relatively low mechanical properties of the material. White cast iron, in which practically the whole of the carbon is retained in chemical combination with the iron as carbide of iron. This compound has a silver-white colour and the fractures of the cast iron are white. White iron is very hard and brittle and practically unmachinable, and is used mainly as an intermediate product in the production of malleable iron castings or a thin hard layer on the surface of a softer iron casting. Malleable cast iron is cast white and then annealed at around 850 deg C. to remove carbon (white-heart process) or to convert the cementite to rosettes of graphite (black-heart process). It is distinguished from grey and white cast iron by showing some elongation and reduction of area in a tensile test. Spheroidal graphite cast iron, in which, as the name implies, the graphite is in spheroidal form instead of flakes, as found in grey cast iron. The production of this iron involves the addition of an appropriate quantity of either magnesium or cerium to the molten iron shortly before casting. The mechanical strength is doubled and such castings show measurable ductility and highly increased shock resistance. Alloy cast iron contains a specially added element or elements in amounts sufficient to produce a measurable modification of the physical properties.
Cast iron casting – It is a metalworking process where molten cast iron is poured into a mould to solidify and form a desired shape. It is a normal method for creating several industrial and infrastructure products because of the to cast iron’s properties like high strength, wear resistance, and excellent castability.
Cast iron castings – These are metal parts produced by pouring molten cast iron into a mould, where it solidifies and takes the shape of the mould cavity. This process, also known as cast iron casting, leverages the properties of cast iron, a ferrous alloy with a high carbon content (typically 2.1 % to 4.5 %), to create durable and versatile components.
Cast iron pipe – It is a heavy, rigid cylindrical tube made predominantly from gray cast iron. Cast iron pipes are strong but brittle pipes mainly used for drain, waste, vent, and underground water or sewage distribution systems applications because of their low ductility and malleability. They are manufactured using methods such as the pit, horizontal, or centrifugal method, allowing for complex shapes and machining.
Cast iron rolls – These are heavy cylindrical tools made of iron-carbon alloys with 2.5 % to 3.5 % carbon, used in rolling mills to shape hot or cold metal into sheets, plates, and bars. Main types of cast iron rolls are chilled cast iron rolls, infinite chilled cast iron rolls, ductile iron rolls, and high chromium cast iron rolls.
Cast iron stave cooler – It is a cooling device used in the blast furnace. It is made of cast iron, typically with internal water channels, installed on the inner surface of the furnace shell. It protects the shell from the high temperatures generated during iron production and helps maintain the furnace’s profile.
Cast iron surface plate – It is a heavy, rigid block of precision-machined metal used as a true horizontal reference plane. Machinists use it as a flat base-line to measure parts, lay out cuts, and set up tools.
Cast iron valve – It is a mechanical device with a body and bonnet made of cast iron, used to start, stop, or regulate the flow of liquids and gases inside a pipe-line.
Cast joint – It is a specialized connection component, normally made of cast steel or cast iron, formed by pouring molten metal into a mould. These joints connect structural members, such as tubular braces in offshore platforms, bridges, or complex frame systems.
Cast layer – It typically refers to a thin film formed by applying a viscous polymer solution to a support and drying it, or a specialized surface coating / working layer formed directly during a casting process to improve properties like wear or corrosion resistance.
Castle nut – It is also called castellated nut. It is a specialized hex nut with a distinct, slotted cylindrical crown on top which resembles a medieval castle turret, designed to lock onto a pre-drilled bolt using a cotter pin.
Cast magnesium – It refers to light-weight magnesium alloys which are melted and poured or injected into moulds to form complex, near-net-shape components.
Cast materials – These are metals and metal alloys melted into a liquid state and poured into a mould cavity to solidify into a specific, often complex shape.
Cast metal – It refers to any metal object or material produced by pouring molten liquid metal into a hollow mould, where it cools and hardens into a specific shape. The final solid object is also called a casting.
Cast nickel alloys – These are high-performance metal mixtures with nickel as the main element, shaped by pouring molten liquid into moulds to form complex parts.
Cast nickel-base proprietary alloys – These are specialized, custom-formulated metals designed for high-performance applications where standard industry-grade alloys fail. These alloys contain nickel as the main base element and are shaped using casting processes (pouring molten metal into moulds) to create complex, near-net-shape components. The term ‘proprietary’ means the chemical composition, heat-treatment processes, and manufacturing methods are patented or trade-marked by specific metal manufacturers.
Cast nickel-base superalloys – These are high-performance metal mixtures shaped by pouring liquid metal into a mold, built to handle extreme heat, high pressure, and chemical wear without breaking. Nickel forms the main body since it keeps a stable face-centered cubic (fcc) crystal shape even when very hot.
Cast nickel-chromium alloys – These are high-performance metal mixtures shaped by pouring molten nickel and chromium, frequently combined with iron, molybdenum, or niobium, into a mould to create durable components which resist extreme heat and corrosion. These are mainly composed of nickel (nickel-base) with 15 % to 40 % chromium. The alloys frequently include molybdenum, iron, aluminum, or silicon to improve strength and stability.
Cast nickel-chromium iron alloys – These are high-performance metal mixtures shaped by pouring molten liquid into moulds, combining nickel, chromium, and iron to resist extreme heat and corrosion. These alloys typically contain 14 % to 60 % nickel, 18 % to 33 % chromium, and 15 % to 57 % iron.
Cast nickel-chromium-iron-cobalt-copper-silicon alloys – These are a specialized class of high-performance, multi-element super-alloys designed for extreme environments needing exceptional resistance to wear, galling, corrosion, and high temperatures. These alloys are frequently classified under highly alloyed austenitic materials or complex cobalt-nickel base alloys (sometimes related to specific proprietary or wear-resistant families lor specialized high-entropy alloys).
Cast nickel-chromium-iron-molybdenum-cobalt-copper-silicon alloys – These are high-performance super-alloys designed to be shaped by casting, providing exceptional resistance to extreme corrosion, high-temperature oxidation, and mechanical stress. These alloys are complex, multi-element solid-solution strengthened superalloys where nickel (Ni) serves as the main base matrix. They integrate a precise balance of secondary metallic elements to perform reliably in hostile industrial environments.
Cast nickel-chromium-molybdenum alloys – These are high-performance, nickel-based austenitic super-alloys shaped through casting which combine exceptional corrosion resistance, high-temperature strength, and structural stability. The alloys contain nickel 40 % to 48 %, chromium 20 % to 38 %. And molybdenum 4 % to 21 %.
Cast nickel-chromium-molybdenum-copper iron alloys – These are high-performance materials designed to resist extreme corrosion and harsh chemical environments. In these alloys, nickel forms the main austenitic matrix, providing structural stability and toughness., chromium adds resistance to oxidizing acids, scaling, and high-temperature oxidation, molybdenum improves resistance to pitting, crevice corrosion, and reducing acids, copper improves resistance to sulphuric acid and specific reducing chemical environments, and iron and carbon acts as a balancing component and matrix modifier, frequently tied to cast-iron or complex alloy frameworks.
Cast nickel-copper alloys – These are metal mixtures formed by pouring molten copper and nickel (frequently with minor additions like iron, silicon, or manganese) into moulds to create solid components with high strength and exceptional corrosion resistance. These alloys typically feature copper as the base metal with 5 % to 30 % nickel (or higher in nickel-rich grades), combined with small quantities of iron, silicon, or tin.
Cast nickel-iron-chromium alloys – These are metal mixtures shaped in moulds which use nickel, iron, and chromium to survive extreme heat and harsh chemicals. These alloys mix three main elements in specific quantities, namely nickel 30 % to 46 %, chromium 12 % to 30 %, and iron remaining balance) which serves as the main base metal frame.
Cast nickel-molybdenum alloys – These are high-performance metal mixtures formed by pouring molten material into moulds, engineered with a nickel matrix and roughly 15 % to 30 % molybdenum to resist severe chemical corrosion and high heat. Nickel forms a stable austenitic matrix that provides high ductility and toughness. Molybdenum content is typically 15 % to 30 %, which delivers superior resistance to reducing acids (like hydrochloric and sulphuric acids). Additional elements can include minor quantities of iron, chromium, or cobalt to balance performance against localized pitting and mechanical stress. The alloy maintains structural stability and creep resistance well above 600 deg C.
Cast nickel-molybdenum-chromium alloys – These alloys are high-performance austenitic materials shaped by casting, combining nickel, 13 % to 38 % chromium, and 4 % to 21 % molybdenum to resist severe corrosion and high heat. Nickel base forms a stable austenitic matrix providing high ductility and structural strength. Chromium addition creates a passive oxide layer which defends against oxidizing environments and hot gases. Molybdenum content improves resistance to localized pitting, crevice corrosion, and reducing acids. This alloy allows creation of complex, near-net-shape components like pump bodies and valves used in severe industrial settings.
Cast nickel-silicon-copper alloys – These alloys are precipitation-hardening copper-based metal mixtures containing 1 % to 6 % nickel and 0.3 % to 2 % silicon. These alloys are shaped by pouring molten metal into moulds. Copper forms the main conductive and ductile matrix. Nickel (increases strength and high-temperature load performance, while silicon prevents oxidation. Controlled aging forms fine nickel silicide precipitates (Ni2Si) which harden the material without hurting electrical flow.
Castor oil – It is a bio-based, high-viscosity vegetable oil derived from ‘Ricinus communis’ seeds which serves as an effective polar lubricant, mould release agent, and chemical intermediate for metal processing fluids.
Castors – These are specially designed wheels affixed to the base of larger objects to facilitate their movement.
Cast part – It is a manufactured object created by pouring a liquid or molten material into a hollow mould and allowing it to solidify.
Cast pipe – It is a rigid tubular conduit formed by pouring molten metal, predominantly gray cast iron or steel, into a mould and allowing it to solidify in the shape of that mould.
Cast plate – It is a flat piece of metal, glass, or other material made by pouring a liquid form into a mould or onto a surface. The term applies to several different industrial and construction uses.
Cast replica – In metallography, it is a reproduction of a surface in plastic made by the evaporation of the solvent from a solution of the plastic or by polymerization of a monomer on the surface.
Castrip – It is the process to directly cast molten steel into a final shape and thickness without additional hot or cold rolling. This reduces capital investment, energy, and environmental cost.
Cast stainless steel – It is an iron-based, chromium-bearing alloy shaped into complex components by pouring molten metal into a u rather than forging or machining it from wrought stock.
Cast steel – It is a ferrous alloy of iron and carbon with up to 2 % carbon content which is shaped by pouring molten metal into a mould. It is steel in the form of a casting.
Cast steel rolls – These are heavy cylindrical tools made by pouring molten steel into a mould, used in rolling mills to shape and process hot or cold metal. Carbon content typically ranges from 0.4 % to 1.4 % for standard steel rolls, and up to 2.4 % for semi-steel grades. Alloys like chromium, nickel, and molybdenum are frequently added to boost hardness and wear resistance. These rolls offer high tensile strength, toughness, and thermal shock resistance compared to brittle cast iron alternatives. Micro-structure is normally composed of ferrite and pearlite matrices, with higher carbon variants developing dispersed alloy carbides.
Cast strip – It refers to a continuous, thin semi-finished sheet of metal produced directly from molten metal using the strip casting process. Rather than casting heavy ingots or thick slabs which are required to undergo energy-intensive reheating and multiple rough hot-rolling stages, strip casting integrates casting and hot rolling into a single, seamless step. The resulting metal sheet typically ranges from 1 millimeter to 5 millimeters in thickness, closely mimicking its final net-shape dimensions.
Cast structure – It is the metallographic structure of a casting evidenced by shape and orientation of grains and by segregation of impurities.
Cast sump – It is a shaped casting. It is a structural, bowl-shaped metal component designed to collect, store, and cool fluids at the bottom of a mechanical system.
Cast tooling plate – It is a precision-machined, thermally stress-relieved metal plate, very frequently aluminum, designed for high dimensional stability and flatness. It is manufactured by casting the metal, machining both flat surfaces to a fine finish, and removing internal stresses so it does not warp or distorts when cut or heated. It is used for machine bases, jigs, and fixtures.
Cast-weld assembly – It is a hybrid component made by joining separate cast metal pieces, or by welding a casting to wrought metal plates, shapes, or forgings. This method is used to build large or complex structures which are too hard or costly to pour as a single piece.
Cast-weld construction – It is a hybrid manufacturing method which combines metal casting and welding. Complex, high-integrity components are created by joining pre-cast metal pieces or fusing castings to rolled structural plates using industrial welding processes.
Cast-weld process – It is a manufacturing method where large, complex, or hard-to-cast metal components are broken down into two or more smaller, simpler cast shapes, which are then permanently joined together using welding.
Catadioptric camera – It is an imaging system which combines lenses (refractive elements) and curved mirrors (reflective elements) to capture a wide or omnidirectional field of view. The word combines catoptrics (the study of reflection) and dioptrics (the study of refraction). These cameras are widely valued since they can achieve a 360-degree or hemispherical view while maintaining a single effective centre of projection (single viewpoint).
Catadioptric system – It is an optical setup which combines both reflection (using curved mirrors, or catoptrics) and refraction (using lenses, or dioptrics) to form images or manipulate light.
Catagenesis – It is the subsurface geological process where buried organic matter (kerogen) undergoes thermal cracking under high temperatures and pressures to generate liquid and gaseous hydro-carbons. It represents the critical middle stage of hydro-carbon generation, frequently referred to as the ‘oil and gas window’.
Catalog – It is a document which provides information on services and /or product offered by a vendor or service provider. The main elements in a catalog include product or service name, descriptions, hierarchy, prices and internal codes. On-line forms of catalogs are called e-catalogs and these normally support online order placements and payments.
Catalysis – It is the process of adding a catalyst to facilitate a reaction.
Catalyst – It is a substance capable of changing the rate of a reaction without itself undergoing any net change. It differs from a curing agent in that the catalyst is not itself chemically consumed in the reaction, while a curing agent is. Technically, catalysts which increase reaction rates are called accelerators, and those which decrease reaction rates are called inhibitors or retarders.
Catalyst bed – It is a stationary or moving mass of solid catalyst particles, formed as pellets, granules, or extrudates, contained within a reactor vessel through which reactant gases or liquids flow to promote a chemical reaction.
Catalyst bed exit gas – It is the process gas or vapour mixture which leaves a catalyst bed after completing a chemical reaction. It contains reacted products, unreacted feed components, and inert carriers.
Catalyst bed feed gas – It is the mixture of reactant gases introduced into a catalytic reactor bed to initiate and sustain specific chemical reactions. It contains specific reactants and diluents or carrier gases depending on the industrial process. In multi-stage reactors, it can also include intermediate reaction products from prior beds. Catalyst bed feed gas drives the chemical conversion, determines the reaction rate, and manages the thermal or heat balance within the catalyst bed.
Catalyst bed input – It refers to the raw feed streams, thermal states, and physical properties introduced into a packed or fixed bed reactor to initiate catalytic reactions.
Catalyst deactivation – It refers to the loss of catalytic activity because of the factors such as active site poisoning by contaminants, clogging of pores by coke, mechanical attrition, or chemical variations which diminish the active species on the catalyst’s surface. This phenomenon is indicated by a decreased rate of reaction and a reduction in the quantity and quality of products.
Catalyst layer – It is the thin, porous active region inside electro-chemical devices like fuel cells and electrolyzers where electro-chemical reactions take place. It is a nano-structured composite electrode, typically 5 micrometers to 30 micrometers thick, which drives conversion efficiency by hosting half-cell reactions. It is made of precious metal catalysts (like platinum nano-particles) supported on conductive carbon particles and bound together by a proton-conducting polymer (ionomer).
Catalyst particle – It is a discrete solid unit, frequently shaped as a pellet, sphere, or extrudate, composed of an active catalytic phase dispersed on a high-surface-area carrier which accelerates chemical reaction rates without being consumed.
Catalyst pellet – It is a shaped, millimeter-sized solid particle containing active catalytic material used in industrial fixed-bed reactors to speed up chemical reactions. These pellets contain tiny internal pores that provide a massive surface area for reactants to touch. They are engineered to withstand high pressures and physical wear inside large reactors without crushing into powder.
Catalyst poisoning – It is the partial or total loss of a catalyst’s activity because of the strong chemical interactions between impurities and the catalyst’s active sites. Unlike physical fouling or thermal aging, poisoning involves specific chemical bonds that block reactants from reaching the active surface.
Catalyst surface – It is the active boundary area of a solid catalyst where reactant molecules attach, interact, and transform during a chemical or electro-chemical reaction.
Catalyst surface temperature – It refers to the actual thermal state of the active solid boundary where a heterogeneous catalytic reaction occurs, which frequently differs considerably from the surrounding bulk gas temperature due to localized exothermic or endothermic reaction heats.
Catalyst utilization – It measures the fraction of active catalytic sites which successfully participate in a chemical or electro-chemical reaction compared to the total available sites.
Catalytic combustor – It is a system which promotes chemical reactions between fuel and air, enabling combustion at lower temperatures and equivalence ratios, hence reducing pollutants such as nitrogen oxides (NOx) considerably compared to conventional combustion systems. It is designed to convert carbon mono-oxide (CO) and unburned hydro-carbons into carbon di-oxide and water, frequently needing a separate combustion chamber during start-up and idle conditions.
Catalytic conversion of methane – It is a process which uses a specialized material called a catalyst to transform methane gas into valuable chemicals, fuels, or clean energy components at controlled temperatures and pressures. A catalyst is a substance which speeds up a chemical reaction or allows it to happen with less heat, without being used up in the process. Since methane (CH4) has very tight, stable molecular bonds, this conversion needs advanced catalysts to make the reaction efficient.
Catalytic converter – It is an air pollution abatement device which removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon di-oxide and water or reducing them to nitrogen.
Catalytic cracking – It is a process which breaks down complex hydro-carbons into simpler, lighter molecules using catalysts, improving the yield and quality of products such as gasoline and kerosene while reducing residuals. It operates at lower temperatures and pressures compared to thermal cracking, facilitating the conversion of heavy feedstock into desirable lighter fractions.
Catalytic debinding – It is an advanced manufacturing process used in powder metallurgy, metal injection moulding (MIM), ceramic injection moulding (CIM), and sinter-based 3D printing. It is the chemical removal of a main polymer binder from a moulded ‘green’ part using a gaseous catalyst, preparing the component for high-temperature sintering. The process transitions a fragile, polymer-heavy ‘green part’ into a porous, geometrically stable ‘brown part’ without risking the structural distortion common in traditional thermal methods.
Catalytic filter candle – It is a cylindrical, porous ceramic or metal filtration element engineered to simultaneously capture particulate matter and chemically convert gaseous pollutants or by-products in high-temperature gas streams.
Catalytic filter elements – These are filtration devices which combine dust filtration with catalytic oxidation or reduction of gaseous pollutants, hence integrating multiple unit operations to improve efficiency and reduce costs and footprint.
Catalytic gasification – It is a thermo-chemical process which uses a catalyst to convert carbon-rich materials into a clean, energy-dense gas mixture at lower operating temperatures than traditional methods.
Catalytic hydrogenation reaction – It is a chemical process which involves the addition of hydrogen to organic compounds, typically facilitated by catalysts, either in heterogeneous or homogeneous forms, to achieve selective transformations. This process is recognized for its atom economic efficiency and is widely applied in the production of specialty and fine chemicals.
Catalytic incineration – It is a process which uses a catalyst to oxidize organic contaminants into carbon di oxide (CO2) and water at lower temperatures than traditional thermal incineration.
Catalytic liquefaction – It is a thermo-chemical conversion process which uses a catalyst and high temperature or pressure to transform solid carbon-based materials, such as coal or biomass, into liquid synthetic fuels or bio-crude oil.
Catalytic membrane reactor – It is an advanced device which combines a chemical reaction, a catalytic process, and selective membrane separation into a single integrated unit.
Catalytic oxidation – It is a process which uses a catalyst to accelerate the breakdown of harmful gases, such as volatile organic compounds (VOCs) and carbon mono-oxide (CO), into harmless by-products like carbon di-oxide and water vapour at lower operating temperatures.
Catalytic plate reactor -It is an advanced chemical reactor which uses a series of flat metal plates with narrow channels coated with a catalyst to drive chemical reactions with high heat and mass transfer efficiency.
Catalytic process – It is a chemical process where the speed of a reaction is increased by an added substance called a catalyst, which is not consumed or permanently altered in the reaction.
Catalytic property – It is a material’s ability to increase the rate of a chemical reaction by lowering its activation energy without being consumed or permanently changed by the process.
Catalytic pyrolysis – It is an advanced thermochemical process that breaks down organic materials, such as biomass or waste plastics, at high temperatures in the absence of oxygen using a catalyst to steer chemical reactions and upgrade product quality.
Catalytic reaction – It is a chemical reaction that is facilitated by a catalyst, which alters the reaction rate without being consumed in the process. This reaction typically shows a lower rate-limiting free energy of activation compared to an uncatalyzed reaction, resulting in an increased reaction rate.
Catalytic reformer – It is a unit which uses heat, pressure, and metal catalysts to turn low-octane petroleum naphtha into high-octane aromatic hydro-carbons and valuable hydrogen gas.
Catalytic reforming – It is a chemical process which converts naphthenes and other saturated hydro-carbons in heavy naphtha into C6-C10 aromatics and hydrogen, utilizing catalysts such as platinum and platinum / rhenium supported on gamma alumina. This process improves the octane number of gasoline and produces feedstock for petrochemical production.
Catalytic reforming process – It is an industrial process which converts low-octane naphtha from crude oil into high-octane liquid products called reformates and valuable aromatic petrochemicals.
Catalytic steam reforming – It is an industrial chemical process which reacts hydro-carbons, such as methane from natural gas, with steam over a catalyst at high temperatures to produce synthesis gas (a mix of hydrogen and carbon mono-oxide). Methane and steam (CH4 + H2O) are heated under pressure (0.3 mega-pascals to 2.5 mega-pascals) in the presence of a metal catalyst (normally nickel) to form carbon mono-oxide and hydrogen (CO + 3H2). This reaction is endothermic, meaning it needs added heat. The resulting carbon mono-oxide reacts with more steam (CO + H2O) to produce extra hydrogen and carbon di-oxide (CO2 + H2).
Catalytic system – It is an emissions-control device which uses active chemical substances to turn toxic exhaust gases into safer, less harmful by-products.
Catalyzed hydrolysis – It is a chemical reaction where water breaks down a compound’s chemical bonds much faster since a catalyst helps speed up the process.
Cataracting motion – The cataracting motion in a rotary kiln is typical with the beginning of a particles throwing away from the bed in the freeboard of the cylinder. With the increase of the rotation speed, the quantity of the ejected particles and the length of their trajectory grow, while a fully covering of the cylinder wall with the treated material is turned out.
Catastrophic carburization – It is also known as metal dusting. It is a severe form of high-temperature corrosion which occurs when carbon penetrates iron-based, nickel-based, or cobalt-based alloys, causing them to disintegrate into a powdery mixture of metal particles, graphite, and carbides. This phenomenon typically occurs in carbon-rich environments (such as synthesis gas, hydro-carbons, or carbon mono-oxide atmospheres) at high temperatures, normally ranging between 400 deg C and 800 deg C.
Catastrophic consequence – It is a sudden, disastrous, and far-reaching result of an action, event, or failure that causes massive destruction, severe harm, or widespread loss.
Catastrophic damage – It refers to severe material degradation which occurs when laser irradiance exceeds a specific threshold, resulting in effects such as pitting, cracking, and vapourization, frequently accompanied by a flash of light and a sharp sound. This type of damage considerably impairs the optical performance of materials previously transparent to the laser light.
Catastrophic die failure – It is a sudden, total, and irrecoverable fracture where large pieces of a metal-forming die break away or shatter during operation.
Catastrophic event – It is a climate related event having sudden onset and widely distributed and large magnitude impacts on human or natural systems such as historically rapid sea level rise or sudden shifts (over a decade or less) in atmospheric or oceanic circulation patterns. Such events have occurred in the past because of the natural causes.
Catastrophic failure – It is sudden failure of a component or assembly which frequently results in extensive secondary damage to adjacent components or assemblies.
Catastrophic failure condition – It is a system breakdown which results in multiple fatalities and normally the total loss of the equipment, facility, or system.
Catastrophic fracture – It is a sudden, highly rapid, and total structural failure of a material or component caused by the uncontrolled propagation of a crack.
Catastrophic wear – It is the sudden surface damage, deterioration, or change of shape caused by wear to such an extent that the life of the part is appreciably shortened or action is impaired.
Catchment area – It is an area which collects and drains precipitation.
Category – Category is the primary basis for classification using each of the three fundamental criteria of environmental-socio-economic viability (related categories being E1, E2, and E3), technical feasibility (related categories being F1, F2, F3 and F4), and degree of confidence (related categories being G1, G2, G3 and G4) as per UNFC (United Nations Framework Classification for Resources) classification.
Categorical variable – It is a variable with values which range over categories, rather than being numerical. Examples include gender (male, female), paint colour (red, white, blue), type of animal (elephant, leopard, lion). Some categorical variables are ordinal.
Categorization – It is the process of sorting data, objects, or system components into specific groups based on shared traits or functions.
Catenary – It is the curve which an idealized hanging chain or cable assumes under its own weight when supported only at its ends in a uniform gravitational field. The catenary curve has a U-like shape, superficially similar in appearance to a parabola. It is also a measure of the difference in length of the strands in a specified length of roving as a result of unequal tension. It is also the tendency of some strands in a taut, horizontal roving to sag more than the others.
Catenary idlers – These are a type of flexible belt-carrying idlers with ends supported in pivoted stands.
Catenary load – It is the dynamic force imposed on a conveyor belt by the weight of the conveyed material, influencing tension and demanding meticulous monitoring.
Catenary sag – It is the inherent sag or curvature of the conveyor belt between two points, needing periodic adjustments to ensure optimal tension.
Catchment characteristics – These are the physical, geographical, and environmental features of a drainage basin that control how it collects, stores, and releases water.
Cathode – It is the negative electrode of an electrolytic cell at which reduction is the principal reaction. Electrons flow toward the cathode in the external circuit. Typical cathodic processes are cations taking up electrons and being discharged, oxygen being reduced, and the reduction of an element or group of elements from a higher valence state to a lower valence state. In electro-galvanizing process positive current flows from the anode (zinc) through the electrolyte to the cathode (steel).
Cathode bias – It is a circuit design technique used in vacuum tube electronics to set the proper operating point by placing a resistor between the tube’s cathode and ground.
Cathode body – It refers to the bulk, solid physical structure of a cathode electrode. Its exact definition and function depend heavily on the field where it is used.
Cathode chamber – It is the specific section of an electro-chemical system where reduction reactions take place using electrons from an external circuit.
Cathode circuit – It is the specific wiring configuration and pathway which connects the cathode (the electrode where electrons enter a device or conventional current departs) to other components in an electrical or electronic system.
Cathode copper – It is the copper deposited at the cathode in electrolytic refining.
Cathode efficiency – It is frequently called cathode current efficiency or faradic efficiency at the cathode. It is the ratio of the actual quantity of metal deposited or product generated at the cathode to the theoretical amount predicted by Faraday’s laws of electrolysis. Engineers use cathode efficiency to measure how well electrical current drives the desired reduction reaction (like metal plating or ion reduction) instead of wasting energy on side reactions. Cathode efficiency in % = [(Actual mass deposited) / (theoretical mass calculated)] x 100.
Cathode electrolyte interphase – It is a thin protective film which naturally forms on the surface of a battery’s positive electrode when the electrolyte breaks down during use.
Cathode film – It is the portion of solution in immediate contact with the cathode during electrolysis.
Cathode follower – It is a vacuum tube amplifier circuit where the input signal is applied to the control grid and the output is taken from the cathode. It is also known as a common-anode amplifier or a valve buffer.
Cathode gauge – It is an ionization sensor used to measure low pressure, or vacuum levels, by ionizing gas molecules and reading the resulting electrical current.
Cathode junction – It is the specific connection point in a circuit where multiple cathodes meet, or a connection junction used in cathodic protection systems to measure and balance protective electrical currents.
Cathode matrix – It is the structural and material framework inside a battery or electro-chemical cell which holds the active cathode material together while maintaining electrical conductivity and ion transport.
Cathode ray oscilloscope – it is an electronic instrument which displays the wave shape of electrical signals on a cathode ray tube.
Cathode-ray tube – It is a specialized vacuum tube in which images are produced when an electron beam strikes a phosphorescent surface. It is an electronic tube which permits the visual display of electronic signals.
Cathode-ray tube (CRT) display – It is a specialized vacuum tube which converts electrical video signals into visible images by directing a focused beam of high-velocity electrons onto a phosphor-coated screen.
Cathode side – It is the electrode of an electrical device or electro-chemical cell where reduction (gain of electrons) takes place and conventional current departs.
Cathode spot – It is a tiny, highly active area on a cathode surface where intense electron emission, metal vapourization, and dense plasma generation occur in an electric or vacuum arc.
Cathode surface – It is the physical boundary or outer layer of a cathode electrode where reduction reactions, electron acceptance, or electron emission take place.
Cathode voltage – It is the electrical potential (measured in volts) at the cathode electrode relative to a reference point, such as ground or another electrode in the system.
Cathodic – It is the exhibiting properties of a cathode. Steel is cathodic in relation to zinc.
Cathodic arc – It is an electrical discharge in a vacuum which creates a high-current, low-voltage arc on a negatively charged cathode, vapourizing and ionizing its solid material.
Cathodic cleaning – It is the electrolytic cleaning in which the work is the cathode.
Cathodic corrosion – It is the corrosion resulting from a cathodic condition of a structure normally caused by the reaction of an amphoteric metal with the alkaline products of electrolysis.
Cathodic current density – It is the quantity of electric current flowing into a unit surface area of a cathode. It is the current per square meter needed to achieve cathodic protection of a bare metal surface, with specific values indicating initial, final, and mean design current densities needed for effective protection.
Cathodic delamination – It is the failure and separation of an organic coating from a metal surface caused by electro-chemical reactions at the coating-substrate interface.
Cathodic disbondment – It is the destruction of adhesion between a coating and its substrate by products of a cathodic reaction.
Cathodic etching – It is done for cleaning of the surfaces of metal samples prior to oxygen determinations. The sample becomes the cathode in a low-pressure argon-ion discharge. The argon ions bombard the surface of the sample and remove the oxide film by an etching process.
Cathodic inhibitor – It is a chemical substance or mixture which prevents or reduces the rate of the cathodic or reduction reaction.
Cathodic pickling – It is the electrolytic pickling in which the work is the cathode.
Cathodic polarization – It the deviation of an electrode’s potential in the negative direction away from its open-circuit or free-corroding potential (Ecorr) because of the passage of an electrical current. When a metal structure undergoes cathodic polarization, electrons accumulate at its surface, forcing it to act exclusively as a cathode. This process systematically drives reduction reactions while heavily suppressing anodic dissolution (oxidation), effectively controlling or preventing corrosion. It is the change of the electrode potential in the active (negative) direction because of the current flow.
Cathodic protection – It is the reduction of corrosion rate by shifting the corrosion potential of the electrode toward a less oxidizing potential by applying an external electromotive force. It is also partial or complete protection of a metal from corrosion by making it a cathode, using either a galvanic or an impressed current. Zinc is higher in the electro-chemical series than iron, and corrodes sacrificially to prevent the corrosion of adjacent exposed steel. Pre-galvanized products (sheet, tube and wire) rely on this feature of the galvanized coating to protect the cut edges of products processed from these sections.
Cathodic protection system – It is a corrosion-control technology which protects metallic structures by making them the cathodic side of an electro-chemical cell, typically by connecting them to a more easily corroded metal acting as the anode. It is normally used for steel structures in contact with soil or submerged in water.
Cathodic reaction – It is the electrode reaction equivalent to a transfer of negative charge from the electronic to the ionic conductor. A cathodic reaction is a reduction process. An example common in corrosion is M(aq)2+ + 2e– M(s).
Cathodoluminescence – It is a radiative transition wherein low-energy light photons are released during electron irradiation.
Catholyte – It is the electrolyte adjacent to the cathode of an electrolytic cell.
Cation – It is a positively charged ion which migrates through the electrolyte toward the cathode under the influence of a potential gradient.
Cation exchange capacity – It is a measure of how many positively charged ions (cations) a soil can hold on the surfaces of its particles.
Cation exchange chromatography – It is a separation technique which isolates positively charged molecules by using a negatively charged stationary phase. It is a form of ion exchange chromatography (IEX), which is used to separate molecules based on their net surface charge. It uses a negatively charged ion exchange resin with an affinity for molecules having net positive surface charges. Cation exchange chromatography is used both for preparative and analytical purposes.
Cation exchange layer – It is a selective, negatively charged barrier or film which allows positively charged ions (cations) to pass through while blocking negatively charged ions (anions).
Cation exchange membrane – It a specialized plastic film that lets positively charged ions pass through while blocking negatively charged ions. It is a selective barrier which allows the passage of cations, particularly protons, while separating the anode and cathode compartments in electrochemical systems.
Cation exchange resins (R.H+) – These resins are mainly styrene-divinyl benzene copolymers, which on sulphonation or carboxylation, become capable to exchange their hydrogen ions with the cations in their water. The cations exchange sulphonic acid-formaldehyde resin exchange their H+ ions with the cations present in the water i.e., Ca2+ and Mg2+.
Cationic asphalt emulsion – It is a thermodynamic metastable system where asphalt droplets are stabilized by cationic emulsifiers, which can interact with reactive cement grains, influencing the hydration process and overall stability of composite materials.
Cationic detergent – It is a detergent which produces aggregates of positively charged ions with colloidal properties.
Cationic photo-polymerization – It is a light-triggered chemical process where light-sensitive compounds absorb radiation to generate strong acids, which then turn liquid monomers into solid polymers.
Cationic polymerization – It is a type of polymerization where the active centre of the growing polymer chain is a cation, allowing monomers to behave as nucleophiles and bond to the chain end, typically initiated by strong Bronsted or Lewis acids. This method is characterized by the reactivity of the counterion and the ability of certain vinyl monomers to stabilize the ion.
Cationic product – It is a chemical compound or formulation which carries a net positive electrical charge on its active molecules.
Cationic reaction – It refers to a type of polymerization where the active centre is a cation, and the monomer acts as a nucleophile, typically involving vinyl monomers with electron-releasing substituents that facilitate rapid propagation. These reactions are characterized by complex initiation processes and are frequently conducted in polar solvents, resulting in fast propagation rates and potential isomerization of monomers.
Cationic ring-opening polymerization – It is a chain-growth polymerization where a positively charged (cationic) reactive centre opens a cyclic monomer’s ring structure to form a linear or branched polymer chain.
Cationic surfactant – It is a surface-active compound which carries a positive electrical charge on its hydrophilic (water-loving) head group when dissolved in water. Like all surfactants, these molecules have a dual structure i.e., a water-attracting (hydrophilic) positive head and a water-repelling (hydrophobic) oil-attracting tail. Since majority of natural surfaces carry a slight negative charge in water, the positive charge of a cationic surfactant allows it to bind tightly to these surfaces.
Cationic system – It is a chemical or material set-up built around positively charged particles (cations) which actively interact with or bond to negatively charged targets.
Cationite – It is an ion-exchange resin used to remove positive ions (cations) from liquids by trading them for other ions, such as hydrogen.
Cationization – It is the chemical process of giving a molecule, fibre, or surface a positive electrical charge by adding cations (positively charged ions).
Cation resin – It is an insoluble synthetic polymer bead featuring fixed negative charges and mobile positive ions that selectively exchange positively charged ions (cations) from a surrounding fluid.
Cation-selective membrane – It is a specialized polymeric barrier which allows positively charged ions (cations) to pass while blocking negatively charged ions (anions).
Catoptric elements – These are optical components which use reflection to focus, redirect, or manipulate light. The most common examples of catoptric elements are mirrors, including flat, spherical, parabolic, and aspheric surfaces. Systems which rely entirely on these reflective components are known as catoptric systems.
Catoptric systems – These are optical systems which use mirrors as the main elements to form images or redirect light, completely avoiding the use of lenses. These systems rely entirely on the law of reflection (where the angle of incidence equals the angle of reflection) rather than refraction.
Catoptrics – It is the branch of optics which deals exclusively with the reflection of light and the formation of images using mirrors or reflective surfaces. Unlike systems which use lenses to bend light, a pure catoptric system relies solely on plane, spherical, or paraboloidal mirrors to manipulate light paths.
Cattierite (CoS2) – It is a rare cobalt sulphide mineral belonging to the pyrite group. While it originated as a purely mineralogical term, its definition refers to its synthetic counterpart (CoS2). Synthetic cattierite is heavily researched as a transition metal di-chalcogenide (TMD) with valuable electronic and catalytic properties.
Cauchy distribution – It refers to a mathematical profiling technique used mainly in X-ray diffraction (XRD) line broadening analysis to define and separate the physical effects of crystallite size from micro-strain within a metal matrix. Since a standard Cauchy distribution (mathematically identical to a Lorentzian distribution) has a sharp central peak and exceptionally heavy, flat tails, it is the standard choice for modeling specific structural irregularities in a material’s crystalline lattice.
Cauchy equation – It is the functional equation f(x + y) = f(x) + f(y). It serves as a fundamental tool in different fields.
Cauchy-green strain tensor – It is a fundamental measure of finite deformation in continuum mechanics which quantifies local changes in material length while separating pure stretch from rigid-body rotation.
Cauchy-green tensor – It is a fundamental measure of finite material deformation in continuum mechanics which separates pure stretching from rigid-body rotation.
Cauchy integral theorem – It states that the line integral of an analytic function around a closed contour inside a simply-connected domain is always zero.
Cauchy momentum equation – It is a foundational vector partial differential equation in continuum mechanics which describes the non-relativistic conservation of momentum for any continuous material (fluids or solids).
Cauchy problem – It is a specific type of initial value problem for a differential equation where people look for an unknown function which satisfies both the governing equation and precise conditions given on a specific surface or starting point.
Cauchy-Riemann conditions – These are a set of two partial differential equations which a complex function is to satisfy to be differentiable and analytic at a point.
Cauchy-Schwarz inequality – It states that the absolute value of the inner product of two vectors is less than or equal to the product of their individual norms (lengths).
Cauchy’s residue theorem – It is a tool used to evaluate complex line integrals by relating them to the sum of residues at the poles enclosed within a closed contour.
Cauchy’s theorem – It states that the contour integral of an analytic function around any closed path in a simply connected region equals zero.
Cauchy stress – It is also called true stress. It is a physical measure which describes the internal forces acting within a deformed material per unit of actual surface area.
Cauchy stress tensor – It is a second-order tensor which completely defines the internal state of true stress (force per unit actual deformed area) at any point within a material.
Caul – In adhesive bonding, it is a sheet of material used singly or in pairs in the hot or cold pressing of assemblies being bonded. A caul is used to protect either the faces of the assembly or the press platens, or both, against marring and staining in order to prevent sticking, facilitate press loading, impart a desired surface texture or finish, and provide uniform pressure distribution. A caul can be made of any suitable material such as aluminum, stainless steel, hardboard, fiberboard, or plastic, the length and width dimensions normally being the same as those of the plates of the press where it is used.
Caul plates – These are smooth metal plates which are free of surface defects, are of the same size and shape as a composite lay-up. These are used immediately in contact with the lay-up during the curing process to transmit normal pressure and temperature, and to provide a smooth surface on the finished laminate.
Caulk weld -It is a nonstandard term for seal weld which is a weld designed mainly to provide a specific degree of tightness against leakage.
Causal analysis – It is a structured investigative process used to determine the fundamental root cause of a system failure, defect, or mishap rather than just treating surface symptoms.
Causal effect – It is the difference between the study endpoint’s value if a subject experiences the treatment condition vs. its value if the same subject is to experience the control condition instead. This is a counter-factual definition since it is impossible to observe.
Causal filter – It is a system in signal processing whose output depends only on current and past input values, not on future inputs.
Causality – It is the principle that a system’s present output depends exclusively on past and current inputs, meaning an effect cannot occur before its cause.
Causality condition – It needs that a system’s output depends only on present and past inputs, meaning an output cannot appear before its corresponding input.
Causal sequence – It is a time-ordered series of values or an impulse response which remains strictly zero for all negative time indices (n is less than 0).
Causal system – It is a system whose output depends only on the present and past inputs, meaning it cannot react to future inputs.
Causative factor – It is a thing which helps cause a specific event, or condition to happen. It is an element, force, or condition which contributes directly or indirectly to producing an effect or result.
Cause and effect analysis diagrams – These are casual diagrams which show the causes of a specific event. Common uses of these diagrams are (i) product design and quality defect prevention, and (ii) to identify potential factors causing an overall effect. Each cause or reason for imperfection is a source of variation.
Causeways – It is a raised road or track constructed across low, wet ground, wetlands, or a shallow body of water.
Caustic – It means burning or corrosive. It is also a hydroxide of a light metal, such as sodium hydroxide or potassium hydroxide.
Caustic concentration – It measures the exact strength or percentage of a strong alkaline solution, specifically sodium hydroxide (NaOH, or caustic soda), dissolved in water.
Caustic corrosion – It is the deterioration of materials, particularly metals, because of the presence of highly alkaline substances, frequently exacerbated by incorrect pH levels in boiler water, leading to the dissolution of protective layers and the potential for stress corrosion cracking.
Caustic cracking – It is a form of stress-corrosion cracking very frequently encountered in carbon steels or iron-chromium-nickel alloys which are exposed to concentrated hydroxide solutions at temperatures of 200 deg C to 250 deg C. It is also known as caustic embrittlement.
Caustic degreasing – All steel products are degreased in a hot caustic solution as the first stage of the pretreatment process for galvanizing. The acid pickling is not effective unless all organic contamination, grease, and oil are removed from the steel’s surface. In the hot dip galvanizing process, organic residues are removed by immersing steel in a tank of caustic solution.
Caustic dip – It is a strongly alkaline solution into which metal is immersed for etching, for neutralizing acid, or for removing organic materials such as greases or paints.
Caustic embrittlement – It is an obsolete historical term denoting a form of stress-corrosion cracking most frequently encountered in carbon steels or iron-chromium-nickel alloys which are exposed to concentrated hydroxide solutions at temperatures of 200 deg to 250 deg C. In boilers, it is the phenomenon during which the boiler material becomes brittle because of the accumulation of caustic substances. This type of boiler corrosion is caused by the use of highly alkaline water in the high-pressure boiler.
Caustic environment – It is a highly alkaline setting, typically containing strong bases like sodium hydroxide or potassium hydroxide, which can chemically degrade materials and trigger specialized structural failures.
Caustic environments and stress corrosion cracking (SCC) – These combine to form a major degradation mechanism where alkaline chemicals and tensile forces cause fine, branching cracks in metals.
Caustic quenching – It is the quenching with aqueous solutions of 5 % to 10 % sodium hydroxide (NaOH).
Caustic scrubbers – These are essential industrial equipment used to neutralize acidic gases in exhaust streams. They employ a caustic solution, typically sodium hydroxide (NaOH), as a scrubbing medium, converting harmful acidic gases into harmless salts. Several Industries, where acid gas emissions are prevalent, extensively use these scrubbers.
Caustics method – The method of caustics is an optical technique used to measure stress concentration and determine the stress intensity factors around crack tips or sharp notches.
Caustic soda – It is sodium hydroxide which is also known as lye. It is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH-. Sodium hydroxide is a highly corrosive base and alkali which can cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon di-oxide from the air. It forms a series of hydrates NaOH.nH2O. The mono-hydrate NaOH·H2O crystallizes from water solutions between 12.3 deg C and 61.8 deg C. The commercially available sodium hydroxide is frequently this mono-hydrate.
Caustic soda solution – It is a concentrated, highly alkaline liquid made by dissolving sodium hydroxide (NaOH), normally known as lye, in water.
Caustic soda corrosion – It is the localized or general deterioration of metals caused by high concentrations of alkaline substances like sodium hydroxide (NaOH), frequently happening under high heat transfer or evaporation conditions.
Caustic treatment – It is the addition or use of a highly alkaline sodium hydroxide (NaOH) solution to remove acidic contaminants from hydro-carbon streams, mitigate corrosion in industrial boilers, or adjust pH in water treatment.
Cauer filter – It is also known as an elliptic filter’ It is a type of filter which shows ripples in both the passband and the stopband, characterized by a sharp transition between these bands while allowing for higher variation in group delay compared to other filter types.
Cavern thermal energy storage – It is a large-scale underground system which stores thermal energy, normally as hot or chilled water, inside engineered or repurposed rock cavities and subsurface tunnels.
Cavitating condition – It is a state where local static pressure in a liquid drop below its vapour pressure, causing vapour-filled bubbles to form and then violently collapse.
Cavitating jet – It is a high-speed fluid stream injected through a specialized nozzle into a liquid medium, intentionally designed to form and collapse vapour bubbles within the shear layer or core of the flow.
Cavitating propeller – It is a propeller which experiences a reduction in pressure on its blades sufficient to form cavities filled with air or water vapour, resulting from the difference between ambient pressure and the pressure generated by the propeller’s movement through water.
Cavitation – It is the formation and collapse, within a liquid, of cavities or bubbles which contain vapour or gas or both. In general, cavitation originates from a decrease in the static pressure in the liquid. It is distinguished in this way from boiling, which originates from an increase in the liquid temperature. There are certain situations where it can be difficult to make a clear distinction between cavitation and boiling, and the more general definition which is given here is hence to be preferred. In order to erode a solid surface by cavitation, it is necessary for the cavitation bubbles to collapse on or close to that surface.
Cavitation corrosion – It is the combined damage caused by mechanical shock waves from collapsing vapour bubbles and electro-chemical metal corrosion in a moving liquid. It is a process involving conjoint corrosion and cavitation.
Cavitation damage – It is the degradation of a solid body resulting from its exposure to cavitation. This can include loss of material, surface deformation, or changes in properties or appearance.
Cavitation erosion – It is the progressive loss of original material from a solid surface because of continuing exposure to cavitation.
Cavitation inception – It is the initial, precise moment or threshold when vapour cavities or bubbles first begin to form in a liquid flowing through a low-pressure region. It occurs when the local static pressure of a liquid drops below its saturated vapor pressure, triggering a phase change from liquid to vapour.
Cavitation modelling – It uses mathematical formulas in computer simulations to predict when and how vapour bubbles form and collapse in a flowing liquid.
Cavitation number – It is a dimensionless parameter used in fluid dynamics to measure the likelihood of vapour bubbles forming in a flowing liquid. It is the ratio of the difference between the pressure and vapour pressure to the dynamic pressure. It influences the sensitivity of cavitation in cryogenic fluids and different geometrical parameters.
Cavitation tunnel – It is a closed channel designed for testing propellers and ship models, where water is recirculated by an impeller, allowing for high hydrostatic pressure to prevent cavitation during tests. It features a test section with observation ports and can be equipped with devices to control turbulence and reduce dissolved gases.
Cavity – It is an internal or surface void, pore, or hole that occurs inside a metal casting or weld during solidification. Cavities happen because of the gas getting trapped in the molten pool or a lack of liquid metal to feed the area as it shrinks (shrinkage cavity). These flaws weaken the structural integrity and mechanical strength of the metal component. Cavity is also the mould impression or die impression which gives a casting its external shape. In forged dies, cavities are pockets, recesses, or indentations of regular or irregular contour which are impressed into a portion of a closed-die forging and which, except for the opening, are confined or enclosed by other forged elements. Normally, cavities are forged parallel to the direction of the ram. The size of cavities is very frequently expressed in terms of their length, width, and depth.
Cavity axis – It is the central longitudinal line along which an optical cavity or laser resonator is aligned to guide light propagation and ensure optimal reflection between mirrors.
Cavity collapse – It is the sudden implosion of vapour or gas-filled bubbles inside a liquid, or the structural cave-in of an underground void or rock pore under high pressure.
Cavity flow – It is a fluid dynamics phenomenon where a free-stream or moving fluid interacts with an indented opening, recess, or enclosed space (cavity), creating complex recirculation, shear layers, and acoustic oscillations.
Cavity formation – It refers to the creation of internal or surface voids, pores, or hollow spaces in a metal object during processes like casting, welding, or high-temperature stress.
Cavity halves – These halves refer to the two main matching sections of a mould tool which close together to form a hollow space where raw material is shaped. The two halves are the cavity half, and the core half.
Cavity insert – It is a removable, interchangeable modular block inside an injection mould which shapes the exterior surface of a moulded part.
Cavity length – It is the axial distance of pure steam within a steam cavity, particularly in the context of sonic steam jet condensation. It can be measured through methods such as high-speed video analysis or temperature profiling along the nozzle axis.
Cavity loss – It is the total quantity of optical, microwave, or acoustic energy which escapes or gets absorbed inside a resonant chamber during each reflection or round trip.
Cavity method – It refers to a field technique or mathematical modelling approach for evaluating hollow spaces under physical stress. In radio-frequency (RF), microwave, and materials engineering, the cavity method is an experimental technique used to measure the electro-magnetic properties of a material. In computer science, machine learning, and network engineering, the cavity method is an analytical technique used to solve large-scale optimization and probability problems on graphs or networks.
Cavity, mould – Mould cavity is the hollow, female half of a mould which defines the external shape and outer surface of a moulded part. It shapes the outside of the product and controls its visual look and surface finish.
Cavity of a concave die – It is the hollow, recessed, or inwardly curved geometric space machined into a tool steel block (the die) which receives and shapes metal work-pieces. When raw or molten metal is forced into this concave recess via a punch, hydraulic fluid, or high-pressure injection, it takes on the inverse (convex) shape of that cavity.
Cavity pressure – It is the gas pressure within a cavity which can potentially cause hydraulic fracturing of the surrounding geological medium, influenced by the compressive hoop stress in the material outside the cavity.
Cavity radius – It is the distance from the centre to the inner wall of a hollow space, pore, or cylindrical / spherical void inside a material or structure.
Cavity receiver – It is an enclosed, insulated heat-absorbing receptacle which captures concentrated radiant energy, very frequently solar radiation, through a small opening called an aperture.
Cavity surface – It refers to the hollow, recessed female side of a mould or die which defines the external shape, dimensions, and surface finish of a manufactured part.
Cavity surface treatment – It refers to a specialized process applied to the internal surfaces of a mould, die, or tool cavity (such as those used in injection moulding, die casting, or forging) to improve wear resistance, reduce friction, prevent thermal fatigue, and resist corrosion.
Cavity wall – It is a construction type made of two separate parallel walls, called leaves or wythes, separated by an empty or insulated air gap.
Cavity width – It is the horizontal distance between the two separate walls or ‘leaves’ which make up a cavity wall.
CBGuard – It is an advanced, X-ray-based continuous monitoring system for conveyors used to track the structural health and internal integrity of heavy-duty industrial conveyor belts in real time. It acts as an automated diagnostic tool that scans virtually every cubic millimeter of a moving belt to detect internal cord breakage, tears, and wear before failures occur.
C-circuit – It typically refers to an alternating current (AC) circuit containing capacitance only (a purely capacitive circuit), or it designates a component reference and layout tied to a capacitor (C).
C Content – It means carbon content. It refers to the percentage of carbon alloyed with iron to produce steel and cast iron. It is the main factor determining a metal’s mechanical properties.
C concrete – Concrete C refers to a composite material consisting of a binding matrix (cement paste) formed by mixing cement and water, combined with embedded particles known as aggregates, which can be either fine or coarse.
C-C coupling reactions – These refer to the processes which create carbon-carbon bonds, frequently facilitated by catalysts, such as those derived from metal-organic frameworks (MOFs), which improve reaction efficiency and allow for the coupling of various organic substrates in high yields.
CCT diagram – It is the continuous cooling transformation diagram. It is the set of curves drawn using logarithmic time and linear temperature as coordinates, which define, for each cooling curve of an alloy, the beginning and end of the transformation of the initial phase.
C-curve – It refers to a time-temperature-transformation (TTT) diagram. It is a plot which shows how a metal’s microstructure and properties change during continuous cooling or isothermal holding after being heated above its transformation temperature. Essentially, it shows the time it takes for a material to transform from one phase to another at different temperatures.
CD system It is also called continuous delivery or continuous system. It is an automated tool-chain which builds, tests, and prepares code changes for release into production.
CdTe crystals – These are semi-conductor materials made of cadmium (Cd) and tellurium (Te) which feature a cubic zinc-blende crystal structure and a direct energy band-gap ideal for converting light into electricity.
CdTe (cadmium telluride) thin film – It is a poly-crystalline semi-conductor layer, typically a few micrometers thick, composed of cadmium and tellurium, renowned for its near-ideal direct bandgap of around 1.45 electron volts to 1.5 electron volts (eV) and a very high optical absorption coefficient.
Ceiling hangers – These are steel rods affixed to the ceiling. They provide support for conveyors to maximize floor space or when floor support is insufficient.
Celestine – It is a mineral consisting of strontium sulphate (SrSO4). The mineral is named after its occasional delicate blue colour. Celestine and the carbonate mineral strontianite are the principal sources of the element strontium, normally used in fireworks and in several metal alloys.
Celestite – It is also known as celestine. It is a naturally occurring strontium sulphate mineral (SrSO4). It is the main commercial ore for the extraction of strontium and its derivatives, valued for its high density, thermal stability, and specific chemical reactivity.
Celgard – It refers to a brand of micro-porous poly-propylene fibres used in modules designed for concentration-driven mass transfer, which improves mass transfer coefficients through uniform fibre spacing.
Cell – It is the electro-chemical system consisting of an anode and a cathode immersed in an electrolyte. The anode and cathode can be separate metals or dissimilar areas on the same metal. The cell includes the external circuit, which permits the flow of electrons from the anode toward the cathode.
Cell array – It is a configuration of photo-voltaic cells connected either in series, to increase voltage, or in parallel, to increase current, forming a photo-voltaic generator which produces the desired output voltage and current for specific applications.
Cell average throughput – It is the total volume of data successfully transmitted or received across all active user equipments (UEs) in a wireless network cell or sector over a specific period, divided by that time duration. It is a key performance indicator (KPI) used to measure the overall data capacity and efficiency of a base station sector, rather than the speed experienced by a single user.
Cell bandwidth – It is the total range of frequencies allocated and deployed for wireless communication within a specific cellular network cell, measured in hertz.
Cell, battery – Battery cell is the single, basic electro-chemical unit that stores chemical energy and converts it into electrical energy.
Cell block – It is an internal microstructural sub-division of a deformed grain consisting of groups of smaller dislocation cells bounded by boundaries with higher misorientation angles.
Cell block boundaries – These are high-misorientation interfaces which divide plastically deformed grains into distinct structural regions with different active slip systems.
Cell, button – Button cell is a small, flat, single-cell battery shaped like a squat cylinder which provides reliable power for compact electronic devices.
Cell-edge user – It is a user equipment (UE) located near the outer boundary of a base station’s coverage area, where signal strength is weakest and interference from neighbouring cells is highest.
Cell, electro-chemical – Electro-chemical cell is a system which converts chemical energy into electrical energy or uses electrical energy to drive non-spontaneous chemical reactions.
Cell, fuel – Fuel cell is an electro-chemical device which converts the chemical energy of a fuel directly into electricity and heat without combustion.
Cell interconnectors – These are physical and electrical components which transfer electrons, current, and power between individual cells, such as in fuel cells, batteries, or solar modules, while providing structural separation or gas distribution.
Cell interference – It is the degradation of signal quality in mobile cellular networks caused by the use of the same or adjacent resources in neighbouring cells, which can limit overall network performance and affect edge users. It encompasses different types, including inter-cell interference, co-channel interference, and adjacent channel interference.
Cell, multi – Multi cell refers to a transmission method which involves sending identical signals from multiple cell sites, synchronized in timing, to improve coverage and reduce inter-cell interference, effectively making the signals received at the terminal appear as if they originated from a single site.
Cell network – It is a type of connection-oriented packet network designed to support both continuous high-bandwidth data streams and bursty packet traffic, utilizing a simple protocol which enables fast operation. It involves a connection set-up process which can allocate resources for guaranteed transmission rates or allow statistical multiplexing among different connections.
Cell operation – It is the physical and chemical process where a device turns chemical energy into electrical energy. In production systems, cell operation means completing a full set of manufacturing steps in a single, compact work-space.
Cell performance – It is the operational efficiency, power output, and longevity of an electro-chemical or manufacturing cell (such as a fuel cell or battery cell) under specific load and environmental conditions.
Cell phone – It is a portable two-way radio telephone which communicates wirelessly through low-power radio waves through a network of geographic coverage areas called ‘cells’.
Cell potential – It is the force in a galvanic cell which pulls electrons through a reducing agent to an oxidizing agent.
Cell pressure – It refers to the operational pressure within a phosphoric acid fuel cell (PAFC), which improves cell performance by reducing diffusion losses, increasing the reversible potential, and minimizing activation polarization, ultimately improving ionic conductivity and exchange current density.
Cell, pressure – Pressure cell is a specialized sensor which converts physical stress or fluid pressure into a readable electrical output.
Cell scenarios – These scenarios refer to the conditions and interactions within multicell environments where multiple cells are in close proximity, influencing failure dynamics such as heat generation, thermal propagation, and electrical failures. These scenarios are characterized by the potential for a single cell failure to escalate and affect neighboring cells, leading to more severe outcomes than isolated cell events.
Cell search – It is the initial process for a user equipment (UE) to access 5G (fifth generation) services, involving frequency scanning, cell detection, and system information acquisition to identify and connect to an appropriate cell.
Cell series – It is a configuration in which battery cells are connected in a sequence to meet higher voltage requirements, normally combined with parallel arrangements to improve capacity. This topology influences factors such as stability and load distribution during operation.
Cell size – It is the diameter of an inscribed circle within a cell of honey-comb core.
Cellular automata – It is a computational method which uses a grid of discrete cells to simulate how a metal’s internal microstructure changes over time and space.
Cellular automata (CA) method – It is a discrete computational modelling technique used to simulate how a metal’s internal micro-structure, such as grain size, shape, and phase distribution. evolves over space and time during processes like solidification, recrystallization, and phase transformation.
Cellular automaton model – It is a discrete dynamical system where a grid of cells evolves in steps based on local rules governing the states of neighbouring cells. Cellular automaton (CA) models simulate complex spatial and temporal phenomena, such as material micro-structure evolution, traffic flow, and fluid dynamics, by applying simple local interactions to capture macro-level system behaviour.
Cellular glass – It is a lightweight, rigid, and inorganic thermal insulation material made from crushed glass mixed with a foaming agent and heated until it expands into millions of completely sealed, airtight glass cells. It is also normally known as foam glass or expanded glass.
Cellular glass insulation – It is a rigid, lightweight thermal insulation material made from millions of completely sealed, gas-filled glass cells. It is made from crushed or recycled glass mixed with a foaming agent like carbon or limestone, then heated until it forms a closed-cell structure.
Cellular infrastructure – It is the physical and logical framework of radio towers, antennas, and core network systems which divides a geographic region into ‘cells’ to provide wireless mobile communication.
Cellular manufacturing – It is a production approach which organizes work-stations and equipment into cells to facilitate the efficient processing of part families, focusing on short-term control and adaptability to changing customer demands. It involves techniques for cell formation and is evolving towards more integrated and flexible systems.
Cellular model – In computer-aided design (CAD), a cellular model is a geometric representation of an object using spatial cells or volumetric elements rather than traditional boundary surfaces.
Cellular modelling – It refers to creating mathematical or computational representations of spatial geometric subdivisions to simulate physical systems.
Cellular network – It is a distributed radio communication system which divides a large geographic region into smaller sections called ‘cells’, using fixed-location base stations to connect mobile devices wirelessly.
Cellular plastic – It is a plastic containing numerous cells, inter-connecting or not, distributed throughout the mass. It is also called expanded plastic or foamed plastic.
Cellular solids – These are materials composed of interconnected networks of solid struts or beams which form the edges and faces of cells, showing a structure which can be either open cell or closed cell.
Cellular telecommunications – It is a wireless communication system which divides a large geographic area into smaller sections called ‘cells’, each served by a fixed low-power base station or transceiver.
Cellulose coating – This type of electrode coting provides a gaseous shield with a reducing agent in which the gas shield surrounding the arc is produced by the disintegration of cellulose.
Cellulose ether – It is a water-soluble polymer created by chemically modifying natural plant cellulose. It serves as a vital chemical additive which controls fluid properties, retains moisture, and improves material consistency.
Cellulose insulation – It is a thermal insulation material made from recycled paper or wood fibre mass, frequently improved with boric acid and borax to improve its properties. It serves as a filler material for cavities and spaces, with thermal conductivity values typically ranging from 40 milliwatts per meter-Kelvin to 50 milliwatts per meter-Kelvin, which can vary with temperature, moisture content, and mass density.
Cell voltage – It is the electrical potential difference between the two electrodes of an electro-chemical cell.
Cell voltage measurement – It is the process of quantifying the electrical potential difference between the positive and negative electrodes of an individual battery cell or electro-chemical unit.
CE marking – The CE (Conformite Europeenne) marking is a mandatory European marking for certain product groups placed on the European Economic Area (EEA) to indicate conformity with the essential health and safety requirements set out in European Directives. To permit the use of a CE mark on a product, proof that the item meets the relevant requirements must be documented.
Cement – It is a substance (frequently a ceramic) which by chemical reaction binds particulate aggregates into a cohesive structure. With hydraulic cements the chemical reaction is one of hydration, involving water. There are several types of cements. In construction, the term cement normally refers to bonding agents which are mixed with water or other liquid, or both, to produce a cementing paste.
Cement admixtures – These are compounds which are added to cementitious systems to optimize properties such as fluidity, strength, and durability, allowing for a broader range of performance in concrete formulations.
Cementation – It is the introduction of one or more elements into the outer portion of a metal object by means of diffusion at high temperature.
Cementation exponent – It describes how the electrical formation factor of a porous rock relates to its porosity. It is a parameter which describes the relationship between the formation factor and porosity in a porous medium, typically determined through regression analysis of intrinsic formation factor and porosity data. It can be calculated using bi-logarithmic regression methods, similar to the Archie cementation exponent.
Cementation steel – It is a chromium nickel steel with 0.15 % carbon.
Cement-based materials – These are composite construction products made from a hardened paste of hydraulic cement and water mixed with other components like sand, gravel, or fibres.
Cement-bonded pellet process – It is a cold-agglomeration method which uses hydraulic binders like Portland cement to turn fine powders, industrial wastes, or iron ore fines into solid spherical pellets without high-temperature firing.
Cement by-pass dust – It is a fine-grained, highly alkaline waste by-product captured from the exhaust and gas bypass systems of rotary kilns during Portland cement manufacturing. It when added to road pavement layers, improves their characteristics by filling voids, increasing density, and improving binding properties, hence contributing to the overall durability of the pavement.
Cement chemistry – It is the study of the chemical compositions, manufacturing reactions, and hydration processes of hydraulic binders which allow cement paste to set, harden, and retain stability in construction.
Cement clinker – It is a hard, nodular intermediate product made by heating limestone and clay in a rotary kiln at temperatures around 1,400 deg C to 1,500 deg C.
Cement clinker production – It is the process of heating blended raw materials, mainly limestone and clay, in a rotary kiln to form hard, dark-grey nodular intermediate materials. The process involves substantial energy consumption which can be optimized through techniques such as using alternative fuels and waste heat recovery.
Cement column -It is a reinforced cement concrete (RCC) column. It is a vertical structural element designed to support compressive loads by transferring weight from slabs and beams down to the foundation.
Cement components – These refer to the individual raw materials, chemical oxides, and microscopic mineral compounds that make up cement and give it its binding and hardening properties. These are the individual materials, such as clinker, blast furnace slag, and fly ash, which make up the chemical and mineralogical composition of cement, which can vary considerably even among cements of the same type.
Cement composite – It is a multi-phase material created by combining a hydraulic cement binder with distinct reinforcing elements, such as fibres, polymers, or aggregates, to overcome the inherent brittleness and low tensile strength of traditional cement.
Cement concrete – It is a composite material composed of cement, aggregates (such as sand, gravel, and crushed rock), and water, where cement acts as the main binder which hardens through hydration reactions, providing strength and a stone-like quality capable of bearing high compressive loads.
Cement constituents – These constituents refer to the different materials used in the composition of cement, including clinker, blast-furnace slag, natural pozzolans, fly ashes, limestone filler, silica fumes, and calcium sulphate, which together influence the properties of the resulting cementitious materials.
Cement content – It is the absolute quantity of cement used in a specific volume of concrete, normally measured in kilograms per cubic meter. It defines how much dry binding powder is present per unit volume of the fresh concrete mix.
Cement copper – It is the impure copper recovered by chemical deposition when iron (very frequently shredded steel scrap) is brought into prolonged contact with a dilute copper sulphate solution.
Cement dust – It is a fine-grained particulate by-product and airborne pollutant generated during the crushing, grinding, manufacturing, handling, and application of cement and concrete. It consists of a complex mixture of unreacted raw materials (calcium carbonate, quartz), partially calcined feed, and cement clinker particles containing oxides of calcium, silicon, aluminum, iron, and magnesium.
Cemented carbide – It is a solid and coherent mass made by pressing and sintering a mixture of powders of one or more metallic carbides, such as tungsten carbide, and a much smaller quantity of a metal, such as cobalt, to serve as a binder.
Cemented doublet – It is a type of lens composed of a positive crown glass element cemented to a concave flint glass element, designed to correct chromatic aberration and maintain a constant focal length at two selected wave-lengths, typically in the red and blue regions of the spectrum.
Cemented tungsten carbide – It is a hard composite material made of tungsten carbide particles ‘cemented’ together by a metallic binder like cobalt. This material is created using powder metallurgy techniques rather than traditional melting and casting, since pure tungsten carbide has an extremely high melting point and is too brittle on its own.
Cement grain – It is an individual microscopic particle of anhydrous cement powder, typically ranging from 1 micrometer to 100 micrometers in size, which reacts with water to form the binding gel in concrete.
Cement grout – It is a fluid, pumpable mixture of Portland cement, water, and frequently fine sand or additives designed to flow into narrow gaps, cracks, and subsurface voids. It is made from hydraulic cement, clean water, and fine aggregate (sand) with a grain size typically under 2 millimeters. It has a higher water content and thinner viscosity than standard concrete, allowing it to act as a liquid shim or permeate tiny spaces. It hardens through chemical hydration to lock structures in place and transfer loads.
Cement hydration reaction – It is the exothermic chemical process which occurs when water is added to cement, leading to the setting and hardening of the mix through different reactions which release heat. This process encompasses heat evolution from the wetting, dissolution, ion hydration, crystallization, and formation of new hydrates.
Cementing operation – It is the process of mixing a cement slurry and pumping it down through a steel casing into the annulus (the space between the casing and the underground rock formation) to secure and seal the well-bore.
Cementite – It is a hard (800 Vickers hardness, HV), brittle compound of iron and carbon, known chemically as iron carbide and having the approximate chemical formula Fe3C. It is characterized by an orthorhombic crystal structure. When it occurs as a phase in steel, the chemical composition is to be altered by the presence of manganese and other carbide-forming elements. The highest cementite contents are observed in white cast irons, which are used in applications where high wear resistance is needed.
Cementite plates – These are iron carbide (Fe3C) plates. These are microscopic, plate-like or lamellar structures of iron carbide which form inside iron-carbon alloys like steel and cast iron.
Cementitious binder – It is an inorganic material which mixes with water, hardens through a chemical process called hydration, and binds aggregates together to form strong construction materials like concrete and mortar. Cementitious binder materials are widely used for conditioning and disposal of low-level and intermediate-level waste.
Cementitious component – It is a binding material which reacts with water through a process called hydration to set, harden, and glue construction aggregates together. Cementitious components refer to materials which can bind together to form cementitious composites, which are necessary for construction. These components frequently include traditional materials like Portland cement, as well as alternative materials sourced from solid waste, contributing to durability and performance while addressing waste management issues.
Cementitious composites – These are high-performance building materials created by combining a cement paste binder with aggregates and microscopic fibres to fix the structural weaknesses of normal concrete.
Cementitious materials – These materials are binding materials, mainly composed of complex-bonded mixtures of calcium silicates or calcium hydroxides, which react with water to produce hydration products for use in construction. These include commercial cements like Portland cement and can incorporate different supplementary materials such as fly ash to improve performance and sustainability.
Cementitious matrix – It is the binding material typically made from Portland cement, water, and sometimes fine aggregates which hardens to hold solid particles, fibres, or reinforcing fillers together in a composite.
Cementitious mix – It is a composite construction material where hydraulic binders like Portland cement chemically react with water (hydration) to bind aggregates (like sand, gravel, or crushed stone) into a solid, durable mass.
Cementitious mortar – It is a workable paste made from cement, fine aggregate (sand), and water which hardens to bind building blocks like bricks and stones.
Cementitious system – It is a combination of finely divided hydraulic binding materials (like Portland cement) and reactive mineral admixtures that react chemically with water to form a solid, durable binder.
Cementitious waste – It refers to a type of immobilized low-level and intermediate-level radioactive waste (LILW) which utilizes cement-based matrices to encapsulate and stabilize the waste, minimizing the leaching and migration of radio-nuclides into the environment. These matrices are characterized by their mechanical strength, low permeability, and long-term durability, achieved through hydration processes and micro-structure development.
Cement kiln – It is a massive, inclined rotating furnace used to pyrolyze and transform raw materials, mainly a mix of limestone and clay, into cement clinker at temperatures reaching up to 1,450 deg C.
Cement kiln dust – It is a fine-grained, highly alkaline by-product collected from exhaust gases during the manufacturing of Portland cement clinker.
Cement matrix – It is the continuous binding phase in a cement matrix composite (like mortar or concrete) which holds aggregates, fibres, or functional fillers together. It is formed by mixing hydraulic cement (such as ordinary Portland cement) with water, which then hardens through a chemical process called hydration. It acts as a colloidal gel-like binder. Its most important strength-giving product is the calcium-silicate-hydrate (C-S-H) gel at the microscopic scale.
Cement mixing – It is the process of combining cement, water, fine aggregates like sand, and coarse aggregates like gravel or crushed stone to create a uniform, workable paste or concrete. When water is added, it triggers a chemical reaction called hydration, transforming the dry cement into a strong binding agent which hardens into a solid mass.
Cement mixture – It is a composite combination of hydraulic cement, water, fine and coarse aggregates, and optional admixtures which reacts chemically to form a solid, rock-like mass.
Cement mortar – It is a workable paste made of cement, fine aggregate (such as sand), and water, used in construction to bind building blocks like bricks and stones together.
Cement moulding – It is the process of shaping wet cement, mortar, or concrete inside a designed form or container until it hardens. This technique creates strong structural parts, or pre-cast building components.
Cement particle – It is a discrete, microscopic unit of ground hydraulic binder which reacts chemically with water to form the binding matrix of concrete and mortar.
Cement paste – It is a binding mixture of portland cement and water which undergoes a chemical reaction to glue aggregates together in concrete.
Cement phase – It refers to a distinct chemical or mineral compound formed during the manufacture of cement clinker which dictates how the material sets, hardens, and performs.
Cement pipe – It is normally referred to as a concrete pipe. It is a rigid cylindrical conduit made from a mixture of Portland cement, water, fine sand, and coarse aggregates, designed to support heavy external loads while transporting water, sewage, or storm drainage. Unlike flexible pipes made of plastic or metal which need tight side-fill soil support to avoid bending, a concrete pipe has its own built-in structural strength. This rigidity lets it carry heavy traffic and deep earth loads safely.
Cement plant – It is a facility which transforms raw materials like limestone, clay, and shale into hydraulic cement through pyro-processing and mechanical grinding. The facility integrates mechanical, thermal, and process-control systems into a continuous production line.
Cement pore solution – It is the liquid phase trapped inside the tiny spaces and capillaries of hydrating or hardened cement paste and concrete. It is the aqueous phase present within cement paste, influencing the hydration process and phase assemblage of cement, particularly in the presence of additives such as limestone.
Cement production – It refers to the process of manufacturing cement, which mainly involves the production of clinker from limestone followed by the mixing of clinker with other materials. This process is highly energy-intensive and considerably contributes to global energy consumption and carbon di-oxide (CO2) emissions.
Cement ratio – It is the water-cement ratio, which is the weight of water divided by the weight of cement used in a concrete mix.
Cement, refractory – Refractory cement (or high-alumina / calcium-aluminate cement) is a specialized hydraulic binder formulated to retain its structural integrity, strength, and chemical resistance at extreme temperatures ranging from 1,100 deg C to over 1,800 deg C, where ordinary Portland cement structurally degrades.
Cement replacement material – It refers to materials used to partially substitute cement in concrete to reduce costs or improve properties, which can be incorporated through methods such as direct replacement or addition.
Cement sample – It is a prepared sample of cement paste, mortar, or grouting moulded into a specific shape and size to test and evaluate the physical, chemical, and mechanical properties of the material.
Cement silo – It is a large, sealed vertical container used to safely store dry, bulk powdered materials like cement, lime, and fly ash.
Cement slurry – It is a pourable, watery mixture made of cement, water, and specialized chemical additives.
Cement stabilization – It is a geotechnical technique which mixes Portland cement, water, and natural soil to form a hardened, durable structural material known as soil-cement.
Cement-stabilized soil – It is a mixture of local in-situ soil, water, and Portland cement which cures into a semi-bound or bound material with high strength and durability. Also known as soil-cement, it binds loose soil particles together through a chemical hydration process.
Cement surface – It typically refers to either the exposed outer boundary of hardened cement-based materials or the specific surface area of finely ground cement particles.
Cement suspension – It refers to the mixtures where cement particles are dispersed in a liquid medium, characterized by high ionic strength, making stabilization through electro-static repulsion challenging. Instead, steric repulsion plays an important role in their stability, particularly at full surface coverage.
Cement sustainability initiative – It is a collaborative effort led by the World Business Council for Sustainable Development (WBCSD) aimed at promoting sustainability within the global cement industry, focusing on reducing carbon emissions, improving energy efficiency, and promoting sustainable supply chains throughout the cement production life-cycle.
Cement-treated base – It is a strong, durable foundation layer for roads and pavements made by mixing native soils or aggregates with measured quantities of portland cement and water.
Cement treatment – It is the process of mixing soil, aggregates, or waste materials with a small quantity of portland cement and water to improve their physical strength, durability, and load-bearing capacity.
CEN (Comite Europeen de Normalisation) – It is also known as European Committee for Standardization. It is the body responsible for developing European Standards, frequently referred to as ‘Euro-Norms or EN for short.
Cenospheres – These are defined as free-flowing, hollow spheres collected from coal ash, characterized by a low density, high strength, and amorphous structure, chiefly composed of silica (SiO2) and alumina (Al2O3). These are used in different industrial applications, particularly in construction, as light-weight aggregates and fillers because of their advantageous physical properties.
Censored cases – In survival analysis, these are cases with incompletely observed survival times. Right censoring occurs when the subject has not yet experienced the event by the end of the observation period. Left censoring occurs when subjects have already experienced the event by the beginning of observation.
Censored distribution – It is a frequency distribution of observations which have either a lower or upper cut-off. For example, fatigue tests which are stopped unbroken after 106 cycles represent a censored frequency distribution.
Centered binomial distribution – It is a discrete probability distribution with a mean of zero, formed by subtracting one set of independent random binary values from another.
Centered cubic metal – It is normally known as a body-centered cubic (BCC) metal. It is a metal whose atoms are arranged in a crystal structure with one atom at each of the eight cube corners and one single atom right in the centre of the cube’s body.
Centered cubic structure – It very frequently known as a body-centered cubic (BCC) structure. It is a crystal lattice arrangement where one atom sits at each of the eight corners of a cube and one single atom sits directly in the exact centre of the cube.
Centered maintenance – it means reliability-centered maintenance (RCM). It is a structured process used to figure out the best maintenance strategy for physical equipment based on its specific operating context.
Centering arms – These are externally mounted guide rolls or mechanical arms / hydraulic arms used during the ring rolling process to keep a metal ring blank aligned and concentric on the mill.
Centering rolls – These are specialized mechanical guide components used in metal rolling and processing mills to keep a work-piece, strip, or ring precisely aligned along the central axis of the machine.
Centimeter – It is a unit of length in the metric system equal to one-hundredth of a meter.
Centistoke (cSt) – It is a unit of kinematic viscosity. It is a measure of how easily a fluid flows. It is equal to one hundredth of a stoke (St) and is widely used in scientific and engineering contexts.
Central alignment – It is also referred to as centre-line alignment. It is the fundamental reference line or geometric path representing the absolute centre of a design feature, object, or system. It serves as a master layout guide to ensure structural balance, symmetry, and precise dimensioning across manufacturing, civil projects, and mechanical systems.
Central axis – It is a real or imaginary straight line which runs through the exact centre of an object, shape, or space.
Central boom – It is a loader or excavator arm mounted directly down the middle of the machine’s frame, rather than offset to one side.
Central boss – It is a raised, circular protrusion or pad on a metal casting or forged component, frequently located centrally to serve as a mounting point, reinforcement, or housing for a hole.
Central burst – It is also known as a chevron defect. It is an internal fracture which occurs along the central axis of a metal bar, wire, or extruded product during metal-forming processes like drawing or extrusion.
Central composite design – It is also known as a Box-Wilson central composite design. It is a specialized statistical experimental design used in ‘response surface methodology’ to build a second-order quadratic model for a response variable without requiring a full three-level factorial experiment.
Central computer system -It is the top level of the control system and has databases of the whole plant, which is obtained by collecting and stocking information of the subordinate computers. It uses the databases in the elaboration of the planning of material purchasing and production, as well as in the production report and technical analysis of the production data.
Central concentrated load – It is a force applied directly at the exact midpoint (centre) of a structural member like a beam.
Central controller – It is the main decision-making device or software node in a centralized system which manages, coordinates, and directs all subordinate devices or processes from a single location.
Central control room – It is a secure, dedicated hub where operators use real-time data, video displays, and communication tools to monitor and manage complex systems or physical facilities.
Central core – It is the middle and most important section of an object, system, or idea. Examples include the deep interior of a planet, or the fundamental foundation of a concept or project.
Central crack – It is also called centre-line crack. It is a fracture or separation defect which forms in the exact middle or core of a structural material, component, or cast metal slab.
Central deflection – It is the maximum vertical displacement or distance which the mid-point of a structural member (such as a beam or panel) moves from its original, unloaded position when subjected to external loads. It depends on the applied load, the length or span of the member, the material’s stiffness (Young’s modulus), and the cross-sectional shape (moment of inertia).
Central fibre – It is the innermost core component of a fibre optic cable which transmits light signals.
Central frequency – It is defined as the specific frequency at which an oscillator operates, characterized in the source as 94 giga-hertz for the described voltage-controlled oscillator (VCO), which can be tuned from 91.8 giga-hertz to 96.5 giga-hertz.
Central fuel jet – It is the main nozzle or orifice located along the centre-line of a burner, combustion chamber, or carburetor which injects a continuous or metered stream of liquid or gaseous fuel into an air-flow or oxidizer co-flow.
Central heater – It is a single installation which warms an entire building or multiple rooms from one main heat source.
Central heating system – It is a method which provides warmth to the entire interior of a building or portions of it from a single point, typically using a central boiler or furnace to generate heat, which is then distributed through pipes or ducts to different rooms.
Centralized architecture – It is a system where all nodes are connected to a central coordination system which facilitates information sharing. However, it is vulnerable to failure as the entire network can become inoperative if the central system fails.
Centralized control – It is a systems architecture where a single central controller, node, or computer holds total decision-making authority over all subordinate elements, devices, or processes.
Centralized controller – It is a control mechanism which manages SDN (software-defined networking) -enabled sensor nodes from a single location within a network, coordinating the control and data planes through communication protocols. This approach, while straight-forward, has limitations such as a single point of failure and potential congestion, particularly in larger networks.
Centralized control system – It is an architecture where a single, central unit handles all data processing, decision-making, and command issuance for an entire network or machine.
Centralized graphical user interface – It is a single, unified visual control panel used to monitor, configure, and operate complex systems, machinery, or software from one master location.
Centralized management – It is a structural and control framework where decision-making authority, system configurations, and resource coordination are concentrated within a single primary node, master controller, or upper-level engineering team.
Centralized network – It is an architecture where all nodes connect to a single central server or authority which handles all communications, data storage, and processing.
Centralized scenario – It is a model or operational framework where planning, decision-making, power, and core resources are concentrated in a single, central authority or location rather than distributed across multiple regions or lower-level units. Its core characteristics are top-down flow, standardization, and single point of control.
Centralized tool adjustment (CTA) system – It refers to a control architecture where the physical geometry, calibration, positioning, or wear metrics of manufacturing tools are monitored and adjusted from a single, centralized system or algorithmic unit rather than relying on decentralized, manual operator changes at individual machine stations. It is an automated system that collects physical measurement metrics from inline coordinate measuring machines (CMMs) or digital sensors, feeds that data back to a centralized algorithm, and automatically pushes tool wear offset corrections back to multiple computer numerical control (CNC) machine tools.
Centralized torque anchor – It is a downhole oilfield tool used to anchor a tubing string and a progressive cavity pump (PCP) inside the well casing, preventing the tubing from rotating or backing off.
Central jet – It is a stream of fluid, gas, or particles which flows directly through the middle or centre of a defined opening, channel, or system rather than along the edges.
Central limit theorem – It states that the distribution of sample means approaches a normal (bell-shaped) distribution as the sample size gets larger, no matter what the shape of the original population distribution looks like. Central limit theorem’s result explains why the normal distribution is so important in statistics. Frequently, it is desired to use the sample mean ‘x’ to estimate the mean, ‘mu’, of the population. The central limit theorem says that, as long as the sample size is reasonably large, the distribution of ‘x’ about ‘mu’ is roughly normal, whatever the distribution of the data.
Central management – It is the practice of controlling, monitoring, and coordinating systems, data, or projects from a single, unified location or authority.
Central moment – It is a statistical measure which describes the shape and spread of a probability distribution or dataset by calculating the expected value of the deviations from the mean raised to an integer power. Unlike raw moments (which measure distance from zero), central moments measure distance from the mean. This ensures that higher-order values focus entirely on how data is spread out or shaped, rather than where it is located on the number line.
Central node – It is the main, primary component in a network which links all surrounding devices or points, and handles processing, managing, and routing data.
Central office – It is either the main administrative headquarters of an organization or a physical telecommunications facility where local phone and data lines converge to route calls and network traffic. It is the main building where the organization directs its management, core decisions, and daily operations.
Central plant – It is a centralized facility or dedicated area within a building complex which houses major mechanical equipment to generate and distribute utilities like heating, cooling, and electricity.
Central processing unit – It is also called a central processor, main processor, or just processor. It is the most important processor in a computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input / output (I/O) operations. Principal components of a CPU (central processing unit) include the arithmetic-logic unit (ALU) which performs arithmetic and logic operations, processor registers which supply operands to the arithmetic-logic unit and store the results of arithmetic-logic unit operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the arithmetic-logic unit, registers, and other components. Majority of the modern central processing units are implemented on integrated circuit (IC) micro-processors, with one or more central processing units on a single integrated circuit chip. Micro-processor chips with multiple central processing units are called multi-core processors.
Central processor – It is the main hardware component of a computer which interprets and executes programme instructions. Frequently called the ‘brain’ of the computer, it performs basic arithmetic, logical, control, and input / output operations specified by software.
Central receiver system – It is also known as a solar power tower. It is a type of concentrated solar power plant which uses a field of tracking mirrors to focus sunlight onto a single receiver mounted on top of a central tower.
Central ridge – It refers to a signal in the FORC (first-order reversal curve) diagram which appears as a delta function along the ‘Hc’ axis, associated with the symmetrical irreversible switching of a collection of randomly oriented identical particles.
Central rod – It is a structural, or mechanical component located along the middle axis of an object, or system. It typically serves as a core support, a guide for movement, or a point of connection for surrounding parts.
Central stack – It is the unified, standardized combination of technologies used to build and run an organization’s main applications. Central stack in computer architecture is a dedicated area of system memory controlled by the ‘stack organization’ register which handles temporary data, return addresses, and local variables using a last-in, first-out (LIFO) method.
Central stop – It is a centralized safety switch designed to immediately halt all moving parts or remove electrical power across an entire machinery line. Rather than stopping just one component, triggering the central stop initiates a system-wide stop category 0 or 1 safety routine to prevent injury or mechanical failure. In physical design and manufacturing, central stop is a structural protrusion or ridge built into the exact middle of a component to restrict travel or align parts. In optics, a central stop is an aperture stop or physical blocker placed directly along the optical axis (the centre) of a lens or imaging system. It is used for two main purposes namely symmetrical lens layouts, and phase visualization and X-ray filtering.
Central tendency of data – In statistics this is described by the central limit theorem. This theorem states the fact that if one draws samples of size ‘n’ from the population and calculates the mean of these samples, the means forms a distribution which tends toward normality regardless of the form of the original sample distribution.
Central upsetting – It is a forging operation where only the middle section of a metal work-piece is heated and compressed lengthwise to increase its thickness and diameter locally.
Central void – It refers to a hollow space, cavity, or piercing located at the geometric centre of a structural element, manufactured component, or solidified material.
Central wave-length – It is the designated reference or middle wave-length where an optical device, filter, or laser system primarily operates or achieves peak transmission.
Centre – It refers to the centroid and centres of gravity of an object, representing a specific point of balance, symmetry, or mass concentration. It is also the difference in thickness between the middle and edges (average) of a sheet.
Centre brick – It is a special, hollow, refractory shape used at the base of the guide tubes in the bottom pouring of molten steel. The centre brick has a hole in its upper face, and this is connected through the hollow centre of the brick to holes in the faces (frequently six in number). The centre brick distributes molten steel from the trumpet assembly to the lines of runner bricks. It is also sometimes known as a crown brick or spider.
Centre buckle – It is bulging of a large, flat face of a casting. In investment casting, it is caused by dip coat peeling from the pattern. It is an indentation in a casting, resulting from expansion of the sand, and can be termed the start of an expansion defect. It is also a local waviness in metal bar or sheet, normally transverse to the direction of rolling.
Centre burst – It is also known as chevroning. It is an internal metal defect characterized by a series of V-shaped or chevron-like internal cracks along the centre-line of extruded, drawn, or forged metal products.
Centre drilling – It consists of drilling a short, conical hole in the end of a work-piece. It is a hole to be used to centre the work-piece for turning on a lathe.
Centre drive – It is a drive assembly typically located beneath, frequently at the centre of the conveyor, but adaptable to different positions in the conveyor length. It is normally used in applications involving reversing or incline movement.
Cent reduction – It is a common shorthand for percent reduction. It quantifies the efficiency or physical deformation of a process.
Centre frequency – It is the mid-point or central frequency between the lower and upper cut-off frequencies of a band-pass or band-stop system.
Centre-less grinding – It consist of grinding the outside or inside diameter of a cylindrical piece which is supported on a work support blade instead of being held between centres and which is rotated by a so-called regulating or feed wheel.
Centre line – It is a fundamental reference line which marks the axis of symmetry, centre point, or middle path of an object, feature, or structure.
Centre-line consolidation – It refers to the elimination of internal shrinkage cavities, micro-voids, and porosity located along the central axis of a cast ingot, bar, or heavy forging during hot mechanical working.
Centre-line deformation – It refers to the physical distortion, bulging, or shifting of the solidifying shell along the central axis of a cast metal strand (such as a slab, billet, or bloom) during continuous casting.
Centre-line feeding resistance – It is a term used in metal casting to measure how difficult it is for liquid metal to flow and fill the centre of a solidifying mould. Centre-line feeding resistance (CFR) is the percentage ratio of the time the centre of the casting spends solidifying compared to the total time it takes for the whole casting to solidify. ‘CFR = (freezing time at centre-line / total freezing time) x 100’.
Centre-line plane – It is an imaginary flat surface which bisects a symmetrical object or feature down its exact middle.
Centre-line porosity – It is a structural defect consisting of tiny voids, cavities, or pockets of trapped gas concentrated along the central axis or middle line of a cast metal, welded joint, or extruded plastic.
Centre-line radius – It is the distance measured from the exact centre point (curvature origin) of a bend to the central axis (centre-line) of a pipe, tube, or hose.
Centre-line segregation – It is a defect where impurities and alloying elements concentrate along the middle axis of a cast metal slab or billet during solidification.
Centre-line shrinkage – It is the porosity because of the incomplete fill after partial solidification of a casting (ingots or continuous-cast slabs or billets) or which occurs along the central plane or axis of a cast metal section.
Centre-line velocity – It is the speed of a fluid moving along the geometric centre (the central axis) of a pipe, duct, or jet flow.
Centre of a distribution – It is the typical or average value in a variable’s distribution.
Centre of gravity – Centre of gravity of an object is the point at which weight is evenly dispersed and all sides are in balance. It is the point around which the resultant torque due to gravity forces vanishes. Where a gravity field can be considered to be uniform, the mass-centre and the centre-of-gravity is the same.
Centre of gravity method – It is a mathematical technique used to find the best geographic location for a facility, such as a ware-house or distribution centre, which keeps total transportation costs and travel distances as low as possible.
Centre of gravity (CG) position – It is the exact balance point where the total weight of an object acts as if it has been concentrated in a single location.
Centre-plane – It is an imaginary middle plane which divides a symmetrical object, feature, or space evenly into two equal halves.
Centre point – It is the geometric middle of a shape or the average position of all points in an object.
Centre structure – It typically refers to the main core or central load-bearing framework of a complex assembly, building, or vehicle that absorbs main stresses and distributes loads.
Centre-to-centre – It is the distance between the centre of two pulleys. It is sometimes also called ‘centres’ or ‘centre distance’ or ‘conveyor length’.
Centre upsetting – It is the forming of upsets at some distance from the end. In centre upsetting, control of metal volume is normally very important, not only to prevent flash and tool overload but also to prevent folds.
Centric communication – It refers to a communication paradigm where data packets are explicitly routed between nodes or locators of topological significance, needing knowledge of the recipient’s address or the use of a resolution service to map identifiers to addresses. This approach is contrasted with more data-centric methods, such as publish-subscribe communications, which focus on the type of data communicated rather than the identities of individual nodes.
Centrifugal acceleration – It is the apparent, outward-directed acceleration experienced by an object or mass moving in a circular path when viewed from a rotating frame of reference.
Centrifugal atomization – It is a manufacturing process which uses centrifugal force from a rapidly rotating element, such as a disc or electrode, to break a stream of molten metal or liquid into fine, uniform droplets.
Centrifugal atomization process – It is a powder production process which uses mechanical centrifugal force from a rapidly rotating element (such as a disc, cup, or rotating consumable rod) to break a stream of molten metal into fine liquid droplets that then solidify into spherical metal powders.
Centrifugal casting – It is the casting which is made in moulds which are rotating so as to produce a centrifugal force in the molten metal. Centrifugal casting is also the process of filling moulds by (i) pouring metal into a sand or permanent mould which is revolving about either its horizontal or its vertical axis, or (ii) pouring metal into a mould which is subsequently revolved before solidification of the metal is complete. Horizontal centrifugal casting is used to produce rotationally symmetric parts, such as pipes, tubes, bushings, and other parts. Vertical centrifugal casting can be used to produce both symmetrical as well as non-symmetrical parts. However, since only a reasonable quantity of imbalance can be tolerated for a non-symmetrical part, the most common shapes produced are cylinders and rotationally symmetric flanged parts. Centrifugal casting of metal produces a finer grain structure and thinner ribs and webs than can be achieved in ordinary static mould casting.
Centrifugal casting machine – It is an industrial device which spins a permanent mould at high speeds (300 revolutions per minute to 3,000 revolutions per minute) while molten metal is poured into it. It uses centrifugal force instead of pressure or gravity to press the liquid metal against the mould walls. Two types of centrifugal casting machines are horizontal centrifugal casting machine and centrifugal casting-pipe machine.
Centrifugal casting process – It is a manufacturing process which uses the force generated by a rotating mould to distribute molten metal evenly against the mould walls and form hollow, symmetrical parts.
Centrifugal classifier – It utilizes centrifugal forces in a similar way to cyclones to induce fine particle separation. The classifier is capable of separations in the range of 100 micrometers to 15 micrometers. The classifier has widespread acceptance in industrial minerals, cement and fly ash applications. It has high degree of separation accuracy and exceptionally low maintenance requirements. The classifier is used in conjunction with a dust collector and system fan.
Centrifugal compressor – It is a type of dynamic compressor which increases the pressure of a gas by accelerating it with a rotating impeller and then converting this kinetic energy into pressure through a diffuser. It is used in several industrial applications to move and compress gasses, such as air, natural gas, and refrigerants.
Centrifugal compressor stage – It is a single compression element consisting of one rotating impeller paired with its associated stationary components (such as an inlet, diffuser, and return channel or volute) which together add energy and increase the pressure of a gas.
Centrifugal contactor – It is a high-efficiency chemical engineering device which uses rapid rotation to mix two immiscible liquids and separate them using centrifugal force instead of gravity.
Centrifugal discharge elevators – In this elevator, the buckets are spaced at a regular pitch to avoid interference in loading and discharging. The charging of buckets is by scooping action and the discharge is by centrifugal action. These elevators are normally used in vertical configuration and used for practically all types of free flowing, small lump materials like grain, coal, sand, clay, sugar, dry chemicals etc. Both belt and chain can be used and the speed of these elevators range between 1.1 metres per minute to 2 metres per minute.
Centrifugal extractor – It is a high-speed mechanical device used to mix two immiscible liquids and separate them rapidly using centrifugal force instead of gravity.
Centrifugal fans – These fans increase the speed of an air / gas stream with a rotating impeller. The speed increases as the air / gas reaches the ends of the blades and is then converted to pressure. These fans are capable of generating high pressures, which makes them suitable for harsh operating conditions, such as systems with high temperatures, dirty air / gas streams (high moisture and particulate content), and material handling. The centrifugal design uses the centrifugal force generated by a rotating disk, with blades mounted at right angles to the disk, to impart movement to the air or gas and increase its pressure. The assembly of the hub, disk, and blades is known as the fan wheel, and frequently includes other components with aerodynamic or structural functions.
Centrifugal force – It is an apparent outward force experienced by an object or fluid moving in a circular path, directed away from the axis of rotation.
Centrifugal impeller – It is a rotating rotor with curved blades housed inside a pump or compressor which converts mechanical drive energy into fluid velocity and pressure.
Centrifugal layering – It is normally known as sample layering in density gradient centrifugation. It is the process of placing a liquid sample in a thin, distinct zone on top of a pre-formed density gradient medium inside a centrifuge tube before spinning.
Centrifugally cast pipe – It is a cylindrical metal, concrete, or plastic pipe manufactured by pouring molten or liquid material into a rapidly spinning mould, using centrifugal force to distribute and press the material evenly against the outer mould wall until it solidifies.
Centrifugally cast rolls – The composition of centrifugally cast rolls is more or less similar to that of double poured rolls. First, metal which gives high hardness and better wearing properties is poured in the mould, which is then revolved at high speed. After sometime, molten metal of different composition is poured in for the core of the roll to make the core tougher. These rolls are superior to double poured rolls as the shell portion is denser giving better properties. The centrifugally cast rolls are also known as duplex rolls.
Centrifugally cast spun pipe – It is a cylindrical pipe manufactured by pouring molten metal or concrete into a rapidly rotating cylindrical mould, using centrifugal force to evenly distribute and compact the material against the mould walls.
Centrifugal nozzle – It is also referred to as a rotary atomizer or spinning disc nozzle. It is a mechanical device which utilizes centrifugal force and rotational energy to break down a continuous liquid stream into a fine mist of droplets, a process known as atomization. Unlike standard pressure nozzles which force liquid through a tiny orifice using high-pressure pumps, a centrifugal nozzle relies on a high-speed rotating component to fling the liquid outward.
Centrifugal pumps – These pumps operate by applying a centrifugal force to fluids. These pumps use the centrifugal force imparted to the fluid by one or more rotating elements (impellers) to increase the kinetic and pressure energy of the fluid. These pumps produce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller. Centrifugal pumps comprise radial, semi-axial and axial pumps, but also side channel, peripheral and liquid-ring pumps whose working principles are fundamentally different from that of the first group.
Centrifugal rubber mould casting – It is also known as spin casting. It is a manufacturing process which uses centrifugal force to force liquid metal or plastic into a flexible rubber mould.
Centrifugal separation – It is a process which uses rapid rotation and centrifugal force to separate components of a mixture based on differences in density.
Centrifugal separator – It is a mechanical device which uses rotational and centrifugal force to separate components of heterogeneous mixtures of different densities, such as solids from liquids or immiscible liquids from one another.
Centrifugal stiffness – It is also known as centrifugal stiffening. It is the increase in a rotating structure’s resistance to bending or deflection caused by tensile forces generated by rotation.
Centrifugal stress – It is the internal tensile stress induced in a rotating component (such as a turbine blade, flywheel, or compressor disk) by the outward inertial body forces of its mass during circular motion.
Centrifugation – It is a laboratory technique which involves the application of centrifugal force to separate particles from a solution as per their size, shape, and density. Larger and / or denser substances migrate away from the axis of a centrifuge, while smaller and /or less dense substances migrate towards the axis.
Centrifuge – It is a device used to separate substances based on size, shape, and density by centrifugation, or the rotation of vessels containing the substances around a centred axis at extremely high velocities.
Centrifuge casting – It is a casting technique in which mould cavities are spaced symmetrically about a vertical axial common down-gate. The entire assembly is rotated about that axis during pouring and solidification.
Centrifuge, separator – Separator centrifuge is a mechanical device used in industrial processes to separate liquid mixtures, suspensions, and sludges into their distinct components, mainly through solid-liquid separation. It operates by utilizing centrifugal force to improve the sedimentation of particles.
Centrifuge testing – It is a method where parts assembled with adhesives are subjected to centrifugal force in a spinning test chamber to assess die and substrate adhesion, typically performed to a known ‘G’ load or until failure occurs. It is widely used as a screening test for hermetically sealed hybrid microcircuits and multichip modules, needing them to withstand forces of up to 5,000 G for qualification.
Centrifuge work – It is the process of removing excess zinc from small hot dip galvanized parts by placing them in a perforated, rapidly spinning cylindrical container. Small parts which cannot be efficiently handled individually are centrifuged or spun to remove excess zinc and allow them to be processed in bulk in baskets. Nails, washers, bolts, and chains are typical centrifuge products.
Centrifuging bed motion – It occurs at critical and high speeds of rotation in a rotary kiln. This is an extreme condition in which all the bed material rotates with the drum wall.
Centripetal acceleration – It is the acceleration experienced by an object moving uniformly in a circular path, which is directed toward the centre of the circle and depends on the object’s speed and the radius of the circular path.
Centripetal force – It is the inward force needed to keep an object moving in a circular path, calculated as the product of mass and centripetal acceleration. This force acts radially inwards and is necessary for circular motion.
Centroid – It is the geometric centre point of a two-dimensional shape, line, or multi-dimensional object, representing the average position of all its points.
Centroidal axis – It is a straight line (axis) which passes directly through the geometric centre (centroid) of a 2D area or cross-section. It is used as a reference for calculating the moment of inertia in relation to parallel axes.
Centroid point – It is the geometric centre or average position of all points in a shape, figure, or data set. It is the exact point where a uniform object or cutout balances perfectly. It also refers to the overall mixture point in a simplex-centroid design, represented as (1/q, 1/q, …, 1/q), where ‘q’ indicates the number of components in the mixture. It serves as a central reference in analyzing the relationship among multiple variables in mixture experiments.
Ceracon (CERAmic CONsolidation) process – It is a granular ceramic medium which is used to transfer the pressure, instead of a gas, on HIP (hot isostatic pressing). The preform is prepared by cold compaction and then heated in a controlled atmosphere to the consolidation temperature. At the same time, the ceramic granules are also heated and charged into the die. The heated preform is inserted into the ceramic medium so that the preform is completely surrounded by the ceramic grains. The heated assembly is then transferred to a consolidation press, and an axial load is applied to the ceramic grain by moving the ram mechanically or hydraulically. The preform experiences axial and lateral forces, resulting in deformation and full densification with the correct processing variables. The consolidated part is ejected along with the granules from the die and separated from the ceramic granules. Preforms of alloy steels have been consolidated to full density by this process, and the surface finish of the product is influenced by the size and shape of the ceramic grains. The process is simple, and economic advantages include inexpensive tooling when low dimensional tolerances are adequate. Products such as low-alloy steel ratchet wrenches have been produced economically by this technique.
Ceramic – Ceramics are a class of inorganic, non-metallic products which are subject to a high temperature during manufacture or use. Typically, but not exclusively, a ceramic is a metallic oxide, boride, carbide, or a mixture or compound of such materials, i.e., ceramics include anions which play important roles in atomic structures and properties. A ceramic is any of the several hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as fireclay, at a high temperature. Refractories are ceramic materials.
Ceramic applications – These refer to the practical use of inorganic, non-metallic materials (such as oxides, carbides, and nitrides) to design components that withstand extreme heat, wear, and corrosion.
Ceramic ball – It is a spherical object made from ceramic materials, typically manufactured by blending and firing a ceramic powder mixture. These balls are known for their hardness, wear resistance, and chemical stability, making them suitable for various industrial applications, including catalyst support, filtration, and grinding.
Ceramic bond – It is the vitreous or crystalline material, formed on firing, between the coarser constituents of a ceramic body and giving cohesion and mechanical strength to the fired product.
Ceramic bonding – It refers to the process which holds together the atoms in ceramic materials, mainly through ionic and covalent bonds, giving them their characteristic strength and brittleness. This strong bonding contributes to ceramics’ high melting points and resistance to thermal and electrical conductivity, making them ideal for various applications such as in electronics and construction.
Ceramic capsule – It is a protective, hollow container made of advanced ceramic material used to enclose core substances, such as phase change materials (PCMs) for thermal energy storage or healing agents for self-healing concrete. It is built from inorganic, non-metallic engineering ceramics like alumina, zirconia, or silica, which provide high stiffness and chemical stability. It withstands extreme temperatures, corrosive fluids, and harsh thermal cycling without degrading or reacting with the enclosed material.
Ceramic coating application – It is the process of putting a liquid polymer, normally made of silicon di-oxide (SiO2), onto a surface so it chemically bonds and forms a thin, protective layer. Ceramic coating application needs five steps which are cleaning, roughening, under-coating, coating, and finishing.
Ceramic coatings – These coatings include glasses (with or without additions of refractory compounds), high-temperature coatings based on oxides, carbides, silicides, borides, or nitrides, cermets, and other inorganic materials. Ceramic coatings are applied to metals to protect them against oxidation and corrosion at room temperature and at high temperatures. Special coatings have been developed for specific uses, including wear resistance, chemical resistance, high reflectivity, electrical resistance, and prevention of hydrogen diffusion. Ceramic-coated metals are used for furnace components, heat treating equipment, chemical processing equipment, heat exchangers, rocket motor nozzles, exhaust manifolds, jet engine parts, and nuclear power plant components.
Ceramic component – It is a finished, high-performance part made from inorganic, non-metallic materials (such as oxides, nitrides, or carbides) which are shaped from powder and consolidated through high-temperature sintering. These advanced technical components are explicitly engineered for extreme industrial conditions.
Ceramic composite separator – It is an advanced porous engineering membrane which blends temperature-stable inorganic ceramic particles with a flexible polymer matrix to isolate battery electrodes while enabling ion transport.
Ceramic composition – It refers to an inorganic non-metallic material combination formed from metallic and non-metallic elements linked by strong ionic and covalent bonds.
Ceramic die – It is a specialized tooling or mould lined or constructed with advanced technical ceramics, such as zirconia or silicon nitride. It is used to shape, extrude, draw, or compress materials under extreme heat and pressure. It has high wear resistance, thermal stability, and chemical inertness. Ceramic dies consist of a type of tooling made from ceramic materials, typically used in processes like superplastic forming and metal extrusion. They are known for their high hardness, wear resistance, and ability to withstand high temperatures, making them suitable for applications where traditional steel dies can struggle.
Ceramic electrolyte – It is an inorganic, solid, non-metallic material which at conducts ions between the cathode and anode in electro-chemical devices like solid-state batteries and fuel cells.
Ceramic engineering – It is the specialized branch of engineering focused on the design, processing, and application of inorganic, non-metallic materials. It deals with substances which are neither organic nor metallic, such as oxides, carbides, nitrides, and silicates. It involves shaping and treating materials using intense heat, chemical synthesis, or precision sintering (bonding powders without full melting). It focuses on manipulating crystal structures and microscopic compositions to control macroscopic performance.
Ceramic fibre – It is man-made mineral fibre suitable for use as heat-insulating material, containing less than 2 % in total mass of alkaline oxide and alkaline earth oxides.
Ceramic fibre blanket – It is flexible, normally needled, ceramic fibrous insulating material, free of binder, with nominally determined dimensions.
Ceramic fibre board – It is a substantially rigid flat sheet normally containing inorganic and / or organic binder, produced by a wet process.
Ceramic fibre felt – It is a flexible, fibrous insulating material of nominally determined dimensions, containing some proportion of inorganic and / or organic binder.
Ceramic fibre mat – It is a flexible, non-needled, ceramic fibrous insulating material.
Ceramic fibre module – It is a ceramic fibre product formed into a unit used in furnace construction.
Ceramic fibre paper – It is a flexible, fibrous insulating material, formed on a paper making machine.
Ceramic fibre rope – It is a ceramic fibre which has been formed, with or without the addition of other filaments, wires or yarns, into one or several types of rope, i.e. twisted, cabled or lagging.
Ceramic fibre tape – It is a ceramic fibre which has been woven with or without the addition of other filaments, wires or yarns.
Ceramic fibre yarn – It is a ceramic fibre which has been twisted into a continuous thread with or without the addition of reinforcing filaments.
Ceramic filler – It is a solid, inorganic particle or fibre added to a base material, such as a polymer, plastic, or elastomer, to improve its mechanical, thermal, or electrical performance. It is made of inorganic ceramic compounds like alumina, silicon carbide, silica, or magnesium oxide. Ceramic fillers typically mix into the matrix physically without forming primary chemical bonds with the host polymer chains. They act as functional additives to improve material traits rather than just acting as cheap volume extenders.
Ceramic filter – It is a water purification device made from porous ceramic material with microscopic pores (typically around 0.2 micrometers to 0.5 micrometers). It acts like a fine physical sieve, trapping sediment, dirt, bacteria, and cysts while allowing clean water to pass through.
Ceramic gloss overcoat – It is a thin, non-metallic inorganic top layer, typically composed of silicon di-oxide (SiO2), titanium dioxide (TiO2), or alumina (Al2O3), applied over a metallic substrate to provide a high-reflectivity finish alongside extreme resistance to corrosion, oxidation, and thermal degradation.
Ceramic injection moulding – It is a manufacturing process used to produce complex, high-precision ceramic components in large volumes by injecting a heated blend of fine ceramic powder and a polymer binder into a mould.
Ceramic interconnectors – These are specialized high-temperature conductive oxide materials used in solid oxide fuel cells (SOFCs) to transfer electrons between individual cells while separating oxidizing and reducing gas atmospheres.
Ceramic interface i- It is the two-dimensional boundary zone separating two distinct phases or solid bodies, such as grain boundaries within a monolithic ceramic, or the contact layer between a fibre and a matrix in ceramic-matrix composites (CMCs).
Ceramic layer – It is a protective coating made of inorganic, non-metallic materials applied to a surface to resist extreme heat, wear, and chemical damage.
Ceramic liner – It is a protective internal layer made of advanced ceramic materials (such as alumina, silicon carbide, or zirconia) which shields industrial equipment from extreme wear, abrasion, corrosion, and high temperatures.
Ceramic matrix – It is the continuous primary phase in a ceramic matrix composite (CMC) which surrounds and holds embedded reinforcing materials like fibres, whiskers, or particles.
Ceramic-matrix composites – These are advanced composites which consist of fibres or whiskers in a ceramic matrix. Typical reinforcing materials include carbon fibres and silicon carbide fibres or whiskers. Matrix materials normally used are glass, glass-ceramics, alumina, and silicon nitride. Ceramic-matrix composites are resistant to both oxidation and wear.
Ceramic membrane reactor – It is a system that combines a chemical reaction and a selective material separation process into a single physical unit using an inorganic ceramic barrier. The ceramic component acts as both a chemical reactor housing a catalyst and a separation membrane. It removes products or adds reactants continuously, which shifts the chemical equilibrium and increases conversion yields.
Ceramic-metal coating – It is a mixture of one or more ceramic materials in combination with a metallic phase applied to a metallic substrate which van or cannot need heat treatment prior to service. This term can also be used for coatings applied to non-metallic substrates, for example, graphite.
Ceramic mould – It is a refractory structure made from ceramic powders, such as zircon [zirconium (IV) silicate, ZrSiO4], alumina, and silica, ceramic materials and binders which are fired at high temperatures (typically 870 deg C to 1,316 deg C) to create a strong, heat-resistant cavity used for precision metal casting. It handles extreme heat during precision metal casting for complex parts like turbine blades and dies.
Ceramic mould casting – Ceramic mould casting techniques are based on proprietary processes which use permanent patterns and fine-grain zircon [zirconium (IV) silicate, ZrSiO4] and calcined, high-alumina (Al2O3) mullite slurries for moulding. Except for distribution of grain size, the zircon slurries are comparable in composition to those used in ceramic shell investment moulding.
Ceramic moulding – It is a precision casting process which uses permanent patterns and fine-grain slurry for making moulds. Unlike monolithic investment moulds, which are similar in composition, ceramic moulds consist of a cope and a drag or, if the casting shape permits, a drag only.
Ceramic nano-particles – These are inorganic, non-metallic solid particles of a nano-scale size (typically under 100 nano-meters) which show unique mechanical, thermal, and electrical properties distinct from their macro-scale counterparts. These particles are formed from metallic and non-metallic compounds, such as metal oxides, carbides, nitrides, and borides, bound by strong ionic and covalent bonds.
Ceramic particles – These are the individual microscopic grains or powders of inorganic, non-metallic compounds, such as oxides, carbides, or nitrides, used as the foundational building blocks to fabricate advanced materials and composites. These particles are made of metallic and non-metallic elements linked by strong ionic or covalent bonds. These are hard, inorganic, non-metallic solid pieces (like oxides, carbides, or nitrides) mixed into a metal matrix to make strong composite materials.
Ceramic pattern – It refers either to a structured design or micro-feature configured on a ceramic surface to improve its functional properties, or to a physical model used to create refractory ceramic moulds in precision casting.
Ceramic perovskite material – It is a material which shares the same distinct crystal structure as calcium titanate (CaTiO3), defined by the general chemical formula ABX3. These ceramic structures are defined by specific atomic arrangements and ionic coordination.
Ceramic phase – It refers to a chemically and structurally uniform region within a ceramic material system, such as a specific crystal structure, a glassy / amorphous state, or a distinct liquid melt, which possesses uniform physical and chemical properties.
Ceramic phase diagram – It is a graphical map which shows which stable solid, liquid, or gas phases exist in an inorganic, non-metallic material under specific conditions of temperature, composition, and pressure.
Ceramic plate – It is a rigid, flat structural component made from high-purity inorganic, non-metallic materials like alumina or silicon carbide which are shaped and sintered for extreme industrial applications. It operates in extreme heat environments exceeding 1,600 deg C without melting or warping.
Ceramic powder – It is a collection of finely ground, inorganic, non-metallic particles used as the main raw material to manufacture solid, high-performance ceramic components. It is made of inorganic compounds combining metallic and non-metallic elements, such as oxides (alumina, zirconia), carbides (silicon carbide), or nitrides. It shows extreme hardness, high melting points, thermal stability, and corrosion resistance.
Ceramic process – It is the production of articles or coatings from essentially inorganic, non-metallic materials, the article or coating being made permanent and suitable for utilitarian and decorative purposes by the action of heat at temperatures sufficient to cause sintering, solid-state reactions, bonding, or conversion partially or wholly to the glassy state.
Ceramic product – It is an inorganic, non-metallic item made from ionic or covalent compounds (such as oxides, carbides, or nitrides) which are shaped and permanently hardened by high-temperature heat treatment or sintering. It resists intense wear, scratching, and compression. It features a very high melting point and acts as an effective refractory or thermal barrier. It withstands harsh chemical attacks and corrosion. It serves as a reliable electrical insulator, though specific compositions can be engineered as semiconductors or superconductors. It is prone to sudden fracture under stress or structural defects due to a lack of plastic deformation.
Ceramic pulley lagging – It is used for high-capacity conveyors or in slippery environments. It offers higher wear resistance and a higher friction factor.
Ceramic restoration – It refers to the process of repairing, reinforcing, or renewing degraded ceramic components to return them to their original structural integrity, dimensions, and performance specifications. It focuses strictly on reviving the mechanical properties, thermal resistance, and structural functionality of technical ceramics used in high-stress applications.
Ceramicrete – It is a matrix synthesized from the reaction of magnesium oxide (MgO) with mono-potassium phosphate (KH2PO4), used to treat nuclear wastes by forming magnesium potassium phosphate hydrate (MKP). It serves as a stabilizing and solidifying agent because of its ability to encapsulate contaminants effectively.
Ceramic saddle – It is a specially shaped random packing element made from high-strength ceramic material and used inside industrial towers to maximize contact between liquid and gas phases.
Ceramics and glasses – These are inorganic, non-metallic materials formed through high-temperature processing. Ceramics are crystalline materials featuring a regular, repeating 3D atomic arrangement. These are compounds of metallic and non-metallic elements, frequently oxides, carbides, or nitrides (e.g., alumina, zirconia). These have high hardness, extreme heat resistance, excellent electrical insulation / thermal insulation, but high brittleness. Glass is an amorphous (non-crystalline) solid with random atomic structure, formed by cooling a melt fast enough to avoid crystallization. Technically, glass is considered a supercooled liquid. Glasses are mainly based on silica (SiO2) mixed with fluxes and stabilizers like soda and lime. These have isotropic behaviour, transparency, smooth uniformity, and a gradual softening at the glass transition temperature rather than a sharp melting point.
Ceramic separator – It is a porous ceramic membrane or coating used to physically isolate the positive and negative electrodes while allowing ion transport. It provides exceptional thermal stability and puncture resistance, preventing short circuits even under extreme mechanical and thermal abuse.
Ceramic shot – It refers to highly durable, spherical blasting media, typically manufactured from zirconium di-oxide (zirconia), used in surface finishing and cold-working treatments. Driven by compressed air or centrifugal wheel turbines, millions of these micro-beads bombard a component’s surface to clean, finish, or mechanically strengthen the material. Unlike metallic steel shot, ceramic shot is chemically inert and highly fracture-resistant, which ensures that it does not leave contaminating iron deposits on treated parts.
Ceramic slurry – It is a pumpable, liquid-based suspension made of fine ceramic powders mixed with a liquid solvent (normally water), a binder, and dispersing agents.
Ceramic sphere – It is a precision-manufactured, inorganic, non-metallic round component or micro-structure made from advanced materials like alumina, zirconia, silicon nitride, or silica.
Ceramic structures – These structures refer to the atomic arrangements and internal microscopic organization of inorganic, non-metallic materials made of metallic and non-metallic elements (such as oxides, carbides, and nitrides) held together by strong ionic and covalent bonds.
Ceramic system – It refers to a specific combination of inorganic, non-metallic materials, chemical compositions, and phase equilibria studied or utilized to design high-performance structural, functional, or electronic components.
Ceramic tile – It is an inorganic, non-metallic slab made from natural clay, sand, and minerals which is shaped and fired at high temperatures to create a hard, durable surface. Ceramic tiles are classified by their porosity, structural density, and water absorption rates under standards like International Organization for Standardization standard ISO 13006.
Ceramic tools – These are cutting tools made from sintered, hot-pressed, or hot isostatically pressed alumina-base or silicon nitride-base ceramic materials.
Ceramic valve – It is a flow-control device or engine component which uses advanced technical ceramics, such as alumina, zirconia, or silicon nitride, for its internal parts to resist extreme wear and chemical corrosion.
Ceramic whiskers – These are thin, single-crystal fibres made of ceramic materials which are added to a matrix to improve fracture toughness and strength.
Ceramic welding – Ceramic welding is a method of repairing coke oven refractories. It is the welding of silica brick inside the coke oven. This is accomplished by conveying a powder mixture, rich in silica, through a small pipe lance via an oxygen enriched compressed air stream. The powdered silica mixture is jetted out of the end of the lance and ignites, almost explodes, against the hot wall of the coke oven. The heat of the reaction penetrates the silica brick creating a plastic zone of silica. The reaction also turns the powder silica mixture into a molten mass, which bonds to the aforementioned plastic zone on the silica brick. The appearance is similar to that of a welding joint. Also, the effects are similar, as new, equally strong material is deposited onto existing worn and cracked silica brick.
Cerargyrite – It is now officially known as chlorargyrite. It is a soft, heavy halide mineral composed of silver chloride (AgCl). It is also referred to as ‘horn silver’ because of its waxy, horn-like appearance. It serves as a highly valuable secondary ore of silver.
Cerate – It refers to a type of perovskite oxide (ABO3) which shows high protonic conductivity but has lower thermodynamic stability, making it prone to decomposition when exposed to steam and carbon di-oxide.
Cereal – It is the substance derived principally from corn flour, which is added to the core and moulding sands to improve their properties for casting production.
Ceria-based slurries – These are defined as polishing agents which utilize cerium oxide (CeO2) to achieve high removal rates for materials such as silicon di-oxides, glass, and silicon, using a distinct chemical reaction mechanism which disrupts bonds at the surface. These slurries are particularly effective in the optical industry because of their efficiency even with low particle content.
Ceria surface – It refers to the outer layer of ceria (CeO2) material, characterized by its stability and structure, which can be assessed through computational studies which evaluate surface energy and relaxations after cleaving from bulk material. Surface stability is typically ranked according to Miller indices, with the (111) surface showing the highest stability, followed by (110) and (100).
Cerium – It is a rare earth metal which in several respects resembles the alkali metals. The hot working properties of high alloy corrosion resistant and heat-resistant steels can be improved by the addition of cerium. Cerium in cast iron, acts as a deoxidizer and desulphurizer but when the sulphur content has been reduced to a value of around 0·015 %, cerium enters into solution in the cast iron and functions as a powerful carbide stabilizer. In quantities above 0·02 %, cerium is the operative factor in the production of nodular graphite structures in cast iron. Cerium is used in the improving the steel cleanliness, modifying the morphology of inclusions, and micro-alloying of steels. Cerium when added in small amounts to certain heat-resistant steels increases the resistance to oxidation and high temperature corrosion.
Cermet – Cermet is an acronym to designate ‘a heterogeneous combination of metal(s) or alloy(s) with one or more ceramic phases in which the latter constitutes approximately 15 % to 85 % by volume and in which there is relatively little solubility between metallic and ceramic phases at the preparation temperature’. It is a powder metallurgy product consisting of ceramic particles bonded with a metal.
Ceroxide – It is a surface or sub-surface casting defect caused by a chemical reaction between molten steel or iron and the moulding material (mould-metal reaction). It forms slag-like inclusions or crusts on the metal surface. Ceroxide is also called ceria. It is cerium di-oxide (CeO2) which is a high-performance rare-earth oxide famous for its unique oxygen storage and catalytic capabilities.
Certificate – It is an official document which serves as written proof or evidence which a certain fact, event, or qualification is true.
Certification – It is a formal process where an independent, authorized body gives official confirmation that a person, product, or organization meets specific standards or requirements.
Certification basis – It is the specific set of documented standards, requirements, and normative criteria used by an independent auditor to evaluate and confirm that an organization’s management system, product, or service complies.
Certification programme – It is a structured training initiative which typically includes classroom and online sessions, coaching, and reference materials aimed at improving skills and knowledge in a specific area, leading to a formal certificate upon completion.
Certified emission reductions – Certified emission reductions are a type of emissions unit (or carbon credits) issued by the clean development mechanism (CDM) executive board for emission reductions achieved by clean development mechanism projects and verified by a Department of Energy (DoE) under the rules of the Kyoto protocol. Certified emission reductions are either long-term (lCER) or temporary (tCER), depending on the likely duration of their benefit. Both types of certified emission reductions can be purchased from the primary market (purchased from original party which makes the reduction) or secondary market (resold from a market-place).
Certified laboratory – It is a facility which has received formal, independent recognition from an authoritative body confirming its technical competence and ability to produce accurate, reliable, and standardized test results.
Certified material – It is a substance, raw good, or sample backed by formal documentation which proves it meets defined chemical, physical, or regulatory standards.
Certified product – It is a product which has passed specific tests and quality checks to prove it meets recognized safety, performance, or environmental standards.
Certified reference material – It is a reference material (RM), accompanied by a certificate, one or more of whose property values are certified by a procedure which established traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence. Certified emission reductions reference materials are normally prepared in batches for which the property values are determined within stated uncertainty limits by measurements on samples representative of the entire batch. The certified properties of the Certified reference materials are sometimes conveniently and reliably realized when the material is incorporated into a specifically fabricated device, e.g., a substance of known triple-point into a triple-point cell, a glass of known optical density into a transmission filter, spheres of uniform particle size mounted on a microscope slide. Such devices can also be considered certified reference materials. All certified reference materials lie within the definition of ‘measurement standards’ given in the International Vocabulary of basic and general terms in metrology (VIM). Some reference materials and certified reference materials have properties which, because they cannot be correlated with an established chemical structure or for other reasons, cannot be determined by exactly defined physical and chemical measurement methods. Such materials include certain biological materials such as vaccines to which an international unit has been assigned by the World Health Organization.
Certifying agency – It is an authorized organization which evaluates and verifies whether a person, product, process, or organization meets specific standards, rules, or legal requirements.
Certifying authority – It is an independent body appointed by the purchaser to carry out a survey / inspection of the equipment and / or materials that they are buying. It is the responsibility of the supplier to provide the certifying authority with information, documents, access to works, and personnel to enable the survey to be carried out.
Certifying personnel – Certifying personnel are authorized individuals who hold the legal or official power to sign off, approve, and issue compliance certificates or maintenance releases.
Cetane number – It is an indicator of the ignition characteristics of fuel, reflecting its ability to auto-ignite quickly after injection. A higher cetane number (CN) value is associated with better ignition quality and shorter ignition delay, making it a crucial parameter in selecting methyl esters for bio-diesel.
C-frame press – It is also known as gap-frame press which is a general classification of press in which the uprights or housings are made in the form of a letter C, hence making three sides of the die space accessible.
Cf sample – It refers to the composite material which includes carbon fibres (Cf) in varying percentages (0.5 % to 2 %) within a tungsten-titanium carbide (W-TiC) matrix, characterized by properties such as grain size, relative density, Vickers micro-hardness, and tensile strength.
CG iron – It is the compacted graphite cast iron which is the cast iron having a graphite shape intermediate between the flake form typical of gray cast iron and the spherical form of fully spherulitic ductile cast iron.
C-glass – It is a glass with a soda-lime-boro-silicate composition which is used for its chemical stability in corrosive environments.
CGS system – It is centimeter-gram-second system. It is a metric system of units which uses the centimeter (cm), gram (g), and second (s) as its basic units for length, mass, and time, with a fourth unit which varies depending on whether it is based on the electro-static (esu) or electro-magnetic (emu) systems.
Chaboche’s multiple component plasticity model – It is an advanced constitutive material model in continuum mechanics and metallurgy used to describe the non-linear cyclic plastic behaviour of metals and alloys under complex loading. It is widely implemented in finite Element Method (FEM) software to predict structural fatigue life, deformation, and failure. The core feature of the ‘multiple component’ model is its superposition of multiple independent back-stress components. This enables a highly accurate representation of a metal’s transition from elastic to plastic deformation.
Chaetomorpha linum – It is a species of macroalgae which has been investigated for its potential in biodiesel extraction, showing that thermo-chemical liquefaction is more efficient for biofuel production compared to extraction with supercritical CO2 (carbon di-oxide).
Chafing – It is the repeated rubbing between two solid bodies which can result in surface damage and / or wear.
Chafing fatigue – It is the fatigue initiated in a surface damaged by rubbing against another body.
Chain – A chain is a series of connected links which are typically made of metal. A chain can consist of two or more links. Chains can be classified in several different ways. From a theoretical viewpoint, a chain is a continuous flexible rack engaging the teeth on a pair of gears. From a viewpoint based on its history and development, chain is a mechanical belt running over sprockets which can be used to transmit power or convey materials. Chains have the four basic functions namely (i) to transmit power, (ii) to convey objects or materials, (iii) to convert rotary motion to linear motion, or linear motion to rotary motion, and (iv) to synchronize or to time motion.
Chain and sprocket drive – The chain and sprocket arrangement operate similar to a bicycle. There is a large sprocket wrapping around the rotary drum with a chain on it which goes to the reducer and motor. The spinning motor turns a gear box, which spins a small sprocket which is attached by the chain to the large sprocket wrapping around the rotary drum. Chain and sprocket drive set ups are reserved for small rotary kilns, running up to 55 kilo-watts power. This type of arrangement is not suitable for larger kilns running above 55 kilo-watts power.
Chain alkanes – These are a category of alkanes where carbon atoms are joined together in a single continuous chain, characterized by the general formula CnH2n+2, where ‘n’ represents the number of carbon atoms.
Chain, carbon – A carbon chain is a skeleton of carbon atoms bonded together in a linear, branched, or cyclic sequence which forms the backbone of organic and polymer compounds.
Chain code – It is a lossless compression technique used to represent the boundary or contour of an object as a connected sequence of directional numbers. Instead of storing every absolute pixel coordinate (x, y) of an object’s edge, the method records a starting reference coordinate and a string of numbers indicating the direction of movement from one boundary pixel to the next.
Chain coding – It is a lossless compression and boundary representation technique used to encode an object’s contour as a connected sequence of directional numbers. Instead of storing the absolute x-y coordinate pair for every single pixel on an object’s boundary, the method records a starting reference coordinate and a string of numbers where each digit represents the relative direction of the next boundary step.
Chain conformation – It refers to the arrangement of polymer chains in specific structural configurations, such as helical or random coil forms, which influence their free energy states and properties during processes like crystallization.
Chain conveyors – The term chain conveyor means a group of different types of conveyors used in diverse applications, characterized by one or multiple strands of endless chains which travel entire conveyor path, driven by one or a set of sprockets at one end and supported by one or a set of sprockets on the other end. Materials to be conveyed are carried directly on the links of the chain or on specially designed elements attached to the chain. The load carrying chain is normally supported on the idle sprockets or the guide ways. The endless chains are kept tight by suitable chain tensioning device at the non-driven end.
Chain drive – It is a mechanism transmitting mechanical energy to wheels of conveyors, vehicles, and a wide variety of machines. It comprises a drive chain and sprockets. Chain drive is a way of transmitting mechanical power from one place to another.
Chain driven belt conveyor – It is a special type of conveyor in which the specially designed belt is driven by a moving chain, where belt only serves as load carrier, and motion is by a chain conveyor.
Chain-drop hammer – It is a traditional mechanical forging machine which raises a heavy upper ram using a linked chain mechanism and drops it under gravity to plastically deform heated metal.
Chain end – It refers to the terminal end of a polymer molecule or network strand where it is no longer chemically linked or cross-linked to the rest of the matrix.
Chain extender – It is a low-molecular-weight chemical reagent used to connect shorter polymer chains into longer ones, hence increasing the overall molecular weight of the material.
Chain extension – It is a chemical process which increases the molecular weight of prepolymers or degraded polymers by reacting their end groups with low-molecular-weight reagents called chain extenders.
Chain-folded model – It is a model for crystalline polymers which describes the structure of platelet crystallites. Molecular alignment is accomplished by chain folding which occurs at the crystallite faces.
Chain-growth polymerization – It is a process where monomer units add one at a time to a single active site on a growing polymer chain.
Chain guard – It is a protective covering for drive or conveyor chains, implemented for safety reasons.
Chain hoist – It is used to manually lift very heavy objects. It is operated by pulling upon the slack section of a continuous chain which wraps around two pulleys on a common shaft. The two pulleys are joined together such that they rotate as a unit on the single shaft that they share. The relative sizing of the two connected pulleys determines the maximum weight which can be lifted by hand. If the pulley radii are close enough, then the load remains in place (and not lower under the force of gravity) until the chain is pulled.
Chain intermittent weld – It is an intermittent weld on both sides of a joint in which the weld increments on one side are approximately opposite those on the other side.
Chain jack – It is a device which moves linearly in a reciprocating motion to pull in, tension, or lift heavy loads using a continuous chain. It is typically powered by hydraulic cylinders or electric motors which drive internal clamping mechanisms.
Chain length – It is the length of the stretched linear macro-molecule, very frequently expressed by the number of identical links.
Chain mail – It is a geometrically interlocked, flexible assembly of metal rings or modular units which can shift between compliant (fluid-like) and rigid (jammed) states under applied forces.
Chain mechanism – It is an assembly of rigid bodies or links connected by joints (or a physical loop of connected links like a roller chain) designed to transfer motion, force, or power between machine elements. The term refers to two main concepts namely a power transmission chain system (like a bicycle chain) or a kinematic chain mechanism (the theoretical framework of inter-connected links).
Chain of bundle model – It is an advanced architectural framework used to model complex, hierarchical systems by nesting modular components (bundles) sequentially (chains). Instead of treating a system as one massive equation or a flat list of variables, chain of bundle (CoB) breaks the system down into self-contained ‘bundles’ of physics, data, or logic, and links them together so the output of one bundle directly feeds and dictates the behaviour of the next.
Chain polyols – These are low molecular weight diols or poly-functional alcohols which act as chain extenders or soft segments in polyurethane (PUR) production’
Chain reaction – It is a reaction which initiates its own repetition. In a fission chain reaction, for example, neutrons released in fission produce an additional fission in at least one further nucleus. These, in turn, can be absorbed by other fissionable nuclei, releasing still more neutrons. Where the number of neutrons released in a given time equals or exceeds the number of neutrons lost by absorption the fission chain reaction is self-sustaining.
Chain roller conveyor – It is a conveyor featuring tread rollers with attached sprockets, driven by a chain.
Chain rule – It is a formula used to find the derivative of a composite function, meaning a function nested inside another function. It is a mathematical principle which describes how to differentiate a function of a variable which is itself a function of one or more other variables, allowing for the calculation of partial derivatives in multi-variable calculus.
Chain scission – It is the irreversible breaking of covalent chemical bonds along the main backbone of a polymer chain.
Chain segment – It refers to a specific portion of a polymer macro-molecule (polymer segment) or a discrete link /section of a mechanical or anchor chain. It is an imaginary or physical section within a long polymer molecule chain which consists of multiple repeating monomer units
Chain slings – These slings are made from steel chains. Chains are normally used because of their strength and ability to adapt to the shape of the load. However, care is required to be taken, while using alloy steel chain slings since these slings are subject to damage by sudden shocks. Misuse of steel chain slings can damage the sling, resulting in sling failure and possible accident.
Chain solution – It typically refers to a structured, sequential approach or a scalable framework, such as an on-chain / off-chain network architecture or a synchronized process chain, used to optimize throughput, manage operations, or transmit mechanical force.
Chain structure – It refers to the arrangement of blockchain designs, which can include single-chain, multi-chain, side-chain, and cross-chain configurations. These structures influence the processing power, scalability, and privacy of transactions within the block-chain system.
Chain transfer – It is a conveyor mechanism used to redirect unit loads across intersecting lines by shifting items perpendicular to their original direction of travel. It typically consists of multiple strands of chain which lift or emerge between the rollers of a roller conveyor to move pallets, totes, or heavy cartons onto an adjacent conveyor line. It is also a chemical reaction during chain polymerization where the active centre of a growing polymer chain is transferred to another molecule or another site on the same molecule. This action stops the growth of the original polymer chain (making it a ‘dead’ polymer) while simultaneously creating a new active radical or species which can start the growth of a new chain.
Chain transfer agent – It is a chemical substance added during polymerization to stop the growth of one active polymer chain and start a new one.
Chain transfer reaction – It is a polymerization process where the active growth centre (such as a radical) of a growing polymer chain is transferred to another molecule, stopping the original chain’s growth while starting a new one.
Chain-wheel – It is a chain operated wheel attached to a manual actuator with a closed loop of chain to enable the operation of an overhead valve.
Chain-wheel operated valve – It is an overhead valve operated by a chain drive wheel instead of a hand-wheel.
Chain work – Large or complex steel fabrications which need to be handled individually are suspended on chains for galvanizing. These products include large pipes, box and boat trailers, and heavy items.
Chalcocite – It is a sulphide ore of copper with the chemical formula Cu2S. It is a highly valued ore since it approaches 80 % copper by weight.
Chalcogens – These are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements namely oxygen, sulphur, selenium, tellurium, and the radioactive elements polonium and livermorium.
Chalcopyrite – It is an important ore of copper. It is a copper iron sulphite with the chemical formula CuFeS2. It is the most common mixed copper-iron sulphide ore and main commercial source of copper.
Chalcocite – It is a rich copper sulphide mineral with high copper content and chemical formula Cu2S..
Challenging separation – It refers to the process of dividing a complex mixture of substances which are chemically or physically very similar, making them exceptionally difficult to isolate using standard methods. These separations normally need advanced, energy-intensive, or highly specialized technologies since the components share nearly identical boiling points, molecular sizes, solubilities, or chemical behaviours.
Chalking – It is the development of loose removable powder at the surface of an organic coating normally caused by weathering.
Chalk test – It refers to a few distinct visual and physical inspection methods. It very frequently describes a seal-contact check, a weld leak test, or a paint degradation test for surface coatings. In foundries, it is a method of crack detection which consists of applying a penetrating liquid to the part, removing the excess from the surface which is then coated with whiting or chalk. After a short time, the penetrant seeps out of the cracks into the whiting, causing an appreciable difference in whiteness.
Chamber, combustion – Combustion chamber is a closed, heat-resistant space where fuel and an oxidizer mix and burn to turn chemical energy into thermal and pressure energy.
Chamber design – It is the process of planning and shaping an enclosed space, very frequently an engine’s combustion area, a thermal or vacuum vessel, or a structural profile, to control fluid flow, pressure, heat transfer, and chemical reactions safely and efficiently.
Chamber gas – It very frequently refers to a specialized gas-filled ionization chamber used to detect and measure ionizing radiation, or it relates to specialized mechanisms like chamber gas lift systems.
Chamber gas lift – It is an artificial lift technique used to extract fluids (like oil) from low-pressure wells.
Chamber, ionization – Ionization chamber is a sealed metal enclosure filled with a specific gas which contains electrodes.
Chamber method – It normally refers to using an enclosed, controlled space, such as an environmental test chamber or an open flux chamber, to isolate, regulate, and measure specific physical, chemical, or thermodynamic processes.
Chamber pressure – It is the force per unit area exerted by a gas, fluid, or earth material against the inner walls of a confined enclosure or structural cavity.
Chamber, process – Process chamber is defined as an enclosed environment in an SLM (selective laser melting) machine which is purged with an inert gas to maintain an oxygen level below 0.2 %, important for preventing oxidation of materials during processing. The chamber’s conditions influence the quality of the fabricated parts by controlling factors such as gas flow rate and spatter removal.
Chamber shape – It refers to the specific geometric configuration of an engine’s combustion space, formed by the cylinder head and the piston crown, which dictates how air and fuel mix, burn, and produce power.
Chamber wall – It is a structural boundary or partition which encloses a specialized enclosed space (a chamber), designed to contain fluids, withstand pressure or thermal gradients, and isolate internal physical or chemical processes from the external environment.
Chamfer – It is a beveled surface to eliminate an otherwise sharp corner. It is also a relieved angular cutting edge at a tooth corner.
Chamfer angle – It is the angle between a reference surface and the bevel. On a milling contour, it is the angle between a beveled surface and the axis of the cutter.
Chamfering – It is the making of a sloping surface on the edge of a member. It is also called beveling.
Chamfer matching – It is a fast digital image processing and computer vision technique used to find the best alignment between a template shape and an edge map of a target image.
Chamotte – It is a raw material normally made from crushed and ground potsherds, reintroduced into crude clay to temper it before making ceramic ware. It has a high percentage of silica and alumina. It is normally available as a powder or chippings.
Change control – Change control is the process of identifying, evaluating, approving, and implementing changes. It ensures that changes are introduced in a controlled and effective manner and that any adjustments necessitated by changes are also addressed.
Change model – It is a repeatable, step-by-step framework which guides an organization or individual from a current state to a stabilized new state.
Change in entropy – It measures the transfer of heat relative to absolute temperature as a system moves from one state to another.
Change of basis – It is the process of rewriting a vector, tensor, or system equation from one coordinate system or reference frame into another without changing the underlying physical object.
Change of density – It is the variation in a material’s mass per unit volume caused by shifts in temperature or pressure.
Change of dimension – It refers to a physical alteration in the size, volume, or geometry of a component. Change of dimension in materials normally takes place because of thermal expansion, moisture absorption (cause of swelling), rusting, and stress and aging.
Change package – It is a comprehensive collection of documents which outlines all technical modifications to a design, including redlined design documents, rework instructions, and a completed change form detailing justifications, impacts, and affected applications. It ensures that all necessary information is available for implementing changes in engineering projects.
Channel – It is a U-shaped or C-shaped metal beam (such as steel or aluminum) used for framing, load-bearing, and structural support. Channel is also a natural or man-made conduit or waterway where liquid flows with a free surface exposed to atmospheric pressure. It is also a communication path between a signal transmitter and a signal receiver, or, a pre-selected operating frequency for a radio system.
Channel allocation – It is the process of dividing and assigning available communication resources, such as frequency bands, time slots, or bandwidth, to different users, devices, or cells in a network. The main goal is to maximize data transfer efficiency and spectral capacity while preventing signal collisions and interference.
Channel allocation algorithm – It is a method used to assign communication channels, frequency bands, or time slots to nodes, base stations, or users in a network. The main goal is to maximize data throughput and spectral efficiency while keeping interference and call blocking low.
Channel bandwidth – It is the range of frequencies available for transmitting data over a communication channel, which can be effectively utilized through technologies such as wavelength division multiplexing (WDM) to achieve high data rates, particularly in optical systems.
Channel basis – It means that operations, allocations, or filtering are managed per individual communication channel rather than treating the entire transmission spectrum as a single block.
Channel bit – It is a single binary digit (0 or 1) which is actually modulated, encoded, and physically transmitted across a communication medium.
Channel capacity – It is the maximum rate at which information can be transmitted over a communication channel, measured in bits per symbol, considering the effects of noise and power constraints. In the case of an additive white Gaussian noise (AWGN) channel, it is expressed by Shannon’s noisy channel capacity theorem, indicating that this rate can be achieved with a bit error rate approaching zero as channel coding is extended over longer sequences.
Channel code – It is a set of rules to add structured redundancy (extra check or parity bits) to a data stream, enabling the receiver to detect and correct errors caused by noise, interference, or fading during transmission.
Channel coder – It is a device or algorithm at the transmitter which adds controlled extra bits, called redundancy, to a digital data stream so the receiver can detect and fix errors caused by noisy or weak signals.
Channel coding – It is a technique used to protect transmitted data from noise, interference, and signal fading by adding controlled redundant (extra) bits before transmission.
Channel coding theorem – It is a principle which establishes the capacity of any discrete memoryless channel, stating that this capacity is the supremum of the mutual information between the input and output, maximized over all possible input distributions. It also indicates that even noisy channels can have a positive capacity.
Channel coherence time – It is the statistical time duration over which a wireless communication channel’s impulse response remains relatively invariant and predictable. It measures how long the channel’s properties (like amplitude and phase) stay correlated before changing considerably.
Channel component – It is a specific pathway, medium, or structural element within a system which transmits signals, data, fluid, or power between a source and a destination.
Channel condition – It refers to the current state and quality of a communication link between a transmitter and a receiver.
Channel conductance – It is the measure of the ease with which ions or electric current can flow through a specific channel in a semiconductor device.
Channel connected component – It refers to sub-circuit blocks whose inputs and outputs connect exclusively to transistor gates or main I/Os (inputs / outputs).
Channel correlation – It is a measure of how similarly signals behave across different paths or antennas in a wireless communication system. In multiple-input multiple-output (MIMO) systems, channel correlation describes the statistical dependence between fading signals traveling through distinct spatial, transmit, or receive paths. When antennas are placed too close together or when obstacles limit the scattering of radio waves, the signals experience similar environmental effects, making them correlated.
Channel correlation matrix – It is a mathematical representation which describes the spatial richness and signal dependencies between different antenna pairs in a multiple-input multiple-output (MIMO) wireless communication system.
Channel count – It is the total number of distinct input, output, or active pathways available in a system, device, or data file.
Channel crosstalk – It is an unwanted transfer of signals or interference from one transmission channel or circuit into a neighboring channel.
Channel data rate – It is the speed at which data is transmitted through a communication channel, measured in bits per second (bps).
Channel decoder – It is a hardware or software component in a communication system which uses added data redundancy to detect, locate, and fix errors caused by noise or interference during signal transmission.
Channel depth – It is also called flow depth. It is the vertical distance from the bottom of an open channel (like a river, canal, or drainage ditch) up to the free surface of the water. Channel depth is sensitive to slope.
Channel device – It typically refers to the physical semi-conductor pathway in a transistor, like a metal–oxide–semiconductor field-effect transistor (MOSFET) which controls current flow, or a logical communication pathway used by software / servers to connect with hardware devices.
Channel diameter – It refers to the diameter of a circular channel used in fluid flow calculations, as applied in the classic Darcy Weisbach equation. In non-circular channels, the hydraulic diameter is utilized instead for pressure drop calculations.
Channel die – it is a specific type of multi-piece tooling assembly. It consists of a central channel (U-shaped block), two split dies, and a clamping plate.
Channel dimensions – These dimensions refer to the physical measurements and geometric parameters which define a structural or fluid-carrying channel, such as its depth, width, length, and cross-sectional profile.
Channel dispersion – It is a phenomenon where a transmitted signal spreads out in time, frequency, or space as it propagates through a communication medium, leading to signal distortion and inter-symbol interference.
Channel distortion – It is the unwanted alteration of a transmitted signal’s shape, timing, amplitude, or phase as it passes through a communication channel or medium.
Channel equalization – It is a signal processing technique used to estimate and reverse the distortions, such as amplitude loss, phase shifts, and inter-symbol interference, which a signal incurs while passing through a physical communication channel.
Channel estimation – It is the process used in communication engineering to figure out how a physical medium (like air or a wire) changes a transmitted signal’s amplitude, phase, and delay.
Channel estimation error – It is the mathematical difference between the true characteristics of a communication channel (such as signal fading, delay, or phase shift) and the estimated values calculated by a receiver.
Channel flow – It is a type of wall-bounded turbulent flow which occurs within a confined space, typically characterized by substantial turbulence production mechanisms located in the buffer layer near the walls. It is the gravity-driven movement of a liquid (normally water) through a conduit or channel which has a free surface exposed to atmospheric pressure.
Channel forming die – It is a press tool used to bend flat sheet metal into a structural ‘C’ or ‘U’ shape (known as a channel section).
Channel frequency selectivity – It is the phenomenon where different frequencies of a transmitted signal experience varying levels of attenuation and distortion because of the multipath propagation, affecting the performance of wireless communication systems.
Channel gain – It is a scalar or complex factor which measures how much a transmitted signal’s amplitude or power is altered (scaled or attenuated) as it travels through a communication channel from a transmitter to a receiver.
Channel geometry – It refers to the physical dimensions and cross-sectional shape of a flow conduit, such as a river, artificial canal, or structural beam, which dictate how fluids move or how structural loads are supported. It specifically defines the size and form of open channels exposed to the atmosphere.
Channel hot electron injection – It refers to the process in MOSFET (metal–oxide–semi-conductor field-effect transistor) devices where energetic electrons are injected from the channel into the SiO2 (silica) traps when the gate voltage is comparable to the drain voltage, leading to an increase in gate current as the inversion charge in the channel rises. This mechanism can also involve the injection of secondary hot electrons generated from impact-ionization avalanche, contributing to degradation at the Si-SiO2 (silicon-silica) interface.
Channel impairment – It is a physical factor, noise, or limitation in a communication medium which alters a signal as it travels from a transmitter to a receiver, causing data errors or signal degradation. Since the received signal is never an exact match of the transmitted signal, systems are to be designed with error-correction, and filtering to combat these imperfections.
Channel impulse response – It is the output of a communication channel when it receives a brief, sharp input signal called an impulse. It characterizes how a medium (like a wireless radio link, fibre optic cable, or copper wire) alters, delays, and distorts a signal during transmission.
Channel induction furnace – It consists of a refractory lined steel shell which contains the molten metal. Attached to the steel shell and connected by a throat is an induction unit which forms the melting component of the furnace. The induction unit consists of an iron core in the form of a ring around which a primary induction coil is wound. This assembly forms a simple transformer in which the molten metal loops comprise the secondary component. The heat generated within the loop causes the metal to circulate into the main well of the furnace. The circulation of the molten metal causes a useful stirring action in the melt. The channel IF is normally used for melting low melting point alloys, or as a holding and superheating unit for higher melting point alloys such as cast iron.
Channel input – It refers to the specific physical or logical pathway through which a signal, data, or power enters a communication system, data acquisition device, or control hardware.
Channel interference – It is the disruption or degradation of a communication signal caused by unwanted energy or overlapping transmissions from other sources within the same frequency spectrum.
Channel knowledge – It refers to the quantified information or data collected about the physical characteristics of a communication medium (the channel) between a transmitter and a receiver.
Channel knowledge engineering – It refers to the systematic process of modelling, predicting, and adapting to the behaviour of a wireless communication channel using advanced computational techniques like machine learning and artificial intelligence. Instead of relying purely on traditional, real-time mathematical estimations, channel knowledge engineering (CKE) builds an intelligent ‘knowledge base’ of the physical environment to optimize signal transmission.
Channel layer – It refers to a communication abstraction layer (such as in software or networking) or a boundary layer phenomenon in fluid mechanics. A communication or network abstraction layer handles message transmission, routing, and serialization between different program instances or network end-points.
Channel length modulation – It is the phenomenon where the effective channel length of a MOSFET (metal–oxide–semi-conductor field-effect transistor) reduces as the drain bias increases, resulting in an increase in drain current even in saturation. This effect is influenced by the shift of the saturation point towards the source with higher drain voltage.
Channelling – It refers to the preferential or unobstructed movement of particles, fluids, or ions through specific open pathways or lattice structures, frequently bypassing denser regions or intended constraints. This phenomenon happens when the ascending gases in the furnace does not properly get uniformly distributed both radially and circumferentially in the furnace and find a passage of least resistance.
Channelling pattern – It is a pattern of lines observed in a scanning electron image of a single-crystal surface caused by preferential penetration, or channeling, of the incident beam between rows of atoms at certain orientations. The pattern provides information on the structure and orientation of the crystal.
Channelization – It consists of straightening and deepening streams so that water can move faster. It is a marsh-drainage tactic which can interfere with waste assimilation capacity, disturb fish and wildlife habitats, and aggravate flooding.
Channelization codes – These are user-specific codes generated recursively in a binary tree structure to separate transmissions from a single source in a WCDMA (wideband code division multiple access) system, allowing for the maintenance of orthogonality between codes while enabling changes in spreading.
Channel matrix – It is a mathematical array of coefficients which describes how a signal changes as it travels from multiple transmitters to multiple receivers through a physical medium.
Channel model – It is a mathematical representation of how a communication medium alters, attenuates, or degrades a signal as it travels from a transmitter to a receiver.
Channel modelling – It is the process of creating mathematical or algorithmic representations of a communication medium to predict how signals behave as they travel from a transmitter to a receiver.
Channel output – It refers to the resulting signal, data, or information received at the destination end of a communication, hardware, or control pathway after transmission and potential alteration by noise or system dynamics.
Channel parameter – It is a specific physical or digital characteristic which describes how a communication pathway behaves, transmits data, or handles signals.
Channel power – It is the total signal power contained within a specified frequency channel bandwidth. It measures the sum of all power falling inside the defined integration bandwidth of a channel.
Channel processing – It refers to the manipulation, estimation, and correction of signals passing through a communication medium to remove distortion, reduce noise, and ensure reliable data transmission.
Channel quality – It is a measure of how well a communication path handles data under current noise, fading, and interference conditions. It estimates the highest data rate or modulation and coding scheme (MCS) a signal can sustain with an acceptable error rate (typically under 10 %).
Channel quality Indicator – It is a feedback parameter sent from a user device (like a phone) to a cellular base station to report the quality of the wireless downlink channel.
Channel realizations – These refer to specific examples of a communication channel’s behaviour or characteristics, which can influence the achievable rate and outage probability in a relay channel context. These realizations help determine the optimal performance strategies, such as the conditions under which relaying outperforms direct transmission.
Channel reciprocity – It is the physical property where a wireless propagation channel’s characteristic, such as gain, phase, and delay, remain identical in both forward (downlink) and reverse (uplink) transmission directions.
Channel resistance – It refers to the electrical resistance of the conductive path (the ‘channel’) in a field-effect transistor (like a metal–oxide–semiconductor field-effect transistor) or thin-film transistor (TFT), or alternatively, the fluid flow resistance in a microfluidic or physical channel.
Channel response – It is the characterization of a communication channel’s output in response to an input signal, represented either in the frequency domain or the delay domain as a function of frequency or delay, respectively. It describes how different frequencies are transmitted and can be influenced by factors such as bandwidth and filtering characteristics.
Channels – Channels are C-shaped hot-rolled carbon steel sections featuring a vertical web and rounded corners on the top and bottom flanges. They include a wide web and two flanges, which can be either parallel or tapered.
Channel section – It is the cross-section taken perpendicular to the main direction of flow in an open conduit or water body (such as a river, canal, or flume) where the fluid surface is exposed to the atmosphere. Channel section is also a hot-rolled or cold-formed structural steel profile shaped like a ‘C’ or ‘U’.
Channel size – It refers to the physical dimensions or cross-sectional measurements of a structural profile, fluid flow path, or electronic routing pathway.
Channel state – It describes the current propagation properties and physical condition of a communication link between a transmitter and a receiver.
Channel state information – It is a set of physical-layer properties which describes how a wireless signal propagates from a transmitter to a receiver. It represents combined channel effects like fading, scattering, power decay, and multipath behaviour.
Channel state information reference signal – It is a specialized downlink physical signal used in LTE (long term evolution) and 5G NR (new radio) networks to let user devices measure radio channel quality and conditions.
Channel structure – It refers to a type of arrangement in zeolites characterized by interconnected channels formed by rings, such as 5-rings, which create major pathways for molecular movement. Examples include mordenite with 12- and 8-ring channels, and synthetic zeolites which feature intersecting channels with specific geometries. It is also an open channel structure which is a man-made or natural conduit (like a canal, spillway, or river) where liquid flows with a free upper surface exposed to the atmosphere. Channel structure is also a type of hot-rolled or cold-formed steel beam whose = cross-section forms a ‘C’ or ‘U’ shape, featuring a wide vertical main section (the web) and two horizontal projections at the top and bottom (the flanges) facing only one side. Channel structure also means micro-channels or flow-field channels (such as those in fuel cells or heat exchangers) carved into bipolar plates or blocks.
Channel tap – It is a discrete point or coefficient in a tapped delay line model which represents a specific signal path, time delay, and attenuation level in a multi-path transmission channel.
Channel transfer function – It is a representation of the frequency response of a communication channel, estimated at pilot subcarriers using methods such as the least-square (LS) estimator, with values at other subcarriers obtained through filtering.
Channel transistor – It is the physical path or region of semi-conductor material through which electric current flows between the source and drain terminals.
Channel, transmission – Transmission channel is the physical or logical pathway that carries a signal or data from a transmitter to a receiver. It is a system which can be characterized by its set of input and output signals, along with the conditional probabilities of receiving specific output signals given particular input signals. A discrete memoryless channel is a specific type where the output at any moment depends only on the corresponding input at that moment, without influence from previous inputs.
Channel variation – It typically refers to fluctuations in signal quality within communication systems, or physical and geometric changes in fluid / open-channel flow.
Channel wave-guide – It is also called a strip wave-guide. It is an optical or micro-wave structure which confines and guides waves in two transverse dimensions along a specific path on or beneath the surface of a solid, transparent material.
Chaotic fluctuations – These fluctuations refer to unpredictable, complex, and aperiodic variations in a dynamical system’s behaviour which arise from underlying deterministic non-linear laws.
Chaotic signal – It is a bounded, aperiodic, and deterministic wave-form generated by a non-linear dynamical system that appears random but is completely reproducible under identical starting conditions. The signal follows precise mathematical rules and equations, unlike true random noise.
Chaplet – It is the metal support which holds a core in place within a casting mould. Molten metal solidifies around a chaplet and fuses it into the finished casting.
Chapman-Kolmogorov equation – It is a fundamental mathematical identity used to calculate the multi-step transition probability of a Markov process by summing or integrating over all possible intermediate states.
Char – It is the solid, carbon-rich residue which remains after carbonaceous materials (like coal or organic biomass) undergo thermal decomposition or pyrolysis (heating without oxygen) to drive off volatile gases and tars.
Characteristic, circuit – Circuit characteristics refer to the properties of an electrical circuit which influence its performance, including sensitivity to temperature variations, dynamic range, power consumption, and latency of the circuit operation. These characteristics can differ considerably between analog and digital circuits.
Characteristic compressive strength – It is a statistical parameter which defines the strength of a material (such as concrete), meaning that only a small, defined proportion of test samples, typically 5 %, is allowed to fall below this value.
Characteristic cube strength – It is the compressive strength of concrete below which not more than 5 % of test results are expected to fall.
Characteristic curve – It is a graph which plots the relationship between two or more variable properties of a system, device, or material to show its performance, behaviour, or operational limits.
Characteristic data – It refers to the specific attributes, features, or qualitative and quantitative properties which define and describe a data subject or data-set.
Characteristics data file format – It defines the specific structural rules, encoding methods, and organization schemes used to store attributes, properties, and values in a computer file.
Characteristic directions – These are specific spatial or coordinate orientations along which partial differential equations (PDEs), especially hyperbolic systems governing fluid dynamics, wave propagation, or continuum mechanics, degenerate into ordinary differential equations.
Characteristic electron energy loss phenomena – It consists of the inelastic scattering of electrons in solids that produces a discrete energy loss determined by the characteristics of the material. The most probable form is because of the excitation of valence electrons.
Characteristic equation – It is a polynomial equation derived from a system’s governing matrix, differential equation, or control transfer function, and it is solved to analyze system stability, natural frequencies, and dynamic behaviour.
Characteristic frequency – It is a unique, inherent rate of oscillation at which a physical system or material naturally tends to vibrate or respond based on its core properties like mass and stiffness.
Characteristic function –It is the expected value of an imaginary exponential of a random variable. It is a continuous, positive-definite function which uniquely represents the distribution of a random variable. It is also characterized by the property that the characteristic function of the sum of independent random variables equals the product of their individual characteristic functions.
Characteristic impedance – It is the ratio of the voltage wave amplitude to the current wave amplitude as a signal travel in a single direction along a transmission line without any reflections.
Characteristic polynomial of a linear operator – It is the polynomial got from the matrix representation of the operator, which has the same roots as the eigenvalues of the operator. It remains invariant under changes of the basis in a finite dimensional vector space.
Characteristic polynomial of a square matrix – It is a special polynomial whose roots are the eigenvalues of that matrix.
Characteristic, product – Product characteristics are the specific, measurable physical, chemical, or functional attributes of a part, component, or assembly that define its design and need verification.
Characteristic radiation – It consists of electro-magnetic radiation of a particular set of wave-lengths, produced by and characteristic of a particular element whenever its excitation potential is exceeded. Electro-magnetic radiation is emitted as a result of electron transitions between the different energy levels (electron shells) of atoms. The spectrum consists of lines whose wave-lengths depend only on the element concerned and the energy levels involved.
Characteristics – In case of materials, characteristics are the physical, chemical, or mechanical properties. These properties determine how a material functions and be manufactured. In case of hazardous waste, characteristics fall into four categories namely ignitability, corrosivity, reactivity, and toxicity.
Characteristic values – These values refer to a value of a material property derived from the statistical evaluation of test data, typically expressed as a specified variation from the mean with a given confidence level. They indicate the probability that a test value exceeds this characteristic value, normally represented in terms of percentiles and standard deviations.
Characteristic velocity – It is a measure of the energy available from the combustion process, independent of nozzle characteristics. It is often used to assess combustion efficiency and can be determined from both measured test data and calculated thermochemical parameters. It is also a key parameter in fluid dynamics, which helps to characterize the flow and is used to calculate the Peclet number, influencing the mixing of passive scalars in a flow.
Characteristic X-ray radiation – It is a unique set of X-ray frequencies emitted by a metal atom when high-energy particles knock out an inner-shell electron, and an outer-shell electron drops down to fill the empty space.
Characterization – It involves analyzing and understanding the properties of materials at scales both visible and invisible to the naked eye. Characterization techniques are used to get information about the chemical, physical, mechanical, and electrical properties of materials, which are critical for understanding their behaviour and developing new materials with specific properties. It is also the process of classifying nuclear material.
Characterization of nano-materials – It refers to the processes used to get high-resolution information about the physical and chemical properties of nano-materials at the single entity level, which is necessary for understanding their functionality related to size, shape, and structure.
Characterized ball or gate – It is a ball or gate the shape of whose port has been altered to provide a specific throttling capability. One of the most common is the V-port ball design.
Character recognition – It is a pattern recognition technique which involves the identification of characters in different formats, normally applied in document processing and related fields.
Char briquetting – It is a mechanical compaction process which transforms loose, low-density carbonized material (char or charcoal dust) into highly densified, uniformly shaped solid fuel blocks called briquettes. Since pure char lacks natural plasticity and cannot bind on its own, the process needs combining the char fines with a binding agent and compressing the mixture under pressure.
Char burnout – It is the final, slowest stage of solid fuel combustion where residual carbon (char) reacts with gases like oxygen, carbon dioxide, or water to completely convert into gaseous products.
Charcoal – It is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, frequently by forming a charcoal kiln, the heat is supplied by burning part of the starting material itself, with a limited supply of oxygen. The material can also be heated in a closed retort.
Charcoal pig iron – It is the pig iron produced in a blast furnace, using charcoal as the fuel.
Char combustion – It is the slow, heterogeneous (gas-solid) oxidation of the solid carbonaceous residue left after a fuel undergoes devolatilization.
Char formation – It is the thermal conversion of carbonaceous materials into a solid, carbon-rich residue called char through pyrolysis, incomplete combustion, or carbonization. It is the solid-phase residue left behind after volatile gases, moisture, and tars are driven off from organic matrices under high heat.
Char gasification – It is the thermo-chemical process where solid carbonaceous residue (char) reacts with gasifying agents like steam, carbon di-oxide, or oxygen at high temperatures to produce a combustible gas mixture known as synthesis gas (syngas).
Charge – It is the materials fed into a furnace. It is the weights of different liquid and solid materials put into a furnace during one feeding cycle.
Charge acceptance – It is the willingness of a battery or cell to accept a charge, influenced by factors such as cell temperature, charge rate, and the state of charge.
Charge amplifier – It is an electronic circuit which converts a high-impedance charge signal from a sensor into a proportional, low-impedance voltage signal.
Charge carrier – It is a particle, such as an electron or proton, which carries electric charge through a medium, facilitating the flow of electricity and contributing to different physical processes.
Charge carrier density – It is also known as carrier concentration. It is the number of charge carriers per unit volume in a material. These charge carriers are typically electrons and holes in semi-conductors, or ions in other materials.
Charge controller – It is an electronic voltage and current regulator which sits between a power source (like solar panels) and a battery bank to prevent overcharging and deep discharging, ensuring safety and extending battery life.
Charge conveyor – It is the conveyor with steel cord rubber belt for taking charge materials to the furnace top from the stock house. Conveyor charging is alternate to skip charging.
Charge coupled device – It is a highly sensitive photon detector. It is divided up into a large number of light-sensitive small areas known as pixels, which can be used to assemble an image of the area of interest. A charge coupled device is a silicon-based multi-channel array detector of ultra-violet, visible and near-infra light.
Charge-coupled device camera – It is a digital imaging device which uses a charge-coupled device (CCD) sensor to convert incoming light into electronic signals.
Charge cycle – It is the process of completely charging a rechargeable battery and discharging its total capacity into a load, whether done all at once or spread across multiple partial sessions.
Charged accumulator – It is a storage device in a hydraulic system which stores fluid at a needed pressure, allowing for the release of this fluid to meet actuator demands, hence reducing pump size and power requirements. It typically operates by compressing gas, with the most common type being a gas-filled bladder accumulator.
Charge decay – It is the process by which an electrostatic or electric charge on the surface or inside a material decreases and dissipates over time.
Charge density – It is the measure of the quantity of electric charge distributed per unit length, surface area, or volume. Volume charge density is the charge per unit volume, used for 3D objects like bulk materials or dielectrics. Surface charge density is the charge per unit area, used for 2D sheets or the surface of conductors. Linear charge density is the charge per unit length, used for 1D objects like thin wires.
Charge depleting mode – It refers to the operational state of a plug-in hybrid electric vehicle (PHEV) where the vehicle predominantly uses power from the battery pack, with additional support from the internal combustion engine (ICE) as needed, mainly for propulsion or battery charging.
Charge diameter – It refers to the physical width or diameter of a cylindrical explosive or propellant charge. It is the lateral cross-sectional diameter of an explosive column or stick used in mining, demolition, or ordnance.
Charged jet – It is a fluid jet which carries an electric charge, influenced by fluid parameters and process parameters, and its behaviour can be analyzed through equations derived from Coulomb’s law and other control models. It also refers to a collimated cone of hadrons produced during high-energy particle collisions.
Charged liquid jet – It is a high-velocity stream of fluid which has been given a net electric charge.
Charged object – It is an item which has a net electric charge since it contains an unequal number of protons (positive particles) and electrons (negative particles).
Charged species – These are ions, electrons, or molecular fragments which carry a net positive or negative electric charge and actively participate in physical, chemical, or electrical processes.
Charged surface – It in engineering is a material boundary or membrane treated with chemical functional groups or ions to hold a net positive or negative electrostatic charge. Surface charge engineering is the deliberate modification of this boundary to control interfacial properties like ion selectivity, wetting, and energy harvesting.
Charge injection – It is the process of introducing additional charges into a dielectric material, often through methods such as plasma treatment or ionized-air guns, to enhance the surface charge density and improve the performance of devices like tribo-electric nano-generators (TENGs). Charge injection is also an unwanted parasitic effect where a control signal changing state on an analog switch or MOSFET (metal–oxide–semiconductor field-effect transistor)pushes a small burst of electrical charge into the main signal path, creating a voltage spike or error.
Charge mode – It refers to a type of accelerometer which uses an external charge amplifier or in-line impedance converter to sense the charge generated by the strain of a piezoelectric crystal, with output measured in pico-coulombs. It is characterized by its ruggedness and reliability because of due to its simple design and construction.
Charge output – It is the short-circuit charge generated by a tribo-electric nano-generator (TENG) during a half cycle under short circuit conditions, ideally occurring without impedance in the loop.
Charge pressure – It refers to the baseline or preparatory fluid pressure / gas pressure supplied to a system, such as a hydraulic transmission or a gas accumulator, to keep it operational, prevent damage, and maintain proper flow.
Charge pump – It is a direct current / direct current (DC / DC) charge converter which raises a lower voltage magnitude by utilizing the energy storage capabilities of capacitors, achieving efficiencies of up to 90 % to 95 %. It operates on specific semi-conductor technologies designed to draw minimal current from a source, facilitating applications such as voltage boosting for power management systems. Charge pump also means a secondary fluid pump which feeds oil or fluid under pressure into a main pump to prevent cavitation.
Charge pump circuit – It is a type of circuit which uses capacitors to achieve higher output voltages by alternating between a charging state and a charge transfer state, allowing it to double the input voltage or provide integer multiples of it.
Charger – It is used to transport material to and from the press or a conversion equipment. Charger is an integral part of any conversion process. It needs to have the ability to efficiently transfer material to and from the conversion equipment. The types of chargers are mobile chargers and conveyer systems. Floor charger is, by far, very common. Rail-bound floor charger is also available. Overhead charger is similar to floor chargers, except that it is suspended from a rail system, similar to that of an overhead crane. The flexibility of mobile charger makes it well suited to typical forging operations which need several furnaces and a variety of work-stations. Charger is also a device which is used to put electricity into a re-chargeable battery.
Charge regulation – It is a physicochemical phenomenon where the effective electrical charge on a surface or macro-molecule changes dynamically in response to its local chemical environment, such as pH or ion concentration. It occurs when ionizable groups on a surface (like polymers, or colloidal particles) gain or lose protons / ions depending on the surrounding solution.
Charge storage – It is the mechanism or ability of a system, material, or device to accumulate, retain, and later release electrical charge or electrochemical energy.
Charge-sustaining mode – It is an operational state in hybrid and plug-in hybrid electric vehicles (PHEVs) where the vehicle maintains a relatively stable battery state of charge (SOC) over a driving cycle.
Charge transfer resistance – It is the electrical resistance encountered by electrons or ions as they move across the boundary between an electrode and an electrolyte during an electrochemical reaction. It measures how sluggish or fast an electro-chemical reaction is at the surface.
Charge-transfer salt – It is an ionic molecular material formed when an electron is completely transferred from an electron donor molecule to an electron acceptor molecule, creating a stable, electrically conductive crystalline lattice.
Charge transport – It refers to the movement of charge carriers, such as electrons, electron holes, and ions, through a material or device under the influence of an electric field or concentration gradient.
Charging – For a lap, it is impregnating the surface with fine abrasive. It is also placing materials into a furnace.
Charging basket – It also called a scrap charging bucket or material basket. It is a heavy-duty, industrial container used to load, transport, and deposit raw materials, most notably scrap metal, direct reduced iron (DRI), and alloys, directly into a smelting furnace.
Charging box – It is also frequently referred to as a charging bucket or scrap basket. It is a heavy-duty, heat-resistant metal container used to transport, hold, and dump raw materials, known as the ‘charge’, into a smelting furnace.
Charging bucket – It is also known as a scrap basket. It is a heavy-duty, large-capacity steel vessel used to collect, weigh, transport, and deposit scrap metal or other raw materials into a melting furnace. It is a foundational piece of material-handling equipment mainly used in electric arc furnace (EAF) steelmaking and foundry operations.
Charging crane – It is a heavy-duty overhead bridge crane used to transport raw materials, scrap metal, or molten liquid metal and charge them directly into a furnace.
Charging device – It is an apparatus which supplies electrical current to replenish the energy in a rechargeable battery.
Charging door – It is a specialized, heat-resistant hatch or portal on a metallurgical furnace (such as a cupola, or electric arc furnace). It opens to allow workers or mechanical loaders to add raw materials, like metal scrap, pig iron, coke, and fluxes, into the heating chamber.
Charging energy – It is the electrostatic energy or power needed to add electrons or transfer electrical power into a system, such as a quantum device, an electro-catalytic material, or a battery energy storage unit.
Charging equipment – It is the equipment used for charging of materials at the top of the blast furnace without allowing escape of blast furnace gas to the atmosphere.
Charging floor – It is an elevated working platform or staging built around a melting or reduction furnace (such as a cupola, or electric furnace) at the level of the furnace’s charging door. It provides a safe space for operators, mechanical cranes, and automated chutes to load raw materials, like metal scrap, coke, and fluxes, into the furnace.
Charging infrastructure – It refers to the physical networks, equipment, and facilities used to supply electrical energy to electric vehicles (EVs).
Charging machine – It is a mechanical device used to feed raw materials, such as metal scrap, ore, coke, or flux, safely and efficiently into a smelting or melting furnace.
Charging materials – These are the raw inputs, metals, fuels, and chemical additives loaded into a furnace to be melted, smelted, or refined into a specific alloy or metal grade.
Charging mechanism – It is a process or system used to transfer electrical energy, or build static charge.
Charging process – It is the method of transferring electrical energy or electric charge to an object, device, or battery.
Charging temperature – It is the safe and effective ambient or internal temperature range (typically between 0 deg C and 45 deg C for lithium-ion batteries) needed to add energy to a device or system without causing permanent damage or safety hazards.
Charging time – It is the total length of time needed to refill a battery from an empty or partially discharged state to a full charge.
Charging voltage – It is the electrical pressure supplied by a charger or power source to push energy back into a battery.
Charles’s law – It is an experimental gas law which describes how gases tend to expand when heated. A modern statement of Charles’s law is ‘when the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume is in direct proportion. This law describes how a gas expands as the temperature increases, conversely, a decrease in temperature leads to a decrease in volume. For comparing the same substance under two different sets of conditions, the law also shows that, as absolute temperature increases, the volume of the gas also increases in proportion.
Char oxidation – It is a heterogeneous gas-solid chemical reaction where the solid, carbon-rich residue of pyrolysis (char) reacts with gaseous oxygen to produce carbon mono-oxide (CO) and carbon di-oxide (CO2).
Char particles – These are volatile-free carbon and ash remnants which result from the devolatilization process and are involved in the burning phase within a fluidized bed, where they undergo oxidation reactions influenced by mass and heat transfer phenomena. These are formed after a carbon-containing material (like coal, biomass, or petroleum coke) undergoes devolatilization or pyrolysis.
Charpy – It refers to a standardized high strain-rate test which determines the quantity of energy absorbed by a material during fracture, serving as a measure of the material’s notch toughness and aiding in the study of temperature-dependent ductile-brittle transition.
Charpy impact test – It is also called Charpy test or Charpy notch test. It is a test in which a V-notched, keyhole-notched, or U-notched sample, supported at both ends, is struck behind the notch by a striker mounted at the lower end of a bar which can swing as a pendulum. The energy which is absorbed in fracture is calculated from the height to which the striker would have risen had there been no sample and the height to which it actually rises after fracture of the sample.
Charpy impact testing – It is a standardized high-strain-rate test which measures the quantity of energy a material absorbs when fractured by a swinging pendulum.
Charpy impact toughness – It is the measure of the quantity of energy a material absorbs when it breaks under a sudden, high-speed impact.
Charpy test – It is a standardized high strain-rate test which measures the quantity of energy absorbed by a material during fracture, providing an indication of its notch toughness and aiding in the study of temperature-dependent ductile-brittle transitions.
Charpy toughness – It is the measure of a material’s ability to absorb energy during fracture, typically assessed through Charpy impact tests at specified temperatures, with minimum values based on historical data indicating reduced risk of brittle fracture in service.
Char reaction rate – It is the speed at which solid carbonaceous char (formed from coal or biomass pyrolysis) is consumed by a gasifying agent like oxygen, steam, or carbon di-oxide to produce gaseous fuels.
Char reactivity – It is the speed and ability of a solid carbon residue, called char, to react with gases like oxygen, carbon di-oxide, or steam during combustion or gasification. It measures how easily char undergoes chemical changes when exposed to reactants.
Char residue – It is the solid, carbon-rich leftover material produced when organic matter (such as biomass, plastics, or polymers) undergoes thermal degradation, pyrolysis, or incomplete combustion without enough oxygen.
Charring – It is the heating of a composite in air to reduce the polymer matrix to ash, allowing the fibre content to be determined by weight.
Char surface -It refers to the outer porous layer of carbonized (char) residue formed when organic materials or composites undergo thermal decomposition, pyrolysis, or burning.
Chart recorder – It is an electro-mechanical device used to capture and display electrical or physical process variables as a continuous graphical plot over time.
Chase (machining) – It is to make a series of cuts each, except for the first, following in the path of the cut preceding it, as in chasing a thread.
Chasing – It is a traditional metalworking technique used to detail, crisp, or refine the front side of a metal object.
Chat session – It is a real-time exchange of messages between parties using a chat application, where all interactions can be logged and recorded for later reference.
Chatter – In machining or grinding, (i) it is a vibration of the tool, wheel, or work-piece producing a wavy surface on the work, and (ii) the finish produced by such vibration. tribology, it is the elastic vibrations resulting from frictional or other instability.
Chatter marks – These are surface imperfections on the work being ground, normally caused by vibrations transferred from the wheel-work interface during grinding.
Chaudron diagram – It is also known as a Baur-Glassner diagram, is a phase diagram specific to the Fe-O-C-H system. It graphically represents the stability regions of different iron phases (like iron, wustite, and magnetite) as a function of temperature and the oxidizing power of the surrounding gas, especially in the presence of hydrogen and / or carbon mono-oxide. The diagram helps predict the conditions under which different iron phases are stable and can be used to understand the reduction of iron oxides in several industrial processes.
C-H bond activation – It refers to synthetic methods which enable the transformation of sp3 and sp2 C-H bonds into more reactive species, facilitating the formation of C-C and C-heteroatom bonds.
Chebyshev filters – These are analog or digital signal-processing filters which provide a steeper roll-off (sharper transition) than Butterworth filters by allowing uniform amplitude variations, called ripples, in either the pass-band or the stop-band. These filters minimize the error between an ideal filter and an actual filter response over a specific frequency band, making them ideal when sharp frequency discrimination is needed.
Chebyshev’s Inequality – It states that for any probability distribution with a known mean and finite variance, the probability which a random variable deviate from the mean by ‘k’ or more standard deviations is no more than 1/k-square.
Chebyshev type – It refers to a class of filters, specifically the Chebyshev type-2 filter, which is characterized by a maximally flat pass-band and an equal-amplitude ripple in the stop-band, allowing for specified frequency settings for the start of the stop-band and maximum ripple amplitude.
Check – It is the intermediate section of a flask which is used between the cope and the drag when moulding a shape that requires more than one parting plane. It is also a crack in a die impression corner, normally because of the forging strains or pressure, localized at some relatively sharp corner. Die too hard for the depth of the die impression have a tendency to check or develop cracks in impression corners. Check is also one of a series of small cracks resulting from thermal fatigue of hot forging dies.
Check dam – It is a small dam to decrease the stream-flow velocity, minimize channel erosion, promote deposition of sediment, and to divert water from a channel.
Checked edges – These are sawtooth edges seen after hot rolling and / or cold rolling.
Checker refractories – A checker brick is a kind of heat carrier with features of good volume stability, excellent high temperature load creep property, high density and low apparent porosity for such applications as in hot blast stove of blast furnace and flame furnace. It consists of fluted and parallel-bored hexagonal bricks, which is stacked in the regenerator. The important features of the checker bricks are (i) good volume stability, (ii) good high-temperature loading creep property, (iii) high bulk density, and (iv) low apparent porosity. The size of the checker brick hole depends not only on the dust content of the combustion gas, but also on the air volume in the production. High performance checkers feature optimum heat transmission characteristics (heating surface) and heat storage capacity (refractory weight) over a very long service life.
Checkers – In a chamber associated with a metallurgical furnace, it is the bricks stacked openly so that heat can be absorbed from the combustion products and later transferred to incoming air when the direction of flow is reversed.
Checking – It is the development of slight breaks in a coating which do not penetrate to the underlying surface.
Check list – It is tool used to ensure that all important steps or actions in an operation have been taken. Check lists contain those items which are important to the situation.
Check matrix – It is a matrix used in coding theory, specifically for linear codes, which helps to verify the integrity of a code-word by determining its syndrome, which indicates whether the code-word is valid or has errors.
Checks – These are several, very fine cracks in a coating or at the surface of a metal part. Checks can appear during processing or during service and are most frequently associated with thermal treatment or thermal cycling. It is also called check marks, or heat checks. Checks are also minute cracks in the surface of a casting caused by unequal expansion or contraction during cooling. Checks are also cracks in a die impression corner, normally because of the forging strains or pressure, localized at some relatively sharp corner. Die blocks too hard for the depth of the die impression have a tendency to check or develop cracks in impression corners. Checks are also a series of small cracks resulting from thermal fatigue of hot forging dies.
Check sheets – These are simple data gathering devices. They are used to collect data effectively and efficiently. They prepare data for further analysis. A check sheet is in the form of a designed format used to collect data in a systematic manner and in real time at the location where the data is generated. The data it captures can be either quantitative or qualitative. When the information is quantitative, the check sheet is sometimes called a tally sheet. The defining characteristic of a check sheet is that data are recorded by making marks (checks) on it. The time-oriented summary is particularly valuable in looking for trends or other meaningful patterns.
Check, switch – Switch checks refer to the process of monitoring the state of a switch, which involves determining when the switch is pressed or released to trigger specific actions in a programme, such as counting presses or controlling LED (light emitting diode) states.
Check valve – It is a one-directional valve which is opened by the fluid flow in one direction and which closes automatically when the flow stops or reverses direction.
Check valve clapper disc – It is the hinged closure element of a swing check valve.
Cheek – It is the intermediate or middle sections of a moulding flask used in a three-part mould, positioned between the top part (cope) and the bottom part (drag). It is necessitated by difficulty in moulding unusual shapes, or in cases where more than one parting line is needed.
Chelate – It is a coordination compound in which a heterocyclic ring is formed by a metal bound to two atoms of the associated ligand.
Chelate compounds – These consist of a class of coordination or complex compounds consisting of a central metal atom attached to a large molecule, called a ligand, in a cyclic or ring structure.
Chelating agent – It is an organic compound in which atoms form more than one coordinate bond with metals in solution. It is also a substance used in metal finishing for controlling or eliminating certain metallic ions present in undesirable quantities.
Chelation – It is a chemical process involving formation of a heterocyclic ring compound which contains at least one metal cation or hydrogen ion in the ring.
Chemical – It is a substance which has a definite composition and is made up of matter, including all elements, compounds, liquids, gases, and solids.
Chemical absorption – It is a mass-transfer process where a substance (the absorbate) dissolves into a bulk liquid or solid phase and simultaneously undergoes a chemical reaction with the absorbing medium. Unlike physical absorption, which relies solely on solubility and physical dissolution (like gas dissolving in water), chemical absorption (or reactive absorption) forms chemical bonds, considerably increasing the capacity and rate at which a fluid can capture specific components.
Chemical absorption process – It involves one or more reversible chemical reactions between carbon di-oxide and an aqueous solution of an absorbent, such as mono-ethanol-amine based solvent, and high-performance amines (activated methyl diethanolamine) etc. Upon heating the product, the bond between the absorbent and carbon di-oxide can be broken, yielding a stream enriched in carbon di-oxide. The chemical absorption process for separating carbon di-oxide from flue gas is borrowed from the gas processing industry. Amine based processes are being used commercially for the removal of acid gas impurities (carbon di-oxide and hydrogen sulphide) from process gas streams.
Chemical abstracts service (CAS) – It is a division of the American Chemical Society which collects, organizes, and provides access to world-wide scientific and engineering literature on chemical substances.
Chemical abstracts service number – It is also called CAS number. It is a unique global numerical identifier assigned to chemical elements and compounds.
Chemical action – It refers to any process where a change in the chemical composition or molecular structure of a material occurs, frequently resulting in material degradation (such as acid erosion on concrete or steel corrosion) or serving as the foundational transformation mechanism inside industrial chemical reactors.
Chemical admixture – It is a material added to a concrete or mortar batch before or during mixing in small quantities (normally less than 5 % of cement) to modify its fresh, setting, or hardened properties.
Chemical adsorption– It is same as chemisorption which is the binding of an adsorbate to the surface of a solid by forces whose energy levels approximate those of a chemical bond.
Chemical aid – It is a substance, compound, or chemical agent used to assist, facilitate, or improve a specific process, analysis, or practical task.
Chemical analysis – It is the determination of the principal chemical constituents.
Chemical and refinery industries – These industries refer to facilities which process raw materials into valuable products, generating waste gases which can be collected and combusted for additional energy through combined heat and power (CHP) systems. These industries frequently operate at high temperatures and can supply waste heat to local district heating systems to reduce reliance on more expensive fuels and lower emissions.
Chemical attributes – These refer to important properties of molecules which can be quantitatively described using different chemical descriptors, including topological indices derived from chemical graphs. These attributes encode necessary information about the molecular structure and behaviour, facilitating predictive modelling in chemistry.
Chemical bias – It refers to the use of differing pH electrolytes in the anode and cathode chambers of an electro-chemical cell to provide a supplementary voltage boost.
Chemical bond – It is an attractive force which that links atoms or molecules together by sharing, transferring, or redistributing their valence electrons (outermost electrons) to reach a stable, low-energy state. These atomic-level interactions dictate macro-level mechanical, electrical, and thermal properties of metals, polymers, and ceramics. Chemical bond is an inorganic or organic-inorganic bond with hardening by a chemical, but not hydraulic, reaction at ambient or higher temperatures.
Chemical bonding – It is the joining together of atoms to form molecules.
Chemical bonding theory – It explains the attractive forces holding atoms, ions, or molecules together to form stable engineering materials with lower total energy.
Chemical brightening – It is a chemical treatment to improve the specular reflectivity of a surface.
Chemical burn – It is the tissue or skin damage caused by corrosive substances like acids and alkalis during industrial processes, equipment leaks, or maintenance.
Chemical characterization – It is the process of using analytical chemistry, data gathering, and testing to identify and quantify the chemical constituents of a material or product.
Chemical class – It is a grouping of chemical substances which share similar molecular structures, physical properties, reactivity, or hazard profiles.
Chemical classification – It is the systematic grouping of substances based on their molecular structure, chemical properties, reactivity, or hazard levels for ensuring safe design, processing, and material selection.
Chemical cleaning – It is the process of immersing steel in chemical solvents to remove (dissolve) residues which otherwise prevents the galvanized coating from forming.
Chemical coagulation – It is the process of adding chemicals to effluents to remove suspended solid wastes by neutralizing the repulsive electrical charges on particles, allowing them to aggregate into larger floccules for easier gravitational settling. This process is frequently used as a pretreatment step prior to further treatment methods.
Chemical commodity production – It is the large-scale, continuous manufacturing of basic, standardized chemical substances (such as ethylene, sulphuric acid, and ammonia) designed for low cost and high volume.
Chemical compatibility – It refers to the stability of materials when they are in contact with other substances, specifically the ability of substances to coexist without undergoing reactions or causing detrimental changes in their properties or the surrounding materials. In essence, it is about ensuring materials do not corrode, degrade, or react dangerously when exposed to a particular chemical environment.
Chemical components – These refer to an individual, identifiable chemical substance, element, or species which constitutes a material, mixture, or engineered system. These components influence the properties of the materials, e.g., addition of elements such as chromium and nickel to steel alters its characteristics and improves its resistance to rust.
Chemical composition – It is the identity and relative number of the elements which make up a chemical compound, which can frequently be expressed with a chemical formula.
Chemical compound – It is a chemical substance composed of several identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is hence not a compound. A compound can be transformed into a different substance by a chemical reaction, which can involve interactions with other substances. In this process, bonds between atoms can be broken and / or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds, ionic compounds are held together by ionic bonds, intermetallic compounds are held together by metallic bonds, coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case.
Chemical conditioning – It is the addition of specific chemicals to a fluid, slurry, or material to alter its properties, improve process efficiency, or prevent damage to equipment. It is widely used across water treatment, wastewater management, and power generation.
Chemical conversion coating – It is the treatment of material with chemical solutions by dipping or spraying to increase the thickness of the natural oxide film on the surface or to build up an oxide film bearing chromates or phosphates. It is also a protective or decorative non-metallic coating produced in situ by chemical reaction of a metal with a chosen environment. It is frequently used to prepare the surface prior to the application of an organic coating.
Chemical cost – It refers to the purchasing expense of raw material feedstocks, reactants, catalysts, and solvents needed to manufacture a product.
Chemical crosslinking – It is the process of forming permanent covalent bonds between adjacent polymer chains to create an inter-connected, three-dimensional network.
Chemical damage – It is the progressive deterioration or structural weakening of a material caused by chemical reactions between the material and its environment (such as acids, alkalis, solvents, or reactive gases).
Chemical decomposition – It is the breakdown of a single particle or entity (such as a molecule or reactive intermediate) into two or more fragments, or a chemical reaction in which two or more products are formed from a single reactant.
Chemical degassing – It is the removal of unwanted dissolved gases, entrained air, or volatile vapours from liquids or industrial equipment using added chemical agents.
Chemical degradation – It is the irreversible breakdown or deterioration of a material’s structure and properties caused by chemical reactions with its operating environment.
Chemical deposition – It is the precipitation or plating-out of a metal from solutions of its salts through the introduction of another metal or reagent to the solution.
Chemical diffusion – It is the spontaneous transport of atoms, molecules, or ions from a region of higher concentration to a region of lower concentration, driven by thermal energy and random molecular motion.
Chemical driving force – It refers to the change in Gibbs-energy associated with the formation of a new phase in a system, indicating the tendency of a reaction to proceed. It can be expressed as the difference between the Gibbs energy of the new phase and the extrapolated Gibbs energy of the existing phase, signifying the direction and extent of phase transformation.
Chemical effects – These refer to the modifications occurring at the metal-to-electrolyte interface because of the cathodic reactions, which include oxygen consumption, production of alkalinity, and the formation of metal oxides or hydroxides. These effects can lead to protective deposits, such as calcareous deposits in seawater applications, which improve the corrosion protection of metallic structures. The chemical effect of electric current is the process, where passing an electric current through a conducting solution (electrolyte) causes chemical reactions and changes at the electrodes.
Chemical element – It is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus. Atoms of the same element can have different numbers of neutrons in their nuclei, known as isotopes of the element.
Chemical energy – It is the energy which is used during a metallurgical process where the exothermic chemical reactions (oxidizing of impurities in liquid metal) are utilized for supplying the necessary heat needed during the process.
Chemical energy storage – It is the process of capturing and retaining energy within the chemical bonds of substances or materials through reversible reactions, sorption, or chemical transformations, allowing it to be retrieved later as electricity, heat, or mechanical work.
Chemical engineering – It is a branch of engineering which applies physical sciences, life sciences, mathematics, and economics to design, develop, and safely operate large-scale industrial processes which convert raw materials into valuable products.
Chemical engineering design – It is the systematic process of applying physical sciences, mathematics, and economics to create, scale, and optimize industrial processes which convert raw materials into valuable products.
Chemical engineering laboratory – It is a specialized workspace where principles of chemistry, physics, and engineering are applied to test, analyze, and scale up chemical processes and materials from bench scale to pilot and industrial scales.
Chemical environment – It refers to the surrounding physical and chemical conditions, such as exposure to gases, liquids, solids, acids, or solvents, which interact with or affect materials, equipment, and structures.
Chemical equation – It is a symbolic representation of a chemical reaction in the form of symbols and formulas, where the reactant entities are given on the left-hand side and the product entities on the right-hand side.
Chemical etching – It is the dissolution of the material of a surface by subjecting it to the corrosive action of an acid or an alkali.
Chemical exergy – It is the maximum useful work obtainable from a substance as it comes into chemical equilibrium with a reference environment. It measures the work potential stored in a substance because of a difference in its chemical composition compared to the surrounding environment. Its value becomes zero when the substance is fully in chemical equilibrium with that reference environment.
Chemical feed pipe – It is a pipe inside a boiler drum through which chemicals for treating the boiler water are introduced.
Chemical fertilizer – It is an inorganic, synthetically manufactured or industrially processed compound designed to supply plants with high concentrations of necessary macro-nutrients, mainly nitrogen (N), phosphorus (P), and potassium (K), to restore soil fertility.
Chemical fibre – It is a man-made fibrous material manufactured industrially from organic or inorganic polymers through chemical and mechanical processes.
Chemical film binder – A chemical film binder coats the particles of a material with a thin film and causes a brief chemical reaction which bonds the particles together. when a chemical film binder is used, the resulting briquette is frequently water-proof. Examples of chemical film binders are sodium silicate and dilute acid, or sodium silicate and lime.
Chemical fingerprint – It is a computer-readable digital representation of a molecule’s structure, typically formatted as a binary string (sequence of 1s and 0s) or bit vector indicating the presence or absence of specific chemical substructures or features.
Chemical finishing – It is the application of chemical treatments to a material’s surface or structure to impart specific functional and aesthetic properties.
Chemical flood – It is a method in improved oil recovery which involves injecting chemicals, such as polymers or surfactants, into a reservoir to improve fluid flow and reduce residual oil saturation. This process includes techniques like polymer flooding, micellar–polymer flooding, and alkaline flooding, which improve displacement efficiency by modifying the properties of the injected fluids.
Chemical flux cutting – It is an oxygen-cutting process in which metals are severed using a chemical flux to facilitate cutting.
Chemical footprint – In environmental assessment measures, It is the total mass and potential toxicity of hazardous chemicals used or emitted by a product, process, facility, or organization.
Chemical formula – It is a way of presenting information about the chemical proportions of atoms which constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs. These are limited to a single typographic line of symbols, which can include subscripts and superscripts. A chemical formula is not a chemical name since it does not contain any words. Although a chemical formula can imply certain simple chemical structures, it is not the same as a full chemical structure formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are normally more limited in power than chemical names and structural formulae. The simplest types of chemical formulae are called empirical formulae, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulae indicate the simple numbers of each type of atom in a molecule, with no information on structure. For example, the empirical formula for glucose is CH2O (twice as many hydrogen atoms as carbon and oxygen), while its molecular formula is C6H12O6 (12 hydrogen atoms, six carbon and oxygen atoms).
Chemical hardening – It is a surface-treatment process which alters the chemical composition of a metal’s outer layer to increase its hardness, wear resistance, and strength while keeping the interior core tough and ductile.
Chemical hazards – These refer to solid, liquid, or gaseous substances whose intrinsic chemical properties can cause physical injury, adverse health effects, or environmental damage.
Chemical heating – It refers to the release or generation of thermal energy through exothermic chemical reactions (such as oxidation or hydration) rather than by external electrical or mechanical power sources.
Chemical heat pipe – It is an energy transport and storage system which uses reversible chemical reactions instead of simple phase changes to carry high-temperature heat over long distances.
Chemical hydride – It is a compound which stores hydrogen through chemical bonds and releases it as a gas when heated, mixed with water, or exposed to a catalyst.
Chemical hydrogen storage – It is the technology of binding hydrogen atoms covalently or through chemical reactions into liquid or solid carrier compounds (such as chemical hydrides, ammonia borane, or liquid organic hydrogen carriers), allowing hydrogen to be stored, transported safely under mild conditions, and released on demand through thermal decomposition or catalytic reactions.
Chemical inhibitor – It is a substance added in small quantities to a system to slow down, reduce, or completely stop an unwanted chemical reaction, corrosion, or material degradation.
Chemical inertness – It refers to a material’s ability to remain stable and resist chemical reactions, corrosion, or degradation when it comes into contact with other substances under specific operating conditions.
Chemical kinetic modelling – It is the process of building mathematical representations to predict how fast chemical reactions occur and how chemical systems change over time under varying conditions like temperature, pressure, and concentration.
Chemical kinetics – It is also known as reaction kinetics. It is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a reaction occurs but in itself tells nothing about its rate.
Chemical laboratory – It is a controlled workspace equipped for conducting scientific experiments, analyses, and research in chemistry.
Chemical linkers – These are low-molecular bi-functional molecules which tether biomolecules to solid or liquid transducer surfaces, providing suitable docking sites and reducing the risk of electrical flaws at the surface. These linkers often contain different terminal functional groups which facilitate covalent bonding in the formation of bio-thin films.
Chemical looping combustion – It is an innovative energy technology which burns fuel using a solid metal oxide instead of direct air, allowing for inherent and low-cost carbon di-oxide capture. The system uses two interconnected reactors, normally fluidized beds, called the air reactor and the fuel reactor.
Chemical looping gasification – It is an advanced thermo-chemical process which converts solid carbonaceous materials, such as bio-mass or coal, into high-quality, nitrogen-free syngas (a mixture of hydrogen and carbon mono-oxide) by using a solid metal oxide oxygen carrier instead of pure molecular oxygen or air.
Chemical looping partial oxidation – It is a clean technology used to convert carbon-based fuels into syngas (a mix of hydrogen and carbon mono-oxide) or pure hydrogen by using solid metal oxides as oxygen carriers.
Chemical looping reforming – It is a clean chemical process which converts hydrocarbon fuels like natural gas into synthesis gas (a mix of hydrogen and carbon mono-oxide) without using pure oxygen.
Chemically active gas – It is a gaseous substance which readily participates in chemical reactions with surrounding materials, molten metals, or surfaces under specific operational or thermal conditions, rather than remaining inert. In fields like metal active gas (MAG) welding and plasma technology, these gases break down under high heat or electrical arcs to actively alter the chemical and mechanical properties of a workpiece or weld pool.
Chemically assisted surface engineering – It is also widely referred to as chemically assisted surface enhancement. It is a two-stage metallurgical surface treatment process. It sequentially combines controlled shot peening with isotropic vibratory super-finishing to drastically extend the fatigue life, reduce friction, and enhance the wear resistance of critical metal components. The main goal of chemically assisted surface engineering (CASE) is to achieve a dual benefit that traditional, singular processes cannot: a mirror-like isotropic finish while simultaneously embedding deep subsurface residual compressive stresses.
Chemically bonded brick – It is the brick manufactured by processes which do not involve firing of the finished product.
Chemically bonded ceramics – These are advanced materials formed through low-temperature chemical reactions, typically acid-base interactions between a ceramic powder base and a liquid activator, rather than high-temperature firing.
Chemically bonded phosphate ceramics – These are advanced inorganic composite materials formed through low-temperature chemical reactions, typically an acid-base reaction between a metal oxide powder and a phosphate solution, rather than traditional high-temperature sintering.
Chemically precipitated metal powder – It is the powder produced by the replacement of one metal from a solution of its salts by the addition of another element higher in the electro-chemical series, or by other reducing agent.
Chemically precipitated powder – It is a metal powder which is produced as a fine precipitate by chemical displacement.
Chemical machining – It consists of removing the metal stock by controlled selective chemical dissolution.
Chemical matrix binders – A chemical matrix binder uses a chemical reaction between two binder components for binding the material particles together. Examples of chemical matrix binders are quick lime (CaO) and water, molasses and slaked lime, and water and Plaster of Paris.
Chemical mechanical planarization – It is also called chemical mechanical polishing. It is a manufacturing process which uses a mix of chemical reactions and mechanical rubbing to flatten and smooth the surface of semi-conductor wafers.
Chemical mechanical polishing – It is a manufacturing process which uses a mix of chemical reactions and mechanical force to make a surface very flat and smooth.
Chemical mechanism – It is the detailed, step-by-step sequence of elementary molecular reactions, intermediates, and energy pathways that turn reactants into products. Chemical mechanisms refer to detailed representations of all species and reactions at the molecular level, which can be simplified to skeletal mechanisms by eliminating unimportant species and reactions, and further reduced to potentially include nonelementary reactions and algebraic constraints.
Chemical metallurgy – It is the science and technology of winning metals from their ores and purifying metals. Its two chief branches are extractive metallurgy and refining.
Chemical milling – It is the machining process in which metal is formed into intricate shapes by masking certain portions and then etching away the unwanted material. It is the controlled dissolution of workpiece material through contact with a chemical solution, typically composed of strong inorganic acids or bases, to remove material from a surface in a manner which mimics machining processes.
Chemical oxidation – It is a chemical reaction where an atom, ion, or molecule loses electrons, resulting in an increase in its oxidation state.
Chemical oxygen demand – It is an indicative measure of the quantity of oxygen which can be consumed by reactions in a measured solution. It is normally expressed in mass of oxygen consumed over volume of solution, which is milligrams per litre. A chemical oxygen demand test can be used to quickly quantify the quantity of organics in water. The most common application of COD is in quantifying the quantity of oxidizable pollutants found in surface water (e.g., lakes and rivers) or wastewater. Chemical oxygen demand is useful in terms of water quality by providing a metric to determine the effect an effluent has on the receiving body, much like biochemical oxygen demand (BOD).
Chemical patterning – It is the controlled deposition, modification, or reaction of specific molecules onto a substrate to create well-defined surface areas with contrasting chemical properties.
Chemical plant i- It is a large-scale industrial system designed to transform raw materials into valuable chemical or biological products through coordinated physical and chemical processes.
Chemical polishing – It is a process which produces a polished surface by the action of a chemical etching solution. The etching solution is compounded so that peaks in the topography of the surface are dissolved preferentially.
Chemical potential – In a thermodynamic system of several constituents, it is the rate of change of the Gibbs function of the system with respect to the change in the number of moles of a particular constituent.
Chemical precipitation – It is the process of converting dissolved substances in a liquid into solid particles by adding specific chemical reagents to lower their solubility. The resulting solid, called a precipitate, then separates from the liquid through settling, sedimentation, or filtration.
Chemical pretreatment – It is a preparatory process which uses chemical agents to modify, clean, or break down a feed material, water stream, or metal surface to make subsequent core operations more efficient.
Chemical process – It is a method or means of changing one or more chemicals or chemical compounds in any way, either naturally or artificially, spontaneously or by the actions of external forces. In chemical engineering, it is a method used on an industrial scale (especially in manufacturing) to change the composition of one or more chemicals or materials.
Chemical production – It is the processes and operations involved in the manufacturing of chemicals and their derivatives, categorized into different us groups such as inorganic and organic chemicals, pesticides, fertilizers, and petroleum refining. It is the large-scale, industrial manufacturing of chemicals and their derivatives by transforming raw materials through controlled chemical and physical processes.
Chemical protective clothing – It is specialized personal protective equipment (PPE) designed to shield workers from hazardous chemical, physical, and biological agents by acting as a final barrier against skin contact, absorption, or inhalation.
Chemical pulping – It is a process which breaks down the chemical structure of lignin to render it soluble, allowing for the extraction of cellulose fibres, resulting in the production of chemical pulp. It separates cellulose fibres from raw plant materials by dissolving using chemical reagents under high heat and pressure. This method typically yields stronger paper with more uniform properties compared to mechanical pulping and is often associated with the Kraft process.
Chemical quenching – It refers to the rapid stopping or suppression of a chemical reaction, reactive intermediate, or an excited molecular state by adding a chemical reagent or changing local conditions.
Chemical rate theory – It defines how fast chemical reactions occur and what factors control their speed to design and optimize industrial chemical reactors.
Chemical reaction – It is a process which leads to the chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated.
Chemical reaction binders – A chemical reaction binder uses a chemical reaction to form a strong bond between the material particles to be briquetted and the binder. Examples of the chemical reaction are electric arc furnace dust mix with a water and quick lime binder, and power plant fly ash (which contains lime) mixed with water. A reagent such as dilute sulphuric acid or phosphoric acid is sometimes added to cure the strength of the briquette.
Chemical reaction engineering – It is a specialized field which focuses on the study of chemical reactions and the design, operation, and optimization of chemical reactors. It acts as a bridge between laboratory chemistry and full-scale industrial manufacturing.
Chemical reaction inclusions – These inclusions are the products of inclusion modification when calcium (Ca) treatment is improperly performed.
Chemical reaction pathways – Thee refer to sequences of individual chemical reactions which explain how specific reaction products are formed from initial materials. These pathways can be inferred from empirical data and knowledge about chemical reactions, frequently favouring those with the fewest steps based on existing heuristics.
Chemical reaction rate – It is the number of moles of a chemical species which react, form, or disappear per unit time and per unit volume (or surface area / catalyst mass). It measures how fast a reactant is consumed or a product is generated.
Chemical reaction system – It refers to a system where chemical reactions take place to convert feed materials into manufactured products. It combines chemical reactions with mass transfer, heat transfer, and fluid flow processes to convert raw materials into desired products safely and efficiently. Measurements of concentrations during these reactions are important for efficient operation and can be used for process monitoring, control, and optimization.
Chemical reaction temperature – It is the absolute thermal state of the reacting mixture which dictates the kinetic rate of molecular transformations and governs thermodynamic equilibrium inside a reactor.
Chemical reactors – These are vessels or systems designed to facilitate chemical reactions, with different types such as continuous stirred tank reactors (CSTR) and plug flow reactors (PFR) which differ in performance based on stoichiometry and kinetics. Continuous stirred tank reactors excel in heat and mass transfer, while Plug flow reactors typically provide better productivity and yield, particularly at high conversion rates.
Chemical recuperation – It is a process which captures waste heat, typically from turbine exhaust or high-temperature engine components, and uses it to drive an endothermic chemical reaction (such as fuel reforming) which upgrades a low-energy fuel into a higher-energy synthesis gas before combustion.
Chemical reduction – It is a process where a chemical species gains electrons, resulting in a decrease in its oxidation state.
Chemical reduction reaction – It is a process which involves the gain of electrons or a decrease in oxidation state by a chemical species, frequently utilized in the preparation of materials, such as crystalline nano-materials
Chemical reforming – It is a chemical process which rearranges the molecular structure of hydrocarbons to improve their properties, such as increasing the octane rating of gasoline or producing hydrogen gas.
Chemical resistance – It is the ability of a material to retain utility and appearance following contact with chemical agents. Chemical resistance properties include stain resistance, swelling resistance, moisture resistance, and corrosion resistance etc.
Chemical safety – It is the practice of designing systems, facilities, and processes to prevent harm from hazardous chemical substances to human health and the environment.
Chemical safety report – It is a formal compliance and risk assessment document that outlines the properties, hazards, safe exposure limits, and chemical safety report overview risk management measures (RMM) for a chemical substance throughout its lifecycle. It is a document prepared by REACH (registration, evaluation, authorization and restriction of chemicals) registrants which outlines the outcomes of chemical safety assessments, including risk management measures and exposure scenarios, essential for compliance with the registration, evaluation, authorization and restriction of chemicals (REACH) regulation.
Chemical sensing system – It is an integrated arrangement of components designed to detect, measure, and analyze chemical substances and convert that chemical information into a usable, measurable signal.
Chemical sensors – These are devices which measure the physical and chemical properties of an analyte and convert this into a measurable signal, with the signal magnitude typically proportional to the analyte concentration. These devices detect a specific chemical substance in a gas, liquid, or solid sample and converts that chemical information into a measurable electrical, optical, or acoustic signal. These devices are sensitive enough to detect very small quantities of analyte and can identify single molecules.
Chemical separation – It is a mass-transfer process used to divide a mixture of substances into two or more distinct product streams with specific purities or compositions.
Chemical shielding anisotropy – It is the change in how electrons shield an atomic nucleus from an external magnetic field depending on the orientation of the molecule.
Chemical shift – It is the change in the resonant frequency of an atomic nucleus relative to a standard reference molecule, caused by its unique local electronic environment in a magnetic field. This concept is fundamental for analyzing molecular structures using nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI).
Chemical shift anisotropy – It is the directional dependence of a nucleus’s magnetic shielding environment, meaning the resonant frequency of a nucleus in a magnetic field changes depending on how the molecule is oriented relative to that field.
Chemical shift tensor – It is a second-rank mathematical tensor (a 3×3 matrix) which describes how the local electronic environment around an atomic nucleus modifies its response to an external magnetic field.
Chemical shift value – It measures the resonant frequency difference of a nucleus relative to a reference standard, expressed in parts per million (ppm).
Chemical shrinkage – It is the absolute internal volume reduction which happens when reactants (such as cement and water) turn into hydration products during a chemical reaction. The total volume of the solid hydration products is smaller than the combined initial volume of the dry cement and the mixing water. This occurs since water molecules become chemically bound in a denser state than when they have been free.
Chemical solvent process – It is a separation or purification method where a liquid or gaseous solvent selectively dissolves a specific component from a mixture through a reversible chemical reaction or high chemical affinity.
Chemical species – It is a distinct form of a chemical substance or particle, such as an atom, molecule, ion, or radical, sharing identical electronic, oxidation, and structural configurations. Tracking of individual chemical species is necessary for mass balances, reaction kinetics, and reactor design.
Chemical species flow – It is the rate at which a specific, distinct chemical component moves through a processing system over time. Unlike total mass flow, which measures the bulk weight of everything moving through a pipe or conveyor, species flow tracks individual elements, ions, or molecules.
Chemical stability – It is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. Informally, it can instead refer to kinetic persistence, the shelf-life of a metastable substance or system, i.e., the timescale over which it begins to degrade.
Chemical strain-measurement methods – These refer to indirect techniques which determine physical deformation (strain) or microstructural stress in a metal by analyzing chemical reactions, phase modifications, composition shifts, or environmental degradation resulting from that strain. Unlike traditional mechanical methods (like foil strain gauges) or optical methods (like digital image correlation), chemical strain analysis leverages the concept that mechanically straining a crystalline metal lattice alters its local chemical energy, reactivity, and phase stability.
Chemical stress – It is the stress in the material because of chemical attack. In refractories, the property related to chemical stress is important for having resistance against chemical attack by slags, liquid materials, gases, and flue dust which the refractories come in contact during service. The important refractory properties for meeting the chemical stresses are chemical composition, mineralogical composition and crystal formation, pore size distribution and types of pores, gas permeability and resistance to slag, glass melts, gases and vapours.
Chemical structure – It is the specific arrangement of atoms and chemical bonds within a molecule or crystal. Tis internal arrangement determines how a material behaves, including its strength, melting point, and conductivity.
Chemical substance – It is a form of matter that has constant chemical composition and characteristic properties and which cannot be separated into simpler components by purely physical methods (i.e. without breaking chemical bonds). It is frequently called a pure substance to distinguish it from a mixture.
Chemical symbol – It is a one-letter, two-letter, or three-letter code used to represent a chemical element.
Chemical system – It is the interconnected networks of reactions, separations, heat exchanges, and controls designed to convert raw materials into products, while also considering efficiency, economic aspects, and environmental impacts. It is a specific portion of matter or a network of interacting molecules chosen for study, isolated arbitrarily from the rest of the universe (its surroundings).
Chemical tanker – It is a cargo vehicle or ship designed to transport liquid chemicals and other sensitive bulk liquids safely.
Chemical technology – It is the practical use of chemistry and engineering to turn raw materials into useful products on a large industrial scale.
Chemical thermodynamics – It is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics.
Chemical threshold – It is the specific dose, concentration, or exposure level of a chemical substance below which no adverse or harmful health effects are detected, and above which risks or observable reactions occur.
Chemical trapping – It is a permanent or semi-permanent containment process where reactive molecules or fluids undergo chemical reactions with surrounding materials to convert into stable, immobile, or less harmful compounds.
Chemical treatment – It is a process which uses chemicals to modify the characteristics of substances, or to convert hazardous waste into less harmful substances. Chemical treatments can be used in a variety of applications, including waste-water treatment, polymer surface modification, and water treatment.
Chemical trend – It refers to the predictable, systematic variation in physical, electrical, or chemical properties of materials or compounds, frequently mapped across the periodic table, which engineers use to design, select, and scale materials for specific applications like semiconductors, catalysts, and alloys.
Chemical turbulence – It refers to a spatiotemporal chaotic state in reaction-diffusion systems where spontaneous, irregular wave fronts, rotating spiral waves, or fluctuating chemical concentrations break up and form complex, shifting patterns.
Chemical vapour deposited (CVD) carbon – It is the carbon deposited on a substrate by pyrolysis of a hydrocarbon, such as methane.
Chemical vapour deposition – The chemical vapour deposition process can be defined as the deposition of a solid on a heated surface through a chemical reaction from the vapour or gas phase. It belongs to the class of vapour-transport processes which are atomistic in nature, i.e., the deposition species are atoms or molecules, or a combination thereof. This process is a coating process, similar to gas carburizing and carbonitriding, whereby a reactant atmosphere gas is fed into a processing chamber where it decomposes at the surface of the work-piece, liberating one material for either absorption by, or accumulation on, the work-piece. A second material is liberated in gas form and is removed from the processing chamber, along with excess atmosphere gas.
Chemical vapour deposition coating – It is a thin, high-performance solid layers formed when volatile precursor gases react or decompose on a heated metal substrate’s surface. It is a thin film deposition technique where materials are deposited from the vapour phase through the decomposition of reactants on a substrate at high temperatures, resulting in a homogeneous and low porosity coating. This method allows for a wide range of coatings with versatile physical and chemical properties, suitable for complex shapes.
Chemical vapour synthesis – It is the process in which vapour-phase precursors are introduced into a hot-wall reactor to favour particle nucleation in the vapour phase, enabling the formation of doped or multi-component nano-particles. This method allows for the synthesis of different nano-structures, including metal oxides, with controlled properties.
Chemical waste – It is discarded, unused, excess, or residual chemical substance from industrial, manufacturing, or laboratory processes which can harm human health or the environment if managed improperly.
Chemical waste incinerator – It is a specialized high-temperature thermal engineering system designed to completely destroy hazardous, toxic, or chemically contaminated industrial by-products through controlled dry oxidation.
Chemical water treatment – It is the addition of specific chemical substances to water to alter its chemical properties, eliminate contaminants, and protect infrastructure.
Chemical waves – These refer to the propagation of a sharp boundary between reacted and unreacted chemicals in a medium, driven by an activator wave which excites the medium followed by an inhibitory wave that restores its resting state. These waves propagate with constant shape and velocity, influenced by chemical reaction rates and diffusion.
Chemical wear – It is the corrosive wear. It is the wear in which chemical or electro-chemical reaction with the environment is significant.
Chemiluminescence imaging – It is defined as a technique used to visualize the reaction zone in flames by detecting the light emitted from CH radicals (methylidyne radical),, typically at a wave-length of 430 nano-meters, utilizing specialized optical equipment and CCD (charge-coupled device) cameras to capture intensity distributions over time.
Chemiluminescence sensor – It is an analytical device which measures the intensity of light emitted during a specific chemical reaction to determine the concentration of a target substance.
Chemiresistor – It is a type of sensor which detects gas concentrations by measuring changes in electrical resistance resulting from gas molecules interacting with a sensing material. It typically consists of two inert electrodes and is characterized by low power consumption, reusability, miniaturization, and cost-effectiveness.
Chemisorption – It consists of the binding of an adsorbate to the surface of a solid by forces whose energy levels approximate those of a chemical bond. It is the process involving the formation of strong chemical bonds between specific functional groups on an adsorbent surface and contaminants, resulting in an irreversible adsorption complex which needs higher energy input compared to physisorption. It occurs prominently when the adsorbent and contaminants possess complementary chemical reactivity and functional groups, enabling covalent bonding or ion exchange reactions.
Chemist – Chemist is a graduated scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. They carefully describe the properties which they study in terms of quantities, with detail on the level of molecules and their component atoms. Chemists carefully measure substance proportions, chemical reaction rates, and other chemical properties. Chemists use their knowledge to learn the composition and properties of unfamiliar substances, as well as to reproduce and synthesize large quantities of useful naturally occurring substances and create new artificial substances and useful processes. Chemists can specialize in any number of sub-disciplines of chemistry.
Chemistry – It is the scientific study of matter, its properties, and how it changes and interacts to form new substances.
Chemistry notation – It refers to the symbolic representation of chemical elements and compounds, which is necessary for communicating chemical information and conducting calculations in the field of chemistry.
Chemometric model – It is a mathematical and statistical algorithm applied to complex chemical or spectral data to identify hidden patterns, classify materials, or predict physical properties of new samples.
Chemostat – It is a continuous-culture bio-reactor which keeps a microbial population at a stable, constant growth rate by continuously adding fresh nutrient medium while simultaneously removing an equal volume of spent culture.
Chemostat culture – It is a technique for maintaining a steady-state in a growing culture of micro-organisms under controlled conditions, where the growth rate is regulated by the feed rate of a limiting nutrient while keeping parameters like pH, temperature, and oxygen constant.
Chen correlation – It is an empirical equation to predict the two-phase heat transfer coefficient during saturated flow boiling inside vertical tubes. The correlation uses an additive superposition model. It assumes that boiling heat transfer is governed by two concurrent mechanisms namely macroscopic forced convection, and microscopic nucleate boiling.
Chen equation – It is an explicit formula used to calculate the Darcy friction factor, which is easier to apply than the implicit Colebrook equation. It incorporates the effects of pipe roughness and Reynolds number, providing a relationship between these parameters for fully developed turbulent flow.
Chen-Flynn correlation model – It is an empirical equation used to predict the friction mean effective pressure (FMEP) in internal combustion engines.
Chen method – It is used in thermal and chemical engineering to calculate two-phase convective boiling heat transfer coefficients. It is an additive model used to estimate the heat-transfer coefficient during saturated flow boiling inside tubes. It assumes that the total heat transfer is the sum of two distinct mechanisms: macroscopic forced convection and microscopic nucleate boiling. It introduces a suppression factor to account for how fast flowing liquid reduces (suppresses) bubble growth at the heated wall, alongside a Reynolds number factor for enhanced convection.
Chernoff bound – It is an exponentially decreasing upper bound on the probability which a random variable deviates far from its expected value.
Chevrel phases – These phases consist of a family of ternary molybdenum chalcogenides, typically represented by the formula MxMo6X8 (where M is a metal and X is a chalcogen like sulphur, selenium, or tellurium and Mo is molybdenum). These compounds are known for their unique properties, including superconductivity, fast ion diffusion, and potential applications in electrocatalysis and energy storage.
Chevron – It refers to a distinctive V-shaped or arrow-head pattern which appears on the fractured surface of a metal or inside a weld, pointing directly back to where the crack or break began.
Chevron conveyor belt – This belt is are highly effective for transporting sand, coal powder, grain, or other powder or granular materials or materials packed in bags or boxes on incline though they can transport coal or mineral ore just like ordinary conveyor belts. They can transport powder or granular materials on 17-degree to around 28-degree inclines and materials packed in bags or boxes on 30-degree to around 35-degree inclines.
Chevron cracks – These cracks refer to distinct V-shaped or arrow-head-shaped features which appear in materials. Depending on the context, the term describes either a macro-level surface marking left by a fast-moving brittle fracture or an internal manufacturing defect caused during metal forming or welding.
Chevron folds – These are a structural feature characterized by repeated well behaved folded beds with straight limbs and sharp hinges. Well developed, these folds develop repeated set of V-shaped beds. They develop in response to regional or local compressive stress. Inter-limb angles are normally 60-degree or less. Chevron folding preferentially occurs when the bedding regularly alternates between contrasting competences. Turbidites, characterized by alternating high-competence sand-stones and low-competence shales, provide the typical geological setting for chevron folds to occur.
Chevroning – It is also known as a central burst. It is an internal V-shaped or cup-and-cone crack which forms along the centre-line of extruded, drawn, or cold-formed metal rods and wires.
Chevron method – In the chevron method, the material is deposited by the stacker moving to and fro over the centre line of the pile. The chevron stacking method causes segregation of the material with fine particles in the central part of the pile and coarse particles on the surface and at the bottom of the pile. For ensuring proper blending, a chevron pile is hence to be reclaimed from the face of the pile, working across the entire cross section.
Chevron packing – It is a type of packing used in packing boxes consisting of a nest of ‘V’ cross-section rings. It is also termed Vee-pack.
Chevron pattern – It is a fractographic pattern of radial marks (shear ledges) which look like nested letters ‘V’. Sometimes it is called a herringbone pattern. Chevron patterns are typically found on brittle fracture surfaces in parts whose widths are considerably higher than their thicknesses. The points of the chevrons can be traced back to the fracture origin.
Chevrons – These are distinctive V-shaped or wedge-shaped markings which form on the fractured surfaces of brittle metals and materials.
Chvorinov’s rule – It is a mathematical formula used in metal casting to calculate the total time it takes for a liquid metal to completely solidify inside a mould. The rule states that a casting with a larger volume and smaller cooling surface area takes longer to freeze, meaning total solidification time is proportional to the square of the volume-to-surface-area ratio.
Chicken wire cracks – These are synonymous with craze-cracking or alligator cracking. These cracks refer to an inter-connected network of shallow, fine surface fissures on a metal casting which visually resembles the irregular hexagonal pattern of chicken wire.
Chief ray – It is a specific ray of light which originates from an off-axis point on an object and passes straight through the exact centre of an optical system’s aperture stop (and its entrance and exit pupils).
Chill – It is a metal or graphite insert embedded in the surface of a casting sand mould or core or placed in a mould cavity for increasing the cooling rate at that point. It is also white iron occurring on a gray or ductile iron casting, such as the chill in the wedge test.
Chill coating – It consists of applying a coating to a chill which forms part of the mould cavity so that the metal does not adhere to it, or applying a special coating to the sand surface of the mould which causes the iron to undercool.
Chill coils – These are the chills made of steel wire formed into helical coils or spirals.
Chilled ammonia process – It is a post-combustion carbon capture technology which uses an aqueous ammonia solution at low temperatures (typically 0 deg C to 10 deg C) to remove carbon di-oxide (CO2) from industrial flue gases.
Chilled beam – It is an energy-efficient HVAC (heating, ventilation, and air conditioning) terminal unit mounted on the ceiling which uses circulated cold water and convection to cool indoor spaces.
Chilled beam system – It is an energy-efficient HVAC (heating, ventilation, and air conditioning) technology which uses circulated water to cool or heat buildings.
Chilled cast iron – It is a type of cast iron with a hard white-iron surface and a soft gray-iron core. It is made by cooling the outer mould rapidly so carbon forms iron carbide instead of graphite flakes.
Chilled iron – It is the cast iron which is poured into a metal mould or against a mould insert so as to cause the rapid solidification which frequently tends to produce a white iron structure in the casting.
Chilled iron rolls – These are specialized metal cylinders with a hard, wear-resistant white cast iron surface and a tough, shock-absorbing gray cast iron core, produced by rapid cooling (chilling) against a mould.
Chilled water valve – It is a mechanical control device used in HVAC (heating, ventilation, and air conditioning) and industrial cooling systems to regulate the flow rate of chilled water.
Chiller – It is a mechanical system which removes heat from a liquid, typically water or a water-glycol mixture, through a refrigeration cycle, then circulates that chilled fluid to cool buildings or industrial equipment.
Chill, external – It consists of metal, graphite or carbon blocks which are incorporated into the mould or core to locally increase the rate of heat removal during solidification and reduce shrinkage defects.
Chilling – The chilling of a blast furnace hearth occurs when the temperature of the hot metal which is tapped from the furnace is very low. The chilling of a blast furnace is a very serious phenomenon which happens due to the abnormal operation of the blast furnace. The revival of a chilled blast furnace is a big and herculean task and it takes a very long time and needs a lot of patience to bring back a chilled blast furnace to normal working condition.
Chilling effect – It refers to the rapid cooling of a molten metal at the mould walls during casting, causing a localized area of faster solidification, frequently achieved by using a ‘chill’ which is a specially designed component within the mould that draws heat away from the metal, promoting directional solidification in specific parts of the casting where desired.
Chilling system – It is also called chiller system. It is a mechanical set-up which removes heat from a liquid fluid (normally water or a water-glycol mixture) through a refrigeration cycle, using that cooled fluid to provide environmental air conditioning or industrial process cooling.
Chill, internal – It consists of a metallic device / insert in moulds or cores at the surface of a casting or within the mould to increase the rate of heat removal, include directional solidification and reduce shrinkage defects. The internal chill can then become a part of the casting.
Chill nails – These are chills in the form of nails.
Chill ring – It is also called condensing ring. It is a ring-shaped metal insert placed inside a mould to cool down specific parts of the molten metal quickly. It helps control how the metal hardens, prevents shrinkage flaws, and makes the grain structure dense and strong. It is also called backing ring which is the backing in the form of a ring, normally used in the welding of pipe.
Chill test – It is a method of determining the suitability of a gray iron for specific castings through its chilling tendency, as measured from the tip of a wedge-shaped test bar.
Chill zone – It is the area of a casting in which chilling occurs, as long sharp edges or exterior corners. Chill zone is the narrow outer layer of a metal casting or igneous rock structure where rapid cooling creates a fine-grained, randomly oriented micro-structure.
Chimney – It is a vertical structure which carries smoke and gases away from the furnace and into the outside air. Chimneys are normally made of clay, masonry, or metal. They are designed to be as close to vertical as possible so that smoke flows smoothly. The space inside a chimney is called the flue. The height of a chimney affects how well it can move gases outside. The chimney effect creates a draft (buoyancy force) which pulls air into the combustion chamber.
Chimney effect – It is also known as stack effect. Natural draft in a furnace is created by chimney effect. It is the movement of air into and out of buildings through unsealed openings, chimneys, flue-gas stacks, or other purposefully designed openings or containers, resulting from air buoyancy. Buoyancy occurs because of a difference in indoor-to-outdoor air density resulting from temperature and moisture differences. The result is either a positive or negative buoyancy force. The higher the thermal difference and the height of the structure, the higher is the buoyancy force, and hence the chimney effect.
Chimney valve – It is intended to separate the blast furnace stove from the chimney. In the plenum chamber of the stove below the grid which supports the checkers are openings to the chimney and to the cold blast main.
Chinese-script eutectic – It is a configuration of eutectic constituents, found particularly in some cast alloys of aluminum containing iron and silicon and in magnesium alloys containing silicon, which resembles the characters in Chinese script.
Chip – It is the removal of extraneous metal from a casting with hand or pneumatically operated chisels. It is also a small semi-conductor wafer made of silicon which houses millions or billions of microscopic electronic components like transistors and resistors.
Chip architecture – It is the overall structural design, functional partitioning, and organization of an integrated circuit or system-on-chip (SoC). It defines how internal components, such as processor cores, memory systems, buses, and input / output interfaces, interact, process data, and meet performance, power, and area (PPA) goals.
Chip bonding – It is the essential semi-conductor packaging process of mechanically attaching and electrically connecting a bare microchip (die) to a substrate, lead frame, or circuit board. This process secures structural stability, drives heat dissipation, and creates pathways for electrical signals and power delivery.
Chip breakage – It refers to the process of producing small, handleable, and well-broken chips during machining operations, influenced by factors such as tool geometry, cutting conditions, and work material properties. Efficient chip breakage is recognized as an important machinability factor, impacting overall machining effectiveness.
Chip breaker – It is a notch or groove in the face of a tool parallel to the cutting edge, designed to break the continuity of the chip. It is also a step formed by an adjustable component clamped to the face of the cutting tool.
Chip formation – It is the process where a cutting tool applies compressive force to a work-piece, stressing the material beyond its yield point and shearing away excess metal in the form of small pieces called chips.
Chip formation zone – It is also called primary deformation zone / shear zone. It is the specific region ahead of a cutting tool where work-piece material undergoes intense plastic deformation and shearing to form and separate a chip.
Chip interface – It defines the boundary, physical connections, and communication protocols which allow an integrated circuit (IC) to exchange data, power, and signals with other circuits, sub-systems, or external devices.
Chip layout – It is the process of translating abstract circuit logic into precise geometric patterns and layers which form the physical construction of a semi-conductor integrated circuit.
Chip mark – It is the repeating depression caused by a particle adhering to a rotating roll over which the metal has passed.
Chip memory – It is also a semi-conductor memory chip. It is an integrated circuit built from microscopic transistors and capacitors which stores binary digital data (0s and 1s) electronically.
Chip period – It is the duration of a single chip, which is the basic pulse of a pseudo-random noise (PN) or spreading code used in spread-spectrum communications. It is the time interval needed to transmit a single chip within a direct-sequence spread spectrum (DSSS) or code-division multiple access (CDMA) coding sequence.
Chipping – It is removing seams and other surface imperfections in metals manually with a chisel or gouge, or by a continuous machine, before further processing. Similarly, it is also removing excessive metal. Chipping is also a sudden form of tool damage during machining.
Chip process – It refers to the comprehensive manufacturing or fabrication sequence used to build semi-conductor microchips (integrated circuits) from raw silicon.
Chip rate – It is the speed at which individual pulses (called chips) of a spreading code are transmitted in a spread-spectrum communication system, measured in chips per second (cps) or mega-chips per second.
Chip removal – It is a machining manufacturing process where excess material is sheared off a raw workpiece by a harder cutting tool to create a desired shape, size, and surface finish.
Chip-removal methods – These refer to manufacturing processes where a cutting tool shapes a work-piece by removing unwanted material in the form of small pieces called chips. These methods fall under the broader category of subtractive manufacturing.
Chips – These are pieces of material removed from a work-piece by cutting tools or by an abrasive medium.
Chip-scale package – Chip scale packages refer to semi-conductor packaging techniques that allow for batch fabrication at the wafer level, resulting in lower costs and higher yields. This process involves redistributing I/O (input/output) bonding pads and forming bumps using photo-lithographic methods similar to those used in integrated circuit fabrication.
Chip seal – It is a cost-effective road maintenance treatment which sprays a liquid asphalt binder onto an existing pavement surface, covers it with a layer of clean, uniform aggregate chips, and rolls it flat.
Chip select – It is a control line used to activate specific peripheral chips in a master-slave configuration, typically implemented with a GPIO (general-purpose input / output) bus line from the master micro-controller.
Chip serration – It is the formation of saw-tooth or segmented chips with periodically varying thickness during metal machining.
Chip thickness – It refers to the dimension of the layer of metal or material removed by a cutting tool or abrasive grain during a machining process like turning, milling, or grinding.
Chiral chromatography – It is an advanced separation technique to resolve a racemic mixture into its individual, optically active enantiomers (mirror-image isomers).
Chiral compounds – These are molecules which cannot be placed on top of their own mirror image.
Chirp parameter – It quantifies the unwanted or intentional coupling between amplitude modulation (intensity) and frequency/phase modulation in a signal or optical device.
Chirp signal – It is a wave-form where the instantaneous frequency changes continuously over a given time period.
Chi-squared test – It is a test of hypothesis used for testing the association between two qualitative variables or for testing model utility for models estimated with maximum likelihood.
Chi-square test – It is a statistical test used to find out if people’s observed data match their expected data, or if two categorical variables are related. Categorical variables are groups or categories like pass / fail grades.
Chi-square value – It is a statistical test statistic which measures how much a person’s observed count data differs from the expected counts predicted by a null hypothesis.
Chlorargyrite – It is historically referred to as horn silver or cerargyrite. It is the naturally occurring mineral form of silver chloride (AgCl). It is categorized as a high-density halide mineral which serves as an important secondary ore for the industrial extraction of silver. The term ‘horn silver’ derives from its distinct mechanical behaviour under stress, being highly sectile, it can be sliced or carved with a knife much like a piece of animal horn or wax.
Chloride battery – It normally refers to one of three electro-chemical systems where chloride compounds play a main role in the chemical reactions or ion transport. Examples are zinc-chloride cells, lithium-thionyl chloride cells, or emerging chloride-ion rechargeable batteries.
Chloride concentration – It refers to the quantitative measure of chloride ions (Cl-) present in a given aqueous solution, pore network, or structural material matrix (such as concrete or soils), typically expressed in milligrams per litre, parts per million (ppm), or as a percentage of the cement weight.
Chloride content – It refers to the concentration of chloride ions present within a construction material, very frequently concrete, which is a main factor used to assess the risk of steel reinforcement corrosion.
Chloride deposition – It is the accumulation of chloride compounds (such as sea salt aerosols or road de-icing salts) onto the surfaces of materials and structures from the environment.
Chloride diffusivity – It is a measure of a material’s ability, very frequently concrete, to allow the penetration and movement of chloride ions through its pore structure under a concentration gradient. It is a critical parameter used by to predict the service life and durability of reinforced concrete structures exposed to marine environments or deicing salts. High chloride diffusivity indicates that chloride ions can rapidly penetrate the concrete, leading to the premature corrosion of the internal steel reinforcement.
Chloride-induced corrosion – It is the localized deterioration of steel reinforcement inside concrete caused when chloride ions break down the protective passive oxide film on the steel surface.
Chloride ligand – It is a negatively charged chlorine ion (Cl-) which donates a pair of electrons to form a coordinate bond with a central metal atom in a coordination complex.
Chloride penetration – It refers to the depth and rate at which chloride ions (from sources like seawater or deicing salts) infiltrate the pore structure of concrete from the surrounding environment.
Chloride profile – It is a measured graph or distribution showing how chloride ion concentration varies at different depths from the exposed surface of a reinforced concrete structure.
Chloride-rich environments – These are natural or artificial settings where a high concentration of chloride ions (Cl-) is present, posing a severe risk of accelerated material degradation. These ions mainly target infrastructure by destroying the protective passive oxide layer on metals, such as the steel reinforcing bars (rebar) inside concrete or structural stainless steel, initiating a rapid, localized destruction known as chloride-induced corrosion (CIC).
Chlorides – Chlorides refer to compounds containing the chloride ion (Cl-) which act as major contributors to metal corrosion, water salinity, and structural material degradation.
Chlorinated hydrocarbon – It is a generic term given to compounds containing chlorine, carbon and hydrogen. The term can be used to describe organochlorine pesticides such as lindane and DDT (dichloro-diphenyl-trichloroethane), industrial chemicals such as poly-chlorinated biphenyls (PCB), and chlorine waste products such as dioxins and furans. These compounds are persistent in the environment and most bioaccumulates in the food chain. The human and environmental health risks of chlorinated hydrocarbons depend on the compound in question. As a general statement, exposure to chlorinated hydrocarbon has been associated with suppression of the immune system and cancer.
Chlorinated lubricant – It is a lubricant containing a chlorine compound which reacts with a rubbing surface at high temperatures to protect it from sliding damage.
Chlorinated solvent – It is a liquid organic compound of carbon, hydrogen, and chlorine such as methylene chloride, perchloroethylene, 1,1,1-trichloroethane, and trichloroethylene. These solvents are very effective for degreasing with a minimum fire hazard, but their use is heavily regulated because of their classification as ozone-depleting chemicals.
Chlorination – It is roasting ore in contact with chlorine or a chloride salt for producing e chlorides. It is also removing dissolved gases and entrapped oxides by passing chlorine gas through molten metal such as aluminum and magnesium.
Chlorination reaction – It is a chemical process where chlorine atoms are added to a molecule to replace other atoms or groups. It is a type of halogenation where chlorine (Cl2) or a chlorine compound introduces chlorine into an organic or inorganic structure.
Chlorination refining – It is a pyro-metallurgical purification process where chlorine gas or chlorinating agents are introduced into a crude metal melt or concentrate to selectively separate impurities from the primary metal. The process relies on thermodynamic differences between the target metal and its contaminants. When exposed to chlorine at high temperatures, the base metal impurities react preferentially to form volatile or low-density metal chlorides, while the valuable primary metal remains unreacted or easily separable
Chlorinator – It is a device which adds chlorine either in gas or liquid form to water or sewage for killing of bacteria.
Chlorine – It is a halogen element which is isolated as a heavy greenish-yellow diatomic gas of pungent odour. It is used as a bleach, strong oxidizing agent, and disinfectant in water purification. It is an extremely reactive element and has the highest electron affinity.
Chlorine-bearing environment – It refers to an operational setting where materials are exposed to chlorine gas, chloride ions (Cl-), or chlorine-containing compounds. These environments are highly critical in material selection and asset integrity because chlorine and chlorides are aggressively corrosive to several common metals, particularly steels.
Chlorine compound – It is a substance formed when the chemical element chlorine bonds with one or more different elements.
Chlorine dose – It is the quantity of chlorine needed to eliminate pathogens and oxidize reducing agents in water, expressed as the sum of chlorine demand and desired chlorine residual.
Chlorine, dry – Dry chlorine is defined as elemental chlorine (Cl2), in either a gaseous or liquefied state, which contains no more than 150 parts per million (ppm) of water vapour by weight. The Chlorine Institute specifically specifies that in a dry chlorine system, any trace water content is to remain completely dissolved in the solution. If the moisture content exceeds this solubility limit (typically crossing above 150 ppm), it separates to form a distinct, free aqueous liquid phase. This transforms the stream into wet chlorine, which reacts to form highly corrosive hydrochloric (HCl) and hypo-chlorous (HOCl) acids.
Chlorine extraction – It is the removal of phases by formation of a volatile chloride.
Chlorine, wet – Wet chlorine is defined strictly by its moisture content, not its physical phase. It refers to chlorine gas or liquid which contains more than 150 ppm (parts per million) of water vapour. Some systems set this threshold at 100 parts per million. Moisture content is critical to piping, plant design, and asset management since the presence of moisture completely flips the chemical behavior and material compatibility of the system.
Chlorite – It refers to a group of green, sheet-like silicate minerals or a specific chlorine-oxygen chemical ion. In geology, chlorite is a family of about 10 related micaceous minerals (phyllosilicates) which contain no actual chlorine. Chlorite [(ClO2)-] is also a mono-valent inorganic anion and a salt or ester of chlorous acid containing chlorine in a +3-oxidation state. These chemical compounds (such as sodium chlorite) are frequently used as precursors to generate chlorine dioxide for water treatment, disinfecting, and bleaching paper pulp.
Chloroaurate ion – It is very frequently referring to the tetra-chloroaurate(III) ion. It is a polyatomic, negative ion (anion) with the chemical formula [(AuCl4)-]. It is a coordination complex consisting of a central gold atom in a ‘+3’ oxidation state (Au3+) bonded to four chloride ligands (Cl-). The ion has a rigid, square planar molecular geometry. It is typically generated when gold is dissolved in aqua regia (a mixture of nitric acid and hydrochloric acid), forming chloroauric acid (HAuCl4).
Chloroauric acid – It is an orange-yellow inorganic compound which is formed when gold dissolves in aqua regia. Its chemical formula is HAuCl4 (frequently handled as hydrates or in aqueous solution). It has bright yellow-orange crystals, powder, or orange liquid. It is highly soluble in water, ethanol, and ether.
Chloroethene – It is normally known as vinyl chloride. It refers to a highly flammable, colourless gas with a sweet odour. It is a synthetic petro-chemical monomer used almost exclusively to manufacture polyvinyl chloride (PVC) plastics. Since it is a manufactured organic molecule, it lacks the naturally occurring, inorganic, and crystalline structure needed to be classified as a true mineral.
Chloro-fluoro-carbon (CFC) refrigerant – It is a synthetic organic compound containing carbon, chlorine, and fluorine, used historically in engineering and HVAC (heating, ventilation, and air conditioning) systems as a working fluid to transfer heat through phase changes.
Chloro-fluoro-carbons – These are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. Chloro-fluoro-carbons (CFCs) are classified as halocarbons, a class of compounds that contain atoms of carbon and halogen atoms. Whereas Chloro-fluoro-carbons are safe to use in most applications and are inert in the lower atmosphere, they do undergo substantial reaction in the upper atmosphere or stratosphere. Chloro-fluoro-carbons can be a major source of inorganic chlorine in the stratosphere following their photolytic decomposition by ultra-violate (UV) radiation. In addition, some of the released chlorine becomes active in destroying ozone in the stratosphere. Chlorine released from chloro-fluoro-carbons destroys ozone in catalytic reactions where 100,000 molecules of ozone can be destroyed per chlorine atom.
Chloro-phenol – It is a toxic and hazardous chlorinated organic compound where one or more chlorine atoms replace hydrogen on a phenol aromatic ring.
Chlorophyll – It is a green pigment found in all green plants and cyanobacteria (blue-green algae). Chlorophyll is necessary to photosynthesis, a process where plants convert sunlight into chemical energy. Along with phosphorus, chlorophyll is frequently used to estimate productivity in a water body. Concentrations of chlorophyll in a water sample provide a good estimate of the quantity of algae suspended in the water.
Chloroprene rubber – It is a synthetic polymerization product of chloro-butadiene. The mechanical properties are similar to natural rubber. The rubber is considerably better in respect of ozone and oil resistance. Because of chlorine, chloroprene rubber has a high degree of flame resistance. The working temperature range is – 30 deg C to + 80 deg C. Ageing resistance and oil resistance is better with this rubber.
Chlorosilanes – These are reactive, chlorine-containing functional silicon compounds where a silicon atom is bonded to one to four chlorine atoms, with remaining bonds attached to hydrogen or organic groups.
Chloro-tri-fluoro-ethylene – It is a chloro-fluoro-carbon with chemical formula CFCl=CF2. It is commonly used as a refrigerant in cryogenic applications. Chloro-tri-fluoro-ethylene (CTFE) has a carbon-carbon double bond and so can be polymerized to form poly-chloro-tri-fluoro-ethylene. Chloro-tri-fluoro-ethylene as the repeated monomer is a homopolymer and type of high-performance plastic material which belongs to the fluoro-polymers family. It is known for its unique properties consisting of dimensional stability, rigidness with strong chemical resistance, and near-zero moisture absorption.
Chloro-tri-fluoro-ethylene fluids – These are a class of high-performance synthetic lubricants, greases, and heat-transfer oils derived from the polymerization or oligomerization of the chloro-tri-fluoro-ethylene monomer (CFCl=CF2). These fluids are classified as non-flammable, chemically inert fluoro-carbon oils. They are engineered specifically for applications where standard hydrocarbon-based or silicone-based fluids ignite, decompose, or violently react.
Chlorous acid – It is an unstable, pale-yellow inorganic oxo-acid of chlorine with the chemical formula HClO2. It is the least stable of all the oxyacids of chlorine. It can be prepared by treating a suspension of barium chlorite with sulphuric acid followed by removal of the precipitated barium sulphate. Ba(ClO2)2(aq) + H2SO4(aq) = BaSO4(s) + 2HClO2(aq). HClO2 exists only in aqueous solution. It decomposes rapidly in base to give chlorite and chlorate ions and in acid to give chlorine di-oxide and chlorate and chloride ions.
Choice of adhesive – It is the systematic process of selecting the most suitable bonding agent for a specific application based on mechanical, chemical, environmental, and economic requirements.
Choke – It is an inductor used to block higher-frequency alternating currents while passing direct current and lower-frequency alternating currents in a circuit. A choke normally consists of a coil of insulated wire often wound on a magnetic core, although some consist of a doughnut-shaped ferrite bead strung on a wire. The choke’s impedance increases with frequency. Choke is also the restriction in the gating system which controls the flow rate of metal into the mould cavity.
Choked flow – It is a limiting, or maximum, flow condition which either incompressible or compressible fluids can reach in passing through a control valve. It is evidenced by the failure of increasing pressure drop to produce further flow increases. With gas or vapour it occurs when flow velocity reaches sonic value in the vena contracta. With liquid, choked flow indicates fully developed cavitation. The pressure drop over which flow becomes choked is called terminal delta ‘p’.
Choke valve – It is a type of flow control valve which is used for regulating the flow of fluids, such as gases or liquids, in a pipeline. A choke valve is a valve that lifts up and down a solid cylinder (called a ‘plug’ or ‘stem’) which is placed around or inside another cylinder which has holes or slots. The design of a choke valve means fluids flowing through the cage are coming from all sides and that the streams of flow (through the holes or slots) collide with each other at the centre of the cage cylinder, hence dissipating the energy of the fluid through ‘flow impingement’. The main advantage of choke valves is that they can be designed to be totally linear in their flow rate
Choked flow – It is a fluid dynamic limit where the mass flow rate through a constriction cannot increase any further, even if the downstream pressure drops.
Choke line – It is a high-pressure pipe which connects a blowout preventer (BOP) stack to a choke manifold in oil and gas drilling operations.
Cholesky decomposition – It is a decomposition of a Hermitian, positive-definite matrix into the product of a lower triangular matrix and its conjugate transpose, which is useful for efficient numerical solutions, e.g., Monte Carlo simulations.
Cholesky factor – It is the unique lower triangular matrix (L) with positive diagonal entries derived from the Cholesky decomposition of a symmetric (or Hermitian) positive-definite matrix (A).
Cholesky factorization – It is the decomposition of a Hermitian positive definite matrix ‘A’ into the product ‘A = L L to the power T’, where ‘L’ is a lower triangular square matrix with positive diagonal elements. This factorization is used to efficiently solve equations of the form ‘A x = B’ by transforming it into ‘L L to the power T x = B’.
C-hook – It is a device which enables the lifting of a coil through the insertion of the hook into the coil’s inner diameter. A motorized hook rotator powers the rotation of the hook attached to the bottom block of a hoist for additional load control.
Choosing materials – It refers to the process of selecting suitable materials for engineering applications, considering different factors such as physical, metallurgical, mechanical, and chemical properties, as well as performance requirements and cost implications. This decision-making process is complex because of the intricate interactions between multiple selection criteria, frequently aided by multi-criteria decision-making (MCDM) methods.
Chop – It is the metal sheared from a vertical surface of a die forging, which is spread by the die over an adjoining horizontal surface.
Chopped fibre reinforcement – It is a type of reinforcement in composite material where short, discrete fibres are embedded in a matrix material (like a polymer) to improve its properties. These chopped fibres, also known as discontinuous or short fibres, are cut into shorter lengths than continuous fibres, and are used to create isotropic composites where strength is relatively uniform in all directions.
Chopped material – It is a composite reinforcement component made by cutting continuous fibres (such as carbon, glass, or aramid) into short, discrete lengths, typically ranging from 1 millimeter to 50 millimeters, to mix into polymer resins or concrete.
Chopped strand mat – It is a mat formed of strands cut to a short length, randomly distributed, without intentional orientation, and held together by a binder.
Chopped strands – These are short strands cut from continuous filament strands, not held together by any means.
Chopper circuit – It is a high-speed electronic switch which converts a fixed direct current (DC) input voltage into a variable or controlled direct current output voltage. Basically, a chopper is an electronic switch which is used to interrupt one signal under the control of another.
Chopper dies – These are specialized steel-rule components used in cutting dies to chop up scrap material into smaller, manageable pieces during a press stroke. Chopper dies are fabricated from heat-resistant alloys. These dies are used exclusively for hot swaging.
Chopping shear – It is a mechanical cutting device or operation which uses a straight, downward-moving vertical blade (acting like a guillotine or hatchet) against a fixed lower support or anvil to sever stock material without producing chips.
Chord – It is a straight line connecting two points on the circumference of a circle.
Chord diameter – It is the overall diameter of a chord in a tubular joint design, which is a critical parameter for calculating the allowable joint capacity and structural integrity.
Chord length – It is the straight-line distance between the leading edge and the trailing edge of an airfoil, or more broadly, the segment connecting two end-points of a curve or arc. It is also the straight-line distance between two points on the circumference of the circle.
Chord line – It is the transverse dimension of a lifting surface, representing the straight line connecting the leading edge to the trailing edge of a wing or airfoil.
Chord members – These are the top chord and bottom chord in a truss, functioning like the flanges of a beam to resist tensile and compressive forces caused by sectional bending moments. The bottom chords are normally parallel, while the top chords can be parallel or inclined, depending on the design of the truss bridge.
Chord modulus – It is the slope of the chord drawn between any two specific points on a stress-strain curve. It is a term normally used in the polymer field to specify how a single value for the modulus of elasticity is determined from a non-linear load elongation graph from a tensile test.
Chord modulus – It is the slope of the chord drawn between any two specific points on a stress-strain curve.
Chord size – It is the straight-line distance measured from the leading edge to the trailing edge of an airfoil, rotor blade, or turbine profile, or the main straight structural member in a truss or tubular joint framework.
Chord wall – In structural and offshore engineering, the chord wall (or chord wall thickness, denoted as ‘T’) is the thickness of the main continuous pipe or structural hollow section which receives loads from connecting side braces. The ratio of the brace thickness to the chord wall thickness (R = t/T) dictates how the joint transfers stress and resists localized failures like sidewall buckling or face tearing.
Choreography – It is a decentralized coordination pattern where individual services or components interact by reacting independently to shared events rather than following commands from a central controller.
Christoffel equation – It is a homogeneous linear algebraic equation in displacement amplitudes, used to relate the acoustic tensor and wave propagation in bulk composites. It enables the calculation of eigenvalues and eigenvectors which characterize the wave speeds and polarizations in the material.
Christoffel symbols – These are connection coefficients that quantify how the local coordinate basis vectors change from point to point in a curvilinear coordinate system or curved manifold. Christoffel symbols describe the spatial rate of change of the natural basis vectors.
Chaudron diagram – It is also called a Baur–Glassner diagram. It is a phase diagram which shows the stability regions of solid iron oxides in equilibrium with reducing gases like carbon mono-oxide / carbon di-oxide (CO / CO2) or hydrogen / water vapour (H2 / H2O) as a function of temperature and gas composition.
Chromadizing – It is improving paint adhesion on aluminum or aluminum alloys, mainly aircraft skins, by treatment with a solution of chromic acid. It is also called chromidizing or chromatizing. It is not to be confused with chromating or chromizing.
Chroma samples – These refer to the colour information in video signals, which are taken at specific spatial locations relative to luma samples, as demonstrated in different chroma subsampling formats. In these formats, chroma samples are positioned to optimize colour fidelity while minimizing data band-width.
Chroma signal – It is short for chrominance signal. It is the portion of a video signal which carries colour information, specifically hue and saturation, separate from the brightness or luminance (Y) component.
Chromate conversion coatings – These are a type of conversion coating used to improve the corrosion protection of metals and their alloys, characterized by their self-healing properties, ease of application, and high efficiency, although they contain hexavalent chromium, which is highly toxic and environmentally hazardous.
Chromate quenching – It is treating metal in a tank of containing a solution of chromium compounds to produce a conversion coating consisting of trivalent and hexavalent chromium compounds. After galvanizing, the steel item is cooled by quenching in a water bath containing a low concentration of sodium dichromate. The sodium dichromate solution creates a passivation film on the galvanized surface. Chromate passivation sometimes is used on galvanized reinforcement bars to control reactions between zinc and concrete while the concrete cures, particularly the hydrogen evolution which adversely affects bonding. Chromate quenching of galvanized articles prevents the formation of wet storage stain.
Chromate treatment – It is a treatment of metal in a solution of a hexavalent chromium compound to produce a conversion coating consisting of trivalent and hexavalent chromium compounds.
Chromatic aberration – It is a defect in a lens or lens system which results in different focal lengths of the lens for radiation of diverse wavelengths. The dispersive power of a simple positive lens focuses light from the blue end of the spectrum at a shorter distance than light from the red end. An image produced by such a lens shows colour fringes around the border of the image. The difference in the position along the axis for the focal points of light is called longitudinal chromatic aberration. The difference in the magnification because of the variations in position of the principal points for light of different wave-lengths, also a difference in focal length, is known as lateral chromatic aberration.
Chromatic adaptation – It is the computational or systemic process of adjusting colour values to compensate for changes in illumination, allowing digital systems and colour management models to mimic the human eye’s ability to perceive consistent object colours under varying light sources.
Chromatic dispersion – It is the phenomenon where different wave-lengths (colours or frequencies) of a light pulse travel at different group velocities through a transmission medium like an optical fibre, causing the pulse to spread out over distance. Chromatic dispersion is the dependence of the propagation velocity of a wave on its wave-length, resulting in different spectral components traveling at different speeds. This phenomenon can lead to temporal spreading of information, particularly in optical signal transmission.
Chromaticity coordinates – These coordinates refer to the relative proportions of the tristimulus values X, Y, and Z, which can be expressed as x = X / (X + Y + Z) and y = Y / (X + Y + Z). These coordinates provide a simple and comprehensible description of the absolute colour of an object or surface, typically represented in a chromaticity diagram. Chromaticity coordinates define the quality of a colour, specifically its hue and saturation, independent of its brightness or luminance.
Chromaticity diagram – It is a two-dimensional graphical tool used in to map human colour perception based on hue (the colour type like red or green) and saturation (purity or intensity), completely separate from brightness or luminance.
Chromating – It is performing of a chromate treatment. It is also the chromate quenching of a galvanized article.
Chromatogram – It is the visual display of the progress of a separation achieved by chromatography. A chromatogram shows the response of a chromatographic detector as a function of time.
Chromatography – It is a separation method based on the distribution of sample compounds between the stationary phase and a mobile phase.
Chromatography column – It is a cylindrical containment tube packed with a stationary phase material through which a mobile phase (liquid or gas) flows to separate, identify, or purify the components of a chemical mixture.
Chromatography technique – It is a method for analyzing and separating the components of a mixture by dissolving it in a mobile phase that moves through a stationary phase, allowing the different components to migrate at varying speeds. This technique is utilized in both qualitative and quantitative analysis to understand and purify mixtures.
Chrome brick – It is a refractory brick, which can be burned or unburned, manufactured predominantly or entirely of refractory-grade chrome ore, and having a chromium oxide (Cr2O3) content of 30 % or higher.
Chromel – It is a nickel-chromium alloy typically composed of 90 % nickel and 10 % chromium. It features high electrical resistance, strong resistance to heat and oxidation, and is widely used as the positive wire in Type K and Type E thermocouples to measure high temperatures.
Chromel-alumel – It refers to the alloy combination used as the conductor pair in standard Type-K thermocouples for measuring high temperatures. Chromel is an alloy made of around 90 % nickel and 10 % chromium. It acts as the positive conductor leg. Alumel is a magnetic alloy made of about 95 % nickel, 2 % manganese, 2 % aluminum, and 1 % silicon. It acts as the negative conductor leg.
Chromel-alumel thermocouple – It is normally designated as a Type-K thermocouple. It is a popular temperature measurement device made from two joined, dissimilar metal alloy wires which generate a predictable voltage based on the Seebeck effect.
Chrome alloy – It is a metallic mixture where chromium serves as a principal or important alloying element combined with iron, nickel, cobalt, or molybdenum to improve strength, hardness, and corrosion resistance.
Chrome-magnesia brick – It is a refractory brick, which can be burned or unburned, manufactured predominantly of a mixture of refractory-grade chrome ore and refractory-grade magnesia in which the refractory-grade chrome ore predominates by weight. The refractory-grade magnesia can be either seawater magnesia, dead-burned magnesite, fused magnesia, or a combination of these materials.
Chrome-magnesite refractories – These refractories normally contain 15 % to 35 % Cr2O3 and 42 % to 50 % MgO. They are produced from sintered magnesia and chrome ore.
Chrome ore – It is a naturally occurring mineral aggregate, mainly composed of chromite (FeCr2O4), which serves as the sole commercial source for extracting chromium metal and producing ferro-chrome alloys.
Chrome ore, refractory-grade – It is a refractory ore consisting essentially of chrome-bearing spinel with only minor quantities of accessory minerals and having physical and chemical properties suitable for making refractory products.
Chrome pickle – It consists of producing a chromate conversion coating on magnesium for temporary protection or for a paint base. It is also the solution which produces the conversion coating.
Chrome plating – It is an electroplating process which deposits a controlled layer of chromium onto a metal or prepared plastic substrate to improve surface hardness, wear resistance, low friction, and corrosion protection.
Chrome-spinel – It is a term which is normally used for a chromium-rich spinel or less commonly hercynite but also for chromite and magnesio-chromite, and perhaps any chromium-bearing spinel-group mineral, e.g. chromium-bearing magnetite, ferro-chromite etc.
Chrome steel – It is an alloy steel which contains chromium as its main added element to improve hardness, strength, and wear resistance.
Chromia-alumina brick – It is a refractory brick, which can be burned or unburned, manufactured predominantly of a mixture of chromic oxide (Cr2O3) and a high-alumina raw material, with the chromic oxide content being 50 % or higher and with alumina (Al2O3) predominating by weight among the other constituent oxides.
Chromia scale – It is a dense, continuous, and protective layer of chromium oxide (Cr2O3) which forms naturally on the surface of chromium-containing alloys when exposed to oxygen at high temperatures. Normally found on stainless steels and nickel-based or cobalt-based superalloys, this scale acts as a solid-state diffusion barrier. It drastically slows down subsequent high-temperature oxidation and environmental corrosion by separating the underlying metal from aggressive ambient gases.
Chromic acid – It is a strong, corrosive, and toxic chemical compound (typically H2CrO4 or a mixture formed from chromium trioxide and sulphuric acid) featuring hexavalent chromium (+6 oxidation state), widely used for electroplating, metal finishing, and anodizing.
Chromic acid solution – It is a highly corrosive, strong oxidizing liquid, typically formed by dissolving chromium tri-oxide (CrO3) in water or mixing sulphuric acid with a di-chromate solution, containing hexavalent chromium [Cr(VI)].
Chromic oxide brick – It is a refractory brick, which can be burned or unburned, manufactured predominantly of chromic oxide (Cr2O3) and having a Cr2O3 content of 90 % or higher (can also be called chromia brick).
Chromic steels – These are a class of alloy steels where iron is combined with chromium content typically ranging from 1 % to 30 % to considerably boost hardness, tensile strength, and resistance to corrosion and oxidation.
Chrominance – It refers to the colour information in a video signal, which is typically conveyed through colour difference signals. It is less sensitive to resolution loss than luminance, allowing for more efficient bandwidth utilization by subsampling the chrominance channels in various formats.
Chrominance component – It is the signal part carrying an image or video’s colour data (hue and saturation), kept separate from the brightness data (luminance).
Chromite – It is the main ore mineral of chromium. It is a crystalline mineral composed primarily of iron (II) oxide and chromium (III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr2O4). Substitution of the element aluminum can also occur, leading to hercynite (FeAl2O4). Chromite today is mined particularly to make stainless steel through the production of ferro-chrome (Fe-Cr), which is an iron-chromium ferro-alloy.
Chromite content – It refers to the precise measurement, categorization, and specification of chromium ore (FeCr2O4) within a geological deposit or processed concentrate. Defining of the chromite content determines the economic viability of a deposit and dictates how the ore is to be processed.
Chromite deposits – These are concentrated natural accumulations of chromite, an iron chromium oxide mineral with the chemical formula FeCr2O4, which serve as the main commercial source for extracting chromium.
Chromite-magnesia refractory – It is also called magnesia-chromite refractory. It is a high-temperature ceramic material made from a blend of magnesium oxide (magnesia, MgO) and chrome ore (chromite), designed to line industrial furnaces. It normally contains higher quantities of magnesia (MgO 50 % to 80%) combined with chromite providing chromium oxide (Cr2O3 8 % to 35 %). It functions as a basic refractory, i.e., it resists basic (alkaline) slags. It withstands extreme temperatures frequently exceeding 2,000 deg C without melting or deforming. The addition of chromite helps the material handle rapid temperature changes better than pure magnesia alone. It resists corrosion from both basic and acidic liquid slags, making it chemically stable in harsh environments.
Chromite-magnesite refractory – It is a high-performance, chemically basic refractory material composed of a blended mixture of chrome ore (chromite) and magnesia (magnesite / magnesium oxide). It is defined by its ability to retain structural integrity, resist mechanical wear, and withstand severe chemical attack by both acidic and basic slags at extreme temperatures typically exceeding 1,500 deg C to 1,700 deg C.
Chromite ore – It is a natural oxide mineral, specifically iron chromium oxide (FeCr2O4) belonging to the spinel group. It serves as the sole commercially viable source for extracting chromium. It belongs to the spinel group, forming a solid solution where magnesium and aluminum frequently substitute for iron and chromium.
Chromite refractory – It is the refractory composed predominantly of chromite and containing higher than or equal to 30 % by mass of chromium sesquioxide and less than 30 % by mass of magnesium oxide.
Chromium (Cr) – It is also known as chrome. is a chemical element; its atomic number is 24. It is the first element in group 6. It is a chemical element. Chromium is a chemical element. It is a steely-grey, lustrous, hard, and brittle transition metal. It is valued for its high corrosion resistance and hardness. Chromium is normally added to steel to increase corrosion resistance, wear resistance, and oxidation resistance, to increase hardenability, or to improve high temperature strength.
Chromium alloyed steels – These are materials made by combining iron and carbon with chromium as a main alloying element to considerably improve hardness, tensile strength, and resistance to corrosion.
Chromium buffing compound – It is a buffing compound consisting of fine unfused alumina. Originally, it has been developed to colour buff chromium-plated parts which had been stained or frosted in the electroplating process.
Chromium carbide – It is an extremely hard, corrosion-resistant ceramic and refractory compound made of chromium and carbon (Cr3C2, Cr7C3, and Cr23C6) used to harden metal surfaces and control grain growth.
Chromium-carbon (Cr23C6) precipitate – It is also called chromium carbide. It is a chemical compound which forms as a solid precipitate within the micro-structure of certain metal alloys, most notably stainless steels and nickel-based superalloys, when they are exposed to high temperatures. The precipitation of Cr23C6 is a critical phenomenon since it directly alters a metal’s mechanical strength and corrosion resistance. Chromium-carbon precipitate forms a complex cubic crystal structure with 92 metal atoms and 24 carbon atoms per unit cell. It typically precipitates when the alloy is heated within the range of 500 deg C to 850 deg C. Precipitation normally occurs preferentially along grain boundaries (the borders between individual crystal grains in the metal), where atomic diffusion is faster.
Chromium content – It refers to the quantity of chromium (Cr) present in stainless steels, which is necessary for providing basic corrosion resistance. Normally, higher chromium content results in improved corrosion resistance and improved oxidation resistance at high temperatures.
Chromium depletion – It is a localized reduction in chromium concentration, normally dropping below roughly 12 %, near grain boundaries or metal surfaces in stainless steels and nickel-based alloys.
Chromium hot-work die steels – These are a group of specialized alloy tool steels engineered to retain strength, hardness, and structural integrity under severe thermal cycling and mechanical stress at high temperatures (480 deg C to 760 deg C).
Chromium hot work steel – It is a group of alloy tool steels designed to retain strength, hardness, and resistance to thermal shock at high temperatures between 480 deg C to 760 deg C.
Chromium hot-work tool steels – These are specialized alloy steels designed to withstand high pressure, severe thermal cycling, and abrasion at high temperatures.
Chromium-manganese steels – These are alloy steels which use chromium for hardness and corrosion resistance, and manganese in place of or alongside nickel to stabilize an austenitic structure.
Chromium-molybdenum steels – These steels are heat resistant steels. They contain 0.5 % chromium to 9 % chromium and 0.5 % molybdenum to 1 % molybdenum. The carbon content is normally below 0.2 %. Chromium provides improved oxidation and corrosion resistance while the molybdenum increases strength at high temperatures. These steels are normally produced in the normalized and tempered, quenched and tempered or annealed conditions. These steels are extensively used in the oil and gas industries and in fossil fuel and nuclear power plants.
Chromium-molybdenum-nickel steels – These are high-performance alloy steels which combine iron with chromium, molybdenum, and nickel to achieve superior strength, toughness, and corrosion resistance.
Chromium-molybdenum-vanadium (CrMoV) steel – It is a high-performance low-alloy steel engineered to maintain high strength, resistance to deformation, and structural stability under extreme heat and pressure.
Chromium-nickel cementation steels – These are normally known as case-hardening steels. These steels are low-carbon alloy steels specifically designed to undergo surface-hardening treatments (such as carburizing) to produce a high-hardness, wear-resistant outer shell (case) while maintaining a highly ductile, impact-resistant inner core.
Chromium-nickel steel – It is an alloy steel containing iron, carbon, chromium, and nickel as its main components, known for offering high strength and corrosion resistance. While several stainless steels fall under this category, nickel-chromium steels also include structural and engineering alloys designed for specialized mechanical performance.
Chromium nitrides – These are a class of advanced interstitial ceramic compounds formed by the chemical reaction of chromium and nitrogen. They are mainly used as hard, wear-resistant, and corrosion-resistant thin-film coatings applied through physical vapour deposition (PVD), or generated directly on the surface of alloy steels through industrial nitriding heat treatments. Structurally, they are interstitial compounds where small nitrogen atoms occupy the spaces (octahedral holes) within the larger chromium metal crystal lattice. Because of this atomic configuration, they do not behave as typical ionic chemical salts. Chromium nitrides mainly exist in two distinct chemical phases, frequently appearing together in tailored industrial surfaces namely chromium mono0nitride (CrN), and di-chromium nitride (Cr2N).
Chromium mono-nitride (CrN) – It possesses a cubic, rock-salt (NaCl) crystal structure. It is highly valued for its superior high-temperature oxidation resistance, excellent toughness, and low coefficient of friction.
Chromium oxide – It refers to a chemical compound represented as Cr2O3, which is an important component of chromite, an iron chromium oxide mineral. It is characterized by its high chromium content and is used in several applications, including metallurgical processes and the production of pigments.
Chromium plating – It is also known as chrome plating. It is a process which applies a thin layer of chromium to the surface of a metal object. This is typically done through electroplating, where the object is submerged in a solution containing chromium and a current is applied to deposit the chromium onto the surface.
Chromium removal – It is the systematic process of extracting or reducing toxic chromium compounds from industrial waste-water, ground-water, or soil to safely comply with environmental discharge regulations. The challenge mainly stems from the two most common forms of chromium found in water namely tri-valent chromium [Cr(III)] and hexavalent chromium [Cr(VI)].
Chromium-silicon-spring – It is a high-strength mechanical device made from alloy steel wire containing chromium and silicon, built to handle heavy shock loads, high stress, and temperatures up to 245 deg C.
Chromium-silicon spring-wire – It is a high-tensile alloy steel wire treated with chromium and silicon to handle high stress, shock loads, and heat up to 245 deg C).
Chromium-silicon steel – It is frequently referred to as chrome-silicon steel. It is a high-performance alloy steel engineered mainly for manufacturing components which need exceptional fatigue resistance, extreme strength-to-weight ratios, and high dimensional stability under cyclic loads. Its main metallurgical signature is a highly coordinated synergy between chromium and silicon. This prevents the material from ‘setting’ or permanently sagging under high operational stress and moderately high temperature.
Chromium steels – These are alloy steels containing iron and chromium as a main alloying element, typically ranging from 1 % chromium to over 20 % chromium, designed to improve hardness, tensile strength, wear resistance, and durability against corrosion.
Chromium system – It defines an alloy system characterized by a mixture of metals where chromium is a fundamental component.
Chromizing – It is a surface treatment at high temperature, normally carried out in pack, vapour, or salt baths, in which an alloy is formed by the inward diffusion of chromium into the base metal.
Chromophore – It is the specific region of a molecule responsible for absorbing light and producing colour or undergoing electronic transitions.
Chronic – It is something which occurs over a long period of time, either continuously or intermittently. It is used to describe ongoing exposures and effects which has developed only after a long exposure.
Chronic exposure – It is a continuous or repeated exposure to a hazardous substance over a long period of time.
Chronic problem – It is a problem because of the inherent variation in a process being more than permitted by the specifications.
Chrono-amperometry – It is a method where a fixed electrode potential is set against a reference electrode while monitoring the current flow between the working and counter electrodes.
Chrono-potentiometry – It is a technique which involves controlling the current flow while monitoring the changes in the working electrode potential.
Chua’s circuit – It is an electronic circuit which demonstrates chaotic behaviour and is characterized by its simple implementation, capable of generating multiple attractors. It serves as a foundational example in chaos research and can be extended to analyze other autonomous systems described by differential equations. It is the simplest electronic circuit which serves as a universal paradigm for non-linear dynamics
Chuck – It is a device for holding work or tools on a machine so that the part can be held or rotated during machining or grinding.
Chucking lug – It is a lug or boss added to a forging so that on-centre machining and forming can be performed with one setup or checking. This lug is finally machined or cut away.
Churn flow – It is a chaotic, highly turbulent gas-liquid two-phase flow regime in vertical or near-vertical pipes where an unstable liquid film oscillates up and down while being disrupted by large, irregular gas slugs.
Chu sequence – It is a complex-valued mathematical signal with constant amplitude and ideal cyclic autocorrelation, widely used in telecommunication engineering for synchronization and channel estimation.
Chute – It is a passage or channel designed to guide material flow from one conveyor to another or a specific destination. It necessitates periodic inspection for blockages and wear. It is also an opening, normally constructed of steel and equipped with a gate, through which material is drawn from a storage bin. It is also a part of the bell less charging equipment for charging charge material in the blast furnace. The chute is normally rotated while charging and its angle to the vertical can be changed.
Chute lining – It is highly abrasion resistant elastomeric lining in a chute to protect the metal chute from abrasion wear.
Chvorinov foundry technology principle – It states that the solidification time of a casting is proportional to the square of the volume-to-surface ratio, highlighting the dynamic coupling between thermo-mechanical quantities during casting solidification and cooling.
Chvorinov’s rule – It is a simplified approach to determining solidification time. It states that the total solidification time of a molten metal casting is proportional to the square of its volume-to-surface-area ratio. Under identical conditions, parts with larger volumes and smaller cooling surface areas freeze slower than thin parts with large surface areas.
Cigar cooler – It is also called copper jacket or copper cooler. It is a cylindrical cooling element which is used to improve heat transfer and protect the furnace shell. Cigar coolers are installed between other cooling elements, such as plate coolers, where more intensive cooling is needed or when there is insufficient spacing between those elements.
Cinching – Cinching is scratch which is for rolled products, it is a sharp indentation in the surface normally caused by a machine or during handling, while for extrusions, it is a synonym for handling mark.
Cinder notch – It is also known as slag notch. All the blast furnaces do not have this notch. The cinder notch is used for tapping of slag from the furnace.
Cine-fluorography – It is a technique for generating moving images using X-rays, which is part of the broader category of fluoroscopic imaging. It allows for the visualization of dynamic activities within the body, capturing the motion of anatomical structures.
Cinnabar – It is a vermilion-coloured ore mineral of mercury.
CIP – It is the acronym for cold isostatic pressing, which is a forming technique in which high fluid pressure is applied to a powder (metal or ceramic) part at ambient temperature. Water or oil is used as the pressure medium.
Cipher-text – It is the result of applying an encryption algorithm to plain-text, transforming it into a format which is not easily readable without the appropriate decryption key.
Circle – It is a shape consisting of all points in a plane which are at a given distance from a given point, the centre. The distance between any point of the circle and the centre is called the radius. The length of a line segment connecting two points on the circle and passing through the centre is called the diameter. It is also a circular blank fabricated from plate, sheet, or foil.
Circle brick – It is a brick, the two large faces of which are parts of concentric cylinders.
Circle cutter tool – It is a specialized mechanical or manual device designed to produce a round opening or circular profile through rotational cutting motion. The term normally refers to two major categories namely hole-cutting/extraction tools and advanced milling tools.
Circle grid – It is a regular pattern of circles, frequently 2.5 mm in diameter, marked on a sheet metal blank.
Circle-grid analysis – It is the analysis of deformed circles for determining the severity with which a sheet metal blank has been deformed.
Circle grid pattern – It is a series of uniformly sized, perfectly round circles etched onto sheet metal to measure material deformation and strain during forming processes.
Circle grids – Several types of circle grid patterns have been used, such as square arrays of contacting or closely spaced non-contacting circles and arrays of overlapping circles. The contacting and overlapping circles provide improved coverage but are more difficult to measure manually. With small, closely spaced circles, it is possible to determine strain gradients accurately, provided the circles are not too small for accurate measurement. Circles with 2.5 millimeters diameters have been found to be a good size. Both open and solid circles have been used successfully, and automatic systems have been developed for measuring both types. The circle grids can be applied to the blanks by a printing or photographic technique or by electro-chemical etching. Printed and photographically applied circles are easily damaged and tend to rub off in areas contacted by the dies. This has led to general acceptance of etched circles.
Circle grid strain analysis – It is a test method used to measure surface deformation and strain levels in sheet metal after it undergoes forming processes like stamping or drawing.
Circle grinding – It is either cylindrical grinding or internal grinding which are the preferred terms.
Circle of concern – It encapsulates all the issues, events, and challenges that we care about but over which we have no direct control. These can range from global phenomena like climate change and economic fluctuations to more personal matters such as other people’s opinions or past events. Essentially, the circle of concern is vast and can frequently lead to feelings of helplessness and stress when one dwells excessively on these uncontrollable factors.
Circle of control – It is a concept which refers to the things which people have the power to change or influence. It is a way of thinking about their life and responsibilities which helps the people to focus on what is within their control and let go of things which they cannot control.
Circle of influence – It suggests that people are influenced by a range of factors, including their family, friends, colleagues, and wider social networks. These influences can be positive or negative, and can impact an individual’s beliefs, values, and behaviors in different ways.
Circle shear – It is a shearing machine with two rotary disk cutters mounted on parallel shafts driven in unison and equipped with an attachment for cutting circles where the desired piece of material is inside the circle. It cannot be used to cut circles where the desired material is outside the circle.
Circofer process – The Circofer process is similar to the Circored process. It reduces fine ores with coal in a circulating fluidized bed, in which the reducing gas used is produced by gasification of coal. Circofer process utilizes a combination of circulating and stationary fluidized beds. The fine ores are preheated in a two-stage integrated preheating unit before being admitted to the first reduction stage. The first reduction stage is a circulating fluidized bed reactor, with an integrated heat generator in which the necessary energy is supplied to the system by partial oxidation of coal with oxygen. This partial coal combustion integrated with the circulating fluidized bed system not only produces the heat needed for the process but, specifically, supplies the char required as reducing carbon and anti-sticking agent. With this arrangement it is possible to conduct the circulating fluidized bed pre-reduction at high temperatures of a 950 deg C without prompting a sticking of the fine ores. Iron ore fines and recycled char, from the magnetic separation of the product prior to briquetting, are pre-heated to around 800 deg C in a two-stage circulating fluidized bed system utilizing the off-gas sensible heat from the process. The pre-heated materials are charged into the circulating fluidized bed reactor through a gasifier. Coal is charged directly into the gasifier which operates at a temperature of around 1,000 deg C, where it is oxidized partially with the help of injected oxygen to generate the heat required for the process. The solids and gases enter the circulating fluidized bed, where the iron oxide is reduced at a temperature of around 950 deg C to a metallization degree of around 70 %. Solids from the circulating fluidized bed are transferred to the fluidized bed reactor for the final reduction step to a metallization of around 93 %. The metallized product, ash and excess char are discharged from the fluidized bed reactor, cooled to around 730 deg C and subjected to magnetic separation. The metallized product is hot briquetted at around 680 deg C. The non-magnetic char is recycled back to the process.
Circored process – The process is a natural gas-based process for the production of direct reduced iron from iron ore fines. It is a two-stage fluidized bed process. The first reduction stage is a circulating fluidized bed, the second reduction stage a bubbling fluidized bed reactor. For the heating up of the fine grained direct reduced iron product to briquetting temperature, a flash heater is used. The hydrogen-based Circored process produces highly metalized direct reduced iron or hot briquetted iron for direct feed into electric arc furnace for the steelmaking. The process reduces energy consumption and emissions and offers a sustainable solution for the steelmaking. The special features of the process are (i) direct use of iron ore fines without prior agglomeration, such as pelletizing or sintering, and (ii) operation with pure hydrogen as reducing gas enables reduction with very low carbon di-oxide emission values, and allows the application of low reduction temperatures minimizing sticking tendencies. Hydrogen is produced by means of natural gas reforming, but hydrogen from sources other than a steam reformer, e.g. from water electrolysis, can also be used.
Circuit – In filament winding, it is one complete traverse of a winding band from one arbitrary point along the winding path to another point on a plane through the starting point and perpendicular to the axis. It is also a complete circular path which an electric current can flow around.
Circuit breaker – It is an electrical safety device designed to protect an electrical circuit from damage caused by current in excess of that which the equipment can safely carry (overcurrent). Its basic function is to interrupt current flow to protect equipment and to prevent fire. Unlike a fuse, which operates once and then is to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.
Circuit conditions – These refer to the operational states of an electrical circuit during which a mechanical switching device, like a circuit-breaker, can carry and break currents under both normal and specified abnormal circumstances, such as short-circuiting.
Circuit core – It is the domain within a mobile core network consisting of nodes and functions which provide traditional dedicated-channel, circuit-switched services (such as voice calls and legacy data) over cellular networks like GSM (global system for mobile communications) and WCDMA (wide-band code division multiple access.
Circuit debugger – It is in-circuit debugger (ICD) which is a hardware tool used to test, programme, and troubleshoot software running directly on physical micro-controllers or embedded hardware.
Circuit debugging – It is the systematic process of analyzing an electrical or electronic circuit, identifying faults, and correcting errors to ensure it functions according to its design specification.
Circuit design – It is the systematic process of planning, selecting, and inter-connecting electronic components to create a functional circuit which transforms inputs into specific outputs while meeting operational, power, and environmental constraints. Circuit design bridges raw electrical concepts and real-world physical utility by optimizing for factors like cost, reliability, size, and thermal stability.
Circuit designer – Circuit designer is a professional who creates, tests, and optimizes electronic circuits to perform specific functions within larger electronic systems.
Circuit diagram – It is a graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic diagram shows the components and interconnections of the circuit using standardized symbolic representations.
Circuit efficiency – It is the ratio of useful power output to the total electrical power input, expressed as a percentage. Efficiency (%) = (useful output power / total input power) x 100.
Circuit element – It is the basic mathematical model of a two-terminal electrical device defined entirely by its voltage-current relationship. It is a basic building block of an electrical circuit, represented mathematically by its voltage-current relationship. Circuit elements are divided into two main groups based on how they handle energy. These are active elements, and passive elements.
Circuit emulator – It is frequently called an in-circuit emulator (ICE). It is a powerful hardware debugging tool which temporarily replaces or connects directly to the central processing unit (CPU) or micro-controller of a target electronic system to test, run, and monitor embedded software and hardware.
Circuit fault – It is an abnormal condition in an electrical fault system which causes current to flow outside its intended path or disrupts the normal flow of electricity.
Circuit frequency – It is the number of complete cycles an alternating current (AC) voltage or current wave-form completes in one second. It is measured in hertz (Hz), where 1 hertz equals one complete cycle per second. Direct current (DC) has a frequency of 0 hertz since the current flows in a single constant direction, whereas alternating current continuously switches back and forth.
Circuit ground – It is a stable reference point in an electrical circuit which is necessary for reducing electro-magnetic interference and ensuring proper operation, particularly in low frequency precision analogue circuits where accurate ground paths are critical to prevent common impedance coupling.
Circuit impedance – It is the total opposition which an electrical circuit presents to the flow of an alternating current (AC), combining both resistance and reactance into a single complex quantity measured in ohms.
Circuit model – It is a simplified mathematical or graphical representation of an electrical system which uses idealized components like resistors, capacitors, and inductors connected by nodes to analyze behaviour and performance.
Circuit parameters – These parameters refer to the values of the circuit elements which characterize the behaviour of a circuit model, such as resistance and capacitance, which are influenced by the state of charge (SOC) in the context of battery modelling.
Circuit performance – It is the measure of how well an electronic or electrical circuit functions as per its intended design specifications and operational goals.
Circuit potential – It refers to the electric potential (or voltage) at a specific node or point in an electrical circuit relative to a reference point, such as ground, or the natural voltage difference (open circuit potential) between terminals when no external current flows.
Circuit power factor – It is the ratio of real working power to total apparent power in an alternating current (AC) circuit.
Circuit programming – It is the process of loading software, firmware, or logic configurations into a programmable integrated circuit (IC), such as a microcontroller, FPGA (field programmable gate array), or memory chip, to define and control its operational behaviour.
Circuit realization – It is the process of converting an abstract mathematical model, logic expression, or functional specification into a physical or programmable electronic circuit using actual components.
Circuit simulation – It is a computational process which uses mathematical models and software algorithms to predict, analyze, and verify the electrical behaviour of an electronic circuit before it is physically built or manufactured.
Circuit test – It is an evaluation method used to check the physical integrity, electrical parameters, performance, or safety of a circuit or electrical machine without fully loading or powering it under normal operating conditions.
Circuit testing – It is the process of applying controlled electrical signals to a circuit or printed circuit board assembly (PCBA) to verify its physical integrity, connection accuracy, and component values.
Circuit theory – It is a foundational branch of electrical engineering which studies the design, analysis, and behaviour of interconnected electrical networks and components.
Circuit variables – These are the fundamental, measurable physical quantities, specifically voltage and current, used to describe the behaviour of energy, charges, and signals in an electric circuit.
Circulant matrix – It is a square matrix where each row is shifted to the right by one position compared to the row above it. It is an M × M matrix whose entries satisfy ‘C(i, j) = r[(i − j) mod (N)]’, where ‘r’ is the first row of the matrix, indicating that each row or column can be got by a circulant shift of the previous one.
Circular antenna – It normally refers to a circularly polarized (CP) antenna which radiates electro-magnetic waves with an electric field rotating in a circle, or a circular patch / loop antenna built with a circular physical geometry.
Circular aperture – It is a round opening or stop in an optical, antenna, or acoustic system which controls the passage of waves and defines the boundaries of a beam.
Circular arc – It is a smooth, continuous segment of a circle’s circumference connecting two distinct points, defined by a specific radius and a central angle.
Circular arc elongation test – It is standardly referred to as the ‘hole expansion test’ (International Organization for Standardization standard ISO 16630). It measures the edge-stretchability and localized circular elongation limits of a material. It is a destructive test used to evaluate the edge ductility and cracking resistance of sheet metal when a circular boundary or profile is forced to elongate.
Circular beam – It is a structural member which follows a curved or circular path from an overhead or plan view.
Circular buffer – It is a fixed-size data structure that treats a single continuous block of memory as if it were connected end-to-end in a circle.
Circular carbon economy – Iti s an economic framework which manages carbon emissions through a closed-loop system based on four pillars known as the 4 Rs which are reduce, reuse, recycle, and remove.
Circular channel – It is defined as a type of canal designed to convey water, characterized by its circular geometry, where the design involves determining suitable values for properties such as circular radius and water depth to optimize flow conveyance and minimize construction costs.
Circular columns – These are structural elements with a circular cross-section which are evaluated for energy dissipation and reinforcement ratios, where parameters such as diameter and reinforcement area are critical for calculating yield deformation and energy dissipation quantities.
Circular convolution – It is a mathematical operation on two finite-length sequences where the indices wrap around using modular arithmetic as if the signals are periodic.
Circular cutter – It is a rotating tool with a round blade or edge used to cut round holes, grooves, or cylindrical shapes out of solid materials.
Circular cross section – It is the 2D shape people see when they slice straight through a 3-dimensional cylinder, cone, or sphere perpendicular to its long axis, revealing a perfect circle.
Circular cylinder – It is a three-dimensional shape with two parallel, identical circular bases connected by a curved side.
Circular cylinder wake – It is the disturbed, frequently turbulent region of fluid flow which forms directly downstream behind a circular cylinder as fluid moves past it.
Circular cylindrical shell – It is a hollow, curved structural element with a circular cross-section where the wall thickness is very small compared to the radius and length.
Circular diaphragm – It is a round, thin structural membrane or plate which flexes symmetrically when exposed to differential pressure.
Circular dichroism – It is an optical spectroscopy. It is a chiroptical method which measures the different absorption of left-handed and right-handed circularly polarized radiation by chiral molecules, particularly in the ultra-violet or visible range, facilitating the analysis of their electronic transitions and secondary structures.
Circular drainage area – It is the theoretical circular zone surrounding a wellbore from which fluids or hydrocarbons flow inward toward the well.
Circular duct – It is a round, tubular passage used to transport air, gases, or other fluids through an internal flow system with maximum aerodynamic efficiency.
Circular economy – It is an economic system designed to eliminate waste, keep products and materials in use for as long as possible, and regenerate natural systems. Unlike the traditional linear economy, which follows a ‘take-make-waste’ pattern of extracting resources, making products, and throwing them away, the circular economy creates a closed-loop system. Circular economy keeps materials and products in circulation for as long as possible. It refers to an economy which uses a systems-focused approach and involves industrial processes and economic activities which are restorative or regenerative by design, enables resources used in such processes and activities to maintain their highest value for as long as possible, and aims for the elimination of waste through the superior design of materials, products, and systems (including operational models). It is a change to the model in which resources are mined, made into products, and then become waste. A circular economy reduces material use, redesigns materials and products to be less resource intensive, and recaptures ‘waste’, or material which has been previously considered to be a waste, as a resource which can serve as feedstock to manufacture new materials and products.
Circular economy concept – It is an economic system which replaces the traditional ‘end-of-life’ model with strategies for reducing, reusing, and recycling materials throughout production, distribution, and consumption processes, aiming to achieve sustainable development through environmental quality, economic prosperity, and social equity.
Circular economy initiative – It is a strategic programme designed to eliminate waste and pollution by keeping products and materials in continuous use.
Circular field – It is the magnetic field which (i) surrounds a non-magnetic conductor of electricity, (ii) is completely contained within a magnetic conductor of electricity, or (iii) both exists within and surrounds a magnetic conductor. It is normally applied to the magnetic field within any magnetic conductor resulting from a current being passed through the part or through a section of the part.
Circular frequency – It is the rate of oscillation measured in radians per unit time, represented by the equation ‘w = 2 pi ν’, where ‘v’ is the optical frequency. It is related to the energy of a photon through the equation ‘E = h w’ with ‘h’ being the reduced Planck’s constant.
Circular geometry – It is the application of circular shapes, curves, and mathematical properties of circles to design and analyze structures, mechanical parts, and fluid systems.
Circular grid pattern-based surface strain measurement system – It is a tool used to quantify plastic deformation and material flow on sheet metal surfaces during stamping or forming processes.
Circular hole – It is a specific type of geometric feature characterized by a constant radius, where the equations applicable to elliptical holes also hold true when the semi-minor and semi-major axes are equal. The stress concentration factor for a circular hole in a two-dimensional infinite solid under uniaxial tension is equal to 3, and it varies based on both geometry and loading conditions.
Circular hole-drilling method – It is a semi-destructive testing technique used to measure residual stresses in materials by analyzing the local strain changes that occur when a small, shallow circular hole is drilled into the surface.
Circular hollow sections – These sections refer to structural members characterized by a hollow circular cross-section, normally used in engineering applications such as tower construction. Their design involves checks on dimensions, stresses, and slenderness ratios to ensure structural integrity.
Circularity – It means the quality of being shaped like a circle, moving in a cycle, or keeping materials in continuous use to eliminate waste. It is also a two-dimensional form tolerance which controls how closely any given cross-section of a cylindrical, spherical, or conical feature adheres to a true circle.
Circular model – It is an economic framework which emphasizes the recovery and reuse of materials, components, and products, aiming to eliminate waste and promote sustainability through the interconnections of design, production, consumption, and disposal. This model contrasts with the traditional linear economic model by addressing environmental unsustainability and pollution.
Circular motion – It is a movement of an object along the circumference of a circle or rotation along a circular arc. It can be uniform, with a constant rate of rotation and constant tangential speed, or non-uniform with a changing rate of rotation. The rotation around a fixed axis of a three-dimensional body involves the circular motion of its parts. The equations of motion describe the movement of the centre of mass of a body, which remains at a constant distance from the axis of rotation. In circular motion, the distance between the body and a fixed point on its surface remains the same, i.e., the body is assumed rigid.
Circular nozzle – It is a fluid dynamics device with a axisymmetric, round opening designed to control, direct, or accelerate the flow of a fluid (liquid or gas) as it exits a system. It converts the fluid’s pressure energy into kinetic energy, resulting in a higher velocity stream. In this nozzle, the internal flow passage and the exit orifice are completely round. It features axial symmetry, meaning the fluid behaviour is uniform around the central axis. It typically produces a concentrated, symmetrical jet of fluid.
Circular orbit – It is a closed trajectory with an eccentricity of zero (e = 0), where an object travels around a central body at a constant radius and constant speed.
Circular orifice – It is a precision-machined round opening in a wall, plate, or pipe through which a fluid (liquid or gas) flows to restrict, direct, or measure the rate of flow.
Circular path – It is a plane trajectory where a moving point or object stays at a constant distance, or radius (R), from a central point while its position changes by an angle.
Circular pipe – It is a long, hollow cylindrical conduit with a round cross-section used to convey fluids (liquids and gases) or provide structural support.
Circular pitch – It is the distance from a point on one gear tooth to the corresponding point on the next tooth, measured along the arc of the pitch circle.
Circular plate – It is a flat, round structural component defined by its radius and thickness, designed to carry transverse loads (forces perpendicular to its surface) while supported or clamped at its edges.
Circular polarization – It is a state of electro-magnetic wave propagation where the electric field vector maintains a constant magnitude while continuously rotating in a circle perpendicular to the direction of travel.
Circular strip – It is the region bounded by two concentric circles of different radii. It refers to a continuous, flat piece of material (like metal, plastic, or rubber) formed into a loop or stamped out as a ring, frequently used for gaskets, seals, or structural bands.
Circular surface – In advanced mathematics (differential geometry), it is a surface generated by moving a circle through three-dimensional space along a base curve. In basic geometry, it frequently refers to a flat circular area or the curved lateral boundary of a circular solid like a cylinder or cone.
Circular symmetry – It is a property where an object or function remains unchanged (invariant) when rotated by any arbitrary angle around a central point or axis.
Circular tank – It is a cylindrical container with a round cross-section built to hold, treat, or process liquids like water, waste-water, and chemicals.
Circular trajectory – It is a curved path of travel or movement which follows the circumference of a circle at a fixed or changing distance from a central point.
Circular tube – It is a hollow, cylindrical conduit with a round cross-section defined by an inner radius, outer radius, and uniform wall thickness. It is the one of the simplest tube geometry which is widely used for different heat transfer applications.
Circular velocity – It is the velocity possessed by an object while undergoing uniform circular motion. Uniform circular motion is a two-dimensional motion in which an object moves in a circular motion at a constant speed while the velocity changes at each location due to the changing direction of the velocity vector.
Circular weld – It is a continuous or closed-loop weld joint following a circular path, normally used to attach round components like shafts, tubes, or nozzles to plates and cylindrical vessels. It follows a 360-degree perimeter around a circular cross-section. It is frequently executed as a circular fillet weld design to resist torsion or as a circumferential groove weld in pressure vessels.
Circulating drilling fluid – It is a liquid or gas (normally called drilling mud) pumped continuously down through the hollow drill string, out the drill bit, and back up the annulus (the space between the drill pipe and the borehole wall) to the surface during drilling operations.
Circulating fluid – It is a working liquid or gas which is continuously pumped or driven through a closed or open loop to transfer heat, cool equipment, or transport materials.
Circulating fluidized bed (CFB) boiler – It is a type of boiler which burns solid fuels in a fluidized bed, where fuel and bed material (like sand or limestone) are suspended in a stream of air or gas. This suspension creates a fluid-like behavior, allowing for efficient mixing and heat transfer. Circulating fluidized bed boilers are known for their fuel flexibility, ability to handle different fuels, and for their potential to reduce emissions.
Circulating fluidized bed combustion – It is an advanced thermal engineering technology where solid fuels are burned in a suspended, fluid-like mixture of hot inert particles and air, with continuous recycling of unburnt solids.
Circulating fluidized beds – These beds are popular for large-scale combustion operations, and they are also gaining attention for gasification of carbonaceous feedstocks. Circulating fluidized beds utilize the entire height of tall vessels for gas–solids contacting, with no distinct interface between bed and freeboard. The corresponding flow regime is usually fast fluidization for combustion and gasification of solid fuels. Operating conditions, riser geometry, hydro-dynanics, heat transfer, solids feed and particle recirculation all have considerable influence on the operation and effectiveness of the system.
Circulating fluidized bed scrubber – It is a type of scrubber which circulates boiler ash and lime between a scrubber and fabric filter. Flue gas enters the circulating fluidized bed scrubber (with or without ash) at the bottom of the up-flow vessel, flowing upward through a venturi section that accelerates the gas flow rate, causing turbulent flow. The turbulator wall surface of the vessel causes highly turbulent mixing of the flue gas, solids, and water for 4 to 6 seconds to achieve a high capture efficiency of the vapor phase acid gases and metals contained within the flue gas. The gas and solids mixture then leaves the top of the scrubber.
Circulating glycol – It is a specialized water-glycol fluid mixture pumped through a closed-loop system to transfer thermal energy, prevent freezing, and inhibit corrosion.
Circulating load – It is the over-sized chunks of ore returned to the head of a closed grinding circuit before going on to the next stage of treatment.
Circulating pressure – it is the total fluid pressure generated by mud pumps to circulate drilling fluid (mud) through the entire wellbore system.
Circulating pump – It is a specialized mechanical device, typically an inline centrifugal pump, designed to move fluids continuously through a closed-loop piping system. Unlike standard water pumps which lift water from a deep source or push it over great vertical elevations, a circulating pump only needs to generate enough pressure (or ‘head’) to overcome the internal friction of the closed pipe network.
Circulating valve – It is a downhole mechanical device used to open a fluid path between the work string, drill string, or production tubing and the surrounding wellbore annulus.
Circulating water – It is water supplied continuously through a piping and pump network to remove waste heat from industrial equipment like steam condensers, heat exchangers, or process plants.
Circulating water channel – It is an experimental testing facility which holds a model stationary while pumping water past it to simulate relative motion.
Circulation – It is the movement of water and steam within a steam generating unit.
Circulation control – It refers to the regulation and optimization of the movement, stirring, and mixing of molten metal inside a reactor, ladle, or furnace. Maintenance of specific circulation patterns is necessary to achieve a uniform chemical composition, ensure even temperature distribution, and eliminate impurities.
Circulation distribution – It refers to the spatial variation and pattern of fluid motion (such as liquid metal, slag, gas, or leaching solutions) within a reactor, furnace, or separation unit. Since metallurgical extraction processes rely heavily on heat transfer, mass transfer, and chemical kinetics, how a fluid circulates and distributes itself across a vessel directly dictates the efficiency, purity, and speed of the reaction.
Circulation fan – It is a mechanical device designed to move and distribute air continuously within a space without using air ducts. It is a heavy-duty industrial fan integrated into heat-treatment furnaces to forcibly move heated air, gases, or protective atmospheres within the chamber. Its main purpose is to maximize temperature uniformity and accelerate heat transfer to the metallic workload.
Circulation flow rate – It the volume or mass of a fluid moving through a closed loop, system, or cross-section per unit of time. It is the speed and volume at which a molten metal melt moves through a processing vessel (such as in a degassing or refining unit) per unit of time. It measures the quantity or mass of liquid metal moving through a designated loop or mixing zone per second or minute.
Circulation pump – It is a mechanical device which moves fluids, typically water, in a continuous loop within a closed system to maintain consistent flow and temperature. Unlike standard transfer pumps which lift or move fluids to a different vessel, a circulation pump stays submerged or connected inline to keep the liquid bath in a constant, controlled loop.
Circulation rate – It refers to the mass or volume flow rate at which material (such as slurry, molten metal, or gas) is continuously recycled through a specific process loop relative to the feed rate. It is very frequently used in mineral processing (flotation and grinding circuits) and pyro-metallurgy (vacuum degassing and smelting) to optimize efficiency, control residence time, and improve chemical reactions.
Circulation ratio – It is the ratio of water entering a circuit to the steam generated by the water which passes that circuit in a unit of time.
Circulation round a curve – It is defined as the line integral of the velocity vector around a simple closed curve. It measures the total ‘quantity’ of the velocity field circulating around the curve.
Circulation sub – It is a device used to open a circulation path above the bottom hole assembly (BHA) or to restore circulation in the event of a blockage, utilizing mechanisms such as a burst disk, a shear-out ball drop, or a combination of both.
Circulation time – It is the total duration needed for a fluid, or substance to complete a specific circuit, flow between two designated points, or cycle through a system.
Circulation zone – It is a spatial region within a metal or granular material where coherent, vortex-like rotational motion occurs among localized particles or atoms. Circulation zone also refers to a internal thermal or chemical loop where specific volatile elements evaporate in the high-temperature bottom of a furnace, rise with the gas, cool down, condense onto the solid raw materials, and are carried back down to the bottom.
Circulator – It is a pipe or tube to pass steam or water between upper boiler drums normally located where the heat absorption is low. It is also used to apply to tubes connecting headers of horizontal water tube boilers with drums.
Circulatory flow – It refers to the continuous, looping movement of molten metal or slurry within a metallurgical vessel. This movement forms closed-loop flow patterns driven by forces like gas injection (e.g., argon stirring), electromagnetic stirring, or mechanical impellers. Circulatory flow is important for maintaining chemical and thermal uniformity during metal processing.
Circumferential – It describes a thing which follows, surrounds, or acts along the outer boundary, perimeter, or circular path of a round object like a pipe, cylinder, or gear.
Circumferential crack – It is a fracture or structural defect which runs around the outer or inner perimeter (circumference) of a cylindrical structure, such as a pipeline, tube, or pressure vessel, in a direction perpendicular to its longitudinal axis.
Circumferential direction – It is the path or orientation which follows the outer perimeter, curving around a circular or cylindrical object perpendicular to its central, longitudinal axis.
Circumferential displacement – It is the movement or translation of a point along a circular arc, perimeter, or tangential direction of a cylindrical or rotating object.
Circumferential distance – It is the linear arc length measured all the way around the outer or inner perimeter of a circular or cylindrical object. It is the path or boundary length encircling a cross-section, frequently used to map positions on cylindrical structures like pipes, pressure vessels, or rotating shafts.
Circumferential grain flow – It is an internal structure where the microscopic grains of a metal ring or cylinder stretch and align in a continuous circular direction around the perimeter.
Circumferential hoop stress – It is a normal tensile or compressive stress which acts tangentially along the circumference of a cylindrical or spherical object, such as a pipe or pressure vessel, caused by internal or external pressure.
Circumferential mode – It defines a specific spatial variation pattern or wave shape of a system’s physical property (such as vibration, pressure, or acoustic waves) repeating around the perimeter or circumference of a circular, cylindrical, or rotating structure.
Circumferential order – It refers to an integer parameter, denoted as ‘n’, which specifies the number of complete wave cycles or harmonic variations around the perimeter (circumference) of a cylindrical, circular, or rotational structure.
Circumferential ply – It is a layer of reinforcing material (such as fibre-reinforced composite tape or filament winding) oriented at around a 90-degree angle relative to the longitudinal axis of a cylindrical or tubular structure.
Circumferential stress – It is also called hoop stress. It is the normal stress acting tangentially around the circumference of a cylindrical tube or pipe wall, caused by internal or external pressure.
Circumferential surface crack – It is a fracture or discontinuity which initiates at the external or internal boundary of a cylindrical or tubular metal component and propagates along a path perpendicular to the longitudinal axis (around the circumference).
Circumferential velocity – It is the linear speed of a point on a rotating object moving along a circular path, directed tangent to the circumference.
Circumferential wave – It is an acoustic or elastic wave which travels around the circumference (the curved, outer or inner perimeter) of a cylindrical or ring-shaped structure, rather than along its length.
Circumferential weld – It is also called a girth weld. It is a closed-loop joint made by welding around the outer perimeter of a cylindrical or spherical structure. It joins pipe sections, attaches end caps (heads) to pressure vessels, or seals round components to ensure structural continuity and leak-proof containment. It mainly resists longitudinal stresses (axial tension or compression) running parallel to the axis of the cylinder or pipe.
Circumferential winding – In filament- wound reinforced plastics, it is a winding with the filaments essentially perpendicular to the axis (90-degree or level winding).
Circumscribing circle – It is a circle which just contains the cross section of an extrusion, normally designated by its diameter.
cis – It is a prefix for polymers denoting a type of molecular structure. For some unsaturated carbon chain atoms within a repeat unit, a side atom or group can be situated on one side of the double bond or directly opposite at a 180-degree rotation position. In a cis structure, two such side groups within the same repeat unit reside on the same side (e.g., cis-isoprene).
Cistern – It is a tank for storing water or other liquids, normally placed above the ground.
Citric acid – It is a weak organic tri-carboxylic acid with the chemical formula C6H8O7 which is produced on an industrial scale mainly through large-scale microbial fermentation. Citric acid is defined by its molecular structure, mass production methods, and functional properties. Its IUPAC (International Union of Pure and Applied Chemistry) name is 2-hydroxypropane-1,2,3-tricarboxylic acid. Its structure contains three carboxyl (-COOH) groups, making it a tribasic which can release three protons in solution, and one hydroxyl (-OH) group. It is white, odourless, crystalline powder or clear crystals at room temperature.
Civil construction – It is the practical branch of civil engineering which on building, improving, and maintaining public and private infrastructure involving earth, water, and transport. While general civil engineering centers on the planning, analysis, and blueprints of systems, civil construction brings those designs to life in the physical world. It involves transforming raw land and materials into functional networks.
Civil construction industry – It is a major sector of civil engineering focused on the design, creation, and maintenance of public and private physical infrastructure, particularly projects involving water, earth, and transport.
Civil design – It is the process of creating plans, technical drawings, and specifications for infrastructure like roads, bridges, and water systems.
Civil drawing – It is used for specifying the shape and position of the civil foundation. It typically includes the information such as (i) setting out dimensions for the concrete structure on site, (ii) plans, sections and elevations showing layout, dimensions and levels of all concrete members, (iii) location of all holes, chases, pockets, fixings and other items affecting the concreting work, (iv) notes on specifications, finishes and all cross-references affecting the construction. The drawing provides the detailer with the layout and sectional information required to specify the length, shape and number of each type of reinforcing bar. Reinforcement drawing is part of civil drawing. It fully describes and locates all reinforcements in relation to the finished surface of the concrete and to any holes or fixings. The civil drawing is also a type of technical drawing which shows information about grading, landscaping, or other site details.
Civil engineering – Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewage systems, pipelines, structural components of buildings, and railways.
Civil engineering structure – it is an organized arrangement of connected load-bearing components designed to safely support loads and resist external forces like gravity, wind, and earthquakes.
Civil engineers – Civil engineers are professionals who design and construct infrastructure such as buildings, transportation systems, and facilities for water resource management, using knowledge from physical sciences, mathematics, and project management to ensure public health and safety.
Clad aluminum – It is a composite material made by bonding a thin outer layer of one metal (like pure aluminum, copper, or nickel) onto a core of an aluminum alloy or another material to combine the best traits of both.
Clad brazing sheet – It is a metal sheet on which one or both sides are clad with brazing filler metal.
Cladding – It is a layer of material, usually metallic, that is mechanically or metallurgically bonded to a substrate. Cladding can be bonded to the substrate by any of several processes, such as roll-cladding and explosive forming. Cladding also means a relatively thick layer (1 millimeter) of material applied by surfacing for the purpose of improved corrosion resistance or other properties.
Cladding interface – It is the critical boundary zone or contact surface where an outer protective layer (the cladding) meets and bonds with an inner core, substrate, or adjacent structural assembly.
Cladding layer – It is a protective or functional outer skin permanently bonded or attached to a core substrate to shield it from environmental or chemical damage.
Cladding material – It is the material of the outer layer applied to a substrate to provide specific properties such as wear resistance, corrosion resistance, weather resistance, thermal insulation, and an improved aesthetic. For example, clad materials are used when the corrosion resistance of carbon steel is inadequate even with the addition of corrosion inhibitors, or when economic considerations or mechanical strength do not warrant replacing carbon steel with a corrosion-resistant alloy (CRA). Under these conditions, the most practical, economical solution is to coat (clad) corrosion-resistant alloy material onto carbon steel.
Cladding mode -It is an optical path where light propagates mainly through the outer cladding layer of a fibre wave-guide rather than staying confined to the central core.
Cladding process – It is the process of bonding or melting a layer of one material over a base substrate to provide a protective, corrosion-resistant, or decorative exterior. Common methods are roll bonding, explosive bonding, extrusion, and advanced techniques like laser cladding (or directed energy deposition), which uses a laser to melt metal powder or wire onto a component.
Cladding systems – These systems refer to the exterior finish layer installed to cover walls and support structures, serving functions such as improving appearance, optimizing thermal and environmental performance, and protecting against outdoor elements. These systems can include different materials like stucco, masonry veneer, marble, ceramic tile, and exterior insulation and finish systems (EIFS).
Clad material – It is a material that has a thin layer of aluminum or aluminum alloy metallurgically bonded to it normally by rolling, extruding or drawing. Most frequently it is used to provide a more corrosion resistant surface or to facilitate anodizing.
Clad metal – It is a composite metal containing two or more layers which have been bonded together. The bonding can have been accomplished by co-rolling, co-extrusion, welding, diffusion bonding, casting, heavy chemical deposition, or heavy electroplating.
Clad sheet – It is a metal sheet on which one or both sides are clad.
Clad track – It is defined as a single deposition of a laser beam which creates a layer of material on a substrate during the laser cladding process, characterized by specific geometrical features such as clad height, width, and area, achieved through controlled parameters like laser power and scanning speed.
Clad tube – It is a hollow cylindrical metal pipe which has a protective outer or inner layer metallurgically bonded to a stronger base metal.
Claim – It is a formal demand or assertion by one party for extra money, more time, or other compensation under the terms of a contract.
Clamp – It is a fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure.
Clamp connector – It is developed as the high pressure, low weight, leak-free alternative to the standard flange. The clamp connector does not rely on complex bolting to maintain seal integrity, but offers the strength of a welded joint. This design is the preferred solution where space, weight and joint integrity are critical. There are also some proprietary designs.
Clamp coupling – A typical clamp coupling essentially consists of two half cylinders which are placed over the ends of the shafts to be coupled and are held together by through bolt.
Clamped edges – These refer to boundary conditions of a beam where the displacement and slope at the edge are restricted, resulting in a rigidly fixed section that maintains a horizontal tangent at that point.
Clamped end – It is a boundary condition where a structural member, beam, or plate is held rigidly so that it cannot move or rotate in any direction.
Clamped plate – It is a flat structural element whose edges are completely fixed and rigidly restrained, preventing both transverse displacement (up-and-down movement) and rotation (slopes) at the boundaries.
Clamping – It the application of controlled mechanical, hydraulic, or pneumatic force to securely hold, support, and position a work-piece or component.
Clamping force – It is the force which is used to hold a work-piece or object securely in place, frequently by using clamps or other fastening devices. It is a crucial aspect of several processes, including machining, welding, injection moulding, and more. Essentially, it is the force which ensures things stay put and do not move or separate under stress. In case of conveyor system, it depends on the friction factor of clamp and belt surfaces and on the (downhill) force.
Clamping pressure – In injection moulding and transfer moulding, it is the pressure which is applied to the mould to keep it closed in opposition to the fluid pressure of the compressed moulding material.
Clamping voltage – It is the maximum voltage a surge protection device or voltage-limiting component allows to pass through to connected equipment during a high-voltage transient event.
Clamp-off – It is indentation on a casting surface because of the displacement of sand in the mould.
Clamshell – It denotes anything resembling the bivalve shell of a clam.
Clamshell gate – It is a pivotal gate integrated into a conveyor system, designed for controlled opening and closing. Regular inspections are necessary to ensure proper functionality and prevent potential material spillage.
Clamshell marks – These are macroscopic progression marks on a fatigue fracture or stress-corrosion cracking surface which indicate successive positions of the advancing crack front. The classic appearance is of irregular elliptical or semielliptical rings, radiating outward from one or more origins. These marks (also known as beach marks or arrest marks) are typically found on service fractures where the part is loaded randomly, intermittently, or with periodic variations in mean stress or alternating stress.
Clapeyron equation – It is a fundamental relationship which describes the behaviour of phase transitions in a pure substance, relating changes in pressure and temperature at equilibrium between phases. It is derived from the Gibbs-Duhem equation and incorporates the concepts of enthalpy and entropy.
Clarification – It is the removal of suspended matter from raw water supplies to make water more suitable for industrial or domestic requirements. The process involves the coagulation, flocculation, and sedimentation of particulates.
Clarification process – It is a separation process used to remove suspended solid particles or low-concentration impurities from a liquid or gas.
Clarified water – It is the water which has passed through a sedimentation or clarification process to remove suspended solids, particulates, and floating debris.
Clarifier – It is a settling tank designed to remove solid particles and suspended solids from liquids, typically in wastewater treatment. It works by allowing the liquid to flow through the tank, where solids settle to the bottom (as sludge) or float to the surface (as scum), which are then removed. The clarified liquid is then collected and used for further treatment or discharged. Clarifiers rely on the principle of gravity settling, where heavier solids sink to the bottom of the tank under the influence of gravity.
Clarifier sludge – It is the concentrated suspended matter which is removed from water during the clarification process in treatment plants, typically resulting from the use of coagulants to improve solid separation.
Clark electrode – It is a device used to measure oxygen tension in gas mixtures, consisting of a platinum cathode and a silver anode in an electrolyte solution, with a potential difference applied between them. The flow of current generated in response to oxygen levels allows for the determination of oxygen tension.
Clark-type oxygen probe – It is a polarographic sensor used to measure the concentration or partial pressure of dissolved oxygen in a liquid or gas sample.
CLAS – It is a casting process in which metal fills the mould through the drag by application of a vacuum. It also refers to chemical looping air separation (CLAS) which is an advanced oxygen-production technology utilized in energy and metallurgical oxy-combustion plants. It is a cyclical chemical process using metal oxides (frequently copper-based) to separate oxygen from air without energy-intensive cryogenic distillation.
Class – As per UNFC (United Nations Framework Classification for Resources) classification, a Class is the primary level of resource classification resulting from the combination of a category from each of the three criteria (axes). A Class is uniquely defined by selecting from each of the three criteria a particular combination of a Category or a Sub-category (or groups of Categories/Sub-categories). Since the codes are always quoted in the same sequence (i.e., E, F, G), the letters can be dropped and just the numbers retained. The numerical code defining a Class is then identical in all languages using Hindu-Arabic numerals. In statistical analysis class consists of observations grouped according to convenient divisions of the variate range, normally to simplify subsequent analysis (the upper and lower limits of a class are called class boundaries, the interval between them the class interval, and the frequency falling into the class is the class frequency).
Class 4 sections – These are cross sections with plate component slenderness so large that local buckling occurs prior to reaching the elastic moment resistance
Class distribution – It refers to the relative frequency of different categories within a dataset, where an uneven distribution can lead to biased classification results. In cases where one class is considerably more prevalent than others, classification methods can favour predictions toward the larger class, potentially resulting in all objects being classified as belonging to it.
Classical beam – It is also known as a Euler-Bernoulli beam. It is a long, slender structural element designed to carry loads that act perpendicular to its length.
Classical beam theory – It is a theoretical framework used for analyzing the behaviour of beams, where shear deformation and rotary inertia are negligible, particularly applicable for determining lower frequency vibrations in structures. It uses relationships between strain, curvature, and resultant forces to derive the equations of motion for beams.
Classical boundary conditions – These conditions define the specific physical or mathematical constraints applied at the edges of a system, such as clamped, simply supported, or free ends in structural mechanics.
Classical control – It uses feedback control to regulate the behaviour of dynamical systems, involving concepts like stability, performance, and robustness for the analysis and design of feedback controllers.
Classical controlled rolling – It is a thermo-mechanical processing method which combines precise temperature management and plastic deformation to refine a metal’s grain structure and improve its mechanical properties.
Classical control system – It is a method which uses feedback loops and transform-domain mathematics to regulate single-input, single-output (SISO) dynamical systems.
Classical control theory – It is a branch of engineering which uses feedback loops and frequency domain analysis to design and regulate single-input, single-output dynamical systems.
Classical elasticity theory – It is a branch of continuum mechanics that studies linear elastic solids, which are deformable materials that recover their original configuration after the removal of applied forces. It provides a model for analyzing the mechanical behaviour of different structural materials, including metals, concrete, wood, and rocks, under normal loading conditions.
Classical error correction – It is the method of detecting and fixing corrupted data in communication channels and storage systems by adding redundant bits.
Classical field – It is a theoretical framework which assigns a continuous physical quantity, such as a scalar, vector, or tensor, to every point in space and time.
Classical flutter – It is a self-excited, dynamic aeroelastic instability where the interaction of aerodynamic, elastic, and inertial forces causes two or more structural modes (typically bending and torsion) to couple and oscillate with growing amplitudes.
Classical information theory – It is a mathematical framework which quantifies how information is measured, compressed, and reliably transmitted over communication channels in the presence of noise and uncertainty. It addresses fundamental engineering problems in telecommunications, data storage, and signal processing.
Classical interpolation – It is the method of finding an approximation polynomial which passes through a set of specified data points so one can estimate unknown values in between them.
Classical lamination theory – It is a standard analytical method used in engineering mechanics to predict the stiffness, deformation, and stress behavior of thin, fibre-reinforced composite laminates under applied loads and moments. It simplifies a complex three-dimensional problem into an easily solvable two-dimensional framework.
Classical method – It refers to an analytical approach which uses exact mathematical equations, closed-form solutions, and differential calculus based on foundational, established principles rather than discrete approximations.
Classical nucleation theory – It is a foundational model used to quantify the kinetics of how a new thermodynamic phase (like a solid crystal, liquid droplet, or gas bubble) emerges from a metastable parent phase.
Classical plasticity theory – It is a branch of solid mechanics which defines and predicts the permanent, irreversible deformation of materials (like ductile metals) when subjected to loads which exceed their elastic limit.
Classical plate theory – It is a frame-work for analyzing the displacement and strain components of a plate, incorporating parameters such as bending rigidity, Young’s modulus, and Poisson’s ratio to describe the mechanical behaviour of thin plates under different loading conditions.
Classical realm – It is the macro-scale domain where physical phenomena are accurately predicted by deterministic laws, continuous variables, and classical mechanics rather than quantum mechanics.
Classical shell theory – It is a foundational two-dimensional structural mechanics framework used to analyze thin, curved structures by reducing three-dimensional elasticity problems down to the shell’s middle surface based on the Kirchhoff–Love hypothesis.
Classical source – It is a source of light which emits states represented by a positive and bounded quasi-probability distribution in the Glauber-Sudarshan representation, such as discharge lamps or lasers.
Classical surface – It treats a manufactured or natural solid boundary as a random statistical profile defined by a probability density function of surface heights and a second-order auto-correlation.
Classical test theory – It is a psychometric framework stating that any observed measurement or test score (X) is the sum of an underlying true value (T) and a random measurement error (E). ‘observed score (X) = true score (t) + error (E)’. These foundational concepts are used to evaluate instrument precision and data reliability.
Classical theory – It refers to foundational, pre-20th-century analytical frameworks which describe macroscopic physical systems using deterministic laws, linear approximations, and established conservation principles without accounting for modern quantum or relativistic complexities.
Classical thin plate theory – It is a theoretical frame-work which describes the behaviour of thin, homogeneous plates under load, where it assumes that transverse normal stresses are negligible compared to bending stresses and that straight fibres remain straight and perpendicular to the reference surface during deformation.
Classical tomography – It is an early X-ray imaging technique which produces a sharp image of a single internal plane of an object while blurring out structures in all other planes.
Classification – Classification is defined as a method of separating mixtures of mineral particles into two or more products according to their settling velocities in water, in air or in other fluids. Classification is performed on the basis of the velocity with which the material particles fall through a fluid medium generally water or air. Classification of minerals follows Stokes’ law of sedimentation. It is also separation of a metal powder into fractions as per particle size.
Classification accuracy – It is the ratio of correct predictions made by a model to the total number of input samples or predictions. Classification accuracy measures how frequently a classification algorithm or recognition system correctly labels data. For binary classification (two classes), it is calculated using the confusion matrix values. ‘accuracy = [true positives (TP) + true negatives (TN)] / [true positives (TP) + true negatives (TN) + false positives (FP) + false negatives (FN)]’, where true positives (TP) are correctly predicted positive cases, true negatives (TN) are correctly predicted negative cases, false positives (FP) are incorrectly predicted positive cases, and false negatives (FN) are incorrectly predicted negative cases.
Classification algorithms – These are methods which determine the category to which a set of data belongs, such as faulty, fault type, or healthy categories. The selection of a classification algorithm involves choosing the one which provides optimal performance while considering computational time constraints.
Classification error – It is the difference between a measured value and the true value. It refers to the misclassification which occurs when data points belonging to different classes overlap in a probability distribution, leading to incorrect assignment of entities to classes based on the highest probability measure.
Classification methods – These are fundamental techniques hat find mathematical models capable of recognizing the membership of objects to their respective classes based on a set of measurements. These methods can be probabilistic or distance-based, and they include different traditional and emerging approaches such as discriminant analysis and artificial neural networks.
Classification network – It is an artificial neural network designed to categorize input data into predefined classes or categories based on features learned during training.
Classification neural network – It is an artificial intelligence model designed to sort input data into predefined categories or classes.
Classification number – In product lifecycle management (PLM) and manufacturing engineering, a classification number refers to a prefix or standardized block of digits inside an engineering part number used to categorize components. Rather than assigning random numbers, organizations use standard codes (such as those outlined by the international ECLASS classification system which is an international, cross-industry standard for the uniform classification and description of B2B products and services) to quickly identify what a part is. For example, a classification prefix of 01 can denote all fasteners, while 02 can denote electrical components.
Classification of colour – It is the systematic arrangement of colours based on visually or instrumentally assessed parameters, facilitating communication, comparison, and analysis of aesthetic relations among colours.
Classification performance – It refers to the evaluation of a measurement system’s ability to accurately predict class membership in a multi-class problem, typically assessed using metrics such as true positive rate (sensitivity) and positive predictive value (precision). These metrics quantify how well a classifier can identify the correct classes while minimizing false positives and false negatives.
Classification process – It is the systematic procedure of organizing data, objects, or observations into predefined groups or categories based on specific shared characteristics or attributes.
Classification rule – It is a specific procedure, condition, or ‘if-then’ statement used to predict or determine which category or class a data point, object, or piece of work belongs to be based on its attributes.
Classification scheme – It is a structured, hierarchical method used to systematically categorize data, components, materials, or systems based on shared characteristics, context, or behaviour.
Classification system – It is an organized method for grouping items, data, or ideas into specific categories based on shared traits or rules.
Classification table – In logistic regression, it is a table showing the cross-tabulation of a subject’s actual status as case or control with the model’s prediction of whether that subject is a case or control.
Classification tasks – These refer to predictive modelling tasks where the target variable is categorical, aiming to determine the class or category into which new data is going to fall. These tasks can be categorized into binary, multi-class, multi-label, or unbalanced classification based on the nature of the target variable.
Classifiers – In classifiers, use is made of the different rates of movement of particles of different sizes and densities suspended in a fluid and differentially affected by imposed forces such as gravity and centrifugal fields, by making suitable arrangements to collect the different fractions as they move to different regions. Based on their separation principles, classifiers are classified into two major types. They are (i) wet classifiers, and (ii) dry classifiers. Wet classification with hydro-cyclones using separation by centrifugal force typically covers the size range of 10 micrometers to 100 micrometers while wet classification with spiral classifiers using separation by gravity typically covers the size range of 100 micrometers to 1,000 micrometers. Dry classification using separation by centrifugal force typically covers the range of 5 micrometers to 150 micrometers.
Class scatter matrix – It is a mathematical representation used in linear discriminant analysis (LDA) to measure and quantify the spread or dispersion of data points. It breaks down into two main types (within-class scatter matrix and between- class scatter matrix ) to help supervised learning algorithms separate different classes effectively.
Class scenario – It is a specific, ordered sequence of interactions between external actors (or object classes) and a system to achieve a particular functional goal.
Class separability – It is a metric which measures how well different data groups or classes can be distinguished from one another based on their feature values.
Class variance – It is a statistical term which measures how much the average values (means) of different groups or classes vary from the overall average of a dataset.
Clathrate – It is a cage-like crystalline structure formed by a host material which physically traps guest molecules inside its cavities without forming chemical bonds. Clathrates are structures in which small gas molecules are enclosed in a framework of hydrogen-bonded water molecules. These are normally found in marine sediments and characterized by their ability to exist under high gas pressure and low temperatures.
Clathrate hydrates – These are ice-like crystalline inclusion compounds where a host lattice of hydrogen-bonded water molecules physically traps small guest gas molecules (such as methane, carbon di-oxide, or ethane) inside polyhedral cages.
Clathrate structure – It is a crystalline inclusion compound where a network of host molecules forms cage-like cavities which physically trap small guest molecules without chemical bonding. These are very frequently clathrate hydrates (or gas hydrates), where hydrogen-bonded water molecules encase gases like methane under low temperatures and high pressures.
Claude cycle – It is a modified thermodynamic refrigeration and liquefaction process which uses both work-extraction expansion and throttling to achieve extremely low cryogenic temperatures. It is a cryogenic thermodynamic cycle which combines an isentropic (work-producing) expansion through a turbine or piston engine with an isenthalpic (Joule-Thomson) expansion through a valve.
Clausius-Clapeyron equation – It is a fundamental thermodynamic formula which describes the relationship between pressure and temperature during a phase change, such as liquid-to-gas vapourization or solid-to-gas sublimation. It allows you to calculate how a substance’s vapour pressure changes when the temperature changes.
Clausius-Clapeyron equation – It is a thermodynamic relationship which defines the-rate-of-change of saturation pressure with respect to temperature along a phase-transition boundary (such as liquid-vapour or solid-liquid).
Clausius-Clapeyron relationship – It is the differential equation relating the pressure of a substance (normally water vapour) to temperature in a system in which two phases of the substance (water) are in equilibrium.
Clausius-Duhem inequality – It is the local, continuum-mechanics formulation of the second law of thermodynamics, used to ensure that material models and constitutive equations do not violate thermodynamic principles.
Clausius inequality – It states that the cyclic integral of heat transfer divided by absolute temperature is always less than or equal to zero for any thermodynamic cycle.
Clausius statement – Clausius statement of the second law of thermodynamics specifies that heat cannot spontaneously flow from a cooler body to a warmer body without external work input.
Claus plant– It is an industrial facility which converts poisonous hydrogen sulphide (H2S) gas into safe, valuable elemental sulphur.
Claus process – It is the standard industrial method used to convert toxic hydrogen sulphide (H2S) gas into harmless, marketable elemental sulphur.
Clay – It is a fine-grained natural soil or mineral material with particles typically smaller than 2 micro-meters to 4 micro-meters, characterized by high plasticity when wet and significant strength when dry. It is a natural, earthy, fine-grain material which develops plasticity when mixed with a limited quantity of water. Foundry clays, which consist essentially of hydrous silicates of alumina, are used in moulds and cores. Clays play a crucial role in soil stability, industrial applications, and even in the ceramics industry, where they are moulded and fired to create various products.
Clay alteration – It refers to the chemical or physical transformation of clay minerals when exposed to changes in temperature, pressure, moisture, or chemically active fluids.
Clay bonded sand – It is the moulding sand which uses clay as binder and is made of foundry sand, clay, water and additives (such as sea-coal, etc.) mixed in a certain proportion. Clay is a normally used binder in sand mould casting production, which can be divided into kaolin or bentonite. Clay bonded sand can be divided into wet sand and dry sand as per different conditions of use, in which wet sand is also called green sand.
Clay bricks – These are traditional rectangular building units manufactured by moulding, drying, and firing a homogeneous mixture of clay, silica, alumina, and fluxes at high temperatures (around 900 deg C to 1,000 deg C).
Clay brick-work – It is a construction method which uses fired or unfired clay units bonded together with mortar to build stable structures like walls and foundations. Clay brick-work is an assembly of clay bricks and mortar designed to act as a cohesive structural element.
Clay-coating method – It refers to the industrial application of a fine clay slurry, mainly consisting of minerals like kaolin or bentonite, onto a substrate material to alter its surface properties.
Clay content – It is is the proportion of fine-grained mineral particles (typically smaller than 2 micro-meters) present in a soil or material mixture. It is the proportion of clay minerals in a soil mixture, which influences the extent of desiccation cracking, with higher clay content typically leading to higher volumetric shrinkage and increased cracking during drying.
Clay core – It is an impermeable central wall or zone built inside an embankment dam or earthwork to stop water from leaking through.
Clay deposits – These are fine-grained natural soil accumulations mainly composed of hydrous aluminum phyllo-silicate minerals with particle sizes typically smaller than 2 micro-meters to 4 micro-meters.
Clay fill – It is a fine-grained soil material dominated by particles smaller than 2 micro-meters used to raise ground elevations, build embankments, or fill depressions on construction sites.
Clay fraction – It is the proportion of soil particles with an equivalent spherical diameter smaller than 2 micro-meters.
Clay layer – It is a continuous stratum of fine-grained, cohesive soil predominantly composed of hydrated aluminum or magnesium silicates with individual particle sizes strictly less than 2 micro-meters.
Clay minerals – These minerals specifically refer to hydrous aluminum phyllo-silicates, which have a layered structure containing aluminum, silicon, and water. Clays are important in different fields because of their unique properties such as high surface area, cation exchange capacity, and the ability to adsorb water and ions. There are two main types of clay minerals namely detrital, which are transported and deposited sediments, and authigenic, which form in place during diagenesis.
Clay model – It refers to a physical full-scale prototype used in industrial design and automotive styling. It also refers to a constitutive mathematical model (like the cam clay model) used in geo-technical engineering to predict soil behaviour.
Clay nano-particles – These are layered mineral silicates, mainly phyllo-silicates, with at least one dimension measuring in the nano-meter scale (typically under 100 nano-meters).
Clay platelets – These are sheet-like nano-structures formed by stacked alumino-silicate layers which act as high-aspect-ratio reinforcing fillers.
Clay pot – It is a porous ceramic vessel formed from hydrous aluminum silicates and fired at high temperatures, serving as a functional element in thermodynamics, acoustics, and structural material studies.
Clay, refractory – Refractory clay is also called fire-clay. Itis a natural mineral mixture of hydrous aluminum silicates. It resists extreme heat (frequently over 1,500 deg C to 1,770 deg C) without melting, cracking, or losing its shape.
Clays and clay minerals – These are fine-grained materials characterized by their plastic behaviour when wet, and they mainly form through the weathering of silicate rocks, diagenetic reactions, and hydro-thermal alteration.
Clays and gums for coating – These materials for electrode coating are to provide elasticity for extruding the plastic coating material and to help provide strength to the coating.
Clay soil – It is a soil which contains more than 40 % clay, but less than 45 % sand, and less than 40 % silt.
Clay-stone – It is a fine-grained sedimentary rock formed by the compaction and lithification (hardening) of clay-sized particles smaller than 1/256 millimeters (4 micro-meters).
Clay wash – It refers to a liquid suspension of clay particles (frequently mixed with water and refractory materials like silica or graphite) used either as a mould coating / core coating to improve casting surfaces, or as a laboratory procedure, the AFS (American Foundry Society) clay wash test, to separate and measure fine clay content from foundry moulding sand. Clay wash is also a water-rich slurry or liquid mixture used to scour, suspend, or strip fine clay particles and impurities away from valuable solid ores or aggregates. It also refers to the procedural ore washing stage which breaks down sticky, clay-bound mineral feeds.
Clean air act – It is the regulation which is designed to control air pollution on a national level. It is for the protection of the environment from airborne contaminants known to be hazardous to human health.
Clean air act amendments – These are major legislative revisions which establish strict, technology-based standards and enforceable deadlines to control air pollution and hazardous emissions.
Clean coal – It refers to a combination of technologies aimed at reducing the environmental impact of coal energy generation, which includes methods that lower carbon di-oxide (CO2) emissions compared to conventional coal-fired plants and processes which remove impurities to improve the coal’s heating value.
Clean coal technology – It is a collection of applied engineering methods designed to increase power plant efficiency and reduce the environmental impact of coal utilization.
Clean coal technology programme – It refers to a structured government or industry initiative aimed at developing, demonstrating, and commercializing advanced engineering processes which make coal extraction, preparation, conversion, and combustion cleaner and more efficient.
Clean combustion technology – It refers to advanced fuel-burning methods designed to maximize thermal efficiency while minimizing harmful pollutant emissions, such as nitrogen oxides (NOx), carbon mono-oxide (CO), soot, and unburned hydro-carbons.
Clean development mechanism – It is defined in Article 12 of the Kyoto Protocol. Clean development mechanism is intended to meet two objectives namely (i) to assist Parties not included in Annexure I in achieving sustainable development and in contributing to the ultimate objective of the convention, and (ii) to assist Parties included in Annexure I in achieving compliance with their quantified emission limitation and reduction commitments. Certified emission reduction units from clean development mechanism projects undertaken in non-Annexure I countries which limit or reduce greenhouse gas emissions, when certified by operational entities designated by conference of the Parties / meeting of the Parties can be accrued to the investor (government or industry) from Parties in Annexure B. A share of the proceeds from the certified project. A mechanism under the Kyoto protocol through which developed countries can finance greenhouse gas emission reduction or removal projects in developing countries and receive credits for doing so which they can apply towards meeting mandatory limits on their own emissions is known as clean development mechanism.
Clean energy – It refers to power generation and utilization systems which produce little to no green-house gas emissions or environmental pollutants during their operational phase.
Clean energy technology – It is the application of scientific and engineering principles to design, develop, and optimize systems which generate, store, and transmit power with minimal green-house gas emissions and environmental impact.
Cleaner – It is also called scraper. It is a device for removing adherent material from the belt.
Cleaner production – It is a proactive, preventive environmental strategy applied continuously to industrial processes, products, and services to increase efficiency and minimize risks to humans and the environment.
Cleaner production techniques – These are methods which reduce waste and resource consumption in industrial processes, leading to lower operating costs, improved profitability, and higher environmental protection. These techniques contribute to better public relations, compliance with environmental regulations, and increased market competitiveness.
Clean face conveyor belt – With this belt, overall clean environment of lines is enhanced by minimizing debris from transport materials remaining on the return trip with a maximized belt cleaner performance. Belt life span is extended with abrasion resistance twice that of the abrasion resistant grade.
Cleaning – It is the process of chemically or mechanically removing unwanted residue or contaminants (mill scale, rust, dirt, and oil) from the surface of a steel article prior to galvanizing.
Cleaning block – It is an abrasive, eco-friendly tool normally made from recycled glass or pumice-like material designed to scour away stubborn dirt, grease, limescale, and rust without harsh chemicals.
Cleaning chamber – It is a specialized enclosed vessel or reaction zone used to remove accumulated chemical residues, thin-film deposits, or mechanical contaminants from manufactured parts or from the interior surfaces of processing equipment itself.
Cleaning chemicals – These are specialized formulations used in controlled reactions (like hydrolysis, chelation, or solubilization) to dissolve, strip, and remove scale, grease, biofilms, and process residues from industrial equipment, pipelines, and structural surfaces.
Cleaning-emulsifiable solvent – It is a two-stage cleaning system wherein a concentrate containing organic solvents and surface-active agents is applied to a surface, subsequently emulsified, and removed along with the soil, by water rinsing.
Cleaning equipment – It includes specialized tools, devices, and mechanized systems designed to remove surface contaminants, debris, and residues from manufacturing plants, production machinery, and industrial facilities without causing structural damage or leaving residual agents.
Cleaning mechanism – It refers to the physical, chemical, or biological processes used to remove contaminants, residues, or unwanted deposits from a surface or system. It includes mechanical action, chemical reactions, and the use of cleaning agents tailored to the specific type of residue being addressed.
Cleaning of metals and alloys – It is the process of removing surface contaminants, such as oil, grease, oxides, scale, dirt, and machining residues, to prepare the material for subsequent manufacturing, coating, or assembly operations.
Cleaning procedure – It is an established, written, and repeatable method used to remove unwanted residues, contaminants, or soils from equipment, piping, or manufacturing environments to ensure process and product integrity.
Cleaning sequence – It is a structured, repeatable succession of physical, chemical, and thermal steps designed to remove residues, soils, and micro-organisms from industrial equipment or controlled environments.
Cleaning solutions – These are liquids used to remove unwanted residue or contaminants (mill scale, rust, dirt, and oil) from the surface of steel prior to galvanizing. Cleaning solution can be typically an alkali, caustic solution, hydrochloric acid or sulphuric acid, and zinc ammonium chloride flux solution.
Cleaning stage – It is a distinct, controlled operational phase in a multi-step sequence designed to remove particulate, chemical, or biological contaminants from a component, surface, or system.
Cleaning system – It consists of dedicated equipment and mechanisms, including brushes or scrapers, focused on preserving the cleanliness of conveyor components. Regular maintenance is imperative to prevent material build-up and ensure optimal performance.
Clean-in-place – It is an automated method used to clean the interior surfaces of pipes, vessels, and processing equipment without needing to dismantle or take them apart.
Clean-out door – It is a door placed so that accumulated refuse can be removed from the room in a boiler setting.
Clean room – It is a space which maintains a very low concentration of airborne particulates, controlled for contamination, and actively cleansed to protect sensitive manufacturing or testing processes.
Clean steels – These are steels which are obtained after secondary steelmaking and satisfy stringent requirements of surface, internal and micro-cleanliness quality and of mechanical properties. these steels contain limited number of inclusions in terms of size, shape, composition, distribution, and frequency.
Clean surface – It is a surface which is free of foreign material, both visible and invisible.
Clean syngas – It is a processed and purified mixture of hydrogen (H2) and carbon mono-oxide (CO) stripped of harmful contaminants to meet strict industrial or environmental standards. Raw synthesis gas (syngas) directly exiting a gasifier or reformer contains valuable fuel gases (hydrogen and carbon mono-oxide) mixed with impurities. Clean syngas refers to this gas stream after it undergoes rigorous syngas cleanup and conditioning to remove elements which foul catalysts, erode turbines, or violate emissions limits.
Clean syngas technology – It is a process which removes impurities like tars, particulates, sulphur, and heavy metals from raw synthesis gas (a mixture of hydrogen and carbon mono-oxide) so it can be safely used for power, fuels, and chemicals.
Clean technology – It refers to innovative technological solutions aimed at reducing environmental damage by minimizing negative effects on the environment through the reduction or elimination of pollution, waste, and energy consumption.
Clean up – In environmental science, clean up refers to the process of removing pollutants or contaminants from a specific area of the environment, such as soil, water, or air, to mitigate damage to ecosystems and human health, often involving activities like collecting litter, removing hazardous waste, or treating contaminated sites. The technical term for this process is normally called environmental remediation.
Clean-up method – It refers to a systematic procedure or technology used to remove, degrade, or neutralize contaminants, waste, or unwanted by=products from a system, environment, or facility.
Clean water act – It is the regulation which governs water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the waters by preventing point and nonpoint pollution sources with effective utilization of waste-water treatment.
Clearance – It is the gap or space between two mating parts. It is also the space provided between the relief of a cutting tool and the surface which has been cut. Where galvanized components have to fit together (e.g. hinged items, galvanized bolts), sufficient clearance is to be allowed to accommodate the galvanized coating on each surface. In case of cranes, clearance is the vertical distance between the grade level and the bottom of the crane girder.
Clearance fit – It is a connection between two mating parts (like a shaft and a hole) where the largest possible shaft is always smaller than the smallest possible hole, ensuring a continuous gap between them.
Clearance flow – It is the flow which occurs below the minimum controllable flow with the closure member not fully seated.
Clearance, impeller – Impeller clearance is the measured distance or gap between a rotating impeller and the stationary housing, casing, or wear plates inside a pump or mixing equipment.
Clearance volume – It is the residual space remaining in a cylinder, such as in an internal combustion engine or a reciprocating compressor, when the piston is at its highest point, known as top dead centre (TDC). Clearance volume is the volume of the combustion chamber or cylinder head space which is not swept or touched by the piston during its reciprocating stroke.
Clear chill roll – It has a surface layer of white iron produced by inducing rapid cooling at the surface (by means of a chill in the mould) which restricts the formation of free graphite. The core is of grey iron because of the slower rate of cooling and the intermediate zone is a mixture of white iron and grey iron. The necks and wobblers or spade ends are not to be chilled and hence retain greater toughness. The chilled layer is hard and wear resistant but it is brittle. The thickness of the chill varies. It can be even up to 25 mm thick depending upon its application. Beneath the chill zone, there is a transition zone known as ‘Mottle’ zone where carbon is gradually flaking from a few specks to the full flake. The core portion is grey iron. Hardness drops down if the chill is worn out. The chilled layer thickness can be increased where shallow grooves are needed.
Clear fluid – It refers to a liquid which is a poor scatterer of ultrasound, resulting in minimal attenuation as the ultrasound travels through it, which causes it to appear black on ultrasound images.
Clearing point – It mainly refers to a safety margin in railway signaling and track geometry, designating the precise location past a signal or a converging junction where a track is required to remain completely unobstructed for a train to be safely accepted or for rolling stock to pass without a collision. Clearing point is also the specific temperature at which a liquid crystal transitions from an anisotropic liquid crystal phase (where molecules maintain a preferred orientation) into a completely isotropic, clear liquid (where molecular order is entirely lost).
Clearing temperature – It is the specific temperature at which a liquid crystal material completely transitions from its ordered, anisotropic crystalline state into a disordered, isotropic pure liquid state. When a liquid crystal transitions into this isotropic phase, it loses its distinct polarization and light-bending properties (birefringence). Visually, the material changes from a cloudy, milky, or colour-reflecting state and ‘clears; to become completely transparent.
Clear solution – It refers to a liquid mixture where the solute is completely dissolved in the solvent, creating a transparent and homogeneous mixture. This type of solution is characterized by its lack of visible particles or sediment.
Clear span – It is the distance between columns across the width of the building. Building width is defined as the distance from outside of the eave strut of one sidewall to outside of the eave strut of the opposite sidewall. Crane span is the horizontal centre distance between the rails of the runway on which the crane is to travel. Typical distance is around 500 mm less than the width of the building. The requirement of the span of the crane depends on the crane coverage width dictated by the application.
Clear to send frames – These refer to special frames exchanged between devices in a wireless network that indicate a reservation of the medium for transmission, allowing the receiving device to update its network allocation vector (NAV) with the duration of the reservation.
Clear visibility – It refers to an optimal atmospheric or optical condition where visual contrast is unaltered, and an observer or sensor can discern objects and lights over the maximum theoretically possible distance without obstruction from fog, haze, smoke, or precipitation.
Cleat – It consists of an attachment affixed to the conveying surface, serving different purposes such as pushing, supporting, checking, or tripping, aiding in the smooth movement of material along the conveyor path.
Cleat height – It is the vertical measurement of raised portions (cleats) on a conveyor belt, demanding periodic checks for wear and precise positioning.
Cleated belt – It is a belt equipped with cleats featuring elevated sections, ensuring the firm positioning of units during travel on slopes.
Cleated belt conveyor – It is a belt designed with uniformly spaced raised sections to stabilize material flow, particularly effective on inclined belts; cleats may be an integral part of the belt or attached separately.
Cleat system – It is two sets of open and / or closed fractures or joints in coal beds, including face cleats which are more continuous and butt cleats which are orthogonal to face cleats. This system characterizes the three-dimensional network of cleats, influencing the connectivity and permeability of the coal reservoir for fluid flow.
Cleavage – It is the fracture of a crystal by crack propagation across a crystallographic plane of low index. It is also the tendency to cleave or split along definite crystallographic planes.
Cleavage crack – It is a crack which extends along a plane of easy cleavage in a crystalline material.
Cleavage fracture – It is a fracture, normally of a polycrystalline metal, in which majority of the grains have failed by cleavage, resulting in bright reflecting facets. It is one type of crystalline fracture and is associated with low-energy brittle fracture.
Cleavage plane – It is a characteristic crystallographic plane or set of planes in a crystal on which cleavage fracture occurs easily.
Cleavage stress – It is a prying or pulling force concentrated heavily along one edge of a bonded joint between two rigid substrates, leaving the opposite edge under little to no stress. Unlike tensile or shear stresses, which spread forces evenly across the entire surface area, cleavage stress acts like a lever, focusing the entire breaking load onto a single narrow line or edge.
Cleavage test – It is a mechanical test used to measure the resistance of adhesively bonded joints or materials to splitting and crack propagation under tensile stress.
Clevis pin – It is a ‘U’ shaped connecting yoke at the end of a stem, between the ends of which a gate or other part can be pinned or bolted. It allows rotation of the connected parts about the axis of the pin.
Client – A client can be any individual, organization, or device which engages the services of another individual, organization, or device. An organization can have several clients.
Client device – It is a hardware or software component in a client-server model which initiates a request to a server for data, resources, or services.
Client-server model – It is a software and network design where tasks and work-loads are split between service requesters (clients) and service providers (servers).
Client transaction – It is a single, logical unit of work initiated by a client component which manages request dispatch, state tracking, and atomicity (commit or rollback) across a server or network boundary.
Cliff edge effect – It is a significant consequence which is disproportionate to the change that caused it.
Climate – Climate in a narrow sense is normally defined as the average weather, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is 30 years, as defined by the World Meteorological Organization. The relevant quantities are very frequently surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.
Climate change – It is a change in the state of the climate which can be identified (e.g., by using statistical tests) by changes in the mean and / or the variability of its properties and which persists for an extended period, typically decades or longer. Climate change can be because of the natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use. Climate change refers to long-term shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in the sun’s activity or large volcanic eruptions. But since the 1800s, human activities have been the main driver of climate change, mainly because of the burning of fossil fuels like coal, oil and gas. The main green-house gases which are causing climate change include carbon di-oxide and methane. Clearing land and cutting down forests can also release carbon dioxide. Agriculture, oil and gas operations are major sources of methane emissions. Energy, industry, transport, buildings, agriculture and land use are among the main sectors causing green-house gases.
Climate change effects – These effects refer to the physical and environmental impacts, such as extreme weather, rising sea levels, and shifting temperatures, which infrastructure and systems are to be designed to withstand. Climate change effects are environmental pressures caused by green-house gas emissions which threaten structures, coastal zones, and industrial operations.
Climate change impacts – It is the effect of climate change on natural and human systems. Depending on the consideration of adaptation, one can distinguish between potential impacts and residual impacts.
Climate change impact assessment – It consists of assessment of the impacts which affect ecosystems or human welfare but which are not directly linked to market transactions, for example, an increased risk of premature death. It is the analysis of positive and negative consequences of climate changes on natural systems and human societies, both with and without adaptation to such changes.
Climate change mitigation – It consists of the strategies and policies which reduce the concentration of green-house gases in the atmosphere either by reducing their emissions or by increasing their capture.
Climate change mitigation technology – It refers to the design, development, and application of systems, materials, and processes intended to permanently eliminate or reduce green-house gas emissions and remove carbon di-oxide from the atmosphere.
Climate change scenario – It is a plausible, science-based ‘what-if’ story of how future climate conditions can unfold, based on different levels of green-house gas emissions, population growth, and economic choices. These scenarios are used not as exact predictions, but as stress-tests to design resilient infrastructure, like bridges, drainage systems, and power grids, which can withstand future extremes like higher temperatures, sea-level rise, or heavier rainfall.
Climate factors – These factors refer to the long-term meteorological elements and environmental conditions, such as temperature, precipitation, wind, humidity, and atmospheric pressure, which characterize a region and directly influence the design, safety, performance, and durability of infrastructure and machinery.
Climate model – It is a computer-based mathematical simulation of the earth’s climate system, including the atmosphere, oceans, land surface, and ice, used to project future environmental conditions and long-term trends.
Climate regulation – It is the ecosystem service which regulates processes related to atmospheric chemical composition, the green-house effect, the ozone layer, precipitation, air quality, and moderation of temperature and weather patterns (including cloud formation), at both global and local scales.
Climate system – It is the highly complex system consisting of five major components namely the atmosphere, the oceans, the cryosphere, the land surface, the biosphere, and the interactions between them. The climate system evolves in time under the influence of its own internal dynamics and because of external forcings such as volcanic eruptions, solar variations, and anthropogenic forcings such as the changing composition of the atmosphere and land use change.
Climate threshold – It is a critical limit within the climate system which induces a non-linear response to a given forcing.
Climate variability – It refers to variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate at all spatial and temporal scales beyond that of individual weather events. Variability can be because of the natural internal processes within the climate system (internal variability), or because of the variations in natural or anthropogenic external forcing (external variability).
Climate variables – These are measurable physical, chemical, or biological factors which track how earth’s atmosphere, land, and oceans behave over time. The global climate observing system (GCOS) defines 55 essential climate variables (ECVs) to characterize the global climate system, support the Inter-governmental Panel on Climate Change (IPCC), and guide climate science and policy.
Climatic chamber – It is a controlled, enclosed testing device which simulates specific outdoor or indoor environmental conditions, mainly temperature and humidity, to test the durability and performance of products and materials. Climatic chamber is a controlled experimental setup which simulates outdoor and indoor environmental conditions, allowing for precise manipulation of variables such as temperature and solar flux for research purposes.
Climatic conditions – It means the long-term, average weather patterns and atmospheric states of a specific region, normally calculated over a period of 30 years or more. Key elements considered are temperature, precipitation, humidity, wind, and atmospheric pressure.
Climatic cycle – It is a recurring, quasi-periodic pattern of global or regional climate fluctuations driven by astronomical, atmospheric, or oceanic processes.
Climatic system – It refers to the integrated network of physical components, control loops, and thermodynamic processes used to regulate interior or localized environmental conditions (such as temperature, humidity, and airflow) or the study of earth’s natural climate system for infrastructure design and geo-engineering.
Climb – It means dislocation climb. It is a high-temperature deformation process where an edge dislocation moves perpendicularly out of its original slip plane. Unlike glide (which moves along the plane under shear stress), climb is a non-conservative, thermally activated motion driven by the diffusion and absorption or emission of point defects like vacancies or interstitials.
Climb cutting – It is analogous to climb milling.
Climbing drum peel test – It is a standardized method used to measure the peel resistance and adhesive bond strength between a relatively flexible skin (facings) and a rigid substrate or core (such as a honeycomb sandwich structure).
Climbing formwork – It is a special climbing formwork system used to build tall, vertical concrete structures like high-rise building cores, bridge towers, and elevator shafts. It acts as a temporary mould and working platform which supports fresh concrete. Instead of dismantling and reassembling the forms at each floor, the entire system ‘climbs. up the structure as each new section of concrete hardens.
Climbing robot – It is an autonomous or semi-autonomous machine designed to move along vertical, inclined, or inverted non-horizontal surfaces (such as walls, pipelines, towers, and cables) while performing tasks like inspection, maintenance, or construction.
Climb milling – It is milling in which the cutter moves in the direction of feed at the point of contact.
Climb of edge dislocation – It is the vertical movement of an edge dislocation out of its original slip plane onto a parallel plane, driven by atomic diffusion and the absorption or emission of vacancies.
Climb velocity – It is the speed at which an edge dislocation moves out of its slip plane through the addition or removal of point defects (vacancies or interstitial atoms).
Clinical significance – It is the condition in which sample results which are significant and are also clinically meaningful. It refers to the importance of the outcomes measured in a study and the magnitude of the differences observed, emphasizing that statistically significant results are also be meaningful to be considered useful.
Clinker – It is a solid material produced in the manufacture of portland cement as an intermediary product. Clinker occurs as lumps or nodules, normally 3 millimeters to 25 millimeters in diameter. It is produced by sintering (fusing together without melting to the point of liquefaction) limestone and alumino-silicate materials such as clay during the cement kiln stage. It is also fused or partially fused fuel ash which can contain some incompletely burned fuel. Clinker is a dead burned product normally stabilized dolomite.
Clinkerization – It is the high-temperature pyro-processing stage in cement manufacturing where raw material blends are heated to partial fusion to form cement clinker.
Clinkerization process – It converts finely ground raw materials (raw meal) into hydraulic cement clinker inside a rotary kiln. It is a method which is used to convert raw materials into clinker through high-temperature treatment, which can be optimized by different technologies such as fluidized bed systems to improve thermal efficiency and reduce emissions.
Clinker production – It is the high-temperature pyro-processing of raw materials like limestone, clay, and iron oxides inside a rotary kiln at roughly 1,450 deg C to create dark gray, nodular intermediate lumps which are subsequently ground with gypsum to manufacture Portland cement.
Clinopyroxene – It is a group of silicate minerals belonging to the pyroxene family which crystallize in the monoclinic crystal system. It is rich in calcium, magnesium, iron, and sodium, following a general formula such as XYZ2O6. Common examples are augite, diopside, jadeite, and hedenbergite. It is found widely in different igneous and metamorphic rocks, typically forming at higher temperatures than amphiboles.
Clinopyroxenite – It is a coarse-grained igneous rock. It contains more than 90 % clinopyroxene (such as augite, diopside, or hedenbergite). It is an ultramafic rock, meaning it has very low silica and high magnesium and iron content. Its texture is phaneritic, meaning the mineral crystals are large enough to see with the naked eye. It can include small quantities of olivine, ortho-pyroxene, hornblende, or garnet.
Clip angle – It is a short piece of structural steel angle used as a connector in framing joints to join elements like beams to columns or girders.
Clipper lacing – It is a lacing method which involves the use of a clipper lacing machine to attach lacing securely to the conveyor belt.
Clipping level – It is the highest input or output amplitude an amplifier or circuit can handle before the waveform gets flattened. It shows up in voltage regulation, op-amp limits, and clipping circuits. Clipping level is the amplitude limit where an electrical signal stops being reproduced cleanly and starts getting cut off.
Clipping noise – It is a form of wave-form distortion which happens when a signal exceeds the maximum capacity, voltage limit, or threshold of a circuit, amplifier, or digital system.
Clock (Clk) and reset – These are the two most critical control signals used to manage how data moves through a circuit. They synchronize operations and ensure the system starts in a predictable state.
Clock cycle – It the single smallest unit of time which defines the rhythm and synchronization of a synchronous digital system or central processing unit (CPU). It is the time interval between two matching parts of a repetitive clock signal, such as between consecutive rising edges of an oscillating square wave.
Clock delay – It is the time it takes for a clock signal to travel from its original source to a destination endpoint (sink) like a flip-flop. Clock delay (or propagation delay) is the fixed or variable time it takes for a clock signal or data packet to travel from its source to a destination circuit or node.
Clock drift – It is the gradual desynchronization or divergence of a device’s internal clock from a reference clock over time, caused by hardware imperfections, aging, and temperature changes. It is the phenomenon where the clock of a sensor node becomes imprecise over time, leading to synchronization errors because of variations caused by factors such as differences in sensor quality and environmental influences like temperature and moisture.
Clock feed-through – It can refer to two entirely different concepts depending on whether one is analyzing analog switch dynamics or digital layout constraints (feedthrough paths). In analog and mixed-signal electronics (like sample-and-hold circuits or analog to digital converters), clock feed-through is the undesirable capacitive coupling of a clock signal directly into the signal path. In digital IC (integrated circuit) design and static timing analysis (STA), a feed-through condition or feed-through path occurs during hierarchical design partitioning.
Clock frequency – It is the speed at which a processor executes instructions, measured in hertz (Hz) as the number of clock cycles per second, while delay refers to the time it takes for a signal to propagate through logic gates or for a clock signal to reach a register.
Clock latency – It is the total time a clock signal takes to travel from its absolute source to a destination sink (such as a flip-flop’s clock pin) in a VLSI (very large-scale integration) circuit.
Clock period – It is the total time it takes for a single, complete cycle of a periodic clock signal to occur in a digital circuit. It is the fundamental time interval that synchronizes operations inside a processor or digital system.
Clock pulse – It is a periodic, repetitive electronic signal, normally shaped like a square wave, used to coordinate and synchronize the timing of state changes in digital and sequential logic circuits.
Clock recovery – It is the process of extracting timing and frequency information directly from an incoming serial data stream so a receiver can decode the transmitted symbols without a separate, dedicated clock wire.
Clock recovery circuit – It is an electronic component which extracts a synchronized timing clock directly from an incoming serial data stream, allowing a receiver to decode data correctly without a separate dedicated clock wire.
Clock signal – It is a periodic electronic voltage or current waveform which oscillates between high and low logic states to synchronize the operations of digital circuits.
Clogging – In its general sense, it means becoming blocked or filled, making movement or activity difficult. It can refer to physical obstructions, like clogging of a water spraying nozzle. In continued casting (CC), clogging specifically refers to the blockage of a submerged entry nozzle (SEN), frequently because of the formation of solid materials or inclusions within the molten metal.
Close annealing – It is annealing a metal or alloy in a sealed container under conditions which minimize oxidation. In box annealing a ferrous alloy, the charge is normally heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly. This process is also called box annealing or pot annealing.
Close-contact melting – It is a phase-change heat transfer phenomenon where a solid body (typically a phase change material) is pressed against a hot surface, maintaining separation through a microscopic, self-sustaining liquid film.
Closed belt conveyor – In a closed belt conveyor, the specially fabricated belt, after being loaded with the material, can be wrapped completely around the load. It essentially forms a closed tube moving along with the material. The advantages of a closed belt conveyor are (i) it can handle fragile materials safely and without breaking by reducing inter-particle collision, (ii) it can handle fine bulk materials without being swept by air though, it is not really air tight at loading and unloading points, (iii) it has ability to handle corrosive and reactive materials without contamination, and (iv) the tubed belt can travel around bends in more than one plane and hence versatile in layout. The lengths of these conveyors are normally limited.
Closed belt system – It is a material transport design where the moving belt and its cargo are fully covered or sealed inside a protective housing. This set-up shields goods from weather elements like rain, prevents fine powders or dust from escaping into the air, and protects sensitive items from outside contamination.
Closed Brayton cycle – It is a thermodynamic power generation system where the same working gas recirculates continuously through a closed loop without being exchanged with the atmosphere.
Closed-cell foam – It is a type of spray insulation where the cells are completely closed, preventing air and moisture from being trapped inside. This material is characterized by its rigidity and stability, occupying 40 % less space than fibre-glass for equivalent thermal resistance.
Closed-cell structure – It refers to a cellular material made of completely sealed, discrete pockets of gas or air which do not connect with neighbouring cells.
Closed circuit – It is an uninterrupted path for electric current to flow, forming a complete loop. In a closed circuit, the current can travel from the power source, through the circuit’s components, and back to the source without any breaks. This continuous flow of electricity allows devices like light bulbs or motors to function.
Closed circular reservoir – It refers to a cylindrical underground geological formation containing fluids (like oil, gas, or water) enclosed by a sealed, impermeable outer boundary, or it is a fully enclosed circular man-made tank structure used for liquid storage.
Closed contour – It is a continuous loop of an imaginary line connecting points of equal elevation which starts and ends at the same place without intersecting itself. Hills and mountains are represented by concentric closed contours where the elevation values increase toward the center. Depressions or ponds are represented by concentric closed contours where the elevation values decrease toward the centre (frequently marked with tick / hatch marks pointing inward).
Closed conveyor system – It is a conveyor system which is enclosed within a structure, demanding specialized maintenance to uphold optimal functionality and prevent material spillage.
Closed cross section – It is a structural profile with a continuous, completely enclosed outer perimeter which forms a closed loop. Closed cross sections enclose a space, providing resistance to twisting and bending when subjected to external loads, such as equal and opposite end torque.
Closed-cycle machine – It is a thermal or fluid-handling mechanical system where the working fluid stays inside a sealed loop and is recirculated continuously rather than being released into the atmosphere.
Closed-cycle machinery system – It is a mechanical arrangement where a working fluid circulates continuously in a closed loop without being discharged into or replenished from the outside atmosphere.
Closed-die coining – It is a precision cold-forming process where a metal work-piece is squeezed between two completely closed dies using extremely high pressure to create fine surface details, tight tolerances, and smooth finishes.
Closed-die forgeability – It is a metal’s capacity to deform under compressive forces inside a closed die cavity without cracking, tearing, or forming internal flaws, while completely filling the intricate shapes of the die.
Closed-die forging – It is the shaping of hot metal completely within the walls or cavities of two dies which come together to enclose the work-piece on all sides. The impression for the forging can be entirely either die or divided between the top and bottom dies. Impression-die forging, frequently used interchangeably with the term closed-die forging, refers to a closed-die operation in which the dies contain a provision for controlling the flow of excess material, or flash, that is generated. By contrast, in the flash-less forging, the material is deformed in a cavity which allows little or no escape of excess material. Closed die forging is performed by squeezing the raw material called billet inside the cavity formed between a pair of shaped dies. Forged products achieve the shape of the die cavity. Valve parts, pump parts, small gears, and connecting rods, spanners etc. are produced by closed die forging.
Closed dies – These are forging or forming impression dies designed to restrict the flow of metal to the cavity within the die set, as opposed to open dies, in which there is little or no restriction to lateral flow.
Closed-die tooling – It refers to custom-machined metal blocks with engraved negative cavities that squeeze a heated raw material into a precise, complex 3D shape.
Closed-form expression – It is a mathematical formula which can be calculated in a fixed, finite number of standard operations.
Closed-form solution – It is an exact expression which solves a problem using a finite number of standard operations and elementary functions, without needing iterative or infinite processes.
Closed fuel cycle – It is a nuclear fuel management system where spent reactor fuel is chemically reprocessed to recover and recycle unused uranium and plutonium into new fuel.
Closed gas reservoir – It is a subsurface geological formation containing natural gas which operates as a volumetric system with no water influx or external mass boundaries crossing its outer edges during production.
Closed green-house system – It is an innovative horticultural engineering system where all roof ventilation windows are permanently sealed, replacing traditional natural ventilation with active mechanical air treatment and advanced energy management.
Closed interval – It is a range of numbers or values which includes all numbers between two endpoints as well as the endpoints themselves. It is written using square brackets as [a, b]
Closed ion source – It is a type of ion source in a mass spectrometer where the pressure in the ionization region is maintained at a higher pressure than the rest of the analyzer, typically by using a solid-walled tube for the anode. This allows for direct sampling of the gas at process pressure, leading to higher sensitivity and faster response times.
Closed-loop Brayton cycle – It is a continuous thermodynamic power generation system where a single working fluid circulates in a sealed loop, receiving and rejecting heat through external heat exchangers rather than exchanging gas with the atmosphere.
Closed-loop control – Closed-loop control of a system offers the possibility to dynamically adjust its inputs in order to follow a reference set point, and to reduce the effect of the perturbations from the system’s environment. Closed-loop control is achieved by adding more complexity to the system, and this makes it more vulnerable. Digital controllers have to be added and tuned, so are sensors, which are needed to close the loop. But the benefits in terms of robustness and improved performance, e.g., efficiency, always justify the cost, provided that a clear and systematic methodology can be adopted to design the control.
Closed-loop recycling – It is the process by which a product or material can be used and then turned into a new product (or converted back to raw material) indefinitely without losing its properties during the recycling process. By reducing the production and use of raw materials, closed-loop recycling minimizes harm to the environment and discourages resource depletion. Ideal closed-loop systems produce no waste.
Closed-loop system stability – It is the condition where a feed-back control system produces a bounded output for a bounded input, meaning its response settles to a steady state or equilibrium rather than growing uncontrollably over time.
Closed pass – It is a pass of metal through rolls where the bottom roll has a groove deeper than the bar being rolled and the top roll has a collar fitting into the groove, hence producing the desired shape free from flash or fin.
Closed path – It is a continuous route or traversal which starts and ends at the exact same point or vertex.
Closed plant – It refers to a closed-cycle power plant or a closed-loop system where the working fluid or material recirculates continuously within a sealed circuit without mixing with the external environment or combustion products.
Closed pores – These are the pores which are enclosed within a refractory and are not penetrated by the immersion liquid in the test specified in International Organization for Standardization standard ISO 5017. In principle, these pores are those which are not connected to the atmosphere, either directly or through one another.
Closed pore structure – It refers to a porous configuration where individual voids or pores are fully sealed and isolated within the solid matrix, meaning they do not interconnect with each other or open to the external surface.
Closed porosity – It is the ratio of the total volume of the closed pores in a porous refractory to its bulk volume, which is expressed as a percentage of the bulk volume.
Closed process – It refers to a manufacturing or operational system where the product, materials, and critical contact surfaces are completely contained and isolated from the immediate external room environment.
Closed-reaction system – It is a framework where the system’s output has a direct effect on the control action. Unlike an open-loop system which executes commands blindly, a closed-reaction system automatically adjusts its inputs based on real-time feed-back to achieve and maintain a desired target state.
Closed section beam – It is a structural member whose cross-sectional profile forms a complete, continuous loop rather than having open edges. A closed section (such as a hollow circular tube, square / rectangular box section, or a single-cell fuselage) encloses a continuous perimeter, whereas an open section (like an I-beam, C-channel, or T-section) features free, unjoined edges.
Closed steam – It refers to steam which circulates within a sealed, pressurized loop where water or steam undergoes thermodynamic changes and returns entirely to the boiler for reuse without venting or contacting the atmosphere.
Closed surface – It is a continuous two-dimensional boundary which completely encloses a distinct volume in three-dimensional space with no exposed edges or holes.
Closed system – It is a thermodynamic system which undergoes no interchange of mass (materials) with its surroundings. A closed system, however, can interchange energy with its surroundings.
Closed test section – It mainly refers to a specific configuration used in wind tunnels and fluid dynamics testing. It is a component of a wind tunnel circuit where the air-stream and the test model are completely enclosed by solid walls (typically made of metal or clear acrylic for viewing). This stands in contrast to an open test section, where the air-flow passes through the testing zone as an open jet without physical side walls.
Closed thermodynamic system – It is a system which allows the transfer of energy (as heat or work) across its boundaries, but strictly prohibits the transfer of mass.
Closed-tolerance, no-draft forging – It is a precision closed-die forging manufactured with tighter-than-normal dimensional limits and a zero-degree draft angle (0-degree), meaning the vertical walls of the part are completely parallel rather than tapered.
Closed-tolerance tooling – It refers to specialized metal-forming equipment, such as precision dies, moulds, or stamps, engineered to manufacture parts within extremely tight and accurate dimensional limits.
Closed trajectory – It is a path of motion or a system state cycle which loops back onto itself, meaning the starting point and ending point in space or phase space are identical after a finite time period.
Closed-trough conveyor – It is frequently synonymous with a pipe conveyor or fully enclosed troughed belt system. It is a specialized bulk material handling system where the edges of a flexible conveyor belt are overlapped or formed into a sealed ‘pipe’ or closed U-shape by special idler rollers. This design completely contains the material inside a protective, dust-free enclosure during transit.
Closed type housings – These are one piece cast housings of simple form (rectangular section) which are used for heavy roughing mills. These housings are either cast housings or welded housings fabricated from forged steel. Fabricated housings can be made quickly without waiting for patterns and castings. Several old cast iron housings are extremely heavy since they are not forged, and due to inherent imperfections during the casting process, had to be twice as large as a superior forged housing. Such housings are to be made very heavy because of the possibility of cracking. This is very common with large cast housing.
Close mechanical members – These members refer to adjacent or contiguous components in a mechanism or structure which maintain permanent or intermittent contact while permitting specific relative motion or force transfer.
Close over – It is the foundry operation of lowering the top mould half (cope) over a projecting internal part like a sand core or deep pocket before pouring molten metal.
Close-packed – It is a geometric arrangement in which a collection of equally sized spheres (atoms) can be packed together in a minimum total volume.
Close-packed hexagonal – It is a crystal structure where atoms or spheres stack in an alternating ABAB pattern to achieve maximum spatial density and stability.
Close-packed structure – It is an efficient, space-filling arrangement of atoms, modelled as hard spheres, where empty space is minimized to achieve maximum atomic density.
Close proximity – It means a targeted physical, electrical, or spatial condition where two or more elements are close enough to interact through forces, fields, or direct physical contact.
Closest node – It refers to the graph, mesh, or network vertex which minimizes the spatial or topological distance (such as Euclidean distance or hop count) to a specified reference point, coordinate, or target node.
Close tolerance – Close tolerance refers to the application of precise geometrical requirements on engineering drawings, especially for surfaces which interact with other parts, when tight tolerances are necessary to ensure proper functionality and repeatability.
Close-tolerance forging– It is a forging held to unusually close dimensional tolerances so that little or no machining is needed after forging.
Close trim – It is a secondary trimming operation where the excess metal (flash) is sheared or cut extremely close to the actual forged component body, leaving minimal residual stub or land width.
Close valve – It is a mechanical device which is used to completely stop or allow the flow of fluids (liquids, gases, or slurries) through a pipe.
Closing pressure – It is the exact system pressure at which a safety or pressure-relief valve reseats completely and stops discharging after releasing excess pressure. It is normally set below the initial opening or set pressure (e.g., 10 % to 20 % lower, depending on the fluid media and standards used).
Closure – It is the complete coverage of a mandrel with one layer (two plies) of fibre. When the last tape circuit which completes mandrel coverage lays down adjacent to the first without gaps or overlaps, the wind pattern is said to have ‘closed’. It is also the ends of a ball valve bolted to the body which normally contain the seat rings. It is frequently referred to as part of the body.
Closure domain – It is a specialized magnetic or polar structure which forms at the surface or edges of a material to complete an internal magnetic flux circuit and reduce magnetostatic energy.
Closure element – It is the moving part of a valve, positioned in the flow stream which controls flow through the valve. Ball, gate, plug, clapper, disc, etc. are specific names for closure elements. It is also termed as Obturator.
Closure member – It is the movable part of the valve which is positioned in the flow path to modulate the rate of flow through the valve.
Closure member guide – It is that portion of a closure member which aligns its movement in either a cage, seat ring (port guiding), bonnet, bottom flange, stem, or any two of these.
Closure pours – It is a small, specialized section of a concrete structure, such as a bridge deck or large building slab, left unpoured during initial construction and filled in last to connect adjacent structural elements. Closure pour is a concrete pour which conforms to construction drawings and is implemented as directed by the designer, featuring compressive strength equal to or higher than the precast elements, typically 35 mega-pascals, and incorporating specific curing and admixture requirements to improve durability and prevent cracking.
Closure pressure – It is the fluid pressure at which an induced hydraulic fracture in a rock formation mechanically closes after fluid injection stops.
Closure tolerance – It refers to the allowable dimensional variation across a part’s parting plane caused by the gap or ‘closure’ variation between upper and lower forging dies.
Cloud application – It is a software programme which runs its processing logic and data storage across remote servers and local devices, accessed mainly through the internet. It is a software which splits tasks between client-side interfaces (like a web browser) and remote server-side infrastructure.
Cloud computing – It is the on-demand delivery of computing resources, such as servers, storage, databases, and software tools, over the internet on a pay-as-one-go basis.
Cloud computing services – These refer to the provision of shared resources for data storage and computation over the Internet, utilizing distributed data centres managed by different service providers.
Cloud, engineering – Engineering cloud refers to cloud storage and computing (CSC) services that provide flexible, scalable, and cost-effective access to high computing power, enabling rapid innovation and collaboration in engineering projects. It allows engineers to focus on core functionalities while leveraging resources for developing and validating technologies without the need for on-premises infrastructure.
Cloud point – It is the temperature at which the lubricant becomes cloudy or hazy when cooled. It indicates suitability of the lubricant in cold conditions and hence is to be low. Lubricating oils used in capillary feed systems need to have low cloud points, otherwise impurities clog the capillary.
Cloud seeding – It is a weather modification technique that improves a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into certain types of subfreezing clouds. These nuclei provide a base for snowflakes to form. After cloud seeding takes place, the newly formed snowflakes quickly grow and fall from the clouds back to the surface of the earth in the form of precipitation. It is also known as artificial rain.
Cloud service provider – It is the entity responsible for making cloud services available to consumers, which includes acquiring and managing the necessary computing infrastructure, as well as installing, managing, maintaining, and supporting software applications within a cloud environment.
Cloud-to-ground lightning – It is a luminous, high-current electric discharge which flows from a cloud to the ground, typically occurring in association with thunder-clouds.
CLU process – CLU process is similar to the AOD (argon oxygen decarburization) process for making stainless steels. CLU refers to the Creusot-Loire Uddeholm process for stainless steel production. It also uses liquid steel from an electric arc furnace or any other similar primary steel making furnace. The major impetus for the development of the CLU process was the idea to use superheated steam as the diluting gas instead of argon gas which is used in the AOD process. It is carried out either in a bottom blown converter or a side blown converter.
Cluster algorithm – It is a method used to partition unlabelled data into distinct groups based on their similarity, with types including partitioning-based, hierarchical-based, density-based, grid-based, and model-based approaches.
Cluster analysis – This method is used to classify objects or individuals. For this purpose, mutual groups are constructed to maximize both the homogeneity and heterogeneity between clusters. Factor analysis groups variables as factors, while the cluster method groups objects or people together by considering different criteria.
Cluster communication – It refers to the interaction and data exchange among interconnected nodes within a grouped network topology, operating either to aggregate sensor data or synchronize distributed computing resources.
Cluster formation – It is the process of organizing individual system nodes, devices, or data points into structured, localized groups to optimize performance, energy usage, and scalability.
Cluster head – It is a node which initiates the maintenance process by monitoring other nodes within its cluster, managing communication links, and facilitating neighbour discovery while considering security aspects and backup leadership when necessary.
Cluster head candidate – It in engineering is in engineering is a network node which meets specific eligibility criteria, such as having sufficient residual battery energy, high connectivity, or an optimal spatial position, allowing it to be nominated or considered for election as a leader (cluster head) in a clustered network architecture like a wireless sensor network (WSN) or mobile ad-hoc network (MANET).
Clustering algorithm – It is a computational method used to establish pattern similarities in data, allowing for the classification of data showing similar characteristics into corresponding target groups. Examples include hierarchical, expectation maximization, k-medians, and k-means clustering approaches.
Clustering criterion – It is a mathematical objective function or set of rules used to evaluate how well a given data partition groups similar objects together.
Clustering problem – It is the unsupervised machine learning challenge of grouping unlabeled data points or physical objects based on shared characteristics and similarity measures without prior behavioural information.
Clustering protocol – It is a structured method which groups nearby network nodes or devices into localized groups called clusters to improve communication efficiency, scalability, and energy management.
Cluster member – It is individual node, device, or server within a grouped network which shares work-loads, states, and resources to act as a single cooperative system.
Cluster mill – It is a rolling mill in which each of the two working rolls of small diameter is supported by two or more larger diameter back-up rolls.
Cluster mill roll configuration – In this type of roll configuration, there are six, seven, twelve, or twenty horizontally mounted rolls. In all the mills having this configuration, there are only two rolls which are work rolls while all the other rolls are back-up rolls. Normally work rolls are driven and back-up rolls are friction driven. The multi-roll mill configuration is used for cold rolling of very thin sheets, strips and foils.
Cluster sampling – It is a type of sampling whereby observations are selected at random from several clusters instead of at random from the entire population. It is intended that the heterogeneity in the phenomenon of interest is reflected within the clusters, i.e., members in the clusters are not homogenous with respect to the response variable. Cluster sampling is less satisfactory from a statistical stand-point, but frequently can be more economical and / or practical.
Clutch – It is a mechanical device which allows an output shaft to be disconnected from a rotating input shaft. The clutch’s input shaft is typically attached to a motor, while the clutch’s output shaft is connected to the mechanism that does the work.
Clutch and brake shears – These are of an older design, but can benefit from new automation, though accuracy and repeatability are limited by clutch and brake system performance. The main advantage of this type of the shear is the possibility of fine-tuning clutch and brake timing to optimize accuracy and friction material life.
Clutch drive – It is a drive mechanism facilitating the disengagement of the motor from the reducer without stopping the motor or cutting power.
Clutch-drive brake – It is a drive system enabling the disengagement of the motor from the reducer and an immediate halt to conveyor movement without stopping the motor or cutting power.
CNC direct die sinking – It is a computer-numerical controlled (CNC) electrical discharge machining (EDM) process which uses thermal sparks to melt and vapourize material from a conductive metal block to form precise blind cavities or moulds.
CO2 capture – It is the process of selectively separating carbon di-oxide (CO2) from industrial flue gases, process streams, or the ambient atmosphere before it can escape into the environment.
CO2 capture and storage – It is a process which prevents anthropogenic (human-made) carbon di-oxide (CO2) from entering the atmosphere. It captures waste CO2 from large industrial point sources or direct air, compresses it, and permanently isolates it underground.
CO2 capture, storage, and utilization – It refers to the processes involved in capturing carbon di-oxide emissions from sources such as flue gas or the atmosphere, storing it to prevent its release into the environment, and utilizing it in several applications. These processes face challenges including high costs, energy penalties, and the need for improved technologies and solvents.
CO2 capture, utilization, and storage – It refers to an integrated suite of technologies designed to separate carbon di-oxide (CO2) emissions from industrial point sources (such as power plants, cement kilns, or steel plants) or directly from the atmosphere (direct air capture), compress and transport the gas, and either permanently sequester it or convert it into commercial products.
CO2 conversion – It is the chemical, electro-chemical, photo-chemical, thermal, or biological process of using carbon di-oxide (CO2) as a raw feedstock to transform it into valuable industrial materials, fuels, and chemicals.
CO2 emissions – These are the total mass of carbon di-oxide (CO2) released into the atmosphere as a direct or indirect result of a mechanical, chemical, or energy-conversion process.
CO2 hydrogenation – It is a catalytic chemical reaction which combines carbon di-oxide (CO2) with molecular hydrogen (H2) to convert the greenhouse gas into valuable chemical feedstocks and clean fuels such as methanol (CH3OH), carbon mono-oxide (CO), methane (CH4), and higher hydro-carbons (C2+).
CO2 liquefaction – It is the process of compressing and cooling carbon di-oxide (CO2) to convert it from a gaseous state into a liquid state, typically achieved through methods like low-pressure refrigeration or high-pressure compression with free liquid expansion. This process involves achieving specific pressures and temperatures, such as cooling carbon di-oxide below its critical temperature and expanding it adiabatically.
CO2 process – It is the process by which moulds and cores, made with sand containing sodium silicate, are hardened by permeating the sand with carbon di-oxide gas.
CO2 sequestration – It is the process of capturing, separating, compressing, and permanently storing carbon di-oxide from industrial sources or the atmosphere in long-term subsurface or engineered reservoirs to prevent its release into the environment.
CO2 storage – It refers to the process of capturing carbon di-oxide (CO2) from industrial point sources or the atmosphere, compressing it into a dense or supercritical phase, and injecting it deep underground into geological formations for permanent isolation. It is the placement of anthropogenic CO2 into a subsurface repository (typically at depths higher than 800 meters) so that it remains safely and permanently stored.
Coagulant – It is a chemical substance added to liquid suspensions or waste-water to neutralize electrical charges on tiny suspended particles, allowing them to clump together.
Coagulant aid – It is a supplementary chemical or material added during water and wastewater treatment to improve, assist, or modify the main coagulation-flocculation process.
Coagulant sludge – It is the main residual waste generated during water and waste-water treatment when metal salts or polymers are added to destabilize and precipitate suspended impurities.
Coagulation – It is a process of aggregation or accumulation of colloidal particles to settle down as a precipitate. In water treatment, coagulation involves the addition of compounds which promote the clumping of fine colloidal particles into larger particles so that they can be more easily separated from the water. Coagulation is a chemical process which involves neutralization of charge. whereas flocculation is a physical process and does not involve neutralization of charge. Iron and aluminium salts are the most widely used coagulants but salts of other metals such as titanium and zirconium have been found to be highly effective as well. Coagulation is affected by (i) the type of coagulant used, its dose and mass, (ii) pH and initial turbidity of the water which is being treated, and (iii) properties of the pollutants present. The effectiveness of the coagulation process is also affected by pre-treatments like oxidation.
Coagulation bath – It is a liquid-filled tank used in manufacturing, such as wet spinning fibres or casting polymeric membranes, to solidify a liquid polymer solution into a solid form through solvent extraction and precipitation.
Coagulation phenomenon – It is a chemical treatment process used to destabilize and aggregate suspended particles, colloids, and impurities in a liquid. It is most prominently used in environmental and chemical engineering for water and waste-water treatment.
Coagulation time – It is the very short duration, typically lasting only 1 second to 3 seconds (and up to a minute for rapid flash mixing), needed for chemical coagulants to uniformly disperse and neutralize the electrical charges of suspended colloidal particles.
Coal – It is a combustible compact black or brownish black sedimentary rock normally occurring in rock strata in layers or veins called coal beds or coal seams. It is a complex combination of organic matter and inorganic ash formed over eons from successive layers of fallen vegetation. It is composed primarily of carbon along with varying amounts of other elements mainly hydrogen, oxygen, nitrogen and sulphur. It is normally classified for convenience into four categories. These categories are (i) lignite or brown coal, (ii) sub bituminous coal, (iii) bituminous coal, and (iv) anthracite.
Coal ash – It is the mineral matter present in the coal. It is a waste which is left after coal is combusted (burned). It is the particulate material which remains after coal is burned. It includes fly ash (fine powdery particles which are carried up the smoke stack and captured by pollution control devices) as well as coarser materials which fall to the bottom of the furnace. It has different physical and chemical properties depending on the geochemical properties of the coal being used and how that coal is burned.
Coal basin – It is a large geological depression or structural trough in the earth’s crust where layers of coal-bearing sedimentary rock have accumulated and been preserved over millions of years. A coal basin defines the macro-scale boundary for assessing coal reserves, hydro-geological conditions, ground stress, and coal-bed methane (CBM) extraction potential.
Coal-bed methane – It is an unconventional form of natural gas composed mainly of methane (CH4) which is stored through adsorption within the solid matrix and micro-pores of underground coal seams. Unlike conventional natural gas reservoirs where gas accumulates as free gas in large pore spaces under buoyancy, coal-bed methane (CBM) acts as both the source rock and the reservoir rock.
Coal-bed methane (CBM) production – It is the process of extracting unconventional natural gas stored through adsorption within the solid matrix and fracture systems of underground coal seams.
Coal-bed methane (CBM) reservoir – It is an unconventional continuous gas reservoir where natural gas is stored mainly in an adsorbed state on the internal surface area of a micro-porous coal matrix, functioning simultaneously as both the source rock and the reservoir rock.
Coal beneficiation – It is a raw coal preparation process which separates inorganic impurities, ash, and sulphur from mined coal to improve its calorific value and combustion efficiency.
Coal blend – It is a deliberate, calculated mixture of two or more different types, ranks, or grades of coal combined to achieve specific physical, chemical, and economic targets.
Coal blending – It is the process of mixing two or more coal types to optimize cost and quality, allowing for the reduction of overall expenses while meeting the needed specifications. This technique also aims to improve fuel efficiency and minimize issues related to coal quality, such as fouling and emissions.
Coal bottom ash – It is coarse, heavy, and incombustible by-product collected from the bottom of furnaces in coal-fired power plants.
Coal bunker – It is a large storage vessel or silo used in industrial facilities, power plants, and mines to hold a steady supply of raw coal before it is fed into boilers or pulverizers.
Coal carbonization process – It is the process which takes place on coke ovens where the transformation of coal to coke starts taking place. The heat is transferred from the heated brick walls into the coal charge. From about 375 deg C to 475 deg C, the coal decomposes to form plastic layers near each wall. At around 475 deg C to 600 deg C, there is a marked evolution of tar, and aromatic hydrocarbon compounds, followed by re-solidification of the plastic mass into semi-coke. At 600 deg C to 1,100 deg C, the coke stabilization phase begins. This is characterized by contraction of coke mass, structural development of coke and final hydrogen evolution. During the plastic stage, the plastic layers move from each wall towards the centre of the oven trapping the liberated gas and creating in gas pressure build up which is transferred to the heating wall. Once, the plastic layers have met at the centre of the oven, the entire mass has been carbonized. The incandescent coke mass is pushed from the oven and is wet or dry quenched.
Coal characteristics – These characteristics refer to the specific properties of coal, such as heating value, rank, ash content, and moisture content, which influence its suitability for power generation, including tendencies to form slag and fouling deposits during combustion.
Coal charging car – It is used to charge coal blend into the coke oven by means of traditional devices of gravitation type charging or forced charging of coal by screw or rotary feeders. The coal charging car is designed for single spot operation and equipped with the technologies related to pollution control, and safe and efficient operations. The main operations performed by the coal charging car include (i) collection of coal blend from coal tower gates, (ii) travelling over battery top and charging of coal blend into the coke oven, (iii) extraction / installation of lids of charging hatches, (iv) control of stand-pipes and injection valves, and (v) cleaning of elbows and wells of stand-pipes. The main functional units of the charging car are (i) travel drives (bogies), (ii) charging weighing hoppers, (iii) lid cleaners, (iv) frame cleaners, (v) screw feeders (or rotary feeders) for controlled charging, (vi) rotary gates, (vii) sealed telescopes, (viii) lid lifters, (ix) auxiliary lid lifters at coke oven N+2 (the oven charged by the machine during previous sequence), (x) lid luting system, and (xi) oven top vacuum cleaner.
Coal chemicals -These are the chemicals which are produced as by-products in the process of the ‘destructive distillation’ of various blends of bituminous coal.
Coal combustion – It is the rapid exothermic (heat-releasing) chemical reaction between the combustible elements of coal (carbon, hydrogen, and sulphur) and oxygen, converting stored chemical energy into thermal energy to generate high-pressure steam for power production and industrial processes.
Coal composition – It is a heterogeneous mixture of organic maceral compounds and inorganic mineral matter whose proportions determine its combustibility and fuel value, showing diversity not only among coals from different regions but also within coals from the same region.
Coal density – It is the mass of coal per unit volume (d = m/V), typically expressed in kilograms per cubic-meter or grams per cubic centimeter.
Coal deposit – It is a localized, economically recoverable accumulation of combustible, carbon-rich sedimentary rock formed from prehistoric plant remains which has been buried, compressed, and chemically altered over millions of years.
Coal-derived carbon materials – These are high-value carbon products produced from coal, coal by-products (like coal tar pitch), or processed coal precursors instead of burning them for fuel. These materials are solid carbon structures created through thermal, chemical, or molecular processing, such as pyrolysis, carbonization, or gasification, of coal. They feature controllable micro-structures, high surface areas, abundant pore sizes, and tunable electronic properties or graphitization degrees.
Coal energy – It is the usable power extracted by burning coal, a combustible, carbon-rich sedimentary rock formed from ancient plant remains, to convert stored chemical energy into heat, mechanical power, and electricity.
Coalescence – It is the union of particles of a dispersed phase into larger units, normally effected at temperatures below the fusion point. It is also the growing together or growth into one body of the materials being welded. It also means growth of grains at the expense of the remainder by absorption or the growth of a phase or particle at the expense of the remainder by absorption or reprecipitation.
Coalescence risk – It refers to the probability and impact of independent components, systems, or risk factors merging together to create a single, much larger failure. Instead of managing small, isolated issues, engineers face a compounding crisis where boundaries fail and problems combine.
Coalescing filter – It is a device designed to remove sub-micron liquid aerosols and fine droplets from gas or liquid streams by forcing them to merge into larger, heavier drops which drain away.
Coal explosibility – Explosibility of coals is determined by measuring the length of flame when the dry pulverized coal of one gram with size under 0. 074 millimeters is injected to a fire source at 1,050 deg C. If there is no flame near the fire source then the coal has no explosibility. If the length of flashback in glass tube is less than 400 millimeters, then the coal is combustible and explosive, otherwise the coal has strong explosibility.
Coal-fired boiler – It is an industrial or utility energy conversion device which burns coal to transform water into high-pressure and high-temperature steam.
Coal gasification – It is a thermo-chemical process which converts solid coal into a gaseous mixture called synthesis gas, or syngas (mainly carbon mono-oxide, hydrogen, carbon di-oxide, and methane) by reacting it with controlled quantities of oxygen and steam at high temperatures and pressures.
Coal gasification process – It is based on the fundamental principle of partial combustion of coal. The gas which comes out after partial combustion is called raw syngas which is purified further in processing units before it is used. Coal gasification is carried out with limited quantity of oxygen which is around one-fifth to one-third of the theoretically oxygen needed for complete combustion. Only a fraction of carbon is burned for generation of heat. Hydrogen and carbon mono-oxide are the main products of gasification. Methane and carbon di-oxide are other two major products and their content goes up with increasing pressure with hydrogen and carbon mono-oxide content going down. In coal gasifiers two physico-chemical processes take place. They are (i) pyrolysis or devolatilization process, and (ii) gasification process. In the pyrolysis process, as the coal enters into the gasifier, it is first dried by the hot gases present in the gasifier. A series of complex physical and chemical process start slowly at temperature less than 350 deg C and accelerate as temperature exceeds 700 deg C. The composition of the released products of pyrolysis is dependent on the temperature, pressure and gas composition during pyrolysis. The pyrolysis process can be represented by the reaction Coal –> Heat –> Char –> Gases –> Vapours or liquid. The three products which are produced by pyrolysis are (i) light gases such as hydrogen, carbon mono-oxide, methane, carbon di-oxide, water vapour, (ii) tar which is a corrosive and viscous liquid composed of heavy inorganic and organic molecules, and (iii) char which is a solid residue mainly contains carbon. The gasification process involves a series of endothermic reactions which are supported by the heat produced from the combustion reactions occurring inside the gasifier. These reactions are represented by the equations (i) C + O2 = CO2 with delta H = -94.05 kcal/mol, and (ii) H2 + 0.5 O2 = H2O with delta H = – 68.3 kcal/mol. The major gasification reactions which take place are (i) water gas shift reaction, (ii) Boudouard reaction, (iii) shift conversion, and (iv) methanation.
Coal gasification technology – It is a process which converts coal into synthesis gas (syngas), a mixture of carbon mono-oxide, hydrogen, and carbon di-oxide, by reacting coal with oxygen, steam, and / or carbon di-oxide in a high-pressure gasifier at high temperatures. This technology is increasingly utilized for hydrogen production.
Coal generation – It is the process of producing electricity by burning coal to convert chemical energy into electrical energy through a steam-electric Rankine cycle.
Coal geology – It is the study of coal-bearing rock formations, their physical and chemical properties, and their structural distribution to safely and efficiently extract resources and design underground or surface infrastructure.
Coal grinder – It is a heavy mechanical device which crushes and grinds raw coal into a fine, combustible powder.
Coal handling and storage yard – It is a designated industrial facility where raw coal delivered from mines is unloaded, temporarily stored, blended, and managed before being fed into a power plant or industrial boiler.
Coalification – It is the metamorphic processes of forming coal.
Coal liquefaction – It is the process of converting finely crushed coal into liquid hydrocarbon distillate products by increasing its hydrogen-to-carbon ratio, typically for use as transportation fuels or chemicals, through heating in the presence of hydrogen gas and a catalyst under high pressure.
Coal macerals – These are the microscopic, organic building blocks of coal, comparable to how mineral grains form inorganic rocks. In coal petrography, they are distinguished by their shape, structure, and optical properties under a microscope. The maceral analysis is used to predict how coal is going to behave during processing, combustion, gasification, and coking.
Coal measures – These refer to a series of sedimentary rock strata which contain interstratified beds or seams of coal along with associated rocks like shales, mudstones, sandstones, and siltstones. Coal measures are geological formations which contain coal deposits and are characterized by strong heterogeneity, influencing properties such as permeability, which is important for coal mine gas extraction and coal-bed methane production.
Coal metamorphism – It is the process where the physical and chemical properties of coal change because of the rising heat and pressure over time.
Coal mill – It is a heavy mechanical device used to crush and grind raw coal into a fine, combustible dust before it is fed into a boiler furnace.
Coal mine – It is a planned excavation system designed to safely and efficiently extract solid combustible coal seams from the earth using surface or underground methods.
Coal minerals – These minerals refer to the inorganic, crystalline chemical compounds present within coal, distinct from the organic plant matter (macerals) which makes up the bulk of the coal matrix. These minerals are critical since they dictate how coal behaves during extraction, processing, and combustion.
Coal mining – It is the technical process of planning, excavating, and extracting solid combustible coal deposits from the Earth safely and economically.
Coal mixing ratio – It is the proportional mass fraction of different coal types (such as blending high-rank and low-rank or lignite coals) combined to optimize combustion efficiency, boiler stability, and fuel economy in a power plant.
Coal moisture – It is the total quantity of water present in a coal sample, normally defined as the percentage of mass lost when the coal is heated in an oven at 105 deg C to 110 deg C.
Coal moisture analyzer – A number of moisture measurement systems are available. However, the reliable method to measure the coal moisture on-line is to use ‘microwave with area weight compensation’. Microwaves are a highly accurate way to measure moisture due to the fact that microwaves are highly selective to water. They penetrate the material to be measured. Water molecules are naturally polar which causes the microwaves to weaken and slow down considerably.
Coal-oil mixture – It is an alternative liquid fuel made from a suspension of finely pulverized solid coal particles mixed into a liquid petroleum residual fuel oil.
Coal particle – It is a discrete, porous fragment of carbonized organic matter characterized by a complex internal pore structure (macro-pores, meso-pores, and micro-pores) and an irregular 3D shape, categorized by size for combustion, gasification, or fluidization processes.
Coal petrology – It is the microscopic and macroscopic study of coal’s organic and inorganic components to predict its physical behaviour during mining, combustion, and metallurgical processing.
Coal preparation – It is the processing of raw, run-of-mine (ROM) coal through physical and surface separation techniques to remove impurities, regulate particle size, and produce a uniform, market-ready product.
Coal properties – These are the physical, chemical, and thermal characteristics which define how coal behaves during handling, storage, processing, and combustion. These properties are measured to design safe boilers, plan power plant operations, and select the right grade of fuel for steel production or electricity generation.
Coal pulverizer – It is a heavy mechanical device used in thermal power plants to grind raw, crushed coal into a fine, talcum-powder-like dust before it is blown into a boiler furnace for combustion.
Coal pyrolysis – It is the thermal decomposition of coal at high temperatures (typically 400 deg C to 900 deg C) in the complete absence of oxygen, converting complex macro-molecular structures into solid char, condensable liquids (tar), and combustible gases. Since no oxygen or steam is present, the coal does not burn. Instead, the thermal energy breaks weak chemical bonds (like aliphatic bridges) within the coal’s molecular structure, driving off volatile matter and leaving behind a carbon-enriched solid.
Coal rank – Coals are classified by rank according to their progressive alteration in the natural metamorphosis from lignite to sub bituminous coal to bituminous coal and to anthracite. Ranking is determined by the degree of transformation of the original plant material to carbon. Coal rank depends on the volatile matter, fixed carbon, inherent moisture, and oxygen, although no one parameter defines rank. Typically coal rank increases as the amount of fixed carbon increases and the amount of volatile matter decreases.
Coal ratio – It is the mass of pulverized coal injected into the blast furnace per ton of hot metal produced (frequently expressed as kilograms per ton of hot metal, serving as a key metric for auxiliary fuel consumption. In coal processing / feedstock analysis, it can denote the relative mass or processing capacity ratio between different carbon feeds, such as coking coal against gasification coal.
Coal reactivity – It is the rate at which coal undergoes a chemical conversion or reaction (such as combustion, gasification, or pyrolysis) when exposed to a reactive gas like oxygen, steam, or carbon di-oxide under specific temperature and pressure conditions.
Coal research -It is the scientific and technical study of extracting, characterizing, converting, and utilizing coal while minimizing its environmental impact.
Coal reservoir – It is a dual-porosity geological formation comprising a coal matrix which stores gas mainly through adsorption, and a natural network of fractures (cleats and fissures) which allows fluid and gas to flow. Unlike conventional gas reservoirs where hydro-carbons migrate from a separate source rock, a coal seam acts as the source rock, the storage reservoir, and the production zone simultaneously for coal-bed methane (CBM).
Coal resource – It is the total estimated quantity of coal in a given deposit or in the earth’s crust, assessed through geological data and direct measurements before accounting for economic or legal mining feasibility.
Coal sample – It is a small, statistically representative quantity of coal collected from a larger bulk lot (such as a seam, stockpile, or railway wagon) and used to assess its physical, chemical, and petrographic properties.
Coal seam – It is a distinct, underground stratum or bed of coal which is thick and stable enough to be commercially and profitably mined.
Coal selection – It is the systematic process of evaluating, testing, and choosing specific coal sources which match a combustion facility’s boiler design, environmental limits, and operational goals.
Coal silo – It is a large, vertical, cylindrical storage structure designed to safely receive, buffer, discharge, and manage bulk quantities of raw, crushed, or processed coal.
Coal strength – It is the measure of a coal sample’s capacity to withstand applied mechanical stress before fracturing or failing.
Coal structure – It refers to the internal macroscopic and microscopic makeup of coal, including its macro-molecular chemical arrangement, fracture networks, pore systems, and degree of geological deformation.
Coal tar – It is a by-product generated during the high temperature carbonizing of coking coal for the production of the metallurgical coke in the by-product coke ovens. It is a black, viscous, sometimes semi-solid, fluid of peculiar smell, which is condensed together with aqueous ‘gas-liquor’ (ammoniacal liquor), when the volatile products of the carbonization of coking coal are cooled down. Composition is variable, but normally consists of 0 % to 2 % of light oils (chiefly benzene, toluene, and xylene), 16 % to 18 % of middle oils (chiefly phenols, cresols, and naphthalene), 8 % to 10 % heavy oils (naphthalene and derivatives), 16 % to 20 % anthracene oils, and around 50 % pitch. It is composed primarily of a complex mixture of condensed-ring aromatic hydrocarbons. It can contain phenolic compounds, aromatic nitrogen bases and their alkyl derivatives, and paraffinic and olefinic hydrocarbons.
Coal tar distillation process – Fractional distillation process is used for the distillation of coal tar. Fractional distillation of tar refers to the process by which components in a chemical mixture are separated by taking advantage of the difference in their boiling points. Distillation of coal tar is carried out mainly to produce benzole, naphtha, creosotes, naphthalene, anthracene, carbolic and cresylic acids, pyridine and pitch. The purpose of tar distillation is to (i) dehydrate the tar in the dehydration column, (ii) remove the pitch from dehydrated tar in pitch column and (iii) separate tar oils in fractionating column. Since the quality of the coal tar is dependent on the coal carbonizing process and since there are large numbers of chemical compounds available in coal tar, the design and composition of the tar distillation plant varies with the type of tar and the compounds which are required to be distilled. Hence, it is very rare that the two tar distillation plants are exactly similar.
Coal tar pitch – It is a dark-brown-black, shiny, amorphous residue produced during the distillation of coal tars. It is composed of many different compounds which interact to form eutectic mixtures and thus it does not show a distinct melting or crystallization point. Rather, it is characterized by a softening point (the temperature at which a given viscosity is reached). Depending upon the extent of distillation, pitches of different softening point can be obtained. Examples are medium soft pitch or very hard pitch. It is the preferred material for use as a binder in the manufacture of carbon and graphite electrodes.
Coal-to-liquids – It refers to the conversion of coal into liquid fuels through processes such as the Fischer-Tropsch synthesis or hydrogenation, producing alternatives like diesel, naphtha, and LNG (liquefied natural gas) This method allows countries with large coal reserves to reduce reliance on imported petroleum, although it faces challenges related to green-house gas emissions and resource use.
Coal-to-liquids (CTL) technology – It converts solid coal into clean synthetic liquid fuels, such as gasoline and diesel, by increasing the material’s hydrogen-to-carbon ratio.
Coal type – It defines a combustible sedimentary rock classified by its maturity, physical appearance, and degree of organic alteration, known as coal rank, resulting from plant decomposition under intense heat and pressure over millions of years.
Coal utilization – It refers to the methods and processes used to extract, process, and convert coal into thermal energy, electrical power, metallurgical coke, and chemical feedstocks. Four main thermal and chemical transformation processes are combustion, carbonization, gasification, and liquefaction.
Coal-water fuel – It is a fluid mixture made of finely pulverized coal particles suspended in water, combined with small quantities of chemical additives like surfactants and stabilizers.
Coal-water mixture – It is a fluid alternative fuel made by mixing finely ground pulverized coal with water and chemical additives.
Coal water slurry – It is a mixture of fine coal particles suspended in water, used as a liquid fuel in place of traditional fuels like oil and gas in power plants and combustion systems.
Coal water slurry fuel – It is a liquid substitute for oil and gas made from fine coal particles mixed with water and chemical additives.
Coal yard – It is a designated outdoor or enclosed industrial storage area at a power plant or manufacturing facility where bulk coal is unloaded, temporarily stockpiled, blended, and prepared.
Coanda effect – It is the physical tendency of a fluid jet (air or liquid) to adhere to a nearby curved or flat surface and follow its contour rather than continuing in a straight line.
Coarse ash – It refers to larger particles of ash, typically higher than 150 micro-meters, which can contain a substantial proportion of the total carbon present in fly ash, frequently up to 50 %. These particles can be effectively separated from finer ash particles using size classification techniques.
Coarse fly ash – It refers to the larger, heavier fraction of fly ash particles, typically higher than 150 micro-meters, which are captured from coal-fired power plant emissions, possessing lower pozzolanic reactivity and higher unburnt carbon content compared to finer fly ash.
Coarse-grained molecular dynamics – It is a computational simulation method which groups multiple atoms or molecules into single ‘beads’ or interaction sites to reduce system complexity and accelerate calculations. Coarse-grained molecular dynamics (CGM)D bridges the gap between atomic-scale molecular dynamics and macroscopic continuum models. It allows people to simulate larger systems (meso-scale) over much longer time scales than traditional all-atom models permit.
Coarse grain heat affected zone – It is a region within the heat affected zone (HAZ) which experiences high temperatures and significant grain growth during welding. It is characterized by larger grain sizes and can have detrimental effects on the mechanical properties of the welded joint.
Coarse grains – These are grains larger than normal for the particular wrought metal or alloy or of a size which produces a surface roughening known as orange peel or alligator skin.
Coarse-grain zone – It refers to the region within a material’s micro-structure, such as the heat-affected zone (HAZ) in welding or an extruded metal profile, where high temperatures cause individual crystal grains to grow considerably larger than those in the surrounding base material.
Coarse grid – It is a simplified, lower-resolution discretization mesh with fewer grid points or cells used to approximate governing equations across a physical domain.
Coarse mesh – It is a discretization grid made of relatively large elements or cells which cover a geometric domain, offering fast computation times at the expense of high spatial resolution and precision.
Coarse mesh model – It is a computer simulation set-up which uses large elements to divide a shape, which saves computer power but lowers detail accuracy. In computer-aided engineering (CAE), finite element analysis (FEA), and computational fluid dynamics (CFD), continuous physical spaces are broken down into a grid of smaller geometric shapes called elements.
Coarsening – It is an increase in grain size, normally, but not necessarily, by grain growth.
Coarse pearlite – It is the pearlite for which the alternating ferrite and cementite layers are relatively thick. This is achieved by very large preceding austentite grains and / or long holding times in the upper pearlite regime e.g. during the patenting treatment.
Coarse pitch – It is the roller centre spacing, which measures 37 millimeters, or 28 shafts per meter.
Coarse sand – It is a fine aggregate with particle sizes typically ranging from 2 millimeters to 4.75 millimeters (retained below the No. 4 sieve and passing standard smaller sieves).
Coarsest sieve -It the top screen in a sieve analysis stack which has the largest opening size and receives the initial raw material sample.
Coastal area – It is the dynamic interface zone where land and water meet, encompassing both the land and sea areas influenced by marine processes (like waves, tides, and storm surges) and terrestrial factors.
Coastal zone – It is the dynamic interface area where land and water meet, encompassing the land affected by its proximity to the sea and the marine waters influenced by terrestrial activities.
Coasting distance – It is the distance a conveyor system continues to move after the power is turned off, needing consideration for safety and operational planning.
Coated abrasive – It an abrasive product (sand-paper, for example) in which a layer of abrasive particles is firmly attached to a paper, cloth, or fibre backing by means of glue or synthetic-resin adhesive.
Coated abrasive product – It is a two-body abrasion device in which a backing paper or cloth is coated with a layer of abrasive grits, which are cemented to the backing.
Coated cold rolled flat products – These are the flat products with a permanent coating. The permanent coatings can be either on both sides or only on one side. In case of coating on both the sides, it can be either equal thickness coating on each side or of different thickness of coating on each side known as differential coating.
Coated drills – These drills refer to drill bits which are covered with high-performance materials to improve their durability and reduce wear during drilling operations. These coatings, such as TiN (titanium nitride), TiAlN (titanium aluminum nitride), and diamond, improve tool life and the quality of produced holes by minimizing friction and abrasion compared to uncoated drill bits.
Coated electrode – A composite filler metal electrode consisting of a core of a bare electrode or metal cored electrode to which a covering sufficient to provide a slag layer on the weld metal has been applied. The covering can contain materials providing such functions as shielding from the atmosphere, deoxidation, and arc stabilization and can serve as a source of metallic additions to the weld. The preferred terms for coated electrode are covered electrode and lightly coated electrode.
Coated film – It is a precisely applied, thin layer of material, ranging from nano-meters to micro-meters thick, bonded to a substrate or core to modify its surface properties.
Coated plate – It is a structural or functional plate component, typically made of metal like steel or aluminum, which has a specialized layer of metallic, organic, or ceramic material bonded to its surface to improve properties such as corrosion resistance, wear protection, or thermal insulation.
Coated rebars – These are standard carbon-steel reinforcement bars covered with a protective layer, very frequently a fusion-bonded epoxy, to act as a physical and electro-chemical barrier against corrosion. These reinforcement steel bars are treated with a protective polymer coating (typically 175 micro-meters to 300 micro-meters thick).
Coated tool – It is a cutting or machining tool covered with one or more thin, hard, and chemically stable layers (typically a few micrometers thick) to improve its performance.
Coating – It is a relatively thin layer (less than 1 millimeter) of material applied by surfacing for the purpose of corrosion prevention, resistance to high-temperature scaling, wear resistance, lubrication, or other purposes.
Coating, anode – Anode coating is the application of a protective or functional layer, such as carbon, polymers, or metal oxides, onto an anode’s surface to prevent corrosion, manage interfacial resistance, and improve overall electro-chemical performance.
Coating application – It is the controlled process of depositing a thin layer of protective, functional, or decorative material onto a substrate surface to improve performance, prevent wear, and stop corrosion without changing the bulk material’s core properties.
Coating break-down – It refers to the gradual failure, degradation, or loss of protective and electrical-insulating properties of a protective coating applied to an underlying substrate (normally metal). It measures how much a coating system loses its ability to block corrosive elements (like moisture, oxygen, and salts) or act as an electrical barrier.
Coating break-down factor – It is a value used to calculate how much an electrically insulating protective coating reduces the current needed for a cathodic protection system over time. Coating break-down factor describes the extent of current density reduction because of the application of coating.
Coating blister – it is a raised area, frequently dome shaped, resulting from loss of adhesion between a coating or deposit and the substrate.
Coating build-up – It is the accumulated thickness of a paint, polymer, plating, or surface finish on a substrate, or an excess thickness caused by overlapping or uneven application.
Coating, conversion – It is an inorganic pretreatment sometimes applied to a metal surface to improve coating adhesion and to retard corrosion.
Coating cost – It is the total economic expense needed to prepare a substrate, apply a protective or functional material layer, and finish the surface.
Coating density – It is a non-standard term for spray deposit density ratio which is the ratio of the density of the spray deposit to the theoretical density of a surfacing material, normally expressed as a percent of theoretical density.
Coating deposition – It is the process of applying a thin or thick layer of material atom-by-atom, molecule-by-molecule, or in bulk onto a base object (called a substrate) to change its surface properties.
Coating drip – It is a nonuniform extraneous deposit of coating on the coated sheet.
Coating formation – It is the process by which a distinct, continuous layer of material (the coating) is deposited, transformed, or grown onto a base object (the substrate) to modify its surface properties.
Coating hardness – It is a measure of a surface layer’s resistance to permanent plastic deformation, scratching, or penetration caused by external mechanical forces.
Coating, high or low – It means failure of the coating to meet the agreed-upon thickness limits measured in weight per unit area.
Coating, liquid – Liquid coating is a process which involves applying coatings based on aqueous or organic solvents, or solvent-less systems which utilize 100 % solids, to flexible materials. This process includes stages such as coating application, drying or curing, and is typically conducted using roll-to-roll coating lines.
Coating mass – Galvanized coatings are normally specified in terms of coating mass, in grams per square metre, on the surface of the steel. For ease of measurement, the thickness of a galvanized coating is measured in micro-meters using non-destructive techniques. One micrometer in thickness is around 7 grams per square metre in coating mass.
Coating material – It is a substance applied in liquid, paste, powder, or vapour form to a base surface (called a substrate) which hardens into a continuous, thin film to alter or improve surface properties.
Coating oven trash – It is also normally referred to as oven dirt or bittiness. It is an airborne particulate matter or debris inside a curing oven which settles onto a wet or melting coating, creating a visible surface defect. It transforms a smooth finish into a rough, ‘pitted’, or bumpy surface, frequently forcing manufacturers to scrap or rework the affected parts.
Coating performance – It is the measure of how well a surface layer protects, decorates, or provides specific functional properties to a substrate under designated environmental and mechanical operating conditions. Unlike standard paint, which mainly focuses on aesthetics and colour, a coating is a performance-driven material system designed to alter surface reactions without changing the bulk material’s internal properties.
Coating process – It is the method of applying a thin layer of material onto a surface (substrate) to improve its appearance, durability, or performance. Majority of the coating processes follow three basic stages namely surface preparation, application, and curing or drying.
Coating quality – It is the measure of how well a deposited surface layer meets specified physical, chemical, and functional requirements to protect or improve a substrate.
Coating, refractory – It consists of unshaped refractory consisting of a mixture of fine aggregate and bond, supplied for use with a higher water or other liquid content than a jointing material. The principle bond can be ceramic, hydraulic, chemical, or organic. The mixture is applied manually (with a brush or trowel), by pneumatic or mechanical projection, by spraying or dipping. Other types of coating can be applied to refractory components by specialized techniques (e.g., flame or plasma spraying) but these are normally considered as advanced technical ceramic materials rather than refractories.
Coating separation – It refers to the physical detachment of a protective or decorative layer from its underlying substrate or from another coating layer. It represents a failure of adhesion or cohesion within a material system.
Coating streak – It is a continuous or intermittent linear defect running in the machine direction (down-web) which results in a localized variation in coating thickness, texture, colour, or gloss. Unlike broad flow instabilities, streaks are localized fluid flow disturbances which typically occur when a foreign particle or mechanical imperfection alters the path of the wet fluid, which is then cured permanently into the final product.
Coating strength – It is a measure of the cohesive bond within a coating, as opposed to coating-to-coating substrate bond. It is the tensile strength of a coating.
Coating stress – It is the stresses in a coating resulting, e.g., from rapid cooling of molten or semi-molten particles as they impact the substrate or from differential thermal expansion.
Coating structure – It refers to the specific arrangement, layering, and microscopic composition of a deposited protective, functional, or decorative film on a base material (substrate).
Coating surface – It is the outer layer formed when a thin, continuous substance is applied to a base material (substrate) to change its properties without altering its internal composition.
Coating system – It is a structured combination of multiple compatible layers, such as a primer, intermediate coat, and top-coat, applied in sequence to a prepared surface (substrate) to protect it from corrosion, wear, and environmental damage.
Coating technique – It is a specialized process used to apply a thin, uniform layer of liquid, gas, or solid material onto a substrate surface to enhance its protective, functional, or decorative properties.
Coating thickness – It is the thickness of the zinc coating, measured in micrometers. The hot dip galvanized coating thickness is determined by galvanizing bath chemistry, steel chemistry, steel surface condition, and steel section thickness. National standards normally define minimum acceptable coating thickness for a range of steel sections.
Coating types – Coatings are of two types namely organic coatings and inorganic coatings. Coatings are also classified by purpose into three categories namely protective (corrosion and wear resistance), decorative (colour and finish), and functional (conductivity, anti-fouling, and similar performance properties). Protective coatings guard against corrosion, biological fouling, and fire. Anti-corrosion systems on structural steel are the most common example. Decorative coatings include paints, varnishes, and lacquers chosen for gloss, satin, or matte finishes. Functional or specialty coatings solve a specific engineering problem. Examples are non-stick coatings, anti-microbial coatings, and electrically conductive coatings.
Coating, window – Window coatings are thin films applied to glass surfaces which possess spectrally selective properties, enabling the regulation of radiant energy and improving energy efficiency by blocking infrared radiation and facilitating heat retention. These coatings include different types such as photochromic, thermochromic, electrochromic, and suspended particle devices.
Coaxial cable – It is a specialized electrical transmission line with a concentric, multi-layer structure designed to carry high-frequency radio frequency (RF) signals with minimal loss and high immunity to electro-magnetic interference (EMI). A standard coaxial cable consists of four main concentric layers sharing the same geometric axis. These layers are centre conductor, dielectric insulator, metallic shield, and outer jacket.
Coaxial cylinder viscometer – It is a laboratory instrument which measures a fluid’s viscosity by shearing it within the narrow gap between two concentric cylinders.
Coaxial distribution – It is a network system which uses coaxial cables, amplifiers, and passive radio frequency (RF) components to send signals, such as cable television or broadband data, across specific upstream and downstream band-widths while keeping signal loss very low.
Coaxial electro-spinning – It is an advanced engineering fabrication technique which uses two or more concentric, parallel nozzles to simultaneously eject distinct liquid solutions into a high-voltage electro-static field, creating composite nano-fibres with a core-shell or hollow structure.
Coaxiality – It is a geometric tolerance which specifies how closely the centre axis of a cylindrical or tubular feature is to align with a designated reference (datum) axis. It controls the allowable deviation of a feature’s 3D centre axis so that it remains collinear with a reference axis.
Coaxial network – It is a communication system which uses coaxial cable to transmit high-frequency electrical signals with strong resistance to outside interference.
Coaxial nozzle – It is a fluid-delivery or extrusion device featuring two or more concentric, nested channels which discharge a central (core) stream surrounded by one or more outer (sheath or annular) streams.
Coaxial set-up – It refers to an arrangement where two or more cylindrical conductors, shields, or components share the same geometric central axis.
Coaxial solenoid valve – It is a direct-acting solenoid valve with an unobstructed flow route for very viscous media or high-pressure applications.
Coaxial structure – It is a geometric and physical arrangement where two or more cylindrical conductors, shields, or elements share the exact same geometric centre axis.
Coaxial tube – It is an arrangement of two concentric tubes where one smaller tube is nested inside a larger outer shell, sharing the same geometric axis.
Coaxial valve – It works by utilizing an internal, axially movable hollow tube, which can either control or divert the flow of media passing through the valve. Coaxial valves are valves known for fast switching times combined with high working pressures and are used to control the flow of liquids or gases. The valves are ideal for high viscosity media.
Coaxing – It is improvement of the fatigue strength of a sample by the application of a gradually increasing stress amplitude, normally starting below the fatigue limit.
Cobalt – Cobalt (atomic number 27 and atomic weight 58.94) has density of 8.85 grams per cubic centimeter. Its melting point is 1493 deg C and boiling point is 3100 deg C. It increases strength and hardness, and permits quenching at higher temperatures. In some steels used for nuclear engineering, cobalt is an undesirable impurity, even in quantities as low as 0·02 %. Unlike most other alloying elements, cobalt reduces hardenability. It raises the red hardness of the steel and this is the reason 5 % to 10 % of cobalt is added to certain types of high-speed steels, developed for the specific purpose of cutting exceptionally hard materials. Heat resisting alloys with high cobalt contents have been developed for use in gas turbines. Cobalt is added to the extent of up to 40 % to magnet steels requiring high coercive force and it is used in electrical- resistance alloys. In the sintered hard metals cobalt acts as the binding metal.
Cobalt-60 – It is a man-made radio-active metal which gives off high-energy gamma rays. It has a half-life of about 5.3 years. People make it in nuclear reactors by using regular cobalt.
Cobalt Acetylacetonate – It is normally abbreviated as Co(acac)2 for the cobalt(II) form or Co(acac)3 for the cobalt(III) form. It is a volatile, metal-organic coordination complex utilized mainly as a chemical precursor for thin-film deposition, nano-material synthesis, and industrial catalysis. It features a central cobalt cation chelated by bidentate acetylacetonate ligands, rendering the complex highly stable, hydrophobic, and soluble in organic solvents. Cobalt acetylacetonate is selected because of its clean thermal decomposition pathway and excellent solubility profile.
Cobalt alloys – These are metal mixtures where cobalt serves as the main base element, combined with elements like chromium, tungsten, molybdenum, nickel, and carbon.
Cobalt ammonium sulphate – It is specifically ammonium cobalt(II) sulphate hexa-hydrate. It is a double salt belonging to the Tutton’s salt family. It is used as a high-purity chemical precursor and crystal component. Its chemical formula is (NH4)2Co(SO4)2. 6H₂O. Its structure is monoclinic double-sulphate crystal containing dual cations (Co2+ and NH4+). It has appearance of ruby-red or pink crystalline solid.
Cobalt-base alloys – These are engineering materials made mostly of cobalt mixed with other elements like chromium, tungsten, and nickel to handle extreme heat, wear, and corrosion. Cobalt makes up the largest percentage of the alloy.
Cobalt-base corrosion-resistant alloys – These alloys represent a critical class of high-performance materials engineered to withstand aggressive environments while maintaining exceptional wear resistance and mechanical integrity. These alloys, typically contain chromium, molybdenum, tungsten, and other strategic alloying elements. These alloys contain 17 % to 30 % chromium, and 8 % to 30 % molybdenum.
Cobalt-base hard-facing alloys – These are specialized non-ferrous overlay materials, welded onto cheaper base metals to provide exceptional resistance to wear, galling, corrosion, and extreme heat.
Cobalt-base heat-resistant alloys – These are a class of advanced superalloys mainly composed of cobalt combined with chromium, tungsten, and nickel, engineered to maintain structural integrity, strength, and resistance to oxidation and thermal fatigue at extreme temperatures (frequently exceeding 800 deg C).
Cobalt-base high-temperature alloys – These are specialized superalloys engineered to maintain mechanical strength, structural integrity, and resistance to degradation at extreme temperatures (frequently exceeding 500 deg C up to 1,000 deg C plus).
Cobalt-base superalloys – These are high-performance metallic materials with cobalt as the main matrix element, engineered to maintain structural integrity, strength, and resistance to wear, corrosion, and thermal fatigue at extreme temperatures.
Cobalt-base wear-resistant alloys – These are engineering metallic materials composed mainly of cobalt (over 50 % or down to roughly 30 %) combined with chromium, tungsten, or molybdenum, and carbon, designed to withstand severe sliding, abrasive, and erosive wear.
Cobalt-carbon (Co-C) binary phase diagram – It is a thermodynamic map which plots temperature versus composition (at a constant pressure of 0.1 megapascal) for a two-component system consisting purely of Cobalt (Co) and carbon (C). It defines the boundaries of phase stability, phase transformations, and chemical solubility limit ranges under equilibrium cooling conditions. This system is structurally similar to the fundamental Iron-carbon (Fe-C) system but is heavily utilized in specialized industries, particularly in engineering cemented carbides (hard metals) such as tungsten carbide-cobalt (WC-Co) cutting tools and wear-resistant coatings.
Cobalt chloride – It is an inorganic chemical compound which functions as a color-changing moisture indicator, catalyst, and electro-plating additive in engineering and industrial applications. Chemical formula for anhydrous cobalt chloride is CoCl2 and for hexahydrate form is CoCl2. Colour of anhydrous form is blue and of hydrated forms turn purple or pink depending on water absorption.
Cobalt-chromium-aluminum-yttrium (CoCrAlY) coating – It is a high-performance metallic overlay or bond coat applied to superalloy components to protect them from extreme oxidation, hot corrosion, and thermal fatigue at elevated temperatures.
Cobalt-chromium (Co-Cr) binary phase diagram – Itis a graphical representation to show the phases, equilibrium states, and chemical compositions of an alloy containing only cobalt and chromium at different temperatures and concentrations under atmospheric pressure. It serves as a roadmap for engineers to predict how the material behaves during melting, solidification, and heat treatment.
Cobalt-chromium-iron isothermal section – An isothermal section of a cobalt-chromium-iron (Co-Cr-Fe) ternary system is a phase diagram which shows the equilibrium phases of the alloy at a single, constant temperature. It is a map used to predict the microstructure and phase stability of these alloys, which are critical for high-temperature and wear-resistant applications.
Cobalt-chromium-iron (Co-Cr-Fe) ternary diagram – It is a triangular phase graph used to map out the phases, structural transitions, and equilibrium states of an alloy system containing these three metallic elements at different temperatures and compositions. These diagrams are important tools for designing high-performance materials, particularly superalloys, stainless steels, and wear-resistant materials used in industrial tooling.
Cobalt-chromium-nickel isothermal section – An isothermal section of a cobalt-chromium-nickel (Co-Cr-Ni) ternary system is a phase diagram which shows the equilibrium phases present in the alloy at a single, constant temperature.
Cobalt-chromium-nickel (Co-Cr-Ni) ternary diagram – It is a triangular phase graph used to represent the equilibrium phases, solid solutions, and structural boundaries of alloys containing these three transition metals at specific temperatures and pressures. These diagrams are critical for designing superalloys used in extreme environments, such as high-wear industrial components.
Cobalt-chromium-tungsten isothermal section – It is a 2D phase diagram snapshot which shows the stable phases and equilibrium boundaries of the cobalt-chromium-tungsten (Co-Cr-W) alloy system at a single, constant temperature. Since the cobalt-chromium-tungsten system has three components (a ternary system), a full phase diagram needs a 3D coordinate system (composition X, composition Y, and temperature). An isothermal section slices this 3D diagram horizontally at a specific temperature to make it readable in two dimensions.
Cobalt-chromium-tungsten ternary diagram – It is a geometric, three-component phase map which defines the thermodynamic equilibrium, phase stability, and microstructural boundaries of the cobalt-chromium-tungsten (Co-Cr-W) alloy system at different temperatures and chemical compositions. This diagram serves as the foundational metallurgical blueprint for designing Stellite alloys and cobalt-based superalloys used in extreme wear, high-temperature, and corrosive environments.
Cobalt deposits – These deposits refer to natural mineral accumulations containing cobalt, which are typically extracted as co-products or by-products of copper and nickel mining rather than as standalone ores. Cobalt rarely occurs as a native stand-alone element or pure mineral deposit in the earth’s crust. It is chemically combined in oxides, sulphides, arsenides, or substituted into other metal lattices.
Cobalt fluoborate – It is also spelled cobalt fluoroborate. It is a highly soluble chemical compound with the molecular formula Co(BF4), mainly utilized as a specialized electrolyte for cobalt electroplating and electroforming. It acts as a high-performance source of cobalt ions (Co2+) in aqueous solutions. It is favoured over standard sulphate or chloride baths when metallurgical applications need exceptionally high plating speeds and specific physical properties.
Cobalt-free super high-speed steel – It is a high-performance tool steel developed to achieve the exceptional red hardness, wear resistance, and cutting efficiency of traditional ‘super’ high-speed steels without utilizing cobalt as an alloying element.
Cobalt-iron (Co-Fe) binary phase diagram – It is a graphical map which defines the equilibrium phases, structural transformations, and chemical boundaries of alloys containing only cobalt (Co) and iron (Fe) across a range of temperatures and compositions. Since both iron and cobalt are ferro-magnetic transition metals with similar atomic radii, ey show extensive solid solubility. This system is highly celebrated for producing soft magnetic alloys (like Permendur) which possess the highest saturation magnetization of any known binary alloy.
Cobalt-iron-molybdenum isothermal section – An isothermal section of a cobalt-iron-molybdenum (Co-Fe-Mo) system is a ternary phase diagram which shows the equilibrium phases of the alloy at a single, constant temperature. It serves as a visual map defining how these three metallic elements interact, dissolve into one another, or form distinct chemical compounds when held at a specific temperature.
Cobalt-iron-molybdenum (Co-Fe-Mo) ternary diagram – It is a metallurgical phase diagram which graphically represents the equilibrium phases and structural transitions which occur in a three-component alloy system composed of cobalt, iron, and molybdenum at varying temperatures and compositions. These diagrams are necessary for understanding how the three elements interact, dictate the micro-structures of the alloy, and influence mechanical properties like hardness, magnetic strength, and thermal stability.
Cobalt-iron-nickel isothermal section – An isothermal section of the cobalt-iron-nickel (Co-Fe-Ni) system is a phase diagram cross-section which shows the equilibrium phases and structural boundaries of the three metals at a single, constant temperature. Since a full cobalt-iron-nickel (Co-Fe-Ni) system is a ternary (three-component) alloy, its complete phase diagram is a three-dimensional prism. Metallurgists slice this prism horizontally at a specific temperature to create a two-dimensional triangular map (Gibbs triangle).
Cobalt-iron-nickel ternary diagram – It is a three-variable phase graph used ito map the equilibrium phases, crystal structures, and chemical boundaries of alloys composed of these three transition metals at different compositions and temperatures. Since cobalt, iron, and nickel are adjacent to each other on the periodic table, they share similar atomic radii and electronic structures, making their ternary system highly important for engineering specialized magnetic, structural, and high-temperature materials.
Cobalt-iron-tungsten isothermal section – An isothermal section of the cobalt-iron-tungsten (Co-Fe-W) ternary system is a cross-sectional phase diagram which shows the stable phases and equilibrium boundaries of the alloy at a single, constant temperature. Since a ternary system has three components, its full phase diagram is three-dimensional (a triangular prism where the vertical axis represents temperature). An isothermal section cuts horizontally through this prism, providing a 2D map of how varying the concentrations of Cobalt, iron, and tungsten affects the material’s microstructural phases at that specific temperature.
Cobalt-iron-tungsten (Co-Fe-W) ternary diagram – It is a geometric map which represents the phase equilibria, structural transformations, and chemical stability of alloys containing different combinations of cobalt, iron, and tungsten across a range of temperatures. Since it involves three distinct elemental components, this metallurgical system is plotted as a three-dimensional triangular prism where the base is an equilateral triangle representing chemical composition, and the vertical axis dictates temperature. In practice, metallurgists mainly evaluate this system using two-dimensional isothermal sections (horizontal cuts at constant temperatures) and liquidus projections.
Cobaltite – It is a strategically significant mineral composed of cobalt, arsenic, and sulphur (CoAsS) crystallizing in the orthorhombic (or pseudo-cubic) system resembling pyrite. It contains up to 10 % iron and a valuable quantity of nickel. It serves as a commercially and strategically significant primary ore used to extract pure cobalt metal.
Cobalt mine – It is an industrial excavation and processing operation designed to locate, extract, and recover cobalt-bearing mineral ores, which are predominantly produced as a co-product or by-product of large-scale copper and nickel operations.
Cobalt-molybdenum binary phase diagram – It is a graphical map which defines the thermodynamic equilibrium phases, phase boundaries, and structures formed by mixing pure cobalt (Co) and molybdenum (Mo) as a function of temperature and chemical composition at a constant pressure. Understanding this system is necessary since both metals are foundational elements for designing high-performance materials like nickel-base and cobalt-base superalloys, and high-speed tool steels (e.g., Co-Cr-Mo alloys).
Cobalt-molybdenum-nickel isothermal section – It is a specific type of phase diagram which maps out the equilibrium phases and micro-structures of a three-part (ternary) alloy system at a single, constant temperature. Since ternary systems vary by three distinct factors, composition of element 1, composition of element 2, and temperature, visualizing them all at once needs a 3D model (a triangular prism). An isothermal section acts as a 2D horizontal ‘slice’ through that prism.
Cobalt-molybdenum-nickel ternary diagram – It is a triangular phase graph used to represent the equilibrium phases, chemical compositions, and temperature-dependent structures of alloys formed by mixing these three transition metals. These diagrams are necessary for designing superalloys, catalysts, and wear-resistant coatings where precise control over mechanical properties and corrosion resistance is needed.
Cobalt-nickel binary phase diagram – It is a graphical map which shows the stable crystal phases and phase transformations of cobalt and nickel mixtures across different temperatures and chemical compositions.
Cobalt-nickel-chromium-aluminum-yttrium (CoNiCrAlY) coating – It is a high-performance protective overlay used in extreme engineering environments to prevent oxidation, hot corrosion, and thermal degradation. It belongs to the family of MCrAlY coatings, where ‘M’ stands for a metal matrix of nickel, cobalt, or both.
Cobalt ore – It is a naturally occurring rock or mineral accumulation containing a sufficient concentration of cobalt (Co) to make its extraction economically and technologically viable. Cobalt ore is rarely mined as a standalone main commodity. Instead, it is classified and treated as a highly valuable by-product or co-product embedded within larger sediment-hosted copper-cobalt ores or nickel-bearing sulphide and laterite deposits. Since cobalt typically has a low average grade within the raw matrix, frequently ranging from just 0.1 % to 0.5 %, recovering it needs highly specialized mineral processing and metallurgical engineering workflows.
Cobalt plating – It is a surface treatment process which deposits a thin, uniform layer of cobalt or a cobalt alloy onto a metal substrate to improve durability, wear resistance, and corrosion protection.
Cobalt processing – It is the multi-step metallurgical method used to extract, concentrate, and refine raw cobalt-bearing ores or recycled materials into high-purity cobalt metal or chemical compounds. Since raw cobalt ore has no direct industrial use and normally contains low concentrations mixed with other elements like copper, nickel, and iron, processing transforms the raw material into high-purity (frequently higher than 99.8 %) forms needed for advanced technologies.
Cobalt sulphamate – It is an inorganic chemical salt. It is used mainly for high-speed electro-plating and electro-forming to produce smooth, ductile metal layers. Its chemical formula is Co(SO3NH2)2. It is either reddish-brown solid or water-soluble liquid solution. It acts as a source of cobalt ions in electrolytic baths.
Cobalt sulphate (CoSO4) – It refers to a highly water-soluble, reddish-pink inorganic chemical compound which serves as a critical intermediate phase during the extraction, refining, and down-stream processing of cobalt from its raw ores. During the hydro-metallurgical extraction of cobalt (frequently got as a by-product of copper and nickel mining), cobalt sulphate functions as an important transport phase.
Cobalt-tungsten (Co-W) binary phase diagram – It is a thermodynamic blueprint which charts how pure cobalt and pure tungsten interact, mix, or separate into distinct metallurgical phases across different temperatures and chemical concentrations under constant pressure. This diagram is fundamental for cobalt-based superalloys and understanding the foundational chemistry behind cemented carbides (like WC-Co (tungsten carbide–cobalt) or tungsten carbides with a cobalt binder).
Co-based (cobalt-based) coating – It is a hard-facing or protective layer made mainly of cobalt and alloyed with elements like chromium, tungsten, nickel, or carbon, applied to a metal substrate to improve resistance to wear, high-temperature oxidation, and corrosion.
Cobb-Douglas production function – It is a mathematical equation which models the relationship between physical inputs (normally capital and labour) and the maximum possible output of a manufacturing or engineering process.
Cobble – It happens because of misroll. Misroll is a phenomenon in rolling mills in which the running material, for some reason, misses the proceeding pass and rolls down at the same place, causing the material to become waste. It causes jamming of the mill by the product while being rolled. It is also a piece of product, which for any reason has become so bent or twisted that it is to be withdrawn from the rolling operation and scrapped.
Cobble shear – It is frequently called a crop and cobble shear. It is a heavy-duty mechanical cutting machine used in hot metal rolling mills to trim the front and tail ends of a metal bar and to rapidly chop up tangled scrap during a jam.
Coble creep – It is a form of diffusion-controlled deformation where atoms move along the grain boundaries of a poly-crystalline material under a constant tensile load at high temperatures.
COBO process – It is short for cold bound process. It is a specialized, hydrothermal cold-bonding technology used to agglomerate ultra-fine iron ore or chromite fines i-nto durable pellets without traditional high-temperature firing (induration). These cold-bound pellets are subsequently utilized as a robust, pre-treated burden feedstock in a reactor or kiln for direct reduced iron (DRI) or sponge iron production.
Co-catalyst – It is a secondary substance loaded onto or mixed with a main catalyst to improve its activity, selectivity, stability, or efficiency. It is a substance which improves the photo-catalytic activity of a catalyst by lowering activation energy, facilitating charge separation, and suppressing recombination of photo-generated charge carriers, hence improving overall photo-catalytic efficiency. It can be categorized into oxidation and reduction co-catalysts, and their performance is influenced by factors such as loading quantities and microstructures.
Co-channel interference – It is an unwanted signal degradation which occurs when two or more transmitters operate on the exact same frequency channel simultaneously in overlapping or neighbouring coverage areas.
Cockcroft-Latham criterion – It is a ductile fracture model used to predict when and where a crack will initiate under plastic deformation. It assumes that ductile fracture occurs when the cumulative plastic work done by the maximum tensile principal stress reaches a critical material threshold.
Cockcroft-Latham fracture criterion = It is a ductile damage model used in metal forming to predict when a metal cracks under plastic deformation. The criterion states which fracture happens when the accumulated tensile plastic work reaches a critical material limit. It assumes that tensile stresses drive the growth and opening of internal voids, leading to a final fracture.
Cock valve – It is a type of valve which is used to control the flow and supply of fluids such as water, oil, or gas. It consists of a cylindrical chamber which contains a movable plug known as ‘cock’, which serves as an inlet and outlet for controlling fluid flow. The cock can be opened or closed to regulate the rate at which fluid passes through it. Cock valves are highly reliable and easy to install and maintain, making them ideal for many industrial applications.
Cocoa – In fretting wear, it is a powdery form of debris, normally consisting of iron oxides, which is expelled from a ferrous metal joint near the location where fretting wear is occurring.
Co-continuous composites – These are also called interpenetrating phase composites. These are materials made of two or more distinct phases where every phase is completely continuous and interconnected throughout the entire structure.
Co-continuous structure – It is also called bi-continuous structure. It is a microscopic arrangement where two or more distinct phases (such as polymer blends or material components) are each fully continuous and interpenetrating through space.
Cocoon process – It is a specialized method used to protect metal parts and equipment by using a spray gun to apply a web-like covering of plastic filaments or film-forming resin.
Co-curing – It is the act of curing a composite laminate and simultaneously bonding it to some other prepared surface, or curing together an inner and outer tube of similar or dissimilar fibre-resin combination after each has been wound or wrapped separately.
Cocurrent flow – It is a configuration in which two fluids enter a heat exchanger from the same end and flow in the same direction, resulting in a limitation where the product cannot be heated to a temperature higher than that of the heating medium’s inlet temperature.
Code-book – It is a reference document which defines and explains the structure, variables, or codes used within a dataset. It is a roadmap describing the layout, file structure, and specific variables in a data collection (like a survey).
Code-book-based precoding – It is a wireless communication technique where a transmitter maps transmission layers to multiple antenna ports using a pre-defined matrix (called a code-word) selected from a shared finite set, known as a code-book.
Code-book design – It is the systematic process of creating an optimized set of reference codes, vectors, or variables used to interpret, compress, or transmit data accurately across different domains.
Code-book size – It refers to the total number of distinct codewords or prototype vectors contained within a codebook used for quantization, compression, or visual categorization.
Code-book vector – It is a prototype or centroid vector stored inside a vector quantization code-book which represents a cluster of similar data points.
Code calibration – It is a reliability-based procedure used to determine safety factors and format design equations so that structural codes meet specific target safety levels and performance standards. The term can also refer to adjusting computer software or simulation code parameters to maximize agreement with experimental data, or programming specific configuration data into an electronic device or test strip batch.
Codec performance – It measures how well a coder-decoder (codec) balances data compression efficiency against output signal distortion or quality.
Coded image – It is raw pixel data which has been translated into a compressed, standardized digital format using mathematical algorithms.
Code division multiple access – It is a spread spectrum channel access method where multiple users share the exact same frequency band and transmit simultaneously by using unique digital code sequences.
Code division multiple access technology – It is a digital wireless communication technology which lets multiple users share the same frequency channel at the same time. Unlike older methods which split a channel by time slots (time-division multiple access) or frequency bands (frequency-division multiple access), code division multiple access technology (CDMA) gives each user a unique digital code. All users over the entire frequency spectrum at once, and the receiver uses the unique code to sort and extract the correct signal.
Code division multiplexing – It is also called code division multiple access (CDMA). It is defined as a multiplexing technology which allows multiple users to share a common frequency set by assigning unique digital codes to each user, utilizing direct sequence spread spectrum techniques.
Code domain – It refers to a multiple access technique which utilizes spreading sequences, specifically sparse sequences or non-orthogonal low cross-correlation sequences, to enable users to share the same time-frequency resource in a network. It encompasses dominant techniques such as low-density spreading CDMA (code division multiple access), low-density spreading-based orthogonal frequency-division multiplexing, and sparse code multiple access.
Code efficiency – It is a measure of how effectively a software programme executes its tasks using the minimum number of computational resources, specifically processing time and memory. Efficient code reaches the desired output using the fewest possible steps, executing faster, minimizing CPU (central processing unit) and RAM (random-access memory) overhead, and lowering overall system operating costs.
Code holes – These are defined as the information-carrying data perforations in punched paper tape used to control automated machinery, distinct from the mechanical feed or sprocket holes.
Code of conduct – It is a formal set of rules and guidelines which outlines the expected behaviours, ethical standards, and responsibilities for members of an organization, profession, or group.
Code of practice – It is a body of rules for practical guidance only and not having the force of law although failure to comply can be used in evidence in legal proceedings.
Code protection – It refers to the strategies, tools, and technical mechanisms used to secure software source code or firmware against unauthorized access, theft, reverse engineering, and tampering.
Code regulation – It is a systematically organized collection of legally binding rules and standards established by a government authority or agency to control behaviour, operations, or safety.
Code requirement – It is a mandatory rule or constraint specified in a legally binding building, engineering, or safety code which dictates how a system, product, or structure is to be designed, constructed, or operated.
Code-stream – It is a structured sequence of data or packets which represents a continuous flow of code or compressed digital media, such as an image or video.
Code transition – It is the exact point or threshold where a digital output value changes from one binary code to the next in an analog-to-digital converter (ADC).
Code vector – It is a fixed-size array or numerical sequence stored in a code-book or look-up table, used mainly in vector quantization to map and encode larger data or image vectors to their nearest representative match.
Code-word – It is a valid sequence of bits generated from a specific input sequence, which is used in error detection and correction processes during data transmission. In the context of the source, valid code-words are 7-bit sequences which can represent 4-bit input sequences without errors.
Code-word length – it is the number of symbols or bits used to represent a single codeword in a data transmission or compression code.
Code-word transmission – It is the process of sending encoded blocks of data, where extra bits are added to messages to detect and fix errors, across a communication channel.
Codimension – It is the difference between the dimension of a finite-dimensional vector space and the dimension of its subspace, mathematically expressed as dim[V] – dim[W].
Coding artifact – It is a tangible or intangible by-product produced during the software development lifecycle.
Coding delay – It is a deliberate pause or timed suspension in the execution of a programme or signal transmission.
Coding matrix – It is a structured mathematical array (such as a generator matrix) used to transform raw data into a protected, redundant format for reliable transmission or storage.
Coding scheme -it is a rule-based system which converts information, text, or binary data into a structured sequence of symbols, codes, or electrical waveforms for storage, compression, or transmission.
Coding strategy – It is a behavioural design method which lets a person to define a family of algorithms, put them into separate classes, and make their objects interchangeable at runtime.
Coding table – It is a structured reference data structure which maps short, standardized codes to their corresponding human-readable meanings or extended attributes.
Coding vector – Global coding vector (GCV) refers to a h-dimensional row vector which connects the output symbol of a network edge with the source symbols. Local coding vector (LCV) is the combination coefficients used to generate an output symbol from the linear combination of incoming symbols at an intermediate node.
Co-doped fibre – It refers to optical fibre which is doped with two types of rare-earth elements, such as erbium and ytterbium, which improves its performance by allowing the use of higher pump powers and improving optical amplification capabilities.
Co-doping – It is the intentional, simultaneous, or sequential introduction of two or more distinct dopant elements (impurities) into a host material’s crystal lattice. Unlike single doping, which adds only one type of impurity to adjust carrier concentration, co-doping creates synergetic interactions between the combined elements to fine-tune electronic, optical, or catalytic properties.
Coefficient – It is a constant numerical multiplier or ratio which measures a specific physical property, material behaviour, or system efficiency.
Coefficient matrix – It is a rectangular array which contains only the numerical coefficients of the variables from a system of linear equations.
Coefficient of compliance – It is a numerical measure of how easily a material, structure, or physiological system deforms, stretches, or yields when subjected to an external force or pressure. It is normally the inverse of stiffness or rigidity. A higher coefficient means a system or material is flexible and deforms easily, while a lower coefficient means it is stiff and resists change.
Coefficient of compressibility – It signifies decrease in void ratio per unit increase in effective stress. It is slope of void ratio against effective stress curve. It represents magnitude of volume change or settlement.
Coefficient of damping force – It is a parameter that measures how strongly a system resists motion by turning vibrational or kinetic energy into heat. It shows the link between the damping (friction) force and the speed of a moving object. The force always acts against the direction of the movement.
Coefficient of determination – It is the square of the correlation coefficient (‘r’). It indicates the degree of relationship strength by potentially explained variance between two variables.
Coefficient of draught – It is also spelled as coefficient of draft. It is a dimensionless ratio used in naval architecture and fluid dynamics to quantify the depth of a ship’s hull below the waterline relative to its total height or length, or to analyze the aerodynamic and hydrodynamic drag resistance acting on a vessel or vehicle.
Coefficient of dynamic friction – It is the coefficient of dynamic friction. It is a dimensionless number which that measures the resistance to sliding between two solid surfaces that are already moving against each other. It is the ratio of the friction force (the force pushing parallel to the surfaces to slow them down) to the normal force (the force pressing the two surfaces together).
Coefficient of elasticity – It is the reciprocal of Young’s modulus in a tension test.
Coefficient of elongation – It is a measure of how much a material stretches or expands under stress, typically expressed as a percentage of its original length. It is frequently used to characterize the ductility of a material, which is its ability to deform plastically before fracturing.
Coefficient of expansion – It is a measure of the change in length or volume of an object, specifically measured by the increase in length or volume of an object per unit length or volume.
Coefficient of friction – It is the dimensionless ratio of the friction force (F) between two bodies to the normal force (N) pressing these bodies together.
Coefficient of kinetic friction – It is the ratio of the tangential friction force to the normal load force when two bodies are in relative motion. It is typically lower than the static friction coefficient for the same material combination due to the adhesive bonds that form in static conditions.
Coefficient of linear expansion – It is the parameter indicating the length variation of a material per unit length because of a temperature change of 1K (Kelvin), typically expressed in units of 1/K.
Coefficient of performance – It is a measure of how efficiently a heating or cooling system moves heat relative to the electricity or work it consumes.
Coefficient of proportionality – It is also called the proportionality constant. It is the constant value which relates two proportional quantities.
Coefficient of thermal expansion – It is the change in unit of length (or volume) accompanying a unit change of temperature, at a specified temperature. It is also the linear or volume expansion of a given material per degree rise of temperature, expressed at an arbitrary base temperature or as a more complicated equation applicable to a wide range.
Coefficient of variation – It is also known as normalized root-mean-square deviation. It is a standardized measure of dispersion of a probability distribution or frequency distribution. It is defined as the ratio of the standard deviation (sigma)σ to the mean μ(mu) (or its absolute value, |μ||mu|), and frequently expressed as a percentage. It is widely used in analytical chemistry to express the precision and repeatability of an assay. It is also commonly used in fields such as engineering when doing quality assurance studies.
Coefficient of viscosity – It is a measure of a fluid’s internal resistance to flow. It is numerically equal to the tangential viscous force per unit area needed to maintain a unit velocity gradient between two parallel layers of a fluid.
Coefficient update – It is the iterative process of adjusting the numerical weights or parameters in an algorithm or model to minimize error and improve accuracy as new data arrives.
Coercive field – It is the intensity of an applied reverse magnetic field needed to reduce a ferro-magnetic material’s magnetization to zero after it has been magnetized to saturation. It measures a material’s resistance to being demagnetized.
Coercive force – It is the magnetizing force which is to be applied in the direction opposite to that of the previous magnetizing force in order to reduce magnetic flux density to zero, hence, a measure of the magnetic retentivity of magnetic materials.
Coercivity – It is also called coercive field (Hc). It is the externally applied magnetic field which is needed to reduce to zero the magnetic flux density of a magnetized ferro-magnetic or ferri-magnetic material.
Coexistence mechanism – It is a process or stabilizing factor which allows different species, groups, or technologies to share the same space or resources without one driving the other to extinction or total exclusion.
Coextrusion – It is the simultaneous extrusion of two or more compatible metals through a single die to form a single, integrated multi-layer product.
Coextrusion interfacial bonding – It refers to the atomic-level joining of two or more distinct metal layers forced together at high temperatures and pressures through a single die, creating a continuous metallurgical bond through interdiffusion across the contact boundary.
Coextrusion welding – It is a solid-state welding process which produces coalescence of the faying surfaces by heating and forcing base metals through an extrusion die.
Cofferdam – It is a temporary, watertight enclosure built in or around a body of water so the inside can be pumped dry for construction or repair work.
Coffin-Manson law – It is a formula which predicts how many repeated load cycles a metal can survive before breaking when it undergoes permanent, plastic deformation.
Coffin-Manson model – It is an empirical equation which relates plastic strain amplitude to the number of cycles a metal can endure before failing in low-cycle fatigue.
Coffin-Manson relation – It is a mathematical equation which predicts the low-cycle fatigue life of a metal based on plastic strain amplitude.
Coffin-Manson relationship – It is a mathematical equation which links the plastic strain amplitude of a material to its number of cycles to failure under low-cycle fatigue.
Coffin schedule – It refers to a specific sequence of steel slabs processed in a hot rolling mill, frequently shaped like a coffin because of the width changes during the rolling process. It is a key scheduling technique aimed at optimizing the rolling process by ensuring a smooth transition between slabs with varying widths and properties.
Cofiring biomass – It is the practice of partially substituting biomass for coal in coal-fired boilers to efficiently and cleanly convert biomass to electricity, resulting in reduced emissions and energy consumption. This approach has been successfully demonstrated in numerous installations worldwide and can considerably lower greenhouse gas emissions.
Cofiring test – It is an experimental evaluation of burning two different fuels simultaneously in the same combustion system, such as mixing biomass or ammonia with coal in a power plant boiler.
Co-form process – In material synthesis and template-based fabrication (such as porous carbon or nano-material production), it refers to a method where a template forms concurrently (at the same time) during the material synthesis process, rather than existing beforehand.
Co-gasification – It is the simultaneous thermo-chemical conversion of two or more different feedstocks, such as coal mixed with biomass or plastic waste, into a clean, usable gas mixture called synthesis gas (syngas).
Co-generation – It is also known as combined heat and power (CHP). It is the simultaneous production of electricity (or mechanical power) and useful thermal energy from a single fuel source.
Co-generation plant – It is also known as a combined heat and power (CHP) system. It generates both electricity and usable heat at the same time from a single fuel source.
Cogging – It is the reducing operation in working an ingot into a bloom or slab in a cogging mill or into a billet with a forging hammer or a forging press.
Cogging forge operations – It is an economical technique to convert a cast structure to a wrought structure through the use of open-die forging and furnace treatments. Traditionally, the forging elements of cogging have been carried out by using a two-die forge, but cogging can also include work done on a forge with four dies, known as a rotary forge. Cogging continues to be applicable for converting ingot structure to billet structure in a wide variety of processes, and its scope continues to increase, as is indicated by its incorporation into the recent production of powder-based billets. Two different types of cogging forge operations exist namely drawing and upsetting.
Cogging mill – It is also called a blooming mill or a slabbing mill.
Cogging process – It is an open die forging process used to convert a cast ingot into forged billet. A typical process involves hundreds of local reductions, along the length of the billet, spanning several heats. The work-piece is typically rotated between or during passes. The ingot cross section is reduced as it changes shape to a round, hexagon or octagon. This thermo-mechanical processing refines the coarse ingot grain structure to homogenized, fine grained, recrystallized billet micro-structure.
Cognition cycle -It is a recurring, closed-loop process which enables a system to sense its environment, learn from data, reason, and take automated action to optimize performance.
Cognition functions – These are the functions which are implemented through cognition elements consisting of data structures, processes, and flows, which can be modelled as topological maps over the abstract domains.
Cognition loop – It is a continuous, iterative mental or computational cycle of reasoning, action, observation, and feedback used to solve problems or adapt over time.
Cognitive approach – It is a psychological perspective which studies internal mental processes, such as memory, thinking, perception, attention, and language to explain human behaviour.
Cognitive control – It is the mental process which allows people to organize, guide, and regulate their thoughts, emotions, and actions to reach a specific goal. It is also called executive control or executive function.
Cognitive engine – It is the core component of cognitive radio which facilitates learning and decision-making for efficient spectrum sharing, enabling dynamic spectrum access and improving situational awareness and intelligence in network behaviour. It also plays a role in ensuring security and privacy across different applications.
Cognitive engineering – It is a top-down problem-driven interdisciplinary activity which focuses on human-system analysis, design, and evaluation, addressing issues such as mental modelling, human error mechanisms, and distributed decision making.
Cognitive ergonomics – It is the scientific study of how human mental processes, such as perception, memory, reasoning, and motor response, interact with tools, tasks, and environments in a system. While traditional physical ergonomics focuses on physical comfort and posture, cognitive ergonomics focuses on the brain. It ensures that products, software, and work-flows match human mental capabilities and limitations rather than working against them.
Cognitive function – It refers to the mental processes which human operators or automated systems use to acquire, process, transform, and apply information to achieve a goal.
Cognitive functioning – It is the process by which sensory input is registered, screened against prior experiences, and processed through abstraction, concept formation, reasoning, and logical analysis across the cerebral cortex, ultimately leading to an appropriate response. It encompasses different cognitive domains, including attention, memory, and processing speed, which can be influenced by factors such as age, intelligence, and emotional states.
Cognitive model – It is a psychological framework stating which people thoughts and perceptions of events, rather than the events themselves, shape their emotional, behavioural, and physiological reactions.
Cognitive modelling – It is the process of creating computer programmes, mathematical equations, or formal frameworks to simulate and explain human mental functions like perception, memory, and problem-solving. It builds a working replica or theory of how the human brain processes information and makes decisions.
Cognitive network – It is an intelligent communication system which perceives current network conditions, plans and decides actions, learns from past outcomes, and adapts autonomously to achieve end-to-end goals.
Cognitive node – It is a functional unit or device within a network or system which possesses independent processing, learning, and decision-making capabilities to perceive its environment and adapt its behaviour.
Cognitive radar – It is an intelligent radar system which senses its operating environment, learns from received signals, and dynamically adapts its parameters in real time to optimize performance.
Cognitive systems engineering – It is an inter-disciplinary design discipline which treats humans and technology as a single, unified ‘joint cognitive system’ to support and amplify human work in complex, high-risk environments.
Cognitive radio – It is an intelligent wireless communication system which senses its operational environment and automatically adjusts its transmission parameters to use the available radio frequency spectrum more efficiently. The concept builds upon software-defined radio (SDR) by adding a cognitive engine which enables the device to learn, reason, and self-adapt.
Cognitive radio network – It is a smart wireless communication system which automatically detects unused radio frequencies and adjusts its transmission settings to use the spectrum more efficiently.
Cognitive radio system – it is an intelligent wireless communication technology which senses its environment and automatically adjusts its operating parameters to use the available radio frequency spectrum efficiently. It builds upon software-defined radio by adding self-awareness and learning capabilities to find unused channels, known as ‘white spaces’, and share the spectrum without interfering with licensed main users.
Cognitive representation – It is the internal mental code, symbol, or structure which the mind uses to store, understand, and manipulate information about things that are not physically present. It serves as the brain’s internal version of external reality, allowing people to think, reason, and plan.
Cognitive robotics – It is a subfield of artificial intelligence and computer science focused on building robots with human-like intelligence, perception, and reasoning skills to act adaptively in complex, changing environments. Unlike traditional industrial robots which strictly repeat pre-programmed physical tasks, cognitive robots use advanced processing architectures, machine learning, and sensory feedback to learn from experience and make independent decisions.
Cognitive simulation – It is a computational technique where computer models are designed to mimic human thought, reasoning, and behaviour.
Cognitive skills – These are the core mental abilities and processes which the people’s brain uses to think, learn, read, remember, pay attention, and solve problems. These intellectual tools allow people to acquire, process, store, and apply information in their daily life.
Cognitive user – It typically refers to an entity, either a human interacting with a system or an intelligent agent / device in a cognitive radio network (CRN), which uses mental processing, learning, or adaptive algorithms to perceive, analyze, and make decisions.
Cognitive wireless network – It is an intelligent communication system which uses machine learning and contextual awareness to automatically adapt its operations and efficiently manage radio spectrum usage.
Coherence band-width – It is the maximum frequency range over which a wireless channel’s frequency response is considered ‘flat’, meaning all frequency components experience comparable and correlated fading and gain.
Coherence function – It is a frequency-based mathematical measure which determines the linear correlation and cause-and-effect relationship between two signals.
Coherency – It is the quality of being logical, orderly, and consistent so that all parts fit together well to form a unified whole.
Coherency strain – It is the elastic deformation which happens at the boundary between two crystals or phases when their atomic lattices do not completely match, forcing one or both lattices to stretch or compress to maintain a continuous, aligned connection.
Coherency strain energy – It is the elastic strain energy stored in a material at the bound or meeting line (interface) between two crystalline phases with different lattice dimensions (parameters) which remain joined together in a continuous, unbroken crystal lattice.
Coherency stress – It refers to the internal mechanical stresses which develop at the coherent or semi-coherent interfaces of two different crystal lattices (such as in thin films, multi-layers, or alloys) when their atomic spacings do not perfectly match.
Coherent bundle – It is an ordered assembly of optical fibres which maintains the exact same geometric arrangement and spatial orientation at both ends.
Coherent component – It is a predictable, stable, or in-phase part of a signal, wave, or system which maintains a constant or statistically steady relationship over time, unlike random or fluctuating background noise.
Coherent demodulation – It is a signal processing technique used at a receiver to recover an original message or data signal by multiplying the incoming modulated wave with a locally generated reference carrier which matches the transmitter’s carrier in both exact frequency and phase.
Coherent detection – It is an advanced signal processing technique which mixes an incoming modulated signal with a locally generated reference wave (a local oscillator) to completely extract the signal’s full amplitude, phase, frequency, and polarization information. It is normally used in modern fibre-optic communications, radar, and advanced sensing. This technique stands in contrast to standard direct detection (such as intensity modulation direct detection, or IM-DD), which only measures the presence or absence of raw optical power.
Coherent detection system – It is an advanced signal processing technique used in communication systems (mainly optical and radio frequency) that extracts the full vector profile, including amplitude, phase, frequency, and polarization, of an incoming modulated wave. Unlike traditional direct detection systems (which act like a simple on / off switch by measuring raw optical power or intensity), a coherent system introduces a reference wave at the receiver to decode multi-dimensional signals.
Coherent fibre optic bundle – It is an ordered assembly of optical fibres which maintains the exact same spatial arrangement and relative orientation at both ends, allowing for the faithful transmission of images.
Coherent heterodyne detection – It is a technique which combines a weak incoming signal with a frequency-shifted reference wave from a local oscillator on a photo-detector to measure the signal’s amplitude, phase, and frequency.
Coherent homodyne detection – It is an optical and radio-frequency measurement technique where an incoming signal is mixed with a locally generated reference beam (the local oscillator) which shares the exact same frequency and a locked phase, allowing for the precise recovery of both the amplitude and phase of the signal.
Coherent interface – It is a boundary between two crystal phases where atomic planes and lattices match continuously with a one-to-one correspondence across the boundary.
Coherent light – It is a beam of light where the electro-magnetic waves all have the same frequency and a fixed, predictable phase relationship with one another. It is maintained by precise sources, allowing for strong interference patterns.
Coherent modulation – It is a communication technique where data is encoded onto a carrier wave’s phase, frequency, or polarization relative to a fixed, synchronized reference.
Coherent-optical interference methods – These methods refer to techniques which superimpose two or more phase-correlated light waves to create stable interference patterns for high-precision measurement, imaging, or data transmission.
Coherent particle – It refers to a precipitate or phase whose crystal lattice structure matches and continues seamlessly into the surrounding matrix crystal structure.
Coherent precipitate – It is a crystalline precipitate which forms from solid solution with an orientation which maintains continuity between the crystal lattice of the precipitate and the lattice of the matrix, normally accompanied by some strain in both lattices. Since the lattices fit at the interface between precipitate and matrix, there is no discernible phase boundary.
Coherent processing interval – It is the total time span of a coherent pulse train, characterized by pulses with the same carrier frequency and known initial phase. It is necessary for organizing the transmission and reception of radar signals to ensure coherent processing of the data received.
Coherent radar – It is a radar system which preserves and compares both the amplitude and the phase history of transmitted and received radio waves.
Coherent receiver – It is an advanced signal-detection device which mixes an incoming modulated signal with a locally generated reference oscillator to recover the complete amplitude, phase, and polarization information of the wave.
Coherent rotation – It is a uniform movement where all parts of a system or magnetic moments spin together in exact coordination without changing their relative phase or alignment.
Coherent scattering – It is a type of x-ray or electron scattering in which the phase of the scattered beam has a definite (not random) relationship to the phase of the incident beam.
Coherent structure – It is an organized, stable, and recognizable pattern or arrangement within a system where all parts connect logically and work together clearly- Coherent structures refer to organized patterns within a flow that can influence its statistical characteristics, particularly in two and three dimensions, and can affect the energy cascade and spectrum in turbulent systems.
Coherent super-position – It is a quantum or wave state combining multiple states or waves with a well-defined, stable phase relationship that allows them to interfere predictably.
Coherent system of units (of measurement) – It is a system of units of measurement, in which all of the derived units are coherent.
Coherent (derived) unit (of measurement) – A derived unit of measurement which can be expressed as a product of powers of base units with the proportionality factor ‘one’. Coherency can be determined only with respect to the base units of a particular system. A unit can be coherent with respect to one system but not to another.
Cohesion – It is the state in which the particles of a single substance are held together by primary or secondary valence forces. As used in the adhesive field, the state in which the particles of the adhesive (or adherend) are held together. It also means force of attraction between the molecules (or atoms) within a single phase.
Cohesion-less soil – It is a type of soil which shows frictional-type behaviour, where the stress needed to shear the material is directly proportional to the normal stress on the plane, characterized by the angle of internal friction. This type of soil typically has higher permeability and can respond in either a drained or undrained manner during shearing events.
Cohesion strength – It is broadly defined as the maximum internal stress a material can withstand before failing because of the attractive forces holding its own molecules or atoms together. Unlike adhesion (which is the bond between different materials), cohesion is the intrinsic ‘sticking together’ force within the same material.
Cohesive crack – It is a fracture in a material where the two sides of the crack stay connected and continue to transfer pulling stress as they slowly pull apart.
Cohesive element – It is a specialized finite element used in computer simulations to model the behaviour of interfaces, joints, and adhesive layers where cracks, delamination, or separation can occur.
Cohesive energy – It is the total quantity of energy which is to be supplied to break a solid or liquid down into separate, neutral free atoms at rest at an infinite distance.
Cohesive energy density – It is the quantity of energy needed to separate all intermolecular or interatomic bonds in a unit volume of a condensed material (liquid or solid). It measures the strength of total inter-molecular forces holding a substance together in a condensed state.
Cohesive energy of a crystalline solid – It is the energy which is to be added to the crystal to separate its components into neutral, free atoms at rest, at infinite separation with the same electronic configuration.
Cohesive failure – It is the failure of an adhesive joint occurring mainly in an adhesive layer.
Cohesive force – It is the internal molecular attraction which holds identical particles, atoms, or molecules of a single material together, providing structural integrity and resistance to separation.
Cohesive interface – It is a specialized boundary layer between two materials or structures where mechanical forces, stresses, and separation are modelled using traction-separation laws rather than standard bulk material properties. It represents an interface which holds materials together (such as in composites or adhesive bonds) and helps predict how cracks initiate and spread.
Cohesive interface element – It is a specialized finite element used in engineering simulations to model the bonding, crack growth, and failure behaviour between material surfaces or layers.
Cohesive law – It is a mathematical rule which connects the stretching or pulling force at a material interface to how far apart the surfaces are pulling before they break.
Cohesive layer – It is a layer of material placed between surfaces which can pull apart, using special force rules to track how the connection stretches and breaks.
Cohesive model – It is a computational method used to simulate fracture and damage processes. It assumes that a fracture process zone exists ahead of a crack tip. Instead of dealing with infinite stress at the crack tip (a problem in older methods), it uses a relationship between traction (the pulling force per unit area) and separation (the distance the material stretches apart).
Cohesive property – It is the intrinsic molecular attraction which causes identical particles or molecules within a substance to stick together.
Cohesive set – It is a collection of elements, ideas, or components which stick together closely to form a unified, harmonious, and well-organized whole.
Cohesive soil – It is a fine-grained earth material whose particles stick tightly together because of strong inter-molecular forces and water attraction.
Cohesive strength – It is the hypothetical stress causing tensile fracture without plastic deformation. It is also the stress corresponding to the forces between atoms.
Cohesive stress – It is the internal tensile force or traction which holds the surfaces of a material together across a crack or atomic boundary.
Cohesive surface -It is an idealized boundary or interface of negligible thickness where the traction (force per unit area) relates directly to the separation distance between surfaces. It is used to model cracks, bonding, and material failure.
Cohesive traction – It is the internal stress or pulling force which develops between separating surfaces or material interfaces as they are pulled apart, typically described within a cohesive zone model.
Cohesive zone – Cohesive zone is the region lower down the blast furnace. Here, slag starts to form at around 1,100 deg C. Initially it is relatively viscous, and surrounds the iron oxide particles, preventing further reduction. As the temperature increases to level of around 1,400 deg C to 1,450 deg C, it melts and reduction continues. This region is critical in terms of burden permeability.
Cohesive damage zone – It refers to a localized region which develops near the tip of a crack in quasi-brittle materials, where inelastic material response is concentrated, and is characterized by the relationship between tractions and displacement jumps at the crack interfaces.
Cohesive zone length – It is the distance from the physical crack tip to the point ahead of it where the maximum cohesive traction (stress) is attained in a cohesive zone model.
Cohesive zone method – It is a numerical analysis technique used in fracture mechanics to simulate crack initiation and propagation by modeling material separation along a virtual process zone ahead of a crack tip.
Cohesive zone model – The damage ‘D’ in cohesive model is described as proportional of the effective to the maximum separation by complete material failure. It bis the description of cleavage failure by means of a cohesive zone model. The dissipated energy of the cohesive elements serves as a failure criterion.
Coil – It consists of insulated wire which is wound onto a spool through which electric current is passed to create a magnetic field, It is an assembly consisting of one or more magnet wire windings. It is also the form in which rolled metal sheet, strip or wire rod is produced. Coil, in an electric circuit, has one or more turns, normally roughly circular or cylindrical, of current-carrying wire designed to produce a magnetic field or to provide electrical resistance or inductance. In the latter case, a coil is also called a choke coil.
Coil area – It refers to the cross-sectional area of a single turn or loop in an electro-magnetic coil, or the total surface face area in heat-transfer applications.
Coil box – Coil box on a hot strip mill is a coiling device which is located after the roughing stand and just prior to the finishing stands. Its purpose is to collect the strip in coil form and temporarily store it. Then it uncoils the strip for further rolling. Its main function is to maintain the temperature of the steel strip from head to tail ends and improve productivity.
Coil breaks – These are creases or ridges in sheet or strip which appear as parallel lines across the direction of rolling and which normally extend the full width of the sheet or strip.
Coil condition – It refers to the physical and operational state of the heating or cooling coils in an HVAC (heating, ventilation, and air conditioning) system which regulate air temperature and humidity.
Coil conveyor – It is a massive, heavy-duty mechanical transport system designed to transfer enormous, hot-rolled or cold-rolled metal coils (steel, aluminum, or copper) between processing lines, cooling areas, and storage bays. In machine tool engineering, a coil conveyor (interchangeably called a shaftless screw or spiral chip conveyor) is a bulk-handling mechanism consisting of a coreless, rotating steel spiral or square-profile coil enclosed inside a trough.
Coil, copper – A copper coil is defined as a type of coil made from copper material, which can be designed in different geometries such as flat, helical, or with different cross-sections, and can be classified based on its number of turns and specific applications.
Coil curvature – It is the longitudinal bow in an unwound coil in the same direction as curvature of the wound coil. It is also known as coil set.
Coil, diameter – It is the outside diameter of an individual coil winding. This measurement is used as the size of the visual referenced circle drawn around each coil on the field heatmap. For a single-coil disc or loop, it is the entire accessory’s coil diameter. For a multi-coil mat, it is the diameter of each individual coil, much smaller than the mat’s overall width or height. When coil diameter is not specified, the heatmap estimates it from the distance between detected coils. It is also the overall width or span of an individual loop or winding in a helical spring or coil.
Coiled product processing – It refers to the sequential manufacturing steps that transform heavy rolls of sheet metal (coils) into flat, precisely sized blanks or smaller strips for manufacturing. The main steps are flattening, leveling, slitting, and shearing.
Coiled products – These refer to continuous lengths of manufactured materials, such as metal sheets, strips, and tubing, wound into cylindrical rolls, or conductive wires wound into helical shapes to manage electrical and magnetic energy.
Coiled sheet – It is normally known as a metal coil. It is a continuous, flat-rolled metal strip or sheet which has been wound into a cylindrical roll. It is the sheet in coils with slit edges.
Coiled tubing – It refers to a continuous length of flexible metal or composite tubing with no joints, supplied spooled on a large reel, and is used in different applications in the petroleum industry, including drilling, cementing, and wellbore cleanout. It allows for efficient chemical delivery and intervention in downhole operations.
Coiled wire – It is a length of conductive metal wire or cable which has been wound into a continuous spiral, helix, or loop pattern.
Coiled wire insert – It is a precision-formed, spring-like metal coil, which is screwed into a pre-tapped hole to create durable internal threads for a bolt or screw.
Coil element – It is a length of conductive wire, normally made of metal alloys like nichrome or copper, wound into a spiral or helix shape to either generate heat through electrical resistance or create a magnetic field.
Coiler – It is sometimes called recoiler. It is an auxiliary equipment in the hot strip mill and cold rolling mill used for coiling hot-rolled or cold-rolled steel strip into a roll shape. It is arranged behind the last finishing stand on the hot strip mill (hot strip mill), cold rolling mill.
Coil fabrication – It is the process of manufacturing, shaping, and assembling raw metal or wire into a spiral or helical configuration (a coil) for industrial, electrical, or thermal applications.
Coil forming – It consists of progressively bending or winding the sheet, strip, or wire products into cylindrical rolls or coils which are finished products. Coil forming is also the process of shaping insulated conductive wire into structured, precise multi-layered loops (coils) to fit into the slots of electromagnets, transformers, stators, or electric motor rotors. This process transforms ‘random-wound’ or loose wire into rigid, insulated geometric shapes, known as form coils.
Coil forming roll – It is a specialized, precisely machined wheel or die used in a continuous roll-forming machine to incrementally bend and shape flat metal strips, fed from a metal coil, into a specific 3D cross-sectional profile.
Coiling – It is the final manufacturing process where long, continuous strips, sheets, or wire rods of metal are wound into tight, cylindrical rolls or coils.
Coiling arm – It is a mechanical component used to wind materials, such as wire, cables, sheet metal, or springs, into tight, uniform coils or spools.
Coiling machines – Coiling machines are used to wound long rolled products into coils. Making coils of the rolled products facilitates handling and improves the yield.
Coiling of spring wire – it can be done either by cold winding or hot winding. In case of cold winding the steel wire (normally up to 18 millimeters diameter) is coiled at room temperature using one of two basic techniques. One consists of winding the wire around a shaft called an arbour or mandrel. In the second technique, the wire can be coiled without a mandrel. This is normally done with a CNC (computer numerical control) machine. In case of hot winding, thicker wire or round bar can be coiled into springs by heating the steel to make it flexible. Standard industrial coiling machines can handle steel bar up to 75 millimeters in diameter, and custom springs have reportedly been made from bars as much as 150 millimeters thick. The steel is coiled around a mandrel while red hot.
Coiling station – It is the specific section, module, or stand-alone assembly within a production line where a continuous, elongated material is wound and organized into a compact, secure coil. It acts as the main mechanical interface which transforms loose, continuous output, such as steel strips, wire, electrical cables, or plastic tubing, into neatly packed, transportable bundles.
Coiling temperature – It is the exact temperature at which a hot-rolled metal strip or wire is wound into a roll (coil) after finishing the rolling process.
Coil opener – It is an industrial machine used to safely unbind, release, and feed the initial leading end (head end) of a heavy rolled metal coil into a processing or leveling line.
Coil orientation – It refers to the physical alignment and spatial positioning of a coiled component (such as an electrical inductor, electro-magnetic winding, mechanical spring, or raw metal roll) relative to its surrounding system, reference axes, or magnetic / fluid fields. In electronics and electromagnetics, coil orientation defines how a winding’s axis aligns with magnetic fields. It dictates the behaviour of motors, transformers, and wireless charging systems. In mechanical design, coil orientation refers to the direction of the wind (helix direction) of a compression, extension, or torsion spring. In industrial manufacturing and logistics, coil orientation defines how giant master rolls of sheet steel, aluminum, or paper are positioned for transport and processing. This orientation can be eye-to-the-sky (vertical axis) or eye-to-the-side (horizontal axis). In thermal and fluids engineering such as heat exchangers and HVAC (heating, ventilation, and air conditioning) equipment, fluid coil orientation refers to the physical position of the tubes (horizontal or vertical) through which refrigerant or water flows.
Coil orientation, clockwise coil – It means that with the coil core vertical (eye to the sky) and viewed from above, a trace of the metal edge from the inside diameter to the outside diameter involves clockwise movement.
Coil orientation, counter-clockwise (anti-clockwise) coil – It means that with the coil core vertical (eye to the sky) and viewed from above, a trace of the metal edge from the inside diameter to the outside diameter involves counter-clockwise (anti-clockwise) movement.
Coil processing – It is the manufacturing method which unwinds, flattens, shapes, and cuts heavy metal coils into usable sheets, rods / wires or smaller strips.
Coil reforming chamber – For ensuring the optimum coil package, the coil is to be formed in an orderly manner and also completely formed inside the upper portion of the coil reforming chamber. The ordering of the rings coming off the exit section is achieved with a ring distributor, which is a proven design of rotating blade within the upper portion of the chamber which directs how the rings fall onto the forming coil. The reform ring distributor collects rings high in the reforming chamber using a rotating blade for optimal placement. This system shortens the coil package, easing shipping, and storage space concerns, which in turn reduces costs. Improved collection also results in better-shaped coils for fewer tangles and snags at pay-off.
Coil set – It is the longitudinal bow in an unwound coil in the same direction as curvature of the wound coil. It is also known as coil curvature.
Coil set differential – It is the difference in coil set from edge to edge of a coiled sheet sample. It is measured with the sample on a flat table, concave side up, and is the difference in elevation of the comers on one end.
Coil set, reversed – It is the longitudinal bow in an unwound coil in the direction opposite the curvature of the wound coil.
Coil size – It refers to the specific physical dimensions, such as width, thickness, inner / outer diameter, and weight, which define a wound or cylindrical material or electrical component.
Coil spring – It is also known as helical spring. It is made by winding a wire around a cylinder or a cone. In case wire is wound on a cone then the spring is called a conical spring. Coil springs are usually of two types. The first type consists of a compression spring which is designed to become shorter when loaded. Their turns (loops) are not touching in the unloaded position, and they need no attachment points. A volute spring is also a compression spring in the form of a cone, designed so that under compression the coils are not forced against each other, thus permitting longer travel. The second type consists of tension or extension springs which are designed to become longer under load. Their turns (loops) are normally touching in the unloaded position, and they have a hook, eye or some other means of attachment at each end.
Coil transition – It refers to a thermodynamic and conformational change where a macro-molecule transitions between a disordered, fluctuating ‘random coil’ state and a highly ordered or structurally distinct conformation.
Coil voltage – It is the specific quantity of electrical input needed to energize the electro-magnetic coil inside a device like a relay or contactor, creating a magnetic field which moves mechanical contacts to switch a circuit.
Coil winding – In electrical engineering, coil winding is the manufacture of electro-magnetic coils. Coils are used as components of circuits, and to provide the magnetic field of motors, transformers, and generators, and in the manufacture of loudspeakers and microphones.
Coil width – It is the flat, transverse measurement of a rolled strip of material (such as steel, aluminum, or copper) from one edge to the opposite edge before it is unrolled or formed.
Coin – It is a flat, standardized piece of metal, normally a disc, stamped with an official authority’s insignia, serving as a certified medium of exchange and legal tender.
Coinability – It is the suitability of a metal or alloy to take a sharp, clear, and struck impression between dies in a coining press during cold-forming operations.
Coinage alloys – These are specific mixtures of metals (alloys) engineered for minting circulating currency. These alloys are designed to balance cost-effectiveness, high wear resistance, corrosion resistance, and anti-counterfeiting properties while remaining malleable enough to accept a stamped design. Historically, coinage alloys have relied on precious metals, but modern metallurgy focuses on durable base metals and clad (layered) compositions.
Coinage metals – These are the group of three metallic elements, copper (Cu), silver (Ag), and gold (Au), which form Group 11 of the periodic table and have historically been used to mint coins. These specific elements have earned their collective name since their physical beauty, chemical stability, scarcity, and durability made them the universal choice for currency.
Coincidence circuit – It is an electronic device with multiple inputs and a single output that activates only when it receives input signals simultaneously or within a very short, specified time window.
Coincidence effects – These refer to the phenomenon where two or more gamma-rays emitted simultaneously during the decay of the same nucleus are recorded as a single pulse within the resolution time of the detecting system, which can lead to inaccuracies in measuring full-energy peak efficiency.
Coincidence gate – It is an electronic device with two or more inputs and a single output which activates only when it receives input signals simultaneously within a specified time window.
Coincident mate – It is a standard computer-aided design (CAD) assembly constraint which forces two separate geometric entities, such as faces, planes, edges, or points, to share the exact same location in space.
Coincident site lattice – It is a three-dimensional super-lattice formed when a specific fraction of lattice points coincides when two misoriented crystal lattices interpenetrate.
Coincident site lattice (CSL) boundary – it is a geometric reference model describing a special type of grain boundary where a specific fraction of atoms from two adjoining, misoriented crystal lattices overlap.
Coining – Coining is the process of applying compressive stress on surface of the raw material in order to impart special shapes on to the surface from the embossing punch, e.g., coins, and medallions. It is a closed-die squeezing operation, normally performed cold, in which, all the surfaces of the work are confined or restrained, resulting in a well-defined imprint of the die upon the work. It is also a restriking operation used to sharpen or change an existing radius or profile. It also means the final pressing of a sintered powder metallurgy compact to get a definite surface configuration.
Coining dies – These are the dies in which the coining or sizing operation is performed.
Coining tolerances – These refer to the exceptionally tight dimensional limits and high-precision accuracy achieved by applying intense compressive force to plastically deform a metal part inside closed die.
Coin silver – It is an alloy containing 90 % silver, with copper being the normal alloying element.
Coin straightening – It is a combination coining and straightening operation performed in special cavity dies designed to impart a specific amount of working in specified areas of a forging to relieve the stresses developed during heat treatment.
Coin test – it is a test using a coin to tap a laminate in different spots, listening for a change in sound, which would indicate the presence of a defect. It is a surprisingly accurate test in the hands of experienced personnel.
Co-ions – These are ions in a solution which have the same electrical charge (positive or negative) as the fixed, immobile charges inside an ion exchanger or on a charged surface.
Coke – It is a hard porous carbon material produced in the process of the ‘destructive distillation’ of various blends of bituminous coal, petroleum, or coal tar pitch which drives off most of the volatile matter. It has a multiple role. It is a reducing agent, source of reducing carbon mono-oxide gas, a source of heat, a filter of dust and soot, and a carburizer of hot metal, besides supporting the burden and providing gas permeability. It has several uses.
Coke ash – Coke ash is the mineral matter present in the coke. Metallurgical coke typically contains around 8 % to 12 % of mineral phases. The proportion of individual minerals present in coke can vary from coke to coke depending on the mineralogy of the original coals as well as the process conditions employed for carbonization.
Coke bed – It is the first layer of coke placed in the cupola. Also, it is the coke used as the foundation in constructing a large mould in a flask or pit.
Coke, beehive – Beehive coke is a hard, grey, porous carbon fuel made by baking coal in a dome-shaped brick kiln called a beehive oven with limited air. This old industrial process burns off unwanted impurities to create strong fuel used in metal smelting.
Coke breeze – It is the fines (-10 millimeters) from coke screenings. It is use in sintering of ores, in blacking mixes after grinding, and is also briquetted for cupola use.
Coke by-products – These are the secondary gases, liquids, and chemical substances recovered when coal is heated in the absence of air to make metallurgical coke. Instead of escaping as waste during high-temperature carbonization, these volatile vapours are captured and processed into industrial fuels and raw chemical materials.
Coke, by-product – By-product coke is a hard, porous carbon material made by heating coal in a closed oven without air, where the volatile gases released during the process are collected and saved to make useful chemicals and clean fuel, rather than being wasted.
Coke carbon – It is the nearly pure carbon produced from the calcination of petroleum coke, which serves as a critical raw material for manufacturing carbon anodes used in aluminum smelting.
Coke drum – It is a large vertical pressure vessel used in oil refineries to convert heavy oil residues into lighter, valuable products and solid petroleum coke.
Coke dry quenching – It is an energy saving process used during the production of coke in the coke oven battery. A coke dry quenching plant is also called coke dry cooling plant (CDCP). In the dry quenching process, the red-hot coke is cooled by mixed gas (mainly consisting of nitrogen) circulating in an enclosed system, thereby preventing the release of airborne coke dust. The thermal energy of the red-hot coke, which is lost in the conventional wet quenching, is collected and reused as steam.
Coke dry quenching bucket cars – These are designed for receipt of coke having the temperature of 1,000 deg C to 1,050 deg C from the chamber of coke oven battery in its coke bucket and transports the bucket with coke by means of electric loco to the coke dry cooling plant for lifting and discharging of coke into quenching chambers of coke dry cooling plant. The bucket is designed to have a maximum of durability.
Coke furnace – It is a type of pot or crucible furnace which uses coke as the fuel.
Coke guide and transfer car – Coke guide and transfer car is designed for servicing the coke side of the coke oven battery. The main operations to be fulfilled by the coke guide car are (i) extraction and installation of door, (ii) approach-withdrawal of coke guide cage to oven, (iii) directing coke descent in coke transfer car, (iv) cleaning of doors and frames, (v) collecting of dust-gas mixture, and (vi) removal of coke spillage.
Coke manufacture – It is the industrial process of heating specific grades of bituminous coal to high temperatures (typically 900 deg C to 1,400 deg C) in an enclosed oven without oxygen or air, a process known as pyrolysis or destructive distillation.
Coke micro-texture – The micro-texture of coke is the organization of the material at the intermediate scale from the nano-metric to the micro-metric scale. Micro-texture is the result of the mutual orientation in space of poly-aromatic ‘basic structural units’ (BSU) with size about 1 nano-metrer formed by poly-aromatic layers (4 to 10 rings) stacked by 2 or 3. Coke is composed of differently sized ‘molecular orientation domain’ (MOD) as coals are generally chemically heterogeneous. Coke micro-texture can be characterized by the distribution of molecular orientation domain sizes varying from 5 nano-meters to a few micro-meters.
Coke, non-recovery oven – It is coke made in non-recovery oven. It is a hard, high-purity carbon fuel made by baking coal at very high heat without air. Unlike standard ovens, it burns the gases made during baking inside the unit to create heat instead of saving those gases to make chemical by-products.
Coke, nut – Nut coke is fraction of the coke in the size range of +10 millimeters to -30 millimeters. It is charged with the ore burden in the blast furnace.
Coke oven batteries – Coke oven batteries consist of a number of coke ovens which can vary from 20 to 100 in each battery.
Coke oven emissions – These emissions come from large ovens that are used to heat coal to produce coke, which is used to manufacture iron and steel. The emissions are complex mixtures of dust, vapours, and gases that typically include carcinogens such as cadmium and arsenic. Coke oven emission means the benzene-soluble fraction of total particulate matter present during the carbonization of coal.
Coke oven gas – It is a by-product gas produced during the production of metallurgical coke in a by-product coke oven battery, where metallurgical coal is carbonized by heating it in absence of air. It is a colourless gas with an odour characteristics of hydrogen sulphide and hydrocarbons. Its major constituents are hydrogen, methane, and carbon mono-oxide. It has a calorific value ranging between 17 mega-joules to 19 mega-joules per normal cubic meter. It has a theoretical flame temperature of 1982 deg C. It has a rate of flame propagation which allows its actual flame temperature to be close to its theoretical flame temperature.
Coke oven machines – These machines are an integral part of any coke oven battery. These machines charge the ovens with the coal feedstock, push the coke from the ovens after coking, and feed it to the coke quenching process. The different types of coke oven machines are (i) coal charging car, (ii) coke pusher machine for the top charged ovens, (iii) coal stamping cum coke pusher machine for stamped charge ovens, (iv) coke guide and transfer car, (v) coke quenching car or coke bucket car with electric locomotive, and (vi) door service car.
Coke ovens – Coke ovens are the chambers made of refractories to convert coal into coke by carbonizing coal in absence of air and there by distilling the volatile matter out of coal.
Coke, petroleum – Petroleum coke, also called pet-coke, is a solid, carbon-rich by-product created during the thermal cracking of heavy residual oils in refinery coker units. Engineering applications divide it into fuel-grade or calcined anode-grade carbon utilized in aluminum and steel production.
Coke porosity – It is the fraction of void space (pores and fissures) in a metallurgical coke volume, normally expressed as a percentage. It is calculated using the formula ‘(P = (Do -Da)/ Do x 100, comparing the true density ‘Do’ of the solid carbon matrix to the apparent bulk density ‘Da’. Coke porosity is the fraction of void space (pores and fissures) inside a lump of coke compared to its total volume, typically ranging from 30 % to 50 %. This internal cellular network directly controls how well the coke burns, absorbs gases, and supports the burden in a furnace.
Coke pusher machine – The coke pusher machine travels along the length of the battery and carries out various functions such as (i) remove and replace coke oven doors, (ii) push out hot coke from the oven, (iii) open and close leveller bar doors, (iv) level the coal charge in the oven, (v) clean doors, frame and flash plates, (vi) degraphitize the oven ceiling, and (vii) remove the coke spillage. The pusher machine is located at the coke oven battery side and is normally designed for the single spot operation. The drives of machine can be hydraulic or electro-mechanical. Operator’s cabin, and the hydraulic and electronic equipment cabins are normally equipped with air-conditioners. The main functional units of the coke pusher machine are (i) travelling mechanism, (ii) pushing mechanism, (iii) door latch unscrewing mechanism, (iv) door snatching mechanism, (v) door turning mechanism, (vi) travelling mechanism for door extractor installation, (vii) door cleaning mechanism, (viii) door frame and flash plate cleaning mechanism, (ix) levelling mechanism, (x) leveller bar door opening mechanism, (xi) coal charge spillage collecting system, (xii) coke spillages collecting device with quenching system, (xiii) degraphitizing mechanism.
Coke quenching car – In case of wet quenching, two different types of wet quenching cars are used. These two types are one which is used for conventional top spray quenching and the second which is used for coke stabilizing quenching. These cars are of robust design or can be self-propelled or locomotive driven. The conventional quenching car is a fixed sloped bottom car with a pneumatically or hydraulically operated discharge gate. The flap opening mechanism is self-locking, so that no uncontrolled opening of the gates can occur. The coke stabilizing quenching car has a fixed sloped bottom and is fitted with all facilities for coke box flooding and quick water drainage. The coke box is closed by two gates. The inner gate holds the coke inside the box, but lets the water drain. The outer gate holds the water inside the box.
Coke rate – Coke rate is the parameter for the consumption of blast furnace coke. It is measured in kilograms of blast furnace coke consumed per ton of hot metal produced.
Coke reactivity – Coke reactivity is one of the most important factors which control the bed permeability in the blast furnace. The lower the coke reactivity the higher is the permeability of the burden in the BF. The coke reactivity is influenced by its three major properties of coke namely (i) micro-texture which determine the number of active sites, (ii) micro-structure which controls diffusion and chemical rates, and (iii) constituent minerals which can have a catalytic effect.
Coke reactivity Index – It is a standard measurement which defines the percentage of weight loss a metallurgical coke sample undergoes when exposed to carbon di-oxide (CO2) at high temperatures (typically 950 deg C). Coke reactivity Index (CRI) measures how easily metallurgical coke gasifies through the endothermic Boudouard reaction [C + CO2 = 2CO (reversible reaction)] inside a blast furnace: ‘CRI (%) = [(M1-M2)/ M1] x 100, where M1 is the weight of the dry coke sample before the CO2 reaction., and M2 is the weight of the coke sample after reaction with CO2.
Coke strength after reaction – It is an engineering metric which measures the mechanical strength and structural integrity of metallurgical coke after it reacts with carbon di-oxide (CO2) at high temperatures. Developed by Nippon Steel Corporation in the 1970s, it simulates the harsh thermal and chemical environment inside a blast furnace. The standard testing procedure evaluates coke hot strength in two sequential stages (governed by International Organization for Standardization standard ISO 18894.
Coke wet quenching process – In the coke wet quenching process the red-hot coke which is pushed from the coke oven is cooled by spraying water on the hot coke. The water used for cooling is vapourized and released into the atmosphere. An issue with this conventional system is the energy loss when the thermal energy of the red-hot coke is converted into the steam which is vapourized and released unused. Another drawback is that the coke wet quenching process also produces airborne coke dust, and hence, this process is associated with high carbon di-oxide emissions and thermal energy loss.
Coking coal – It is a type of bituminous coal. The term ‘coking coal’ is used to designate certain types of bituminous coals which, when heated at high temperatures (over 1,000 deg C) in the absence of air (carbonization), soften, liquefy, and then re-solidify into a hard but porous mass known as coke. Coking coal is also referred as ‘metallurgical (met) coal’. The mean maximum reflectance (MMR) values for the coking coals in case of low volatile coals are normally in the range of 1.42 % to 1.75 %, in case of medium volatile coals normally in the range of 1.05 % to 1.4 %, and in case of high volatile coals normally in the range of 0.7 % to 1.02 %.
Coking drum – It is a large vertical pressure vessel used in oil refineries to convert heavy residual oil into lighter hydro-carbons and solid petroleum coke through thermal cracking.
Coking pressure – Coking pressure is a phenomenon which results from the pressure of the gases within the plastic layers and it is transmitted to the walls of the ovens through the coke and semi-coke already formed. Coking pressure has become important because of the use of the double-heated wall, vertical, slot-type coke ovens. In the round beehive ovens as well in the heat recovery coke ovens, which are also being used for coke production, the coal can freely expand upwards and thus the swelling of the charge is accommodated by this free expansion. On the other hand, in the slot-type coke ovens, the expansion of the coal horizontally to the heated wall is restricted. There are several cases of premature failure of oven walls during the coal carbonization process.
Colburn factor – It is a dimensionless number used to express and evaluate the performance of convective heat or mass transfer at a fluid boundary layer. It is heavily utilized to predict and optimize the efficiency of fluid transport systems, most notably in the design of compact heat exchangers.
Cold ablation – It is a material removal process which occurs independently of thermal cycles, mainly through the breaking of chemical bonds by high-energy photons or through multiphoton absorption in ultrashort laser pulses. This mechanism leads to ionization and plasma expansion, resulting in minimal heat conduction and a clean surface finish.
Cold and hot water rinsing – These are sequential cleaning steps used to remove chemical residues, active plating solutions, and surface contaminants from metal parts between processing baths.
Cold blast pig iron – It is crude, high-carbon iron (3.5 % carbon to 4.5 % carbon) produced in a blast furnace where the combustion air blown into the hearth is at ambient or near-ambient temperature (not pre-heated). This lower-temperature blast yields slower, highly controlled smelting which historically produced iron with unique strength and low impurity profiles compared to hot-blast methods.
Cold blast valve – Cold blast valve is intended for the complete separation of the blast furnace stove from the cold blast main. It is installed on the horizontal cold blast main near the stove. These valves are normally not lined since the temperature of the cold blast is normally in the range of 150 deg C to 250 deg C, which is the temperature resulting from the heat of compression at the blower.
Cold bond briquetting – It is an important process which is used to recycle and utilize the plant waste by-products of fine particle size. The briquetting process converts the fine particles into cold bonded briquettes. In this process, different waste by-products are agglomerated using very small quantity of the binder. The briquetting process avoids heating up, softening, and melting the fine particles, which saves a lot of fossil energy and decreases the environmental pollution.
Cold bonding – It is a process used to join two materials or parts together without using heat or thermal energy. Unlike traditional hot-work methods like welding or brazing which melt materials to fuse them, cold bonding relies on high-strength chemical adhesives, epoxies, or physical pressure to establish a permanent bond at room temperature.
Cold box – It is normally an insulated container designed to keep items cool or cold during transport or short-term storage. In an air separation plant, a cold box is a large, insulated vessel which houses equipment operating at cryogenic temperatures. It is a critical component for maintaining the low temperatures needed to liquefy air and separate its components like oxygen and nitrogen.
Cold box process – It is a rapid core-making process which does not need application of heat to cure the cores. Hardening of the cores is accomplished by chemical reaction rather than by conventional baking. A phenolic resin is added to the sand used to make the core. This resin reacts chemically when exposed to an accelerator, typically an active organic gas, and hardens very quickly, forming an organic bond in the core sand. This reaction occurs at room temperature and does not require special core-boxes or equipment. Additionally, since the bond is organic, the sand collapses readily during shakeout and can be recovered easily from the casting. This process utilizes a two-part binder system, typically consisting of phenolic urethane (a resin) and a catalyst (such as an amine gas). The sand mixture is blown into the core box, and the catalyst is introduced to the resin-coated sand, leading to rapid curing and hardening of the core.
Cold briquetted iron – It is direct reduced iron which has been briquetted when it is cooed after its discharge from the furnace.
Cold cathode – It is an electrode which emits electrons without needing external heating. This directly contrasts with ‘hot cathodes, which rely on a heated filament to boil off electrons through thermionic emission. Instead of heat, a cold cathode triggers electron emission through alternative mechanisms, very frequently by applying a high-voltage gradient (field emission) or through ion bombardment (secondary emission) where gas ions strike the surface to knock electrons free.
Cold chain – It is a temperature-controlled supply chain which maintains perishable or sensitive products within a specific, safe temperature range from production through storage, transport, and final delivery.
Cold chamber – It refers to a component of a specific type of die casting machine where molten metal is transferred into an unheated injection cylinder. In HVAC (heating, ventilation, and air conditioning), a cold chamber is an insulated structure or enclosure served by a refrigerating system designed to maintain a controlled, low-temperature environment.
Cold chamber die casting – It is a manufacturing process where molten metal is ladled from an external furnace into an unheated injection chamber (shot sleeve) before a plunger forces it into a mould under high pressure.
Cold chamber machine – It is a die casting machine with an injection system which is charged with liquid metal from a separate furnace.
Cold chamber, club sandwich, two-faced, three-pieced die – It is a die-casting die in which two different pieces are cast in two widely separated cavities.
Cold coined forging – It is a forging which has been restruck cold in order to hold closer face distance tolerances, sharpen corners or outlines, reduce section thickness, flatten some particular surface, or, in the non-heat-treatable alloys, increase hardness.
Cold compacting – This is the standard compaction method under which the metal powder mix is compacted without sintering to a green body at room temperature.
Cold compressive strength – It is the maximum load (applied under specified conditions at room temperature) divided by the area over which the load is applied, that a refractory withstands before failure occurs.
Cold crack – It is a crack which develops after solidification is complete.
Cold cracking – It consists of forming cracks in cold or nearly cold cast metal because of the excessive internal stress caused by contraction. It is frequently brought about when the mould is too hard or the casting is of unsuitable design. In welding, it is a type of weld cracking which normally occurs below 205 deg C. Cracking can occur during or after cooling to room temperature, sometimes with a considerable time delay. Three factors combine to produce cold cracks namely stress (for example, from thermal expansion and contraction), hydrogen (from hydrogen-containing welding consumables), and a susceptible microstructure (plate martensite is most susceptible to cracking, ferritic and bainitic structures are least susceptible).
Cold crucible induction melting – It is an advanced industrial melting technique which uses electro-magnetic induction to heat and melt conductive materials inside a water-cooled, segmented metal container without causing chemical contamination.
Cold crucible melting – It is a method of evaluating steel cleanliness. In it, the inclusions are first concentrated at the surface of the melted sample as in the electron beam (EB) melting. After cooling, the sample surface is then dissolved, and the inclusions are filtered out of the solute. This method improves on slime extraction.
Cold crushing strength – It is a measure of the mechanical strength of the refractory brick. In furnaces, cold crushing strength is of importance, because of bricks with high crushing strength is more resistant to impact from rods or during removal of slag than a brick with a low cold crushing strength. It is a useful indicator to the adequacy of firing and abrasion resistance in consonance with other properties such as bulk density – and porosity.
Cold die pressing – It is a manufacturing process which uses mechanical or hydraulic force to shape or compact raw materials (such as metal or ceramic powders, or solid metal blanks) inside a rigid mould or die at room temperature.
Cold die quenching – It is a quenching which utilizes cold, flat, or shaped dies to extract heat from a part. Cold die quenching is slow, expensive, and is limited to smaller parts with large surface areas.
Cold direct reduced iron – It is the direct reduced iron which is discharged from the furnace in cold condition (temperature around 50 deg C).
Cold drawing – It is a metalworking process which pulls a metal stock through a die at room temperature to reduce its cross-sectional area, lengthen it, and improve its shape and surface finish.
Cold drawn pipe – It is a high-precision metal tube processed at room temperature by pulling a hot-rolled base tube through a shaping die. It is tubing drawn cold through steel or carbide die to elongate and improve its dimensional accuracy.
Cold environment – It is a region on earth where average temperatures stay at or below 0 deg C for long periods or most of the year.
Cold etching – It is the etching to reveal micro-structure which is conducted at room temperature and below.
Cold expansion – It is a mechanical surface treatment and manufacturing process used to strengthen metal components by forcing an oversized tool through a pre-drilled hole. This action permanently deforms the material surrounding the hole, creating a protective barrier of compression which considerably improves the fatigue life of structures.
Cold extrusion – Cold extrusion of metals involves forcing the material through a die at room temperature for creating a continuous product of consistent cross-section. Cold extrusion is so called since the billet / slug or preform enters the extrusion die at room temperature. During the process, however, the deforming material undergoes deformation heating (conversion of deformation work to heat) to several hundred degrees. Typically, a punch is used to apply pressure to the billet enclosed, partially or completely, in a stationary die. Cold extrusion is a forging operation which has the typical advantages of material savings, work-hardening (strengthening), and grain flow or directional strengthening. Cold extrusion involves backward (indirect), forward (direct), or combined backward and forward (indirect-direct) displacement of metal by plastic flow under steady, though not uniform, pressure.
Cold filter plugging point – It is the lowest temperature at which a specific volume of diesel or distillate fuel can still pass through a standardized filtration device within a set time limit when cooled under controlled conditions. It serves as an important indicator of a fuel’s low-temperature operability, estimating the threshold where wax crystals are going to accumulate enough to clog fuel filters and cause engine performance issues or starting failures.
Cold finger – It is a liquid-nitrogen-cooled cold trap used to reduce contamination levels in vacuum chambers.
Cold-finished bars – These are metal bars (such as carbon or alloy steel) which undergo secondary processing at room temperature to improve their surface finish, dimensional accuracy, and mechanical strength.
Cold flow – It is the distortion which takes place in materials under continuous load at temperatures within the working range of the material without a phase or chemical change.
Cold flow improver – It is a chemical additive mixed into diesel, biodiesel, or heating oil to prevent the fuel from thickening, waxing, or gelling in cold weather.
Cold flow property – It describes how well a fluid or material maintains its ability to flow or resist permanent deformation at low temperatures. It measures how well diesel, biodiesel, jet fuel, or engine oil flows in cold weather. Low temperatures cause wax crystals to form or the fluid to thicken, which can clog filters and starve engines.
Cold fluid – It is a liquid or gas with a lower temperature and higher density than a surrounding or interacting warmer fluid, or a designated coolant used to absorb and transfer heat away from a system.
Cold forging – It is a metal shaping process where a metal work-piece is compressed at or near room temperature to achieve its desired shape. This process results in increased hardness and strength through work-hardening, unlike hot forging which involves heating the metal.
Cold formability – It is the ability of a metal to undergo permanent, plastic deformation at or near room temperature, below its recrystallization temperature, without cracking, fracturing, or failing.
Cold-formed copper welding tip – It is a contact tip or electrode made of copper, or a copper alloy like chromium-zirconium copper, shaped at room temperature through mechanical pressure rather than high heat.
Cold-formed steel – It is steel shaped at or near room temperature through mechanical working processes like rolling, bending, or pressing.
Cold forming – It is a metal working process in which metal is shaped below its recrystallization temperature, normally at the ambient temperature. Cold forming techniques are normally classified into four major groups namely squeezing, bending, drawing, and shearing. They normally have the advantage of being simpler to carry out than hot working techniques.
Cold-form tapping – It is a manufacturing process which creates internal screw threads by displacing and pressing metal rather than cutting it away.
Cold front – It is leading edge of an advancing mass of cold, dense air which displaces and pushes underneath a mass of warmer, lighter air. Since cold air is denser than warm air, it acts like a wedge, forcing the warm air rapidly upward into the atmosphere. On weather maps, a cold front is represented by a solid blue line with triangles pointing in the direction which the front is moving.
Cold fusion – It is a highly speculative theoretical process in which two like-charged atomic nuclei overcome the Coulomb barrier at normal temperatures and pressures.
Cold fusion phenomenon – It is very frequently referred to as low-energy nuclear reactions (LENR). It is a hypothesized type of nuclear reaction which occurs at or near room temperature. It involves forcing isotopes of hydrogen (such as deuterium) to fuse into heavier elements like helium inside solid materials (like palladium or nickel), releasing vast quantities of clean energy and excess heat without needing the extreme millions-of-degrees temperatures found in conventional thermonuclear reactors.
Cold galvanizing – It is the process used to touch up and / or repair hot dipped galvanized surfaces and providing barrier protection as well as some cathodic protection.
Cold gas efficiency – It is the ratio of the chemical energy contained in the produced syngas (or product gas) to the chemical energy input from the solid or liquid feedstock (such as coal or biomass). It measures how effectively a gasifier converts solid fuel energy into gas fuel energy at standard ambient temperature (excluding the sensible heat of the hot gas).
Cold heading – It consists of working metal at room temperature such that the cross-sectional area of a portion or all of the stock is increased.
Cold-heading lubricants – These are specialized oils or coatings used to reduce friction and wear between metal parts and dies during room-temperature shaping. These are high-performance fluids designed to handle extreme pressure and heavy mechanical loads when shaping metal wire into fasteners like screws and bolts.
Cold-heading lubrication – It is the application of specialized oils or coatings to metal wire and forming dies to reduce friction, prevent galling, and extend tool life during room-temperature metal deformation.
Cold-heading machine – It is a specialized mechanical press which shapes metal wire or rod into fasteners and precision components at room temperature using high-pressure dies and punches.
Cold heading quality steels – These are quality of steels used for making of fasteners by cold heading process. The steel is to be very clean and without any internal or external defects.
Cold-heading wire rods – These are specialized, high-purity metal wire rods designed to undergo extreme plastic deformation at room temperature without cracking.
Cold high-pressure separator – It is a specialized industrial pressure vessel used in petro-chemical refinery hydro-processing units (such as hydro-treating and hydro-cracking) to separate hydrogen-rich recycle gases from hydrocarbon liquids and water. Unlike hot separators which handle initial high-temperature reactor effluents, the cold high-pressure separator (CHPS) operates at or near ambient temperatures while maintaining a high operating pressure (typically ranging between 1.75 mega-pascals to 30 mega-pascals).
Cold injection moulding – It normally refers to a cold runner injection moulding system, where the channels (runners) which deliver molten material to the mould cavity are unheated and cool down alongside the final part.
Cold inspection – It is a visual (normally final) inspection of forgings for visible imperfections, dimensions, weight, and surface condition at room temperature. The term can also be used to describe certain nondestructive tests such as magnetic-particle, dye-penetrant, and sonic inspection.
Cold isostatic pressing – It is a forming technique in which high fluid pressure is applied to a powder (metal or ceramic) part at ambient temperature. Water or oil is used as the pressure medium.
Cold junction – It is the reference temperature point in a thermocouple circuit where the dissimilar metal wires connect to a measurement instrument.
Cold junction compensation – It is a technique used in thermocouple measurements to adjust for the ambient temperature at the connection point, ensuring accurate indication of the true temperature by offsetting the instrument zero.
Cold lap – It consists of wrinkled markings on the surface of an ingot or casting from incipient freezing of the surface and too low a casting temperature. It is also a flaw which results when a work-piece fails to fill the die cavity during the first forging. A seam is formed as subsequent dies force metal over this gap to leave a seam on the work-piece surface.
Cold leg break – It refers to a rupture in the cold leg of a reactor system, which leads to a higher initial flow rate and results in an earlier failure of the reactor vessel’s lower head compared to a break in the hot leg. This scenario is considered more dangerous because of the accelerated accident progression and increased hydrogen generation, contributing to core heat up and degradation.
Cold metal transfer – It is a modified gas metal arc welding process which uses high-speed digital control and mechanical wire retraction to achieve extremely low thermal input and nearly spatter-free material deposition.
Cold mill – It is an industrial machine set-up which reduces metal strip or sheet thickness and improves surface finish by passing the material through rollers at room temperature, below the metal’s recrystallization point.
Cold moulding – It is a process for making moulded items using resins which cure or polymerize chemically at room temperature rather than needing external heat.
Cold oil quenching – It is a heat-treatment process where heated metal is rapidly submerged into an oil bath kept at lower, room-like or moderately controlled temperatures to harden the material while preventing cracks or warping.
Cold plastic deformation – It is also known as cold working or strain hardening. It is the permanent shaping of a metal or material at a temperature below its recrystallization point, normally at room temperature, by applying mechanical force.
Cold pressing – It consists of forming a powder metallurgy compact at a temperature low enough to avoid sintering, normally room temperature.
Cold radial forging – It is a manufacturing process where multiple high-speed hammers compress a metal work-piece from radial directions at room temperature to reduce its cross-sectional area or form internal and external profiles.
Cold recycled material emulsion – It is frequently referred to as cold recycled mixture with emulsion. It is a sustainable material used mainly in road construction and pavement rehabilitation. It is defined as a pavement mix produced at ambient temperature by combining reclaimed asphalt pavement (RAP) with an asphalt / bitumen emulsion, water, and optional active fillers (like cement or lime) without the application of heat. since Cold recycled material emulsion (CRME) reuses 100 % of old, milled road surface materials, it is highly valued as an energy-saving, low-carbon alternative to traditional hot mix asphalt (HMA).
Cold reduction – It means reducing the thickness of the pickled hot-rolled strip / sheet to make the steel thinner, smoother, and stronger by applying pressure, rather than heat. It is done by rolling of pickled hot-rolled coils in cold rolling mill.
Cold reheat – It is the steam which exhausts from a high-pressure (HP) turbine and travels back to a boiler to be reheated before driving an intermediate- or low-pressure turbine. It is steam which has done partial work in the high-pressure turbine, dropping in temperature and pressure, and is routed through cold reheat piping toward the boiler’s reheater section.
Cold reservoir – It is an idealized thermal body which operates at a relatively low, constant temperature and absorbs heat from a system without changing its own temperature. Since it is conceptually modelled as having an infinitely large heat capacity, it can absorb large quantities of waste heat without warming up.
Cold resistance – Normally, conveyor belts are resistant to up to -30 deg C. Lower temperatures can be achieved with special compounds. Constant movement of the belt is needed for cold resistance.
Cold-rolled sheets – It is a metal mill product produced from a hot-rolled pickled coil which has been given substantial cold reduction at room temperature. The resulting product normally needs further processing to make it suitable for the majority of the common applications. The normal end product is characterized by improved surface, higher uniformity in thickness, and improved mechanical properties compared with hot rolled sheet.
Cold rolled steels – These are sheet steels which have been pickled and run through a cold rolling mill. A cold rolled strip has a final product width of around 300 mm, while sheet can be more than 2000 mm wide. Cold-rolled sheet is considerably thinner and stronger than hot-rolled sheet.
Cold-rolled steel sheet stampings – These are precision-formed metal components manufactured by pressing flat cold-rolled steel sheets through custom tool and die sets at room temperature.
Cold-rolled steel stampings – These are precision-formed components manufactured by shaping cold-rolled sheet metal using mechanical or hydraulic presses and specialized dies at room temperature.
Cold rolled strip – Cold rolled strip is the flat product which, immediately after the final rolling pass is wound into a coil. Cold rolled strip as rolled has slightly convex edges, but it can also be with sheared edges or slit from wider strip.
Cold roll forming – It is a metal-working process where a strip of metal is gradually shaped into a specific profile by passing it through a series of rotating rolls. This process occurs at temperatures below the metal’s recrystallization point, meaning the metal is not heated before forming.
Cold rolling – It is a metal-working process which passes metal stock through rollers at or near room temperature, specifically below its recrystallization temperature, to reduce thickness, increase strength, and create a smooth surface finish.
Cold rolling mill – It is a rolling mill for cold rolling of sheet or strip. It is an industrial facility used to reduce the thickness of metal strip or sheet by passing it through heavy rollers at or near room temperature, well below its recrystallization point.
Cold rolling textures – These refer to the preferred, aligned orientations of microscopic crystal grains which develop inside a metal when it is compressed and stretched through rollers at room temperature.
Cold runner injection moulding system – It is a feed network of unheated channels inside a mould which directs molten plastic from the machine nozzle into the mould cavities, where the plastic in the channels solidifies during each cycle and is ejected alongside the finished part.
Cold runner system – It consists of channels inside an unheated mould which carry melted plastic from the machine nozzle into the mould cavity.
Coldry process – It is a process which changes the naturally porous form of low rank coals to produce a dry and dense pellets by a process which is called as ‘brown coal densification’(BCD). The Coldry process combines two unique aspects namely (i) brown coal densification, and (ii) waste heat utilization. The drying process is based on the release of moisture in the coal, by initiating an exothermic reaction, because of the abrasion of the carbon particles together. The result is a concentrated product in the form of densified pellets which are durable, easy to store and transport, and which have similar energy value normally associated with several of the black coals, whilst significantly reducing carbon di-oxide emissions compared to its original brown coal form. The process consists of six steps namely (i) screening and feed control, (ii) attritioning and extruding, (iii) conditioning, (iv) pack bed drying, (v) water recovery, (vi) production of Coldry pellets. The process stimulates a natural chemical reaction within the coal. This reaction polymerizes active sites in the coal compounds and expels chemically bound water. The polymerization of the active sites collapses the coal pore structure and expels the physically trapped water. The ejected water migrates to the surface of the coal pellets. The surface water is evaporated by the utilization of waste heat.
Coldry technology – It consists of expelling of water from a wide range of low rank coals (lignite coals and sub-bituminous coals) containing up to 70 % moisture into high calorific value (CV) black coal equivalent (BCE) pellets with a moisture content of around 10 %. It changes the naturally porous form of low rank coals to produce a dry and dense pellets by a process which is called as ‘brown coal densification’(BCD). The process combines two unique aspects namely (i) brown coal densification, and (ii) waste heat utilization. The process stimulates a natural chemical reaction within the coal. This reaction polymerizes active sites in the coal compounds and expels chemically bound water. The polymerization of the active sites collapses the coal pore structure and expels the physically trapped water. The ejected water migrates to the surface of the coal pellets. The surface water is evaporated by the utilization of waste heat from an adjacent power plant.
Cold sawing – It is a mechanical cutting process which uses a toothed circular blade rotating at low speeds to shear metal while transferring nearly all cutting heat into the expelled chips, keeping both the blade and the work-piece cool.
Cold set – It is the hardening or setting of a refractory mortar which takes place at room temperature. Bonding mortars containing agents which give them higher strength after drying than is obtained with a clay or other refractory base alone are said to be air-setting or cold-setting.
Cold-setting adhesive – It is a synthetic resin adhesive capable of hardening at normal room temperature in the presence of a hardener.
Cold-setting binders – These are chemical resins mixed with sand which harden at room temperature without needing external heat. These binders lock sand grains together to form strong moulds and cores for metal casting.
Cold-setting process – It refers to any material curing, hardening, or permanent-deformation operation performed at ambient room temperature without external thermal input or baking. It mainly defines ambient chemical curing or room-temperature mechanical pre-stressing. In foundry practice, it consists of any of several systems for bonding mould or core aggregates by means of organic binders, relying on the use of catalysts rather than heat for polymerization (setting).
Cold shearing – It is a mechanical cutting process used to slice or crop metal bars, sheets, or rolled profiles at ambient room temperature without melting or forming chips.
Cold shears – These shears are for cutting of cooling bed lengths into saleable lengths. They are installed downstream of the cooling bed exit roller table after the straightener. Cold shears can also be flying shears.
Cold short – It refers to a metal, especially steel or iron, which is brittle and prone to cracking or fracturing under mechanical stress at ordinary or low room temperatures.
Cold shortness – It is brittleness which exists in some metals at temperatures below the recrystallization temperature.
Cold-shortness threshold – It is the specific environmental temperature or chemical composition limit at which a material shifts from a ductile state to a highly brittle state, causing a drastic loss in impact strength.
Cold shot – It is a portion of the surface of an ingot or casting showing premature solidification. It is caused by splashing of molten metal onto a cold mould wall during pouring. It is also small globule of metal embedded in, but not entirely fused with, the casting.
Cold shut – It is a linear discontinuity which appears on the surface of cast metal as a result of two streams of liquid meeting and failing to merge prior to solidification. It is also a lap on the surface of a forging or billet which has been closed without fusion during deformation. It is freezing of the top surface of an ingot before the mould is full. It is a forging defect developed by metal flowing into a section from two directions, resulting in a discontinuity at the junction.
Cold shut void – It happens when gas or air becomes trapped right at the non-fused interface, or when the localized premature freezing blocks the flow of subsequent liquid metal.
Cold sintering – It is a method for densifying ceramic materials at temperatures less than 400 deg C.
Cold sintering process – It is a low-temperature manufacturing technique which uses a transient liquid phase and external pressure to densify powder materials into a solid mass. Unlike traditional sintering, which needs extreme heat approaching 70 % to 80 % of a material’s melting point (frequently over 1,000 deg C), cold sintering typically operates at temperatures of 25 deg C to 300 deg C and intermediate pressures of 30 megapascals to 500 megapascals.
Cold slip casting – It is a room-temperature ceramic manufacturing process where a liquid slurry of fine powder and water is poured into a porous mold to form a solid or hollow shape.
Cold soldered joint – It is a joint with incomplete coalescence caused by insufficient application of heat to the base metal during soldering.
Cold spraying – It is a solid-state coating and additive manufacturing process where solid powder particles are accelerated to supersonic velocities and deposited onto a substrate without melting. Unlike traditional thermal spray techniques which rely on high temperatures to melt materials, cold spraying relies mainly on kinetic energy.
Cold spray process – It is a solid-state deposition and coating technique where tiny solid powder particles are accelerated to supersonic velocities (300 metres per second to 1,500 metres per second) using a compressed gas jet and bonded through high kinetic impact rather than melting.
Cold spray technology – It is a solid-state material deposition process where fine powder particles (typically metal or alloys) are accelerated to supersonic speeds (300 metres per second to 1,500 metres per second) using a heated, high-pressure gas passing through a specialized convergence-divergence (de Laval) nozzle. Unlike traditional thermal spray methods or welding, cold spray operates at temperatures considerably below the melting point of the coating material.
Cold stamping – It is a manufacturing process which shapes sheet metal or applies metallic foil at room temperature without using external heat. It uses a mechanical or hydraulic press and a custom mould (die) to cut, bend, deep-draw, or deform sheet metal at ambient temperature. In packaging, cold stamping is an inline printing technique used to transfer metallic foil onto packaging.
Cold-stream process – In powder metallurgy, it is a method of producing cleavage fractures in hard particles through particle impingements in a high-velocity cold gas stream. It is also referred to as impact crushing.
Cold thermal energy storage – It is a technology which chills and stores a medium, such as water, ice, or phase-change materials, during off-peak hours (like at night) and discharges that stored cooling capacity later during peak-demand hours to lower electricity costs and reduce grid strain.
Cold trap – It is a laboratory or industrial device designed to condense and capture vapours (except for permanent gases like nitrogen and oxygen) by chilling them into a liquid or solid state. It is typically installed in a vacuum circuit between the vacuum chamber and the vacuum pump.
Cold treatment – Cold treatment of steel consists of exposing the ferrous material to sub-zero (- 85 deg C) temperatures to either impart or improve specific conditions or properties of the material. Increased strength, greater dimensional or microstructural stability, improved wear resistance, and relief of residual stress are among the benefits of the cold treatment of steel. Normally, 1 hour of cold treatment for every 25 mm of cross section is adequate to achieve the desired results. When the treatment involves the transformation of retained austenite, it is normally followed by tempering.
Cold trimming – It is the removal of flash or excess metal from a forging at room temperature in a trimming press. It is the process of removing excess metal, known as flash, from a forged component using a trimming press while the metal is at room temperature.
Cold upset forging – It is a manufacturing process which compresses a metal work-piece along its axis at room temperature to increase its cross-sectional area and form a wider head or thickened section.
Cold upsetting – It is a metal-forming process performed at room temperature where an axial compressive force is applied to a wire or rod blank, compressing its height and forcing the metal to flow radially outward to form a larger cross-section.
Cold utility – It is an external cooling medium or heat sink used to absorb and remove excess heat from process streams which cannot be cooled further by internal heat recovery. It is important for bringing chemical processes to their precise target temperatures and managing exothermic reactions safely.
Cold water injection – It is the process of pumping water at a lower temperature into a hot subsurface environment, such as a geothermal reservoir or oil formation, to cool the surrounding rock, induce thermal contraction, and create or expand fractures which improve fluid flow and permeability.
Cold water rinsing – It is an ambient-temperature water immersion or spray process used to remove residual chemical solutions, acids, or loose contaminants from a metal surface between processing stages.
Cold welding – It is a solid-state welding process in which pressure is used at room temperature to produce coalescence of metals with substantial deformation at the weld.
Cold work – It is the shaping of metal below its recrystallization temperature, nmormlly at room temperature. It changes the metal shape using force. This process makes the metal stronger and harder, gives it a smooth surface, and creates tight size accuracy. It is permanent strain in a metal accompanied by strain hardening.
Cold-worked alloy – It is a metal mixture which has undergone plastic deformation (shaping or bending) at or near room temperature, well below its recrystallization temperature. The cold working process changes the internal crystal structure of the alloy by multiplying dislocations and elongating grains, which prevents easy atomic movement.
Cold-worked structure – It is a micro-structure resulting from plastic deformation of a metal or alloy below its recrystallization temperature.
Cold work hardening – It is also known as strain hardening. It is the process where a metal becomes harder and stronger when it is permanently bent, rolled, or hammered at room temperature.
Cold working – It is deforming metal plastically under conditions of temperature and strain rate which induce strain hardening. Normally, but not necessarily, it is conducted at room temperature. Cold working induces stresses which can be released during the galvanizing process.
Cold-working capacity – It is the maximum quantity of plastic deformation a metal can undergo below its recrystallization temperature, normally at room temperature, before it loses ductility and cracks or fractures. It measures a material’s formability and capacity for strain hardening (work hardening) without failing.
Cold working temperature – It is the temperature at which a plastic deformation process is carried out. This temperature is below the metal’s recrystallization temperature, typically at or near room temperature (ambient temperature). Unlike popular assumption, ‘cold’ does not mean freezing or a specific low absolute value. It is strictly relative to the specific melting point and recrystallization threshold of the metal being shaped. For example, a refractory metal with a very high recrystallization temperature can undergo ‘cold working’ at a high temperature, which is considered hot for another metal, as long as it remains below that specific alloy’s recrystallization point.
Cold work radial forging – It is frequently referred to as cold swaging. It is a high-precision, incremental metal forming process where multiple opposing dies or hammers simultaneously apply rapid, compressive radial forces around the circumference of a work-piece at temperatures below its recrystallization point (normally room temperature). This process reduces the cross-sectional area and increases the length of bars, tubes, or shafts, allowing for the creation of precise internal or external geometries without heating the material.
Cold work tool steels – These tool steels have high strength, hardenability, impact toughness, and wear resistance. These steels can be oil hardening type, air hardening medium alloy type, or high carbon high chromium type. These steels are used in those working conditions where operating temperatures are typically less than 200 deg C. These tool steels are used on larger parts or those parts which need minimal distortion during hardening. The use of oil quenching and air hardening helps reduce distortion as opposed to higher stress caused by quicker water quenching. More alloying elements are used in these steels, as compared to water-hardening grades. The alloys in these steels increase the steel’s hardenability, and hence need a less severe quenching process. These steels are also less likely to crack. Typical applications include cold working operations such as stamping dies, draw dies, burnishing tools, coining tools, and shear blades.
Colebrook equation – It is an implicit empirical formula used in fluid mechanics to calculate the Darcy-Weisbach friction factor for turbulent flow in pipes. It is a mathematical relationship which connects the friction factor to the Reynolds number and the relative roughness of channel walls, needing iterative numerical methods for solving due to its implicit nature.
Colebrook-White equation – It is an empirical mathematical relationship used in fluid mechanics to calculate the Darcy-Weisbach friction factor for turbulent fluid flow through a pipe. It bridges the gap between smooth pipe flow and fully rough pipe flow by combining experimental data and boundary layer theory. Basically, the equation serves as the mathematical foundation for the turbulent region of the widely used Moody-diagram.
Cole-Cole equation – It is an empirical relaxation model used to describe frequency-dependent dielectric, conductive, and resistive properties in materials like polymers and soils.
Cole-Cole plot – It is a graphical representation which plots the imaginary component of a complex electrical property (like permittivity or impedance) against its real component across a range of frequencies.
Collaboration – It is a process through which parties who see different aspects of a problem can explore constructively their differences and search for (and implement) solutions which go beyond their own limited vision of what is possible. Collaboration is a mechanism for leveraging resources, dealing with scarcities, eliminating duplication; capitalizing on individual strengths, building internal capacities, and increasing participation and ownership strengthened by the potential for synergy and higher impact.
Collaborative control – It is a systems engineering and automation framework where a group of multiple agents (humans, robots, vehicles, or software models) work together as peers to achieve a common goal by sharing information, decision-making, and responsibilities. Unlike traditional centralized control (where one master system dictates everything) or decentralized control (where agents act completely independently), collaborative control relies on bi-directional communication, shared situational awareness, and joint execution.
Collaborative work – It is a purposeful, joint practice where two or more individuals or organizations combine their knowledge, skills, and resources to achieve a common goal or produce a shared outcome. Rather than working in isolation, participants operate with ongoing interdependence, meaning each person’s choices directly affect and are affected by the rest of the team. True collaborative work flattens traditional hierarchies, puts contributors on an equal footing, and prioritizes co-creation and collective accountability over individual results.
Collapse – It is the out-of-round condition of coil frequently because of the inappropriate tension during rewinding operations.
Collapse analysis – It is an advanced computational simulation used to determine the ultimate load capacity of a structure and evaluate its structural integrity up to the point of complete or partial failure. Unlike standard elastic analysis, which only predicts how a structure behaves under normal operational loads, collapse analysis simulates what happens when materials yield, buckle, fracture, and completely give way under extreme or abnormal stresses.
Collapse design – It refers to an engineering methodology where a system or structure is deliberately analyzed and engineered to withstand ultimate, catastrophic failure conditions rather than just normal, everyday operational loads.
Collapse mechanism – It is defined as the specific arrangement of plastic hinges (and potentially real hinges) which at transforms a stable, load-bearing structure into an unstable kinematic mechanism capable of moving or deforming indefinitely without any additional load. When a structure reaches this state, it has exhausted its ultimate load capacity, and any further increase in force results in structural failure or collapse.
Collapse potential – It is a soil mechanics index which measures the percentage of volume or height reduction a metastable, unsaturated soil undergoes when it gets wet. It is the relative magnitude of soil collapse at a given vertical stress level when the soil is flooded or saturated with water.
Collapse pressure – It is the maximum external differential pressure which a hollow tubular component (such as a pipe, casing string, production tubing, or vessel) can withstand before it catastrophically deforms inward or crushes because of the buckling under compressive hoop stress. It represents the exact threshold where the external forces acting on the outside perimeter of the tube sufficiently exceed the internal pressure, causing a total or partial loss of structural integrity.
Collapsible conveyor – It is a flexible and expandable conveyor system, demanding regular checks to ensure the proper functioning of extension and retraction mechanisms.
Collapsible core – It is a specialized injection mould component used to form complex internal features, such as threads or undercuts, in plastic parts. It consists of segments which retract inward after cooling, allowing the part to eject smoothly without needing an internal unscrewing mechanism.
Collapsible soil – It is a type of unsaturated, low-density soil which undergoes a sudden and substantial reduction in volume (settlement) when it becomes wet or is heavily loaded, even without any increase in pressure. Also known as metastable soil, it typically possesses high dry strength and stiffness, but it rapidly loses its structural integrity and collapses upon moisture infiltration.
Collapsible sprue – It is a sprue pattern of flexible material, or of spring-tube design, used in squeeze-molding of plated patterns, and incorporating a pouring cup.
Collapsible tube – It is a cylindrical, hollow container made of soft metal or plastic with a nozzle and cap on one end, designed to flatten or collapse as people squeeze out its contents.
Collapsibility – It is the quality, capacity, or property of an object, system, or structure being able to fold, cave in, or shrink into a smaller, more compact form. It is also the tendency of a sand mixture to break down under the pressures and temperatures developed during casting.
Collar – It is a short fire-clay section of a horizontal retort which is placed between the main silica portion and the mouth piece.
Collar bearing – It is also known as a thrust bearing. It is a type of bearing used to resist axial loads, or forces acting along the axis of a rotating shaft. These bearings use one or more collars on the shaft to bear the axial pressure.
Collars – These are ring-shaped metal devices which clamp around a shaft. The purpose of the collar is normally to hold motor components, gear assemblies, sprockets, bearings, and other parts in place and sometimes facilitate their proper movement.
Collateral information – It refers to secondary, supporting, or auxiliary data—such as design files, schematics, material test reports, and specifications, which accompany a main system or project.
Collection – It is a data structure which groups multiple individual items or elements into a single operational unit to store, retrieve, and manipulate them efficiently. Common examples of collections include lists, arrays, sets, and maps used in software programming.
Collective effective dose – It is the quantity obtained by multiplying the average effective dose by the number of people exposed to a given source of ionizing radiation. Its unit is man-sievert.
Collective pitch control – It is a traditional method of pitch control in wind turbines where the same control action is applied collectively to all blades, utilizing a PID (proportional, integral and derivative) control law which relies on rotor speed variation as the error signal for closed-loop control. This method aims to regulate power production and reduce mechanical loads on the turbine.
Collector – It is a device, component, or system designed to gather, absorb, or direct energy, fluids, electrical currents, or materials. It is also a device used for removing gas borne solids from flue gas.
Collector adsorption – It is the process by which flotation collectors adhere to mineral surfaces, needing specific conditions such as the immobilization of collector species and the development of hydrophobic characteristics to achieve effective separation in mineral processing.
Collector aperture – It is the projected area or opening of a solar thermal or photo-voltaic collector which intercepts and admits incoming solar radiation. It acts as the main surface through which sunlight enters the collector system before reaching the absorber.
Collector array – It is a configuration of multiple collector modules, typically used in large-scale systems, designed to improve efficiency and reduce installation costs by minimizing the number of hydraulic connections and mounting supports.
Collector-base junction – It is the p-n junction formed between the collector and the base regions of a bipolar junction transistor (BJT). It functions as one of the two main internal interfaces in a transistor (the other being the emitter-base junction) and is important for controlling the output current of the device.
Collector distance – It is the physical span between the tip of the spinneret (nozzle) and the grounded collection plate. It is an important operating parameter which directly determines the quality, uniformity, and thickness of the resulting fibres. It heavily impacts several physical dynamics. In solar thermal energy and commercial photovoltaic installations, collector distance is defined as the minimum geometric spacing required between rows of solar collectors to avoid inter-row shading. This distance is calculated to optimize land or roof space while ensuring that one row does not cast a shadow over the row behind it. The optimum distance is mathematically calculated using a few distinct parameters.
Collector efficiency – It is the ratio of useful heat energy captured by the collector to the total solar radiation incident upon its surface area over the same time period. Basically, it measures how effectively a solar thermal panel converts sunlight into usable thermal energy.
Collector efficiency factor – It is a dimensionless thermal performance parameter used in solar thermal engineering. It is the ratio of the actual useful heat collection rate to the heat collection rate which would occur if the entire absorber plate has been at the local fluid temperature. Basically, it measures the effectiveness of heat transfer from the solar absorber plate to the working fluid. For standard flat-plate solar collectors, its value typically ranges from 0.8 to 0.95.
Collector electrode – It is a conductive element designed to capture, attract, or receive electrical charges, ions, or chemical products generated elsewhere in a system. It is a conductive component in an electronic, vacuum, or electrochemical device designed to capture or receive charged particles (such as electrons or ions) or to collect electric current from an active material.
Collector-emitter voltage – It refers to the potential difference (voltage) between the collector and emitter terminals of a bipolar junction transistor (BJT). It measures the electric potential of the collector relative to the emitter and is a main metric for determining the transistor’s current operating region (such as cut-off, active, or saturation).
Collector inlet temperature – It is the temperature of the fluid entering a collector, which can influence the efficiency of energy collection, as indicated by the relationship between the collector inlet temperature and the useful energy collected.
Collector junction – It is the p-n junction formed between the central base region and the outer collector region of a bipolar junction transistor (BJT). It serves as the main exit gateway for electrical charge carriers in a transistor.
Collector loop – It is a closed plumbing system used in solar thermal energy plants and water heaters to absorb solar radiation and transfer it as thermal energy. It is the main circuit which connects the solar collector array directly to a heat storage tank or an intermediate heat exchanger.
Collector performance – It refers to how effectively a solar thermal collector converts incoming solar radiation into usable thermal energy. The main measure of performance is defined as the ratio of useful heat energy gained by the working fluid (such as water or air) to the total solar radiation incident on the collector’s surface over a given time period.
Collector plate – It is a dark-coloured, heat-absorbing metal sheet inside a flat-plate solar collector which absorbs sunlight and converts it into heat. It is also the positively charged metal electrode that receives (collects) the electrons emitted from a light-sensitive target plate.
Collector resistance – It is the external load resistor connected to the collector terminal of a bipolar junction transistor (BJT) in a circuit, or the intrinsic parasitic resistance within the physical collector region of the semiconductor device. It is also the internal collector resistance, which is the inherent, physical resistance encountered by electrical current as it flows through the collector region of a transistor.
Collector side – It refers to the portion of a circuit or device which connects to the collector terminal of a bipolar junction transistor (BJT). In solar energy systems, the collector side refers to the piping, valves, and loop configurations which directly manage the fluid flowing through solar collector modules.
Collector storage wall – It is a passive solar heating system made of a heavy, dark-painted wall facing the sun with an outer glass cover.
Collector system – It means a system of pipes, in one part or multipart, which collects and systemizes the discharged polluted industrial waters. It also means the electrical transmission infrastructure, including conductors, towers, sub-stations, switch-gear and other components necessary to deliver power from any commercial facility generating electricity from wind or solar up to, but not including, electric sub-stations or similar facilities necessary to interconnect to existing or future transmission lines which serve load or export energy.
Collector voltage – It refers to the electric potential or voltage at the collector terminal of a bipolar junction transistor (BJT). In practical electronics and circuit analysis, it is rarely looked at as an isolated absolute value; instead, it is defined and measured in three distinct ways depending on the reference point in the circuit:
Collet – It is a split sleeve used to hold work or tools during machining or grinding.
Colligative properties – These are the properties of a solvent which change in proportion to the number of solute particles dissolved in it, and are independent of the solute’s chemical structure. These properties include vapour pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure. These are the properties of plastics based on the number of molecules present. Most important are certain solution properties extensively used in molecular weight characterization.
Collimate – It is to make parallel to a certain line or direction.
Collimated – It means rendered parallel.
Collimated roving – It is the roving which has been made using a special process (normally parallel wound), so that the strands are more parallel than in standard roving.
Collimation – It is the operation of controlling a beam of radiation so that its rays are as nearly parallel as possible.
Collimator – It is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spatial cross section of the beam to become smaller (beam limiting device).
Collinear cracks – These refer to multiple distinct cracks which form close to one another and grow along the same straight line or shared plane. When materials are subjected to stress, these cracks can propagate ‘head-to-tail’ along their common axis.
Collision – It is a brief event where two or more bodies exert strong forces on each other, resulting in an exchange of momentum and energy.
Collisional process – It is a fundamental interaction between two or more physical bodies, such as atoms, molecules, electrons, ions, or macroscopic objects, which come close enough to exert a mutual influence and exchange momentum, energy, or charge.
Collision avoidance – It refers to the use of technology, sensors, and algorithms to monitor an environment and take action to prevent or mitigate impacts between objects. It is the use of sensors, technology, or maneuvering rules to detect hazards and prevent moving objects or vehicles from crashing into other objects, people, or vehicles.
Collision cascade – It is a series of rapid, sequential atomic collisions in a solid or liquid material, triggered by the impact of a high-energy particle like an ion, neutron, or atom. When this energetic particle strikes a target atom, it permanently knocks it out of its regular position in the crystal lattice. That displaced atom then goes on to strike neighbouring atoms, creating a branching chain reaction of atomic displacements. The process continues until the kinetic energy of the moving atoms drops below the material’s displacement threshold energy, meaning they no longer have enough power to dislodge any more atoms.
Collision case – It is a defined scenario or event where two or more bodies exert large forces on each other over a very short time, resulting in an exchange of momentum and energy. In structural, mechanical, and safety engineering, a ‘collision case’ or ‘collision scenario’ is used as a design or testing baseline (such as a worst-case impact analysis) to evaluate how structures like vehicles, ships, or infrastructure absorb energy and resist damage.
Collision cross-section – It is defined as the effective area representing the probability of a collision occurring between two or more particles, which varies based on the interaction strength and the characteristics of the particles involved.
Collision detection – It is the process of using algorithms to detect when objects come into contact or penetrate each other. It is important for providing realistic force feedback and improving the overall realism of simulations. Collision detection involves determining the objects involved, the area and depth of contact, and the angle of penetration. Different algorithms and data structures are used to perform these computations quickly and accurately.
Collision dynamics – It refers to the interactions between particles in a fluid system, where particles undergo alternating streaming and collision steps, leading to momentum-conserving stochastic processes which build up fluid correlations within defined collision environments.
Collision efficiency – It is the cross-sectional area of undisturbed fluid containing particles which ultimately impinges on a given solid surface, divided by the projected area of the solid surface.
Collision exists – It refers to a situation in which the compass bearing of an approaching vessel does not appreciably change, indicating a potential risk of collision. Additionally, there can be a risk even when the bearing does change, particularly when near large vessels or at close range.
Collision frequency – It is the total number of collisions which occur between particles per unit time in a given volume. It is a core concept in the kinetic theory of gases, chemical engineering, and materials processing used to predict reaction rates, diffusion, and transport properties.
Collision impact – It is a sudden, high-magnitude force delivered over a very short duration when two or more bodies collide, resulting in a rapid transfer of kinetic energy and momentum.
Collision operator – It is a mathematical operator which describes the interactions between particles in a system, specifically relating to changes in particle distribution because of the collisions, frequently represented in the context of a Maxwellian distribution. It is characterized by bilinear expressions and shows properties such as symmetry and non-positivity in a Hilbert space of functions.
Collision point – It is the specific spatial location and geometric coordinate where the trajectories, surfaces, or boundary points of two or more moving or stationary bodies intersect and interact.
Collision resistance – It is a property of a hash function which makes it nearly impossible to find two different inputs that produce the same output.
Collodion replica – In metallography, it is a replica of a surface cast in nitro-cellulose.
Colloid – It a heterogeneous mixture where microscopic insoluble particles (ranging from 1 nano-meter to 1 micro-meter in size) are suspended evenly inside a continuous medium of a solid, liquid, or gas without settling under gravity. It is also a finely divided organic substance which tends to inhibit the formation of dense scale and results in the deposition of sludge, or causes it to remain in suspension, so that it can be blown from the boiler.
Colloidal – It is a state of suspension in a liquid medium in which extremely small particles are suspended and dispersed but not dissolved.
Colloidal clay – It refers to extremely fine clay particles (typically smaller than 2 micrometers down to 1 nano-meter) which remain permanently suspended in water and do not settle out under the force of gravity. When mixed with water, they form stable, gelatinous suspensions controlled by surface electrical charges rather than mass.
Colloidal fouling – It is the undesirable accumulation and deposition of fine suspended particles (ranging from 1 nano-meter to 1 micro-meter) on solid surfaces or within porous structures. Very frequently encountered in membrane filtration engineering, such as reverse osmosis (RO), and ultra-filtration (UF), it blocks pathways, builds resistive layers, and severely degrades system efficiency.
Colloidal graphite – It is a stable liquid suspension of ultra-fine graphite particles (ranging from 1 nano-meter to 1,000 nano-meters) uniformly dispersed in a carrier medium like water, oil, or alcohol.
Colloidal material – It is a heterogeneous system where microscopically small, insoluble particles (ranging from 1 nano-meter to 1,000 nano-meters) are evenly suspended in a continuous medium. These particles do not settle out under gravity and cannot be separated by standard filtration.
Colloidal metal – It refers to a stable two-phase dispersion system consisting of tiny metal particles (nano-crystals) with dimensions typically ranging from 1 nano-meter to 100 nano-meters homogeneously suspended within a continuous liquid medium. Since metal atoms naturally tend to aggregate and precipitate out of a solution, engineering these systems needs an outer layer of surface-bound ligands, surfactants, or polymers. This protective ‘capping agent’ creates electro-static or steric repulsion to prevent the nano-particles from agglomerating. Unlike bulk metals, colloidal metals show highly unique physico-chemical properties driven by finite-size and quantum effects.
Colloidal method – It is a cost-effective, bottom-up synthesis technique used to fabricate crystalline nano-materials and advanced ceramics. It involves forming, dispersing, and consolidating ultra-fine particles (ranging from 1 nano-meter to 1 micro-meter) within a continuous fluid solvent matrix. The main goal of this method is to precisely control nano-particle growth, size, and morphology while preventing agglomeration (clumping) to achieve a uniform, high-density micro-structure.
Colloidal model – It is a simplified representation of complex macro-molecules or particles (such as nano-particles) depicted as charged spheres or combinations of spheres to study their surface interactions and adsorption behaviours.
Colloidal nano-materials – These are stable or metastable dispersions of nano-scale particles (typically 1 nano-meter to 100 nano-meters) suspended in a fluid medium, controlled by thermodynamic, kinetic, and hydrodynamic forces.
Colloidal particle – It is an electrically charged small solid or liquid particle, typically ranging in size from around 1 nano-meter to 100 nano-meters, which are dispersed in a solvent within a colloidal solution.
Colloidal processing – It is a technique where fine or nano-particles are uniformly dispersed in a liquid solvent, shaped, and consolidated to build components with precise, flaw-free micro-structures. It is a wet-method approach used heavily in advanced ceramics, composites, and catalyst manufacturing.
Colloidal property – It refers to the distinct physical and chemical behaviours shown by a two-phase system where microscopic particles (the dispersed phase, sized between 1 nano-meter and 1 micro meter) are suspended throughout a continuous medium. Unlike true solutions (where solutes dissolve completely) or macro-suspensions (where particles settle out), the engineering performance of colloids is entirely governed by an exceptionally high surface-area-to-volume ratio and dominant interfacial surface phenomena rather than gravity.
Colloidal silica – It is a stable, liquid suspension of microscopic, amorphous (non-crystalline) silicon di-oxide (SiO2) nano-particles typically ranging from 1 nano-meter to 100 nano-meters in size.
Colloidal silica slurries – These are highly engineered fluid systems containing amorphous silicon di-oxide (SiO2) nan-particles uniformly dispersed in a liquid carrier. These slurries are important for applications needing atomic-scale planarization, micro-scratch reduction, and precision material binding. Since the particles range from 1 nano-meter to 100 nano-meters, they undergo Brownian motion, which keeps them suspended stably without settling out because of the gravity.
Colloidal suspension – It is a heterogeneous mixture where microscopically small, insoluble solid or liquid particles (ranging from 1 nano-meter to 1m000 nano-meters in size) are evenly dispersed within a continuous fluid medium. Unlike standard coarse suspensions, these dispersed particles do not settle out under gravity since they are kinetically stabilized by repulsive forces, such as = repulsion or steric hindrance.
Colonial finish – It is a surface finish achieved by selectively buffing an oxidized surface, hence producing lustrous highlights against the oxidized background.
Colonies – These are regions within prior-beta grains with alpha platelets having nearly identical orientations. In commercially pure titanium, colonies frequently have serrated boundaries. Colonies arise as transformation products during cooling from beta field at cooling rates which induce platelet nucleation and growth.
Colon operator (:) – It is a powerful syntax tool used to generate regularly spaced vectors, index arrays, and control loop iterations. It is a foundational feature in different programming languages. The operator serves three main functions in engineering workflows, namely vector creation, array indexing, and loop control.
Colorant – It is an additive substance, specifically a pigment or dye, used to modify the spectral reflectance or transmittance of materials like polymers, coatings, and composites to impart a specific color, opacity, or functional property.
Colorant pigment – It is a fine, solid, water-insoluble particulate substance mixed into a medium (like a resin, plastic, or coating) to provide colour, opacity, and light stability through wavelength-selective absorption and scattering.
Colorimeter – It is a device used in colorimetry which measures the absorbance of particular wave-lengths of light by a specific solution. It is normally used to determine the concentration of a known solute in a given solution by the application of the Beer–Lambert law, which states that the concentration of a solute is proportional to the absorbance.
Colorimetric analysis – It is a quantitative analytical technique used to determine the concentration of a substance in a liquid solution by measuring how much light it absorbs. It relies on the principle that colour intensity is directly tied to the concentration of the target chemical.
Colorimetric indicator – It is a reactive chemical substance, dye, or nano-material which changes colour visibly when it interacts with a specific physical or chemical stimulus, such as a change in pH, gas concentration, temperature, or chemical contamination.
Colorimetric sensor – It is an analytical device which detects and measures the presence or concentration of a target chemical, or physical analyte by producing a visible and measurable change in colour.
Colorimetric sensor arrays – These are low-cost, portable platforms which use grids of cross-responsive, chromogenic dyes to create distinct visual ‘finger-prints’ for chemical analytes.
Colorimetry – It is a quantitative analytical method used to determine the concentration of a substance in a solution by measuring how much light it absorbs. It relies on the rule that a solution’s colour depth matches its solute level.
Colour anodizing – In anodizing of aluminum, it is formation of a coloured coating on aluminum where the coloured compound, pigment, or dye is incorporated after the coating has been formed and prior to sealing.
Colour appearance – It is a specialized branch of colour science and optics which uses mathematical models to predict how humans perceive color under varying lighting and environmental conditions.
Colour appearance model – It is a mathematical framework which extends traditional colorimetry to predict how humans perceive colours under varying viewing environmental conditions. It is a model which includes predictors of at least the relative colour appearance attributes of lightness, chroma, and hue. To do this effectively, a colour appearance model (CAM) is to incorporate a chromatic adaptation transform (CAT).
Colour buffing – It consists of producing a final high lustre by buffing. It is the final stage of metal finishing which uses a soft wheel and a very fine compound to create a mirror-like shine.
Colour centre – It is a point lattice defect which produces optical absorption bands in an otherwise transparent crystal.
Colour channel – It is an independent data array which represents the intensity levels of a specific main colour component across an entire image. When these separate grayscale components are stacked together, they form a multi-dimensional matrix (tensor) which reproduces a full-colour image.
Colour-coated sheet – It is a factory-produced metal product made of a steel or aluminium base which is protected with a metallic anti-rust layer and finished with baked-on polymer paint.
Colour coating – It is the continuous, automated process of applying decorative and protective organic paint layers to metal substrates (typically steel or aluminum coils) before they are fabricated into finished products.
Colour coding – t refers to a standardized system of using distinct colours to visually convey specific information, categories, safety statuses, or material properties without relying on written text. This methodology acts as an important visual anchor to prevent human errors, streamline assembly and maintenance, and maintain strict work-place safety standards.
Colour combinations – These refer to the arrangement of different hues to create visual effects, such as striking, tranquil, or exciting schemes. These combinations can involve contrasts between warm and cool colours or the blending of vivid and dull shades to influence emotions and perceptions.
Colour compensation – It refers to a family of signal and image pre-processing techniques used to correct, reconstruct, or isolate overlapping or attenuated spectral data to restore true colour information or quantitative measurements.
Colour constancy – It is the algorithmic ability of a system to maintain a stable and consistent representation of an object’s surface colour despite changes in the intensity or spectral composition of ambient illumination.
Colour contrast penetrant – It refers to a highly visible dye (typically deep red) used in liquid penetrant testing (LPT), a popular non-destructive testing (NDT) method. This technique relies on capillary action to draw the low-viscosity fluid into surface-breaking flaws, which are then revealed against a contrasting background. It allows the inspection of components for cracks, pores, and weld discontinuities under normal white light or daylight conditions without needing specialized UV l(ultra-violet) lamps.
Colour correction – It is the technical process of maintaining consistency in colour information and minimizing distortions. It mathematically maps the raw colour data captured by an image sensor onto a standardized, accurate colour space, compensating for biases caused by specific light sources, lens properties, and hardware sensors.
Coloured cement – It is prepared by adding special types of pigments to the portland cement. The pigments added to the white cement (2 % to 10 % of the cement) when needed to get light colors, while it is added to ordinary portland cement when needed to get dark colors. The cement and the pigment are grinded together.
Colour development – It is the systematic process of creating, specifying, matching, and validating precise colour tones for materials, products, and components using technical standards and instrumental measurements.
Colour difference – It is a numerical representation of the difference between two colours, calculated using the square root of the sum of the squares of the differences in each colour axis.
Colour difference formula – It is a numerical metric used to measure the objective physical distance between two colours in a standardized colour space.
Coloured light – It is the electro-magnetic radiation within the visible spectrum (around 400 nano-meters to 700 nano-meters) which shows a dominant wave-length, causing it to be perceived as a distinct hue rather than a neutral gray or white. Unlike achromatic light (which is characterized solely by its intensity or luminance, like black-and-white signals), coloured light is quantitatively defined by three core physical and perceptual parameters namely hue (dominant wave-length), saturation (purity), and brightness (luminance).
Coloured noise – It refers to uncertainties which are dependent on their past states and show auto-correlation. It is generated by passing Gaussian white noise through a filter, resulting in a signal which has a correlation structure based on its previous values.
Coloured patch – It is a specialized surface treatment, material overlay, or digital visual tool used to mark, protect, or test specific areas of a component or system.
Coloured state – It is a condition in which a material, such as glass or an ionic crystal, shows colour because of the presence of colour centres, which are defects created by the absence of certain ions and the trapping of free electrons. These colour centres can be stable or unstable, affecting the material’s colouration and its response to excitation energy, such as irradiation.
Coloured stimulus – It is a physical light stimulus characterized by its spectral properties, which can be quantified using tristimulus coordinates to describe its appearance and magnitude of differences in colour.
Colour etching – It consists of immersing metallographic samples in specially formulated chemical etchants in order to produce a stable film on the sample surface. When viewed under an optical microscope, these surface films produce colours which correspond to the different phases in the alloy.
Colour fastness – It is the ability of a dyed or printed material to retain its original colour and resist fading or bleeding when exposed to external forces like washing, light, rubbing, or heat.
Colour fidelity – It is the degree to which a system or light source accurately reproduces the true colours of objects compared to a defined reference standard.
Colour filter – It is a device which transmits principally a predetermined range of wave-lengths.
Colour forecast – It is a data-driven prediction of future colour trends, palettes, finishes, and materials, typically projected 2 years to 5 years ahead to guide product development.
Colour forecasting – It is defined as the structured, data-driven process of predicting future colour trends, finishes, materials, and design combinations. Unlike purely intuitive forecasting, engineering-focused colour forecasting is highly analytical and typically projects outlooks 2 years to 5 years ahead to align with long manufacturing, tooling, and product development lifecycles. It serves as a critical bridge between material science, industrial design, and consumer psychology.
Colour gamut – It is the entire range of colours which a specific device or medium can accurately produce or record.
Colour generation – It refers to the physical and chemical processes which impart colour to materials by altering light. It occurs when an object changes the characteristics of light through mechanisms like emission, absorption, reflection, dispersion, scattering, or interference. Rat-er than relying purely on digital representations (like red, green, blue, or RGB values), engineering-level colour generation deals directly with the spectral power distribution of light sources and the structural properties of materials.
Colour indicator – It is a qualitative device or chemical substance which visibly changes colour to signal a specific chemical state, environmental condition, or reaction end-point.
Colouring – It consists of producing desired colours on metal surfaces by appropriate chemical or electro-chemical reaction. It is the finishing process, or combination of processes, which alters the appearance of a surface through coating, chemical, and / or mechanical operations.
Colourizers – These are formally classified as colouring agents or colourants. These are compounds formulated to permanently embed colour into plastics, textiles, and paints.
Colour management – It is the systematic engineering process of controlling, converting, and translating colour signals across different hardware, software, and physical materials to ensure accurate and predictable colour reproduction.
Colour matching – It is the systematic process of formulating, measuring, and adjusting colourants or digital outputs so that a product’s colour matches a specified reference target under standardized conditions.
Colour matrix – It is a linear transformation array (normally 3×3, 4×4, or 5×5) used to modify, balance, or convert pixel colour components and signals. In computer graphics, digital imaging, and video engineering, it multiplies colour vectors, such as RGBA (red, green, blue, and alpha) or XYZ values, to shift hues, adjust saturation, perform colour space conversions, or calibrate camera sensors.
Colour measurement – It is the objective, quantitative process of capturing and translating visual colour into precise numerical data using instruments like spectro-photometers and colorimeters.
Colour monitor – It is an output device which displays visual information and multi-coloured graphics by modulating light intensity across an array of red, green, and blue (RGB) sub-pixels.
Colour naming – It refers to the systematic use of common language terms or labels to identify specific regions of a colour space, bridging human visual perception with clear verbal or computational descriptions.
Colour order system – It is a logical framework and set of principles used to arrange and designate colours, frequently backed by physical material samples called colour atlases. Colour order systems are three-dimensional arrangements of colour based on appearance, where each colour is assigned, a notation corresponding to its position in the system. These systems frequently include an atlas of real samples to aid in color identification and are typically linked to perceptually uniform colour spaces.
Colour oxide – It is a material used to impart colour to a porcelain enamel.
Colour palette – It is a small, standardized set of colours used in software interfaces, technical drawings, and data visualizations to ensure visual consistency, reduce cognitive load, and accurately convey complex data.
Colour pyrometer – It is also known in engineering as a two-colour pyrometer or ratio pyrometer. It is a non-contact temperature-measuring instrument which determines an object’s temperature by calculating the ratio of radiation intensities emitted across two different narrow wave-length bands.
Colour quantization – It is the process of reducing the number of distinct u in an image while preserving its visual quality, frequently involving algorithms such as the median cut algorithm for effective colour representation.
Colour reproduction – It is the precise process of predicting, converting, and matching light spectra or pigments to accurately recreate original colours across different physical and digital devices.
Colour sample – It is a physical or digital reference standard used to evaluate, match, and control the exact colour and gloss characteristics of a material during manufacturing.
Colour sampling – It is a compression technique which reduces the colour data resolution of an image or video while keeping the brightness (lumen / luminance) resolution intact.
Colour selection – It refers to the systematic process of choosing, specifying, and standardizing colours based on established, uniform colour order systems. Unlike artistic colour choices, engineering colour selection relies on data-driven, repeatable frameworks to ensure safety, quality control, manufacturing consistency, and effective human-machine communication.
Colour signals – These signals refer to a system of light indicators which convey the status of equipment or conditions, using specific colours to denote different meanings e.g., green indicates normal operation, yellow signals caution, red warns of inoperability, and flashing red needs immediate action.
Colour sorting – It is also called optical sorting. It is the automated process of separating solid materials based on their colour, shade, or optical properties using high-speed sensors, cameras, and air ejectors. It is a critical automation technology widely used in industrial processing to ensure quality control, remove impurities, and grade products at high volumes. Colour sorting in scrap metal recycling is an automated or manual process which uses optical colour detection to identify, separate, and classify different metals based on their surface colour, hue, and visual finish.
Colour specification – It is the process of using standardized numerical colour models, physical targets, and instrumental measurements to define, communicate, and replicate exact colours across manufacturing and design pipeline.
Colour standard – It is a liquid solution of known chemical composition and concentration, and hence of known and standardized colour. It is used as a reference in the optical analysis of samples of unknown strength.
Colour stimuli – These stimuli refer to the specification of the optical stimulus characterized by operationally defined values, such as tristimulus values, luminance, and chromaticity, which include dominant wavelength and saturation.
Colour studies – These are simulations produced to explore and discuss options in colours and materials within architectural spaces, frequently incorporating perspectives at eye level and varying lighting conditions for effective presentation.
Colour temperature – It is the temperature in degrees Kelvin at which a black-body is to be operated for providing a colour equivalent to that of the source in question.
Colour test – It is the quantitative analysis of a substance by comparing the intensity of the colour produced when the substance is exposed to a reagent with a standard colour produced similarly in a solution of known strength.
Colour vision test – It is a standardized assessment used to evaluate an individual’s ability to distinguish and differentiate colours, shades, and hues. Within industrial, manufacturing, and technical fields, these tests are a critical quality control and safety protocol. They ensure that engineers, technicians, and inspectors can accurately interpret color-coded information.
Colour volume – It is the three-dimensional representation of a colour space which includes luminance (brightness) alongside chromaticity (hue and saturation). It defines the total range of colours a display device, sensor, or printing system can accurately reproduce across varying brightness levels.
Colpitts oscillator – It is an electronic oscillator which produces oscillations based on an LC (inductor-capacitor) circuit, utilizing two capacitors in series and an inductor to determine the oscillation frequency. It is characterized by a specific gain condition which is to be met for sustained oscillations, frequently analyzed using open-loop transfer functions.
Column – Column is defined as vertical load-bearing member supporting axial compressive loads chiefly. This structural member is used to transmit the load of the structure to the foundation. In reinforced concrete buildings beams, floors, and columns are cast monolithically.
Columnar array – It refers to a one-dimensional or two-dimensional alignment of components, materials, or data structures organized vertically into distinct columns or elongated arrangements. It also refers to a data layout where elements of the same column or field are stored contiguously in memory rather than by traditional row-by-row sequences.
Columnar crystals – These are elongated, highly oriented grains which grow in a specific direction opposite to the flow of heat during the solidification of molten metal.
Columnar dendrite – It is a multi-branched, tree-like metallic crystal structure which grows elongated and parallel to the direction of heat extraction during the solidification of metals and alloys. Unlike equiaxed dendrites, which grow radially from a central nucleus in an undercooled liquid, columnar dendrites grow as a single, aligned front away from a cool boundary (like a mould wall or a previous layer substrate) toward the hotter liquid melt.
Columnar-grain directionally solidified alloys – These are engineering materials with elongated, parallel crystal structures aligned deliberately along the main axis of heat extraction during solidification.
Columnar grains – These are elongated, vertically aligned crystal structures which grow directionally along the path of maximum heat extraction during the solidification of metals or vapour deposition. Unlike equiaxed grains, which are roughly spherical and randomly oriented, columnar grains have a high aspect ratio, meaning they are much longer in one direction than they are wide. [
Columnar structure – It is a coarse structure of parallel elongated grains formed by unidirectional growth, very frequently observed in castings, but sometimes seen in structures resulting from diffusional growth accompanied by a solid-state transformation.
Columnar-to-equiaxed transition – It is the microstructural change from long, directional (columnar) crystals to small, randomly oriented, spherical (equiaxed) crystals during metal solidification.
Columnar voids – These refer to a specific type of microstructural defect or elongated empty space characterized by a high aspect ratio, running parallel to the direction of material growth or deposition. Unlike the standard isotropic ‘interstitial voids’ found in basic crystal lattices (like tetrahedral or octahedral voids, which are pocket-sized and symmetric), columnar voids are elongated, channel-like cavities.
Column buckling – It is a sudden sideways bending failure of a slender structural member subjected to an axial compressive load, happening when the load passes a specific limit called the critical load. Unlike regular compression failure where the material breaks or crushes since the stress goes past its strength limit, buckling is an instability issue. It can happen even when the internal stress is much lower than the yield strength of the material.
Column cap – It is a structural widening, plate, or connector at the top of a vertical support column designed to safely transfer loads into and out of the member.
Column chromatography – It is a downstream separation and purification unit operation where a liquid mobile phase pumps a pressurized sample mixture through a packed solid stationary phase matrix inside a cylindrical column, isolating target compounds based on differential affinities, partition coefficients, or physical interactions.
Column confinement – It is a technique where a vertical compression member (typically a reinforced concrete or masonry column) is wrapped or bound laterally to restrain the internal concrete core from expanding sideways under axial loads. By preventing the lateral bulging (Poisson’s effect) and subsequent sudden crushing of the concrete, confinement transforms the material’s failure mode from brittle to highly ductile, considerably increasing its load-bearing capacity and energy dissipation during extreme events like earth-quakes.
Column connection – It is the critical structural joint which links a vertical column either to a horizontal beam (beam-to-column connection) or to another column section (column splice). Defined fundamentally as the intersection zone within the depth of the member framing into the column, its main purpose is to safely transfer internal forces, such as axial loads, shear forces, and bending moments, between structural members to maintain global stability and structural integrity.
Column degree – When dealing with structural analysis using the stiffness matrix method, ‘degree’ relates to the degrees of freedom (DoF) associated with a structural column. It defines the number of independent movements (displacements or rotations) which the joints of a column can undergo when subjected to external loading. In the context of linear multi-variable control systems and signal processing, a column degree represents the highest degree among the polynomial elements located within a specific column of a polynomial matrix.
Column diameter – It refers to the cross-sectional measurement of a vertical cylindrical component. In chemical processing, column diameter defines the internal width of a process vessel (such as a distillation, absorption, or stripping tower). It is the important geometric dimension which determines the fluid handling capacity of the vessel. It also refers to the outer dimension of a circular structural pillar. It is the main geometric dimension used to calculate the gross cross-sectional area of a round compression member. In analytical chemistry, column diameter refers to the internal diameter (ID) of a separation tube, e.g., HPLC (high-performance liquid chromatography) or GC (gas chromatography) columns). The internal cross-sectional width, usually measured in millimeters or micrometers.
Column experiment – It is a controlled laboratory study used to evaluate how fluids, gases, or contaminants travel through a porous medium (like soil, sand, or engineered resins).
Column flotation – It is a milling process, carried out in a tall cylindrical column, whereby valuable minerals are separated from gangue minerals based on their wettability properties.
Column joint – It is the critical zone of intersection where horizontal beams connect with vertical columns. It is specifically defined as the portion of the column within the depth of the deepest beam that frames into the column. Since it acts as the main hub for transferring complex stresses, including axial loads, bending moments, and shear forces, it is considered the most critical region for maintaining the structural integrity and stability of a building.
Column layout – Column layout reinforces the design and pattern of the columns of the whole structure. This plan is divided floor-wise and demarcates the exact size and distance between every column of the building. Column layout drawings further make it easier for the site engineers to make sense of the whole building layout.
Column matrix – It is defined as a matrix which contains exactly one column and any number of rows. Since its elements are stacked purely in a vertical arrangement, a column matrix with m rows has a mathematical dimensions or order of m × 1.
Column space – It is the set of all linear combinations of the columns of a matrix. It indicates whether a linear system has a solution by revealing the vectors which can be constructed from the matrix’s columns.
Column strength – It is the maximum axial compressive load a column can support before it undergoes structural failure. This structural element is important since it safely transfers forces from slabs and beams down to the foundation.
Column structure – It is a vertical load-bearing member which channels weight from slabs and beams safely down into the foundation.
Column sump – It is the lowest part or bottom chamber of a vertical industrial process container, such as a distillation column, scrubber, or reactor, where liquid collects before it is discharged, removed, or recycled.
Column sump pump – It is a type of vertical centrifugal pump designed to remove accumulated water or liquid from a sump pit, where the motor is positioned entirely above the pit on a structural column to protect it from moisture. The pump intake and impeller remain submerged at the bottom.
Column vector – It is a mathematical matrix which consists of a single vertical column of numbers. In linear algebra, a column vector with ‘m’ elements is formally defined as an m × 1 matrix (a matrix with ‘m’ rows and exactly 1 column)
Coma – It is a lens aberration occurring in the part of the image field which is some distance from the principal axis of the system. It results from different magnification in the different lens zones. Extra-axial object points appear as short, comet-like images, with the brighter small head toward the centre of the field (positive coma) or away from the centre (negative coma).
Comb drive actuator – It is a micro-electromechanical system (MEMS) device which uses electrostatic forces between interlocking, finger-like conductive teeth to create linear motion.
Comb filter – It is a signal processing circuit or algorithm which adds a delayed version of a signal to itself, creating a periodic frequency response with evenly spaced peaks and notches which look like the teeth of a comb.
Combination – It is a result or product of combining. It is a selection of items from a set which has distinct members, such that the order of selection does not matter. It is a mixture, result, or product formed by joining two or more things together.
Combinational logic circuit – It is a digital electronic circuit where the output depends exclusively on the current values of the inputs, with no memory, clock signal, or past state dependency.
Combination burner – It is a type of burner designed to combust different types of fuels, including both gaseous and liquid fuels. It can switch between using gas (like natural gas or propane) and liquid fuels (like oil) by adjusting its nozzles or other components. This flexibility allows it to adapt to varying fuel availability, cost, or environmental conditions. The defining feature of a combination burner is its ability to burn multiple fuels, typically gas and liquid fuels.
Combination dies – These are die-casting dies having two or more different cavities for different castings. The combination die can also be for forming.
Combination mill – It is an arrangement of a continuous mill for roughing and a guide mill or looping mill for shaping.
Combinatorial approach – It is a methodology which aims to considerably increase the rate of discovery and improvement of new compounds by synthesizing and screening thousands of different compositions in a single experiment. This approach is utilized across different materials issues, including optical, dielectric, and magnetic materials.
Combinational circuit – It is a module in digital circuits where the outputs are solely determined by the current inputs, without any memory of past inputs. The function of a combinational circuit can be described using a truth table or a Boolean equation.
Combined air – It refers to mixed air in HVAC (heating, ventilation and air conditioning) systems, which is the blend of fresh outdoor air and recirculated return air before it passes through heating or cooling coils.
Combined ash – It refers to the total solid residue produced by mixing fly ash and bottom ash after the combustion of a fuel source. It is very frequently referenced in the context of waste-to-energy (WTE) plants and municipal solid waste incinerators.
Combined axial compression – It refers to the simultaneous application of an axial compressive force (pushing along the longitudinal centre line) and a bending moment on a structural member. Members experiencing this type of dual loading are normally known as beam-columns.
Combined axial tension – It occurs when a structural member experiences a direct pulling force along its longitudinal axis combined with other forces or moments, such as bending moments or hydrostatic pressure.
Combined bearing – It is a specialized rolling bearing which supports both radial loads (perpendicular to the shaft) and axial loads (parallel to the shaft or side thrust) simultaneously within a single, compact assembly.
Combined bending – It refers to a structural member experiencing a bending moment alongside another simultaneous force or load, such as axial tension, compression (direct stress), shear, or torsion. Instead of analyzing a single type of stress, engineers use the superposition principle to add the individual stress components together to find the total internal stress.
Combined block foundations – These are similar to simple block foundation. They are used to support closely spaced equipments. Combined blocks are more difficult to design because of the combination of forces from two or more equipments and because of a possible lack of stiffness of a larger foundation base raft.
Combined blowing process – In the combined steel making process, oxygen needed to refine the steel is blown through the top mounted lance while the inert gas (nitrogen or argon) needed for the bottom stirring process is introduced into the melt through bottom stirring bricks for improving the process conditions by optimized mixing. The flow rate and type of stirring gas depends on the process phase and steel grade. A faster and better approaching of the metal slag equilibrium is achieved because of the bottom stirring. Equilibrium and mixing time depend on type, number, location of stirrers, and flow rate.
Combined carbon – It is the carbon in iron or steel which is combined chemically with other elements. It is not in the free state as graphite or temper carbon. It is the difference between the total carbon and the graphite carbon analyses.
Combined chlorine – It is the fraction of total chlorine which has chemically reacted with ammonia or organic nitrogen compounds to form chloramines.
Combined compressor – It is a mechanical setup which compresses gas in two or more sequential stages using intermediate cooling to achieve high final pressures efficiently.
Combined convection – It describes a heat transfer process where both forced and natural (free) convection mechanisms act together at comparable magnitudes.
Combined converter and vacuum units – The converter processes have one disadvantage in that stainless steels with very low carbon and nitrogen residuals are difficult to produce. The decarburization period is longer while chromium oxidation and argon consumption are increased as the desired carbon and nitrogen levels are decreased. Some steelmakers have tried to overcome this disadvantage by applying vacuum to the converter at the very late stages of the decarburization process. The concept was promoted by Leybould-Heraus as an alternative to argon oxygen decarburization (AOD) or vacuum oxygen decarburization (VOD). The concept of applying vacuum to a converter is being pursued by the installation of argon oxygen decarburization / vacuum converter refining (AOD / VCR) process. This process combines the advantages of argon oxygen decarburization and vacuum oxygen decarburization. This process is a low-oxygen decarburizing process wherein vacuum facilities are added to an argon oxygen decarburization furnace, and carbon content is decreased at low pressure utilizing oxygen solute in steel and oxides in slag without injecting oxygen, taking advantage of the strong stirring effect of the argon oxygen decarburization process.
Combined cooling, heating, and power system – It is defined as a tri-generation system which produces cooling energy alongside traditional combined heat and power (CHP) features, utilizing waste heat to power chillers for cooling during warm periods.
Combined cyanide – It is the cyanide of a metal-cyanide complex ion.
Combined cycle engine – It links two or more thermodynamic cycles in series, using the waste heat from a high-temperature ‘topping’ cycle to power a lower-temperature ‘bottoming’ cycle and greatly increase overall efficiency.
Combined cycle gas turbine – In combined cycle gas turbine plant, a gas turbine generator generates electricity and the waste heat is used to make steam to generate additional electricity through a steam turbine. This last step improves the efficiency of electricity generation.
Combined cycle gas turbine (CCGT) power plant – It is an advanced electricity generation facility which integrates a gas turbine and a steam turbine to capture waste heat and achieve high thermal efficiency.
Combined cycle power plant – It is a type of power plant which utilizes a combination of the Brayton cycle of a gas turbine and the Rankine cycle of a heat recovery steam generator (HRSG) to produce electricity, where the exhaust gas from the gas turbine serves as the working fluid to generate steam in the heat recovery steam generator.
Combined cycle unit – It is an electricity generation system which links a gas turbine (the Brayton cycle) and a steam turbine (the Rankine cycle) to capture waste heat and achieve high overall thermal efficiency.
Combined feed-back and feed-forward control – It is a strategy which pairs output-based error correction with anticipatory disturbance response to achieve fast and precise system regulation.
Combined flame – It refers to a hybrid combustion mechanism or flame structure which features characteristics of both premixed and diffusion flames, or a dual-action fire retardant set-up where simultaneous cooling, dilution, and ceramic-char formation occur.
Combined forging and ring rolling – It is frequently termed rolled ring forging. It is an incremental bulk metal-forming process which integrates open-die forging and mechanical rolling to manufacture high-strength, seamless metallic rings. In metallurgical terms, the process transforms a solid metal billet into a hollow, continuous torus (doughnut-shaped geometric surface) through controlled plastic deformation above the material’s recrystallization temperature, entirely eliminating casting defects, welding seams, and structural porosity.
Combined heading and extrusion – It is a cold-forging process which merges two distinct metal-forming operations into a single step. It creates a part with a large-diameter head and a long, hollow, or solid shank.
Combined heat and power (CHP) boiler – It is an integrated system which simultaneously produces electricity (or mechanical power) and useful thermal energy, such as steam or hot water, from a single fuel source.
Combined heat and power (CHP) plant – It is a facility which generates electricity and captures useful thermal energy at the same time from a single fuel source.
Combined heat and power (CHP) production – It is an energy generation approach which simultaneously produces electricity and useful thermal energy, considerably increasing energy efficiency and reducing environmental impact by utilizing energy which otherwise gets wasted.
Combined heat and power (CHP) system – It is a technology which produces electricity and thermal energy at high efficiencies using a range of technologies and fuels. With on-site power production, losses are minimized and heat, which otherwise is wasted, is applied to facility loads in the form of process heating, steam, hot water, or even chilled water. Combined heat and power equipment can provide resilient power 24/7 in the event of grid outages, and it can be paired with other distributed energy technologies like solar photovoltaics (PV) and energy storage. During conventional separate power and heat generation, nearly two-thirds of energy is wasted (discharged to the atmosphere) as heat during generation, transmission, and distribution. By capturing and using heat which otherwise is wasted and by avoiding distribution losses, combined heat and power can achieve efficiencies of over 80 %, compared to 50 % for typical technologies (e.g., conventional electricity generation and an on-site boiler). Because of this increased efficiency, combined heat and power systems can emit less carbon emissions than separate heat and grid power.
Combined heating and power systems – These are defined as energy systems which simultaneously produce electricity and heat, improving overall efficiency, reducing emissions, and improving cost-effectiveness compared to power-only plants.
Combined load transfer – It refers to the simultaneous transmission and redistribution of multiple types of forces, such as axial loads, bending moments, shear forces, and torsional moments, through a connected structural system or component down to the foundation.
Combined numerical profile (CNP) roll – It is an optimally shaped, geometrically contoured roll used in the work roll shifting systems of modern rolling mills (such as hot strip mills) to precisely control the shape, flatness, and thickness profile of sheet metal.
Combined patterns type wire rope construction – It has strand which is formed in a single operation using two or more of the above constructions. As an example, the wire rope can have a Seale construction in its first two layers and a Warrington construction in the third layer, and a Seale construction in the outer layer. The combined pattern type of wire rope construction is very superior in its fatigue resistance nature. It also has high flexibility and is superior in its wear resistance and hence has a wide range of uses.
Combined power generation cycle – It is an energy conversion system which integrates two or more thermodynamic cycles, typically a high-temperature gas turbine (Brayton cycle) and a lower-temperature steam turbine (Rankine cycle), in series to capture waste heat and dramatically increase overall electrical efficiency.
Combined severity factor – It is a single variable which merges reaction time, temperature, and acid concentration (pH) to model and optimize biomass hydrothermal pretreatment.
Combined sewer – It is an underground wastewater collection system that transports both domestic sanitary sewage and stormwater runoff through a single pipe network.
Combined shear – It refers to the state of stress where a material or component is simultaneously subjected to multiple distinct loading mechanisms which generate shear stresses on the same cross-sectional area. Instead of acting in isolation, these individual shear components are to be combined, frequently vectorially, to find the total resultant shear stress acting at a specific critical point.
Combined stacker and reclaimer – Combined stacker and reclaimer also known as stacker cum reclaimer can stack the material to form the stockpile or reclaim the stockpiled material and feed onto the main line conveyor. The stacker is mounted on the centre column, which allows rotation in both directions simultaneously with the vertical movement of the boom. Its height above the crest of the pile is kept at a minimum to reduce dust emission. Reclaiming takes place at the natural angle of slide. A raking harrow is mounted on the bridge reclaimer.
Combined stresses – These are those state-of-stresses which cannot be represented by a single component of stress, i.e., one that is these are more complicated than simple tension, compression, or shear. Combined stress occurs when two or more different types of mechanical loads act on a structural member or material at the same time, producing multiple types of stresses simultaneously. It alters how a material fails and needs specific evaluation criteria rather than looking at a single load type.
Combined technology – It refers to the integration of multiple processes, such as pyrolysis, gasification, and combustion, to produce energy or fuel, frequently resulting in products like gas tar and char.
Combined tension – It refers to a structural state where a member experiences a direct tensile (pulling) force simultaneously with other internal forces or moments, such as bending moments or hydrostatic pressures.
Combined vacuum – It is a method which integrates vacuum preloading with fill surcharge preloading, utilized when a surcharge load higher than the vacuum load is necessary for soil improvement and land reclamation.
Combined water – It is moisture which is chemically bound inside the crystal structure of minerals, rocks, soils, or chemical compounds. It forms part of the chemical makeup of a substance rather than sitting as free moisture. It does not evaporate easily and needs high heat to break free.
Combined wave – It is the resultant wave-form produced by the superposition of waves, where two or more individual waves overlap and their displacements add together at any given point in space and time.
Combiner – It is a device, circuit, or software function which merges multiple inputs or paths into a single unified output. Since engineering spans several sub-disciplines, the exact definition depends entirely on the context.
Combustibility – It is a chemical property measuring a material’s ability to ignite and sustain a flame in the presence of oxygen and a heat source. It defines how a substance reacts chemically with oxygen to release heat and light, changing into new substances like ash or gas.
Combustible components – These refer to the parts of a feedstock which can be burned to produce energy, specifically including volatile matter and fixed carbon, with fixed carbon providing the majority of the energy during smouldering.
Combustible gas – It is a gas which can ignite and burn when mixed with oxygen or an oxidizing agent in the presence of an ignition source.
Combustible-gas welding – It is normally called oxy-fuel or gas welding. It is a fusion-welding process which joins metals by melting their base surfaces using a high-temperature flame produced by burning a fuel gas mixed with oxygen.
Combustible loss – It is the loss representing the unliberated thermal energy occasioned by failure to oxidize completely some of the combustible matter in the fuel.
Combustibles – It is the heat producing constituents of a fuel.
Combustion – It is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, normally atmospheric oxygen, which produces oxidized, frequently gaseous products, in a mixture termed as smoke.
Combustion air – It is the air used in the combustion process. Air contains oxygen which is needed to combust fuel.
Combustion analysis – It is an analytical technique for determining the concentration of carbon and sulphur in samples. The sample is burned in a graphite crucible in the presence of oxygen, which causes carbon and sulphur to leave the sample as carbon dioxide and sulphur dioxide. These gases are then detected by infrared or thermal conductive means.
Combustion boiler – It is a type of boiler which uses the heat generated from burning fuel (like natural gas, oil, or coal) to heat water or produce steam. The combustion process, where a fuel reacts with an oxidant like oxygen to release heat, takes place within the boiler’s furnace. This heat is then transferred to the water contained within the boiler to raise its temperature.
Combustion chamber – A combustion chamber is the area within where the fuel / air mix is ignited.
Combustion data – It refers to the fundamental quantitative and qualitative information derived from chemical reactions, sensor readings, and simulations which describe thermodynamic properties, reaction kinetics, and fluid dynamics in burning systems.
Combustion-driven oscillation – It is a self-sustaining phenomenon where unsteady heat release from a flame couples with the acoustic pressure waves inside a confined combustion chamber, producing large-amplitude pulsations.
Combustion duration – It is the time interval, frequently measured in crank angle degrees , between the start of ignition and the end of the main burning process inside an engine cylinder.
Combustion efficiency – It refers to how effectively a fuel is burned to produce heat. It is measured by the percentage of the fuel’s energy which is converted into useful heat during combustion, while minimizing the production of harmful pollutants. In simpler terms, it is the ratio of the heat released by the fuel to the total heat input of the fuel. A high combustion efficiency means more of the fuel’s energy is used, and less is wasted as unburned fuel or wasted heat in the exhaust, In case of a burner, it is the effectiveness of the burner to completely burn the fuel. A well-designed burner operates with as little as 10 % to 20 % excess air, while converting all combustibles in the fuel to useful energy.
Combustion energy – It is the total heat energy released when a fuel undergoes a complete, exothermic chemical reaction with an oxidizer.
Combustion equipment – It refers to the machinery, device, or integrated system designed to burn fuel with an oxidizer (such as air) in a controlled way to convert chemical energy into heat, power, or mechanical work.
Combustion event – It is a controlled, rapid exothermic chemical reaction between a fuel and an oxidizer that releases thermal energy and rapidly increases pressure within a specific timeframe.
Combustion gases – Combustion gases are the hot gaseous products from the fire. These are also called ‘flue gases’ or ‘exhaust-gases’.
Combustion gas pass – One pass is the travel of the combustion gases once along the length of the boiler. If the gases are reversed and passed through another source of the boiler, this is a second pass.
Combustion head – It is the part of the burner which mixes the combustion supporting air with the fuel and stabilizes the flame which is generated. The components of the combustion head essentially are (i) the fuel metering device consisting of nozzles for liquid fuels and orifices and distributors for gaseous Fuels, (ii) the turbulator diffuser disk, which mixes the fuel and the combustion air, and stabilizes the flame to avoid it blowing back into the burner, (iii) the flame ignition system which uses electric arcs produced by high-voltage powered electrodes directly igniting the flame or coupled with a pilot burner, (iv) a flame sensor for motoring the flame, and (v) the flame tube made of profiled metal cylinder which defines the output speed range.
Combustion mode – It defines how a fuel and an oxidizer are mixed, structured, and ignited inside a thermal system or engine.
Combustion modelling – It is the use of mathematical and computer frameworks to simulate fuel-oxidizer chemical reactions, heat release, and fluid flow. It links basic laws of mass, energy, and momentum with chemical kinetics and thermodynamics.
Combustion product – It is a substance, gas, heat, or light created when a fuel reacts with an oxidizer during an oxidation process.
Combustion properties – These are quantitative and qualitative characteristics of a fuel-oxidizer mixture which define how it ignites, burns, releases heat, and propagates flames.
Combustion rate – It is the burning rate of the fuel, which measures how fast the fuel burns in terms of mass per hour / mass per minute. Coals with higher volatile matter has improved combustion rate.
Combustion stages – These refer to the sequential phases the fuel-air mixture undergoes inside an internal combustion engine (such as spark-ignition or compression-ignition engines) or the progressive burning in advanced propulsion systems like staged rocket and gas turbine combustors.
Combustion steam – It refers to water vapour generated by transferring thermal energy from the external combustion of a fuel (such as coal, natural gas, or biomass) into boiler feed-water.
Combustion temperature – It mainly refers to the adiabatic flame temperature, which is the maximum theoretical temperature reached when a fuel burns completely in an insulated system without any heat loss to the surroundings.
Combustion zone – It is the specific area within a furnace, engine, incinerator, or flame where fuel and oxygen actively mix and undergo rapid oxidation. This core reaction area produces high temperatures, heat energy, and combustion by-products like carbon di-oxide and water vapour.
Combustor – It is a component or flow duct in a gas turbine, ramjet, scramjet, or industrial system where fuel and high-pressure air are mixed and burned to produce high-temperature, rapidly expanding gases.
Comet tails – These are a group of comparatively deep unidirectional scratches which form adjacent to a micro-structural discontinuity during mechanical polishing. They have the general shape of a comet tail. Comet tails form only when a unidirectional motion is maintained between the surface being polished and the polishing cloth.
Comfort zone – It is the specific range of ambient temperatures, relative humidity levels, and air velocities where 80 % or more of building occupants feel thermal neutrality (neither too hot nor too cold).
Command and control – It refers to the socio-technical systems and frameworks which collect, synthesize, and communicate data to enable decision-makers to direct operations and implement control mechanisms in real time. A command-and-control system functions as the ‘nervous system’ of an operation, solving distributed decision-making problems under time pressure and uncertainty.
Command and control (CAC) approach – It is also called command and control regulation. It can be defined as the direct regulation of an industry or activity by legislation which states what is permitted and what is illegal. This approach differs from other regulatory techniques, e.g. the use of economic incentives, which frequently includes the use of taxes and subsidies as incentives for compliance. The ‘command’ is the presentation of quality standards / targets by a regulatory authority which are to be complied with. The ‘control’ part signifies the negative sanctions which can result from non-compliance. This approach encompasses a variety of methods for influencing behaviour through laws, incentives, threats, contracts and agreements.
Command and control server – It is the central server which manages and directs a botnet, facilitating communication and control of the infected devices.
Command and control system – It is an integrated framework of hardware, software, communication networks, and human roles which allows operators to gather data, make decisions, issue commands, and monitor operations in real time.
Command line interface – It refers to the systematic process of designing, structuring, and implementing text-based interfaces to ensure they are predictable, highly usable, and safe for automation. In software engineering, treating a command line interface (CLI) as a formal product, rather than a collection of ad-hoc scripts, demands strict adherence to standardized grammar, syntax patterns, and engineering principles.
Command path – It refers to the structured sequence or architectural route through which an instruction travels from its invocation source to its final execution target. In system administration and software engineering, a command path is a sequence of directory locations that an operating system’s command shell uses to search for executable files.
Command register – It is a specialized control register used by a host processor to send operational commands and direct the behaviour of a hardware device, peripheral controller, or sub-system.
Command response – It refers to how quickly and accurately a system follows, tracks, or reacts to a given input command.
Command sequence – It is an assembled, strict-order series of instructions or action steps contained in a control file or programme which software or hardware executes to perform automated processing.
Command surface – It typically refers to the explicit set of data, parameters, and operation rules used in computer-aided design (CAD) and civil engineering software to build, edit, and reconstruct a 3D geometric surface.
Command trajectory – It is the multi-disciplinary process of designing, calculating, and optimizing the physical paths and operational instructions which a guided system is to follow to achieve a specific mission objective.
Command window – It is an interface which provides information, allows users to enter commands at the command prompt, and offers greater control over tools compared to menus and toolbars. It includes access to command references found in the documentation folder for detailed instructions.
Comma-separated values – It is a simple, plain-text file format used to store and exchange tabular data, where rows are separated by line breaks and individual data fields within a row are separated by commas. In software engineering and data processing, it serves as a light-weight standard for moving structured data between different programs, databases, and architectures.
Commercial alloy – It is a standardized, mass-produced metallic mixture optimized for industrial manufacturing, combining a base metal with other metallic or non-metallic elements to achieve specific mechanical and chemical performance targets.
Commercial cement – It is a finely ground inorganic, hydraulic binder material produced on an industrial scale to satisfy global infrastructure and construction demands. When mixed with water, it undergoes a chemical process called hydration to form a paste which sets and hardens, binding aggregates like sand and gravel into durable structures like concrete and mortar.
Commercial customer – It is an organization, institution, or government entity which purchases technical systems, infrastructure services, or utility resources (such as power, gas, or software) for operational and profit-earning activities.
Commercial distribution – It refers to the curated network of lines, substations, and equipment which delivers electrical energy from high-voltage transmission grids down to commercial and industrial end-users.
Commercial energy – It is the energy sources which are available in the market-place with a specific price, including electricity, coal, and advanced petroleum products, used for electricity generation and different sectors such as industrial, and transportation.
Commercial energy consumption – It is the use of energy services in the service sector, which includes the electrical, heating, and cooling needs of buildings and structures, as well as infrastructure such as traffic lights and water systems. It is influenced by factors such as population growth and is projected to increase globally.
Commercial feasibility – It is an initial evaluation which determines whether a proposed technical project can generate enough financial return to justify its costs and market risks. It bridges the gap between raw technical capability (can it be built) and ultimate organizational viability (whether it is to be built it to make a profit).
Commercial glass – It is a manufactured amorphous inorganic solid, typically composed of silica sand, soda ash, and limestone, which is engineered and standardized to meet strict structural, thermal, safety, and performance requirements for large-scale architectural and industrial applications.
Commercially pure aluminum – It refers to unalloyed aluminum with a minimum purity level of 99 %. It contains minimal trace elements (mostly iron and silicon). Ithas very good flow when melted. It has h High volumetric shrinkage during solidification. It is highly prone to tearing while cooling.
Commercially pure copper – It is unalloyed copper containing a minimum copper content of 99.3 % to 99.9 % (with total impurities restricted to around 0.7 % or less), processed to maximize electrical and thermal conductivity, ductility, and corrosion resistance.
Commercially pure nickel – It is a refined metallic material containing a minimum of 99 % to 99.6 % nickel (frequently including trace quantities of naturally co-existing cobalt), with tiny residual limits of carbon, iron, manganese, silicon, and sulphur.
Commercial negotiation – It refers to the planning, reviewing, analysis and other activities which a buyer and seller conduct to reach an agreement. Negotiations frequently feature a series of intense discussions to secure a mutually beneficial agreement.
Commercial nickel catalyst – It is a nickel (Ni)-based heterogeneous material engineered for large-scale industrial chemical processes like steam reforming and hydrogenation, providing a low-cost, highly active alternative to expensive noble-metal catalysts.
Commercial off-the-shelf equipment – It refers to ready-made hardware, software, or systems which are mass-produced, commercially available to the general public, and used ‘as is’ without needing custom design or specialized manufacturing.
Commercial operation – It is the official point when a newly constructed plant, facility, or equipment finishes testing and begins regular, continuous operation to produce goods or deliver services for profit.
Commercial operator – It is mainly used in systems, and industrial fields; It is an individual or entity which runs equipment, vehicles, or facilities for financial compensation, hire, or profit rather than for private or non-commercial use.
Commercial power system – It is a localized electrical network designed to receive, distribute, and manage electricity within commercial facilities.
Commercial product – It sits at the intersection of organizational strategy and technical design. It is the structured, multi-disciplinary process of translating raw market opportunities and customer needs into concrete, legally compliant, and reproducible engineering requirements which can be manufactured at a profitable scale. It explicitly focuses on creating a viable commodity meant to be sold to the public.
Commercial quality – It refers to the characteristics of a product or service which make it suitable for sale and use in a commercial setting. It encompasses aspects like the product’s ability to be marketed, its inter-changeability with similar products, and its suitability for the intended purpose, while also satisfying customer expectations.
Commercial quality (CQ) steel – It is a general-purpose, low-carbon steel designation where only the chemical composition is guaranteed by standards, rather than specific mechanical properties like yield or tensile strength.
Commercial software – It is a computer programme produced, licensed, or sold for a profit or to serve a commercial purpose. It is developed explicitly to be marketed, licensed, or sold to end-users or organizations rather than created just for research or personal utility.
Commercial software package – It is a pre-written, proprietary application or suite developed for purchase or licensing to perform specific technical tasks like statistical analysis, computer-aided design (CAD), simulation, or experimental design.
Commercial supply chain – It is the integrated network of organizations, people, activities, information, and resources involved in moving a product or service from its original raw material suppliers through manufacturing and distribution to the end consumer.
Commercial vehicle – It is a motor vehicle designed, licensed, and built mainly for commercial operations, such as transporting heavy cargo, equipment, or multiple passengers, rather than personal travel.
Commingled yarns – These are defined as yarns created by combining thermoplastic matrix fibres with reinforcement fibres, which can be woven, knitted, or filament wound to form composite parts through heating and pressure.
Comminution – It is the breaking up or grinding an ore into small fragments. It also consists of reducing metal to powder by mechanical means. It is also the act of process of reduction of powder particle size, normally but not necessarily by grinding or milling.
Commissioning – It is the process of bringing new plant into operation.
Commissioning documentation – It refers to the complete set of records, procedures, test plans, and sign-offs which systematically verify and prove a facility or system meets the design intent and owner requirements before handover.
Commissioning documents – These refer to the technical documentation needed by the commissioning team to ensure effective project execution, including procedures, check-lists, manuals, and project-related files which are to be up-to-date and properly managed.
Commissioning engineer – Commissioning engineer is a technical professional who tests, inspects, and verifies that equipment, facilities, and systems in a new or renovated engineering project are installed correctly and perform safely as per the design and operational requirements before the plant is handed over for normal use.
Commissioning group – It is a multidisciplinary team tasked with managing, testing, and delivering a project’s systems to ensure they meet design specifications and operational readiness before handover.
Commissioning manager – Commissioning manager is the key project leader responsible for planning, scheduling, and overseeing the testing and start-up procedures needed to transition complex equipment and systems safely and efficiently from construction into active operation. Commissioning manager acts as the critical bridge between the plant design phase and final client handover. The manager verifies that all integrated mechanical, electrical, or industrial components meet strict design specifications, safety codes, and operational requirements.
Commissioning phase – It is the initial start-up period following the completion of plant construction, during which the plant’s systems are tested and checked against specified operating conditions to ensure proper performance and safety.
Commissioning process – It is a systematic quality-control process which verifies and documents that all systems, equipment, and infrastructure perform as per the owner’s project requirements (OPR) and design intent before a facility or plant becomes fully operational.
Commissioning team – It is a cross-functional group of professionals assembled to systematically test, verify, and document that a facility’s electrical, mechanical, and automation systems meet design intent and owner performance requirements before handover.
Commissioning test – It is a systematic quality-assurance procedure conducted after construction or installation to verify that equipment, sub-systems, and integrated systems operate safely, reliably, and as per the design specifications before being handed over for regular operation.
Committee for Mineral Reserves International Reporting Standards (CRIRSCO) template – The CRIRSCO international reporting template provides an international standard framework for public reporting of exploration results, mineral resources, and mineral reserves by mining and engineering professionals.
Commodity plastics – These are polymers such as polyethylene, polypropylene, and polyvinyl chloride which are used in high volume.
Commodity production – It refers to the large-scale, standardized manufacturing or extraction of uniform goods, such as raw materials, bulk chemicals, or standardized components, where units are completely interchangeable and compete mainly on cost and efficiency.
Common axis– It is a shared or central straight line around which two or more objects, parts, or systems rotate, revolve, or align. It is an imaginary or physical line of reference which passes through the centre of multiple components to maintain structural stability, symmetry, or coordinated motion.
Common boundary – It is the physical or legal borderline shared by two adjacent properties (excluding street frontages). It is also the conceptual or physical limit which separates a system of interest from its external environment or adjoining sub-systems. Common boundary is also :the mathematical constraints or physical rules applied at the edges of a computational domain to model interactions.
Common brass – It is a very widely used brass containing 63 % copper plus 37 % zinc. It is also known as basis brass and 63/37 yellow brass. It can be hot or cold worked. It has good ductility permitting cold heading of wire and rods and cold presswork but not deep drawing.
Common carrier – It is a public or private entity which offers transportation, pipeline, or utility services to the general public for a fee without discrimination.
Common cause analysis – It is an analytical technique used to identify recurring patterns, systemic vulnerabilities, or single events which trigger multiple failures or pooled safety incidents.
Common cause failure – It refers to situations where two or more component failures occur because of a shared cause, leading to multiple faults being triggered simultaneously. Common cause failures (CCFs) are substantial in redundant systems, since a single cause can undermine the reliability of all redundant components.
Common cause of failure – It is a dependent failure (quod vide, q.v.) of two or more (redundant) system elements due to a single cause, for example a fire or a flood.
Common causes – These are the causes which are normally present in a process giving rise to variations within limits.
Common control – It refers to a shared, centralized set of hardware, software, or logic components used to manage multiple sub-systems or loops instead of duplicating dedicated controllers for each individual part.
Common control channel – It is a shared telecommunications and networking link used to carry control and signaling information between network infrastructure (like a base station) and user devices before a dedicated connection is established.
Common effluent treatment plants – These are treatment systems specifically designed for collective treatment of effluent generated from small-scale industrial facilities in an industrial cluster. Individual effluent treatment plants (ETPs) normally face problems from lack of space, resources, capital cost, and specialized manpower for operation and maintenance, which are especially exacerbated for small-scale industrial facilities. These problems are reduced by collective treatment of effluent from a large number of small-scale facilities at a single site where the effluent undergoes similar treatment to what it would be subjected to individually. This helps in terms of land conservation, better treatment at one location, easy operation and maintenance, and shared expenses. Common effluent treatment plants are designed to collect and treat effluent from a multitude of facilities, which can also need common effluent treatment plants to deal with varying qualities and quantities of effluent.
Common impedance – It is a shared impedance section, such as a common ground wire or power supply trace, between two or more circuits where current flowing from one circuit develops an unwanted voltage drop which interferes with the other.
Common information model – It is a standardized, vendor-neutral data model used to describe physical and logical elements so diverse systems can share information seamlessly.
Common interferents – These refer to oxidizable species within a sample which can affect the accuracy of sensor readings. Their presence can lead to inaccurate measurements, necessitating methods to assess and mitigate their impact on sensor responses.
Common knowledge – It refers to foundational facts, standard practices, and technical concepts which are universally understood and accepted by professionals within the engineering field without needing a formal citation.
Common mode analysis – It is a systematic safety and reliability evaluation method used to identify vulnerabilities where a single, external root cause can simultaneously disable redundant or independent system channels.
Common mode choke – It is an electrical filter component with two or more identical windings on a shared magnetic core which blocks high-frequency common-mode noise while allowing differential-mode signals or direct current (DC) / low-frequency current to pass unaffected.
Common mode failure – It is the simultaneous or coincident failure of multiple redundant or independent components because of a single, shared root cause. Unlike normal independent failures where a back-up component seamlessly takes over if the main one breaks down, a ocmmon mode failure (CMF) defeats the purpose of system redundancy.
Common mode of failure – It is a dependent failure (q.v.) where two or more system elements fail in the same manner, for example by having the same incorrect maintenance action performed on all the elements.
Common-mode voltage – It is the average voltage present on both input terminals of a differential device or signal line with respect to a common reference point, normally ground.
Common pollutant – It is a widely recognized physical, chemical, or biological substance which exceeds safe concentration thresholds in the environment or indoor spaces, causing harm to human health or ecosystems.
Common search space – It is a pre-defined set of time-frequency resource locations where multiple user devices simultaneously monitor downlink control channels to receive network-wide control messages.
Common sense – It is a practical approach to building systems and products which prioritizes simplicity, flexibility, and evolutionary architecture over over-engineering or rigid perfection.
Common spatial pattern – It is a signal processing and feature extraction method used to maximize the variance difference between two classes of multi-channel data, very frequently in brain-computer interfaces (BCIs). Common spatial pattern (CSP) is a supervised spatial filtering technique which transforms multi-channel signals into a new coordinate space.
Common tangent – It is a straight line which touches two separate circular or curved parts, such as pulleys, gears, or rollers, at distinct points without crossing through them.
Common tangent construction – It has two main meanings depending on the discipline, namely a thermodynamic graphical method used to find phase equilibrium in material science, or a geometrical drawing technique used in mechanical engineering graphics to draw a line touching two separate circles.
Common time base – It is a synchronized reference time, such as ‘universal time coordinated’ (UTC), used by communication nodes to ensure consistent timing across a distributed system. It facilitates the coordination of data transfer and clock synchronization among multiple nodes within the system.
Communication – It is the process of sharing ideas, information, and messages with others in a particular time and place. It includes writing and talking, as well as non-verbal communication (such as facial expressions, body language, or gestures), visual communication (the use of images or pictures, such as painting, photography, video or film), and electronic communication (telephone calls, electronic mail, cable television, or satellite broadcasts). Two most common definitions of communication are (i) communication is sending and receiving of messages by means of symbols and in that context organizational communication is a key element of organizational climate, and (ii) communication is transfer of information from sender to receiver under the condition that the receiver understands the message. Communication is a process which is transactional (i.e., it involves two or more persons interacting within an environment) and symbolic (i.e., communication transactions ‘stand for’ other things, at various levels of abstraction).
Communication channel – It is the method used to transmit a message from a sender to a receiver. It is the pathway or medium through which information is shared. Examples include speaking, writing, visual signals, or electronic means like email or video conferencing. It is also the transmission path which facilitates communication between a transmitter and a receiver, and can consist of various media such as wire, coaxial cable, optical fibers, or free space. Communication channels can be classified as analog or digital, and further categorized based on their intended use, bit rate, and directionality (simplex, half-duplex, or full-duplex).
Communication end-point – It is an interface, node, or software location at the termination of a communication channel where data is sent, received, or processed.
Communication equipment – It refers to the physical hardware and integrated software used to transmit, receive, route, convert, and process analog or digital signals across telecommunication and data networks.
Communication graph – It is a mathematical model [G = (V, E)] where vertices (V) represent system entities like nodes, routers, or sensors, and edges (E) represent physical or wireless communication links between them.
Communication infrastructure – It is the integrated system of physical hardware, transmission media, and software protocols used to transmit data, voice, and video signals across networks.
Communication interface – It is the shared boundary, physical connection, and set of protocols which allows two or more independent systems, devices, or software components to exchange data and interact.
Communication link – It is the physical or logical transmission path which connects a sender (transmitter) and a receiver to transfer information, data, or control messages between systems.
Communication modes – These are also known as transmission or directional modes. These define the direction and timing of information flow between two connected devices over a communication channel.
Communication network – It is an inter-connected system of hardware nodes and transmission links designed to reliably exchange, route, and process data between devices.
Communication network domain – It is a distinctly managed section or operational sub-division of a larger telecommunications or computer network. It shares unified rules, protocols, security policies, or structural topologies.
Communication objective – It defines the specific, measurable target of transferring technical information, data, or system instructions accurately between a sender and a receiver. It ensures technical data, reports, or system parameters are conveyed without loss of meaning, ambiguity, or mis-interpretation.
Communication paradigm – It is a foundational framework or pattern of rules, models, and protocols which defines how information is exchanged between different entities in a system. It sets the rules for how data moves, requiring specific channel models, network topologies, and communication protocols. It provides basic building blocks to solve problems like reliably transmitting data at high speeds or storing it at high densities. New engineering domains, such as molecular communication in nano-networks or semantic communications, introduce entirely new paradigms which go beyond traditional electro-magnetic wave transmission.
Communication policy – It refers to a defined set of rules, protocols, and standards that govern how data, signals, or messages are transmitted between components, systems, or teams. In computer networks, distributed systems, and software engineering, a communication policy is the set of algorithms and procedures determining how different entities or nodes exchange data. In engineering organizations and teams, a communication policy is a structured guideline which outlines how technical information flows internally among developers, testers, and stakeholders, and externally with clients.
Communication port – It is a physical socket or logical endpoint which allows electronic devices and software programmes to send and receive data. It is a physical socket or connector on a device which acts as a gateway for electrical or optical data signals. It is also A virtual, numbered address within an operating system’s transport layer (ranging from 0 to 65,535) which identifies a specific application or service.
Communication process – It is a systematic exchange of information between a sender and a receiver, aiming to achieve understanding. It involves several key steps, including idea formation, message encoding, channel selection, message transmission, message decoding, and feed-back.
Communication processor – It is a specialized hardware controller or microprocessor designed to offload data transmission, protocol processing, and network management tasks from a main central processing unit (CPU).
Communication protocol – It is a standardized set of rules, formats, and procedures which govern how electronic devices and software systems transmit, receive, and interpret data.
Communication range – It is the distance over which sensors or devices can transmit data to one another, categorized into short range (typically 10 meters to 1,000 meters) and long range, with technologies such as LPWAN (low-power, wide-area network) enabling coverage of several kilometers.
Communications satellite – It is an artificial space-based radio relay station which receives, amplifies, and retransmits telecommunication signals across the curvature of the earth.
Communication service – It is a programmable, software-defined set of network capabilities which transmits, routes, and manages data, voice, or video streams between systems or users.
Communication session – It is a temporary, interactive, two-way connection between two or more communicating devices, programmes, or users which allows for the structured exchange of multiple messages.
Communications industry – It refers to the sector involved in the transmission of data and information through different technologies, including advancements in fibre optics and computer chips, which are expected to improve data transmission speeds and capabilities considerably.
Communication system – It is an organized collection of hardware, software, and channels designed to transfer information from a source to a destination.
Communication unit – It is a physical or logical component abstraction (comprising controllers, primitives, and interfaces) designed to transmit, receive, and process analog or digital information between different systems, nodes, or devices.
Community energy storage – It is a medium-to-large-scale localized storage system, typically a battery installation connected at the distribution grid level, which is shared by multiple residential or commercial users within a defined neighborhood or microgrid.
Community energy system – It is a localized network which integrates local energy conversion, transmission, storage, and consumption on a community scale. It uses distributed energy resources (DERs) like rooftop solar PV (photo voltaic), small wind turbines, geothermal, and combined heat and power (CHP) units.
Community renewable energy – It refers to decentralized renewable energy systems, such as solar arrays, wind turbines, or micro-grids, which are locally sited, managed, and collectively owned or shared by members of a specific geographic or municipal area.
Commutation angle – It is also called the overlap angle. It is the duration, measured in electrical degrees or radians, during which current transfers from one electronic switch (like a thyristor or silicon-controlled rectifier) to another, causing both devices to conduct at the same time.
Commutation failure – It is an adverse dynamic event in line-commutated converter (LCC) HVDC (high-voltage direct current) systems where a converter valve which is to turn off continues conducting instead of successfully transferring its current to the next valve in the firing sequence.
Commutation frequency – It is the rate at which electrical current is switched or reversed in motor windings or power electronic converters to maintain continuous rotation or proper power conversion.
Commutation relations – These refer to mathematical expressions which describe the incompatibility of certain observables, exemplified by the canonical commutation relations, where the commutation of position and momentum observables results in a specific constant. These relations are fundamental in quantum theory and highlight the concept of canonically conjugate observables.
Commutative diagram – It is a visual map, where following different directional paths between the same starting and ending points always results in the same final value or function.
Commutativity – It means that changing the order of operands or operations does not change the final result.
Commutator – It is a rotary electrical switch in certain types of electric motors and electrical generators which periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. Two or more electrical contacts called ‘brushes’ made of a soft conductive material like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature are connected to the commutator segments.
Commutator segment – It is an individual conductive metal block, typically made of copper, on a rotary electrical switch which connects stationary brushes to the revolving armature coils of a DC (direct current) motor or generator.
Co-Mo catalyst – It means cobalt-molybdenum catalyst. It is a bimetallic solid catalyst, typically composed of cobalt oxide and molybdenum tri-oxide supported on a high-surface-area alumina carrier. It is used to speed up chemical reactions like hydro-desulphurization (HDS).
Comodizing – It is a rust-proofing process for steel.
Comoving frame – It is a reference coordinate system attached to a moving object, or fluid element so that the specific entity remains locally stationary within that frame.
Compact – It is the object produced by the compression of metal powder, normally while confined in a die. It is also the operation or process of producing a compact, which is sometimes called pressing.
Compact convex subset – It is a set in a vector space which is simultaneously closed, bounded (compact), and contains the entire line segment between any two of its points (convex).
Compact crack arrest testing – It is a specialized fracture mechanics method used to measure a material’s ability to stop a rapidly running brittle crack.
Compact device – It is a piece of equipment or hardware designed with modified geometry to minimize size and volume while maximizing performance, energy efficiency, and cost-effectiveness.
Compact disc – it is a small plastic disc on which digital information is stored in the form of a pattern of metal-coated pits from which it can be read using laser light reflected off the disc.
Compact disc-read only memory – It is a type of read-only memory (ROM) consisting of a pre-pressed optical compact disc that contains data computers can read, but not write or erase.
Compact disc-recordable – It is a write-once, digital optical disc storage format that uses an organic dye layer to permanently record data.
Compacted graphite iron – It is the cast iron having a graphite shape intermediate between the flake form typical of gray cast iron and the spherical form of fully spherulitic ductile cast iron. An acceptable compacted graphite iron structure is one which contains no flake graphite, less than 20 % spheroidal graphite, and 80 % compacted graphite It is also known as compacted graphite iron or vermicular iron. Compacted graphite cast iron is produced in a manner similar to that for ductile cast iron, but using a technique which inhibits the formation of fully spherulitic graphite nodules.
Compacted sand – It is a cohesionless granular soil which has been mechanically densified through vibration or dynamic force to minimize air voids, increase dry density, and improve load-bearing capacity.
Compact exchangers – These are heat exchange units designed mainly for gas service, featuring large extended surfaces that allow for considerably higher heat transfer rates per unit volume compared to shell-and-tube constructions. They are characterized by small corrugation heights and thicknesses, enabling efficient operation in applications such as cryogenic services and high-temperature heat recovery.
Compact expression – It is a short, clear mathematical formula which summarizes a large or complicated set of variables and physical relationships. It simplifies long equations into a small, easy-to-read format. It is used in finite element analysis (a method for predicting how a part reacts to forces, heat, or vibration) to manage complex displacement and stress formulas.
Compact flange – It has been developed, using extensive testing and finite element analysis. This design is a smaller and lighter alternative to conventional flanges.
Compact fluorescent lamp – It is a fluorescent lamp which is which uses a tube that is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp. Compared to general-service incandescent lamps giving the same quantity of visible light, compact fluorescent lamps use one-fifth to one-third the electric power, and last eight to fifteen times longer. Like all fluorescent lamps, compact fluorescent lamps contain toxic mercury which complicates their disposal. The principle of operation remains the same as in other fluorescent lighting, i.e., electrons which are bound to mercury atoms are excited to states where they radiate ultra-violet light as they return to a lower energy level. This emitted ultra-violet light is converted into visible light as it strikes the fluorescent coating.
Compact heat exchanger – It is an energy-efficient device designed to maximize thermal transfer within a minimal footprint by using a high ratio of heat transfer surface area to volume.
Compact heat exchanger design – It is a configuration engineered to maximize heat transfer surface area relative to its overall volume, achieving a high surface area density typically higher than 700 square meter per cubic meter for gas-to-gas applications and 400 square meter per cubic meter for gas-to-liquid or liquid-to-gas systems.
Compactibility – It is the measure of how easily a material, such as soil, concrete, asphalt, or powder—can be compressed and densified to reduce air voids under an applied mechanical force.
Compacting – It is the process of compacting loose moulding sand by jolting, squeezing, shooting, air flowing and other ways during the moulding process to get the strength needed for sand mould.
Compacting concrete – It refers to a type of concrete which is engineered for improved properties in the fresh state, allowing it to flow and fill formwork under its own weight without segregation. It is characterized by key properties such as filling ability, passing ability, and segregation resistance.
Compacting factor test – It is a laboratory method used to measure the workability of fresh concrete by finding the ratio of the weight of partially compacted concrete to that of fully compacted concrete. It works best for low-to-medium workability mixes where standard slump tests are not accurate.
Compacting pressure – In powder metallurgy, it is the specific compacting force related to the area of contact with the press punch expressed in mega-pascals, or mega-newtons per square meter.
Compaction – It is the act of forcing particulate or granular material together (consolidation) under pressure or impact to yield a relatively dense mass or formed object. In powder metallurgy, it is the preparation of a compact or object produced by the compression of a powder, normally while confined in a die, with or without the inclusion of lubricants, binders, and so forth. Compaction can be done with or without the concurrent applications of heat.
Compaction characteristics – These characteristics refer to the specific mechanical and physical properties of a soil or material which dictate how it densifies under load.
Compaction control – It is the process of monitoring and testing soil or other construction materials on-site to ensure they are compressed to a specified density, moisture content, and stability.
Compaction cycle – It refers to the complete sequence of operations needed to compress a material, such as soil, asphalt, concrete, or powder, to increase its density and reduce its void ratio.
Compaction effect – It refers to the physical change which happens when mechanical pressure is applied to a material, such as soil, powder, or aggregate, forcing its particles closer together, expelling air voids, and increasing its overall density.
Compaction energy – It is the mechanical energy applied to a soil mass to rearrange its particles, expel air voids, and increase its dry density, shear strength, and load-bearing capacity. It is the quantity of work or mechanical input applied per unit volume of soil ‘E = (W.g.H.Nb.Nl)/V’, where ‘W’ is the rammer weight, ‘H’ is the drop height, ‘Nb’ is blows per layer, ‘Nl’ is the number of layers, and ‘V’ is the mould volume.
Compaction force – It is the mechanical force applied to a loose material, such as soil, powder, or granular aggregates, to reduce its volume by expelling air voids, rearranging particles, and increasing material density and structural strength.
Compaction model – It is a mathematical or physical framework used to predict how granular materials, soils, powders, or rock matrices reduce in volume and increase in density under applied mechanical or effective stress.
Compaction phase – It is a mechanical method of pressing particles closer together to increase material density and decrease air voids.
Compaction piles – These piles are driven into the loose granular soil for increasing the relative density. The bearing capacity of the soil is increased because of the densification caused by vibrations.
Compaction point – It refers to a specific location within a soil densification grid or pattern where a mechanical probe, weight, or compactive effort is applied to increase soil density and structural integrity.
Compaction pressure – It is the mechanical force applied per unit area to reduce void spaces, increase density, and improve the structural integrity of materials like soils, powders, and composites. It is calculated using the fundamental equation ‘pressure = force / area’.
Compaction process – It is a mechanism in which the solid matrix deforms to expel intergranular melt, involving either rearrangement of matrix grains without distortion (granular flow) or changes in grain shape through intracrystalline plasticity or diffusive transfer processes.
Compaction properties – These properties refer to the characteristics of soils that influence their maximum dry density (MDD) and optimum water content (OWC), and include relationships with parameters such as the plastic limit (PL).
Compaction ratio – It is a waste industry term. It is a proportion which refers to the volume of compacted waste which can be placed in the same storage space occupied by non-compacted waste. For example, a 3:1 ratio means that a compactor is able to reduce 3 cubic meters of loose waste down to 1 cubic meter of compacted waste.
Compactive effort – It is the quantity of mechanical energy applied to densify a soil mass by forcing out air voids.
Compact linear Fresnel reflector – It is a specific type of linear Fresnel reflector (LFR) technology. It is an advanced solar thermal concentration system which uses rows of long, flat or slightly curved mirrors to focus sunlight onto multiple fixed, elevated receivers.
Compact matrix – It is a shorthand or aggregated notation used to combine multiple individual matrices, channels, or system equations into a single, unified block matrix to simplify complex multi-variable analysis.
Compact mill – It refers to a highly efficient, space-saving manufacturing system designed to process materials, typically steel, paper, or minerals, within a considerably smaller physical footprint than traditional mills. The most common application is the compact strip production (CSP) mill (or compact steel mill), which revolutionized steelmaking by linking the continuous casting of thin slabs directly to the rolling mill, eliminating the need for massive reheating furnaces and separate, sprawling facilities.
Compactor – It is a heavy machine or device used to compress soil, gravel, asphalt, or waste by reducing air voids and increasing material density.
Compact prover – It is also called a small-volume prover. It is a measurement device used to calibrate and verify the accuracy of industrial flow meters without interrupting the normal flow of fluid.
Compact representation – It is a condensed, memory-efficient method of encoding complex data, system states, or mathematical models while preserving their essential functional characteristics.
CompactRIO – It is a rugged, modular real-time embedded control and data acquisition (DAQ) platform.
It is designed for demanding high-performance applications which need deterministic, real-time control, high-speed measurements, and specialized signal processing in harsh operational environments. Unlike standard programmable logic controllers (PLCs), which use sequential scan-based logic, a CompactRIO operates as a heterogeneous embedded computer with hardware-level loop rates and dedicated processing layers.
Compact shape – In compact shapes, the major three major dimensions of which (length, width, and height) are approximately equal. Complex shape is a shape in which all points on the boundary are as close as possible to the centre. The circle is the most compact two-dimensional shape since its boundary is everywhere equidistant from its centre point, and the length of its boundary (perimeter) relative to its area is also minimal.
Compact stand – It refers to a mill stand characterized by its smaller physical size and streamlined design, frequently designed for ease of maintenance and roll changes. These stands are normally sturdy and built to handle substantial loads, with features like adjustment screws and wear plates to ensure durability and long-term use.
Compact subset – It is a subset of a topological space which is itself compact, meaning that from every open covering of the subset, a finite open covering can be extracted. Additionally, a closed subset of a compact space is also compact.
Compact surface – It is a two-dimensional manifold where every open cover has a finite subcover, meaning it is finite in extent, closed, and can be constructed or triangulated using a finite number of patches or triangles.
Compact tension (CT) sample – It is a standardized, notched metal or plastic plate used in fracture mechanics to measure how well a material resists crack growth under stress.
Companion matrix – It is a square matrix whose structure and entries are formed directly from the coefficients of a monic polynomial, designed so that its characteristic and minimal polynomials equal that original polynomial.
Comparability – It is the verification which a system, component, or product remains functionally equivalent and safe after a manufacturing, design, or process change.
Comparative analysis – It is the systematic side-by-side evaluation of two or more designs, data sets, systems, or competitive products to determine their similarities, differences, strengths, and weaknesses.
Comparative experiment – It is a planned test which measures the performance differences between two or more systems, materials, or processes under the exact same conditions.
Comparator – It is a device which compares two physical or electrical inputs and outputs a signal indicating which one is larger or showing the dimensional difference between them.
Comparator circuit – It is an electronic device which compares two analog input voltages and outputs a binary digital signal (high or low) to indicate which input is larger.
Comparator input – It refers to a voltage input which allows one voltage to be compared with another, influencing the output bit based on the polarity of the input. It is often integrated into devices such as PICs (programmable logic controllers), which can utilize multiple inputs to trigger different output events.
Comparator output – It refers to the output voltage level of a comparator, which indicates a positive voltage value (logic 1) when the input voltage ‘V+’ is higher than the input voltage ‘V-‘, and a negative or zero voltage value (logic 0) when ‘V+’ is less than ‘V-‘.
Comparison – It is the systematic evaluation of two or more design options, materials, or methods against specific technical criteria, objectives, and constraints.
Comparison instructions – These are programming or processor commands which test two values to produce a Boolean result (true or false) or update status flags without changing the original data. These instructions evaluate relationships like equality, limits, or relative magnitude.
Comparison instruments – These instruments measure the unknown quantity by comparison with a standard. Examples of this category of instruments are direct current bridges and alternating current bridges.
Comparison of means – It is a statistical hypothesis-testing process used to determine if the average performance, measurement, or output of two or more groups or processes are considerably different from one another.
Comparison standard – It is a standard micrograph or a series of micrographs, normally taken at 75x to 100× magnifications. It is used to determine grain size by direct comparison with the image
Compartmental analysis – It is a mathematical modelling method which breaks a complex system down into a finite number of uniform inter-connected sub-systems (or compartments) to track how materials, energy, or information move through them over time.
Compartmentalization – It is the design practice of separating a system into isolated sections to stop failures, fires, or errors from spreading.
Compartmental modelling – It is a lumped-parameter mathematical approach which divides a complex system into a finite number of homogeneous, inter-connected zones or compartments to track mass, energy, or population flows over time.
Compartmental system – It is a lumped-parameter mathematical model which divides a complex physical system into a finite number of well-mixed, homogeneous units (compartments) connected by flows of mass, energy, or information.
Compartment fire – It a fire which occurs within a defined, enclosed space, such as a room or building, where combustion behaviour is heavily shaped by boundaries which trap heat, restrict oxygen, and cause radiative feed-back.
Compartment model – It is a lumped-parameter mathematical framework which divides a complex system into a finite number of homogeneous, well-mixed functional units (compartments) to track the transfer of mass, energy, or information over time.
Compatibility – It is the ability of entities to be used together under specific conditions to fulfill relevant requirements.
Compatibility effect – It is a concept where people react faster and more accurately when a physical response matches or fits a sensory stimulus.
Compatibility equations – – These are mathematical conditions which ensure a deformed material or structure remains continuous without forming internal gaps, overlaps, or voids.There are six differential equations which provide necessary and sufficient conditions to ensure the existence of a single-valued displacement field in the context of continuum mechanics, particularly when relating strains to displacements without material gaps or overlaps.
Compatibility (frictional) – In tribology, the materials which show good sliding behaviour, including resistance to adhesive wear, are termed frictionally compatible. However, it is to be noted that under some conditions materials which are not normally considered compatible in the metallurgical sense (e.g., silver and iron) can be very compatible in the frictional sense.
Compatibility (lubricant) – In tribology, it is a measure of the degree to which lubricants or lubricant components can be mixed without harmful effects such as formation of deposits.
Compatibility (metallurgical) – It is a measure of the extent to which materials are mutually soluble in the solid state.
Compatibility method – It is used to solve statically indeterminate structures by removing redundant supports to create a stable, statically determinate primary structure.
Compatibility standards – These are used to ensure that different parts or products fit together e.g. a plug fitting into a socket, nuts and bolts matching the thread etc. These are typically standards specifying requirements for size and design.
Compensated interpolation – It is an advanced signal-processing and computer-vision technique which estimates unknown intermediate values, such as missing pixels in a video frame, by tracking the physical trajectory of moving objects over time rather than just blending adjacent static values.
Compensating cations – These are positively charged ions which reside in inter-layer spaces or on surfaces of negatively charged mineral or polymer frameworks to maintain overall electrical neutrality.
Compensating eye-piece – It is an eye-piece designed for use with apochromatic objectives. They are also used to advantage with high-power (oil-immersion) achromatic objectives. Since apochromatic objectives are under-corrected chromatically, these eye-pieces are over-corrected. Hese eye-pieces are designed for use with objectives such as apochromats to correct chromatic aberration.
Compensating fibre – It is a specialty optical fibre engineered with large negative chromatic dispersion to cancel out the positive chromatic dispersion accumulated in standard transmission lines. As light pulses travel long distances through standard single-mode fibres (SMF), different wave-lengths or component frequencies spread out and broaden. Splicing a calculated length of dispersion-compensating fibre (DCF) into the link compresses these pulses back toward their original shapes.
Compensation – In a hydrostatic bearing, it is the use of flow resistances between the supply and the entry to the bearing.
Compensation chamber – It is a fluid or gas reservoir designed to regulate pressure, accommodate volumetric and thermal expansion, and maintain steady-state operations within thermal management or nuclear instrumentation systems.
Compensation network – It is a circuit used in inductive coupling systems to achieve resonance conditions, increasing the power transfer capability and efficiency between primary and secondary coils. It typically includes components such as capacitors designed to compensate for the total inductive reactance at the resonant frequency.
Compensation point – It refers to a specific operational, thermal, or electrical condition where opposing forces, signals, or energetic processes completely balance each other out, resulting in a net change of zero.
Compensation potential – It refers to the maximum capacity of a system, material, or network to correct, neutralize, or offset dimensional errors, energy losses, or dynamic deviations.
Compensation strategy – It defines the specific methods, pay structures, and incentives an organization uses to attract, reward, and retain technical talent while managing labour costs.
Compensation water – It is the controlled flow of water released from an impounding reservoir into the natural river bed downstream.
Competency – It is the measurable ability to apply specific knowledge, practical skills, and professional behaviours to successfully perform a job or a task.
Competent person – Competent person is someone who can identify existing and predictable work-place hazards and has the explicit authorization to take prompt corrective measures to eliminate them. : Competent person is also a mineral industry professional with relevant experience in the style of mineralization and deposit under consideration, registered with a professional organization, who takes responsibility for the public report.
Competent department – It is an authoritative body responsible for the planning, policy making, and implementation of measures related to specific sectors, such as distributed energy resources, ensuring compliance with relevant laws and regulations.
Competing process – It refers to alternative manufacturing methods or technologies evaluated against each other to produce a specific component or achieve a designated functional requirement.
Competing reaction – It is a type of parallel reaction where a single reactant is consumed through two or more simultaneous pathways to produce different products, typically one desired product and one or more unwanted by-products.
Competitive adsorption – It is the phenomenon where different components in a flooding system, such as DPG (dispersed particle gel) particles and surfactants, compete for adsorption sites on the negatively charged surfaces of rock particles, leading to differential migration velocities and chromatographic separation within porous media.
Competitive bidding – It is a normal practice for procurement which involves inviting multiple vendors to bid for the same material, product, or service per the requirements of the organization. It is normally opted by the organizations engaged in the large-scale procurement. Competitive bidding is done by way of tenders, request for proposal (RFP), and request for quotation (RFQ) etc., by the organization. The tender, request for proposal, or request for quotation is a document which details the requirements of the organization and invites vendors to participate in the competitive bidding process. The interested parties submit their proposals in response to the tender, request for proposal, or request for quotation within a specified timeframe.
Competitive growth – It refers to the phenomenon where dendrites with different crystallographic orientations outgrow one another during the solidification process in poly-crystalline materials, particularly favouring directions aligned with the maximum heat flow at the solid-liquid interface. This process leads to preferred growth patterns and the development of columnar structures, influenced by the local curvature of the melt pool boundary.
Complement arithmetic – It is a mathematical technique used to represent negative numbers and simplify subtraction by converting it into an addition operation. It reduces hardware complexity in computers and digital processors by allowing the same adder circuits to perform both addition and subtraction.
Complementary energy – It is a potential energy function defined in terms of stress fields (or applied loads) rather than strains or displacements.
Complementary energy method – It is a structural mechanics technique used to analyze internal forces, stresses, and deflections in static or statically indeterminate structures.
Complementary error function – it is denoted as ‘erfc(x)’, is a special mathematical function defined as ‘1 – erf(x)’, representing the integral of the Gaussian function from ‘x’ to infinity.
Complementary function – It is a step used in solving linear ordinary differential equations (ODEs) which model physical systems and circuits.
Complementary metal-oxide semi-conductor – It is an integrated circuit fabrication technology which uses symmetrical pairs of p-type and n-type field-effect transistors (metal-oxide-semi-conductor field-effect transistors, MOSFETs) to implement logic functions.
Complementary metal-oxide semi-conductor (CMOS) detector – It is a type of semi-conductor device which converts light into electrical signals, normally used in digital cameras and other imaging applications. It uses complementary pairs of p-type and n-type transistors (metal-oxide-semi-conductor field-effect transistors, MOSFETs) to form the detector elements, enabling efficient and low-power operation.
Complementary metal-oxide-semi-conductor (CMOS) device – It is a type of integrated circuit technology which uses symmetrical pairs of p-type and n-type semi-conductor transistors to perform logic functions with very low power consumption.
Complementary metal-oxide semi-conductor (CMOS) integrated circuits – These are defined as circuits which use complementary metal oxide semi-conductor technology, incorporating both n-channel and p-channel MOSFETs (metal-oxide-semi-conductor field-effect transistors), to achieve high-speed operation with low power consumption, making them particularly suitable for applications such as quartz watches.
Complementary metal-oxide semi-conductor (CMOS) technology – It is an integrated circuit manufacturing and design technology which uses symmetrical pairs of p-type and n-type field-effect transistors ((metal-oxide-semi-conductor field-effect transistors) to perform logic functions.
Complementary slackness conditions – These refer to the conditions which can be satisfied by setting either the slack variable to zero, indicating an active inequality, or the Lagrange multiplier for the inequality constraint to zero, which leads to distinct solution cases in optimization problems involving inequality constraints.
Complementary solution – It is the solution to a differential equation which describes the system behaviour in the absence of any input or excitation, representing the free response and typically vanishing over time because of the dissipation.
Complementary strain energy – It is a mathematical concept defined as the area above the stress-strain curve (or load-deflection curve), using stress (or load) as the independent variable.
Complementary technique – It typically refers to a secondary method or concept used alongside a main approach to fully capture a system’s behaviour, solve complex equations, or verify data from a different perspective.
Complementary variables – These variables refer to pairs of physical properties or system parameters linked by a trade-off or inverse relationship, meaning knowing or measuring one precisely limits the precision of the other.
Complete combustion – It is the complete oxidation of all the combustible constituents of a fuel.
Complete degradation – It refers to a material breaking down completely into safe, non-toxic, and non-destructive liquid or gas by-products.
Complete elliptic integral – It is a special class of definite integrals evaluated from ‘0’ to ‘pi/2’ which generalizes inverse trigonometric functions to solve complex non-linear problems like large-amplitude pendulums, magnetic fields, and ellipse arc lengths.
Complete fusion – It is the fusion which has occurred over the entire base material surfaces intended for welding and between all layers and weld beads.
Complete graph – It is a simple undirected graph in which every pair of distinct vertices is directly connected by a unique edge. It is normally denoted as ‘Kn’, where ’n’ represents the total number of vertices (nodes). If a people a network of devices where every single device has a direct, dedicated physical or logical link to every other device, they have a complete graph topology.
Complete joint penetration – It is also known as complete penetration. It is a penetration by weld metal for the full thickness of the base metal in a joint with a groove weld.
Complete miscibility – It is the ability of two or more substances to mix together in any proportion to form a single, uniform (homogeneous) solution without separating into distinct layers.
Complete model – It is a formalized, unambiguous representation of a system’s structure, behaviour, and physical properties which serves as the single source of truth for analysis, simulation, and manufacturing.
Complete Navier–Stokes equations – These equations refer to the full set of momentum and continuity equations which account for all relevant physical effects, including the influence of pressure gradients and viscous terms, in fluid dynamics scenarios. These equations provide a comprehensive description of fluid flow, as demonstrated in different studies analyzing velocity profiles under different initial conditions.
Completeness check – It is a formal quality-assurance process used to verify that a design, dataset, system requirement, or manufactured product contains all needed components, data fields, and specifications before approval or release.
Complete obstruction – It refers to a total physical or functional blockage within a system, such as a pipeline, or channel, which entirely halts the passage of fluid, gas, or material.
Complete oxidation – It is a chemical process which occurs when a fuel or substance reacts with an oxygen-to-carbon ratio which is at least stoichiometric, producing carbon di-oxide and water while releasing maximum energy.
Complete penetration – It is a weld condition where the weld metal completely fills the joint and fuses with the base metal across the entire thickness of the materials being joined.
Complete process – It is a sequence of processing steps performed by different sub plants, where each step executes a specific task on the raw material or product, ultimately delivering a finished product at the output of the last stage.
Complete separation – It is the process of entirely isolating specific components, particles, or pure substances from a mixture or slurry. It achieves 100 % purification or isolation of a target constituent, leaving no residual mixture or impurity in that specific isolated stream.
Complete shut-down – It is the total cessation of operations, power, or processes across a system, facility, or equipment, bringing it to a fully de-energized, isolated, and safe state.
Complete span – It refers to the exact geometric, structural, and mechanical parameters which describe the section of a conductor suspended between two consecutive supports (such as towers, poles, or pylons). Complete span is also the full combined distance from one outer end abutment to the other in multi-support structures like bridges.
Complete stiffness matrix – It is the assembled matrix which incorporates the stiffness sub-matrices of inclined members in a structure, transformed to refer to the main x-axis and y-axis, allowing for the analysis of structural behavior under joint displacements.
Complete visual inspection – It is a comprehensive, systematic examination of an object, component, or system’s entire surface and accessible internal features using the naked eye, optical aids, or remote tools to detect defects and verify compliance with standards. It is widely used in engineering, manufacturing, and non-destructive testing (NDT).
Complete wetting – It is a zero contact or dihedral angle of a phase at an interface.
Completion brine – It is a high-density, solids-free salt solution pumped into a wellbore during the completion or workover phase to control sub-surface pressure while protecting the reservoir formation from damage.
Completion design – It is the process of planning and equipping a drilled oil, gas, or injection well so it can produce or inject fluids safely and efficiently. It connects the underground reservoir to the surface facilities.
Completion drawing – This drawing is also known as record drawing or as-built drawing. There are bound to be certain variations, additions, or alterations as project progresses, because of unseen site conditions and advancement in technology. Howsoever small the variations, additions, or alterations can be, these are to be recorded on the completion drawings. Completion drawings are to be prepared simultaneously as the work proceeds.
Completion equipment – It refers to the permanent downhole and surface infrastructure installed in an oil or gas wellbore to safely, efficiently, and economically manage the flow of hydrocarbons from the reservoir to the surface. Unlike drilling tools, which are temporary assets used to create the wellbore, completion equipment remains in the well for its entire productive life.
Completion fluids – These refer to specialized fluids used during the well completion phase to improve well productivity by minimizing damage to the producing zone. These fluids, typically brines, are to be chemically compatible with the reservoir formation and are filtered to avoid introducing solids into the near-well-bore area.
Completion operations – These refer to the procedures conducted at the end of drilling to prepare the well for production by installing completion equipment. These operations involve the use of completion fluids to ensure safe and effective installation while managing downhole formation pressures.
Completion process – It refers to all operations which prepare a well for production, including the introduction of tubulars and equipment which facilitate the safe production or injection of fluids, as well as any necessary stimulation phases.
Complex amplitude – It is a single complex number which combines both the magnitude (peak size) and phase angle (initial shift) of a sinusoidal wave or oscillatory signal.
Complex arithmetic – It is the system of mathematical operations performed on complex numbers, numbers possessing both a real part and an imaginary part, used to simplify the analysis of alternating current (AC) circuits, oscillations, and wave signals.
Complexation – It is the formation of complex chemical species by the coordination of groups of atoms termed ligands to a central ion, commonly a metal ion. Generally, the ligand coordinates by providing a pair of electrons that forms an ionic or covalent bond to the central ion.
Complex coacervation – It is the separation into two liquid phases in colloidal systems, involving the interaction of two oppositely charged colloids, specifically a poly-anion and a poly-cation, both of which are water-soluble. This method is significantly influenced by the pH of the solution, as it determines the charge density on the ampholytes.
Complex conjugate – The complex conjugate of a complex number z = a + bi (or a + jb in engineering) is a – bi (or a – jb), formed by keeping the real part the same and changing the sign of the imaginary part.
Complex conjugation – It is an operation which keeps the real part of a complex number the same and flips the sign of the imaginary part. If a complex number in an engineering system is written as ‘z = a + jb’ (where ‘j’ or ‘i’ is the imaginary unit), its complex conjugate is denoted as ‘z* = a – jb’.
Complex dielectric constant – It is the vectorial sum of the dielectric constant and the loss factor.
Complex eigenvalue – It is a characteristic value L = a + ib derived from a system’s governing matrix equation which features both a real part (a) representing system damping or growth and an imaginary part (b) representing oscillatory or cyclic frequency.
Complex eigenvalue analysis – It is a mathematical method used to evaluate the stability and dynamic response of systems which contain damping, friction, or asymmetric stiffness matrices. It extracts complex eigenvalues (L = a + ib) from a system’s characteristic equation.
Complex event processing – It is a real-time data processing method which analyzes continuous streams of events to detect meaningful patterns, relationships, and dependencies across multiple sources. Instead of looking at individual signals or records in isolation, a CEP (complex event processing) engine evaluates data inside a moving time window, correlating causal, temporal, and spatial connections to trigger automated responses within milli-seconds.
Complex exponential – It refers to a signal which can be expressed as a combination of a decaying or growing sinusoidal wave and a complex number. It is fundamental in the Fourier representation of signals in computer science.
Complex exponential function – It is a signal or mathematical expression, where the amplitude and frequency components are complex numbers.
Complex exponents – These refer to mathematical expressions which involve exponential functions with complex numbers, which are used in the analysis of systems to capture frequency responses and behaviours, particularly within the context of linear systems.
Complex flow process – It is a manufacturing or physical system defined by multiple interacting variables, constraints, and dynamic pathways which need optimized control of mass, energy, and quality.
Complex fluid – It is a multiphase mixture, such as a suspension, emulsion, foam, or polymer solution, which appears uniform on a large scale but has a structured internal micro-structure on a microscopic or mesoscopic scale.
Complex frequency – It is a unified mathematical variable which combines exponential growth or decay with sinusoidal oscillation.
Complex frequency response function – It is the ratio of the displacement response, X(w), to the input force, F(w), in the frequency domain, expressed as H(w) = X(w) / F(ω), which characterizes how a system responds to harmonic excitation at different frequencies.
Complex hydride – It is complex metal hydride. It is a salt composed of a positively charged metal cation bound by ionic interaction to a complex negative anion, where hydrogen forms directional covalent or polar-covalent bonds with a central metal or metalloid atom.
Complex inclusions – These are non-metallic particles composed of more than one compound, like different oxides, oxide plus sulphide, or combinations of other elements. These inclusions are formed during steelmaking processes and can negatively impact the steel’s mechanical properties and overall quality.
Complexing agent – It is a substance which is an electron donor and which combines with a metal ion to form a soluble complex ion.
Complex instruction set computer – It is a computer processor architecture where single machine instructions can execute multi-step operations or combine memory access with arithmetic calculations.
Complex ion – It is an ion composed of two or more ions or radicals, both of which are capable or independent existence, for example, cupro-cyanide [Cu(CN)32-.
Complexions – It means equilibrium 2D state at an interface, characterized by an interfacial excess of chemical components and / or structural order parameters, at prescribed chemical potentials
Complexity – It characterizes the behaviour of a system or model whose components interact in multiple ways and follow local rules, leading to non-linearity, randomness, collective dynamics, hierarchy, and emergence. The term is generally used to characterize something with several parts where those parts interact with each other in multiple ways, culminating in a higher order of emergence higher than the sum of its parts. It also normally refers to the multi-component chemical makeup, intricate internal microstructures, and advanced thermal-mechanical processing needed to create modern high-performance alloys.
Complexity reduction – It is the process of simplifying intricate systems, product architectures, or design solution spaces to make them manageable, efficient, and robust without losing core functionality. It measures and minimizes the uncertainty or excessive components involved in meeting a system’s functional requirements.
Complex matrix – It is a rectangular array of numbers where at least one entry is a complex number (a + bi, combining real and imaginary parts).
Complex model – It is a sophisticated mathematical or digital representation of a system which features deeply inter-related, inter-dependent components rather than just a large number of independent input parameters.
Complex modulus – It is the stress-strain ratio of sinusoidal load on viscoelastic material, represented by M* = M’+ iM”, where ‘i’ is an imaginary unit. It can be measured under different stress conditions, including tensile, shear, volume compression, and longitudinal compression moduli.
Complex multi-axial stress – It is a state of stress where loads act simultaneously in multiple directions on a structural component, producing a combination of normal and shear stresses whose principal directions shift or rotate over time. Unlike simple uniaxial stress (which pulls or pushes in only one direction), a multiaxial state involves a 3D stress tensor with multiple non-zero components (Sx, Sy, Sz, Txy, etc.).
Complex network – It is a graph-based system of inter-connected components (nodes) and interactions (edges) featuring non-trivial topological traits, such as scale-free distributions, high clustering, or decentralized hubs. Which dictate collective system behaviour.
Complex ore – It is an ore containing a number of minerals of economic value. The term frequently implies that there are metallurgical difficulties in liberating and separating the valuable metals.
Complex parting line – It is a non-flat, multi-planar, or highly contoured physical boundary where separate mould segments or die halves meet. Unlike a simple straight or flat parting line which sits on a single geometric plane, complex parting lines step, curve, or angle across the component’s silhouette to accommodate intricate three-dimensional features, undercuts, or varying cross-sections without trapping the solidified metal. Since metallurgical components experience dramatic thermal expansion, high clamping forces, and fluid pressures, defining a complex parting line needs balancing multiple mechanical and metallurgical constraints.
Complex permittivity (e*) – It is a frequency-dependent material property which measures how a dielectric medium responds to an electric field by storing and dissipating electrical energy. It is mathematically expressed as e* = e’ – je”, where real part (e’)mrepresents the relative permittivity or dielectric constant, indicating the material’s capacity to store electrical energy through polarization, imaginary part (e”) represents the loss factor, indicating the energy dissipated as heat due to conduction and dipole relaxation friction.https://rfessentials.com/resources/rf-glossary/complex-permittivity/ In electromagnetics, using ‘e*’ simplifies Maxwell’s equations by combining displacement current and conduction losses into a single term.
Complex perovskites – These are materials with a multi-cation crystal structure based on the general formula ABO3 or A2BB’O6, where multiple different ions occupy the A-site or B-site lattices.
Complex phase – It is the design of advanced multi-phase micro-structures, such as in complex phase (CP) steels, to achieve high tensile strength combined with high formability.
Complex phase steels – Complex phase (CP) steels typify the transition to steel with very high ultimate tensile strengths. The microstructure of complex phase steels contains small amounts of martensite, retained austenite and pearlite within the ferrite / bainite matrix. An extreme grain refinement is created by retarded recrystallization or precipitation of micro alloying elements like titanium or niobium. In comparison with dual phase (DP) steels, complex phase steels show significantly higher yield strengths at equal tensile strengths of 800 mega-pascals and higher. Complex phase steels are characterized by high energy absorption and high residual deformation capacity.
Complex pole – It is a root of a system’s denominator polynomial (in a transfer function) which contains both real and imaginary parts, causing the system’s output to approach infinity at that frequency.
Complex process – It is an interconnected system of multiple variables, feedback loops, and non-linear steps where overall behaviour emerges from local interactions rather than a simple, predictable sequence. Unlike simple linear work-flows, complex processes feature branching paths, high sensitivity to initial conditions, and operational dependencies across multi-scale components (such as temperature, pressure, and chemical states).
Complex root – It is a solution to a characteristic or polynomial equation which contains both a real part and an imaginary part, written in the form z = a + bi.
Complex shear modulus – It is the vectorial sum of the shear modulus and the loss modulus. It measures a material’s overall resistance to continuous twisting or shearing deformation under dynamic, oscillating loads. The complex shear modulus applies to visco-elastic materials (such as polymers, and asphalt) which show both elastic (solid-like) and viscous (liquid-like) behaviours.
Complex silicate inclusions – It is a general term describing silicate inclusions containing visible constituents in addition to the silicate matrix. An example is corundum or spinel crystals occurring in a silicate matrix in steel.
Complex stress – It refers to a state where a material experiences both normal (direct) and shear stresses acting simultaneously across multiple planes because of the combined loading conditions (such as bending, torsion, and axial loads).
Complex stress intensity factor – It is a mathematical expression used in fracture mechanics to analyze combined opening (Mode I) and in-plane shearing (Mode II) stress states, specifically at the tips of complex or interface cracks.
Complex stress state – It refers to a condition where a material experiences a combination of multiple normal stresses and shear stresses simultaneously acting across different planes from multi-directional external loads.
Complex structure – It is a building, system, or component featuring intricate geometries, irregular load paths, or combined structural behaviours which deviate from standard design assumptions and need advanced analysis methods.
Complex system – It is a network of several interacting, autonomous, and diverse components whose collective behaviour produces emergence, global properties and patterns which cannot be predicted simply by analyzing the individual parts in isolation.
Complex variable – It is a mathematical variable, normally denoted as ‘z’, which can take on values of a complex number expressed in the rectangular form z = x + iy, where ‘x’ and ‘y’ are real variables (or numbers) and ‘i’ is the imaginary unit satisfying i-square = -1.
Complex vector – It is an element of a complex vector space, where the scalars used for vector operations are complex numbers rather than just real numbers. Complex vectors can be represented in spaces such as n-dimensional complex coordinate space, and they adhere to the same principles of linear independence, basis, and dimension as real vector spaces.
Complex velocity – It is the derivative of the complex potential function with respect to the spatial coordinate variable. It is written as W(z) = dF/dz = u – iv, where ‘u’ and ‘v’ are the horizontal and vertical physical velocity components of a two-dimensional flow.
Complex wavelet – It is a specialized waveform whose values are complex numbers (consisting of a real cosine-like part and an imaginary sine-like part) which allows for the simultaneous extraction of amplitude and phase information from a signal.
Complex work-piece – It is a metal part or raw component featuring intricate geometries, strict dimensional tolerances, and multi-axis features which cannot be easily produced using basic, single-step forming or standard 2-axis machining. These work-pieces typically possess features which fundamentally complicate both their physical shaping and their internal metallurgical characteristics.
Complex Young’s modulus – It is the vectorial sum of Young’s modulus and the loss modulus. It is analogous to the complex dielectric constant.
Compliance – In case of tensile compliance, it is the reciprocal of Young’s modulus. In case of shear compliance, it is the reciprocal of shear modulus. It is also, a term used in the evaluation of stiffness and deflection.
Compliance assessment – It is an activity undertaken to determine whether a regulated activity / operation complies with a statute, regulation, authorization or Code of Practice. Compliance assessments educate the organization on the statutory requirements and also identify present or potential non-compliance. Compliance assessments include inspections, reviews, and audits.
Compliance audit – It is a systematic evaluation of designs, processes, systems, and operational records to verify adherence to mandatory industry standards, safety codes, environmental laws, and internal technical policies.
Compliance check-list – It is a structured record and life-cycle management tool which maps technical, safety, and regulatory needs to specific verification methods, evidence documents, and sign-offs.
Compliance engineering – It is the practice of embedding regulatory, safety, and industry standards directly into technical systems, code, and product design workflows rather than relying on manual audits and paperwork.
Compliance mapping – It is the systematic process of linking technical controls, system configurations, and automated test logs directly to specific regulatory, legal, or governance requirements.
Compliance demonstration – It is the formal process of providing documented evidence, tests, calculations, or analyses to prove that a system, product, or component meets specified regulatory standards, safety criteria, or certification requirements.
Compliance matrix – It is a structured cross-reference table which maps every need from a solicitation, tender, or regulatory standard directly to the specific section of a technical response or design document where it is addressed. A compliance matrix can also refer to the mathematical matrix relating strain to stress, acting as the inverse of the stiffness matrix.
Compliance method – It is an experimental technique used to measure and track crack length inside a metal sample by monitoring changes in its structural flexibility under an applied load. It is also a structured procedure, technique, or standard set of rules used by an organization or individual to ensure adherence to external laws, industry regulations, or internal policies.
Compliance monitoring – It consists of the collection and evaluation of data, including self-monitoring reports, and verification to show whether pollutant concentrations and loads contained in regulated discharges are in compliance with the limits and conditions specified in the regulation.
Compliance schedule – It is a negotiated agreement between a polluting organization and the statutory authority which specifies dates and procedures by which the polluting organization is going to reduce emissions and, hence, comply with a regulation.
Compliance testing – It is a non-functional testing process which verifies whether a system, product, or process adheres to external laws, industry standards, or internal governance rules. Unlike functional testing which checks if a feature works, or performance testing which measures speed, compliance testing asks whether the system follows prescribed rules and produces verifiable audit evidence.
Compliant electrode – It is a stretchable, flexible electrical conductor which deforms without losing conductivity or restricting the movement of soft, deformable surfaces. It refers to electrodes used in dielectric actuator technology, typically made from conductive particles which can be easily applied as dust or paste on elastomer films, enabling high strains in dielectric elastomers.
Compliant mechanism – It is a flexible mechanical system which transfers or transforms force, energy, or motion through the elastic deformation of its members rather than relying solely on traditional rigid-body joints like pins, gears, or hinges.
Compliant substrate – It refers to an ultra-thin, soft, or flexible underlying base material (having a lower elastic modulus than the film or layer deposited on it) which deforms elastically to share strain, relieve lattice mismatch, or absorb mechanical loads.
Compliant tower – It is a tall, narrow, flexible offshore structure anchored to the seafloor which ‘gives’ or sways with dynamic wave and environmental loads rather than rigidly resisting them.
Compliant wall – It typically refers to a flexible boundary surface designed to move, flex, or deform in response to fluid or structural forces, thereby altering flow dynamics or reducing resonance.
Component – It is one of the elements or compounds used to define a chemical (or alloy) system, including all phases, in terms of the fewest substances possible. It is also one of the individual parts of a vector as referred to a system of coordinates. Also, it is an individual functional element in a physically independent body which cannot be further reduced or divided without destroying its stated function, for example, a resistor, capacitor, diode, or transistor.
Component analysis – It is a mathematical technique used to simplify complex data by reducing the number of variables while keeping the most important information. It is very frequently known as principal component analysis (PCA).
Component coating – It is a thin, continuous layer of material applied to the surface of a manufactured part to improve its physical, chemical, or aesthetic properties.
Component code – It is a standardized alphanumeric identifier used to track, maintain, and categorize specific assemblies, sub-assemblies, or hardware parts across work orders and asset management systems.
Component condition monitoring – It is the practice of tracking specific physical parameters of machine parts, such as vibration, temperature, and pressure, to detect wear or flaws before a breakdown happens.
Component design – It is the process of selecting materials and defining geometric shapes to ensure a manufactured part performs reliably under specific mechanical, thermal, and environmental loads. It bridges the gap between theoretical material science and practical mechanical engineering.
Component device – It is a foundational part, sub-assembly, or module which cannot typically perform a standalone function on its own, but serves as an essential building block when integrated into a larger system. Seismic component devices are innovative structural elements designed to protect bridges during extreme hazards, such as earthquakes, by absorbing or dissipating input external energy. Two of the most commonly used seismic component devices are seismic isolators and dampers.
Component drawing – A component drawing is mostly referred to as the drawing supplied by the manufacturer of the equipment. This kind of the drawing is complete with all the details of the component hence providing a detailed insight into its markings and different sub-parts. The component drawing provides detailed information about the nature and manufacture of a specific item incorporated on an assembly / layout drawing. It is a detailed drawing of a component for facilitating its production. All the principles of orthographic projection and the technique of graphic representation are followed to communicate the details in this drawing.
Component failure – It is the inability of an individual part to perform its needed total or degraded functions because of the damage, wear, or structural breakdown.
Component fibre – It is a specialized synthetic fibre extruded from two or more distinct polymeric or material components which remain separate and distinct in continuous longitudinal contact.
Component form – It refers to the representation of mathematical expressions, such as vectors or tensors, in terms of their individual components along specified coordinate axes, allowing for operations like differentiation and integration to be expressed in a manageable format.
Component, gas – Gas components refer to the individual gases present in a mixture, where each component exerts a pressure known as its partial pressure. The total pressure of the gas mixture is equal to the sum of the partial pressures of all gas components.
Component ground motion – It refers to the individual directional parts, specifically three orthogonal translational components (two horizontal and one vertical), into which seismic shaking of the earth’s surface is divided for structural analysis and design.
Component input – It refers to the specific data, energy, signals, or physical materials entering a system or discrete module to trigger a defined operation or system response.
Component leads – These are the conductive extensions of components on a printed circuit board which connect to the board’s joints and circuitry. These leads are to be trimmed to prevent short circuits when multiple components are inserted.
Component-level – It refers to the specific design, analysis, or management of an individual, modular building block, such as a software module, a hardware part, or a physical subsystem, which performs a distinct function within a larger system.
Component life-time – It is the operational duration or statistical length of time a part functions correctly before experiencing failure under specified environmental, electrical, and mechanical conditions. The target period a component is engineered to operate safely and effectively within its specifications before wear-out mechanisms (like fatigue or creep) take over.
Component material balance – It is an application of the law of conservation of mass which tracks a specific chemical species or element entering, leaving, reacting, or accumulating within a system, rather than tracking the total mass as a whole.
Component, metal – Metal components refer to structural elements made of metals which are valued for their strength, low cost, and ability to be machined to precise shapes and tolerances. They can be processed to improve characteristics such as stability, strength, and hardness, and are used in different applications including load cells and pressure transducers.
Component model – It is a framework or standard which defines how individual, self-contained parts (components) are designed, specified, and connected to form a larger system.
Component object model – It is a platform-independent, binary-level software standard which enables different application components to communicate and interact across programming languages, processes, and net-works.
Component phase – Component is the smallest number of independently variable chemical constituents, while a phase is a homogeneous portion of a system separated by a distinct boundary surface. Component phase is the phase of a component. For example, a water system has three phases (ice, water, vapour), but only one component (H2O).
Component set – It is a complete, grouped collection of individual parts, modules, or items needed to assemble, function, or test a specific device, system, or subsystem.
Component side – It is the main surface of a printed circuit board (PCB) where active and passive parts are mounted.
Component specification – It is a detailed technical document which defines the precise physical, material, functional, and performance requirements for a specific part or sub-assembly.
Component split – It refers to the specific fractions or phases of a mixture separated during a process, or the breakdown of manufacturing and product costs into distinct categories.
Component, split – Split components refer to the specific fractions of a mixture which are separated during a process, particularly focusing on the recovery percentages of heavy and light components in gas and liquid phases. These specifications can control the economic balance between gas and liquid, as well as limit the loss of light and heavy components.
Component testing – It is a method where individual, self-contained parts of an application are verified in complete isolation from the rest of the system. Also known as module or programme testing, its main goal is to ensure that a specific building block, such as a user interface button, a web form, or a backend microservice, functions perfectly on its own before it is linked with other parts of the application.
Component tolerance – Component tolerances refer to the allowable variability in dimensions of manufactured components, ensuring that despite inherent surface irregularities, the performance of assembled parts remains acceptable. This concept encompasses both the acceptable range of dimensions produced by manufacturing techniques and the variability in outputs of machines or processes.
Component value – It refers to optimizing the ratio of a part’s functional performance to its total life-cycle cost, ensuring it delivers required utility without unnecessary expense.
Component wave – It is an individual sinusoidal wave got by breaking down a complex, non-sinusoidal waveform or wave spectrum into its fundamental frequency and harmonic parts or discrete frequency bands.
Composite – It is a sample composed of two or more increments.
Composite action – It refers to the process where two or more distinct structural materials or components are bound together so securely that they act as a single, unified structural member rather than independent parts.
Composite application– It refers to a material or system engineered by combining two or more distinct constituent materials, a continuous matrix and a dispersed reinforcement, to achieve superior mechanical, thermal, or structural properties which the individual components cannot reach alone.
Composite beam – It is a structural element made by joining two or more different materials, very frequently a structural steel beam and a concrete floor slab, so they work together as a single unit to resist bending loads.
Composite bearing material – It is a solid material composed of a continuous or particulate solid lubricant dispersed throughout a load-bearing matrix to provide continuous replenishment of solid lubricant films as wear occurs, and effective heat transfer from the friction surface. However, it is to be noted that composite bearing materials need not only be self-lubricating, but can also be used for low wear, good frictional heat dissipation, or controlled frictional response (e.g., brake materials). Examples of composite materials are metal-matrix composites, laminated composites, filament-wound composites, and fiber-mineral-metal-filled composites.
Composite binder – It is a scientifically formulated blend of two or more distinct binding agents, typically combining organic, inorganic, or polymeric components, designed to achieve a balanced set of mechanical, thermal, and chemical properties which a single binder cannot provide alone.
Composite block – It in engineering is a modular building unit made by combining lightweight concrete or hollow blocks with high-efficiency insulation materials to provide structural strength and thermal insulation.
Composite bonding – It is a joining method which uses specialized structural adhesives to connect polymer matrix composite materials or join composites to dissimilar substrates like metals.
Composite bridge – It is a structural system where two or more distinct load-bearing materials, very frequently a reinforced concrete deck slab and structural steel girders, are mechanically connected to act together as a single, unified cross-section.
Composite building material – It is an engineered structural system formed by combining two or more distinct, physically and chemically separate constituents, typically a continuous matrix and a dispersed reinforcement or filler, at a macroscopic or microscopic level to achieve superior mechanical, thermal, or durability properties that the individual materials cannot provide alone.
Composite cements – These are cements in which a proportion of the Portland cement clinker is replaced by industrial by-products, such as granulated blast furnace slag and power station fly ash (also known as pulverized-fuel ash), certain types of volcanic material (natural pozzolanas) or limestone. The granulated blast furnace slag, fly ash and natural pozzolanas react with the hydration products of the Portland cement, producing additional hydrates, which make a positive contribution to concrete strength development and durability.
Composite ceramic electrolyte – It is a hybrid solid-state material made by combining an inorganic ceramic ion conductor with an organic polymer matrix.
Composite coating – It is a coating on a metal or non-metal which consists of two or more components, one of which is frequently particulate in form. Example is a cermet composite coating on a cemented carbide cutting tool. It is also known as multilayer coating.
Composite columns – These columns refer to structural elements which combine steel and concrete to utilize the favourable tensile and compressive characteristics of each material, resulting in improved strength, stability, and construction efficiency in buildings.
Composite compact – It is a metal powder compact consisting of two or more adhering layers, rings, or other shapes of different metals or alloys with each layer retaining its original identity.
Composite concrete – It is a multi-phase structural material created by combining a cementitious binder matrix with dispersed aggregates or high-strength reinforcing elements to overcome concrete’s inherent brittleness and low tensile strength.
Composite connection – It is a joint or interface mechanism that integrates different structural materials, very frequently steel and concrete, so they act as a single, unified structural unit under load.
Composite construction – It is a building method which combines two or more dissimilar materials, such as steel and concrete, so they act together as a single, cohesive structural unit. This approach maximizes each material’s unique mechanical benefits, like combining steel’s high tensile strength with concrete’s superior compressive strength.
Composite curves – These curves refer to graphical representations in heat recovery problems which show the thermal interactions between hot and cold streams in a process, where curves are adjusted by a specific temperature difference to analyze efficiency at the pinch point.
Composite cylinder – It is a structural or pressure-containing component made of two or more distinct, bonded material layers, typically combining high-strength reinforcing fibres (such as carbon, aramid, or fibre-glass) embedded in a polymer resin matrix, frequently wrapped over an inner metallic or plastic liner (the core).
Composite cylinder shell – It is a load-bearing, curved structural element with a tube-like geometry made from two or more combined materials, typically strong reinforcing fibres (like carbon or glass) embedded in a continuous polymer or resin matrix. It is a thin or moderately thick curved structural wall shaped like a cylinder, analyzed using specialized shell theories rather than flat-plate or simple 3D block mechanics.
Composite damage – It is any collection of irreversible, distributed changes and progressive structural flaws, such as matrix microcracking, fibre breakage, or layer delamination, caused by energy-dissipating physical or chemical processes under mechanical, thermal, or environmental loading.
Composite density – It is the total mass of a composite material divided by its total volume, typically calculated using the rule of mixtures. It is a property representing how tightly packed the mass is within a multi-phase material (such as a fibre-reinforced polymer made of a continuous matrix and a discontinuous reinforcement). Since the constituent materials remain physically distinct rather than dissolving into each other, the overall density is a combination of each component’s individual density and its proportional presence.
Composite diagram – It is a temperature-enthalpy representation which shows the thermal characteristics and heat transfer of hot and cold streams in a system. It allows for the estimation of enthalpy changes and the identification of energy targets, facilitating the optimization of heat exchanger networks.
Composite doubler – It is an external reinforcement patch made of advanced fibre-reinforced polymer materials (like boron-epoxy or carbon-epoxy) bonded to a structural component to repair damage, arrest fatigue cracks, and restore load-bearing capacity.
Composite electrode – It is a welding electrode made from two or more distinct components, at least one of which is filler metal. A composite electrode can exist in any of different physical forms, such as stranded wires, filled tubes, or covered wire.
Composite fibre – It is a high-performance structural material made by embedding strong, stiff fibres inside a continuous binding material called a matrix. In this combination, the individual materials do not dissolve or blend into each other, instead they stay separate and distinct while working together.
Composite floor – It is a floor system where a reinforced concrete slab and steel structural beams are connected mechanically to act together as a single, unified structural element.
Composite floor system – It is a construction method which utilizes steel beams connected with concrete floor slabs, combining the benefits of both materials to achieve a cost-effective building solution. This system frequently employs solid reinforced concrete or profiled metal deck floors with shear connectors to improve structural integrity.
Composite flywheel – It is a lightweight and strong energy storage device made from composite materials, offering superior specific energy compared to traditional metallic flywheels, while also contributing to the reduction of greenhouse gas emissions.
Composite gain – It refers to the overall closed-loop voltage or signal amplification achieved by combining two or more individual operational amplifiers or active stages into a single functional block.
Composite girder – It is a structural beam formed by connecting a steel (or sometimes concrete) main girder and a reinforced concrete deck slab so they act together as a single unit to resist loads.
Composite insulator – It is an advanced electrical insulating device used in high-voltage power transmission and distribution lines to support conductors and prevent unwanted current leakage to the ground, engineered by combining two or more distinct materials rather than using a single material like porcelain or glass.
Composite joint – It is a joint in which welding is used in conjunction with mechanical joining.
Composite laminated material – It is a structure made by stacking and bonding multiple thin layers (called plies or laminae) of fibre-reinforced composite materials together. Each individual layer consists of high-strength fibres embedded in a continuous resin or polymer matrix.
Composite machine – It is a tool or structural framework built using composite materials (such as carbon-fibre-reinforced polymers or polymer concrete) instead of traditional metals like cast iron or steel.
Composite micro-mechanics – It is the branch of engineering analysis which studies the mechanical behaviour of a composite material at the microscopic level of its individual constituents, such as the fibres, matrix, and their boundary interface.
Composite material – It is a combination of two or more materials (reinforcing elements, fillers, and composite matrix binder), differing in form or composition on a macroscale. The constituents retain their identities, that is, they do not dissolve or merge completely into one another although they act in concert. Normally, the components can be physically identified and show an interface between one another. Examples are cermets and metal-matrix composites.
Composite metals – These are also known as metal matrix composites (MMCs) or metal Composite materials (MCMs). These are combinations of at least two distinct constituent materials, where one is a metal acting as a continuous matrix and the other (metal or non-metal) acts as a reinforcement.
Composite nano-fibres – These are advanced one-dimensional nano-materials with diameters under 1,000 nano-meters which combine a continuous matrix material with reinforcing nano-scale additives (such as nano-particles, carbon nano-tubes, or polymer blends) to achieve superior mechanical, and electrical, or properties.
Composite nature – It means having a character or structure made up of distinct, varied parts or materials which remain separate while working together.
Composite panel – It is a structural element made of two thin, stiff outer skin layers bonded to a lightweight, low-density inner core. This configuration, frequently called a sandwich panel, allows engineers to maximize bending stiffness and strength-to-weight performance while keeping total mass to a minimum.
Composite patch – It is an advanced structural repair method which uses high-strength fibre-reinforced polymer materials bonded with structural adhesives over a damaged, cracked, or corroded area to restore load-carrying capacity.
Composite pile – It is made of two materials. A composite pile can consist of the lower portion of steel and the upper portion of cast in-situ concrete. It can also have the lower portion of timber below the permanent water table and the upper portion of the concrete. Since it is difficult to provide a proper joint between two dissimilar materials, composite piles are rarely used in practice.
Composite plate – It is an electrodeposit consisting of layers of at least two different compositions.
Composite ply – It is a single, individual layer of high-strength fibres (such as carbon, glass, or aramid) embedded within a continuous polymer or resin matrix, used as the fundamental building block for laminated composite structures.
Composite polymer electrolyte membrane – It is a semi-permeable solid or gel material made by combining an ion-conducting polymer with reinforcing fillers, porous supports, or nano-fibre frameworks. Engineering applications use these membranes to transport ions (like protons or lithium ions) between electrodes while blocking electrons and reactant gases.
Composite powder – It is a powder in which each particle consists of two or more different materials.
Composite preform – It is a pre-shaped arrangement of dry or partially bound reinforcing fibres (such as carbon, glass, or aramid) matched to the precise geometry of a final structural part before it is injected or infused with a liquid polymer resin.
Composite prepregs – These are fibre sheets which are impregnated with resin off-site and allowed to partially cure before being transported for application to structural elements. They typically need refrigeration to prevent curing prior to use and can be installed more quickly than traditional composite systems.
Composite pressure vessel – It is frequently called a composite overwrapped pressure vessel (COPV). It is a high-performance container built with an inner liner wrapped in a fibre-reinforced polymer matrix to safely store gases or liquids under extreme pressure.
Composite products – These products consist of (i) plate, sheet and strip clad with steels or alloys in order to resist wear, chemical corrosion or heat distortion with bonding which is normally achieved by rolling, and sometimes by spraying, welding or explosion, (ii) sandwich steel sheet formed from two sheets bonded together by means of a synthetic sound-insulating plastic layer, and (iii) sandwich panels fabricated from two ribbed sheets bonded by an insulating layer.
Composite repair – It is the method of restoring structural integrity and load-bearing capacity to damaged composite or metallic structures using fibre-reinforced polymer (FRP) materials. It is done by applying bonded fibre patches, precured layers, or wet lay-up systems (such as carbon or glass fibre in a polymer matrix) to reinforce a weakened or damaged area.
Composite ring – It is a structural or mechanical component made by combining two or more distinct materials (or individual rings) to achieve superior performance which no single material can provide on its own. By strategically bonding different materials, engineers can optimize the ring for conflicting requirements, such as high structural strength, light-weight properties, wear resistance, or thermal stability.
Composite rolls – These are specialized rolling mill components made by combining two or more distinct materials, such as an ultra-hard outer shell or ring bonded to a tough, ductile inner core or shaft.
Composites – These are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties that remain separate and distinct at the macroscopic scale within the finished structure.
Composite salt in a porous matrix – It is a hybrid material made by embedding a reactive inorganic salt (such as a halide or nitrate) inside the microscopic pores of an inert solid support (such as silica gel, activated carbon, or a metal-organic framework). It combines the physical adsorption properties of the porous host with the chemical hydration / dehydration energy of the embedded salt.
Composite sample – It is a single mixture created by combining multiple individual sample portions (called increments or aliquots) collected from different locations or times. This combined sample represents the average physical or chemical characteristics of a large, variable batch, material lot, or environmental stream.
Composite sandwich panel – It is a specialized structural three-layer composite made by bonding two thin, high-strength outer face sheets to a thick, lightweight, low-density inner core.
Composite service – It is an integrated assembly of multiple atomic (elementary) services or other composite services combined to form a higher-granularity, compound behaviour.
Composite shell – It is a thin, curved structural element made from multi-layered composite materials designed to efficiently carry loads through both membrane and bending forces.
Composite signal – It is a single signal made by combining two or more individual signals (components) of different frequencies, amplitudes, or information types so they can travel over one medium.
Composite solid electrolyte – It is an advanced solid ionic conductor made by mixing an ion-conducting polymer matrix with inorganic ceramic particles and lithium salts. This combination fixes the weak points of using just one material. Pure polymers bend easily and touch electrodes well, but they carry ions slowly at room temperature. Pure ceramics carry ions fast and resist heat, but they crack easily and form poor contacts with battery electrodes.
Composite specimens– These are fabricated structural elements made from materials such as woven roving fiberglass and epoxy, designed in specific shapes like corrugated or flat profiles for testing purposes. These specimens are created through techniques like hand layup and are subjected to curing before evaluation.
Composite stack – It is the ordered arrangement of individual fibre-reinforced composite layers (plies or laminae) bonded together to form a single structural laminate.
Composite steel t- It typically refers to a structural system where a steel profile and concrete work together as a single unit to maximize load-bearing performance.
Composite steel-concrete structure – It is a building or bridge system where structural steel and reinforced concrete components are inter-connected by mechanical shear connectors so that both materials act together as a single, unified cross-section.
Composite structure – It is a structural member (such as a panel, plate, pipe, or other shape) which is built up by bonding together two or more distinct components, each of which can be made of a metal, alloy, non-metal, or composite material. Examples of composite structures include honeycomb panels, clad plate, electrical contacts, sleeve bearings, carbide-tipped drills or lathe tools, and weldments constructed of two or more different alloys.
Composite structure diagram – It is a type of static structure diagram which shows the internal structure of a class and the collaborations which this structure makes possible. This diagram can include internal parts, ports through which the parts interact with each other or through which instances of the class interact with the parts and with the outside world, and connectors between parts or ports. A composite structure is a set of interconnected elements which collaborate at runtime to achieve some purpose. Each element has some defined role in the collaboration.
Composite super-structure – It is an upper part of a structure, very frequently on a bridge / building, built by combining two or more distinct materials (such as fibre-reinforced polymer composites, steel, and concrete) so they act as a single, unified load-bearing unit. This structure is a multi-material assembly designed to maximize the individual mechanical advantages of each component while minimizing their weaknesses.
Composite textiles – These are advanced materials made by combining a textile fibre structure with a binding matrix material to create a high-strength, lightweight structure. Textile composites are materials composed of textile reinforcements, such as yarns, combined with a binding matrix, typically polymeric, and are used for load-bearing applications across different industrial sectors.
Composite thickness – It is the total perpendicular distance measured through a multi-layered or multi-phase composite material, dictating its structural stiffness, burst pressure, and energy absorption.
Composite tow – It is an untwisted bundle of continuous reinforcing fibres, such as carbon, glass, or aramid, used as a building block to manufacture high-strength composite materials.
Composite video signal – It is an analog signal which combines brightness, colour, and timing information into a single channel transmitted over one wire.
Composite wall – It is a structural or thermal assembly made from two or more distinct materials or layers which work together to provide improved strength, thermal insulation, or protection.
Composition – It specifies the identity, arrangement, and ratio of the chemical elements making up a compound by way of chemical and atomic bonds. Chemical formulas can be used to describe the relative quantities of elements present in a compound.
Compositional analysis – It refers to the formal modelling and evaluation of complex computer networks by breaking them down into self-contained, modular components. Rather than analyzing a massive, global network state all at once (which causes a computational explosion), engineers analyze the properties of individual sub-units or layers and then mathematically ‘compose’ them to verify the behaviour, security, and performance of the entire system.
Compositional network architecture – It is a modern networking model where the internet and complex systems are built from flexible, self-contained, and reusable network modules rather than rigid, fixed hardware layers. This approach treats every individual network as a small ‘microcosm’ containing its own internal mechanisms.
Composition curve – It is a graphical representation showing the relationship between the chemical or material composition of a mixture (like a polymer blend or alloy) and its specific physical or mechanical properties.
Composition dependence – It refers to how a material’s physical, mechanical, or chemical properties change as its atomic, molecular, or phase makeup (composition) varies.
Composition interval – It refers to a series of defined intervals on a composition-interval diagram (CID), where each interval represents thermodynamically feasible mass transfer between rich streams and mass separation agents (MSAs). These intervals are numbered from top to bottom, allowing for the transfer of mass from a rich stream in one interval to any mass separation agent which lies in a lower interval. It represents a specific range of concentrations or compositions where thermodynamically feasible mass transfer can occur between process streams (such as rich contaminant streams) and mass separation agents (like solvents or adsorbents).
Composition measure – It is the quantitative representation of the relative quantities or fractions of different components making up a mixture, such as a gas or liquid stream.
Composition network – It refers to either a system-level networking methodology or a mathematical approach to circuit analysis.
Composition scale – It refers to the specific chemical make-up of mineral deposits, known as scale, which accumulate inside boilers, heat exchangers, and industrial pipes. It mainly include calcium sulphate, calcium carbonate, magnesium hydro-oxide, and, in some cases, silica or silicates, depending on the characteristics of the water supply and treatment processes.
Composting – It is the practice of mixing organic waste which can bio-degrade quickly to create a soil-like substance called compost that can be used for soil enrichment. It is a crumbly, earthy, sweet-smelling mixture of decomposing organic matter (e.g., leaves, food scraps) which is created in a controlled, thermophilic environment. It is frequently used to improve the texture, water-retaining capacity, and aeration of soil.
Composting piles – These poles refer to structured heaps of organic waste materials which undergo a decomposition process facilitated by micro-organisms, heat, and moisture, ultimately transforming the waste into valuable soil amendments.
Composting process – It is a controlled, aerobic biological treatment method where micro-organisms break down bio-degradable organic waste into a stable, pathogen-free, and nutrient-rich soil amendment.
Compound – It is the intimate admixture of a polymer with other ingredients, such as fillers, softeners, plasticizers, reinforcement, catalysts, pigments, or dyes. It is also a thermoset compound normally contains all the ingredients necessary for the finished product, while a thermoplastic compound can need subsequent addition of pigments, blowing agents, and so forth. A chemical compound is a chemical substance composed of many identical molecules containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound.
Compound annual growth rate – It is the mean annual growth rate of a value over a specific time period, normally expressed in percentage terms. It is particularly useful for calculating the rate of increase in contexts such as production, user engagement on social sites and is most stable during periods of exponential growth.
Compound compact – It is a powder metallurgy compact consisting of mixed metals, the particles of which are joined by pressing or sintering, or both, with each metal particle retaining substantially its original composition.
Compound die – It is a die which is designed to perform more than one operation on a part with one stroke of the press, such as blanking and piercing, in which all functions are performed simultaneously within the confines of the blank size being worked.
Compound interest – It is interest calculated on the initial principal and all previously accumulated interest from past periods. Unlike simple interest (which only pays based on the starting amount), compound interest adds earned interest back into the balance. Each new cycle calculates returns on a larger total, making your money grow faster over time.
Compound parabolic collector – It is also called a compound parabolic concentrator or Winston-type collector. It is a non-imaging solar thermal collector built from two symmetrical parabolic reflector segments which direct incoming radiation onto a smaller receiver. It is a solar thermal collector designed to concentrate and reflect all incident radiation onto a receiver, characterized by low concentration and the ability to accept both direct normal and diffuse radiation within a specific acceptance angle.
Compound parabolic concentrator – It is a non-imaging optical device which uses two symmetrical parabolic reflector segments to collect light from a wide entrance aperture and concentrate it onto a smaller receiver.
Compound photo-voltaics – These refer to solar energy conversion technologies which use compound semi-conductor materials, such as cadmium telluride (CdTe), gallium arsenide (GaAs), or copper indium gallium selenide (CIGS), to directly convert sunlight into direct-current (DC) electricity through the photo-voltaic effect.
Compound process – It typically refers to a manufacturing or machining technique which combines two or more distinct processes or mechanisms into a single operation to overcome the limitations of using a single method.
Compound semi-conductor – It is an electronic material made from two or more different chemical elements combined together, unlike single-element semiconductors like silicon.
Compound semi-conductor device – It is an electronic component made from crystalline materials composed of two or more chemical elements from different groups of the periodic table, such as gallium arsenide (GaAs) or gallium nitride (GaN).
Compound structure – It is a complex load-bearing system which combines two or more distinct structural action types, such as members subjected to axial loads (like trusses) and members subjected to bending moments and shear forces (like beams and frames), to resist external loads more efficiently than either system can resist alone.
Compound uptake – It refers to the rate or process by which a system, material, or organism absorbs, internalizes, or captures a specific chemical compound from its surrounding environment.
Compound zone – It is the surface layer of diffusion-treated steels, which is made up of inter-metallic compounds such as nitrides or carbides.
Comprehensive mathematical model – It is an abstract, quantitative representation of a physical system or process which uses variables, equations, and logical relations to analyze, simulate, and optimize behaviour.
Comprehensive microstructural investigation – It is the systematic, multi-scale analysis of a metal or alloy’s internal structure to understand how its microscopic features dictate its overall mechanical and physical properties. It moves beyond basic imaging to evaluate the size, shape, orientation, and chemical composition of the material’s constituent phases, grains, and defects.
Comprehensive test – It is an in-depth evaluation. It is a detailed document which specifies the requirements, methods, pass / fail criteria, and expected outcomes for evaluating a system, component, or material.
Comprehensive testing – It is a systematic strategy which evaluates all functional and internal structural components of a system to ensure total quality, reliability, and performance.
Comprehensive theory – It is a complete set of proven rules and math models used to design, test, and build safe systems. It is a unifying framework which effectively integrates different experimental observations and analyses.
Comprehensive treatment – It refers to the combination of multiple methods to effectively and efficiently treat leachates from landfills, minimizing complexity and overcoming the drawbacks of separate treatments. It involves considering the efficacy, expense, and environmental impact of the purification process.
Compressed air – It is the air which is kept under a pressure having a value higher than the atmospheric pressure (0.1 mega-pascals). It is a medium that carries potential energy. It is a widely used utility in a steel plant. It is an important source of instrument air. Other than instrumentation air which is completely dry and free from contaminants, there are the three main uses of compressed air in a steel plant namely (i) blast air for blast furnace, (ii) for the production of oxygen, nitrogen and argon in an air separation plant, and (iii) a utility gas with several uses. Major among these is the operation of pneumatic devices.
Compressed air energy storage – It is a mechanical system which uses surplus or off-peak electricity to compress ambient air and store it under high pressure in underground caverns or above-ground tanks, releasing it later through expansion turbines to generate electricity during peak demand.
Compressed air energy storage (CAES) system – It is a technology which converts surplus electrical energy into potential energy by compressing ambient air and storing it in underground caverns or high-pressure tanks for later power generation.
Compressed air motor – It is a mechanical device which converts the potential energy of compressed air into useful kinetic work through linear or rotary motion.
Compressed bit-stream – It is a sequence of digitally encoded, size-reduced data designed for fast storage, memory savings, and efficient transmission. In digital media and tele-communications, It is an encoded stream of audio, video, or image data processed through compression algorithms to lower band-width needs while preserving acceptable quality. In hardware and field programmable gate array (FPGA) configuration, it is a compacted binary file containing initialization and logic configuration data for programmable integrated circuits like field programmable gate arrays.
Compressed data – It refers to data which has been reduced in size through data compression techniques, which can be either lossless or lossy, to facilitate faster transmission and reduced storage space.
Compressed earth block – It is a sustainable masonry building material made by mechanically pressing a damp mixture of inorganic subsoil, sand, silt, and non-expansive clay at high pressures without firing.
Compressed file – It is a digital file reduced in size using mathematical algorithms which remove redundant data or encode information more efficiently.
Compressed gas – It is a material or mixture inside a container with an absolute pressure exceeding 0.28 mega-pascals at 20 deg C, or an absolute pressure exceeding 0.72 mega-pascals at 55 deg C, as well as any flammable liquid with a vapour pressure exceeding 0.28 mega-pascals absolute at 38 deg C.
Compressed gaseous hydrogen – It is a method of storing hydrogen gas at high pressures, typically ranging from 35 mega-pascals to 70 mega-pascals, or up to 90 mega-pascals to 100 mega-pascals at refueling stations, to overcome its extremely low volumetric energy density at ambient conditions.
Compressed hydrogen – It is the physical storage and containment of gaseous hydrogen under high pressures, typically ranging from 35 mega-pascals to 70 mega-pascals or higher, inside specialized pressure vessels.
Compressed hydrogen storage – It is the physical containment of hydrogen gas at high pressures, typically 35 mega-pascals to 70 mega-pascals, inside specialized pressure vessels to increase volumetric energy density.
Compressed image – It is a digital image file which has been reduced in size by removing data redundancies using mathematical or signal-processing techniques.
Compressed level – It defines a structural optimization where contiguous groups of bits or multiple tree levels are combined into a single expanded branch level to reduce total tree height and improve search efficiency. Compression levels refer to the grouping of contiguous bits in data structures such as tries, where a level is defined for every ‘K’ bits, resulting in a reduced number of levels and an expanded prefix representation. This process can also be described as prefix expansion, where subtrees of height ‘k’ are compressed into one level.
Compressed natural gas – It is a cleaner-burning fossil fuel alternative to petrol or diesel fuel which is extensively used for generating electricity, providing gas for homes, and powering vehicles such as buses. It is stored in high-pressure fuel tanks and emits fewer pollutants compared to diesel, making it beneficial for reducing air pollution in urban areas.
Compressed pulse – It is the final, narrow, high-amplitude signal output produced after a long, modulated pulse passes through a matched filter during reception.
Compressed sensing – It is a signal processing technique which allows engineers to capture and reconstruct a signal using far fewer samples than the traditional Nyquist-Shannon sampling theorem requires. Instead of sampling a signal at a high rate and compressing it afterward, compressed sensing measures a smaller number of random or pseudorandom projections. It then reconstructs the full signal using optimization algorithms.
Compressibility – Compressibility is the measure of how much a given volume changes instantaneously when placed under pressure. In better words, it is defined as a measure of the relative volume change of a fluid or solid as a response to a pressure change. Hence, if the pressure is increased then the volume decreases considerably. In powder metallurgy, it is the ability of a powder to be formed into a compact having well-defined contours and structural stability at a given temperature and pressure. It is a measure of the plasticity of powder particles. It is also a density ratio determined under definite testing conditions. It is also referred to as compactibility.
Compressibility chart – It is a universal graphical representation used to show how much a real gas deviates from ideal gas behaviour.
Compressibility factor – It is a thermodynamic property used to modify the ideal gas law in order to take into account the real gas behaviour. Normally, deviation from ideal behaviour becomes more significant when the gas is closer to a phase change, with very low temperature or with very high pressure.
Compressibility number – It is a dimensionless group used in gas bearing calculations. It is to be noted that for thrust bearings, the compressibility number relates viscosity, velocity, pressure, and clearance. · For journal bearings, the compressibility number relates to viscosity, rotational speed, pressure, radius, and clearance.
Compressible cake – It is a filter cake which deforms, compacts, or rearranges under an applied pressure difference.
Compressible flow – It is a branch of fluid mechanics which deals with fluid flows where substantial changes in fluid density occur because of the variations in pressure and temperature.
Compressible fluid – It is a fluid whose density varies considerably with changes in pressure, contrasting with incompressible fluids which maintain a constant density regardless of pressure. In certain conditions, such as low-pressure changes, a compressible fluid can behave like an incompressible fluid.
Compressible fluid flow – It is the flow of gases where density variations are substantial, particularly in applications such as gas and steam turbines, reciprocating engines, combustion systems, and high-speed flight. This type of flow is characterized by its treatment of pressure and temperature changes because of the compressibility effects.
Compressible gas – It is a fluid whose density (d) changes considerably in response to variations in pressure (P) and temperature (T), typically analyzed when flow speeds approach or exceed the speed of sound.
Compressible Navier-Stokes equations – These are a set of non-linear partial differential equations which describe the motion of viscous, heat-conducting fluids where the density (d) changes considerably because of the pressure or temperature variations. Unlike incompressible flow (where density is assumed constant), compressible flow needs tracking energy and thermodynamic states, making it necessary for high-speed aerodynamics, shock waves, and combustion.
Compression – It is the application of balanced inward (pushing) forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.
Compressional force – It is a push or squeeze that presses inward on an object or material, making it shorter, smaller, or more compact. Compressional force pushes inward from opposite sides or points. It forces atoms and molecules closer together. This can temporarily change an object’s shape or permanently crush it, depending on the material’s strength.
Compression algorithm – It is a computational procedure designed to reduce the physical size of data for the purpose of optimizing storage efficiency or minimizing transmission bandwidth. This reduction is achieved by executing specialized mathematical formulas through an encoder-decoder (codec) architecture. The encoder identifies and eliminates unnecessary patterns or irrelevancies within the source code, while the decoder reverses the process to reassemble or approximate the original file.
Compressional wave – It is a mechanical wave in which the particles of the medium oscillate parallel to the direction which the wave energy propagates, creating alternating zones of high-pressure compression and low-pressure rarefaction.
Compression asymmetry – It is a mechanical phenomenon where a material shows different yield strengths, stiffnesses, or failure behaviours when pulled (tensile load) against when pushed (compressive load).
Compression axial loading – It is a force applied directly along the longitudinal or central axis of a structural member which pushes the ends toward each other.
Compression axis – It is the directional line or principal axis along which a compressive (pushing or squeezing) force acts, causing a structural member or material to shorten or experience inward stress.
Compression bar – It is a component of a Kolsky bar apparatus which transmits compressive stress pulses generated by a striker impact, facilitating the study of dynamic material behaviour under high strain rates. It typically includes an incident bar and a transmission bar, which are aligned along a common axis with minimized friction for one-dimensional wave propagation.
Compression bending – It is a mechanical state or forming process where a structural element or material curves under loads which squeeze or press one side inward while stretching the opposite side.
Compression capability – It refers to the ability of a technology, such as compressive sensing, to reduce the quantity of data required to represent an image or signal while maintaining high fidelity in its reconstruction. This capability allows for substantial reductions in data size and transmission demands.
Compression-compression fatigue – It is a progressive structural degradation and failure of a material or component caused by the repeated application and removal (or fluctuation) of compressive (squeezing) loads.
Compression corner – It refers to a geometric feature where a surface deflects into an oncoming high-speed fluid stream, creating a sudden flow turn which generates oblique compression waves which merge into a shock wave.
Compression creep – It is the gradual, time-dependent permanent deformation of a material under a sustained compressive load or stress which is below its yield strength.
Compression curve – It is a graphical plot which shows how a material or soil deforms, changes volume, or resists stress when an increasing compressive (squeezing) load is applied.
Compression cycle heat pump – It is a mechanical thermal system which moves heat from a low-temperature source (such as outside air, ground, or water) to a high-temperature sink (such as an indoor space or domestic water supply) by supplying electrical work to a closed refrigerant circuit. Operating on a reversed Rankine thermodynamic cycle, it forces thermal energy to flow against the natural temperature gradient.
Compression efficiency – It is the ratio of the theoretical (ideal) work needed for gas compression to the actual work input consumed by the compressor. ‘Compression efficiency = (theoretical ideal work or power) / (actual work or power delivered)’.
Compression end – It is a connection point on a valve, pipe, or fitting which uses mechanical force, rather than solder, glue, or permanent threading, to clamp a ring or ferrule tightly around a tube. It is also the terminal point or boundary of a mechanical compression process or structural component under compressive load.
Compression face – It refers to the surface or edge of a structural element (such as a beam, slab, or plate) which is subjected to compressive (squeezing) stresses under a bending moment or load.
Compression factor (Z) – It is a dimensionless value which measures how much a real gas deviates from ideal gas behaviour. It is the ratio of the actual molar volume of a real gas (Vm) to the molar volume of an ideal gas calculated at the same temperature and pressure: ‘Z = PV/nRT = Vm, actual / Vm, ideal’, where ‘P’ is the absolute pressure, ‘V’ is the volume of the gas, ‘n’ is the number of moles, ‘R’ is the universal gas constant, and ‘T’ is the absolute temperature (in Kelvin).
Compression flange – It is the widened portion of a structural beam, girder, or member which is subjected to compressive stress (squeezing or shortening forces) caused by bending or loading.
Compression flow – It is the process of settling and packing a slurry inside a column by applying a controlled flow of liquid from the top to the bottom, using a two-step method which involves initially settling the resin at a lower fluid velocity followed by compressing the bed with a higher fluid velocity. This technique is important for achieving the appropriate bed compression in chromatography systems.
Compression forming – It is also normally known as compression moulding. It is a manufacturing process where a pre-heated raw material, called a ‘charge’, is placed into an open, heated mould cavity and squeezed into a desired shape using compressive force.
Compression ignition – It is also called homogeneous charge compression ignition (HCCI). It refers to a combustion mode in which a homogeneous mixture of air and fuel is compressed until auto-ignition occurs, allowing for faster combustion compared to traditional spark ignition or compression ignition methods. Homogeneous charge compression ignition combustion is characterized by its ability to improve thermal efficiency while maintaining low emissions.
Compression-ignition dual-fuel engine – It is an internal combustion engine which burns two different fuels simultaneously, typically a main gaseous or alternative fuel (such as natural gas, hydrogen, liquefied petroleum gas, or biogas) mixed with air, and a small quantity of a high-reactivity liquid pilot fuel (such as diesel or biodiesel) to trigger ignition.
Compression index – It is the absolute value of the slope of the linear (virgin) portion of the void ratio against logarithm of effective stress curve got from a laboratory consolidation (oedometer) test. In civil engineering, it measures the magnitude of main consolidation settlement in normally consolidated fine-grained soils (such as soft clays and organic soils) when subjected to an increase in effective stress beyond their pre-consolidation pressure.
Compression level – It refers to a selectable setting that controls the balance between processing speed and reduction efficiency (file size or data quality). Compression levels refer to the grouping of contiguous bits in data structures such as tries, where a level is defined for every ‘K’ bits, resulting in a reduced number of levels and an expanded prefix representation. This process can also be described as prefix expansion, where subtrees of height ‘k’ are compressed into one level.
Compression load – It is a physical force which pushes inward or presses on a material, structure, or component, causing it to shorten, decrease in volume, or experience negative strain.
Compression management – It is the practice of analyzing, controlling, and mitigating the effects of inward-pushing forces (compressive stress) which act to decrease the volume, length, or cross-sectional dimensions of a material or component. It is also the practice of shortening the planned duration of a construction project schedule to meet a fixed end date, keeping the original scope intact.
Compression members – These are structural elements used in building structures, which can function as columns, chords, or webs, and their maximum strength is influenced by member length and end support conditions. They are classified into short, intermediate, and long members, each showing distinct behaviour under load, with concerns such as local buckling and overall buckling varying by member type.
Compression method – It is a technique used to reduce the physical size, data volume, or spatial dimensions of a substance, file, or signal while maintaining its core utility or structural integrity.
Compression module – It is a specific component, software package, or hardware unit designed to reduce the size of data, files, audio, or system payloads.
Compression modulus – The compression modulus measures the stiffness of the material or the ability of the material to withstand changes in length when subjected to compressive loads. The higher the compression modulus, the stiffer the material.
Compression moulding – It is a technique of thermoset moulding in which the plastic moulding compound (normally preheated) is placed in the heated open mould cavity, the mould is closed under pressure (normally in a hydraulic press), causing the material to flow and completely fill the cavity, and then pressure is held until the material has cured.
Compression network – It refers to an auto associative or feed forward neural architecture designed to map high-dimensional input data onto a smaller intermediate ‘bottleneck’ representation to reduce noise, eliminate gross sensor errors, or compress signal volume.
Compression package – It is a complete, skid-mounted or modular assembly of machinery designed to compress gases (such as natural gas, hydrocarbon process gas, or air) to meet specific flow, pressure, and duty requirements.
Compression parallel – It refers to the use of compression algorithms which are designed to operate efficiently in parallel computing environments, enabling the simultaneous compression and decompression of data across multiple processing units. These algorithms typically involve breaking data into chunks which can be processed independently, although challenges arise because of the data-dependent nature of traditional compression methods.
Compression platform – It is a specialized industrial facility or platform which receives associated or produced natural gas from production wells or neighbouring facilities, increases its pressure through mechanical compressors, and routes it into major transmission pipelines, reinjection systems, or gas-lift networks.
Compression pressure – It refers to the force per unit area generated when a material, fluid, or gas is squeezed or reduced in volume by applied forces.
Compression process – It is a method in which a powder or mixture of powders is compressed between metallic parts to produce products, involving different stages including particle rearrangement, elastic and plastic deformation, and bulk compression under applied pressure.
Compression ratio – It is the volume of the full flight of the screw at the feed opening divided by the volume of the last full flight before discharge, with typical ranges from 1:1 to 5:1. Compression ratio in an internal combustion engine is the measure of how much the air-fuel mixture is squeezed inside the cylinder, calculated as the ratio of the maximum cylinder volume (at the bottom of the piston stroke) to the minimum volume (at the top of the stroke). In powder metallurgy, it is the ratio of the volume of the loose powder to the volume of the compact made from it.
Compression refrigeration system – It is a technology which utilizes a refrigerant circulating in a closed system to absorb and release heat, effectively cooling a designated space while rejecting excess heat through its components.
Compression reinforcement – It refers to steel bars (reinforcement bar) or mesh placed in the compression zone of a concrete member (such as a beam or column) to help resist compressive forces.
Compression resilience – It is a material’s ability to absorb energy under a compressive load and return to its original shape or thickness after the load is removed, without permanent damage. For porous, foam, or elastomeric materials, compression resilience (CR) is frequently measured as the ratio of work done during the recovery process to the work done during compression, expressed as a percentage.
Compression resin transfer moulding – It is a manufacturing process for composite materials which improves the rapid production of high-quality composite parts by reducing resistance to resin flow in high fibre content reinforcing materials. This process needs larger mould-closing forces to achieve reduced production cycle times.
Compression scheme – It is a systematic method, algorithm, or hardware-software framework used to reduce the size of data, signals, or test patterns to save storage space and network bandwidth.
Compression set – It is the deformation in a material which is remaining after it has been subjected to and released from a compressive force. In seals, it is the difference between the thickness of a gasket of static seal before the seal is compressed and after it is released from compression. Compression set is normally expressed as a percentage of the total compression.
Compression space – It refers to the enclosed volume inside a compressor, cylinder, or fluid chamber where a gas or mixture is compressed by a moving member (such as a piston, screw, or vane).
Compression springs – These springs are designed to operate with a compression load and hence the spring becomes shorter as the load is applied to it.
Compression stage – It is a single, discrete step in a fluid-handling or gas-handling system where a gas or air is compressed from one pressure level to a higher-pressure level.
Compression standards – These are the specifications which outline the bit-stream format and decoding process for digital media, ensuring interoperability across different devices and networks. These standards facilitate the production of compliant encoders and decoders, which can handle a standardized bit-stream.
Compression steel – It refers to a structural steel element which is subjected to axial (or combined axial and bending) compressive loads which attempt to shorten, crush, or buckle the member.
Compression strut – It is a structural member designed Dextra to resist longitudinal (axial) compression forces, preventing structural elements from moving closer together or collapsing.
Compression system – It is an integrated arrangement of equipment, controls, and mechanical components designed to draw in a gas or vapour, reduce its volume, and discharge it at a higher pressure.
Compression test – It is a method for assessing the ability of a material to withstand compressive loads. It applies a controlled, uniaxial crushing load along a sample’s longitudinal axis to measure mechanical behaviour and resistance to permanent deformation or fracture.
Compression test conditions – These include type of loading (uniaxial compressive force applied inward through parallel machine platens rather than tensile grips) , sample geometry (cylindrical slugs or rectangular prisms designed with low height-to-diameter ratios to prevent premature sample buckling), alignment and friction (platens is to remain flat, parallel, and lubricated to minimize barreling effects caused by surface friction, start / end criteria (tests begin at a threshold pre-load (force criterion) and end at a defined height reduction or deformation limit which is displacement criterion), and environmental controls (ambient or high temperatures coupled with specific strain rates to simulate bulk metal-forming operations like forging or rolling.
Compression testing – It is a mechanical testing method where a material sample is placed between two platens on a universal testing machine (UTM) and squeezed with a controlled, inward uniaxial force until it deforms or fractures.
Compression train – It is a system designed to compress captured carbon di-oxide (CO2) for efficient pipeline transport, incorporating components such as centrifugal compressors, after-coolers, and scrubbers, while accounting for specific mechanical limitations and operating pressures. Compression train is an integrated, sequential line of machinery and auxiliary systems working together to raise the pressure of a gas or vapour.
Compression volume – It typically refers to the clearance volume in a reciprocating engine or cylinder—the remaining volume inside the cylinder when the piston reaches top dead center (TDC).
Compression wave – It is a type of longitudinal wave where the oscillation occurs along the direction of propagation, involving the compression and rarefaction of particles in the medium through which it travels.
Compression zone – It is the specific region of a structural member (like a beam, slab, or column) or a mechanical process (like sedimentation in wastewater treatment) which experiences squeezing, shortening, or compacting forces.
Compressive – It is pertaining to forces on a body or part of a body which tend to crush, or compress, the body.
Compressive behaviour – It refers to how a material, component, or structure deforms, stiffens, or fails when subjected to inward-pushing (axial) loads which try to shorten or crush it.
Compressive burr – It is the burr produced in blanking or piercing operations in which the slug separates from the stock in a compressive stress field. Burrs produced in this manner initially begin as tensile burrs and are typically identified as tensile-plus-compressive burrs.
Compressive cold working – It is a metal-shaping process done at room temperature where a material is squeezed or compressed to change its shape and make it stronger.
Compressive deformation – It is the change in the shape, thickness, or volume of a material when it is squeezed or pushed together by opposing external loads.
Compressive force – It is a push or load which squeezes, compacts, or presses inward on an object, causing its length or volume to decrease. It is a mechanical force directed toward an object which tries to crush, shorten, or squeeze it. It is the exact opposite of a tensile (pulling) force.
Compressive hoop stress – It is a directional, internal mechanical stress which acts circumferentially around the perimeter of a rotationally symmetric object (such as a cylinder, tube, or ring) and forces the material’s particles inward toward each other. Unlike standard tensile hoop stress, which pushes outward to burst a cylinder under internal pressure, compressive hoop stress compresses the circumference to reduce its diameter.
Compression load – It refers to the force applied to compress a material, causing it to shorten and deform under increasing pressure, which is critical for assessing the mechanical properties of materials used in different structures.
Compressive loading – It is a mechanical force applied to a material or structure which pushes inward or squeezes it, reducing its volume or length while causing elastic or plastic deformation.
Compressive membrane action – It is a structural behaviour in reinforced concrete slabs (and one-way ‘arching action’ in linear members) where lateral edge restraints prevent in-plane expansion, inducing horizontal compressive forces which considerably increase load-carrying capacity.
Compressive modulus – It is the ratio of compressive stress to compressive strain below the proportional limit. Theoretically it is equal to Young’s modulus determined from tensile experiments.
Compressive region – It is an area within a structure, component, or material cross-section where compressive stresses (pushing or squeezing forces) are present, causing fibres or volume to shorten and needing specific analysis distinct from tensile (pulling) regions.
Compressive residual stresses – These are internal, self-balancing forces locked inside a material which push inward on its atomic structure without any external loads applied.
Compressive residual stress zone – It is the sub-surface region of a metal component where permanent internal elastic stresses act in a negative (compressive) direction without any external load. This localized zone is intentionally engineered to neutralize tensile stresses which cause cracking, fatigue failure, and corrosion.
Compressive sampling – It is a signal processing and data acquisition technique which allows a person to capture and reconstruct a signal using far fewer measurements than the traditional Nyquist–Shannon sampling theorem needs. Instead of sampling a signal at twice its highest frequency (the Nyquist rate), compressive sampling performs data acquisition and compression at the same time.
Compressive sensing – It is a signal processing technique which acquires and reconstructs signals from far fewer samples than traditionally needed by the Nyquist–Shannon sampling theorem. Instead of sampling a signal at a high rate and compressing it later, it captures the signal directly in a compressed format.
Compressive shrinkage stress – It is frequently broken down into its two components namely shrinkage stress and compressive residual stress. It refers to the internal inward-pushing forces generated within a metal component because of the volumetric contraction during thermal processing, phase transformation, or mechanical cold working.
Compressive strain – It is the measure of how much an object shortens when a pushing or squeezing force is applied to it. It is the ratio of the decrease in length to the original length of a body subjected to compressive stress.
Compressive strain capacity – It refers to the maximum quantity of compressive (squeezing) deformation or strain a material, structural element (such as a concrete column), or pipeline can withstand before failure, local buckling, or structural collapse occurs.
Compressive strain distribution – It refers to the spatial variation of dimensional shortening across a metal work-piece when it is subjected to squeezing forces. While basic compressive strain (ec) is the uniform, dimensionless ratio of reduction in length to original length (dL/L0), strain distribution tracks how this deformation varies from the surface to the core of a bulk material during manufacturing processes like rolling, forging, or extrusion.
Compressive strength – It is the maximum compressive stress which a material is capable of developing, based on original area of cross section. If a material fails in compression by a shattering fracture, the compressive strength has a very definite value. If a material does not fail in compression by a shattering fracture, the value got for compressive strength is an arbitrary value depending on the degree of distortion which is regarded as indicating complete failure of the material.
Compressive strength result – It is the maximum load or stress a material can withstand under crushing or squeezing forces before it fractures, cracks, or deforms permanently. It measures a material’s resistance to volume-decreasing or compressive forces, opposite to tensile strength which measures resistance to pulling apart.
Compressive stress – It is a stress which causes an elastic body to deform (shorten) in the direction of the applied load. It is the internal resistance force per unit area which pushes a material together.
Compressive stress relief – It is a mechanical stress-relieving process where a controlled compressive force is applied to plastically deform a metal part slightly, reducing undesirable internal residual stresses.
Compressive stress state – It refers to a condition where the material experiences a net inward force, resulting in a decrease in dimensions, as exemplified by the compressive stress observed in tubes under high external pressure.
Compressive test – It is a mechanical test which applies a crushing, squeezing, or pushing load (uniaxial compressive force) to a material sample to measure its behaviour, stiffness, and resistance to deformation or failure.
Compressive testing – It is a mechanical test which applies a crushing, axial compressive force to a material sample to measure its strength, deformation behaviour, and stiffness under pressure.
Compressive thermal stress – It is the internal squeezing force per unit area which develops inside a metal component when a rise in temperature causes it to expand, but physical constraints or uneven cooling prevent that expansion.
Compressive twin – It is also called a contraction twin. It is a type of deformation twin where a crystal lattice reorients so that its c-axis shortens or contracts during plastic deformation. It is a planar crystal defect where part of the atomic lattice shifts into a mirror-symmetric orientation which accommodates compressive strain by shrinking the crystal structure along a specific axis.
Compressive yield strength – It is the specific stress level where a material stops bouncing back and starts to change shape for good when squeezed. If people push on a material past this point, it stays shorter even when people take the push away.
Compressometer – It is an Instrument for measuring change in length over a given gauge length caused by application or removal of a force. It is normally used in compression testing of metal samples.
Compressor – It is a device which converts mechanical power or force to pneumatic fluid power.
Compressor applications – These applications refer to the different uses of compressors in the upstream, midstream, and downstream sectors of gas and oil engineering, including gas gathering, export compression, gas lift, and natural gas processing, among others. These applications utilize different types of compressors, such as centrifugal and reciprocating, to facilitate the movement, compression, and processing of gases.
Compressor blades – These are aerofoil-shaped components in a gas turbine or compressor which add energy to a working fluid, such as air, by increasing its pressure, velocity, and density.
Compressor capacity – It is the volume or mass flow rate of gas (such as air) which a compressor can deliver per unit of time at a specified discharge pressure and inlet condition.
Compressor case – It is the outer shell which houses the internal components of a centrifugal compressor, typically split along a horizontal centre-line for assembly, designed to operate under specific pressure conditions, with materials of construction varying based on metallurgical needs and gas pressure.
Compressor discharge – It refers to the region, port, or process where a gas or refrigerant exits a compressor at a higher pressure and temperature after the mechanical compression process.
Compressor discharge air – It is the compressed, high-pressure, and high-temperature gas or air which exits through the outlet flange or valve of a compressor after the mechanical compression process is complete.
Compressor efficiency – It is the ratio of the ideal (theoretical) work needed to compress a gas to the actual work input consumed by the compressor. Since real-world compression involves friction, heat exchange, and turbulence, actual work is always higher than ideal work, making efficiency less than 100 % (typically 50 % to 95 % depending on the design).
Compressor inlet – It is the opening, duct, or valve assembly where a working fluid (such as air, gas, or refrigerant) enters the compression mechanism. It consists of the physical port, flange, or manifold which routes the low-pressure fluid from the external environment or preceding system into the first stage of the compressor.
Compressor inlet pressure – It is the total or static pressure of a gas or air at the entry flange, intake port, or suction filter of a compressor. It represents the baseline or starting pressure of the working fluid right as it enters the compression mechanism. It can be measured as static pressure or total (stagnation) pressure depending on the system design.
Compressor inlet temperature – It is the total temperature of the gas or air measured directly at the intake connection or suction flange of a compressor. It represents the thermodynamic state of the working fluid before compression begins, frequently serving as the baseline entry point in cycles like the Brayton cycle.
Compressor isentropic efficiency – It is a performance metric which quantifies the level of irreversibility in a compressor, calculated as the ratio of isentropic work to actual work.
Compressor lube oil – It is a specialized mineral, synthetic, or semi-synthetic fluid engineered to lubricate, seal, cool, and protect moving mechanical parts inside gas and air compressors, such as rotary screw, reciprocating, vane, and centrifugal units.
Compressor oil – It is a lubricant used in air compressors to facilitate sealing, lubrication, and cooling during the compression process, which can degrade and oxidize because of the heat, leading to the formation of varnish and acidic substances.
Compressor performance – It is the measure of how effectively a compressor converts input shaft power or energy into the desired pressure and flow rate of a gas. It is evaluated by analyzing thermodynamic efficiency, pressure ratios, flow capacity, and operational maps.
Compressor power consumption – It is the total electrical or mechanical power (measured in kilowatts, or watts) needed to operate a compressor and compress a gas from a lower inlet pressure to a higher discharge pressure.
Compressor pressure ratio (r) – It is the ratio of the absolute discharge pressure (Pdischarge) to the absolute inlet (suction) pressure of a compressor (Pinlet). Pressure ratio(r) = Pdischarge / Pinlet.
Compressor refrigeration system – It is normally called a vapour compression refrigeration system or VCRS). It is a thermodynamic cooling cycle which uses mechanical energy to transfer heat from a low-temperature space to a high-temperature ambient environment.
Compressor reliability – It is the ability of a compressor to perform its intended function consistently without failure under specified operating conditions for a stated time interval, frequently exceeding 99.7 % availability when managed with best practices.
Compressor rotor – It is a rotating mechanical component inside a compressor which transfers kinetic or mechanical energy to a gas or air, increasing its pressure and density.
Compressor section – It refers to a group of compression stages or a dedicated portion of a mechanical system (such as a gas turbine, jet engine, or multi-stage centrifugal compressor) bounded by casing nozzles, anti-surge limits, or distinct pressure / temperature zones.
Compressor stage – It is one impeller along with the stationary inlet and discharge passages, including the inlet guide vanes and the diffuser, which collectively produce a specific quantity of head and have a defined stage efficiency at a given flow and impeller speed.
Compressor station – It is a large industrial facility which increases the pressure of natural gas in a transmission or gathering pipeline to keep the gas moving smoothly over long distances.
Compressor suction – It refers to the inlet side of a compressor and the physical state, mainly pressure, temperature, and mass flow rate, of the gas or air entering it.
Compressor type – It refers to the classification of gas compressors based on their operational principles, which are mainly divided into positive displacement compressors and dynamic compressors. Positive displacement compressors reduce the volume of gas in a trapped space, while dynamic compressors continuously increase the gas’s momentum without relying on a trapped volume.
Compressor work – It is the mechanical shaft work (energy) supplied by an external driver, such as an electric motor or engine, to increase the pressure and density of a gas by reducing its volume.
Compromise – It is a design trade-off where an engineer accepts less of one quality or feature to gain more of another conflicting requirement.
Compton effect – It is the decrease in energy and corresponding increase in wave-length of an X-ray or gamma-ray photon when it collides with a charged particle, usually an electron.
Compton scattering – It is the elastic scattering of photons by electrons. Compton scattering is the quantum theory of scattering of a high-frequency photon through an interaction with a charged particle, normally an electron. Specifically, when the photon interacts with a loosely bound electron, it releases the electron from an outer valence shell of an atom or molecule.
Computable measures – These measures refer to quantitative analyses derived from tracked object trajectories, including metrics that characterize motility, diffusivity, velocity, and morphology based on sequences of coordinate positions over time. These measures enable the assessment of movement patterns and behaviours, such as total trajectory length and mean squared displacement.
Computational aerodynamics – It uses computational methods to solve fluid dynamics problems, particularly through algorithmic approaches which facilitate substantial advances in aerodynamic design and analysis.
Computational analysis – It is the use of mathematical models, computer algorithms, and high-performance computing to simulate, test, and analyze the behaviour of physical systems before building a real-world prototype.
Computational basis – It refers to a selected set of reference building blocks, functions, or vectors used to construct matrices, discretize continuous physical models, or represent states in a computer system.
Computational complexity – It is the quantity of computing resources, mainly time and memory space, an algorithm or system needs to process an input of a given size.
Computational constraints – These are the hard boundaries and resource limitations placed on a system’s data processing, algorithm execution, and digital architecture. They dictate what an algorithm or software can achieve within real-world physical and hardware limits.
Computational domain – It is the defined two-dimensional or three-dimensional geometric space where numerical simulations and mathematical equations (such as the Navier-Stokes equations for fluid flow) are solved.
Computational expense – It is the total quantity of computing resources, such as execution time, memory (random-access memory, RAM), processor (central processing unit / graphics processing unit, CPU / GPU) power, and input / output operations, needed to run a simulation, model, or algorithm.
Computational fluid dynamics – It is a branch of fluid mechanics which uses numerical analysis and data structures to analyze and solve problems that involve fluid flows. The basis of almost all the problems of computational fluid dynamics the Navier Stokes equations. Finite element method is the most used. The domain is divided into several little volumes in which the conservation equations are discretized and solved.
Computational fluid dynamics methods – These methods refer to computational fluid dynamics techniques used to analyze fluid flow and its interactions with surfaces, providing timely results for product development and engineering applications. These methods incorporate relevant physics, ensure numerical accuracy, and are validated for practical use in engineering contexts.
Computational fluid dynamics modelling – It is a method which utilizes numerical methods and algorithms to solve problems involving fluid flows, based on the principles of mass, momentum, and energy conservation. It enables the simulation of multiphase flow and interactions of liquids and gases, providing a realistic representation of fluid behaviour in different applications.
Computational grid – It is a hardware and software infrastructure which links geographically distributed, heterogeneous computers and resources across different administrative domains to act as a single, virtual super-computer. A computational grid can also refer to a mesh used to discretize a physical domain for methods like finite volume analysis.
Computational homogenization – It is a multi-scale model[ing technique used to determine the effective macroscopic mechanical or physical behaviour of heterogeneous materials (such as composites, porous media, or architectured structures) by numerically analyzing their fine-scale microstructure.
Computational mechanics – It is a field which has evolved from simple methods and models to advanced algorithmic developments and first-principles based multi-physics solvers, aimed at solving scientific and technological problems through virtual experimentation and integration with machine learning and artificial intelligence technologies.
Computational micro-mechanics – It is an engineering and applied mechanics discipline which predicts the macroscopic (effective) mechanical behaviour of heterogeneous materials by numerically solving boundary value problems on a representative unit of their micro-structure.
Computational micro-structure characterization – It is the quantitative statistical representation of a material’s internal morphology and geometric features using digital imaging and computational algorithms.
Computational micro-structure reconstruction – It is the algorithmic process of generating synthetic 2D or 3D digital models of a metal’s internal structure which are statistically identical to real experimental samples. Rather than physically cutting and slicing a metal sample, which is costly, time-consuming, and destructive, metallurgists use computational methods to analyze a small experimental image (like a scanning electron micrograph) and digitally expand or synthesize a larger, 3D volume which matches its structural features. This digital twin is then used to test how the metal performs under stress, heat, or corrosion.
Computational modelling – It is the process of using computers to simulate and study complex systems or phenomena. It involves creating mathematical and logical representations of these systems, frequently using computer code, to analyze, predict, or optimize their behaviour. Essentially, it is about using computers to create virtual versions of real-world problems and systems to better understand them.
Computational nodes – These nodes refer to specific points within a computational grid where solution variables are represented, which can be located at the vertices, centroid, or edges of grid cells. These nodes facilitate the construction of discrete solutions for various element types, impacting the accuracy and complexity of the computational model.
Computational power – It is the capacity of a computer system or hardware component to process large quantities of data and execute complex calculations efficiently.
Computational reconstruction – It is the process of using computer algorithms and mathematical models to recreate a detailed three-dimensional object, image, or dataset from limited, indirect, or two-dimensional measurements.
Computational rheology – It is the sub-field which uses numerical methods and computer simulations to analyze and predict the flow and deformation behaviour of complex fluids (such as polymers, melts, suspensions, and viscoelastic materials). It bridges continuum mechanics and material science by solving non-linear mathematical equations which describe how complex materials respond to stress, strain, and time.
Computational solid mechanics – It is a sub-field of applied mechanics which uses numerical methods and computer algorithms to simulate and analyze the behaviour of solid materials and structures under different forces, loads, and environmental conditions.
Computational solution – It is a mathematical or algorithmic method used to solve, simulate, or approximate a complex physical or system model with high numerical accuracy using computers.
Computational space – It refers to the discrete, virtual, or mathematical domain created within a computer to represent, discretize, and simulate physical phenomena or geometric systems.
Computational step – It is a single, discrete operation or calculation within a larger algorithmic or numerical simulation which transforms physical laws and mathematical models into computer-executable logic.
Computational structural engineering – It is a multi-disciplinary field which combines structural mechanics, applied mathematics, and computer science to model, simulate, analyze, and optimize the behavior of physical structures using digital tools.
Computational structure dynamics – It refers to the numerical simulation of the elastic motion of structures by solving the structure equation of motion using methods like the finite element method. It is integrated with computational fluid dynamics in fluid-structure interaction problems to analyze the dynamic response under different flow conditions.
Computational thermodynamics – It is the use of computers and mathematical models to simulate thermodynamic properties, phase stability, and chemical reactions in materials.
Computational work – It refers to a collection of digital processes, data-gathering tasks, analyses, and mathematical modelling used to predict, simulate, and optimize physical or system behaviour.
Computed radiography (CR) system – It is a digital X-ray imaging method which replaces traditional film with reusable phosphor storage plates. It acts as a bridge between classic film-based radiography and fully digital systems.
Computed tomography – It is a non-destructive imaging method which uses rotating X-ray beams and computer algorithms to reconstruct detailed cross-sectional and 3D internal models of an object.
Computed tomography (CT) imaging – It is a non-destructive testing and imaging modality which uses penetrating X-radiation and rotating sources / detectors to measure radiation attenuation and scattering, mathematically reconstructing detailed 2D and 3D cross-sectional models of an object’s internal morphology.
Computer – It is a machine which can be programmed to automatically carry out sequences of arithmetic or logical operations. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks.
Computer aided analysis – It refers to the use of software tools to assist in the analysis of data, emphasizing the importance of accurate input data and the qualifications of the analyst to avoid misleading results.
Computer aided design – Computer-aided design (CAD) is a way to digitally create 2-D drawings and 3-D models of real-world products before they are manufactured. With 3-D computer aided design, a person can share, review, simulate, and modify designs easily, opening doors to innovative and differentiated products.
Computer-aided design / computer-aided manufacture – It refers to the integration of computer-aided design (CAD) with computer-aided manufacturing (CAM), allowing for the rapid generation of detailed models and automated production processes. This combination improves design capabilities and facilitates efficient manufacturing by using software to create and manipulate geometric data for different applications.
Computer-aided design (CAD) model – It is an exact digital representation of a physical component or system, defined by precise geometry, dimensions, material properties, and spatial relationships. It describes the digital 3D representation of metal parts, assemblies, or casting / welding tooling embedded with specific material properties, microstructural attributes, and manufacturing constraints.
Computer-aided design (CAD) software – It is a digital tool which engineers, architects, and drafters use to create, modify, analyze, and document 2D drawings and 3D models of physical components and structures, replacing traditional manual drafting with T-squares and protractors.
Computer-aided design (CAD) system – It is an integrated suite of computer software and hardware tools which engineers, architects, and designers use to create, modify, analyze, and document 2D and 3D digital models of physical objects.
Computer-aided engineering – Computer-aided engineering (CAE) is the use of computer software across industries to simulate product performance to improve designs or assist in the resolution of engineering problems. This includes simulation, validation and optimization of products, processes and manufacturing tools.
Computer-aided engineering (CAE) systems – These are software tools used to digitally simulate, validate, and optimize product designs and manufacturing processes before building physical prototypes.
Computer-aided engineering (CAE) HEARTS – HEARTS stands for HEAt tReaTment Simulation system. It a specialized software framework designed to simulate metallic structures, transient temperatures, and thermal-stress / strain behaviours during metal processing.
Computer-aided industrial design – It is a subset of computer-aided design (CAD) software focused on shaping the aesthetics, ergonomics, and look-and-feel of a product during development. Unlike traditional computer-aided design, which prioritizes precise technical and mechanical engineering constraints, computer-aided industrial design (CAID) leans into the artistic and conceptual phase of design. It gives creators more freedom to build organic forms and smooth freeform shapes.
Computer-aided instruction – It refers to the application of computer systems, software simulations, and interactive courseware to deliver technical training, guide learners through abstract design or computational exercises, and practice complex engineering workflows at their own pace.
Computer aided manufacturing – Computer-aided manufacturing (CAM) is also known as computer-aided modeling or computer-aided machining. It is the use of software to control machine tools in the manufacturing of the work-pieces, and to automate the manufacturing process. It is the software which tells a machine how to make a product by generating toolpaths.
Computer-aided materials selection system – It is a computerized database of materials properties operated on by an appropriate knowledge base of decision rules through an expert system to select the most appropriate materials for an application.
Computer-aided molecular design – It is defined as a computational methodology which enables the design and optimization of molecules by screening for superior performance while calculating different chemical and physical properties based on the contributions of simple chemical groups. This approach allows for the prediction of known molecules’ behaviour or the synthesis of novel molecules, leading to substantial performance improvements over traditional methods.
Computer-aided process planning – It is the use of computer software and digital databases to translate product design specifications (from computer-aided design) into detailed, step-by-step manufacturing instructions and operational routings (for computer-aided manufacturing and the shop floor).
Computer-aided process planning (CAPP) programme – It is a computer programme which extracts the relevant geometric features from a computer aided design drawing and produces a process sequence or set of tool paths (for machining) which is optimal with respect to some criterion such as minimum processing time.
Computer-aided roll pass design – It is the use of computer software and numerical algorithms to plan and optimize the sequence of grooves cut into rolling mill rolls.
Computer-aided software engineering – It is the application of computer-based software tools and methods to automate, support, and standardize activities across the entire software development lifecycle. Computer-aided software engineering (CASE) acts as an automated assistant for software engineers, project managers, and testers. It helps build high-quality, defect-free programmes by making processes disciplined and organized.
Computer-aided software testing – It refers to the use of automated software tools and programmes to execute tests, evaluate results, and manage the software quality assurance process.
Computer-aided tool – It refers to using digital software and computational frameworks to design, specify, model, and manage the functional and physical definitions of tools, machinery, and manufacturing components.
Computer automated rapid prototyping – It is a term used to describe the automated fabrication of physical models, parts, or assemblies directly from 3D computer-aided design (CAD) data. It acts as the technical bridge between digital modelling software and advanced manufacturing hardware, removing manual toolpath planning to speed up the product design validation cycle. While historically referred to simply as rapid prototyping (RP), the addition of ‘computer automated’ emphasizes the seamless software-to-machine loop, frequently controlled through Industry 4.0 cyber-physical systems, where a computer translates a 3D file into cross-sectional layers or toolpaths without needing custom factory tooling.
Computer-automated rapid prototyping – It is a fast method used to build physical scale models or parts directly from three-dimensional digital data using automated manufacturing technologies like 3D printing.
Computer-based technology – It is a multi-disciplinary field which combines electrical engineering and computer science to design, develop, and test computer hardware, software systems, and automated industrial tools.
Computer-based training – It is a method of education which utilizes computers to deliver training materials, making it particularly effective for academic training, simulation, and drill-and-practice exercises. It is preferred by students for its engaging design compared to traditional training methods.
Computer-controlled five-axis robotics system for laser shot peening – It is an automated mechanical motion set-up which systematically manipulates either a high-energy pulsed laser nozzle or a metallic work-piece across five independent geometric axes (typically ‘X’, ‘Y’, ‘Z’ linear axes and two rotational axes). This system precisely targets and delivers shock-waves to complex 3D geometries to induce deep, uniform compressive residual stresses, ultimately improving the material’s fatigue life and resistance to failure.
Computer-controlled hammers – These are frequently referred to as CNC (computer numerical control) forging hammers or programmable power hammers) are automated, industrial metalworking machines which use computer numerical control (CNC) to regulate the velocity, stroke frequency, and impact energy of a reciprocating ram. These machines are mainly utilized in open-die forging and closed-die drop forging to transform raw metal billets into high-strength structural components.
Computer control system – It is an integrated arrangement of digital computers, software, and hardware components used to monitor, regulate, and automate the behaviour of physical machinery, industrial processes, or dynamic systems in real time.
Computer cursor – It is a movable visual indicator on a screen which shows where a user’s next action, click, or typed character is going to occur.
Computer engineering – It is a branch of engineering which integrates electrical engineering, electronics, and computer science to design, build, and test computer hardware and software systems.
Computer-generated imagery – It is a specific-technology or application of computer graphics for creating or improving images in art, printed media, simulators, videos and video games. These images are either static or dynamic. Computer-generated imagery both refers to 2-D computer graphics and (more frequently) 3-D computer graphics with the purpose of designing characters, virtual worlds, or scenes and special effects.
Computer graphics – It is the discipline of using computers to create, store, manipulate, and display visual models of physical objects, systems, and data.
Computer image analysis – It is the automated, computer-based process of extracting quantitative and qualitative information from 2D or 3D digital images (such as size, shape, volume, colour, and texture).
Computer-integrated manufacturing – It is an engineering and production approach which uses networked computer systems, software, and databases to automate, monitor, and coordinate every stage of the manufacturing organization. Instead of treating design, production, and business operations as separate tasks, computer-integrated manufacturing (CIM) links them into a single, continuous information flow. Data created at one step (such as a part design) is instantly available to every other step (such as process planning, tool programming, and inventory management).
Computer interaction – It is the processes and methods by which users engage with computer systems, encompassing the collaboration between individuals, technology, and the design of their interactions to ensure usability and effectiveness.
Computerized maintenance management system – It provides such support. It is also called computer managed maintenance system, or computerized asset management systems (CAMS). It is computer software programmes designed to assist in the planning, management, and administrative control needed for effective maintenance. The output of these programmes can involve writing, planning, and recording work accomplished, collecting a history of work accomplished, recording shipping and receiving transactions, and generating reports.
Computerized numerical control – It is a manufacturing method which uses computers to automatically control machine tools. Instead of a person moving cranks and levers by hand, a pre-programmed digital code tells the machine how fast, how deep, and where to move to cut and shape materials like metal, wood, or plastic.
Computer memory – It refers to the physical semi-conductor circuits, components, and storage locations which temporarily or permanently hold digital data (binary 1s and 0s) for access by a computer’s central processing unit (CPU).
Computer modelling – It is the process of creating a virtual, mathematical representation of a physical system, product, or structure using specialized software to analyze and predict its real-world behaviour.
Computer modelling of micro-structure evolution – Computer modelling of micro-structure evolution is the use of software and mathematical algorithms to simulate how the internal grain structure, phases, and defects of metals change during manufacturing processes like heating, cooling, casting, or rolling.
Computer monitor – It is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
Computer numerical control – It is the automated control of the machine tools by means of a computer. It is used to operate machine tools such as drills, lathes, mills, grinders, and roll turning and roll grinding machines. Computer numerical control machine tools transform a piece of material into a specified shape by following coded programmed instructions and without a manual operator directly controlling the machining operation.
Computer numerical control (CNC) milling – It is an automated, subtractive manufacturing process where pre-programmed computer software and digital codes (like G-code) dictate the movement of rotating cutting tools to remove material from a solid work-piece.
Computer-numerical-controlled (CNC) servo-hydraulic multi-platen powder press – It is an advanced industrial machine used in powder metallurgy and ceramic processing to compact loose powder into complex, high-density solid parts.
Computer numerically controlled – It refers to a type of numerical control system which uses coded instructions to automate the operation of machine tools, allowing for complex geometry generation and improved positional repeatability compared to manual processes.
Computer numerically controlled (CNC) punch press – It is an automated, programmable machine tool used in manufacturing to precisely punch holes, cut shapes, and form features into sheet metal.
Computer numerically controlled (CNC) spin forging – It is also known as shear spinning, flow forming, or spin forming. It is a chipless metalworking process where a rotating metal blank or preform is incrementally deformed over a mandrel by computer-controlled rollers to create hollow, axially symmetric components. Unlike subtractive machining which cuts material away, CNC (computer numerical control) spin forging uses localized hydraulic pressure to force the metal to flow, intentionally reducing wall thickness while realigning the underlying grain structure.
Computer operator – Computer operator is a technical professional who monitors, maintains, and controls computer hardware, mainframes, servers, and peripheral equipment to ensure smooth daily operations. The role bridges the gap between physical machinery / systems and digital data processing.
Computer programme – It is a set of step-by-step instructions which tells a computer hardware system how to perform a specific task or produce a desired result.
Computer programme drawing – It describes the design details, establishes item identification, and provides for control of the software it represents. Three types of drawings are normally used. These are (i) computer programme listing drawing, (ii) computer programme assembly drawing, and (iii) computer programme set drawing. Computer programme listing drawing is prepared to document operational computer programmes / software. It provides design details and establishes item identification for the computer programme. It identifies the master source code, object code, or both, for the computer programme in human readable form. The drawing specifies the media materials, marking requirements, and the applicable specifications. The type of software tools (computer, assembler, and compiler etc.) needed to produce the object code from the source code is also specified. The computer programme assembly drawing contains computer generated load maps of computer programmes with multiple components / sub-programmes. It lists each sub-programme and specifies the media materials, type of equipment needed to produce the computer programme, marking requirements, and applicable specifications. It establishes item identification for the assembly process. The computer programme set drawing groups two or more individual computer programmes into a set for handling convenience. It consists of a parts list which identifies the computer programmes and applicable notes. It establishes item identification for the set.
Computer simulation – It is a digital mathematical model used to imitate, predict, and analyze the behaviour of metallic materials and processes.
Computer simulation study – It is the process of using digital mathematical models and algorithms on a computer to imitate, analyze, and predict the dynamic behaviour of a real-world or hypothetical system.
Computer-supported cooperative work – It is an interdisciplinary field of study focused on how multiple people collaborate toward a shared goal using computer systems, and how technology can be designed to support, mediate, and regulate those group activities. Computer-supported cooperative work (CSCW) bridges social science, human-computer interaction (HCI), and software engineering to build and evaluate groupware, the software and tools which enable team communication, shared workflows, and coordinated actions across time and space.
Computer system – It is an integrated collection of hardware, software, data, and firmware components which work together to accept, process, store, and output information.
Computer technology – It is the use of hardware, software, and networks to store, process, and share information.
Computer tomography imaging – It is an imaging modality which uses penetrating X-radiation to create detailed images of an object’s internal morphology by measuring X-ray scattering and absorption as the radiation rotates around the object.
Computer vision – It is an inter-disciplinary field of artificial intelligence (AI) and computer science which trains machines to acquire, process, analyze, and understand digital images and videos the way humans do.
Computer vision engineering – It is the practical application of computer vision theory. It focuses on designing, building, deploying, and maintaining scalable vision-based systems in real-world environments such as factory automation.
Computer worm – It is a type of malware which can replicate itself and spread to other computers, frequently targeting specific systems such as industrial control systems.
Computing and information technology – It is the discipline which combines engineering principles, computer science, and practical system management to design, build, deploy, and maintain hardware, software, and network infrastructures.
Computing device – It is a functional unit which can perform substantial computations, including numerous arithmetic operations and logic operations without human intervention. A computing device can consist of a standalone unit or several interconnected units. It can also be a device which provides a specific set of functions, such as a phone or a personal organizer, or more general functions such as a laptop or desktop computer.
Computing platform – It is the integrated hardware and software environment used to run simulations, process control systems, and data models for metal extraction, refining, and material design.
Computing power – It is the capability of a computer system to process data, execute instructions, and perform mathematical or logical calculations. It measures how fast and efficiently a system handles complex work-loads.
COMSOL multi-physics – It is a computing platform used to develop models which account for complex physical phenomena, such as diffusion processes and chemical reactions, in engineering applications like analyzing fuel performance and crack propagation in cladding materials.
CONARC process – The basic concept of CONARC process is to carry out decarburization in one furnace shell and electric melting in another furnace. The process starts with the oxygen-blowing stage, which is followed by the electric arcing stage. The whole process operates in sequences inter-changeable in both furnace shells, starting with hot metal charging, then the oxygen lance is put into operation and start of the blowing. At the end of the blowing stage, solid charge materials like scrap and / or direct reduced iron are charged into the furnace shell, the electrodes are swung in the operating position and arcing starts. At the end of arcing, deslagging takes place. Finally, the liquid steel is tapped into the ladle.
Concatenation method – It is a classical technique used for the analysis of axially varying wave-guides, allowing for the examination of light coupling phenomena and propagation characteristics by approximating smooth coupling regions with a staircase approach.
Concave – It is a surface or a line which is curved inward. It is having an outline or surface which curves inwards like the interior of a circle or sphere.
Concave curve – The concave radius of a conveyor is to be sufficiently large to avoid belt lifting from the conveyor.
Concave grating – It is a diffraction grating on a concave mirror surface.
Concave lens – It is also known as a diverging lens. It is a lens which is thinner in the centre than at the edges. It causes light rays passing through it to spread out or diverge. Concave lenses are commonly used in eye-glasses for nearsightedness and in optical instruments like microscopes and telescopes.
Concave mirror – It is also known as a converging mirror. It, is a type of curved mirror where the reflective surface is on the inner side of the curve. This inward curvature causes light rays to converge or come together after reflecting off the mirror.
Concave radius – It refers to the radius of a circle which, if drawn in the opposite direction, forms a concave curve. In simpler terms, it is the radius of the sphere from which a concave surface (like a concave mirror or lens) is a part.
Concavity – It is curved as the inner surface of a sphere. It is the maximum distance from the face of a concave fillet weld perpendicular to a line joining the weld toes.
Concentrate – It is a fine, powdery product of the milling process containing a high percentage of valuable metal. Concentrates are the product of ore dressing operations whereby valuable metals recovered through mining operations are separated from waste rock.
Concentrated ammonia – It normally refers to aqueous ammonia (ammonia gas dissolved in water, also called ammonium hydro-oxide or liquor ammonia) at a high strength of 25 % to 30 % ammonia (NH3) by weight, or anhydrous ammonia (pure liquid or gas ammonia stored under pressure).
Concentrated grain flow runout – It refers to a critical forging defect or geometric condition w3ere the heavily compressed, elongated internal crystal grains (or fibre flow lines) exit or intersect the outer surface of a finished part at an abrupt, sharp angle. Instead of smoothly wrapping around the component’s geometry (such as transitions, shoulders, or fillets), the grain flow is severely packed together and abruptly cut off at a geometric boundary or a parting line.
Concentrated lateral load -It is a horizontal force applied to a specific point or a very small area of a structure (such as a beam, wall, or foundation pile) rather than spread across a wide surface.
Concentrated load – It is a force applied over a very small or localized area of a structural member, and is typically calculated as acting at a single point.
Concentrated mass – It is also called a point mass or lumped mass) in engineering is a simplification where an object’s entire mass is assumed to exist at a single, specific point in space rather than being distributed across a physical volume.
Concentrated moment – It is a moment created by the superposition of two equal but opposite forces separated by a small distance, where the limit is taken as the distance approaches zero while maintaining a constant product with the force.
Concentrated photo-voltaics – It is a solar technology which uses optical devices, such as lenses or curved mirrors, to focus and concentrate direct sunlight onto small, high-efficiency photo-voltaic (PV) cells.
Concentrated radiation – It very frequently refers to concentrated solar radiation. It is radiant energy which has been optically focused from a wide intercepting area onto a considerably smaller receiver area to increase its power flux density and achieve higher working temperatures.
Concentrated solar energy – It is solar energy which has been focused to achieve high temperatures, making it suitable for applications such as the treatment of high-Fe (iron) wastes and competitive with high-energy technologies.
Concentrated solar heat – It refers to thermal energy extracted from solar irradiation by concentrating solar power (CSP) plants, which utilize a solar focusing device to direct solar radiation towards a solar receiver, thereby heating a working fluid for energy generation.
Concentrated solar power – It is a technology which utilizes mirrors to focus sunlight to generate high-temperature heat, which is then converted into electricity through a turbine-driven generator. Concentrated solar power (CSP) systems can include different methods such as trough systems, power tower systems, and dish / engine systems.
Concentrated solar power plants – These are utility-scale facilities which use mirrors or lenses to focus a large area of sunlight onto a small receiver, converting solar energy into high-temperature heat to generate electricity.
Concentrated solar power (CSP) system – It is a technology which uses mirrors or lenses to focus a large area of sunlight onto a small receiver, converting solar energy into high-temperature heat to generate electricity or provide industrial thermal energy.
Concentrated solution – It is a mixture which contains a relatively large quantity of dissolved solute per unit volume or mass of solvent.
Concentrated torque – It is a localized twisting force applied at a specific, single point along a structural element, such as a shaft or a beam, rather than being spread out over a length or area.
Concentrate grade – It is the purity level of a mineral concentrate, expressed as a percentage or assay value, which measures the proportion of the desired valuable element or compound present after separation. It shows how much of the target metal or mineral (such as copper, zinc, or strontium sulphate) is in the final processed product compared to waste rock (gangue).
Concentrating cells – These cells refer to solar cells which use optical systems to focus sunlight onto a small area, allowing for the use of highly efficient multijunction solar cells to convert the concentrated light into electricity. They achieve high efficiency rates but need direct sunlight to operate effectively.
Concentrating collectors – These collectors use mirrors or lenses over a large area to focus solar radiation onto a small absorber (called a receiver). The major types of concentrating collectors are parabolic trough and linear Fresnel.
Concentrating solar collector – It is a system which uses mirrors or lenses to reflect and focus direct beam solar radiation from a large aperture area onto a much smaller receiver or absorber.
Concentrating solar power technologies – These technologies produce electricity by concentrating direct-beam solar irradiance to heat a liquid, solid or gas that is then used in a downstream process for electricity generation. Large-scale concentrating solar power (CSP) plants very frequently concentrate sunlight by reflection, as opposed to refraction with lenses. Concentration is either to a line (linear focus) as in trough or linear Fresnel systems or to a point (point focus) as in central-receiver or dish systems.
Concentrating system – It is an optical or thermal arrangement which gathers solar irradiance, light, or fluid volume from a large collection or aperture area and focuses it onto a much smaller receiver or active area.
Concentration – It is the mass of a substance contained in a unit volume of sample, for example, grams per litre. It is also a process for enrichment of an ore in valuable mineral content by separation and removal of waste material, or gangue. In boiler, it is the weight of solids contained in a unit weight of boiler or feed water. It is also the number of times which the dissolved solids have increased from the original quantity in the feed-water to that in the boiler water because of evaporation in generating steam.
Concentration cell – It is an electrolytic cell, the electromotive force of which is caused by a difference in concentration of some component in the electrolyte. This difference leads to the formation of discrete cathode and anode regions.
Concentration control – It refers to managing or measuring the quantity or proportion of a substance within a specific mixture, solution, or system.
Concentration difference – It is the variation in ion concentration between two regions, which drives the diffusion of ions from the area of higher concentration to the area of lower concentration, notably influencing processes.
Concentration distribution – It is a mathematical function which characterizes the mixing state of a volume by indicating the probability of finding a volume element at a specific concentration. It provides statistical information about the homogeneity or heterogeneity of the reaction volume without detailing the spatial distribution of concentrations.
Concentration equation – It is a mathematical representation of the mass conservation of a chemical component within a system, accounting for changes in concentration because of the convection, diffusion, and chemical reactions over time.
Concentration factor – It is a dimensionless number which quantifies how much a local mechanical stress is amplified at geometric discontinuities (such as holes, notches, fillets, or sharp corners) compared to the nominal or background stress.
Concentration field – It is the spatial and temporal distribution of a solute, particle, or chemical species throughout a medium (such as a liquid, gas, or porous material).
Concentration function – It refers to a mathematical expression or ratio which describes how a physical quantity, such as mass, stress, solar energy, or probability,—intensifies or distributes across a space, material, or system.
Concentration gradient (dC/dx) – It is the spatial slope of the concentration profile at a specific position.
Concentration overpotential – It is the extra voltage difference which arises in an electro-chemical system because of the mass transfer limitations and concentration gradients of reactants and products near the electrode surface.
Concentration polarization – It is that portion of the polarization of a cell produced by concentration changes resulting from passage of current through the electrolyte.
Concentration polarization layer – It is the thin, non-uniform region of fluid immediately adjacent to a membrane or electrode surface where solute or ion concentrations differ considerably from the bulk solution.
Concentration profile – It is the curve which results when the concentration of a chemical species is plotted against position in a material.
Concentration ratio – It is the ratio of the number of atoms (molecules) of a given constituent of a (gas) mixture to the total number of atoms (molecules) in the mixture. For ideal gases the concentration ratio has the same value as the volume fraction or the partial pressure of the constituent.
Concentration test – It evaluates the specific quantity of a solute or particle suspended within a given volume of fluid.
Concentrative internal concentration polarization – It is a phenomenon in asymmetric osmotic membranes (such as in forward osmosis or pressure-retarded osmosis) where solutes accumulate and build up inside the porous support layer of the membrane, leading to a local concentration which is higher than that of the bulk feed solution.
Concentrator – It is a milling plant which produces a concentrate of the valuable minerals or metals. Further treatment is needed to recover the pure metal.
Concentrator mirror – It is a reflective optical surface designed to collect and focus a wide area of radiant energy, typically sunlight, onto a smaller, targeted receiver area. Concentrator mirrors are reflective surfaces designed to focus sunlight onto a small area, and their performance can be affected by different errors such as specularity, surface slope, shape, and tracking errors, which degrade the optical efficiency of the system.
Concentrator plant – It is an industrial processing facility which separates valuable minerals or resources from raw, unrefined feed material (such as mined ore) to produce a high-grade concentrate while discarding waste material (tailings). In mining engineering, a concentrator plant (also called a mill or separation plant) upgrades raw run-of-mine (ROM) ore before it is sent to a smelter, refinery, or chemical plant. In renewable energy and thermal engineering, a concentrator plant refers to a concentrated solar power (CSP) facility.
Concentrator system – It is an apparatus which uses optical components, such as lenses or mirrors, to collect sunlight or electro-magnetic radiation over a large area and focus it onto a much smaller receiver or active surface. In mineral processing and metallurgy, a concentrator system can also refer to a mechanical plant circuit (using grinding, crushing, and flotation) designed to separate and enrich valuable minerals from ore.
Concentric – It means having the same centres.
Concentric annular duct – It is a fluid flow and heat transfer geometry formed by two cylindrical tubes sharing a common central axis (concentric).
Concentric annulus – It is the ring-shaped 3D or 2D region bounded by two circular cylinders or circles that share the exact same central axis or center point.
Concentric circles – These are two or more circular cross-sections, cylindrical shells, or rotation axes which share the exact same centre point or axis of rotation, but have different radii.
Concentric design – It refers to an arrangement where two or more features, components, or shapes share a common central axis or origin.
Concentric layers – These layers refer to multiple structural, thermal, electrical, or geometric rings, shells, or cylinders which share the exact same central point or common axis but have different radii or sizes.
Concentricity – It is conformance to a common centre as, for example, the inner and outer walls of round tube. It is a geometric property describing the condition where two or more cylindrical or spherical features share a common, perfectly aligned central axis. In the production of metal components like tubes, pipes, and shafts, concentricity represents the consistency of wall thickness or the perfect alignment of outer and inner diameters.
Concept – It is the initial phase of systems design where project teams identify stakeholder needs, establish core problem statements, and define measurable performance goals before building any physical solution.
Concept design – It is the initial phase of product or system development which translates abstract ideas and user requirements into a high-level physical or functional model. It is a critical stage in the design process which culminates extensive investigative work and solution generation, showing the optimal method to address a design challenge while aligning with available technology, funding, and skills. It serves as a visual representation to demonstrate the product’s attributes to potential clients and is to effectively communicate the design’s functionality and performance.
Concept drawing – Concept drawing is a drawing, frequently freehand, which is used as a quick and simple way of exploring initial ideas for designs. This drawing is not intended to be accurate or definitive, merely a way of investigating and communicating design principles and aesthetic concepts. Concept drawings are more like the first draft of a construction project which is made in the first instance. They are not very detailed or distinguished. These drawings are like rough sketches. They are more prominently used to describe an overview of the object.
Concept, laser – A laser is a device that emits a beam of coherent light generated by an optical amplification process. A laser beam is highly energetic, nearly monochromatic, and unidirectional because of its coherence. These characteristics confer it with a substantial potential to produce very high-power densities and make it suitable in many metallurgical applications, like welding, cutting, drilling, and heat treatment.
Concept mapping – It is a visual tool used to organize, structure, and model complex technical knowledge by connecting fundamental concepts with labelled relationships.
Concept of operations – It is a user-oriented document which describes how a proposed system is to be used in its intended environment to accomplish specific missions or goals. It acts as a non-technical bridge between the vague operational needs of stakeholders and the precise technical requirements used by developers.
Concept selection method – It is a group process of selecting a design concept or material in which the selection criteria and concepts are arranged in matrix form, and for each criterion the concepts are compared one at a time to a datum (reference) concept. It is frequently called the Pugh concept selection method.
Concept sketch – It is a quick, freehand drawing used to explore, test, and communicate early design ideas before making precise technical models.
Concept to completion – It means managing or performing every single step of a project from the initial idea all the way to the final delivery. It is a method of ensuring that the project is fully supported from start to finish.
Conceptual analysis – It involves distinguishing terms, analyzing their meanings, and representing fundamental entities or phenomena within a discipline. It focuses on understanding abstract ideas or mental images represented by theoretical terms, constructing a framework for making sense of the world, and articulating concepts within an ontology.
Conceptual design – It is the initial stage of the engineering design process in which a physical concept of the product is developed. The physical concept includes the principles by which the product will work and an abstract physical embodiment that will employ the principles to achieve the desired functions.
Conceptual design phase – It is the first major stage of the engineering and design process. It defines the core idea, system needs, and high-level feasibility of a project before detailed physical design or construction begins.
Conceptual engineering – It is a philosophical method which assesses, improves, designs, or replaces concepts and words to better serve practical and theoretical goals.
Conceptual map – It is a visual diagram which represents a set of core technical concepts (nodes) and explicitly defines how they relate to one another (labeled arrows or linking phrases) within a specific engineering domain. Conceptual map is a visual representation of a set of concepts and their relationships within a knowledge domain, facilitating knowledge model creation, visualization, and discussion among stakeholders with diverse interpretations.
Concern – It is a specific area of interest, functionality, behaviour, or risk which impacts how a system is designed, built, and operated.
Conchoidal fracture – It is a break or fracture of a brittle material which does not follow any natural planes of separation. Conchoidal fracture is defined as a fracture with smooth, curved surfaces, typically slightly concave, showing concentric undulations resembling the lines of growth of a shell. Materials which break in this way include quartz, chert, flint, quartzite, jasper, and other fine-grained or amorphous materials with a composition of pure silica, such as obsidian and window glass, as well as a few metals, such as solid gallium.
Concise form – It is a simplified representation which summarizes a complex system, structure, or function using a minimal set of parameters or core equations to enable efficient analysis and mathematical modelling.
Conciseness – It means communicating technical information clearly, accurately, and completely using the fewest words or data points possible without losing essential meaning.
Concrete – It is a composite building material made from a mixture of sand, gravel, crushed rock, or other aggregates (coarse and fine) held together in a stone like mass with a binder such as cement and water. The stone like mass is formed due to the hydration of cement and eventually due to its hardening. Sometimes one or more admixtures (plasticizers, super plasticizers, accelerators, retarders, Pozzolanic materials, air entertaining agents, fibres, polymers and silica furies) are added to change certain characteristics of the concrete such as its workability, durability, and time of hardening. Hardened concrete has a high compressive strength and a very low tensile strength.
Concrete admixture – It is a material other than water, aggregates, cement, and fibre reinforcement added to a concrete batch before or during mixing to modify its fresh, plastic, or hardened properties. These ingredients fine-tune characteristics like flowability, setting time, and strength.
Concrete application – It refers to the specific structural, architectural, or environmental use-case for which a tailored concrete mix and placement method are designed. Concrete applications refer to the different uses of concrete as a construction material, which include making pavements, architectural structures, foundations, roads, bridges, parking structures, and walls. Additionally, concrete can be improved with additives to improve its properties and durability in these applications.
Concrete batching – It is the process of measuring the required quantities of concrete ingredients, cement, fine aggregate (sand), coarse aggregate (stone or gravel), water, and chemical admixtures, either by mass (weight) or by volume, and introducing them into a mixer according to a predetermined mix design.
Concrete beam – It is a horizontal structural element designed to carry transverse loads and resist bending (flexure) and shear forces by transferring weight to vertical supports like columns or walls.
Concrete bridge – It is an engineered infrastructure structure designed to span physical obstacles using plain, reinforced, or prestressed concrete as its main structural material.
Concrete building – It is a structure where vertical elements (such as columns and load-bearing walls) or lateral-force-resisting systems are mainly constructed from concrete to support gravity and environmental loads.
Concrete carbonation – It is a chemical process where carbon di-oxide from the air enters the concrete and reacts with calcium hydroxide to form calcium carbonate.
Concrete code – It is a set of official standards, rules, and guidelines used to design, mix, test, and build safe and long-lasting concrete and reinforced concrete (RCC) structures.
Concrete column – It is a vertical structural member designed mainly to resist compressive loads and safely transfer weight from slabs and beams down to the foundation.
Concrete components – These refer to the important constituents of concrete, mainly including aggregate, cement, and water, which collectively define the material’s properties such as load carrying capacity and durability. Their proportions and interactions are important for determining the overall performance and quality of concrete.
Concrete composition – It refers to the specific combination of materials and admixtures used to create concrete, which considerably influences its final characteristics, including extrudability, flowability, and susceptibility to cracking and discontinuity during the 3D printing process. The selection and optimization of these materials are important for achieving desired mechanical properties and durability.
Concrete construction industry – It is the sector of civil engineering and building construction which focuses on designing, producing, transporting, placing, curing, and maintaining structures built from concrete, a composite material made of cement, water, fine and coarse aggregates, and chemical admixtures.
Concrete core – – It is a central, reinforced concrete shaft or contiguous wall system built into tall buildings which acts as the main vertical and lateral load-bearing backbone. It resists wind, gravity, and earthquake forces by functioning as a high-strength shear wall cage. It is also a cylindrical plug or core drilled directly out of a hardened concrete slab, wall, or footing using a diamond-segmented bit.
Concrete cover thickness – It is the shortest distance measured from the exposed outer surface of a reinforced concrete member to the nearest surface of the embedded steel reinforcement bar (rebar).
Concrete cracking – It occurs when internal or external forces induce tensile stresses which exceed the concrete’s tensile strength.
Concrete crushing – It is the mechanical process of breaking down large pieces of old concrete, slabs, foundations, or demolition debris into smaller, manageable aggregate fragments.
Concrete dam – It is a heavy hydraulic structure built from mass concrete or reinforced concrete across a river to retain water, generate hydroelectric power, supply irrigation, or control floods.
Concrete density – It is the mass of concrete per unit volume, typically measured in kilograms per cubic meter or kilonewtons per cubic meter.
Concrete deterioration – It is the gradual degradation of concrete’s structural integrity, load-capacity, and appearance over time because of the physical, chemical, or biological processes.
Concrete durability– It is the ability of concrete to resist weathering action, chemical attack, and abrasion while maintaining its desired engineering properties and structural integrity over its intended service life.
Concrete element – It is an individual structural component made of concrete used to build a structure. These elements transfer loads safely to the ground.
Concrete encased steel column – It is a composite structural member made by embedding a structural steel shape inside a reinforced concrete cag. . Concrete encased steel (CES) column is a form of composite columns which synergize the merits of steel and concrete materials, which comes in square, rectangular and circular cross-sections, etc. Different from CFST (concrete-filled steel tube) columns, the steel section of fully encased Concrete encased steel columns is completely surrounded by concrete, hence eliminating the need of fire and corrosion protection. The embedded steel section functions as temporary load-bearing member at the construction stage hence expediting the construction process, and it offers excellent shear resistance and energy dissipation capacity.
Concrete-filled tubular (CFST) column – It is a composite structural member made by pouring concrete inside a hollow exterior steel pipe. Steel outer shell acts as a permanent mould (formwork) and outside reinforcement for the column. Concrete core fills the centre to resist heavy downward pressing (compression) loads. Both the steel and concrete lock together and share the load, making the total structure much stronger than either material alone.
Concrete filled steel tube – It is a structural system which utilizes an external steel tube to confine concrete infill, which simultaneously acts to prevent inward buckling of the steel tube. This configuration considerably improves the structural properties compared to the separate components of steel and concrete.
Concrete girder is a large, primary horizontal structural member—made of reinforced or prestressed concrete, which supports smaller beams or bridge decks and transfers heavy loads to columns, piers, or abutments.
Concrete girder beams – These beams are structural elements used in bridge engineering, mainly made of reinforced concrete, which offer advantages such as simple structure, low cost, and convenient construction, although they are susceptible to issues like cracking and deterioration under vehicle loads and harsh environments.
Concrete industry – It refers to the comprehensive economic and technical sector involved in the production, processing, transport, placement, and lifecycle management of concrete and its constituent materials.
Concrete infrastructure – It refers to the large-scale physical structures and foundational systems built mainly using concrete to support the economic, social, and functional needs of society.
Concrete liner – It is a structural or protective layer of concrete applied to the inner surface of an excavation, tunnel, pipe, or shaft.
Concrete lining – It is an impermeable or structural layer of cast-in-place, precast, or sprayed concrete applied to the interior surfaces of underground openings (such as tunnels) or fluid-conveying channels (such as canals) to provide support, prevent erosion, and stop water leakage.
Concrete market – It refers to the economic sector which produces, distributes, and consumes concrete and its constituent materials (cement, aggregates, water, and chemical / mineral admixtures).
Concrete masonry unit – It is a standard-sized, precast rectangular block made from Portland cement, water, and aggregates like sand or crushed stone, used in structural and architectural building.
Concrete matrix – It is also called cementitious matrix. It is the continuous binder phase composed of cement, water, fine aggregate (sand), and sometimes admixtures which chemically reacts, hardens, and holds coarse aggregates and reinforcements together.
Concrete mixer is a mechanical device that homogeneously – It combines cement, aggregates (such as sand and gravel), water, and chemical admixtures to produce fresh concrete.
Concrete pavement – It is a type of rigid pavement made mainly from Portland cement concrete (PCC) which distributes vehicle loads across a wide area through its high flexural strength and stiffness. Common types of concrete pavements are jointed plain concrete pavements (JPCP), jointed reinforced concrete pavements (JRCP), continuously reinforced concrete pavements (CRCP), and pre-cast concrete pavements (PCP).
Concrete piles – These piles are produced with reinforced cement concrete (RCC). These piles are either pre-cast or cast in- situ.
Concrete pipe – It is a rigid cylindrical conduit made from a blend of Portland cement, water, sand, and coarse aggregates to support heavy external earth loads and traffic weights independently of surrounding. Concrete pipes are cylindrical structures used for drainage purposes, including storm water, road culverts, and sewers, which are typically buried underground and need measures to ensure their structural safety and durability because of the susceptibility to corrosion. Their expected service life ranges from 80 years to 100 years, influenced by factors such as design, installation, and environmental conditions.
Concrete placement – It is the process of pouring and finishing concrete in a manner which maintains the quality and integrity of the material, ensuring proper handling techniques to avoid issues such as segregation and reduced bond strength.
Concrete plant – It is also known as a concrete batching plant or batch plant. It is an industrial facility which combines raw ingredients, such as cement, sand, aggregates (gravel or crushed stone), water, and chemical admixtures, in exact, computer-controlled proportions to produce consistent, high-quality concrete.
Concrete pores – These are microscopic to macroscopic voids or empty spaces inside the hardened cement paste and aggregate matrix which form during mixing, casting, and cement hydration.
Concrete preparation – It is frequently called concrete surface preparation. It is the process of cleaning, treating, and profiling a concrete surface before applying a coating, overlay, repair material, or sealant. Its main purpose is to remove contaminants and create a rough surface profile, ensuring a strong, permanent mechanical bond between the existing concrete and the new material. Without proper preparation, new coatings or repairs almost always fail and delaminate.
Concrete prism – It is a rectangular or square-shaped cast-concrete or mortar test sample used to evaluate material properties, such as flexural strength, compressive strength, or alkali-silica reaction (ASR) expansion. It is used for assessing alkali-silica reaction (ASR) expansion in concrete, recognized as the most dependable because of its closer resemblance to real structures compared to other methods, although it needs a long testing duration of up to two years.
Concrete production – It is the sequential process of measuring, mixing, transporting, placing, compacting, and curing raw ingredients, mainly cement, water, fine aggregates (sand), coarse aggregates (gravel or crushed stone), and chemical admixtures, to form a durable, load-bearing composite structure.
Concrete quality – It is a measure of how well a concrete mix meets specified standards for strength, durability, workability, and performance over its intended service life.
Concrete, refractory – It is suitable for use at high temperatures composed of hydraulic cement (calcium aluminate cement) as the binding agent.
Concrete removal – It is the controlled cutting, breaking, dislodging, and clearing of unwanted, damaged, or deteriorated concrete from a structure or site.
Concrete repair – It is the process of diagnosing, removing, and replacing damaged or deteriorated concrete to permanently restore a structure’s load-bearing capacity, integrity, and extended service life.
Concrete rheology – It is the scientific study of the flow and deformation characteristics of fresh cement concrete, focusing on how the material moves and behaves when subjected to external forces.
Concrete samples – These samples are specifically designed samples of concrete, such as cylinders and notch beams, which are experimentally tested under controlled laboratory conditions to assess their compressive strength and other properties. These samples refer to a collection of multiple individual test samples (typically three cubes or cylinders) taken from a single batch of fresh concrete to evaluate its quality, workability, and strength.
Concrete shear capacity – It is the maximum shear force a concrete structural member can safely resist before experiencing diagonal cracking or sudden, brittle structural failure.
Concrete slab – It is a flat, horizontal structural element, typically made of cast or reinforced concrete, which has a very small thickness compared to its length and width. It acts as a main flexural (bending) member to provide flat, useful working surfaces such as floors, ceilings, roof decks, and bridge decks.
Concrete sleeper – It is also called a railroad tie. It is a heavy, rectangular structural support element laid transversely under railway tracks to hold the steel rails in place, maintain the correct gauge (distance between rails), and distribute train loads down to the ballast and subgrade.
Concrete slurry – It is a semi-liquid by-product created when cutting, grinding, drilling, or polishing concrete with water.
Concrete storage – It refers to how cement, sand, and coarse aggregates are protected before mixing to maintain quality.
Concrete storage structures – These are facilities, such as reinforced concrete (RCC) tanks, reservoirs, coal silos, and high-temperature thermal storage blocks, designed to safely contain liquids, chemicals, water, or dry bulk materials.
Concrete structure – It is a construction made mainly of concrete, a composite material formed by mixing cement, water, sand, and coarse aggregates (like gravel or crushed stone). Since plain concrete handles heavy compressive forces well (pushing forces) but is weak against tensile forces (pulling or bending forces), engineering designs typically incorporate reinforcement.
Concrete substrate – It is the underlying or base concrete surface onto which a repair material, coating, overlay, waterproof membrane, screed concrete, or fibre-reinforced polymer (FRP) is applied. It acts as the structural anchor which transfers mechanical loads, shear stress, and bond forces between the new layer and the existing structure.
Concrete technology – It studies the properties, production, testing, mix design, and practical application of concrete in construction. It is the field which encompasses the development and application of concrete materials, including innovations like ultra-high-performance concrete (UHPC), which improves structural designs by offering exceptional properties that enable reduced-weight structures and improved aesthetics.
Concrete temperature – It refers to the thermal state of the concrete mixture during its fresh, setting, and curing stages, which directly dictates the rate of cement hydration, workability, and long-term structural integrity.
Concrete ties – These are precast concrete components used in railways, designed with a monoblock structure which incorporates prestressed members to resist bending, providing a rigid connection between the rail and the tie. They typically weigh between 270 kilograms to 360 kilograms and are utilized extensively for their durability and stability in different railway applications.
Concrete tunnel – It is a subterranean or underwater structural passageway made with concrete linings or cast-in-place concrete walls and slabs which withstand earth, water, and live traffic loads.
Concurrent engineering – It is also known as concurrent design and manufacturing. It is a work methodology emphasizing the parallelization of tasks, which is sometimes called simultaneous engineering or integrated product development using an integrated product team approach. It is a method of designing and developing products, in which the different stages run simultaneously, rather than consecutively. It decreases product development time and also the time to market, leading to improved productivity and reduced costs.
Concurrent grain growth – It is the increase in average crystal size which happens at the same time as another ongoing metallurgical or physical process.
Concurrent heating – It is the application of supplemental heat to a structure during a welding or cutting operation.
Concurrent processing – It is the ability of a system to handle multiple tasks or processes at the same time by overlapping their execution periods or rapidly switching between them.
Concurrent programme – It is a programme which allows multiple processes or threads to execute simultaneously, leading to non-deterministic behaviour where the same input can produce different correct outputs. Testing concurrent software involves analyzing outputs from different synchronization sequences to address challenges related to communication, synchronization, and efficient execution.
Concurrent programming – It is a software engineering paradigm in which a programme is structured as multiple independent tasks or processes which run in overlapping time periods.
Concurrent transmission – It refers to the process where multiple transmitters broadcast signals simultaneously on the same frequency or channel within the same network area.
Condensable gas – It is a gas phase substance which can turn into a liquid when its temperature drops below its dew point or when the pressure changes at operating temperatures and pressures.
Condensate – It is the liquid phase produced by the condensation of steam. It is the condensed water resulting from the removal of latent heat from steam.
Condensate film – It is the thin, continuous layer of liquid which forms on a solid surface when saturated vapour condenses and completely wets the wall.
Condensate, gas – Gas condensate is a hydro-carbon liquid stream separated from natural gas, consisting of higher-molecular-weight hydro-carbons which are recovered as liquids during the processing of natural gas. It typically contains hydro-carbons boiling up to C8 (8 carbon atoms) and is got through separation processes in gas-processing plants.
Condensate oil – It is a low-density, ultra-light liquid hydro-carbon mixture which exists as a gas in underground reservoirs and condenses into a liquid when temperature and pressure drop at the surface or in production facilities.
Condensate polishing unit – It consists of a series of ion exchange units designed to improve water quality in power stations by removing contaminants from condensate, hence improving boiler efficiency and extending turbine life. It typically includes different types of cation and anion exchangers and operates at high flow rates.
Condensate separator – It removes liquid water, oil, and mist from steam, compressed air, or gas streams to protect downstream equipment.
Condensate stabilization – It is the process of removing volatile light-end hydro-carbons (C1 to C4, mainly methane and ethane) from liquid hydro-carbon condensate streams to reduce vapour pressure and ensure safe storage and pipeline transport.
Condensate system – It is a system designed to manage and potentially reuse the liquid produced when steam or another gas condenses. It typically involves collecting, transporting, and sometimes returning the condensate to the boiler, or using it for other purposes like attemperation or chemical feed.
Condensation – It is defined as the change in the physical state of water vapour to liquid water. It is reverse of vapourization.
Condensation cure silicone – It is a type of silicone material that cross-links through a condensation reaction, typically needing moisture from the air to initiate the curing process, during which acetoxy groups are hydrolyzed to form silanols which facilitate further cross-linking. This process is normally utilized in one-part RTV (room temperature vulcanizing / vulcanization) sealants and adhesives.
Condensation heat transfer – It is a high-efficiency thermal process where vapour cools and turns into liquid, releasing large quantities of latent heat.
Condensation heat transfer coefficient – It is a proportionality constant which measures how effectively heat is transferred from a condensing vapour to a solid surface as the vapour turns into a liquid.
Condensation nuclei – These are tiny solid or liquid suspended particles in the air which provide a physical surface for water vapour to condense upon. In environmental, mechanical, and chemical engineering, condensation nuclei (CN) act as heterogeneous nucleation sites, allowing water vapour to transition into liquid or ice droplets at much lower relative humidity or supersaturation levels than are needed for spontaneous (homogeneous) nucleation.
Condensation nuclei counter – It is also known as a condensation particle counter (CPC) or Aitken nuclei counter. It is an instrument which measures the number concentration of tiny airborne aerosol particles (typically sub-micrometer or nano-scale).
Condensation oscillation – It is the periodic, fluctuating behaviour of vapour (such as steam) collapsing as it contacts a subcooled liquid, leading to repetitive growth, shrinkage, and pressure pulses at the vapour-liquid interface.
Condensation particle counter – It is also called a condensation nucleus counter, It is an instrument which detects and counts ultra-small aerosol particles (down to 1 nano-meter to 3 nano-meters in size) by growing them into larger droplets through vapour supersaturation so they can be counted using optical light-scattering optics.
Condensation polymer – It is a macro-molecule formed through step-growth polymerization where bi-functional or tri-functional monomer units react with each other, releasing small by-product molecules, such as water, methanol, or hydrogen chloride, during each joining step.
Condensation polymerization – It is a chemical reaction in which two or more molecules combine, with the separation of water or some other simple substance. If a polymer is formed, the process is called poly-condensation.
Condensation pressure – It is also called condensing pressure. It is the pressure at which a refrigerant or gas turns into a liquid inside a system like a condenser or refrigeration cycle. It is the saturation pressure corresponding to the temperature at which a vapour changes phase into a liquid when interacting with a cooling medium (such as air or water).
Condensation process – It is the cooling of a waste gas stream below the dew point of its vapours to allow the vapours to condense on a heat exchanger surface, frequently influenced by factors such as flow velocities and temperature profiles. It is normally used in applications like solvent recovery, sometimes needing extremely low temperatures. Condensation process is a phase change process where a substance converts from a vapour (gas) state into a liquid state by removing latent heat.
Condensation reaction – It is a chemical process where two molecules or functional groups combine to form a single, larger molecule while simultaneously eliminating a small by-product molecule, very frequently water, hydrogen chloride (HCl), alcohol, or ammonia (NH3).
Condensation shock – It is a rapid, localized transition in a supersonic two-phase flow where sudden gas condensation releases latent heat, causing a sharp increase in pressure and temperature alongside a drop in the fluid’s Mach number.
Condensation stain – It is the superficial oxidation of the surface with a water film, in the absence of circulating air, held between closely adjacent metal surfaces.
Condensation system – It is a pollution control technology which separates and recovers volatile organic compounds or hazardous air pollutants from gas streams through the processes of condensation and partial solidification, frequently utilizing liquid nitrogen to achieve low temperatures and control emission concentrations.
Condenser – It is an equipment which used to cool exhaust steam from a turbine below the boiling point so that it can be returned to the heat source as water. It is also a system of lenses or mirrors designed to collect, control, and concentrate light.
Condenser aperture – In electron microscopy, it is an opening in the condenser lens controlling the number of electrons entering the lens and the angular aperture of the illuminating beam.
Condenser duty – It is the quantity of heat gained by the cooling medium, typically cooling water, during the condensation process, and is calculated based on the mass flow rate of the cooling water and the difference in enthalpy of the cooling water supply and return.
Condenser lens – It is a device which is used to focus radiation in or near the plane of the object.
Condenser load – It is the total rate of heat which a condenser is to remove from a working fluid (such as refrigerant or steam) to turn it from a gas into a liquid.
Condenser microphone – It is also called a capacitor microphone. It is an electro-acoustic transducer which converts sound pressure waves into an electrical signal using the physical principles of a variable-plate capacitor.
Condenser outlet temperature – It is the temperature of the working fluid (such as a refrigerant, water, or process gas) as it leaves the outlet of a condenser unit.
Condenser pressure – It is the pressure at which a vapour or gas phase-changes into a liquid inside a condenser by releasing its latent heat.
Condenser region – It typically refers to the distinct physical or thermodynamic sections where specific heat-transfer phases occur as the fluid moves through the unit. A complete condensation process in a heat exchanger is normally divided into three main operational regions namely de-superheating zone, two-phase (condensation) zone, and subcooling zone (single-phase liquid).
Condenser section – It is the specific portion of a heat exchanger or thermal system where a vapour (such as steam or refrigerant) flows and turns into a liquid by releasing its latent heat to a cooling medium like air or water.
Condenser temperature – It is the saturation temperature of a working fluid (such as a refrigerant or steam) corresponding to its pressure inside the condenser during a phase change from gas to liquid.
Condenser tube – The term ‘heat-exchanger tube’ is preferred, unless specific reference to a condenser application is intended.
Condenser vacuum – It is the sub-atmospheric pressure maintained inside a steam condenser shell. It is created when exhaust steam from a turbine condenses into water, causing a massive drop in volume and forming a low-pressure space below atmospheric pressure.
Condensing effect – It refers to the physical phenomenon where a vapuor (such as steam) transitions into a liquid state when its temperature drops below its saturation point (dew point) or when it contacts a cooler surface, releasing its latent heat of vapourization.
Condensing flow – It is a two-phase fluid motion where a vapour (such as steam or refrigerant) transitions into a liquid as it cools and releases latent heat of vapourization.
Condensing pressure – It is the specific pressure at which a vapour (such as a refrigerant or steam) turns into a liquid as it releases latent heat to a cooling medium like air or water. It marks the high-pressure side of a thermodynamic or refrigeration cycle where gas transitions into a liquid at a saturation point linked to temperature.
Condensing rings – These are also known as chilling rings or condensation rings. These are specialized metal inserts or internal thermal rings used in casting moulds to rapidly cool specific sections of molten metal, producing a dense, fine-grained structure.
Condensing steam – It is the process where water vapour changes phase into liquid water while releasing its latent heat at a near-constant saturation temperature.
Condensing temperature – It is the saturation temperature at which a vapour changes state into a liquid at a given pressure inside a condenser. It is the specific temperature where a working fluid (like a refrigerant) releases its latent heat and turns from a gas into a liquid.
Condensing turbine – It is a type of steam turbine where the exhaust steam is condensed back into water, typically in a condenser, to maximize energy extraction and improve overall efficiency. This process allows for a closed-loop system where the condensate can be recycled back into the boiler.
Condensing vapour – It is a gas or vapour stream which transitions into a liquid state upon coming into contact with a cooler surface or dropping below its dew point, releasing its latent heat of vapourization in the process.
Conditional density function – It defines the probability distribution of a random variable when the value of another random variable or condition is already known or fixed.
Conditional expectation – It is the expected (average) value of a random variable calculated after accounting for known information or conditioning on another variable or event. It represents the best possible estimation or prediction of an unknown quantity given available measurement.
Conditional independence – It is a state where two events or random variables become statistically independent of each other once a third variable or event is known or fixed.
Conditional likelihood – It refers to the likelihood of an observed data set or system state given a set of known inputs, constraints, or nuisance parameters.
Conditional loss – It is the loss distribution function of a portfolio calculated based on a specific forecast of a common factor, which reflects the expected outcomes given particular assumptions about future values. It refers to the expected loss, probability of failure, or energy / financial deficit of a system calculated under specific, given conditions or assumptions.
Conditional mathematical expectation – It is the expected value of a random variable given that a specific condition, event, or known information has occurred. In applications such as signal processing, reliability, and stochastic control, it serves as the optimal mean-squared error estimate of an unknown variable based on available measurements.
Conditional mean spectrum – It is a target response spectrum in earthquake engineering which shows the expected (mean) spectral acceleration at all vibration periods, conditioned on the occurrence of a target spectral acceleration at a specific period of interest.
Conditional operator – It is also called ternary operator. It is a programming construct which evaluates a Boolean condition and selects one of two alternative expressions depending on whether the result is true or false.
Conditional probability – It is the likelihood that a specific event (A) occurs, given that a prior or related event (B) has already happened.
Conditional probability density – It is the probability density function of a random variable ‘X’ given that another random variable ‘Y’ takes on a specific value.
Conditional probability density function – It describes the probability distribution of a continuous random variable given that a second random variable takes a known, fixed value.
Conditional probability of failure – It defines the likelihood of an item failing within a specific time interval, given that it has survived up to that point. It is a special case of conditional probability where the event of interest is the item’s failure, and the condition is its prior survival. Conditional probability of failure measures the probability which an item entering a given age interval fails during that interval. The item shows wear-out characteristics if the conditional probability of failure increases with age. If the conditional probability of failure is constant with age, the resulting failure distribution is exponential and applies to the majority of facilities equipment.
Conditional reliability – It is the probability that a piece of equipment is going to operate without failure for an additional period of time, given that it has already operated for a certain duration without experiencing failure. It is mathematically represented as the complement of the conditional probability of failure.
Condition assessment – It is a systematic, documented evaluation of the physical and functional state of an asset, structure, equipment, or facility. It measures current health, detects localized faults, and determines if an asset is safe and ‘fit for continued service’ under operating loads.
Condition based maintenance – It is a set of maintenance actions based on the real-time or near real-time assessment of equipment conditions, which is achieved from embedded sensors and / or external tests and measurements, taken by portable equipment and / or subjective condition monitoring.
Condition-based scrap melting system – It is a dynamic, automated industrial framework which regulates and optimizes the recycling and melting of metal scrap (such as steel or aluminum) based on real-time process conditions, material characteristics, and equipment states, rather than adhering to rigid, pre-set operational diagrams or time-based schedules. Instead of treating every batch of scrap the same, the system continuously reads incoming data and adjusts variables like electrical power, chemical energy injection, and furnace dynamics on the fly.
Condition coverage – It is a testing criterion in software engineering which ensures all possible conditions in a decision statement are tested, typically involving Boolean variables or expressions to achieve thorough testing.
Conditioned problem – It refers to how sensitive a problem’s solution is to small changes or errors in its input data. It is a property of a problem where it is considered ill-conditioned if a small change in the data causes a large change in the solution, while it is well-conditioned if such changes have minimal effects on the solution. The conditioning is dependent on the specific set of data used.
Condition estimator – It is a metric or numerical algorithm which tests how close a system of equations or a coefficient matrix is to being ill-conditioned.
Condition evaluation – It is the systematic process of inspecting, measuring, and analyzing the physical and functional state of an asset, structure, or equipment to determine its current health and fitness for continued service.
Conditioning – It refers to the process of modifying, treating, or adjusting raw materials, environmental air, or electrical / analog signals to meet specific operational standards before they are used, stored, or processed further. It is also the removal of surface defects (seams, laps, pits, etc.) from steel. It is normally done when the steel is in semi-finished condition (bloom, billet, slab). It can be accomplished after an inspection by chipping, scarfing, grinding, or machining.
Conditioning equipment – It refers to devices and systems designed to modify the characteristics of something, like a signal, material, or environment, to meet specific needs or standards. This can involve several processes like filtering, stabilizing, chipping, scarfing, grinding, machining, or adjusting properties.
Conditioning facility – It is a facility which exists for the purpose of changing the chemical or physical form of a material to make it suitable for a specific purpose. It is also applied in waste management to a facility for processing waste to condition it for storage, transport and disposal.
Conditioning function – It is the process of manipulating a raw, weak, or noisy sensor signal to make it clean, accurate, and compatible with a controller or data acquisition system.
Conditioning heat treatment – It is a preliminary heat treatment used to prepare a material for a desired reaction to a subsequent heat treatment. For the term to be meaningful, the exact heat treatment is to be specified.
Conditioning model – It refers to a mathematical, computational, or physical framework used to transform, adjust, or regularize raw data, signals, or system inputs so they match the requirements of a downstream process, control system, or analysis tool.
Conditioning procedure – It is a mechanical treatment applied to viscoelastic materials to establish a standard, reproducible microstructural state, ensuring comparability of mechanical property characterization results across different experiments and laboratories. This typically involves applying a maximum load for a predetermined time, followed by a prolonged recovery period, repeated until consistent load-extension results are achieved.
Conditioning radioactive waste – It is the process of making the radioactive waste chemically stable and safe for transport, storage, or disposal. The process involves changing the waste into a solid form which is insoluble in water.
Conditioning system – It is the arrangement of processes used to adjust the temperature and pressure of carbon di-oxide (CO2) streams, which includes compression, cooling, water removal, and the treatment of unwanted components to prepare carbon di-oxide for transport.
Condition management – It is the systematic practice of continuously monitoring, assessing, and managing the real-time health and state of physical assets or infrastructure to optimize performance, prevent unplanned failures, and schedule timely interventions.
Condition monitoring system – It is the process of tracking machinery health and operational parameters in real time or through periodic checks to detect early signs of equipment degradation before a breakdown occurs.
Condition number – It is a measure of the sensitivity of the system to small changes in its elements, indicating the potential for error magnification in solutions. A large condition number indicates serious collinearity, which can lead to substantial variations in the solution from minor perturbations in the input data.
Conditions for acceptance – These are the requirements of a receiving body in relation to the parameters with which the material is to comply in order for the material to be accepted into the receiving body’s facility.
Conductance – It is the capacity of a medium, normally expressed in mhos, for transmitting electric current. It is the reciprocal of resistance. In case of a gas, it is the ratio of the through put (under steady state, conservative conditions) of a gas flowing through a conduit or an orifice to the difference in the partial pressures of the gas at the two ends of the conduit or on the two sides of the orifice, expressed in volume units per unit time, such as cubic metres per second.
Conductance peak – It is a sharp local maximum in the electrical conductance of a nano-scale or quantum electronic device (such as a quantum dot, single-electron transistor, or point contact) plotted as a function of gate voltage, source-drain voltage, or magnetic field.
Conductance-time curves – These are graphical plots which monitor changes in electrical (or thermal) conductance as a function of time to study the kinetics of solid-state phase transformations, precipitation hardening, and atomic-level mechanical interactions. Since a metal’s electrical resistivity changes based on its crystal lattice, defects, and chemical phases, measuring how conductance evolves over time allows metallurgists to track internal microstructural transformations non-destructively.
Conducted emissions – These are unwanted electro-magnetic energy or electrical noise generated by an electronic device which travels through physical conductors, such as power cords, signal cables, and PCB (printed circuit board) traces, rather than radiating through open space.
Conducted experiment – It is a structured, planned procedure carried out under regulated conditions to test a hypothesis, observe cause-and-effect relationships, and gather empirical data.
Conducted measurements -These measurements specifically refer to test and evaluation methods where signals or disturbances are measured through direct physical or conductive connections (such as cables, wires, or circuit ports) rather than through wireless or spatial radiation.
Conductimeter – It is a device used to measure the electrical conductivity of solutions. It is noamally utilized in flow systems for conductimetric determinations, though it typically lacks selectivity and can need pre-treatment methods for accurate analysis.
Conducting plate – It is a flat, thin structural or electrical element, made of a material like metal or graphite, where free charges, heat, or electrical currents can move easily across its surface.
Conducting polymers – These are organic macro-molecules which combine the mechanical flexibility and lightweight nature of plastics with the electrical conductivity and optical properties of metals or semi-conductors.
Conducting salt – It is a salt added to the solution in order to increase its conductivity.
Conducting substrate – It involves designing and tailoring the electrical, thermal, optical, and mechanical properties of a base support material, such as silicon, glass, polymers, or metal-coated layers, so it can actively transport charge or transmit signals in devices like solar cells, sensors, and microelectronics.
Conduction – It is the transmission of heat through and by means of matter unaccompanied by any obvious motion of the matter. The transfer of heat through matter (i.e., solids, liquids, or gases) is without bulk motion of the matter. In another ward, conduction is the transfer of energy from the more energetic to less energetic particles of a substance due to interaction between the particles.
Conduction band – It is the lowest-lying electron energy band for electrical insulators and semi-conductors which is empty of electrons at 0 K. Conduction electrons are those which have been excited to states within this band.
Conduction band edge – It is the lowest energy level of the conduction band in a solid-state material or semi-conductor.
Conduction band minimum – It is the lowest energy level located at the bottom edge of the conduction band in a semi-conductor or insulator.
Conduction band state – It is an energy level in the lowest range of vacant (or partially filled) electron orbitals in a solid material where electrons can move freely and carry an electrical current.
Conduction heat loss – It is the transfer of thermal energy through a solid material or stationary fluid from a warmer region to a cooler region because of a direct temperature difference, without any bulk movement of the medium itself.
Conduction heat transfer – It is the process by which thermal energy moves from higher-temperature regions to lower-temperature regions through direct physical contact between adjacent atoms, molecules, or free electrons within a material.
Conduction loss – In electrical and electronics engineering, conduction loss is the power loss that happens when an active semi-conductor device or a conductor is in the ‘ON’ state and carrying current. In thermal engineering, conduction loss refers to thermal energy which escapes or transfers through a solid material or barrier because of a temperature difference.
Conduction transfer function – It is a mathematical methodology used to predict transient heat conduction through multi-layer building elements like walls and roofs. It relates the heat flux at a surface (inside or outside) to current and past values of surface temperatures and heat fluxes over discrete time steps (typically 1-hour intervals).
Conduction velocity – It is the speed at which an electrical impulse, action potential, or signal propagates through a conducting medium. It is calculated as the distance travelled by the electrical signal divided by the propagation time delay (latency) between two points. Conduction velocity (CV) = distance / time delay (latency).
Conductive adhesive – It is a specialty polymer-based bonding material which provides both mechanical attachment and an electrical (or thermal) pathway between electronic components.
Conductive anodic filament (CAF) growth – It is an internal electro-chemical failure mode in printed circuit boards (PCBs) where copper-containing filaments or salts grow subsurface along the interface between glass fibre reinforcement and the epoxy resin system.
Conductive atomic force microscopy – It is a scanning probe technique which simultaneously maps a material’s surface topography and measures local electrical current at the nano-scale.
Conductive charger – It is a system which transfers electrical energy from a power source to a device or electric vehicle through a direct physical and metallic contact (using cables, plugs, or sockets) rather than wirelessly.
Conductive coating – It is a thin layer of material applied to a substrate to carry an electrical charge or dissipate static across a surface.
Conductive fibre – It is a specialized textile strand or filament engineered to carry electrical current or dissipate static charge while maintaining traditional textile properties like flexibility and low weight.
Conductive filament – It refers to a specialized thermoplastic composite. such as polylactic acid (PLA) or thermoplastic polyurethane (TPU), infused with conductive additives like carbon black, graphene, carbon nanotubes, or metal powders.
Conductive filament formation – It is frequently called conductive anodic filament (CAF) growth. It is a failure mechanism where a copper-containing conductive salt filament grows through microscopic paths along the glass-fibre / epoxy resin interface inside a printed circuit board. It is triggered by board degradation, humidity / water absorption, poor glass-to-resin silane bonding, and an electrical potential (bias voltage) between internal conductors.
Conductive gasket – It is a sealing component which bridges two surfaces to provide both a reliable environmental seal (against moisture, dust, and pressure) and continuous electrical conductivity or electro-magnetic shielding.
Conductive hydrogel – It is a three-dimensional, water-swollen polymeric network which combines the soft, flexible, and bio-compatible nature of traditional hydrogels with built-in electrical or ionic conduction pathways.
Conductive ink – It is a specialized, functional liquid or paste printed onto a surface to conduct electricity. It replaces traditional copper-etched circuit boards and wires with an additive manufacturing process.
Conductive material – It is a substance which allows the free flow of electrical charges or thermal energy with minimal resistance.
Conductive particles – These particles are microscopic or nano-scale materials, such as silver, gold, copper, carbon nano-tubes, or graphene, which transmit electrical or thermal energy when dispersed within a matrix, liquid medium, or solid composite.
Conductive passivation – It refers to a specialized surface treatment or thin-film layer which protects an underlying material from corrosion or environmental degradation while still allowing electrical current to pass through it. While traditional passivation layers (such as thick silicon di-oxide or polymer coatings) act as complete electrical insulators, a conductive passivation layer maintains a controlled path for charge or electron flow.
Conductive path – It is a continuous physical or geometric route which allows electrical current, electro-magnetic energy, or thermal energy to flow from a source to a destination.
Conductive plastic – It is a functional polymer to carry electrical current or transfer thermal energy, overcoming the natural insulating properties of standard plastics.
Conductive polymer – It is an organic macro-molecule which conducts electricity with semi-conductor-to-metallic properties, while keeping the light weight, flexibility, and processing ease of conventional plastics.
Conductive powder – It is a finely divided material, such as graphite, carbon black, copper, nickel, or silver, mixed into insulating matrices (like polymers, resins, cements, or coatings) or used in loose / pressed states to impart or control electrical and thermal conductivity.
Conductive sub-layer – It refers to a distinct thin stratum or region, either within a thermal / fluid boundary layer or a multi-layered material stack, where heat transfer or electrical / carrier conduction mainly takes place.
Conductive thermal resistance – It is a measure of how much a material or structural layer opposes the flow of heat through conduction. It is the ratio of the temperature difference across a material to the rate of heat flow (heat current) passing through it.
Conductivity – It is the property of a water sample to transmit electric current under a set of standard conditions. It is normally expressed as micro-ohms conductance. It is a measure of the ability of water to pass an electrical current. Since dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases. Conductivity is also a material property relating heat flux (heat transferred per unit area per unit time) to a temperature difference.
Conductivity contribution – It refers to the individual share or portion which a specific component, charge carrier, ion, or vibrational mode adds to the overall electrical or thermal conductivity of a system.
Conductivity distribution – It refers to the spatial variation of electrical or thermal conductivity throughout a physical body, component, or system.
Conductivity, electrical – It is the proportionality constant between current density and applied electric field. It is also a measure of the ease with which a material is capable of conducting an electric current.
Conductivity measurement – It is the quantitative assessment of how easily a material or an aqueous solution can carry an electrical current.
Conductivity ratio – It is defined as the measured conductivity of a composite material, porous medium, or mixture divided by the idealized conductivity calculated using theoretical models such as the rule of mixtures.
Conductivity sensor – It is an analytical instrument which measures an aqueous solution’s ability to conduct an electrical current, which directly correlates with the concentration of dissolved ionic species (such as salts, acids, and bases).
Conductivity tensor – It is a second-rank tensor which mathematically defines the linear relationship between a driving vector field (such as an electric field or temperature gradient) and the resulting flux response vector (such as electric current density or heat flux) in anisotropic materials. [1,
Conductivity, thermal – Thermal conductivity is a material’s intrinsic ability to conduct or transfer heat. It is quantified as the rate of heat flow through a unit area of a material per unit temperature gradient, measured in watts per meter-kelvin.
Conductometer – It is very frequently referred to as an electrical conductivity meter or EC meter. It is a precise analytical instrument designed to measure the ability of a liquid solution or material to conduct an electric current. In chemical, environmental, and process engineering, this measurement serves as a direct indicator of ionic concentration, total dissolved solids (TDS), and the overall purity of a liquid.
Conductometric detection – It is an electro-chemical analysis method which measures changes in the electrical conductivity of a solution or sample to determine the concentration of ionic analytes.
Conductometry – It is a technique used in electro-chemical analysis to measure the conductivity of an electrolyte solution, which relates the ionic concentration to the electrical conductivity of the solution. This technique utilizes two electrodes immersed in the solution, with conductivity determined through the application of Ohm’s law.
Conduct of operations – Ir is frequently referred to as operational discipline. It is the deliberate, structured execution of daily work, management tasks, and safety procedures to ensure consistency, minimize human error, and reduce operational risk.
Conductor – It is an object or type of material which allows the flow of charge (electric current) in one or more directions. Materials made of metal are common electrical conductors. The flow of negatively charged electrons generates electric current, positively charged holes, and positive or negative ions in some cases.
Conductor diameter – It is the physical size (width) of the central conductive element, such as a copper or aluminum core, in a wire or cable, strictly excluding any outer insulation or protective layers.
Conductor line – It is a physical wire, cable, or bundle of wires suspended or laid out to transmit electrical energy from a source (such as a power plant) to a load or substation with minimal resistance and power loss.
Conductor loss – It is the power dissipated as heat in a metal conductor when electrical current flows through it, caused by the finite electrical resistance of the material rather than a perfect loss-free state.
Conductor pipe – It is the first, largest-diameter, and shortest string of steel casing installed at the very beginning of drilling an oil, gas, or water well.
Conductor sag – It is the vertical distance between the support points (such as utility poles or towers) and the lowest point of a suspended overhead wire. : It is the natural, intentional downward curve (catenary or parabola) a conductor forms because of the gravity.
Conductor screening – Cables rated for 6.35 kilo-volts / 11 kilo-volts are provided with conductor screening over the conductor by applying non-metallic semi-conducting tape or by extrusion of semi-conducting compound or a combination of the both.
Conductor tension – It is the longitudinal pulling force exerted along an overhead power line or cable as it spans between support structures (such as towers or utility poles).
Conduit – A conduit is a small tunnel, pipe, or channel through which water or electrical wires go. Conduit is used for protecting and routing electrical wiring in a building or structure.
Conduit, rigid – It is the conduit having dimensions of nominal size 40 pipe in standardized length with threaded ends.
Conduit pipe – It is welded or seamless pipe intended especially for fabrication into rigid conduit, a product used for the protection of electrical wiring systems. Conduit pipe is not subjected to hydrostatic testing unless so specified. It can be black or galvanized, as specified. It is furnished in standard weight pipe sizes from 6 mm to 150 mm in lengths of around 3 m to 6 m, with plain ends or threaded ends, as specified.
Cone – It is the conical part of an oxy-fuel gas flame next to the orifice of the tip. In refractory, cone is a hollow refractory shape which is used in bottom pouring, through which the liquid steel passes from the runner brick into the ingot mould. When made in one piece with the runner brick, it is known as riser brick or an end runner.
Cone angle – It is the angle which the cutter axis makes with the direction along which the blades are moved for adjustment, as in adjustable-blade reamers where the base of the blade slides on a conical surface.
Cone area – It typically refers to one of three specific measurements depending on the field namely the lateral surface area, the total surface area, or the cross-sectional / projected area of a conical component. Lateral surface area measures only the sloped, curved surface of the cone (excluding the flat circular base). It is highly relevant in manufacturing, sheet metal fabrication, and heat transfer calculations. Total surface area (TSA) includes both the sloped lateral surface and the flat circular base. It is used to determine coating materials, painting costs, and total skin friction in fluid dynamics. In case of speaker acoustic engineering effective cone area is the measurement of the moving surface of a loudspeaker cone. It includes the hard cone plus a portion of the flexible suspension (surround). In cse of aerospace and fluid dynamics, engineers look at the projected frontal area (a 2D triangle or circle silhouette) to calculate the aerodynamic drag coefficient of nose cones on rockets and aircraft. In cone penetration testing (CPT), the cone area” refers specifically to the cross-sectional area of the tip of a cylindrical penetrometer (typically 10 square centimeter or 15 square centimeter), used to measure soil resistance.
Cone bit – It is frequently called a roller cone bit or tricone bit. It is a specialized rotary drill bit used in mining, construction, water well drilling, and oil and gas exploration to fracture and crush hard or abrasive rock formations. It is a rock-breaking tool featuring one, two, or three independently spinning conical cutters (cones) mounted on bearings at the base of the bit body.
Cone bolt – It is a specialized yield support rock bolt used in mining and geotechnical engineering to absorb massive quantities of kinetic energy during rock bursts and heavy rock deformation. It consists of a smooth steel bar with a conical (wedge-shaped) flaring at the distal end.
Cone calorimeter – It is a bench-scale instrument used to evaluate the fire behaviour and combustion properties of small material samples. It is widely regarded as the most important laboratory tool in fire safety engineering.
Cone classifier – It is simply a cone / conical vessel installed point down. It consists of a discharge launder around the top. The feed is introduced in the form of a suspension through a feed inlet provided at the centre at the top. The coarse particles get collected at the point of the cone while the fine fraction along with the liquid is removed from launder as overflow. Cone classifiers are normally used in ore dressing plants.
Cone crusher – Cone crusher is consisting of a crushing chamber, a crushing cone and an operating mechanism. The cone is built in to a vertical shaft, which is supported from the top with a bowl-shaped bearing and from the other end to an eccentric operating mechanism.
Coned-out coil – It is lateral stacking, mainly in one direction, of wraps in a coil so that the edges of the coil are conical rather than flat. Improper alignment of rolls over which the metal passes before rewinding is a typical cause.
Cone of depression – It is the depression, roughly conical in shape, produced in an aquifer by pumping in a well. The radius of water affected around the well is called the area of influence. This area of influence varies, depending upon several factors such as the characteristics of the rock or soil formation (material) the water must travel through to get to the well.
Cone penetration test – It is an in-situ geotechnical investigation method where a specialized, instrumented steel probe is hydraulically pushed vertically into the ground at a constant rate of 20 millimeters per second (15 millimeters per second to 25 c millimeters per second) to evaluate soil stratigraphy and engineering properties.
Cone penetration testing – It is an in-situ (on-site) geotechnical investigation method where a specialized steel probe is hydraulically pushed into the ground at a constant rate to continuously measure soil resistance and properties.
Cone penetrometer – It is a slender, instrumented tool with a cone-shaped tip which engineers push into the ground to measure soil strength and map underground layers. This process is known as the cone penetration test (CPT).
Cone resistance – It is the resistance measured at the cone tip during cone penetration testing (CPT), which varies by soil type, with values in clays typically being low (up to 5 mega-pascals) and those in sands potentially exceeding 40 mega-pascals.
Cone resistance value – It is a measure of the yield stress of a grease, obtained by static indentation with a cone. It is to be noted that the equilibrium depth of penetration is measured, not the penetration in a given time, which is the penetration value.
Cone sample scanning – In this method of evaluating steel cleanliness, a cone-shaped volume of continuous cast steel is scanned with a spiraling detector, such as a solid ultrasonic system, which automatically detects surface inclusions at every location in the area of the sample, including from surface to centre-line.
Cone shell method – It is the simplest of the stacking methods. In the cone shell method, the pile is formed by depositing material in a single cone from a fixed position. When this conical pile is full, the stacker moves to a new position and a new cone is formed against the shell of the first one. This process continues in the longitudinal direction of the storage pile until the stockpile is complete.
Cone spinning – It typically refers to metal spinning to form conical parts, or it can describe specialized rotating cone equipment like a spinning cone used for fluid processing.
Cone type separator – It is very frequently referred to as a cyclone separator or hydrocyclone depending on the medium. It is a static separation device which utilizes centrifugal force and gravity within a narrowing conical chamber to separate multi-phase mixtures (such as solids from gases, solids from liquids, or fluids of different densities) without the use of moving parts.
Cone volume – The volume of a cone is the total three-dimensional space enclosed within its surface, equal to one-third the volume of a cylinder with the same base radius and vertical height.
Confidence – Confidence in the validity of a finding, based on the type, quantity, quality, and consistency of evidence and on the degree of agreement. Confidence is expressed qualitatively.
Confidence interval – It is an interval of numbers which people are very confident contains the true value of a population parameter. A confidence interval gives an estimated range of values which is likely to include an unknown population parameter. The width of the confidence interval gives an idea of how uncertain people are about the unknown parameter. A very wide interval can indicate that more data needs to be collected before an effective analysis can be undertaken. Confidence interval is that range of values, calculated from estimates of the mean and standard deviation, which is expected to include the population mean with a stated level of confidence. Confidence intervals in the same context also can be calculated for standard deviations, lines, slopes, and points.
Confidence level – It is the pre-chosen statistical probability which a calculated interval contains the true unknown population parameter (such as material strength, component lifespan, or operational load) over repeated tests or manufacturing runs.
Confidence limits – These are the upper and lower boundaries of a confidence interval. They define the exact numerical range within which a true population parameter (such as a mean strength, tolerance, or stress value) is expected to lie with a specified degree of probability.
Confidential business information – It refers to non-public technical, design, and operational data which provides an organization with a competitive advantage, and whose unauthorized disclosure can cause commercial harm or economic loss.
Confidentiality – It is the professional and ethical duty to protect sensitive, non-public information, such as proprietary designs, trade secrets, and client data, from unauthorized access or disclosure.
Confidentiality, integrity, and availability – These are known as the CIA triad. These are the three core principles used to design secure systems.
Configurable – It means designing a system, device, or software so its features can be changed or adjusted using built-in settings without rewriting its core code.
Configuration – Configuration of a product involves shaping its functions and characteristics to make it suitable for customer use.
Configurational partition function – It is the part of a system’s total classical partition function which depends strictly on the spatial positions and interactions of its particles, excluding their momenta. It accounts for how particles are arranged in coordinate space weighted by their potential energy, making it 0mportant for dense fluids, solids, and liquids where interparticle forces are strong.
Configuration-as-code – It is an innovative approach to managing and provisioning computing resources. It refers to the practice of handling changes, deployments and updates to software and systems via code rather than manual processes. Configuration-as-code (CaC) allows for a version-controlled, reproducible and automated method of managing environments, leading to more consistent and reliable systems. The essence of configuration-as-code is to treat system configurations the same way that software code is treated. This means that configurations are written in a code format, stored in a version control system and applied through automated processes. This approach brings several benefits, including consistency, repeatability and the ability to test changes before applying them to live environments.
Configuration baseline – It is a formally reviewed, approved, and immutable snapshot of a system’s specifications, requirements, or physical design at a specific point in its lifecycle. It serves as a fixed reference point to manage, measure, and audit future changes.
Configuration control – It is the systematic process of identifying, evaluating, approving, and tracking all changes made to a system’s physical, functional, and documented characteristics throughout its life-cycle.
Configuration data – It is the set of settings, parameters, and operational details which control how a software application, operating system, or hardware device behaves. Unlike application code (which defines what a programme does), configuration data defines how it runs in a specific environment without requiring you to rewrite or recompile the source code.
Configuration design – It is the stage after conceptual design in the engineering design process in which the features of a part and their arrangement and connectivity are determined. Qualitative reasoning based on fundamental principles is used to make decisions between alternatives. A sketch of the part and preliminary decisions on material selection and manufacturing methods are made in this stage. Final dimensions and tolerances are not determined in this stage. It is also known as embodiment design.
Configuration file – It is a plain-text or structured file which stores settings, preferences, and operational parameters for software applications, operating systems, or hardware devices.
Configuration guidelines – These configurations refer to the standardized technical rules, design rules, and process frameworks used to structure the composition, processing path, and geometry of metals and alloys to achieve specific mechanical or chemical properties.
Configuration identification – It is the foundational process in configuration management which involves selecting system components, defining their physical and functional attributes, and assigning unique names, numbers, or labels to track them across their life-cycle.
Configuration item – It is a self-contained, identifiable component of a system (such as hardware, software, a file, a document, or a model) designated for formal configuration management and change control.
Configuration management – It is a systems engineering and governance process which establishes and maintains consistency of a product’s or system’s functional, physical, and performance attributes with its requirements, design, and operational information throughout its entire lifecycle.
Configuration management process – It is a systematic approach to planning, identifying, controlling, and tracking a product’s configuration from its inception to its end-of-life, emphasizing efficiency and accuracy while minimizing costs. It involves a blend of elements such as product and document release, bill of materials, requests, and changes, with a focus on training and well-documented standards.
Configuration mode – It is a dedicated state or administrative context where parameters, options, and rules of a system, device, or software are defined, initialized, or modified without executing live operational tasks.
Configuration option – It is the structured process of identifying, specifying, modelling, and managing the parameters, choices, and rules which determine how a system, product, software, or piece of hardware can be configured.
Configuration policy – It is the practice of establishing, documenting, and enforcing formal rules which govern how hardware, software, network elements, and system baselines are set up, modified, and tracked across their life-cycle.
Configuration space – It is the space of all configurations of a rigid body, representing the position and orientation of the body in a given work-space. Each configuration is a point in this space, which is used for motion planning by finding paths that avoid collisions with obstacles.
Configuration strategy – It is a high-level plan or set of guidelines used to direct how a system, network, or product adopts, manages, and transitions through specific technical configurations in response to changing operational contexts or high-level requirements.
Configuration unit – It is a distinct element, software component, or hardware part which holds specific settings, parameters, or deployment rules applied to a broader system or unit. It represents set-up data, operational parameters, or structural rules (such as server data sources, user groups, or hardware component arrangements) assigned to a target system.
Configuration wizard – It is a graphical tool which guides users through a series of sequential steps to set up, initialize, or customize a complex system, device, or software component.
Configuration word – It is a special set of bits in programme memory which lets users set hardware options and operating modes before or during program download.
Confined carriers – These carriers refer to charge carriers which are trapped within potential wells of small dimensions, resulting in quantum confinement that alters their energy band structure and density of states distribution. These carriers can show quasi-2D, 1D, or zero-dimensional characteristics depending on the geometry of the confinement.
Confined channel – It is a waterway, conduit, or flow path where the fluid flow is physically constrained on its sides and bottom by fixed, rigid, or well-defined boundaries. This restriction directly impacts the fluid’s velocity, depth, and hydraulic behaviour, preventing it from naturally spreading out or changing its path.
Confined compressive strength – It is the maximum axial compressive stress a material or structural element can withstand when subjected to a combination of primary axial load and lateral (confining) pressure. Unlike unconfined compressive strength, where a sample is squeezed axially with zero lateral support, confined compression restrains the material from expanding outward sideways (lateral or radial strain).
Confined concrete – It is concrete which is laterally supported or encased to prevent outward expansion, which considerably increases its compressive strength, strain capacity, and ductility.
Confined geometry – It refers to any physical system, fluid flow, or material structure constrained within limited spatial dimensions or boundary walls.
Confined jet – It is a fluid jet which issues from a nozzle directly into an enclosed space, such as a duct, pipe, combustion chamber, or reactor, rather than expanding into an infinite, open medium.
Confined space – It is an area which is not designed for continuous human occupancy and has limited opening for entry, exit, and ventilation.
Confined web – It refers to a relatively thin, plate-like section of a forging that is predominantly or entirely obstructed by surrounding ribs, bosses, or other raised projections.
Confinement – It is the process of preventing the release of radioactive substances to the environment during operation or following an accident.
Confinement effect – It refers to the physical, chemical, or quantum restriction of movement, particle size, or spatial dimensions that fundamentally alters the behaviour, energy states, or mechanical strength of a material.
Confinement number – It is a dimensionless number used in fluid mechanics and thermal-hydraulics (such as micro-channel flow boiling and two-phase closed thermosyphons) to measure the extent of flow confinement inside a channel or tube.
Confinement tube – It is an outer structural casing, normally made of steel, fibre-reinforced polymer (FRP), or PVC (polyvinyl chloride), which encases a core material (like concrete or fluid) to provide lateral pressure, restrict outward expansion, and considerably increase load-bearing capacity and ductility.
Confining layer – It is a geologic formation with very low permeability which considerably restricts or blocks the vertical movement of groundwater between aquifers.
Confining pressure – It is the uniform all-around lateral and vertical pressure applied to the external surface of a material or rock mass. It is an isotropic stress state (frequently denoted as sigma3 in tri-axial testing) where equal compressive forces squeeze a sample from all sides. In the field, it corresponds to the lithostatic or overburden pressure exerted by the weight of surrounding soil and rock layers.
Confining stress – It is frequently denoted as sigma3. It is the uniform, all-around compressive pressure applied perpendicularly to the lateral sides of a body, material, or soil / rock mass.
Confining surface – It refers to the boundary, material layer, or geometric restriction used to isolate, stabilize, or modify the behaviour of a core material under load, stress, or chemical reactions.
Confirmation – It is the systematic act of providing objective evidence and testing data to prove that a design, hypothesis, or process meets specified requirements and performs correctly.
Conflict – It is a dynamic state of disagreement or incompatible goals, ideas, or interests which occurs within technical teams, project environments, or professional ethics.
Conflict graph – It is a representation of logical relations between binary variables, used to model interference constraints in resource allocation problems. It helps in solving issues such as frequency allocation by showing how different variables or nodes interact with each other.
Conflict of interest – It occurs when an engineer’s personal, financial, or organizational interests interfere, or appear to interfere, with their professional objectivity and duty to the public, client, or employer.
Conflict resolution – It is the structured process of identifying, managing, and settling technical, structural, or inter-personal disagreements among team members to reach a constructive, evidence-based solution. Unlike general work-place disputes, engineering conflict resolution frequently balances objective technical trade-offs (such as architecture choices or design patterns) with human and operational factors.
Confocal imaging – It is an optical technique which uses single-point laser illumination and a spatial pinhole aperture to reject out-of-focus background light, producing high-contrast 2D and 3D images.
Confocal laser scanning microscope – It is a microscope which focuses on a single focal plane while excluding unfocused planes, allowing for the visualization of non-blurry, true images. It is capable of reconstructing 3D images by compiling multiple single focal planes and can analyze and export data using appropriate software.
Confocal microscope – It is an optical imaging instrument which confines illumination and detection to a single diffraction-limited spot using pinhole apertures, blocking out-of-focus background light to build high-contrast 2D and 3D images.
Confocal microscopy – It is an optical imaging technique which improves optical resolution and contrast by focusing light on a single point within a defined focal plane, hence minimizing image distortion and allowing for the reconstruction of three-dimensional images from two-dimensional scans.
Conformability – In tribology, it is that quality of a plain bearing material which allows it to adjust itself to shaft deflections and minor misalignments by deformation or by wearing away of bearing material without producing operating difficulties.
Conformal antenna – It is an antenna array mounted on or embedded inside a curved or non-planar surface whose shape is dictated by non-electromagnetic requirements, such as aero-dynamic, hydro-dynamic, or aesthetic constraints, rather than pure radio wave performance.
Conformal coating – It is a coating which covers and exactly fits the shape of the coated object.
Conformal contact – It refers to a type of surface interaction where two mating parts have closely matched or complementary geometric profiles (such as a convex surface fitting snugly inside a concave surface).
Conformal cooling channels – These are specialized cooling passageways inside a mould (such as for plastic injection moulding or metal die casting) which follow or ‘conform’ to the exact 3D contours and geometry of the mould cavity. Unlike traditional straight-drilled cooling lines which leave uneven gaps and hot spots, conformal channels maintain a uniform, equidistant distance from the moulding surface.
Conformality – It is the degree to which a product, process, or material fulfills predetermined engineering specifications, tolerances, and regulatory standards. It is also the quality of a thin film or coating which uniformly covers all exposed surfaces of a complex 3-dimensional structure with equal thickness, regardless of topography. Conformality is also a property of a geometric transformation or mapping [w = f(z)] which preserves local angles in both magnitude and orientation at every point where the derivative is non-zero (f'(z) is not 0). This property is used in fluid dynamics, heat transfer, and electrostatic field mapping to transform complex physical boundaries into simpler geometries.
Conformal mapping – It is a two-dimensional mathematical transformation which preserves local angles and shapes while changing the underlying geometry. It is used to take a complex or awkward physical boundary and map it onto a simple, well-understood geometry (such as a circle). Since governing physical laws, like Laplace’s equation for fluid flow, electrostatics, and heat transfer, remain invariant (unchanged) under this transformation, engineers can solve the problem in the simple domain and map the solution back to the real-world geometry.
Conformal mapping function – It is a complex transformation which locally preserves the angles between intersecting curves and the shapes of tiny figures, even though it may change their overall size or position.
Conformal surfaces – These are the surfaces whose centres of curvature are on the same side of the interface. In wear testing, it refers to the case where the curvature of both samples matches such that the nominal contact area during the testing remains approximately constant.
Conformal transformation – It is a geometric function which preserves local angles between intersecting curves in both magnitude and orientation, even though it may alter lengths and areas. It is a transformation of a Riemannian manifold which scales the metric by a positive function, resulting in a new metric which preserves angles but not necessarily distances. Two Riemannian manifolds are said to be conformally related if they are connected by such a transformation.
Conformance – It is the degree to which a product, service, or process meets established design specifications, standards, and requirements.
Conformance testing – It is the process of checking if a product, system, or material meets the exact rules of an official standard, technical specification, or contract. It is also known as type testing or compliance testing.
Conformers – It is short for conformational isomers. Conformers are the different spatial arrangements of atoms in a molecule that occur through the free rotation around single (σ) covalent bonds. Since single bonds allow continuous twisting without breaking chemical bonds, a single molecule can take an infinite number of temporary 3D shapes. Each specific shape is a conformation, and the relatively stable, low-energy arrangements found at local energy minima are the conformers.
Conform extrusion – It is also known as continuous rotary extrusion (CRE). It is a specialized metal forming process in metallurgy where frictional forces between a moving tool and a feed-stock are used to continuously push, heat, and deform metal through a die. Unlike traditional batch extrusion which relies on a hydraulic ram to push finite billets, the Conform process provides uninterrupted, continuous production of infinite lengths of metal profiles, wires, or tubes directly from raw materials like coiled rod or particulate powder.
Conforming element – It is also known as a compatible element. It is a finite element whose approximation functions satisfy the continuity requirements across element boundaries. Mathematically, an element is conforming if its finite element function space is a direct subspace of the exact solution space (Vh subset V) needed by the variational or ‘weak’ form of the governing partial differential equation.
Conformity – It is the fulfillment of specified requirements.
Conformity assessment – It is the formal, evidence-driven process used to prove that a product, system, process, or material meets specified technical standards and safety regulations. It demonstrates that specified requirements are fulfilled.
Conform process – It is a continuous rotary extrusion (CRE) technique which uses frictional forces to feed, heat, and deform non-ferrous metals into precise shapes of infinite length. It eliminates the need for individual billets and separate pre-heating furnaces, combining multiple manufacturing steps into a single, automated, and energy-efficient operation.
Confusion matrix – It is a table used to visualize the performance of a classifier, with rows and columns representing each class, where each entry indicates the number of cases where a sample has been classified as a particular label. It can contain raw counts or normalized values, and a perfect classifier shows all non-zero entries along the diagonal.
Congestion component – In power systems engineering, the congestion component is part of the locational marginal price (LMP) of electricity. It acts as a dynamic financial toll when a transmission line reaches its capacity or becomes overloaded. In transport layer protocols like compound transmission control protocol, the congestion component represents the portion of the congestion window size which reacts specifically to loss-based congestion signals using standard transmission control protocol (TCP) Reno rules. In VLSI (very large-scale integration) / FPGA (field programmable gate array) hardware design, a congestion component or area in chip design marks a localized region where interconnect resource or logic block utilization approaches or exceeds 100 %. In transportation, the congestion component is a quantitative share of traffic delay or speed reduction (measured against free-flow conditions) attributed to specific sources like bottlenecks, incidents, weather, or excess demand.
Congestion control – It is a set of techniques and algorithms which regulates the flow of data entering a network to prevent overload, high delays, and congestive collapse when traffic demand exceeds available capacity.
Conglomerate – It is a sedimentary rock consisting of rounded, water-worn pebbles or boulders cemented into a solid mass.
Congruence properties – The property of congruence means two or more geometric figures have the exact same shape and size. The three properties of congruence are the reflexive property, the symmetric property, and the transitive property. Reflexive property says that any angle A is congruent to angle A. Symmetric property says that if angle A is congruent to angle B, then angle B is congruent to angle A. Transitive property says that if angle A is congruent to angle B, and angle B is congruent to angle C, then angle A is congruent to angle C.
Congruency – It means that two or more physical parts, geometric models, or signals match each other in shape, size, or structural fit.
Congruent melting – It is an isothermal or isobaric melting in which both the solid and liquid phases have the same composition throughout the transformation.
Congruent point – The congruent point on a phase diagram is where different phases of same composition are in equilibrium.
Congruent transformation – It is an isothermal or isobaric phase change in metals in which both of the phases concerned have the same composition throughout the process.
Conical cup wrinkling test – It is frequently based on Fukui’s conical cup test. It is a sheet metal forming procedure used to evaluate the formability, drawing behaviour, and susceptibility to buckling or wrinkling of metallic sheets.
Conical-entry die – It is a precision manufacturing tool featuring a tapered, funnel-shaped internal opening used to gradually deform and reduce the cross-sectional area of metal as it is forced through the die. Rather than hitting a sharp, flat wall, the metal enters a sloped reduction or approach cone. This geometry is very frequently used in bulk deformation processes like wire drawing, rod drawing, tube nosing, and metal extrusion.
Conical flow – It refers to a fluid flow field where all flow properties, such as velocity, pressure, temperature, and density, remain constant along straight rays (lines) emanating from a single common point (the vertex or origin) in physical space.
Conical gear – It is normally known as a bevel gear. It is a cone-shaped machine element with teeth cut onto a truncated conical surface (frustum). It is mainly used to transmit rotational power and change the direction, speed, or torque between intersecting or angular shafts, typically at a 90-degree angle.
Conical-H die – It refers to a specifically designed extrusion or drawing tool featuring a conical entry zone which transitions into an H-shaped exit profile. It is used to transform standard cylindrical metal billets into complex structural H-beams or H-sections through solid-state plastic deformation.
Conical shells – These are truncated conical structures characterized by a vertex angle, where their behaviour can be described using specific equations which relate to longitudinal and circumferential coordinates. These structures can transition to flat circular plates or cylindrical shells under certain conditions.
Conical tube – It is a tubular structure or channel whose cross-sectional area changes gradually along its length, forming a cone-like taper. In fluid and heat transfer, conical tube is a conduit where cross-sectional area decreases or increases progressively from inlet to outlet. In acoustics and wave-guides, it is a conical acoustic tube acts as a one-dimensional wave-guide which propagates spherical pressure waves rather than plane waves, governed by modifications to Webster’s horn equation. In structural and crash engineering, truncated conical shells and corrugated conical tubes are used in offshore structures, vehicles, and towers to handle axial loads, optimize buckling resistance, and absorb impact or crush energy. In laboratory and process equipment, a conical centrifuge tube (frequently called a Falcon tube) features a cylindrical body with a tapered, cone-shaped bottom designed to withstand high centrifugal G-forces, concentrating dense suspended particles into a tight pellet at the tip.
Conic constant – It is also called the Schwarzschild constant, it is a parameter which describes the shape of a conic section rotated around its main axis (such as an ellipsoid, paraboloid, or hyperboloid).
Conic curve – It is a planar algebraic curve of degree 2, represented by an implicit equation, and is the locus of points such that the distance from a fixed point (focus) is proportional to the distance from a fixed line (directrix). Depending on the eccentricity, conic curves can take the shape of ellipses, parabolas, or hyperbolas.
Coning and quartering method – It is a method for the reduction in size of a granular or powdered sample by forming a conical heap which is spread out into a circular, flat cake. The cake is divided radially into quarters and two opposite quarters are combined. The other two quarters are discarded. The process is repeated as many times as necessary to obtain the quantity desired for some final use (e.g. as the laboratory sample or as the test sample). If the process is performed only once, coning and quartering is no more efficient than taking alternate portions and discarding the others.
Conjugate beam method – It is an analytical technique used to determine the slope and deflection of a beam. It uses an imaginary (conjugate) beam which has the exact same span length as the real beam. The load applied to this conjugate beam is the M/EI diagram, where ‘M’ is the bending moment, ‘E’ is the modulus of elasticity, ‘I’ is the moment of inertia, and ‘EI’ is the flexural rigidity.
Conjugated micro-porous polymers – These are defined as 3D network structures composed of rigid blocks linked by pi-conjugated bonds, featuring tunable microporosity which can be achieved through different building blocks and reaction types.
Conjugated, phase – Phase conjugated refers to a wave which propagates in the reverse direction of an incident wave, whose complex amplitude is the complex conjugate of the incident wave, allowing the wave-fronts to coincide. This phenomenon is frequently realized using a phase-conjugate mirror, which is produced through processes such as degenerate four-wave mixing.
Conjugate gradient (CG) method – It is an iterative numerical algorithm used in engineering and applied mathematics to solve large-scale systems of linear equations (Ax = b) or to minimize quadratic optimization problems where the matrix ‘A’ is symmetric and positive-definite.
Conjugate phases – In microstructural analysis, these are those states of matter of unique composition which coexist at equilibrium at a single point in temperature and pressure. For example, the two coexisting phases of a two-phase equilibrium.
Conjugate planes – These are the two planes of an optical system such that one is the image of the other.
Conjugate points – These are points along a minimal geodesic where there exists a non-trivial Jacobi field which vanishes at both points, indicating a specific geometric relationship between them.
Conjugate prior – In Bayesian statistics, it is a prior probability distribution which, when combined with a specific likelihood function, results in a posterior distribution belonging to the same probability distribution family.
Conjugate variables – These are pairs of physical or mathematical quantities which are linked together, where the product of the two variables yields an energy transfer or forms a Fourier transform dual.
Connate water saturation – It is the fraction of total pore volume in a reservoir rock which is occupied by immobile water held tightly to the rock grain surfaces by capillary and wettability forces.
Connected component – It is a maximal sub-network, sub-set of nodes, or cluster of pixels where every element is linked to every other element by a path, and no additional elements can be added from outside without breaking this connection.
Connected operations – It is an operational model which links physical assets, machines, sensors, frontline workers, and enterprise software into a unified, real-time digital network. Connected operation is also the mode of micro-grid functioning where it follows the distribution rules of the main power system, allowing it to draw power from or supply power to the main grid while acting as a controllable load or source.
Connected product – It is the multi-disciplinary practice of designing, developing, testing, and managing physical hardware which integrates sensors, embedded software, network connectivity, and cloud or edge systems to generate and share operational data.
Connected system – It is a collection of sensors, hardware, devices, software, and machines linked through digital or physical networks to share data, perform analysis, and enable remote or automated control.
Connecting beam – It is also known as a tie beam, coupling beam, or strap beam depending on its specific application. It is a horizontal structural element used to link two or more structural components together. Its main purpose is to transfer loads, stabilize the structure, and prevent relative movement between the connected elements.
Connecting nodes – It refers to the establishment of paths between nodes in a network, allowing traversal through edges, which can determine the graph property of connectedness. Two nodes are connected if there is a path between them, and a graph is considered connected if all pairs of nodes are connected by such paths.
Connecting path – It is the continuous sequence of structural elements, connections, and interfaces (such as slabs, beams, columns, shear walls, and foundations) which safely transfers external forces—like gravity, wind, or seismic loads, down into the ground. It is also the physical route or channel, including power lines, internal wiring, printed circuit board (PCB) tracks, or data transmission lines, through which signals travel or unwanted interference (coupling) occurs.
Connecting rod – It is the mechanical linkage between the piston and crankshaft in an engine, needing high strength, low inertial mass, and uniformity with other connecting rods. It typically couples to the crank-shaft through solid journal bearing half shells and to the piston through a hardened steel gudgeon pin.
Connecting shaft – It is also called an intermediate shaft. It is a mechanical component used to transmit torque and rotational motion between two spatially separated shafts or rotating sub-assemblies in a power-train.
Connection design – It is the process of engineering the joints, such as beam-to-column, column-to-base, or truss nodes, which hold individual structural members together to function as a single, cohesive unit. Main types of connections are bolted connections, welded connections, and hybrid connections. Connections are also classification by moment behaviour. As per this classification, connections are simple shear (pin) connections, fully restrained (moment) connections, and partially restrained (PR) connections.
Connection diagram – It is also known as wiring diagram. It depicts the general physical arrangement of electrical connections and wires between circuit elements in an installation or assembly. It shows internal connections, but may include external connections which have one termination inside and one outside the assembly. It contains the details necessary to make or trace connections involved. It is prepared to show the connection of wires and circuit elements at any level of assembly or installation. It includes (i) physical relationship of circuit elements and their connections, (ii) items identified by reference designations, (iii) clearly identified terminal arrangements, (iv) wires numbered for reference, and (v) wire and termination descriptions.
Connectionist models – These are artificial neural systems which mimic the processing of the human nervous system, normally used in artificial intelligence for tasks such as classification and pattern recognition. These models, including artificial neural networks and convolutional neural networks, are integral to computational intelligence and are particularly effective for function mapping and approximation problems.
Connectivity matrix – It is also known as an adjacency matrix. It is a square grid which mathematically represents the connections between nodes or elements in a network.
Connectivity service network – It is a erm for the core set of network functions which delivers internet protocol (IP) connectivity, mobility management, and core services to user terminals or access networks.
Connectivity table – It is normally used in finite element analysis (FEA), structural engineering, and network modeling. It is a data structure which defines how individual discrete elements or components are linked together by referencing their shared nodes or points. In methods like truss or frame analysis, a connectivity table maps each structural element (such as a beam or truss member) to the specific node numbers it connects. This allows software or engineers to assemble the global stiffness matrix by knowing which local degrees of freedom share physical space. In network and systems engineering, it defines topological relationships, such as which devices, ports, or network segments join together in a database (e.g., mapping edges to junctions or source-destination endpoints).
Connector shell – It is the outer casing or housing of an electrical, electronic, or optical connector. It encloses and protects internal components like the contacts and the insert.
Connor gate – It is also known as a Connor runner or lip feeder It is a specific type of runner / gating system where the feed block overlaps the casting by 1/16 millimeters to assist directional solidification and smooth metal flow.
Conoco Phillips E-gas gasifier – The Conoco Philips E-gas is an entrained flow gasifier. It is a two-stage gasifier with 80 % of feed to first stage (lower). The gasifier is coal-water slurry fed, oxygen-blown, refractory-lined gasifier with continuous slag removal system and dry particulate removal. The E-Gas process is good for a wide range of coals.
Conquer approach – The divide and conquer approach is defined as a problem-solving method which involves breaking a larger problem into smaller, similar sub-problems, solving each sub-problem iteratively, and then combining the solutions to form the solution to the original problem.
Conrod – It is also called the connecting rod. It is a mechanical component in an engine which links the piston to the crank-shaft.
Consecutive cycle – It normally refers to a repeating sequence of processes, states, or operational phases which occur one after another in a direct, uninterrupted series.
Consecutive packet – It refers to individual data units or network packets transmitted, forwarded, or received immediately in sequence one after another along a communication path.
Consecutive samples – These samples refer to a series of measurements taken at regular intervals in time, where each sample is got following another in a defined sequence.
Consecutive sampling – It is a non-probability sampling method where every eligible subject, measurement, or data packet meeting pre-defined criteria is collected sequentially in order of appearance or occurrence until the target sample size is reached.
Consensus – It takes place when a group of individuals in a decision-making process work towards general agreement by all involved.
Consensus audit – It is a specialized evaluation used to verify the security, correctness, and fault tolerance of distributed consensus protocols, such as those used in blockchain or decentralized systems.
Consensus model – It is a systematic framework or algorithm used by multiple independent entities (such as computers in a network or agents in a control system) to reach a unified agreement on a single data value, system state, or collective decision.
Consensus standard – It is a voluntary technical guideline or specification developed through an open, balanced, and collaborative agreement among diverse industry stakeholders, experts, and the public.
Consequence – It is the outcome, impact, or severity of an event, such as a system failure, design flaw, or hazard, measured by how it affects people, property, operations, and the environment.
Consequence analysis – It is the process of evaluating and quantifying the physical outcomes, severity, and potential impact of a hazardous event or system failure (such as a chemical leak, fire, explosion, or structural collapse). Unlike frequency analysis, which asks ‘how frequently does this happen?’, consequence analysis strictly answers: ‘how severe it is going to be if it happens?’.
Consequence category – It is a systematic classification system used in risk assessment to rank the severity of potential outcomes if a system, structure, or process fails. Consequence categories typically evaluate multiple domains simultaneously rather than looking at physical damage alone.
Consequence class – It is a classification system used to group structures based on the potential severity of failure. It measures the risks associated with the collapse or structural failure of a building or facility, accounting for potential loss of life, economic damage, social disruption, and environmental impact. Consequence classes dictate the target structural reliability, partial safety factors for ultimate limit states (ULS), and design supervision levels.
Consequence modelling – It is the mathematical simulation and analytical process used to predict the physical effects, such as thermal radiation, blast overpressure, and toxic gas dispersion, resulting from an accidental loss of containment or process failure. It answers a fundamental question in process safety ‘if something goes wrong, how bad can it be?’.
Conservation – It consists of planning, management, and implementation of an activity with the objective of protecting the essential physical, chemical, and biological characteristics of the environment against degradation. It is also the process of managing the resources through different activities such as reuse, recycling, reduction in consumption, and improvement in yield etc.
Conservation equations – These equations are defined as mathematical expressions which describe the conservation of mass, momentum, and energy within a system, incorporating variables such as density, velocity, pressure, and temperature.
Conservation, integral – Integral conservation refers to the maintenance of key quantities such as mass, energy, and angular momentum within a numerical model, which can be achieved through the application of accurate numerical methods and special measures to ensure conservation properties are upheld.
Conservation law – It is a fundamental principle stating that specific physical properties (such as mass, energy, and momentum) cannot be created or destroyed within a system, though they can change form or transfer across system boundaries. Engineers use these balance principles, expressed mathematically as algebraic, differential, or integral equations, to model, analyze, and design physical and mechanical systems.
Conservation law of energy – The law of conservation of energy states that energy cannot be created or destroyed. It can only change from one form to another within a system. In an isolated or closed system, the total quantity of energy remains constant. This law forms the basis of energy-budget analyses for devices, machines, and control volumes.
Conservation of a (measurement) standard – It is a set of operations, necessary to preserve the metrological characteristics of a measurement standard within appropriate limits. The operations normally include periodic calibration, storage under suitable conditions, and care in use.
Conservation of buildings – It is the actions taken to prevent deterioration and prolong the life-span of structures of cultural value, while dynamically managing changes to safeguard their character and heritage values. It encompasses practices which balance maintaining authenticity with contemporary requirements, ensuring the building’s significance is preserved for community use.
Conservation of energy – It is the principle stating that the total quantity of energy in an isolated system remains constant over time, meaning energy can neither be created nor destroyed but can only be transformed from one form to another.
Conservation of energy principle – It states that the total energy of an isolated system remains constant over time, Energy cannot be created or destroyed, only transformed or transferred from one form to another (such as kinetic, potential, thermal, chemical, or electrical).
Conservation of gas – It normally refers to natural gas conservation. It refers to the practice of reducing the consumption, waste, and loss of gaseous fossil fuels or maintaining the volume and pressure efficiency of gases in industrial applications.
Conservation of mass – It relates to the first laws of thermodynamics, which states that for any system closed to all transfers of matter, the mass of the system must remain constant over time. The law implies that mass can neither be created nor destroyed, although it can be rearranged in space, or the entities associated with it can be changed in form.
Conservation of mass principle – The principle of mass conservation states that the mass change of each species in a system result from the migration of species through boundaries and the mass changes because of the chemical reactions, represented by a mass balance equation.
Conservation of materials – It is the operational principle used to calculate material balances (or mass balances) across metallurgical processes. The total mass of raw materials entering a process is to equal the total mass of the products, by-products, and waste leaving it. It also refers to extending the lifecycle of metallic elements to prevent resource depletion.
Conservation of natural resources – It means the sustainable management, protection, and rational use of earth’s materials to balance human and technological needs with environmental safety.
Conservation of resources – It is the practice of designing and managing industrial processes, materials, and energy systems to minimize waste, optimize efficiency, and promote sustainable development. It ensures that raw materials and power sources last longer while reducing harm to the environment.
Conservative assumption – It is a deliberate choice or input parameter which biases calculations toward a safer, more cautious, or lower-performance outcome to account for unknown variables, measurement errors, or potential risks.
Conservative design procedure – It is a methodology which intentionally builds large safety margins, higher load capacities, or lower stress limits into a system to account for uncertainties, material variations, or potential failure risks.
Conservative force field – It is a vector field where the work done to move a particle between two points is independent of the path taken, and the net work done around any closed loop is zero.
Conservative formulation – It is a way of writing governing differential equations (such as the Navier-Stokes or fluid flow equations) so that fundamental physical quantities, like mass, momentum, and energy, are explicitly conserved across control volumes and discontinuities.
Conservativeness – It is the quality, disposition, or practice of being conservative. It means favouring traditional values, established institutions, and gradual or cautious change rather than rapid, radical, or experimental innovations.
Conservative variables – These are the set of fundamental physical quantities directly stored and updated in flux-based conservation laws (such as the Euler or Navier-Stokes equations).
Conservator system – A conservator is connected by piping to the main transformer tank which is completely filled with oil. The conservator also is filled with oil and contains an expandable bladder or diaphragm between the oil and air to prevent air from contacting the oil. Air enters and exits the space above the bladder / diaphragm as the oil level in the main tank goes up and down with temperature. Air typically enters and exits through a desiccant-type air dryer which is to have the desiccant replaced periodically. The main parts of the system are the expansion tank, bladder or diaphragm, breather, vent valves, liquid-level gauge and alarm switch. Vent valves are used to vent air from the system when filling the unit with the oil. A liquid-level gauge indicates the need for adding or removing transformer oil to maintain the proper oil level and permit flexing of the diaphragm.
Conserved energy – It refers to the principle that the total quantity of energy within an isolated or closed system remains constant over time.
Conserved quantity – It is a physical property or scalar function of a system which remains strictly constant over time within a closed or isolated system, meaning it cannot be created or destroyed, only transported or transformed.
Consignee – It is a person, or organization which receives a consignment.
Consignor – It is a person, or organization which prepares a consignment for transport.
Consistency – it is an imprecise measure of the degree to which a grease resists deformation under the application of a force. In refractories, consistency is the degree of mobility of a refractory castable as determined by the standard.
Consistency condition – It refers to the requirement which the new stress state following a stress increment must lie on a modified yield surface, necessitating changes in the yield surface to accommodate the stress increment. In plasticity theory, the consistency condition needs that during plastic deformation, the updated stress state is to continuously remain on the active yield surface. It means that any incremental change in stress is not to push the material outside or inside the elastic-plastic boundary defined by the yield function f = 0. In the numerical solution of differential equations (like finite difference or finite element methods), consistency condition needs that the local truncation error approaches zero as the discretization steps (time step dt and grid spacing dx) approach zero. In concrete and soils, consistency condition refers to the relative mobility, fluidity, or resistance of a freshly mixed material (such as concrete or soil) to deformation and flow under an applied force. It also refers to a mathematical or physical rule ensuring that a system, model, or material state remains valid, continuous, and free of contradictions when forces, stress, or data change.
Consistency factor – It is a parameter in the Ostwald-de Waele power law model used to describe non-Newtonian (pseudo-plastic or dilatant) fluids.
Consistency index – It is also called relative consistency. It measures the firmness or relative stiffness of fine-grained cohesive soils (such as clays and silts) in their natural state.
Consistency parameter – It refers to the initial and operational parameters of a battery, such as capacity and internal resistance, which are influenced by manufacturing variations and operational environments. These parameters are important for diagnosing cell inconsistency within battery packs. It is also a scalar multiplier used in plasticity theory and constitutive modelling to scale the plastic flow direction and determine the magnitude of plastic deformation.
Consistency relation – It is a mathematical or logical constraint that ensures a system, model, or material state remains free of contradiction, preserves conservation laws, or adheres to physical limits during changes or transitions.
Consistency rule – It is a logical condition or constraint applied to a model, system, or dataset which evaluates to true or false to ensure multiple data items or structural elements remain aligned and non-contradictory. It is a requirement which ensures the content of multiple data items is aligned with each other, such as ensuring that an end date is not earlier than a start date.
Consistency test – It is a laboratory procedure used to find the exact quantity of water needed to produce a cement paste of standard fluidity or solidity.
Consistent engineering practice – It is the disciplined application of repeatable processes, uniform standards, and reliable daily habits which allow engineering teams to deliver stable, high-quality results over time rather than relying on sporadic bursts of effort.
Consistent estimator – It is a statistical rule or formula whose calculated value converges in probability to the true population parameter as the sample size grows infinitely large.
Consistent mass matrix – It is a discrete representation of a continuous body’s mass computed using shape interpolation functions (N) rather than lumping all mass onto nodal points.
Consistent practice – It means repeating an activity or skill regularly, dependably, and in a similar way over time without long, random gaps.
Consistent system of units – It is a set of units where derived units are calculated directly from fundamental base units through physical laws (such as Newton’s second law, F = m x a) without needing conversion factors.
Consistometer – It is a specialized laboratory or production testing instrument used to measure the physical consistency, flow rate, and rheological behaviour of highly viscous fluids, semi-solids, or plastic substances. Rather than determining absolute dynamic viscosity through applied shear stress (like a traditional viscometer), a consistometer evaluates consistency by measuring how far or how fast a material flows, deforms, or slumps under its own weight or controlled conditions over a specific time interval.
Consolidated clay – It refers to fine-grained cohesive soil which has undergone volume reduction because of the expulsion of pore water under applied effective stress.
Consolidation – In metal-matrix or thermoplastic composites, it is a processing step in which fibre and matrix are compressed by one of several methods to reduce voids and achieve desired density.
Consolidation characteristics – These characteristics define how a saturated soil compresses and settles over time when subjected to a static load, driven by the gradual expulsion of water from its pore spaces. It refers to the set of physical and time-dependent behavior traits which describe how soil volume decreases and transfers applied stress from pore water to the soil skeleton.
Consolidation of powder – It is the process of turning loose metal or ceramic powder into a hard, solid shape with high density and strength. Consolidation combines loose particles into a cohesive structure without melting the main metal. It typically happens in two main stages namely compaction (pressing), and sintering (heating).
Consolidation parameters – These are values measured from soil tests (such as the oedometer test) to predict the magnitude and rate of volume change (settlement) when saturated fine-grained soils like clay are subjected to an applied load.
Consolidation process – It refers to the method of redesigning a multiple part assembly into a single component while maintaining the same operational functionality, hence simplifying the part, improving performance, and reducing costs associated with labour, tooling, and inventory.
Consolidation rate – The rate of consolidation is the speed at which saturated, fine-grained soil (such as clay or silt) expels pore water, transfers external loads to the soil skeleton, and undergoes volume reduction (settlement) over time.
Consolidation settlement – It is the gradual, time-dependent sinking or vertical displacement of a structure which occurs when saturated, fine-grained soil (such as clay or silt) compresses under an applied load.
Consolidation theory – It is an analytical framework used to evaluate the gradual volume reduction and time-dependent settlement of saturated, fine-grained soils (such as clays and silts) under sustained static loads.
Consolidation time – It is the duration needed for excess pore water pressure in saturated soil to dissipate after a load is applied, causing the soil skeleton to compress and transfer the stress to the soil particles.
Consortium – It is a temporary partnership of two or more independent organizations which pool their resources and skills to complete a large project.
Constant amplitude fatigue tests – These tests involve applying a repeating stress cycle to a material, where each cycle is identical in terms of amplitude and form. This type of testing is used to determine a material’s ability to withstand fatigue (fracture) under repetitive loading conditions. The stress amplitude is the difference between the maximum and minimum stress levels in each cycle.
Consonant-vowel-consonant structure – It refers to a three-letter (or three-phoneme) word or syllable pattern consisting of a consonant sound, followed by a vowel sound, and ending with another consonant sound. Consonant-vowel-consonant (CVC) syllables are the foundational building blocks used in speech synthesis, voice recognition, and phonetic testing (such as consonant-vowel-consonant log-atoms or mono-syllabic word lists used to evaluate acoustic transmission and intelligibility).
Constantan – It is a copper-nickel alloy (roughly 55 % copper and 45 % nickel) valued for its stable electrical resistance across changing temperatures. It features a very low temperature coefficient of resistance, high ductility, and good corrosion resistance, making it a staple for precision electrical and thermal measurement devices.
Constantan wire – It is a precision resistance alloy wire made of around 55 % copper and 45 % nickel (Cu55 / Ni45). Its defining engineering feature is an exceptionally low temperature coefficient of resistance (TCR), meaning its electrical resistance remains nearly constant across wide temperature variations.
Constant acceleration – It is a type of motion where an object’s velocity changes by an equal quantity in every equal interval of time, meaning the acceleration vector remains completely fixed (constant) over the duration of the movement.
Constant amplitude – It refers to a loading or oscillatory condition where the peak value, stress range, or signal magnitude remains uniform and unchanging throughout each cycle.
Constant amplitude loading – It refers to a cyclic loading pattern where the maximum and minimum stress levels remain the same throughout the entire duration of the test or service life. It is the simplest form of fatigue testing and is mainly used to determine a material’s baseline resistance to fatigue failure.
Constant amplitude loads – These are repeating load or stress cycles which maintain the exact same peak, valley, mean value, and wave-form pattern over time.
Constant angular velocity – It is a rotational state where a body or shaft rotates at a uniform rate around a fixed axis, covering equal angular displacement in equal intervals of time.
Constant background – It refers to a nearly flat or constant signal in scattering data, which can arise from incoherent scattering cross-sections, instrumental imperfections, or short-range fluctuations in scattering-length density within samples. This background typically is to be subtracted to accurately analyze structural details in scattering experiments.
Constant charge – It refers to an electric charge ‘Q’ which remains fixed in magnitude and does not vary over time [q(t) = Q], or to a system where the net electric charge is conserved and unchanging.
Constant coefficient – It is a fixed numerical or parameter value multiplying a variable, derivative, or state in a mathematical model (such as a differential or difference equation) which does not change with time or space.
Constant component – It is the DC (direct current) or zero-frequency term in a Fourier series representation of a signal, representing the non-oscillatory, time-invariant baseline level. As engineering constants (materials science), it means quantities which physically characterize a material’s mechanical response, such as Young’s modulus, shear modulus, or Poisson’s ratio, which remain invariant for a given linear elastic material. In electrical engineering and electrochemical impedance spectroscopy (EIS), it an equivalent circuit component used to model non-ideal capacitive or double-layer behaviour where the phase angle remains constant across a frequency range. In component engineering (life-cycle management), it is a discipline focused on selecting, qualifying, standardizing, and managing physical hardware and electrical components across a product’s life-cycle to ensure reliability and mitigate obsolescence.
Constant conveying – It refers to a continuous and steady movement of bulk materials or piece goods through a system at a uniform mass flow rate or velocity over time.
Constant current power source – It is a power supply which maintains a stable current output, normally used for driving laser diodes and LEDs (light-emitting diodes) to ensure consistent light emission, hence improving stability and efficiency in different applications.
Constant current sink – It is an electronic circuit or device which draws a fixed, pre-determined quantity of electrical current from a load regardless of the voltage changes across its terminals.
Constant current source – It is an electronic circuit or device which delivers a fixed, steady electrical current to a load, regardless of changes in the load’s resistance or the voltage across its terminals.
Constant deceleration – It refers to a uniform, steady rate of decrease in an object’s velocity over time. This means the speed drops by an equal quantity during each equal time interval. It is also known as uniform negative acceleration.
Constant-deflection test – It is a mechanical testing method used mainly to evaluate a metal’s susceptibility to environmental cracking, such as stress corrosion cracking (SCC) and hydrogen embrittlement (HE). During the test, a smooth or pre-cracked metallic sample is bent or deformed to a fixed, specified physical distance (deflection) and rigidly held in that position by a fixture or frame while being exposed to a corrosive environment.
Constant density – It means that the mass per unit volume of a material or fluid remains completely unchanged across space and time.
Constant-displacement test – It is a mechanical testing method where a metal sample is deformed or deflected to a fixed, predetermined displacement and held at that position to evaluate stress relaxation, cracking resistance, or environmental degradation.
Constant drying rate period – It is the phase of a drying process where water evaporates from the surface of a wet material at a steady, unchanging rate per unit area.
Constant effective fracture-strain criterion – It is a fundamental phenomenological model used to predict ductile failure. It states that ductile fracture occurs instantly when the equivalent (or effective) plastic strain within a material reaches a single, fixed critical threshold value, regardless of the stress state, loading history, or stress triaxiality.
Constant electric field – It is also called static uniform electric field. It is an electro-magnetic field which does not change over time (0 hertz frequency) and maintains the same magnitude and direction at every point in space.
Constant exhaust velocity – It is a modelling assumption where the effective exhaust velocity of a rocket or jet engine is treated as a fixed, unchanging value rather than a variable over time or altitude.
Constant extension rate tensile testing – It also known as slow strain rate testing (SSRT). It is a material testing method where a sample is subjected to a constant rate of elongation, with the applied load adjusted to maintain that consistent extension rate. This is a standard test used to evaluate a material’s mechanical properties, frequently for metals, especially in corrosion testing.
Constant failure rate – It is the period when the probability of a component or system failing per unit of time remains uniform and flat, regardless of how long it has been operating.
Constant false alarm rate – It is an adaptive signal processing technique used in radar, sonar, and lidar systems to automatically adjust target detection thresholds.
Constant flexural rigidity – It refers to a structural condition where a beam or member maintains a uniform, unchanging resistance to bending across its entire length. It is characterized by constant values of the modulus of elasticity (E) and the moment of inertia (I). This property allows for predictable slope deflection behaviour when subjected to bending moments.
Constant flow rate – It describes a fluid process where the volume or mass of fluid passing a point per unit of time stays completely unchanged over time.
Constant flow system – It is very frequently used in HVAC (heating, ventilation and air conditioning) heating and cooling loops or fluid transport—where the volume flow rate of the working fluid remains fixed or changes only slightly (typically around 75 % to 110 % of the nominal value) regardless of fluctuations in the actual thermal or mechanical load.
Constant heat flux – It is also called uniform heat flux. It is a thermal boundary condition where the rate of heat transfer per unit area passing through or applied to a surface remains completely uniform and unchanged.
Constant height – It is a vertical measurement system where points maintain a fixed potential energy level rather than a strictly geometric distance from the ground. It is a parameter used when designing architectural or structural elements like floors or roofs. It is also a modelling assumption used in subterranean rock mechanics and fluid dynamics.
Constantinescu and Ballard method – It is frequently referred to as the Ballard-Constantinescu reconstruction. It is a mathematical framework used to invert and map subsurface residual stresses based on destructive surface stress measurements. The method provides closed-form, analytical solutions to reconstruct a material’s complete original internal stress state.
Constant intensity pyrometer – It is an optical temperature-measurement tool where an operator adjusts the current through an internal lamp filament until its luminous intensity matches the thermal radiation intensity of a hot target, making the filament blend into the background to read the temperature.
Constant life diagram – It is referred to as a Haigh diagram or Goodman diagram. It is a graphical engineering tool used to predict and evaluate the fatigue life of a material or component under combined mean stress and alternating stress (cyclic loading).
Constant life fatigue diagram – In failure analysis, it is a graph (normally on rectangular coordinates) of a family of curves, each of which is for a single fatigue life (number of cycles), relating alternating stress, maximum stress, minimum stress, and mean stress. The constant life fatigue diagram is normally derived from a family of S-N curves, each of which represents a different stress ratio for a 50 % probability of survival.
Constant load test – It is a mechanical testing method where a fixed, unchanging force or weight is applied to a metal sample for a specified duration to measure how it deforms or fails under continuous stress.
Constant Mach number – It refers to a flight or flow condition where the ratio of an object’s speed (or local fluid velocity) to the local speed of sound remains unchanged over time or distance (M = u /c = constant). It is a pure number without units, representing the balance between inertial forces and fluid elasticity (compressibility).
Constant magnitude – It means that the gain (or amplitude response) of a system remains completely unchanged across a specific range of frequencies or operating conditions. It indicates that the system does not amplify or attenuate signals as their frequency shifts.
Constant modulus – It is a signal property or design constraint where the time-domain envelope (amplitude) of a waveform remains strictly constant, meaning only the phase changes. It is also a fundamental property or proportional constant measuring how much a solid material resists deformation when an external force or stress is applied.
Constant moisture content – It refers to a condition where the moisture level in the air remains unchanged while the air temperature is reduced, ensuring that all parts of the cooling coil surface temperature are above the dew-point temperature of the entering air-stream.
Constant normal load – It is a fixed vertical force applied to a test sample or interface which remains unchanged throughout a test or operational process, even if the sample expands, compacts, or deforms during shear application.
Constant normal stiffness – It is a boundary condition used in geotechnical and rock engineering (such as during direct shear testing of rock joints or faults) where the normal stress acting on a shear plane changes dynamically in response to the dilation or contraction of the interface. Instead of keeping the normal load fixed, which happens in constant normal load (CNL) tests, the surrounding rock mass is modelled as a linear spring that resists the lifting or expanding (dilation) of the joint.
Constant Poisson ratio – It is readily shown on the basis of the correspondence principle—is equivalent to imposing the same time dependence on the shear and extension behaviour of the material, i.e., the shear modulus and the uniaxial modulus differ by a constant factor. This approximation is, hence, particularly useful when the dominant application time frame falls into the more extreme (short or long) ranges of the material response.
Constant potential – It refers to a state or operating mode where the electric potential (voltage) between two or more points remains uniform and fixed over time, regardless of fluctuations in current, load, or chemical state.
Constant power mode – It is an operating state where a power supply, electronic load, or converter maintains a fixed power consumption or output (P), regardless of changes in input or load voltage (V).
Constant-pressure boundary – It is a highly permeable feature where pressure disturbances from a well test do not affect the pressure at that boundary, allowing the well to stabilize at a constant pressure similar to that of a nearby aquifer or injection well. This model is normally applied in scenarios where reservoir pressure is supported by fluid encroachment.
Constant pressure drop – It is an approach to scale up mixing and mass transfer processes while maintaining a constant pressure drop across flow reactors, thereby avoiding issues related to increased pressure drop and allowing for nearly constant mixing and mass transfer performance.
Constant pressure specific heat – It is the quantity of energy change of a system because of a temperature change under constant pressure, accounting for both work done to the surroundings and changes in internal energy. This property becomes particularly relevant in processes where volume changes are important.
Constant quantity – It is a fixed value or parameter which does not change throughout a specific problem, system model, or mathematical context.
Constant radius – It normally refers to a feature, curve, or path that maintains a fixed, unchanging radius of curvature across its geometry or operational cycle. It also refers to a method in forming processes where the tool radius remains unchanged across all forming passes. This approach ensures uniformity in the curvature of the formed section.
Constant rate period – It is the stage of drying during which the moisture content decreases from the initial level to the critical moisture content, characterized by a constant rate of drying per unit area.
Constant rigidity – It means a material or beam maintains an unchanging resistance to bending or deformation along its length.
Constant rotational speed – It means that a rotating object or shaft turns around an axis at a completely uniform, unchanging rate over time, with zero angular acceleration.
Constant specific heat – It refers to the specific heat of a material which does not vary considerably with temperature, normally applicable to solids where the specific heat at constant volume and constant pressure are virtually indistinguishable. It can be measured by determining the heat input needed to raise the temperature of the material by a certain quantity.
Constant speed drive – It is a transmission type needing constant speed input, typically composed of a hydraulic transmission with mechanical controls.
Constant speed wind turbines – These are turbines which operate with a fixed angular speed of the rotor, regardless of the wind speed, typically using induction or synchronous generators. They are characterized by simple and reliable electrical construction but experience higher mechanical stresses, necessitating additional safety factors in their design.
Constant spring – In this type of spring, the supported load remains the same throughout deflection cycle.
Constant-strain test – It is frequently referred to as a constant-displacement or fixed-strain test. It is a mechanical testing method where a metal sample is deformed to a specific, pre-determined level of strain (displacement), which is then kept strictly constant over time. Instead of varying the force or letting the material continuously stretch, the physical dimensions / displacement of the testing frame or clamping fixture are locked in place. Metallurgists monitor how the internal stress changes over time or how the material degrades under this fixed deformation.
Constant strain triangle – It is a finite element used in solid mechanics which predicts constant strain throughout its volume but is prone to inaccuracies, such as spurious shear strains, particularly in bending problems. It is mainly characterized by its linear triangular shape and limitations in representing bending behaviour accurately.
Constant stream – It refers to a continuous, uninterrupted flow, series, or succession of things, people, vehicles, data, or physical matter happening or moving without stopping.
Constant stress – It refers to a steady, unchanging mechanical load or force maintained on a structure, component, or test sample over time. It is a fixed load (such as the self-weight of a bridge, pre-tension in a bolted joint, or press-fit assembly pressure) which remains uniform and static rather than fluctuating.
Constant temperature anemometer – It is a type of thermal (hot-wire or hot-film) anemometer which measures fluid velocity and turbulence by keeping the temperature, and hence the electrical resistance, of a fine sensor element strictly constant.
Constant temperature anemometry – It is a precise variant of hot-wire anemometry which measures flow velocities and turbulent flow variables with high temporal resolution. Its mobility and versatility allow it to be used in a wide variety of flow applications.
Constant temperature evaporation – It refers to the phase change process where a liquid turns into a vapour at a fixed, uniform temperature while absorbing latent heat of vapourization under constant pressure.
Constant temperature gradient – It refers to a spatial rate of temperature change which remains uniform and unchanging over a specific distance or cross-section.
Constant temperature process – It is known in thermodynamics as an isothermal process. It is a thermodynamic change in a system during which the temperature remains strictly constant (dT=0).
Constant thickness – It means that a component or material layer maintains the exact same cross-sectional measurement (thickness) across its entire geometry, regardless of where it is measured.
Constant total pressure – It refers to a condition where the total pressure in a reaction system is maintained steady while varying other parameters, such as the fuel partial pressure, to influence reaction rates and dynamics.
Constant vector – It is a vector whose magnitude (length) and direction remain completely unchanged with respect to time, position, or any other independent variable.
Constant velocity – It means an object or system moves with an unchanging speed along a straight path (zero acceleration), or, in mechanical drives like a constant velocity (CV) joint, an input shaft transmits the exact same angular output speed throughout a full revolution without speed fluctuations, even when the shafts are angled.
Constant vertical load – It is a fixed, downward force, directed along the vertical or gravity axis, which remains unchanged in magnitude and position during a test, operation, or structural analysis.
Constant voltage operation – It is a mode where a power source maintains a fixed, stable output voltage regardless of changes in the connected load resistance, allowing the output current to vary freely as per the Ohm’s law (I = V/R).
Constant volume – It refers to a simulation condition where the volume of the system remains fixed, typically alongside constant energy, allowing for the analysis of thermodynamic properties without changes in system size. This approach is frequently contrasted with simulations which allow for fluctuations in volume or particle number.
Constant volume assumption – It is also called isochoric assumption. It states that the total volume (V) of a thermodynamic system or control volume remains fixed (dV = 0) throughout a process or analysis.
Constant volume process – It is also known as an isochoric process, isometric process, or isovolumetric process. It is a thermodynamic process in which the volume (V) of a closed system remains completely unchanged (V1 = V2) or (dV = 0) while heat is added or removed.
Constant volume specific heat – It is the quantity of heat energy needed to raise the temperature of a unit mass (or one mole) of a substance by one degree (Celsius or Kelvin) while keeping its volume fixed.
Constant wall temperature – It is also called a constant surface temperature or Dirichlet boundary condition). It is a thermal boundary condition where the temperature of a solid wall or boundary surface is fixed and remains uniform across space and time (Tw = constant) during heat transfer or fluid flow.
Constant wall thickness – It is a design rule stating that a manufactured part, casting, or hollow section is to maintain a uniform, equal thickness across its entire structure.
Constant water content – It refers to a process where the actual quantity of water vapour in the air remains unchanged while the air temperature is lowered.
Constant water content triaxial test—it describes a condition where a soil sample is sheared without allowing water to drain into or out of the sample (no change in the overall mass of water inside).
Consteel electric arc furnace process – In the electric arc furnace with the Consteel process, the adopted plant solution is the continuous feeding of electric arc furnace by the scrap, pre-heated and conveyed through a conveyor moving in a pre-heating tunnel, in which the exhaust gas from electric arc furnace, flowing counter current of metallic charge is combusted by injected air. The continuous feeding and preheating of scrap offer some potential advantages compared to the conventional electric arc furnace batch feeding.
Constellation diagram – It is a graphical representation used to analyze the impact of interference on a signal. It shows how interference, such as continuous wave signals or noise, can cause points in the diagram to spread out or blur, affecting the quality of the received signal.
Constellation point – It is a specific coordinate in a complex signal space diagram which represents a unique symbol (a combination of bits) sent over a communication channel.
Constituent – It is one of the ingredients which make up a chemical system. It is also a phase or a combination of phases which occurs in a characteristic configuration in an alloy micro-structure.
Constituent component – It refers to an individual, distinct part, software module, hardware element, or raw material which combines with other parts to form a larger, functional system or assembly.
Constituent materials – These are the individual, distinct components which combine to form a composite material. Each constituent retains its own physical and chemical identity on a macroscopic level rather than dissolving or blending into a single uniform substance.
Constituent molecules – These molecules refer to the individual, fundamental molecules which assemble, aggregate, or bond to build larger molecular structures, clusters, or composite materials.
Constituent particle – It refers to a basic component, phase, or sub-unit which combines to form a larger material structure, micro-structure, or composite system.
Constitution diagram – It is also known as phase diagram. It is a graphical representation of the temperature and composition limits of phase fields in an alloy or ceramic system as they actually exist under the specific conditions of heating or cooling. A constitution diagram can be an equilibrium diagram, an approximation to an equilibrium diagram, or a representation of metastable conditions or phases.
Constitutional isomer ceramics – These are also known as structural isomers. These refer to ceramic materials where the arrangement of atoms (the ‘connectivity’ of the atoms) within the crystal structure differs, even though they have the same chemical formula and overall composition. This concept is analogous to constitutional isomerism in organic chemistry, where molecules with the same molecular formula can have different arrangements of atoms. Constitutional isomers, are compounds which share the same chemical formula but differ in the way their atoms are connected (their bonding). This difference in connectivity leads to variations in their properties and behaviour. Constitutional isomers arise when the crystal structure of a ceramic material allows for different arrangements of the constituent atoms or ions while maintaining the overall chemical composition.
Constitutional supercooling – it is a solidification phenomenon in alloys where the local liquidus temperature ahead of the solid-liquid interface exceeds the actual temperature of the melt because of a buildup of rejected solute. It occurs not from a drop in the bulk temperature, but from a compositional change (constitution) in the liquid boundary layer.
Constitutional undercooling – It refers to the condition where the melt temperature is below the liquidus temperature because of a change in composition rather than temperature, resulting in a film of undercooled liquid adjacent to the solid-liquid interface. This phenomenon can lead to the formation of stable structures such as cells and dendrites in the solidifying material.
Constitution point – It is a specific location on a phase diagram which indicates the number of phases present (one or two) based on the temperature and composition of an alloy.
Constitutive equation – It is a mathematical relationship which describes the flow stress of a material in terms of the plastic strain, the strain rate, and temperature. It is a mathematical model which defines the relationship between stress and strain for a specific metal under given physical conditions. Unlike universal thermodynamic conservation laws, these equations describe how a specific metal responds to mechanical loading, incorporating material constants that depend directly on its microstructure, chemical composition, and processing history.
Constitutive model – It is a mathematical equation or relation which describes how a specific material deforms, flows, or responds when subjected to external forces, temperatures, or environmental loads. These models bridge the gap between universal physical laws (such as conservation of mass, momentum, and energy) and the unique physical behaviour of a real material. They very frequently define the relationship between stress (internal resistance) and strain (deformation).
Constitutive modelling – It is the process of creating mathematical equations which define how a material responds to external forces, loads, temperatures, or environmental conditions.
Constitutive relations – These relations are mathematical formulations which describe the mechanical behaviour of materials, frequently expressed as functional relationships between stress, strain, strain rate, and temperature.
Constitutive relationship – It is a mathematical expression which defines how a specific material responds to external forces, energy inputs, or environmental changes.
Constrained application protocol – It is a lightweight application-layer web transfer protocol for use with resource-constrained nodes and low-power, lossy networks in the internet of things (IoT).
Constrained flow stress – It is the instantaneous stress needed to maintain plastic deformation in a material when its volumetric or directional flow is physically limited by tooling, friction, or multi-axial loading states. While uniaxial flow stress represents a material’s intrinsic resistance to continuous plastic flow under unconstrained conditions (e.g., a standard tensile test), constrained flow stress accounts for external mechanical restrictions which artificially raise the needed forming force.
Constrained optimization problem – It is the process of finding the best values for a set of design variables to minimize or maximize a performance metric (such as cost, weight, or energy consumption) while strictly satisfying a set of physical, geometric, or operational limits.
Constrained problem – It is the formal process of establishing the boundaries, rules, and mathematical or physical limits within which a design solution is to operate. Unlike evaluation criteria or performance desires, constraints are absolute ‘pass / fail’ or ‘yes / no’ conditions, violating a single constraint invalidates the entire solution.
Constrained recovery devices – These are components made from shape memory alloys (SMAs) designed to generate high mechanical forces or sealing stresses rather than undergoing dimensional motion. Unlike applications where an shape memory alloy acts as a kinetic actuator to move a component, a constrained recovery device is intentionally blocked from returning to its pre-deformed shape upon thermal activation. The material’s attempt to change its shape is instead converted into a high contact pressure or residual stress.
Constrained thermal test – It refers to a testing methodology where a material, component, or structure is subjected to temperature changes while its natural physical expansion or contraction is mechanically restricted by boundaries or surrounding structures. Unlike free thermal testing (where material changes size freely without generating internal stress), a constrained thermal test forces the material to convert its thermal energy into internal mechanical stress. This evaluates how a design tolerates the real-world boundary conditions of rigid physical assemblies.
Constrained unit commitment – It is frequently referred to as security-constrained unit commitment (SCUC). It is a mathematical optimization process used to determine the hourly on / off schedule (commitment) and power output (dispatch) of power-generating units over a set time horizon (typically 24 hours to 48 hours). The main goal is to minimize total production, start-up, and shut-down costs while strictly satisfying electrical demand and physical or security limits of the power grid.
Constraint – It is a restriction which limits the transverse contraction normally associated with a longitudinal tension and that hence causes a secondary tension in the transverse direction. It is normally used in connection with welding. Constraints are the absolute limits, rules, and boundaries which a design or project is to satisfy to be considered successful. Unlike criteria (which describe the desired features and performance targets people want to maximize), constraints are binary, i.e., a design either meets them or it fails.
Constraint analysis – It is the systematic process of identifying, defining, and evaluating the physical, technical, regulatory, and resource boundaries within which a system is to operate. Unlike performance criteria (which can be traded off or optimized), constraints are absolute boundaries. Violating a constraint means the design or solution is invalid.
Constraint condition – It is a specific limitation, rule, or boundary equation which restricts the design space, physical movement, or operating variables of a system. Unlike performance criteria (which one wants to maximize or minimize), constraints are absolute, violating a constraint makes a solution invalid.
Constraint effect – It refers to how the physical geometry, size, depth of a crack, and loading mode of a component restrict plastic deformation at a crack tip. This restriction alters the local stress-strain state, which directly impacts a material’s fracture toughness and failure behaviour.
Constraint equation – It is a mathematical expression which defines a physical limitation, geometric connection, or rule linking variables (such as nodal displacements, velocities, or generalized coordinates) in a system.
Constraint factor – It typically refers to a dimensionless scaling parameter which accounts for the restriction of plastic flow (multiaxial stress state) in a material, very frequently used in fracture mechanics, indentation testing, and metal forming. In fracture mechanics, the plastic constraint factor (m) relates the crack tip opening displacement (CTOD) to the J-integral parameter when evaluating the fracture toughness of a material. In hardness and indentation testing, the constraint factor (c) is a scaling factor that relates the uniaxial flow (representative) stress of a material to the higher indentation stress or mean contact pressure.
Constraint functions – These are defined as functions which are used to define the feasible set in optimization problems.
Constraint length – This has different technical meanings depending on the discipline (such as telecommunications / coding, printed circuit board design, or mechanical / structural limits).
Constraint modelling – It is a form of computer modelling in which constraints are used to create a set of rules which control how changes are made to a group of geometric elements (lines, arcs, form features, etc.). These rules are typically embodied in a set of equations. Constraint models are defined as either parametric or variational.
Constraint processing – It is a methodology which defines and manages physical, geometric, material, and regulatory boundaries within a design or system to prune infeasible solutions and guide automated solvers.
Constraint propagation – It is an inference technique in artificial intelligence and constraint programming (CP) which reduces the domains of variables by removing values which cannot possibly be part of any valid solution.
Constraints – These are the boundary conditions, limiting factors, or fixed requirements which dictate how an alloy is designed, processed, or selected for a specific application. They restrict the freedom of the metallurgist and are to be balanced to avoid component failure.
Constraint set – It is the collection of absolute boundaries, limitations, or mathematical restrictions which define the feasible space within which a system, structure, or design are to operate.
Constraint space – It refers to the mathematical and physical process of bounding the allowable motion, configuration, or design choices of a system by applying rules, kinematic joints, or physical limits.
Constraint term – The term ‘constraint’ refers to a limit on the number of kinematic degrees of freedom (DOFs) an object has during its motion in three-dimensional space, affecting its independent motion components.
Constraint violation – It is the degree or state in which a proposed design solution fails to satisfy a specified boundary condition, limit, or rule. It measures how far an infeasible solution strays from the permitted operating or design space. Lower violation values mean the solution is closer to being valid.
Constricted arc (plasma arc welding and cutting) – It is a plasma arc column which is shaped by a constricting nozzle orifice.
Constriction resistance – It is the extra resistance which occurs when an electric current or heat flow is forced to funnel through microscopically small contact points, known as a-spots or asperities, where two surfaces physically touch. Since real engineering surfaces are never perfectly smooth, they only make contact across a tiny fraction of their apparent surface area. This forces the flow lines of electricity or heat to crowd and narrow (constrict” as they pass through these micro-spots, creating a localized drop in voltage or temperature.
Constructability – It is also known as buildability. It is the optimal and timely integration of construction knowledge, expertise, and experience into a project’s planning, design, procurement, and field operations. It ensures that a structure can be built efficiently, safely, and economically using available methods, materials, labour, and site conditions.
Construction – It is the coordinated process of planning, designing, and building structures. It is the systematic process of turning a detailed design and plan into a physical structure or piece of infrastructure.
Construction aggregate – It is a broad category of coarse-grained to medium-grained particulate material which is used in construction. It includes sand, gravel, crushed stone, slag, recycled concrete and geo-synthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt. The aggregate serves as reinforcement to add strength to the overall composite material.
Construction contract – It is the agreement between an owner and a general contractor which outlines the obligations and responsibilities regarding the construction project. This contract serves as a foundational document which can also influence the agreements between the general contractor and any sub-contractors.
Construction design – It is the systematic process of turning project ideas and requirements into detailed technical drawings, calculations, and specifications which dictate how a facility or infrastructure is to be built. It bridges the gap between conceptual planning and physical site execution.
Construction details – These details refer to the specific connections and joints in a structure which are critical to the overall design, influencing aspects such as behaviour, materials, geometry, installation, durability, maintenance, and visual expression. These details inform different characteristics of the entire structure, including its size, stresses, and complexity.
Construction difficulty – It is a metric or evaluation of the operational, environmental, logistical, and technical complexity involved in building a structure. It measures how hard it is to execute design plans safely, on time, and within budget under real-world site conditions.
Construction drawing – This drawing is also known as the working drawing. It provides dimensioned, graphical information which can be used at the construction site for the construction work, or by suppliers to fabricate components of the works or to assemble or install components. Along with specifications and bills of quantities or schedules of work, it forms a part of the ‘production information’, which is prepared by designers and passed to the construction team to enable a project to be constructed. Construction drawing provides an insight into the development of a construction site. These drawings are made in different stages. Some plans are necessary to be made before the construction begins while others are made while the construction is under progress. Construction drawing provides an outlet for the engineers to convey their ideas and concepts regarding a project. It is a means of showing in a graphical form the shape, size and position of a building or equipment on a site, together with the composition of the materials used and the way the building or equipment is to be constructed or put together.
Construction durability – It is a material or structure’s ability to resist weathering, chemical attack, abrasion, and other forms of degradation over its intended service life without losing structural integrity or needing excessive maintenance.
Construction engineer – Construction engineer is a specialized civil engineer who designs, plans, constructs, and manages infrastructure projects such as buildings, roads, bridges, tunnels, and utilities.
Construction engineering – It is a specialized sub-discipline of civil engineering focused on the design, planning, construction, and on-site management of infrastructure projects like buildings, roads, bridges, and utilities.
Construction equipment – It refers to heavy-duty machinery, vehicles, and specialized devices designed to execute civil, structural, and infrastructure construction tasks, ranging from site excavation to vertical lifting.
Construction failure – It is an unacceptable difference between expected and observed performance, or the complete or partial inability of a building element, component, or system to perform its intended function safely and reliably.
Construction group – It refers to organizations involved in construction activities, which can include different types of projects such as civil, and industrial construction, and can differ in ownership structure, such as state-owned or privately held. The group is a collaborative network or corporate organization of specialized entities, including architects, structural and civil engineers, general contractors, sub-contractors, and material suppliers, which join forces to plan, design, and execute building or infrastructure projects.
Construction joints – These are defined as work-related separation surfaces between structures or components, normally occurring when pouring concrete in multiple, consecutive sections. They can be planned, marking transitions between concrete pouring sections, or unplanned, arising from the non-continuous placement of fresh concrete.
Construction management – It is a service which acts as an owner’s agent, providing professional staff and expertise throughout the design and construction stages of a project, ensuring the project is completed efficiently and cost-effectively. It encompasses knowledge of costs, scheduling, and construction methods to aid in project delivery.
Construction manager – Construction manager is a professional who plans, coordinates, budgets, and oversees a construction project from inception to completion, ensuring it is delivered safely, on time, within budget, and to the needed quality standards.
Construction manager at risk – It is a project delivery method where a construction manager acts as a consultant during the design phase and then transitions into a general contractor during construction, committing to finish the project within a ‘guaranteed maximum price’ (GMP).
Construction manager-general contractor– It refers to a project delivery method where a contractor is retained early in the design process to synchronize design and construction, hence improving cost certainty for the project.
Construction method – It is the specific set of techniques, processes, and strategies used by professionals to assemble, build, or execute a structure. It dictates how materials, equipment, and labour are organized on-site or off-site to ensure structural integrity, safety, cost-effectiveness, and compliance with project designs.
Construction methodology – It refers to the techniques and processes used to complete a construction project efficiently and economically, frequently adapting to challenges such as work-force reduction and material costs. It includes approaches like off-site construction, where components are fabricated in a controlled factory setting before being delivered to the construction site for assembly.
Construction monitoring – It is the systematic observation, inspection, and verification of building or infrastructure work to ensure it matches approved designs, technical specifications, safety standards, and contracts.
Construction options – These refer to the different methods and approaches available during the planning and design phases of a project which can be considered to optimize construction safety, cost, schedule, and quality, while accommodating the facility’s operations and maintenance requirements.
Construction permit -It is an official authorization issued by an ‘authority having jurisdiction’ (AHJ) or local statutory authorities which legally allows a project team to begin building, renovating, or altering a structure.
Construction planning – It is the fundamental process of defining how a project is to be executed, including the selection of technology, the break-down of work tasks, the estimation of needed resources and durations, and the sequencing of activities to deliver a structure on time and within budget.
Construction platform – It is a working platform. It is a temporary, engineered load-bearing surface built on a job site. Its core purpose is to safely support heavy construction traffic, cranes, piling rigs, and temporary structures (like scaffolding or formwork props)
Construction principles – These are the fundamental rules, scientific guidelines, and operational standards used to safely, efficiently, and durably build infrastructure and structures. While civil engineering focuses on theoretical design and structural calculations, construction principles focus on how to turn those designs into physical reality.
Construction process – It is the systematic, phased sequence of activities needed to transform an architectural and structural design into a physical building or civil infrastructure project. It bridges conceptual planning with physical execution through structured work-flows, engineering analysis, and resource management.
Construction products – These are goods used in the construction sector which are to meet specific regulations to ensure they are fit for their intended use and facilitate the free circulation of goods within the market. Construction product is also an item or kit manufactured and placed on the market to be permanently incorporated into buildings or civil engineering works, whose performance directly affects the overall requirements of the structure (e.g., cement, structural steel, insulation, windows, cables, and doors). Temporary items like scaffolding are excluded.
Construction products regulation – It is a regulatory framework, originally established by the European Union under Regulation (EU) No. 305/2011 and updated under Regulation (EU) 2024/3110, which creates a single, harmonized set of rules for marketing and testing building materials and civil engineering products. Products falling under harmonized standards is to carry a CE (Conformite Europeenne, which is French for European Conformity) mark to prove they meet required performance and safety criteria.
Construction programme – It is a master engineering and management document which outlines the chronological sequence, duration, and dependencies of all tasks needed to deliver a construction project.
Construction project management – It is the specialized discipline of planning, coordinating, budgeting, and overseeing a building or infrastructure project from initial concept to completion.
Construction rate – It is very frequently known as rate analysis or unit rate. It is the systematic calculation of the total cost needed to complete one measurable unit of a specific work item (such as per cubic meter, per square meter, per running meter, or per piece). Instead of guessing or using a blind lump-sum figure, engineers break the task down into its exact resource requirements.
Construction robot – It is an autonomous, semi-autonomous, or tele-operated mechanical and electronic system designed to perform physical construction tasks, site evaluations, or prefabrication processes. Unlike traditional construction equipment that requires direct manual control for every movement, a construction robot integrates sensors (such as global positioning system, light detection and ranging, and cameras), onboard software, and actuators to perceive its environment, make real-time decisions, and execute repetitive or hazardous operations with high precision.
Construction schedule – It is a written or graphical representation of a contractor’s plan for completing a construction project, emphasizing the elements of time and sequence. It shows the major work items, their logical sequence, and the specific time periods allocated for each activity throughout the project’s duration.
Construction specification – It is a detailed written legal document which defines the quality of materials, the needed standards of workmanship, and the execution methods needed to build a project, functioning alongside visual design drawings.
Construction staging – It consists of dividing a large or complex construction project into chronological phases or geographical sections, treating each part as an interim standalone job site until the full project is complete. It also means a designated, secure temporary zone located on or near a job site used for site logistics.
Construction surface – It refers to creating an accurate, mathematical geometric representation of a free-form or complex 3D shape inside a computer-aided design (CAD) environment. It utilizes mathematical models to accurately define the shape and features of the surface.
Construction team – It is a group of professionals and skilled workers from different technical and operational disciplines who collaborate to execute, build, and deliver a temporary construction project.
Construction traffic – It refers to the vehicular movement, heavy machinery transport, and logistics associated with the demolition, building, repair, or replacement of infrastructure projects (excluding private cars carrying daily site workers).
Construction type – It refers to the classification of a building based on the combustibility of its materials and the fire-resistance ratings of its structural and non-structural components. Defined by building codes like the International Building Code (IBC) Chapter 6, these classifications dictate maximum allowable building heights, floor areas, and design flexibility.
Construction waste management – It is a systematic approach to minimizing, handling, reducing, recycling, and safely disposing of waste materials generated during building construction, renovation, and demolition projects.
Construction work – It is the organized, sequential execution of building, civil engineering, or engineering construction operations to create, alter, repair, maintain, or demolish a physical structure or infrastructure.
Constructive interference – It happens when two or more waves meet while traveling in the same medium and align in phase, combining their amplitudes to create a larger resultant wave.
Constructive parameter – It is a structured methodology in systems engineering and software architecture used to define, constraint, and manage system parameters to guarantee that a system is physically buildable, mathematically valid, and computationally stable. Instead of defining parameters arbitrarily, this approach uses constructive logic, meaning every parameter is to be derived from a verified set of base rules, dependencies, and physical or logical constants.
Constructive remodelling – It is the molecular mechanism by which a polymer self-heals or strengthens under mechanical stress. It is also the engineering process of modifying a building’s existing layout or load-bearing framework to serve a new purpose while ensuring structural integrity and safety standards are maintained.
Consulting engineer – Consulting engineer is a licensed professional or organization providing independent expert advice, analysis, design, and project management services to private organizations, individuals, and government agencies on a contract or project basis.
Consulting engineering organization – It consists of an independent team with substantial experience in a specific area, such as waste-to-energy (WTE) implementation, which provides valuable insights, expertise, and support in different project phases, including feasibility studies, project financing, and procurement processes.
Consulting organization – It is a professional service organization which provides expert advice, specialized skills, and objective analysis to organizations in exchange for a fee. Consulting organizations offer an external, unbiased perspective and specialized capabilities that an organization can lack internally.
Consumable arc melting – It is widely known as vacuum arc remelting (VAR). It is a secondary metallurgical refining process where an electric arc melts a self-sacrificing metal electrode to produce high-purity ingots.
Consumable electrode – It is a general term for any arc welding electrode made chiefly of filler metal. Use of specific names such as covered electrode, bare electrode, flux cored electrode, and lightly coated electrode is preferred.
Consumable electrode arc melting – It is an advanced secondary metallurgical refining process where an electric arc progressively melts an electrode made of the metal alloy itself to purify it and cast a high-integrity ingot.
Consumable electrode remelting – It is a process for refining metals in which an electric current pass between an electrode made of the metal to be refined and an ingot of the refined metal, which is contained in a water-cooled mould. As a result of the passage of electric current, droplets of molten metal form on the electrode and fall to the ingot. The refining action occurs from contact with the atmosphere, vacuum, or slag through which the drop falls.
Consumable insert – it is pre-placed filler metal which is completely fused into the joint root and becomes part of the weld.
Consumables – These are materials which participate in or are needed for a manufacturing process, but do not form part of the end product. Items which are substantially or totally consumed during a manufacturing process are deemed to be consumables.
Consumable spares – These are regularly used items such as fasteners, seals, gaskets, and fuse etc. These are normally low value items.
Consumer – It is a device, component, sub-system, or physical system which uses, draws, or dissipates a resource (such as electrical power, fluid, data, or thermal energy) from a source or network.
Consumer behaviour – It is the study of how individuals, groups, or organizations select, purchase, use, and dispose of goods, services, ideas, or experiences to satisfy their needs and desires. It examines the psychological, emotional, social, and economic factors which drive people choices in the market-place.
Consumer device – It refers to an electronic equipment designed, manufactured, and marketed for every day, personal, or household use rather than for industrial, commercial, or specialized enterprise operations.
Consumer electronics – It refers to the branch concerned with the design, manufacturing, and operation of electronic devices intended for every day, non-expert personal and household use. These electronics are engineered for high-volume manufacturing with strict per-unit cost constraints, balancing component life-span with market affordability.
Consumer energy use – It is the pattern and quantity of energy consumed by end-use entities, such as residential homes, commercial buildings, or industrial facilities, to power their operations, devices, and systems. It is typically quantified in kilowatt-hours (kWh) for electricity or equivalent units for thermal / gas energy over a specific time-frame.
Consumer organizations – These organizations are advocacy groups which seek to protect people from corporate abuse like unsafe products, predatory lending, false advertising, astroturfing and pollution.
Consumer product safety – It is the protection of the public from unreasonable risks of injury, illness, or death associated with consumer goods used in daily life. It is achieved through education, safety standards, regulation, and enforcement by statutory authorities.
Consumer risk – It is also called beta risk. It is the probability that a customer or quality test is going to accept a batch of goods or a process as good, even though it is actually defective or fails to meet needed standards. It is also known as a Type II error or false negative.
Consumer wastage – It is the loss, destruction, or discarding of resources, or goods by end-users after they have been acquired or made available for consumption. It refers to avoidable or unavoidable losses which occur at the final consumption stage, rather than during manufacturing or wholesale transport.
Consumer willingness – It is a customer’s psychological and behavioural readiness to engage with, buy, or pay for a product, service, or brand. This concept is divided into several specific sub-types namely willingness to pay (WTP), willingness to buy (WTB), willingness to pay more (WTPM), and willingness to contribute / sacrifice.
Consuming application – It is an application which utilizes data sets to source a reporting and analytics programme based on organization-driven needs, ensuring relevance and feasibility of execution by identifying data requirements and assessing data quality and usability.
Consuming country – It is a nation which considerably utilizes and absorbs natural resources, energy, or commodities (such as oil, gas, or raw materials) for domestic use, manufacturing, and daily economic activity rather than primarily exporting them.
Consuming party – It is an entity, department, or an organizational unit which utilizes, purchases, or integrates resources (such as software, raw materials, shared services, or data) provided by an external supplier or an internal parent organization.
Consuming process – It refers to any activity, system operation, or economic phase which uses up, depletes, or utilizes resources (such as energy, time, materials, or money) to achieve a specific result. It is the act of using goods, services, or economic resources to satisfy human wants, needs, or manufacturing requirements. It is also an energy-utilizing activity within a system, such as a sensor node in a wireless sensor network, which includes actions like sensing, contention, transmission, idle listening, over-hearing, and managing control packet overhead.
Consumption – It measures the physical use of a material by the user. For example, metal consumption estimates, unlike steel demand figures, account for changes in inventories.
Consumption modelling – It is the process of creating mathematical, physical, or data-driven representations to predict, analyze, and optimize how a system uses resources, such as energy, fuel, power, materials, or time.
Consumption pattern – It refers to the systematic tracking, modelling, and analysis of how resources (such as electrical power, fuel, water, or raw materials) are used over time and space.
Consumption point – It refers to a specific physical location, node, or terminal where a resource (such as water, electricity, gas, or freight / materials) is drawn, utilized, or converted.
Contact adhesive – It is an adhesive which is apparently dry to the touch and which adheres to itself simultaneously upon contact. An adhesive applied to both adherends and allowed to become dry, which develops a bond when the adherends are brought together without sustained pressure. It is an elastomeric substance applied to both mating surfaces. It develops an immediate, high-strength bond upon physical contact and pressure after its solvent evaporates, needing no external clamping or long curing times.
Contact angle – It is the angle which is formed at the interface between a liquid and a solid surface, specifically at the point where the liquid, solid, and gas (or vapor) meet. It is measured through the liquid phase, as the angle between the tangent line at the three-phase boundary and the solid surface. Essentially, it is a measure of how well a liquid ‘wets’ a solid surface. In lubrication, it is the angle at which the surface of a liquid drop meets the surface of a solid on which it is placed. In a bearing it is the angle between a diametral plane perpendicular to a ball-bearing axis and a line drawn between points of tangency of the balls to the inner and outer rings.
Contact angle hysteresis – It is the difference between the advancing contact angle (theta A) and the receding contact angle (theta R) of a liquid droplet on a solid surface, arising from molecular interactions and surface irregularities. It serves as a criterion for dynamic hydrophobicity on hydrophobic surfaces.
Contact angle measurement – It is the quantitative assessment of how a liquid wets a solid surface, defined geometrically as the angle formed at the three-phase boundary where a liquid, gas (or vapour), and solid intersect.
Contact angle technique – It is a conventional method used to identify the hydrophobicity of material surfaces by measuring the angle formed between a liquid droplet and the solid surface. It provides insights into the wetting properties of materials, with higher contact angles indicating higher hydrophobicity.
Contact-angle test – It measures the angle formed at the three-phase boundary where a liquid droplet, a solid surface, and a surrounding gas (or vapour / immiscible liquid) meet. This test quantifies the wettability of a solid surface and provides key insights into its surface energy, cleanliness, and coating adhesion.
Contact arc metal cutting (CAMC) process – It is a thermal-electric separation process which melts and removes metal using a discontinuous, high-current short-circuit arc created by momentary electrical contact between a non-consuming electrode and the work-piece, with the molten debris flushed away by high-pressure water jets.
Contact bearings – These bearings have mechanical contact between elements, and they include sliding, rolling, and flexural bearings. Mechanical contact means that stiffness normal to the direction of motion can be very high, but wear or fatigue can limit their life. Contact bearings are classified under two main categories namely (i) plain or sliding bearing and (ii) rolling bearing.
Contact bonding – It refers to a joining technique where both surfaces are coated with an adhesive (typically a contact cement or elastomer-based adhesive), allowed to dry or tack up completely, and then pressed firmly together to form an immediate, high-strength bond upon physical contact.
Contact cement – It is a high-strength, solvent-based or water-based synthetic elastomer applied to both mating surfaces. It develops an instant, permanent bond upon contact once the carrier liquid fully evaporates and the components are pressed together under pressure, needing no prolonged clamping.
Contact circle – It is the circular area of deformation and surface interaction which forms when a curved body (such as a sphere or a rounded roller) presses against another surface or body.
Contact condenser (- It is also called direct-contact condenser. It is a heat exchanger where the cooling liquid and the vapour (such as exhaust steam) mix directly together to cause rapid condensation. Unlike surface condensers, where a physical wall or tube separates the cooling water from the process fluid, a contact condenser allows both fluids to blend into a single stream.
Contact conductance – It refers to the ability of a contact interface, such as between a work-piece and a backing plate, to conduct heat, which can be quantified by parameters that represent the thermal conductance under different conditions, influenced by pressure and indentation effects.
Contact corrosion – It is a term primarily used in Europe to describe galvanic corrosion between dissimilar metals.
Contact dynamics – It is the study of how physical bodies interact, collide, slide, or press against each other when they come into contact, and how those interactions affect the motion and forces of the system.
Contact evaporator – A direct-contact evaporator is a heat and mass transfer device where a liquid phase is vapourized by the direct injection or mixing of a hot gas, superheated steam, or an immiscible hot liquid directly into the process fluid. Unlike traditional (indirect) evaporators, where a solid wall or heat exchanger tube separates the heating medium from the liquid, direct-contact systems supply latent heat directly at the fluid interface.
Contact extensometer – It is a device which physically attaches to a test sample to measure strain, length changes, and deformation under load.
Contact fat – It is the cracking and subsequent pitting of a surface subjected to alternating Hertzian stresses such as those produced under rolling contact or combined rolling and sliding. The phenomenon of contact fatigue is encountered very frequently in rolling-element bearings or in gears, where the surface stresses are high because of the concentrated loads and are repeated several times during normal operation.
Contact fatigue resistance – It is a material’s ability to withstand repeated cycles of high localized contact stress, such as rolling or sliding friction, without forming surface pits, cracks, or spalls. This type of fatigue happens when curved metal surfaces press together repeatedly, like in ball bearings, gears, and steel train rails.
Contact filter – It is a set of conditions or rules used to sort, search, or segment a list of people (contacts) based on specific attributes or actions. Contact filter is also the attenuation effect on roughness with wave-lengths shorter than the contact patch length between a wheel and rail, where the roughness profiles of the surfaces are averaged out because of their incoherent nature. This effect influences the excitation of the wheel / rail system by modifying the response to surface irregularities based on their spatial characteristics.
Contact filtration – It is a water treatment process where chemical coagulants or precipitants are injected directly into a pipe system just before the water reaches a filter bed, allowing flocs to form, coagulate, and become trapped within the filter media itself without needing a separate flocculation or sedimentation basin.
Contact force – It is a force which that occurs when two physical objects directly touch each other.
Contact force history – It refers to the variation of contact force over time during a dynamic impact event, which is influenced by the local indentation in the contact region between an impactor and a target. Accurate prediction of this history needs consideration of the indentation and the contact law governing the relationship between force and indentation.
Contact hypothesis – It refers to the theory that intergroup contact, under specific conditions such as equal status and cooperation, can lead to reduced prejudice between groups. This process can involve phases of de-categorization, harmonious differentiation, and recategorization to foster positive relationships.
Contacting asperity – It is an individual microscopic bump, peak, or protrusion on a solid surface which physically touches another surface when the two are pressed together.
Contacting ring seal – It is a type of circumferential seal which utilizes a ring spring-loaded radially against a shaft. The ring is either gapped or segmented, in order to have radial flexibility. The seal has overlapping joints for blocking leakage at the gaps. An axial spring load seats the ring against the wall of its containing cartridge.
Contacting seal – It is a sealing device which physically touches a moving or rotating shaft / surface to create a barrier against fluids, gases, or contaminants.
Contact length – It is the physical distance or arc over which two interacting surfaces, components, or tools touch and transfer loads, heat, or motion.
Contact lubrication – It is a little-used term relating to the conditions of lubrication obtained with solid lubricant powders rubbed into a surface. This term is normally not to be used.
Contact mechanics – it is the study of the mechanical interactions which occur when two bodies come into contact, involving the analysis of contact stresses, contact area, and the methods used for their measurement and prediction. It is important in engineering applications.
Contact model – It is a mathematical or computational framework which simulates how two or more independent surfaces interact, transfer forces, and deform when they touch. It prevents physical bodies from unrealistically passing through one another while calculating localized pressure distributions and friction at the interface.
Contact moulding – It is a process for moulding reinforced plastics in which reinforcement and resin are placed on a mould. Cure is either at room temperature using a catalyst-promoter system or by heating in an oven, without additional pressure.
Contactor – It is an electrically controlled, heavy-duty switch used to open or close a high-power electrical circuit. It functions like a large, industrial relay, allowing a low-voltage or low-current control signal (such as from a thermostat, programmable logic controller, or push button) to safely switch a high-current load.
Contact patch – It is the area of mutual contact when two bodies pressed together with a constant, or monotonically increasing, force, for example, in a standard hardness test using a diamond indenter. It is also the small area of a tyre’s tread which physically touches the road surface at any given moment. It is the sole mechanical connection between a vehicle and the ground, responsible for transferring all longitudinal (acceleration and braking), lateral (cornering), and vertical forces.
Contact plating – It is a metal plating process wherein the plating current is provided by galvanic action between the work metal and a second metal, without the use of an external source of current.
Contact potential – In corrosion technology, it is the potential difference at the junction of two dissimilar substances.
Contact pressure – It is the compressive force per unit area which develops at the interface where two solid bodies, surfaces, or a structure and a foundation touch each other.
Contact pressure moulding – It is a method of moulding or laminating in which the pressure, normally less than 70 kPa, is only slightly more than necessary to hold the materials together during the moulding operation.
Contact pressure resins – These are liquid resins which thicken or polymerize on heating, and, when used for bonding laminates, need little or no pressure.
Contact printing – It is a pattern-transfer or material-deposition method where a master template, stamp, or stencil makes direct physical contact with a substrate. This technique is widely used across micro-fabrication, electronics assembly, and nano-technology to replicate precise features.
Contact probability – It is the probability that a random micro-asperity peak on one surface is going to physically touch or deform against an opposing surface given a specific normal load and separation distance.
Contact pyrometry – It involves using temperature-sensing devices which make physical contact with a material, such as thermocouples immersed in molten metal, to reach thermal equilibrium.
Contact ratio – It is the average number of tooth pairs simultaneously in contact during the meshing cycle of gear teeth.
Contact resistance – In resistance welding, it is the resistance to the flow of electric current between two work-pieces or an electrode and a work-piece. It is also the electrical resistance between two contacting bodies, which is the sum of the constriction resistance and the film resistance.
Contact seal – It is a mechanical sealing device which forms a direct physical touch or sliding interface between a sealing element (such as an elastomer lip or carbon face) and a moving or stationary surface to block fluids, gases, or contaminants.
Contact simulation – It is the numerical procedure which ensures the forming material remains on the die without penetrating it, incorporating frictional effects to model the tangential movement of the material relative to the die surface. It involves challenges in simulating interactions because of the variable coefficients of friction and the complexities introduced by die surface geometries. It is also the numerical procedure used in computer-aided engineering (CAE) and finite element analysis (FEA) to model and predict how two or more distinct solid bodies interact, transfer forces, and deform when their surfaces touch or come close to each other.
Contact solar cells – These cells refer to electrical conductors attached to photo-voltaic (PV) cells which collect electrons and holes generated in the photo-voltaic material when exposed to photons, hence completing the circuit and enabling electric current flow from the cell to a load.
Contact stiffness – It is the quantity of force or load needed to produce a unit displacement (deformation) at the interface where two solid bodies touch. It measures a surface’s resistance to local elastic or micro-deformation when pressed against another object.
Contact stress – It is the stress which results near the surfaces of two contacting solid bodies when they are placed against one another under a non-zero normal force. This term is not sufficiently precise since it does not indicate the type of stress, although common usage normally implies elastic or Hertz stress. Contact (Hertzian) stress is the pressure at a contact between two solid bodies calculated as per the Hertz’s equations for elastic deformation. The theoretical area of contact between two non-conforming surfaces is frequently quite small. The interaction between these surfaces is frequently described as either point or line contact. Common examples of point contact are mating helical gears, cams and crowned followers, ball bearings and their races, and train wheels and rails. If the mating parts can be considered semi-infinite and if material behaviour is linearly elastic, then the local stress state can be described by Hertzian theory, as long as the contacting surfaces can be modeled as quadratic functions of those spatial coordinates defining the surfaces. Even in the absence of friction, the resulting three-dimensional stress state is quite complex, and although the local stress state is compressive, that is, the principal stresses beneath the load are negative, large subsurface shear stresses, which can serve as crack initiation sites, exist beneath the load.
Contact stress distribution – It refers to how compressive force is spread out across the localized interface area when two solid bodies are pressed together. It is the variation of contact pressure p(x) at the boundary where two curved or flat surfaces meet under an external load.
Contact surface defects – These refer to two-dimensional irregularities, damage, or discontinuities located on the outer boundary or interface of a metal component. These flaws disrupt the uniform geometry, crystal lattice structure, or smooth finish of the material. They can act as high-stress concentration points, leading to cracks, premature mechanical failure, or poor coating adhesion.
Contact surface length – It refers to the dimension or extent of the region where two or more physical bodies, mechanical components, or material surfaces meet and transmit loads, forces, or friction. In case of a vehicle, It refers to the length of the tyre’s contact area with the ground, which decreases with an increase in tyre pressure, affecting the lateral force generated during cornering.
Contact tank – It is a specialized vessel or basin designed to hold water, wastewater, or process fluids for a controlled period so that a chemical (such as chlorine, ozone, or coagulants) can mix and react completely.
Contact temperature – It refers to the temperature measured by a sensor or probe which is in direct physical contact with a medium, surface, or fluid.
Contact temperature measurement – It is a method where a physical sensor or probe makes direct thermal contact with a fluid, surface, or material to record its temperature mainly through heat conduction.
Contact thermal resistance – Thermal contact resistance is the temperature drop occurring between two contacting solids, quantified by the equation ‘Rc = (T1 – T2) / Q’, where ‘T1’ and ‘T2’ are the temperatures of the surfaces in contact and ‘Q’ is the heat flow. This resistance can increase when coatings or interstitial materials are present at the interface.
Contact time between the part and the lubricant – These refers to the exact duration during which a metal work-piece or powder compact remains in physical contact with a lubricating medium during shaping, compaction, or thermal processing. This duration governs critical phenomena like friction reduction, heat transfer, tool wear, chemical tribo-film formation, or lubricant removal.
Contact time under pressure – It refers to the total duration for which a metal work-piece or metal powder remains subjected to an applied compressive force while in physical contact with tooling, dies, or an adjacent surface. This parameter dictates how heat, electrical current, or mechanical deformation is transferred through the metal.
Contact transducer – It is a specialized device, very frequently used in non-destructive testing (NDT) and ultrasonic inspection, which makes direct physical contact with the surface of a test material to transmit or receive acoustic or mechanical energy.
Contact tube – It is a device which transfers current to a continuous electrode.
Contact type instruments – In contact type instruments, the sensing element of the instrument contacts the control medium for the measurements. Example is mercury in the glass thermometer.
Contact voltage – It is also called touch voltage. It is the potential difference which appears between an energized conductive surface (such as a faulted equipment casing) and the local ground or another touchable surface when an electrical fault occurs. It is the voltage experienced by a person or animal that simultaneously touches a faulted electrical structure and the earth or an earthed metal part.
Contact zone – It is the interface or area where two or more separate bodies or components meet, touch, or interact during a simulation or physical process. It is an area in which the force between the head and the surface is repellant.
Contained platform – It is frequently referred to as a self-contained platform. It is an independent, bundled system or environment which houses all necessary hardware, software, resources, or operational tools within itself, without needing external dependencies to function or execute its core purpose.
Container – It is the chamber into which an ingot or billet is inserted prior to extrusion. The container for backward extrusion of cups or cans is sometimes called a die. In shipping, a container is a standardized, secure box, typically made of steel, used for transporting goods across different modes of transport (ships, trains, trucks) without unloading and reloading. These containers, also known as shipping containers or intermodal freight containers, are designed for intermodal transport, meaning they can be moved between different transportation methods, making international trade and logistics more efficient.
Container and packaging industry – It consists of organizations which convert raw materials like plastic, metal, paper, and glass into finished or semi-finished products used to enclose, protect, and market goods.
Container cooling – It is frequently contextually tied to extrusion container cooling or crucible / mould container cooling. It refers to the controlled extraction of heat from the massive structural housing, the container, used to hold, shape, or compress metal during high-temperature manufacturing processes like extrusion, casting, or powder metallurgy. Its main purpose is to regulate the thermal gradient across the tool steel assembly, preventing overheating, thermal fatigue, or structural deformation of the equipment while simultaneously managing the microstructural cooling rate of the metal being processed.
Container liner – It is a replaceable, high-strength inner sleeve positioned inside the main chamber (the container) of a hot metal extrusion press. Its main function is to house, support, and direct a heated metal billet as a hydraulic ram forces the metal through a die to create custom shapes or profiles. Since it comes into direct contact with raw metals at extreme temperatures and intense frictional pressures, it acts as a sacrificial, high-durability barrier protecting the much heavier and costlier outer container assembly.
Container material – It specifies the exact physical, chemical, and mechanical properties of the substance used to build a storage or transport vessel. Choosing the right material ensures the container can safely hold its contents under specific conditions (like pressure, temperature, and corrosion) without failing.
Container ship – It is a specialized merchant vessel designed to transport freight packed into standardized, intermodal ISO (International Organization for Standardization) containers.
Container wagons – These are special flat wagons which are designed for handling containers.
Container wall – It refers to the vertical corrugated or flat panels (typically made of Corten steel, aluminum, or plywood-glass reinforced plastic) which enclose a shipping or storage unit. Unlike conventional buildings where walls act as main load-bearing supports, ISO (International Organization for Standardization)-standard shipping container walls mainly serve as a weather-proof envelope, a spatial enclosure, and a shear / stiffness contributor.
Containment – It is the act, process, or means to keep the parameters within the prescribed limits.
Containment area – During the construction of a facility designed to house radioactive materials, a series of containment barriers is put up between the materials inside and the environment outside the facility during construction. This creates separate areas called containment areas.
Containment concept – It is a barrier, or a set of barriers, which effectively limits the physical release of radio-nuclides to the environment, particularly in the context of nuclear power plants. It encompasses several containment types designed to ensure safety and minimize radiation leakage during design-basis accidents.
Containment function – It is the role of a physical barrier, structure, or system designed to confine a hazardous substance, energy, or condition within a defined boundary and prevent or minimize its uncontrolled release into the environment, work-place, or surrounding equipment.
Containment incidents – These incidents refer to events where there is a failure in maintaining continuous process containment, leading to the release of hazardous materials. These incidents create distractions which can increase operational dangers and highlight the importance of prevention and effective incident response.
Containment structure – It is a gas-tight, high-strength shell, typically made of steel-reinforced or pre-stressed concrete with a steel liner, which encloses a nuclear reactor and its main coolant system.
Containment vessel – It is a leak-tight, high-strength structural enclosure designed to hold hazardous materials, pressurized gases, radioactive by-products, or high-energy explosions, preventing their release into the public environment.
Contaminant – It is an impurity or foreign substance present in a material or environment which affects one or more properties of the material.
Contaminant concentration – It is the quantity of an unwanted chemical, physical, biological, or radiological substance present within a specific volume or mass of a host medium (such as air, water, soil, or a manufacturing process stream).
Contaminant dispersion – It is the process by which dissolved, suspended, or airborne pollutants spread out as they move through an environment (such as air, water, or porous soil / groundwater). Contaminant dispersion is normally driven by the combination of three main physical processes namely advection, molecular diffusion, and mechanical (hydrodynamic) dispersion.
Contaminant emission – It refers to the mass flow, rate, or volume of unwanted, harmful, or hazardous substances (such as gases, volatile organic compounds, fumes, oil mists, or particulate matter) released from a specific industrial process, equipment, or source into an immediate workspace, enclosure, or the ambient environment.
Contaminant generation – It refers to the rate or quantity of unwanted harmful substances, such as fumes, oil mists, volatile organic compounds (VOCs), gases, dust, or particulates, produced by a specific physical, chemical, or industrial process.
Contaminant level – It is a relative measure of how much of a contaminant is present. Contaminant levels are expressed in concentrations such as parts per million (ppm), parts per billion (ppb), milligrams per litre, or micrograms per litre.
Contaminant movement – It is frequently called contaminant transport. It is the physical, chemical, and biological process by which pollutants migrate, spread, retain, and transform through environmental or engineered media such as soil, groundwater, surface water, or air. Civil, geoenvironmental, and environmental engineers study these mechanisms to predict how pollution moves from a source, design protective systems like landfills, and plan groundwater or site remediation.
Contaminant removal – It refers to the systematic process of identifying, isolating, reducing, or completely eliminating unwanted solid, liquid, gaseous, biological, or chemical substances from fluids, surfaces, or structural environments to meet safety, quality, or performance standards.
Contaminant removal effectiveness (Epc) – It is the ratio of the contaminant concentration in the exhaust air to the contaminant concentration at a specific point or zone in the occupied space. Epc = Ce / Cp’, where ‘Ce’ is the contaminant concentration in the exhaust air, and Cp is the contaminant concentration at a point in the occupied space (or breathing zone).
Contaminant removal efficiency – It is a standard metric which measures how well a treatment process, filter, or ventilation system removes unwanted substances from a fluid (such as water, wastewater, or air). In general mass-balance or treatment units (like water purification or wastewater plants), removal efficiency (E) is expressed as a percentage or fraction E = [(Cin – Cout) /Cin] x100 %’, where ‘Cin’ is the concentration or mass of the contaminant entering the system., and ‘Cout’ is the concentration or mass of the contaminant leaving the system (after treatment).
Contaminant source – It is an origin, such as equipment, processes, materials, or site features, which releases hazardous or unwanted substances into the environment, air, soil, or ground-water.
Contaminated condition – It is the state in which unwanted substances, particles, energy forms, or biological agents are introduced into a material, system, or environment in quantities which degrade performance, compromise safety, or violate design and regulatory limits.
Contaminated land – It refers to ground affected by hazardous substances, industrial chemicals, or waste materials at concentrations which pose a risk to human health, property, infrastructure, or the environment, needing specific technical or engineering interventions.
Contaminated water – It is the water which gets contaminated with dissolved minerals and suspended solid particles after its use.
Contaminating noise – It refers to external sounds which interfere with audio evaluations, such as conversations, equipment noise, or environmental disturbances, which can compromise the quality of testing in a quiet room setting.
Contamination – Contamination is the presence of a constituent, impurity, or some other undesirable element that renders something unsuitable, unfit or harmful for physical body, natural environment, and workplace etc. In case of nucleal facility, it is the radioactive material which is deposited on the surface of or inside structures, areas, objects, or people.
Contamination factor – It is a quantitative metric used to evaluate the degree of pollution or the impact of unwanted particles and substances in a specific system. Depending on the engineering discipline, it is the ratio of the measured concentration of a specific contaminant (usually a heavy metal) in a sample (such as soil, sediment, or water) to its pre-industrial or natural background concentration. ‘Cf = Cmetal / Cbackground’, where ’Cmetal’ is the concentration in the sample and ‘Cbackground’ is the baseline or reference value).
Contamination, quenchant – Quenchant contamination is the introduction of foreign substances into a heat-treating liquid which degrades its cooling performance and compromises metal properties.
Content dependence – It refers to how a material’s physical, mechanical, or chemical properties (such as elasticity, hardness, or strength) change based on the concentration or presence of a specific element, solute, or chemical compound embedded within it. It refers to the relationship between a material’s properties, such as elastic modulus or hardness, and the concentration of a specific element or compound within that material, as demonstrated by the effects of hydrogen content on zirconium hydride and deuteride.
Content engineering – It is the discipline of designing, building, and managing the technical and structural systems, such as work-flows, meta-data, templates, and automation pipelines, which allow organizations to produce and distribute content at scale.
Contention – It refers to the competition among multiple users to access the same communication medium, needing an algorithm to determine which user has the right to transmit data. In wireless networks, contention is managed through protocols that implement random backoff delays to minimize packet collisions during data transmission.
Contention ratio – It is the ratio of the potential maximum demand to the actual available bandwidth on a shared network segment. It counts how many users, devices, or network premises share a single pool of fixed data capacity or backhaul.
Contention window – It is an integer range of time slots, bounded by a minimum value (CWmin) and a maximum value (CWmax), from which a network device randomly picks a backoff counter before transmitting data on a shared channel. It is a core component of the CSMA/CA (carrier sense multiple access with collision avoidance) random-access mechanism used in wireless protocols like Institute of Electrical and Electronics Engineers standard IEEE 802.11 Wi-Fi. A contention window in computer networking refers to a time period set after a frame transmission to prevent collisions among stations contending for channel access. It helps differentiate between high and low-priority services by assigning shorter windows to higher priority stations.
Content knowledge – It refers to the information and expertise related to requirements, architecture design decisions, and rationale in software development. It encompasses the core architectural knowledge necessary for developing software systems. It refers to an educator’s or professional’s detailed, domain-specific understanding of engineering facts, concepts, theories, principles, and core technical skills.
Content perspective – It is a cross-category grouping or viewpoint used to organize, filter, and deliver information based on who is interested in it or what role they hold.
Content request – It is the strategic process of designing, structuring, and refining formal specifications (or tickets) for content which needs to be created. It is a client-initiated demand for a specific content, which is handled by the closest node in a set of nodes which have either the original or replicated content. If the initial node cannot fulfill the request, it can be forwarded to another node in the set, and the request fails if no nodes are available to forward it.
Content transfer – It is the process of moving digital materials, files, or information from one system, environment, or platform to another.
Context – It describes and represents the ‘known world’ of a system, mapping out all relevant environmental factors, user details, tasks, physical locations, and constraints that influence how a system behaves.
Context approach – It is an educational and cognitive framework where knowledge is learned, structured, and applied through specific, real-world scenarios rather than as abstract, isolated facts.
Context-aware services – These services refer to systems which integrate knowledge from environmental and situational contexts to improve user interaction, allowing for intelligent, task-oriented responses based on user actions, states, and goals. These services aim to provide improved usability by adapting to the user’s context and preferences.
Context-aware systems – These are the systems which utilize contextual information to provide relevant information and services to users, adapting their operations based on the user’s task and environmental situation. These systems typically involve context acquisition, processing, and acting to tailor responses to the user’s current context.
Context definition – It is the description and representation of the ‘known world’ of a system, encompassing the relevant contextual information which characterizes the situation of an entity involved in user-application interactions. It includes aspects such as the user, their tasks, location, time, and relationships, which are necessary for context-aware systems to adapt their behaviour accordingly.
Context engineering – It is the technical discipline of designing, structuring, and optimizing the entire information environment provided to a large language model (LLM) or AI (artificial intelligence) agent at runtime.
Context model – It is an abstraction of a situation context used to structure, identify, analyze, and synthesize that situation. It evolves as the understanding of the situation improves and serves as a basis for interpreting and visualizing information about the situation.
Context modelling – It is the practice of formally representing and structuring situational information about an environment, system, or process. It defines how context data, such as users, hardware, software, physical locations, and relationships, are captured, organized, and maintained so a system can interpret them and act upon them.
Context switch – It is an operation where a central processing unit (CPU) suspends a currently running process or thread, saves its state (registers, program counter, and central processing unit status) into a data structure called a process control block (PCB), and loads the saved state of the next scheduled process or thread. Context switch is also the cognitive and mental shift needed when a developer stops working on one task, project, or stream of communication and moves to a completely different one (such as jumping from writing code to a sudden slack message, a meeting, or a code review).
Contiguous allocation – It is a method of space allocation for a file where storage is assigned as a set of consecutive sectors, allowing for quick access and retrieval of records due to minimized movement of read / write heads.
Contiguous fluid – It is an idealization which models a fluid as an unbroken, continuous distribution of matter with no internal microscopic voids or gaps, allowing macroscopic properties like density, pressure, and velocity to be treated as smooth, differentiable functions of space.
Contiguous spectrum – It refers to a range of frequency bands which are adjacent to one another, allowing for the deployment of multiple component carriers with optimized guard bands to improve spectrum utilization and performance.
Continental crust – It is the thick, outermost solid layer of the earth that forms the continents and shallow continental shelves. It represents the foundational geologic medium for large-scale civil infrastructure, deep foundations, tunneling, seismic design, and resource extraction.
Continental drift – It is the large-scale horizontal movement of earth’s continental landmasses relative to one another and ocean basins over geologic time, a concept originally proposed by Alfred Wegener in 1912 and now explained and subsumed by modern plate tectonics. Continental drift itself is too slow (averaging around 1.5 centimeters per year to 2.5 centimeters per year) to directly impact short-term structural design loads. However, the underlying mechanical processes, plate tectonics, crustal stress accumulation, fault mechanics, and mantle dynamics, are critical for seismic hazard assessment, geodetic and GPS (global positioning system) monitoring, crustal stress fields, and geologic evolution.
Continental margin – It is the underwater edge of the continental crust. It forms the transition zone where the dry-land mass of a continent meets the deep ocean floor (abyssal plain). The continental margin is a critical boundary zone for offshore infrastructure, submarine pipelines, petroleum and mineral extraction, telecommunication cables, and slope-stability analysis.
Contingency – Risk and uncertainty is captured in the project cost estimate as contingency. Contingency amounts are revised with each new cost estimate over the project’s life cycle as the risks are revealed and uncertainty is reduced. Hence project cost estimate during plant feasibility stage has higher component of contingency as compared with the project cost estimates made during construction and commissioning stage.
Contingency factor – It is an extra safety allowance, percentage, or financial reserve added to designs, lifting calculations, or project budgets to cover unknown variables, minor errors, or unexpected site conditions.
Contingency plan – It is a pre-defined alternative course of action designed to restore systems, maintain safety, or keep a project on track if an unexpected failure or disruptive event occurs.
Contingency planning – Contingency planning provides protection against the unforeseen threats. It covers failures of critical systems, equipment, automated processes, energy, communications, suppliers, personnel, and natural calamities. It consists of the actions taken by the organization to prepare the organization for an impending emergency.
Contingency procedure = It is a documented, pre-planned sequence of technical actions and fail-safe responses executed when a system, process, or infrastructure experiences an unexpected failure, disturbance, or threshold breach. It is a structured ‘plan-B’ which establishes clear operational steps, decision triggers, and resource allocations to safely transition or recover a system when normal operating assumptions fail.
Contingency reserve – It is an allocation of time or money (or both) set aside for the occurrence of known possibilities which can delay a project or make it more expensive. It is not the same as a management reserve, which is an allocation made for unforeseeable circumstances. Use of a contingency reserve is typically authorized upon the occurrence of a contingency.
Continual improvement – It is a systematic, ongoing effort to optimize products, services, processes, or quality management systems through both incremental steps and breakthrough changes. It combines corrective and preventive actions to address non-conformities and improve performance.
Continued operation – It refers to the ongoing maintenance, certification, and sustained functional readiness of equipment, systems, or assets to ensure they remain safe, compliant, and operational over time.
Continued surveillance – It is the ongoing, systematic monitoring, inspection, or observation of a system, structure, or operational process at specified or random intervals to ensure performance, compliance, and the absence of adverse outcomes.
Continue operator – It is a control flow structure in programming and engineering languages which skips the remaining statements of the current loop iteration and immediately jumps to the next iteration. It bypasses execution of the rest of the code block inside a loop when a specific condition is met, without terminating the entire loop.
Continuity – It refers to an unbroken, smooth physical state or mathematical function without gaps, breaks, or sudden jumps.
Continuity bond – It is a metallic connection which provides electrical continuity between metals structures.
Continuity condition – In structural mechanics (such as the double integration method for beams), a continuity condition is a mathematical requirement which ensures smooth and uninterrupted transitions in deflection and slope (rotation) across different segments of a structural member.
Continuity equation – It is a mathematical representation of the law of conservation of mass for a gas, stating that the mass flow rate remains constant within a fluid system. It can be expressed as ‘m = d x A x V’, where ‘m’ is the mass flow rate, ‘d’ is the fluid density, ‘A’ is the cross-sectional area, and ‘V’ is the gas velocity. In fluid mechanics, the continuity equation shows that mass is neither created nor destroyed in a fluid flow. In electromagnetic theory, the continuity equation represents local charge conservation.
Continuity of coating – It is the degree to which a porcelain enamel or ceramic coating is free of defects, such as bare spots, boiling, blisters, or copper-heads, which can reduce its protective properties.
Continuity of operations – It refers to the capability of an organization or technical system to maintain essential functions and reliable data flow during and after a disruptive event.
Continuity point – It refers to a location in a physical system or mathematical model where a field variable (such as pressure, velocity, stress, strain, voltage, or current) transitions smoothly without sudden jumps, breaks, or infinite spikes.
Continuity principle – It states that mass cannot be created or destroyed within a steady, flowing fluid system. What flows into a control volume is to be equal what flows out, accounting for any accumulation inside.
Continuous – It means a process, system, or function which operates, flows, or changes smoothly and without interruption over time or space.
Continuous annealing – Continuous annealing of sheet involves the rapid passage of uncoiled sheet through heating and cooling equipment. During continuous annealing, uncoiled steel sheet is passed through a two-stage furnace for times on the order of a few minutes. The first stage heats the steel and accomplishes recrystallization, while the second stage heats at a lower temperature to overage the steel and remove carbon from the solution effectively. Without this step, the thin sheet cools very rapidly and retain carbon in solution. This carbon eventually causes strain or quench aging and reduces sheet formability. The rapid cooling and in-line over-aging also enables the production of sheet steels for very demanding automotive and appliance applications. The metallurgical advantages of continuous annealing over conventional batch annealing include improved product uniformity, surface cleanliness and shape, and the versatility to produce a wide range of steel grades.
Continuous annealing furnace – It is an automated industrial heating system where metal strips or parts move non-stop through sequential temperature-controlled zones. This process softens the metal, relieves internal stress, and improves ductility with uniform precision.
Continuous beam – It is a structural member which extends continuously across three or more supports without any internal joints or hinges. Since it has more support reactions than available static equilibrium equations, engineers cannot solve for internal forces using simple static equations alone. They are to use advanced methods.
Continuous beam analysis – It is the structural engineering process of finding the internal forces, reactions, and deformations of this type of beam under external loads.
Continuous blow-down – It is the uninterrupted removal of concentrated boiler water from a boiler to control total solids concentration in the remaining water.
Continuous casting – It is a casting technique in which a cast shape is continuously withdrawn through the bottom of the mould as it solidifies, so that its length is not determined by mould dimensions. It is used mainly to produce semi-finished products such as billets, blooms, ingots, slabs, and strip.
Continuous casting by twin-roll method – It is a near-net-shape manufacturing process which combines casting and hot rolling into a single step to turn molten metal directly into a thin, continuous solid strip.
Continuous casting machine – It is the machine in which continuous casting process is carried out. It links steelmaking with hot rolling of steel. In this machine, the liquid steel is solidified into a semi-finished steel product for subsequent rolling in the hot rolling mill. The basic operation of the machine is to convert liquid steel of a given composition into a strand of desired shape and size through a group of operations. Continuous casting machines are identified by the shape of the product they cast. Accordingly, these machines can be a billet casting machine, a bloom casting machine, a near net shape, beam blank, or dog bone casting machine, a round casting machine, a slab casting machine, a thin slab casting machine, or a strip casting machine.
Continuous casting mould – It is basically an open-ended box structure containing a water-cooled inner lining fabricated from a high purity copper alloy. The box can come in many shapes and sizes in order to cast different semis such as blooms, billets, round beam blanks, slabs, and thin slabs. Continuous casting mould is regarded as the heart of the continuous casting process and plays a very important role in the efficiency of the process and the strand quality. It is in the mould that the final cast shape and the strand surface quality are produced. If the conditions are not correct in the mould, then the strand quality cannot be corrected later. Once in the mould, the liquid steel freezes against the walls of the water-cooled copper mould to form a solid shell.
Continuous casting mould powders – These powders are used primarily to facilitate the passage of liquid steel through the mould of the continuous casting machine. It is also known by several other names such as mould powder, casting powder, mould flux, mould flux slag, or mould flux powder. Mould powder plays an important role in the continuous casting of liquid steel and is one of the most influential and critical factors in the stability of the casting process and for the smooth casting of the liquid steel.
Continuous casting process – It is a method which transforms molten metal into solid form on a continuous basis, allowing for the efficient mass production of large volumes of semi-finished metal products in different shapes and sizes. This process maintains a steady state where molten metal solidifies against mould walls while being withdrawn at a constant rate, ensuring consistent quality.
Continuous conduction mode – It is an operating state in power electronics where the current flowing through an energy storage element, like an inductor or transformer, never drops to zero during the entire switching cycle.
Continuous conveyor – It is a machine and device used for long distance continuous conveying of loose material (such as sand) or items (such as castings) in foundry shop. The types of machines include belt conveyor, pan conveyor, vibrating conveyor, and overhead chain conveyor etc., excluding pneumatic conveyor for conveying clay, dry sand, sea-coal and other powder materials.
Continuous cooling – It refers to the process of lowering the temperature of a material at an uninterrupted, varying or constant rate from a high temperature down to room temperature without holding it at any intermediate temperature.
Continuous cooling curve – It is a graphical line plot of temperature against time which shows how a material’s temperature drops continuously at a specific rate, helping engineers track phase changes and microstructural transformations. Continuous cooling curves form the basis of ‘continuous cooling transformation’ (CCT) diagrams, which are widely used to design heat treatment processes like annealing, normalizing, and quenching.
Continuous cooling transformation – It is a thermal process where phase changes in a material (typically steel) occur dynamically as it cools down continuously.
Continuous cooling transformation (CCT) diagram – It is a set of curves drawn using logarithmic time and linear temperature as coordinates, which define, for each cooling curve of an alloy, the beginning and end of the transformation of the initial phase.
Continuous data – It is measurable data which can take any value within a certain range or interval, allowing for an infinite number of possibilities. It is a type of quantitative data which can be divided into smaller, independent components, unlike discrete data, which consists of specific values. Continuous data is measured rather than counted and can include fractions and decimals.
Continuous derivative – It means that a function is differentiable, and its resulting derivative function f'(x) is also continuous without any jumps, breaks, or infinite oscillations. Continuous derivatives are continuous within a certain neighborhood, ensuring that the function behaves smoothly without abrupt changes in slope.
Continuous desulphurization – It is an uninterrupted, steady-state chemical or physical process which removes sulphur compounds from fluid streams, fuels, or exhaust gases. It prevents equipment corrosion and limits toxic sulphur di-oxide (SO2) or hydrogen sulphide (H2S) emissions.
Continuous discharge elevators – In these elevators, V-type buckets are used without any gap between them. These elevators are employed for handling larger lumps and materials which can be difficult to handle by centrifugal discharge. The charging of the buckets is by direct filling. The discharge is by directed gravity i.e. when the buckets pass over head wheel, the flanged end of the preceding bucket act as a chute to deliver materials gently to the discharging spout. This type of charging and discharging is particularly effective for handling fragile materials. Both belt and chain are used as pulling medium. Speed is generally kept low. These elevators are used vertically or inclined. When inclined, special supports are provided for belt / chain in the return run, and wider casing is provided to allow for return run sag.
Continuous emission monitoring systems – These are systems which monitor the real-time concentration of different pollutants in emissions, such as mercury, and typically consist of a pre-treatment / conversion unit and an analysis unit.
Continuous engineering – It is an integrated approach which connects design, development, testing, and operations into a single iterative workflow to speed up product launches and adapt to real-time changes. Instead of traditional sequential steps, where testing and commissioning happen only at the very end, continuous engineering uses parallel activities, automation, and real-time data feedback across the entire life-cycle.
Continuous enrichment – It is the ongoing process of updating and refining knowledge within knowledge graphs (KG) to adapt to the evolving demands of different stakeholders, balancing the need for new knowledge with the maintenance of existing resources while ensuring the accuracy and quality of the information.
Continuous equal-channel angular extrusion – It is also known as equal-channel angular pressing (ECAP). It is a metalworking process that refines a material’s grain structure by pushing it through a bent die without changing its outer shape or cross-sectional area.
Continuous fibre – It is an unbroken reinforcing strand (such as carbon, glass, or aramid / Kevlar) which runs the full length of a composite part or spans across structural load paths without random breaks. Unlike chopped or short fibre (which measure under around 6 millimeters), continuous fibres have an indefinite or spool-level length, eliminating end-effect weaknesses under load.
Continuous fibre ceramic composite – It is a ceramic-matrix composite in which the reinforcing phase(s) consists of continuous filaments, fibres, yarn, or knitted or woven fabrics.
Continuous fibre reinforcement – It is the incorporation of continuous fibres into composite materials to considerably improve their mechanical properties, enabling the fabrication of complex structures with customizable architectures through advanced manufacturing processes.
Continuous fibre sheet – It is a structural material made of unbroken, full-length reinforcing fibres (such as carbon, glass, basalt, or aramid) embedded within a continuous polymer, ceramic, or metal matrix.
Continuous filament – It is an unbroken, indefinite-length fibre produced by extruding molten or solution polymers or natural materials (like silk) through a multi-hole spinneret. Unlike staple fibres (which consist of short, discrete pieces twisted together), continuous filaments run the entire length of the yarn or structure without loose ends.
Continuous filament yarn – It is the yarn formed by twisting two or more continuous filaments into a single, continuous strand.
Continuous filtration – It is a process where the separation of solids from a fluid (liquid or gas), feeding, washing, cake formation, and discharge all occur simultaneously and in a steady state without stopping the operation.
Continuous flight auger (CFA) piles – These piles are also referred to as auger-cast, auger-cast-in place, and auger-pressure grout piles. These piles are constructed by using continuous flight augers and by drilling to the final depth in one continuous process. When the drilling to the final depth is complete, the auger is gradually withdrawn as concrete or sand / cement grout is pumped into the hole through the hollow centre of the auger pipe to the base of the auger. Reinforcement, if needed, can be placed in these piles immediately after the withdrawal of the auger. The reinforcement is normally confined to the top 10 metres.
Continuous function – It is a function whose graph has no breaks, satisfying the conditions that it is defined at a point, the limit exists at that point, and the limit equals the functional value at that point.
Continuous furnaces – These furnaces move the charged material while it is being heated. Material passes either over a stationary hearth, or the hearth itself moves. If the hearth is stationary, the material is pushed or pulled over skids or rolls, or is moved through the furnace by woven wire belts or mechanical pushers. Except for delays, a continuous furnace operates at a constant heat input rate, burners being rarely shut off. A constantly moving (or frequently moving) conveyor or hearth eliminates the need to cool and reheat the furnace (as is the case with a batch furnace), thus saving energy.
Continuous galvanizing – Sheet, wire, and tube sections are galvanized using a continuous process associated with the manufacturing of the product. The galvanized coating is almost 100 % pure zinc and applied to a maximum thickness of about 30 micrometers.
Continuous gas-carburizing furnace – It is an industrial heat-treatment system designed to continuously move low-carbon steel parts through zoned, controlled-atmosphere chambers to infuse carbon into the metal surface.
Continuous girder – It is a single structural beam or girder which spans across three or more supports (such as abutments and intermediate piers) without any mechanical breaks or interruptions.
Continuous glass fibre – It is an engineering reinforcement material made of thousands of parallel, unbroken glass filaments drawn from molten silica-based glass and gathered into continuous strands, yarns, or rovings.
Continuous heating – It refers to thermal processes or systems where materials, fluids, or parts are heated in an uninterrupted, steady stream rather than in isolated batches.
Continuous heat treatment – It is an automated thermal processing method where metal parts move non-stop on a conveyor, mesh belt, or roller hearth through a tunnel-style furnace divided into distinct temperature and atmosphere zones.
Continuous improvement process – It is a means by which the organization creates and sustains a culture of continuous improvement. The organization deliberately seeks to create a positive and dynamic working environment, foster teamwork, apply quantitative methods and analytical techniques, and tap the creativity and ingenuity of its employees.
Continuous integration splice – It is a technique for seamlessly joining the ends of a conveyor belt without mechanical fasteners, demanding skilled installation and recurrent inspections.
Continuous lattice – It is a complete partially ordered set (poset) in which every element can be approximated as the least upper bound of the elements which are strictly ‘way below’ it. Continuous lattices play a central role in order theory, topology, and domain theory for computer science.
Continuous load – It is an electrical load where the maximum current is expected to continue for 3 hours or more.
Continuously operating system – It refers to a steady-state process / material flow system which processes or conveys materials without interruption, maintaining a steady-state flow rate over time. It is the direct opposite of a batch operating system, where materials are processed in discrete, separate lots or cycles. It is also a live-state architectural model (in software and systems engineering). It is an operational model or architecture where the system state is always live and current rather than relying on periodic data-base polls or manual refreshes.
Continuously reinforced concrete pavement – It is a type of rigid highway pavement which features continuous longitudinal steel reinforcement throughout its entire length and has no transverse contraction or expansion joints (except at structural interfaces like bridges, end-of-day construction headers, or transitions).
Continuously variable transmission – It is a mechanical or automatic transmission which can change steplessly through an infinite range of gear ratios between its minimum and maximum limits, unlike traditional gear-boxes which rely on a fixed set of discrete gear steps.
Continuously welded rail – It is a railway track system where individual steel rail lengths are welded together into seamless continuous strings which frequently extend for miles or entire station-to-station distances. It replaces traditional bolted joints and fishplates with smooth, molecular-level fusion welds (such as electric flash-butt or thermit welding).
Continuous machine – It refers to specialized production equipment designed to run non-stop, 24 hours a day, 7 days a week, processing materials in a constant, uninterrupted stream rather than in separate batches.
Continuous mandrel rolling process – It is a metalworking method used to manufacture seamless steel tubes and pipes. In this hot-rolling process, a heated solid cylindrical steel billet is first pierced to create a hollow shell, and then a long cylindrical bar, called a mandrel, is inserted inside it. The shell and mandrel together pass through a series of multi-axis rolling mills which continuously reduce the tube’s wall thickness and outside diameter while elongating its length.
Continuous manufacturing – It is an operational approach where raw materials flow in constantly at one end of a plant and finished products emerge continuously at the other (unlike batch processing, which makes products in separate, distinct lots).
Continuous measurement – It refers to a data-collection and monitoring process where every single instance or value of a target parameter is recorded and evaluated in real-time or across a full operational life-cycle, rather than relying on periodic sampling.
Continuous medium – It is also called continuum. It is an idealization which treats matter as a continuous distribution of mass with no empty spaces or voids, ignoring its discrete molecular or atomic structure.
Continuous mill – It is a production system where material flows in one direction through a series of synchronized, consecutive working stations, such as roll stands or grinding dies, undergoing uninterrupted processing from input to output.
Continuous miner – It is a sophisticated mining apparatus seamlessly integrating a conveyor system, demanding meticulous, recurrent maintenance for optimal operational efficiency.
Continuous mixer – It is a processing machine which simultaneously feeds, mixes, and discharges materials in an uninterrupted, steady stream. Unlike batch mixers which process discrete quantities one-by-one, raw ingredients are metered into the chamber at fixed flow rates and blended dynamically as they move toward the exit.
Continuous monitoring – It is the real-time, automated process of tracking, collecting, and analyzing data from IT (information technology) systems, software applications, and net-works to detect performance issues or security threats. Rather than relying on periodic manual checks, it provides persistent oversight to help teams find bugs, system failures, and vulnerabilities as they happen.
Continuous monitoring programme – It is a formal, ongoing strategy and automated process used to collect, analyze, and report data from an organization’s systems, networks, and applications in real time or near real time. It is a programme established to gather information using pre-established metrics and implemented security controls to track changes in an organization’s risk and compliance posture.
Continuous operation mode – It refers to a method in pressure-driven membrane processes where the solution to be processed is fed into a series of modules, producing permeate and concentrate streams after a single passage, typically used for large-scale production systems. This mode frequently uses recirculation loops to maintain optimal hydrodynamic and mass transfer conditions.
Continuous partial derivative – It refers to a partial derivative of a multivariable function whose resulting function values are continuous across a given domain, meaning the rate of change surface or field has no abrupt jumps, breaks, or singularities.
Continuous phase – In an alloy or portion of an alloy containing more than one phase, it is the phase which forms the matrix in which the other phase or phases are dispersed.
Continuous pour casting – It normally refers to counter pressure casting (CPC), or it specifically denotes the structural ‘continuous pouring’ technique used within specialized metallurgical processes like manufacturing composite steel mill rolls or large-scale civil engineering concrete casting. Very frequently in advanced metallurgy, CPC (counter pressure casting) is an advanced low-pressure die casting variant which uses a pressurized chamber to precisely regulate metal solidification. It also represents the continuous, uninterrupted feeding of molten material into a mould to eliminate seams, weak bonds, or crystallization defects.
Continuous pouring – It is the uninterrupted placement of fresh concrete into a formwork structure before any previously placed layer begins to set or harden.
Continuous pour process – It is the process in which a concrete pour in a tunnel is poured as a continuous operation.
Continuous precipitation – It is the precipitation from a super-saturated solid solution in which the precipitate particles grow by long range diffusion without recrystallization of the matrix. Continuous precipitates grow from nuclei distributed more or less uniformly throughout the matrix. They normally are randomly oriented, but can form a Widmanstatten structure. It is also called general precipitation.
Continuous process – It is a complex system with interconnected components which need efficient monitoring and control. It involves the extraction of valuable knowledge from a large quantity of real-time data generated by sensors and actuators, aiming to support online decision-making procedures.
Continuous processing – It is a manufacturing method where raw materials are fed into a system and finished products emerge in a steady, unbroken stream without interruption or batch separation.
Continuous profile – It is a data structure or mathematical representation which describes how a specific property or variable changes smoothly and uninterruptedly across a given dimension, such as time, space, distance, or depth. Unlike discrete profiles (which look like a series of separate data points or steps), a continuous profile provides an infinite number of values within its range, typically represented by a smooth curve or a mathematical function. Continuous profile in engineering combines a profile tolerance (such as profile of a surface or profile of a line) with a continuous feature (CF) symbol under geometric dimensioning and tolerancing (GD&T) standards.
Continuous programme – It is an operational framework where ideas, projects, or tasks flow continuously through a system rather than being processed in rigid, seasonal budget batches.
Continuous programme management – It is the ongoing, unbroken coordination of multiple related technology, product, or design initiatives which flow continuously through the organization rather than stopping for rigid, yearly budget cycles.
Continuous reactor – It is an open system where reactants are added continuously through an inlet and products are simultaneously withdrawn through an outlet at a steady-state. In a continuous reactor, the reaction chamber is separate from the material storage tank, so the reactor can operate continuously during heat storage and release. Solid reactants are transferred from the storage tank into the reactor, and then once the reaction is completed, solid products are transferred to another storage tank, which makes working in steady-state and storing a large quantity of heat through a relatively small reactor possible. However, continuous reactors mean material transportation, so mechanical parts are added and the cycle stability is also affected.
Continuous rolling – It is a multi-stage process where metal stock passes through multiple consecutive sets of rotating rolls (stands) in a single sequence to progressively reduce thickness and shape the material.
Continuous rolling mill – It is a rolling mill consisting of a number of strands of synchronized rolls (in tandem) in which metal undergoes successive reductions as it passes through the different strands.
Continuous rotary extrusion – It is also known as the Conform process. It is a continuous manufacturing method which uses frictional heat and rotational pressure to shape metal feedstock into long, unbroken profiles like wires, strips, and tubes.
Continuous rotary furnace – It is an industrial heating system featuring a slowly rotating, slightly inclined cylindrical drum or tube which continuously feeds, tumbles, and discharges bulk solids, granules, or powders for uniform thermal processing.
Continuous rotary hearth furnace – It is an industrial thermal processing system featuring a large, rotating circular floor (the hearth) enclosed within a stationary insulated shell which carries work-pieces through distinct temperature zones.
Continuous rotary hearth sintering furnace – It is an industrial thermal processing system featuring a circular, rotating floor (hearth) enclosed in a stationary chamber which uniformly heats and bonds compacted metal, ore fines, or ceramic powders (sintering) in an uninterrupted production cycle.
Continuous rotary hearth reduction furnace – It is an industrial thermal processing system featuring a slow-moving, donut-shaped rotating table enclosed in a stationary chamber designed to chemically reduce metal oxides into metallic form through high-temperature reactions.
Continuous sand mixer – It is a machine in which the sand with bonding agents are continuously mixed and conveyed to the discharge gate. Typically, the mixing takes place by screw-type mixing principles.
Continuous signal – It is a signal which can take any value within its range. Continuous signals are data or physical measurements (such as temperature, voltage, or pressure) which can take any value along a smooth continuum rather than discrete, stepped intervals.
Continuous sintering – It is pre-sintering, or sintering, in such manner that the objects are advanced through the furnace at a fixed rate by manual or mechanical means.
Continuous solid solution – It is a single-phase alloy where two elements are completely soluble in each other in both liquid and solid states across all proportions (0 % to 100 %).
Continuous spectrum – It is an unbroken band of colours which transitions smoothly from one wave-length to another, indicating that all wave-lengths between the extremes are present. It is typically emitted by a heated body, with the specific wave-lengths depending solely on the temperature of the body rather than its material composition. In X-rays, continuous spectrum is the poly-chromatic radiation emitted by the target of an X-ray tube. It contains all wave-lengths above a certain minimum value, which is known as the short wave-length limit.
Continuous speech recognition – It is the process of converting natural, unbroken spoken language into text or commands without requiring the speaker to pause between words. Unlike isolated word recognition, which needs distinct pauses, continuous speech recognition (CSR) processes continuous audio streams and handles natural conversational flow.
Continuous steam injection – It is a thermal enhanced oil recovery (EOR) process where a two-phase mixture of steam and water is continuously pumped into dedicated injection wells to heat underground heavy oil or bitumen reservoirs. This method has largely replaced hot water injection because of its advantages demonstrated in both laboratory studies and field trials.
Continuous sterilization – It is a sterilization process which operates at high temperatures (typically 130 deg C to 150 deg C) for short holding times (8 seconds to 40 seconds) to effectively destroy micro-organisms while minimizing damage to heat-sensitive components. This method allows for rapid heating and cooling, making it more efficient than batch sterilization processes.
Continuous stirred tank reactor – It is an open reaction vessel where reactants are continuously fed in while products are simultaneously withdrawn under steady-state, well-mixed conditions. It is a well-mixed reactor where the conditions throughout the reactor are uniform and can be used to analyze reaction kinetics, including equilibrium and rate-based reactions. It needs a detailed understanding of kinetics for accurate prediction of by-products.
Continuous system – It is a dynamic setup where state variables change smoothly and continuously over time, taking any value within a given range rather than shifting in distinct steps.
Continuous testing – It is the process of incorporating automated feed-back at different stages of the software development life cycle (SDLC) in support of better speed and efficiency when managing deployments. Continuous testing is a critical driver behind the effectiveness of continuous integration or continuous delivery processes and plays a crucial role in accelerating software development life cycle time-lines by improving code quality, avoiding costly bottlenecks and expediting processes.
Continuous time – It refers to a formulation that models real-life scheduling problems without discretizing time into distinct intervals, allowing for better production schedules in the context of refinery operations.
Continuous-time case – It refers to a scenario, system, or signal where variables, inputs, and outputs are defined and evaluated continuously across every instant along a real-valued time axis t, rather than at fixed, discrete steps.
Continuous-time concept – It refers to a system, signal, or process defined and evaluated across a continuous, unbroken range of time values (t) rather than at separate, isolated steps.
Continuous-time Fourier transform – It is a mathematical operation in electrical and signal engineering which converts a continuous signal from the time domain ‘x(t)’ into a continuous representation in the frequency domain X(omega).
Continuous-time signal – It is a physical or mathematical quantity ‘x(t)’ defined for every single instant of time ‘t’ along a continuous real-valued interval.
Continuous-time system – It has continuous-time signals as its input and continuous-time signals as its output. Continuous-time systems are characterized by differential equations. Examples include analog filters and amplifiers.
Continuous turbulence – It refers to a random, statistically stationary process of fluid or atmospheric gusts which can be analyzed over short durations using Gaussian properties, while its intensity fluctuates randomly according to probability functions over longer durations.
Continuous-type furnace – It is a furnace used for heat treating materials which progress continuously through the furnace, entering one door and being discharged from another.
Continuous use temperature – It is the maximum temperature at which material can be subjected to continuous use without fear of premature thermal degradation.
Continuous variable – It is a numerical variable which can assume an infinite, uncountable number of real values within a given range or interval (such as height, temperature, time, or pressure). A numeric variable is continuous if the observations can take any value within an interval. Variables such as height, weight, and temperature are continuous. In descriptive statistics the distinction between discrete and continuous variables is not very important. The same summary measures, like mean, median, and standard deviation can be used. There is frequently a bigger difference once inferential methods are used in the analysis. The model which is assumed to generate a discrete variable is different to models which are appropriate for a continuous variable. Hence different parameters are estimated and used. In feature engineering and data science, continuous variable is the process of defining, transforming, and constructing continuous numerical features from raw data to improve machine learning model performance.
Continuous variation – It refers to a range of measurable differences or values for a parameter which can take any value along a smooth, unbroken continuum rather than falling into distinct, separate categories.
Continuous vector field – It is a vector-valued function which assigns a vector (with both magnitude and direction) to every point in a region of space, such that all of its individual component functions are continuous.
Continuous wave – It is an uninterrupted electro-magnetic or acoustic wave with a constant amplitude and frequency over time.
Continuous wave (CW) radar – It is a radar system which continuously transmits a radio frequency (RF) signal with a 100 % duty cycle while simultaneously receiving backscattered energy from a target. Instead of using pulses, it relies on the Doppler effect to measure a target’s radial velocity.
Continuous weighing – It is the dynamic process of real-time material flow measurement on a conveyor belt, needing periodic calibrations and vigilant checks to maintain a high level of precision.
Continuous weight function – It is a non-negative, real-valued function w(x) defined over a continuous domain which assigns relative importance, probability, or spatial influence to different points or states.
Continuous weld – It is a weld extending continuously from one end of a joint to the other or, where the joint is essentially circular, completely around the joint.
Continuous-welded cold-finished mechanical tubular product – It is the tube which has been hot formed by furnace butt welding and cold finished. It is furnished sink drawn or mandrel drawn and is available in outer diameter ranging from up to 90 millimeters and wall thicknesses from 0.9 millimeters to 13 millimeters. The material is low carbon steel, and the product is, in effect, a form of cold-drawn pipe. Although supplied in a narrower size range than electric resistance welded tubes, it has two advantages which are (i) within the available size range, heavier walls are available, and (ii) there is no problem with flash.
Continuous welded rail – It is also called long welded rail (LWR). It refers to a railway track where individual rail sections are welded together to form a continuous, unbroken length, frequently spanning several kilometers. This welding eliminates traditional joints and creates a smooth, seamless track.
Continuous welding process – In continuous (or furnace butt) welding process, skelp with square or slightly beveled edges is furnace heated to the welding temperature. The heated stock is roll formed into cylindrical shape as it emerges from the furnace. Additional heat is normally provided by an oxygen or air jet impinging on the seam edges, and the pipe passes through constricting rolls where the seam edges are welded by the pressure of the rolls.
Continuous Wigner function – It is also called Wigner quasi-probability distribution. It is a mathematical tool used in quantum mechanics, signal processing, and engineering to analyze a system in both position and momentum (or time and frequency) simultaneously. In electrical engineering, acoustics, and optics, it is heavily utilized for joint time-frequency analysis of non-stationary signals. For a continuous-time signal x(t), the Wigner distribution function (WDF) is defined as the Fourier transform of the signal’s time-dependent autocorrelation function.
Continuum – It is the non-characteristic rays emitted upon irradiation of a specimen and caused by deceleration of the incident electrons by interaction with the electrons and nuclei of the sample. It is also termed bremsstrahlung and white radiation.
Continuum approach – It is a modelling method which treats matter (solids, liquids, or gases) as a continuous, unbroken medium rather than as discrete individual molecules or atoms. It treats matter as a continuous, unbroken medium, ignoring discrete molecules and empty spaces.
Continuum assumption – It is a fundamental engineering and physics concept that treats matter (solids, liquids, and gases) as a continuous, smooth, and uninterrupted distribution of mass, rather than as discrete, individual molecules separated by empty space.
Continuum damage mechanics – It is a framework which models how microscopic flaws like tiny holes and microcracks progressively degrade a metal’s strength and stiffness at the macroscopic scale.
Continuum framework – It is a modelling method which treats matter as an unbroken, continuous medium rather than a collection of discrete atoms or molecules.
Continuum hypothesis – It is the working model which treats matter (such as liquids, gases, and solids) as a continuous, unbroken distribution of mass with no empty space, rather than as discrete, individual molecules.
Continuum mechanics – It is the science of mathematically describing the behaviour of continuous media. The same basic approach can apply to descriptions of stress, heat, mass, and momentum transfer.
Continuum mechanics approach – It is a method which models materials (solids and fluids) as a continuous, unbroken mass rather than as discrete particles, atoms, or molecules. By ignoring the micro-level atomic structure on length scales much larger than inter-atomic distances, engineers can use macroscopic field equations and calculus to analyze how materials deform, flow, and transmit forces under different loads.
Continuum mechanics model – It is a mathematical representation which treats materials as continuous media, neglecting the discrete atomic structure, to predict mechanical properties and behaviours, such as those of carbon nano-tubes (CNTs), using methods like finite element analysis.
Continuum mechanics theory – It is a framework in mechanics which describes the behaviour of materials by treating them as continuous, rather than discrete, entities, and can involve both stress-based and energy-based approaches to analyze failure and deformation.
Continuum model – It is a macroscopic simulation model which describes crowds as a fluid using average quantities such as density, where individual pedestrians are not represented. These models consist of partial differential equations which express the relationships between average speed, flow, and density at specific locations and times.
Contour – It is that portion of the outline of a transverse cross section of an extruded shape which is represented by a curved line or curved lines.
Contour definition drawing – It contains the mathematical, numeric, or graphic definition needed to locate and define a contoured surface. It does not establish item identification for the items described thereon. It is prepared to define complex surface geometry which cannot be conveniently included in the detail drawings of an item. It includes (i) mathematical equations for the geometric features, (ii) tabulated coordinates, (iii) graphic sections, and (iv) a summary of features and relationships to more basic coordinate systems in appropriate combinations to define the contoured surface or the desired points on a contoured surface.
Contour die – It is a specialized cutting or forming tool engineered with a specific non-linear, curved, or profile edge to match and cut or shape the outer boundary (contour) of a metal work-piece.
Contoured face – It refers to a complex, curved, or non-planar surface on a workpiece that is shaped using multi-axis computer numerical control (CNC) contour milling.
Contoured swing die – It is a specialized mechanical press tool designed to cut, trim, or form materials with non-flat, complex 3D surface profiles using a pivoting or rotational (swinging) motion.
Contour forging – It is a specialized metal shaping process where dies or rollers follow the specific outline of a part to produce complex near-net shapes with aligned grain flow.
Contour forming – It is also known as roll forming, stretch forming, tangent bending, and wiper forming.
Contour hardening – It is also called profile hardening. It is a heat treatment process which hardens only the outer surface layer of a geared or shaped component while maintaining a tough, ductile core. The process precisely follows the geometric contours of the part, such as the teeth and roots of a gear, ensuring uniform case depth and minimal dimensional distortion.
Contouring – It is the process of tracing and plotting imaginary lines on a map which connect points of equal elevation above a reference level, such as mean sea level.
Contour interval – It is the vertical distance or difference in elevation between two consecutive contour lines on a topographic map.
Contour lines – These are the point set of intersections between a topographic surface and a horizontal plane, described mathematically as a plane curve where elevation remains constant.
Contour machining – It is the machining of irregular surfaces, such as those generated in tracer turning, tracer boring, and tracer milling.
Contour map – It is a two-dimensional graphical representation of a three-dimensional terrain or surface, created by connecting points of equal elevation above or below a reference datum (such as mean sea level) using continuous lines called contour lines.
Contour mapping – It is an important technique in geographic representation which transforms the earth’s three-dimensional surfaces into a readable two-dimensional form. Through this process, maps depict elevations and landforms with contour lines which trace the same elevation levels, rendering an accurate representation of terrain features like hills, valleys, and slopes. The closeness of the contour lines indicates the steepness of the terrain: closely spaced lines suggest steep slopes, while wider spaced lines indicate gentle slopes. The contour interval, or the vertical space between successive lines, is constant on a given map, governing the map’s detail and readability based on the area’s topographical variation.
Contour method – It refers to the process of tracing contour lines (imaginary lines connecting points of equal elevation) to map 3D terrain onto a 2D drawing. It is also a technique for measuring full-field residual stress distributions within a prismatic sample by cutting through its cross-section and analyzing the surface height profiles of the cut surfaces to determine the stresses normal to the cut. This method provides a two-dimensional map of residual stress, distinguishing it from other techniques which yield one-dimensional profiles.
Contour milling – It is the milling of irregular surfaces. It is a CNC (computer numerical control) machining process where a rotating cutting tool follows a curved, irregular, or multi-axis path to shape the outer profile or internal boundary of a work-piece.
Contour plot – It is a two-dimensional graphical technique which represents a three-dimensional surface by plotting constant response or property values (called contour lines or isolines) across a plane defined by two input variables.
Contour ring rolling – It is an advanced metal-forming process which shapes a preformed metal ring into an irregular, profiled cross-section by adjusting the geometries of the rolling tools while increasing the ring’s diameter.
Contour roll forming – It is also known as roll forming or cold roll forming. It is a continuous process for forming metal from sheet, strip, or coiled stock into desired shapes of uniform cross section by feeding the stock through a series of roll stations equipped with contoured rolls (sometimes called roller dies). There are two or more rolls per station. Majority of the contour roll forming is done by working the stock progressively in two or more stations until the finished shape is produced.
Contour roll-forming machine – It is normally referred to simply as a roll former. It is a continuous, automated fabrication system designed to shape long strips of sheet metal, typically sourced from coiled steel, into a specific, uniform cross-sectional profile. The defining characteristic of this machine is progressive plastic deformation. The metal stock is continuously fed through a tandem series of consecutive roller stations. Each individual station is equipped with paired, precision-machined contoured roller dies which apply an incremental bending force to the moving material. By breaking down a complex shape into sequential, minor bends, the machine permanently deforms the metal into its final geometry without changing the nominal material thickness or introducing excessive residual structural stress.
Contour rolling – It is a continuous manufacturing process which shapes metal sheets, strips, or coiled stock into uniform, complex cross-sectional profiles by feeding the material through a progressive series of paired, contoured roller dies.
Contour strip mining – It is a mining method which is used to extract near-surface rock and mineral deposits (normally coal or iron ore) in hilly or mountainous terrain. Earth-moving equipment removes overburden and deposit from a series of benches cut along contours of elevation.
Contour surface milling – It is a precision CNC (computer numerical control) machining process where a rotating cutting tool follows a continuous, pre-programmed path along a complex curve, inclined plane, or three-dimensional freeform surface. Unlike flat-face or basic profile milling, it focuses on surface finishing, smooth transitions, and tight dimensional control rather than heavy, bulk material removal.
Contour welding – It very frequently refers to laser transmission contour welding or the surface profile geometry of a completed weld joint. It is a precision joining process for plastics. It is a process where a focused laser beam moves once along a predefined 2D or 3D path (the contour) to join two thermoplastic parts.
Contract – It is defined in short as an agreement between two or more parties enforceable under the law. A contract is a legally binding agreement between the parties identified in the agreement to fulfill all the terms and conditions outlined in the agreement. A prerequisite requirement for the enforcement of a contract, amongst other things, is the condition that all the parties to the contract accept the terms and conditions described in the contract. Historically, this was most commonly achieved through signature, but in many jurisdictions – especially with the advance of electronic commerce – the forms of acceptance have expanded to include various forms of electronic signature. Party/parties awarding the contract are known as the purchaser or employer. Party / parties agreeing to execute or perform the contract are known as the supplier or contractor. Contracts are of several types. They are normally classified as supply contracts, service contracts, management contract, transport contract, sales contracts, purchase contracts, design and engineering contract, training contract, maintenance contract, civil contract, and erection contract etc.
Contract clause – It is a specific, numbered, or lettered provision within an agreement which defines the exact rights, duties, performance expectations, financial terms, and risk-allocation rules between the parties (such as the owner, and contractor. Contract clauses are the specific provisions within a contract which outline the responsibilities and expectations of the parties involved, including incentives for timely completion and penalties for delays in project execution.
Contract drawings – The engineer can carry on with detailed design only after the completion of tender drawings. If tendering has been straight forward and without any alternative proposals, the contract drawings are the same as tender drawings. If alternate proposals have been accepted, new or additional drawings are to be prepared as per the accepted tender proposals and alternatives.
Contracted notation – It is frequently known as Voigt notation. It is a shorthand method which simplifies the representation of second-order stress and strain tensors. Instead of writing out a full 3 × 3 matrix (which has 9 components) or keeping redundant off-diagonal shear terms, contracted notation reduces the tensor into a 6-component column vector.
Contraction – It refers to the reduction in size, volume, length, or cross-sectional area of a material, fluid stream, or mathematical tensor because of the physical, thermal, or mechanical forces. It is the volume change which occurs in metals and alloys upon solidification and cooling to room temperature. In galvanizing, it is the shrinkage of steel due to cooling after removal from the galvanizing pot.
Contraction coefficient (Cc) – It is a dimensionless parameter defined as the ratio of the minimum cross-sectional area of a fluid jet. known as the vena contracta, to the total cross-sectional area of the opening or orifice through which the fluid flows. ‘Cc = Av/Ao’, where ‘Av’ is the area of the fluid jet at the vena contracta (point of maximum constriction), and ‘Ao’ is the cross-sectional area of the orifice, nozzle, or sluice gate.
Contraction cracks – These are fractures which occur when a material like concrete, asphalt, or metal reduces in volume because of the cooling or drying, and external or internal restraints prevent free movement. Since these materials are weak in tension, the restricted shrinkage builds up tensile stress until the material splits.
Contraction mapping – It is a function on a metric space that shrinks the distance between any two points by a fixed scaling factor strictly less than one. It forces points closer together with each application, guaranteeing a unique fixed point under the Banach fixed point theorem.
Contraction mapping principle – It also known as Banach fixed point theorem. It states that a contraction mapping on a complete metric space has a unique fixed point. Starting from any point, repeating the map creates a sequence which converges to this fixed point.
Contraction operation – It is frequently called a contraction mapping or contraction. It is a function or transformation applied to a space where the distance between any two points strictly decreases after the operation is performed. It is a core concept used in iterative engineering analysis, control systems, and computational fluid dynamics (CFD) to guarantee that a system settles into a stable, steady-state solution.
Contraction principle – It is also called the Banach fixed point principle. It is a fundamental mathematical theorem stating that a contraction mapping on a complete metric space always has one unique fixed point. It also provides an iterative method to find that point.
Contraction rule – It defines a function that brings points closer together by a constant factor less than one. This guarantees a single, stable solution (fixed point) for iterative calculations used in computer algorithms, system modeling, and structural analysis.
Contract life cycle management – It is defined as the process of systematically and efficiently managing contract creation, execution and analysis for maximizing operational and financial performance and minimizing risk. A contract life cycle has two distinct phases namely pre signing phase and post signing phase.
Contract management – It is the process which enables both parties to a contract to meet their obligations in order to deliver the objectives required from the contract. It also involves building a good working relationship between the contracting parties. It continues throughout the life of contract and involves managing proactively to anticipate future needs as well as reacting to situations that arise.
Contractor – Contractor is an individual or an organization hired under a legal agreement to execute, build, or manage infrastructure and technical projects as per approved designs, budgets, and timelines. Contractor performs a specific job, supply materials, or provide services under a binding agreement. Contractor is a party which enters into a legal contract.
Contractor control -It normally refers to the authority and responsibility a contractor has over the means, methods, techniques, sequences, and procedures used to execute the physical work specified in a contract.
Contract performance management, contract administration – Effective governance of the contract performance ensures that the purchaser/employer gets what is agreed and to the level of quality required under the contract. The performance under the contract must be monitored to ensure that the purchaser / employer continues to get value for money.
Contractual requirement – It is the systematic process of translating technical and operational system needs into legally binding obligations, performance thresholds, and acceptance criteria within a formal contract.
Contraflexure – It is a point on a beam where the curvature changes sign, occurring at locations where the bending moment is zero.
Contrast effect – It refers to the enhancement, diminishment, or distortion of a perceived value, physical property (such as brightness, colour, or weight), or performance metric caused by the immediate or successive exposure to a contrasting reference stimulus.
Contrast enhancement (electron optics) – It is an improvement in electron image contrast by the use of an objective aperture diaphragm, shadow casting, or other means.
Contrast filter – It is a colour filter, normally with strong absorption, which uses the special absorption bands of the objective to control the contrast of the image by exaggerating or diminishing the brightness difference between differently coloured areas.
Contrast function – It is a criterion used to define the extraction or separation of source signals. It is designed to find the global maxima which hat correspond to the desired solution, either extraction or separation. The definition of contrast functions involves principles that control the criteria and ensure optimality.
Contrast masking – It refers to the reduction in visibility of one image component (the target) caused by the presence of another image component (the masker) sharing a similar spatial location, frequency, and orientation.
Contrast perception – It is the ability to differentiate different components of the object structure by different intensity levels in the image.
Contrast ratio – It is the measure of the difference in luminance (brightness) between the lightest colour (white) and the darkest colour (black) a system can produce, expressed as a ratio such as 1000:1. It shows how many times brighter the white is compared to the black (bright / dark). A higher ratio means deeper blacks, brighter whites, sharper image details, and better text readability.
Control – It is a system for measuring and checking or inspecting a phenomenon. It suggests when to inspect, how frequently to inspect and how much to inspect. Control ascertains quality characteristics of an item, compares the same with prescribed quality characteristics of the item, compares the same with prescribed quality standards, and separates defective item from non-defective ones. For control a manual or automatic device is used for the regulation of a machine to keep it at normal operation. In case of automatic device, the device is motivated by variations in temperature, pressure, water level, time, light, or other influences.
Control actuation – It is the process of converting a control signal into physical motion or force to operate a mechanism, adjust a system, or regulate a process.
Control algorithm – It is a mathematical formula, logical sequence, or set of software instructions which acts as the brain of an automatic control system. It continuously processes data from input sensors, compares the actual state against a desired setpoint (target), and calculates the precise output commands for actuators (like motors, valves, or heaters) to minimize error and maintain system stability.
Control / analysis condition data file format – It is a structured specification used in engineering software, such as computer-aided engineering (CAE), finite element analysis (FEA), computational fluid dynamics (CFD), or automated testing system). It dictates how setup parameters, boundary conditions, and execution rules are formatted so a simulation solver or data analysis engine can read them accurately.
Control and instrumentation – It comprises or contributes to some of all of the following namely automatic control of plant, alarms and indications, visualization of plant parameters, facilities to allow manual plant control, automatic protection systems, and engineered safety features.
Control architecture – It is the structured framework and conceptual blueprint which defines how devices, sensors, controllers, networks, and software are organized to manage, direct, and regulate the behaviour of a system.
Control ball valve – It is an automatic throttling valve controlling flow or pressure in a pipeline, comprising a package involving a ball valve, an actuator, a positioner, and controlling instruments.
Control block diagram – It is a graphical representation which simplifies the analysis and design of control systems by depicting the relationships between different components, including transfer functions and feedback loops, to derive the closed-loop transfer function.
Control boundary – It is the real or imaginary line which isolates a specific object, system, or process from its surroundings to analyze mass, energy, momentum, or information flows.
Control break – It is a programming and data-processing technique which triggers special actions (such as printing subtotals, headings, or grand totals) when the values of a sorted data field (the control field) change. It refers to points in a programme where the flow of control is interrupted to perform specific functions, frequently used to summarize data, such as sales, by categorizing it as per different criteria.
Control bus – It is a collection of physical wires or signal lines in a computer or processor architecture which carries command, timing, and status signals between the central processing unit (CPU), memory, and input / output (I/O) devices.
Control cabinet – It is a protective metal or plastic enclosure which houses, organizes, and protects central electrical, electronic, and automation components, such as programmable logic controllers (PLCs), circuit breakers, relays, and power supplies, used to control machinery, power distribution, and industrial processes.
Control centre – It refers to a centralized physical space or a modular electrical assembly used to monitor, coordinate, and manage critical systems, machinery, or industrial processes.
Control chamber – It is an enclosed, specialized volume designed to precisely establish, regulate, and monitor specific physical, thermal, chemical, or mechanical conditions.
Control channel – It is a dedicated physical or logical pathway which carries signaling, synchronization, and management information rather than user data (such as voice or file downloads). It is necessary in cognitive radio architectures for managing coordination and access in dynamic spectrum access networks.
Control chart – The control chart is a graph used to study how a process changes over time. Data are plotted in time order. A control chart always has a central line for the average, an upper line for the upper control limit, and a lower line for the lower control limit.
Control concrete – It is the standard concrete mix used as a reference in studies, which typically demonstrates specific properties such as flexural strength against which recycled concrete incorporating crushed recycled concrete aggregates (CRCA) is compared.
Control console – It is a fabricated, physical, and electronic work-station which allows an operator to monitor, command, and regulate machinery, industrial processes, or digital systems. It serves as the main human-machine interface (HMI) where an operator observes data and executes physical or digital inputs.
Control constraints – These constraints refer to limitations imposed on system variables to ensure compliance with specific conditions during the control process, as exemplified by the integration of active hard constraints in the primal-dual feedback-optimizing control framework. These constraints are dynamically managed to minimize violations and optimize performance.
Control, corrosion – It refers to the strategies used to slow down the corrosion process of metals, which can include methods which act on the metal, the environment, or by separating the metal from its environment. These strategies encompass selecting corrosion-resistant materials, altering electric potentials, managing environmental conditions, and applying protective coatings.
Control culture – It refers to how an organization or a team shapes the values, beliefs, and behaviours of its members to align with corporate goals. It is a system of normative control where management replaces direct, rigid supervision with a shared cultural framework. Workers internalize the organizational mission so that self-direction and peer pressure drive performance. In control systems engineering, combined with the operational culture of safety and precision, it is the technical and operational environment focused on designing, tuning, and maintaining systems which automatically regulate physical processes (such as temperature, speed, or pressure) to behave in a stable and repeatable manner.
Control cycle – It is a continuous, closed-loop feedback mechanism which monitors a system’s output, compares it to a desired target (set-point), and adjusts the input to minimize error. It defines the relationship between the demand source and the supply source.
Control data – It involves structuring, governing, and standardizing the information streams, parameters, and interlocks required to safely and accurately operate a physical or digital system. It is the immediate information a controller or programmable logic controller (PLC) needs to run a machine safely (such as proximity switches, interlock states, or sensor thresholds.
Control design – It is the iterative process of developing a mathematical or algorithmic controller which forces a physical system (the plant) to behave in a desired, stable, and predictable manner.
Control differential – It is the range or difference between the value at which a controller turns an output (like a heater, cooler, or valve) on and the value at which it turns it off. It prevents rapid, continuous cycling (known as hunting) of a mechanical relay or actuator.
Control drawings – Control drawing is that drawing which is used for the control of certain activities. There are usually six categories of control drawings namely (i) procurement control drawing, (ii) vendor item drawing, (iii) source control drawing, (iv) design control drawing, (v) interface control drawing, and (vi) identification cross reference drawing.
Control dynamics – It refers to the study of how systems change over time (process dynamics) and how to regulate, direct, or stabilize those behaviours (control systems) to achieve a desired performance.
Control effectiveness – It is a measure of how successfully a physical or systemic safeguard reduces the likelihood or severity of a hazard.
Control emissions – It refers to measures such as process change, raw material substitution, and equipment modification implemented to reduce or eliminate the release of pollutants into the atmosphere from a source.
Control engineer – Control engineer is a professional who designs, programs, tests, and maintains automated systems which regulate the behaviour of machinery and industrial processes. Control engineers apply control theory, mathematics, and engineering principles to make systems run safely, accurately, and efficiently with minimal human intervention.
Control engineering – It is an engineering discipline which applies control theory to design, analyze, and manage systems so they behave in a desired, stable manner without constant human intervention.
Control enhancement – It is an upgrade or addition to a base-line control which increases its overall strength, adds functionality, or improves system assurance.
Control equipment – It refers to the hardware and devices used to manage, direct, and regulate the behaviour of other systems or industrial processes.
Control experiment – It is an experiment in which all variable factors have been kept constant and which is used as a standard of comparison to the experimental component in a controlled experiment.
Control expression – It refers to a mathematical formulation added to the pseudoinverse Jacobian solution that biases joint angle rates toward specific desired values without affecting the end effector velocities. It is utilized to encourage joint angle constraints while allowing for a more controlled kinematic model.
Control factors – These are also known as control variables. These are factors which are kept constant or held constant during an experiment or study to ensure that the observed effects are because of the manipulated variable(s) and not to other, potentially confounding variables. They help to isolate the effect of the independent variable on the dependent variable.
Control flow – It is the sequence of operations executed in a program, represented graphically by a control-flow graph (CFG), which models the flow of control between basic blocks, with each node corresponding to a basic block and each edge indicating possible transfers of control.
Control flow graph – It is a directed graph representation which maps all possible paths of execution through a programme’s source or intermediate code.
Control flow state machine – It is a behavioral design pattern and engineering model used to manage complex execution paths by representing a system as a finite number of states, transitions, and actions. Unlike data-driven state machines, a control flow state machine (CFSM) focuses strictly on governing the order of operations and execution logic within software or hardware systems.
Control function – It is the specific mathematical or physical operation performed by a controller to regulate a system’s output and match it to a desired target value.
Control gate – It is a movable mechanical barrier or structure used to control the passage or flow of water through a channel, lock, canal, or dam. Control gates are mechanical or hydraulic barriers, such as sluice gates, spillway gates, or dam inlets, which regulate the flow rate of water through channels, penstocks, or reservoirs using gravity and mechanical actuators.
Control grid –It is a wire mesh or helix electrode placed between the cathode and the plate (anode) in a thermionic vacuum tube (such as a triode, tetrode, or pentode).
Control hierarchy – It refers to a multi-layer organizational tree structure where commands flow down from higher abstract layers and sensor data flows up from lower reactive layers.
Control instrumentation – It is the collection of devices, sensors, transmitters, controllers, and actuators used to measure, monitor, and automatically regulate physical and chemical variables in industrial processes.
Control interface – It is the boundary, specification, or physical-logical mechanism through which different sub-systems, components, or humans interact, exchange data / energy, and manage operations.
Control item – It is a specific hardware, software, equipment or a component which is formally designated for tracking and change control. A control item is an entity within a system design which has baseline functional and physical characteristics. It needs strict authorization and documentation before any modifications or upgrades can occur. It helps operational teams maintain product integrity and compatibility across different project versions.
Controllability – It is the ability of a system to be transitioned from an arbitrary initial state to a final state within a specified number of sampling intervals, contingent upon the rank of the controllability matrix being equal to the number of system states. Controllability is a basic property of systems which is indicative of the ability to control. Controllability and optimal control normally are recognized as the characteristics of modern control theory.
Controllability Grammians – These refer to the discrete-time controllability Grammian, which satisfies the discrete Lyapunov equation and is symmetric positive definite if and only if the system defined by the pair (A, B) is controllable.
Controllability index – It is an arbitrary initial state to any desired final state.
Controllability matrix – It is a special matrix in control systems engineering used to check if a dynamic system’s state variables can be completely influenced and steered to any arbitrary final state using its available control inputs.
Controllable input – It is a variable or signal [u(t)] which can be directly adjusted and manipulated from the outside to drive a system’s internal state variables from any initial state to any desired final state within a finite time. In broader engineering and product/system design, it refers to an actionable lever or metric that you directly influence to shape an outcome, rather than an uncontrollable environmental disturbance or a lagging end-result.
Controllable mode – It is a specific dynamic state or modal component of a system which can be directly influenced, excited, or driven to any desired state using the available control inputs.
Controllable pair – It is a pair of matrices (A, B) from a linear time-invariant (LTI) state-space model which satisfies the algebraic and geometric conditions for complete state controllability.
Controllable pitch propeller – It is a propulsion system where the propeller blades can rotate around their longitudinal axes inside the hub to change their pitch angle while the shaft and engine continue to rotate at a constant speed.
Controllable system – It is a dynamic system where an external control input can steer the internal state variables from any arbitrary initial state to any desired final state within a finite quantity of time.
Control law – It is a mathematical formula or algorithm used by a controller to calculate the input signal (u) sent to a system (called a plant). It determines how the system reacts based on desired targets (set-points), current system measurements (feed-back), and external predictions (feed-forward) to maintain stability, accuracy, and optimal performance.
Controlled access area – It is a specially designated and demarcated space where entry is strictly limited to authorized personnel to protect workers from specific hazards or to maintain physical and electronic security.
Controlled area – It is an area outside a restricted zone but within the site boundary of a facility. Access to such an area can be limited for any reason.
Controlled atmosphere – It is a specified inert gas or mixture of gases at a pre-determined temperature in which selected processes take place. As applied to sintering of powders, it is to prevent oxidation and destruction of the powder compacts.
Controlled auto-Ignition – It is an internal combustion engine process where a pre-mixed fuel-air-diluent charge spontaneously ignites from compression heat without needing a spark plug. Controlled auto-ignition (CAI) is a lean combustion mode which does not need the necessity of a lean exhaust gas aftertreatment on the gasoline engine. Controlled auto-Ignition engines normally use variable valve actuation (VVA) to achieve the controls on air charge mass, gas composition and charge temperature in addition to the benefit of pumping loss reduction due to the throttle-less operation. Controlled auto-Ignition considerably improves fuel economy and greatly reduces nitrogen oxides (NOx). .
Controlled blasting – It is the blasting patterns and sequences designed to achieve a particular objective. Cast blasting, where the muck pile is cast in a particular direction, and deck blasting, where holes are loaded once but blasted in successive blasts days apart, are examples.
Controlled bridge – It refers to an improved short-circuiting operation in welding which reduces heat input and spatter during the transfer of the filler wire to the weld puddle. This process stabilizes the weld arc by adjusting current and voltage based on the interaction between the filler wire and the weld puddle, addressing issues like turbulence and enabling welding with lower heat input.
Controlled chemical reaction – It is a chemical process managed and regulated by adjusting external factors like temperature, pressure, concentration, or adding catalysts to achieve a specific, safe, and desired outcome.
Controlled condensation – It is the regulated phase change of a gas or vapour into a liquid by actively managing external physical factors such as temperature, pressure, gas velocity, and surface characteristics.
Controlled contribution – It refers to the quantitative breakdown of different physical or chemical mechanisms (such as capacitive against diffusion-controlled processes) which that drive the total response or current of a system.
Controlled cooling – It consists of cooling a metal or alloy from a high temperature in a pre-determined manner to avoid hardening, cracking, or internal damage, or to produce desired micro-structure or mechanical properties.
Controlled cooling conveyor (CCC) system – It plays a key role in getting a consistent high quality throughout the wire rod coil. This system is important for the processing quality wire rod products, achieving desired uniformity, and metallurgical and mechanical properties. It tightly controls the around-the-ring tensile strength variations on fast-cooled products to a standard deviation within 1 % of the average tensile strength. By a proper selection of cooling regime, the system accommodates production of all conventional grades of steel as well as special product grades with alternative cooling modes. It also optimizes processing of carbon and alloy steel grades when used in conjunction with the reducing and sizing mill for low-temperature rolling and controlled cooling, producing a very good combination of properties and dimensional control. The system facilitates processing in a wide range of conditions, including both fast-cooling and slow-cooling modes within a single system. This capability enables wire rod mills to produce a broad spectrum of plain carbon and alloy steels, as well as stainless steels and other specialty grades.
Controlled current source – It is a circuit element which delivers an electrical current whose value is not fixed, but is instead determined by a voltage or a current located elsewhere in the circuit. Unlike independent current sources, which supply a constant output regardless of circuit conditions, controlled sources act as active or modelling components (such as in transistors and amplifiers). There are two main types of controlled current sources depending on what controls them. These are voltage controlled current source, and current controlled current source.
Controlled damper – It is a mechanical valve or device used to regulate, restrict, or modulate the flow of a fluid (such as air or gas) or absorb mechanical kinetic energy within a system.
Controlled devices – These are defined as devices which consist of an actuator responding to signals from a controller to operate final elements, such as valves or dampers, which can have non-linear responses to input. These devices include electric relays, solenoids, and pneumatic systems, frequently incorporating feed-back mechanisms to ensure accurate positioning for desired outputs.
Controlled dissolution – It is a process where the rate at which a solid substance dissolves into a liquid is intentionally regulated using physical barriers, chemical properties, or structural matrices.
Controlled-dwell extrusion – It refers to a manufacturing process variation where the material being extruded is intentionally held (or dwelled) under specific temperature and pressure conditions within a section of the extruder for a precisely controlled duration before passing through the die. Unlike standard continuous extrusion where the material flows dynamically from feeding to shaping, controlled-dwell engineering modifies the residence time to achieve uniform material transformation.
Controlled-dwell phase – It refers to a pre-programmed, precisely timed period within an operational cycle during which a system, tool, or component remains static, undergoes no dimensional movement, or maintains a constant state (such as pressure, temperature, or load) while surrounding inputs continue.
Controlled energy flow forging machines – These are advanced metalworking equipment which regulate the speed, force, and displacement of a ram to shape metal through precise plastic deformation while optimizing internal grain structure. These are mechanical, hydraulic, or servo-controlled presses which dictate exact energy delivery rates to manage material flow behaviour.
Controlled etching – It is the electrolytic etching with selection of suitable etchant and voltage resulting in a balance between current and dissolved metal ions.
Controlled experiment – It is a test where researchers change only one independent variable while keeping all other environmental, physical, and operational factors strictly constant to measure its exact impact on a dependent variable.
Controlled fatigue – It typically refers to either stress-controlled (high-cycle) or strain-controlled (low-cycle) fatigue testing and design methodologies used to predict how a material behaves under repetitive, fluctuating loads.
Controlled final alpha-beta deformation processing -It is a specialized thermo-mechanical technique used mainly in titanium and zirconium metallurgy. It involves precisely applying mechanical strain (such as forging or rolling) within the dual-phase alpha plus beta temperature window, typically 30 deg C to 50 deg C below the beta transus temperature, as the definitive shaping step. The main objective of this process is to permanently break down brittle, coarse lamellar structures inherited from prior high-temperature liquid or solid processing and replace them with a fine, equiaxed, and microstructurally balanced morphology which yields high fatigue resistance and high fracture toughness.
Controlled flow conveyor – It is a purpose-built conveyor system engineered for methodical material flow regulation, prompting systematic inspections to ensure unwavering system integrity and meticulous material control.
Controlled forging – It is a manufacturing process where solid metal is shaped using precise compressive forces while closely regulating parameters like temperature, material flow, and deformation rates.
Controlled gate – It refers to a structural or logical component where the execution or action of a system is conditionally triggered or governed by an input, signal, or control state.
Controlled interface – It is a managed boundary with explicit mechanisms and rules which dictate and restrict how information, signals, or physical elements flow between inter-connected systems or sub-systems.
Controlled intermediate-grain-size processing – It is a manufacturing technique used to optimize the micro-structure of metals and alloys. It involves precise thermal and mechanical treatments to maintain a specific, uniform grain size which is neither too coarse nor too fine, balancing strength and ductility.
Controlled model – It refers to the systematic process of building, simplifying, and managing mathematical or physical representations of systems (plants) to design and test control algorithms.
Controlled or measured variable – It is the monitored output variable from a process. The value of the monitored output parameter is normally held within tight given limits.
Controlled-potential coulometry – Substances determined by controlled-potential coulometry are electrolyzed in a portion of the sample solution using the methodology of controlled-potential electrolysis. A specially designed electrolysis cell and feedback controller called a potentiostat is used. The conditions for analytical coulometry are designed to electrolyze only the desired substance (among possibly several in a mixture) and to convert the substance rapidly and completely to a desired product. For example, electrolysis of a metal ion species can result in its transformation to a soluble species of another oxidation state or reduction to a metal deposit on the electrode, as in electroplating.
Controlled-pressure cycle – it is a forming cycle during which the hydraulic pressure in the forming cavity is controlled by an adjustable cam which is coordinated with the punch travel.
Controlled radical polymerization – It is also called reversible-deactivation radical polymerization (RDRP) or living radical polymerization. It is a method of polymer synthesis which allows precise control over molecular weight, narrow molecular weight distribution, and complex polymer architecture.
Controlled radius – It is a specialized radius specification which needs a circular feature or fillet to form a smooth, continuous ‘fair’ curve without any flats, waviness, or reversals.
Controlled rectifier – It is an electrical circuit which converts an alternating current (AC) input into a variable or adjustable direct current (DC) output voltage. Unlike a standard diode rectifier (which provides a fixed direct current output), a controlled rectifier uses semi-conductor switches with a gate control, such as silicon-controlled rectifiers (SCRs) or thyristors.
Controlled release – It is the planned delivery of an active substance (such as a chemical) at a predictable rate, time, or location rather than all at once.
Controlled rolling – It is a hot-rolling process in which the temperature of the steel is closely controlled, particularly during the final rolling passes, to produce a fine-grain microstructure.
Controlled space – It very frequently refers to a physical area surrounding sensitive equipment, where access is restricted, monitored, and guarded against unauthorized entry.
Controlled-speed machine – It is a mechanical or electrical system equipped with a feed-back or regulating device, such as a governor, inverter, or computer controller, to maintain or adjust its operating speed under varying loads. Controlled-speed machines are designed to intentionally adjust and maintain a specific operational velocity despite changing external loads or process requirements.
Controlled stretching – It consists of stretching, under controlled tension, of plate and sheet products to a specified extension (percentage permanent set). It relieves internal stress and minimizes distortion during machining as well as improving flatness and straightness.
Controlled variable – It is the specific process parameter which a system measures and actively maintains at a desired set point or within a target range.
Controlled voltage source – It is an active circuit element which produces an output voltage determined by a voltage or current existing at another location in the circuit. Unlike an independent voltage source, which supplies a fixed or pre-determined voltage, a controlled voltage source changes dynamically as the controlling signal changes.
Controlled zone – It is a designated space where specific environmental conditions, access rules, or operational parameters are strictly managed to protect workers, maintain equipment safety, or ensure process integrity.
Controller – It is a device receiving a process variable (PV) signal from a primary sensing element (PSE) or transmitter, comparing that signal to the desired value (called the set point) for that process variable, and calculating an appropriate output signal value to be sent to a final control element (FCE) such as an electric motor or control valve.
Controller area network – It is a robust, message-based serial communication bus standard which allows micro-controllers, sensors, and electronic control units (ECUs) to communicate with each other in real time without a central host computer. It is standardized under International Organization for Standardization standard ISO 11898.
Controller design – It is the iterative process of developing a mathematical algorithm or hardware device, known as a controller, which forces a physical system (the plant) to behave in a desired, stable manner.
Controller gain – It is the numerical parameter in a control system which defines the proportional relationship and ratio between the error input (the difference between the desired set-point and the actual process variable) and the resulting controller output.
Controller parameters – These are specific values used in the tuning of a proportional–integral–derivative (PID) controller, which include the controller gain, integral time, and derivative time, and are contingent on the type of controller and the characteristics of the process being controlled.
Controller parametrization – It is the mathematical process of representing the entire family or set of all possible controllers (typically Youla–Kucera or YK parametrization) which can internally stabilize a given plant or system.
Controller response – It is the action or output generated by a local or centralized controller to minimize the error between a system’s desired target (setpoint) and its actual measured output (process variable).
Controller speed – It refers to how fast a control system or speed controller can process input signals, calculate errors, and adjust output power (such as voltage, frequency, or pulse-width modulation) to match a target speed or flow rate.
Controller structure – It specifies the architectural arrangement of components, signal paths, and control algorithms used to regulate a physical system (plant) to meet desired performance, stability, and safety goals.
Controller synthesis – It is the automated or systematic process of constructing a controller so that a given physical system or plant meets specific performance, stability, and safety requirements by construction.
Controller tuning – It is the process of adjusting the internal parameters of a feedback controller, very frequently a proportional-integral-derivative (PID) controller, so that the controlled system (or plant) reacts safely, accurately, and quickly to changes. Controller tuning is the process of finding the optimum tuning parameters for a controller to ensure stable and effective closed-loop system performance, minimizing issues such as oscillations and instability. Different methods, including those based on process reaction curves and internal model control (IMC), are used to determine key parameters for successful tuning.
Control limits – These are limits on control charts calculated on the basis of data collected under controlled conditions. Values outside these limits indicate the presence of an assignable cause and need for corrective action.
Controlling – It is the process whereby organization sets itself performance objectives and strives to achieve them as best it can over time.
Controlling authority – It refers to an official regulatory body, designated person, or statutory organization which holds the legal or organizational power to set standards, approve designs, and mandate compliance.
Controlling material – It refers to the regulation of the flow rate of materials in a conveying system, which can be achieved by adjusting the position of the outer sleeve relative to the pipeline and by managing the airflow through primary and secondary air supplies. This process ensures efficient material entrainment and prevents blockages in the system.
Controlling membrane – It is a selective barrier which regulates the release rate of an active agent or controls the transport of specific components between two adjacent fluid, based on the agent’s solubility, diffusivity, pore size, and the driving force (such as pressure, concentration, or electrical gradients). It forms the core of membrane separation technologies (like reverse osmosis, ultrafiltration, and gas separation) to fractionate mixtures, purify water, or isolate specific molecules.
Controlling parameter – It is a specific variable or boundary condition that dictates, guides, or heavily influences the behaviour, output, or state of a system.
Controlling structures – It refers to the deliberate manipulation of a metal’s internal microscopic arrangement, such as grain size, phase distribution, and crystal lattice defects, to achieve specific mechanical properties like strength, hardness, and ductility.
Controlling voltage – It refers to the systematic management of voltage levels within a power system, which is achieved through a hierarchical approach involving automatic voltage regulators for primary control, coordinated reactive power injection for secondary control, and manual adjustments for tertiary control. This process ensures that voltage remains at desired set points by allowing the supply and absorption of reactive power.
Control logic – It is the set of rules, programmes, or operational steps which a controller uses to make decisions and manage how a reactive system or machine responds to events. It is the sequence of operations and decisions implemented in programmable logic controllers (PLCs) to manage and automate different systems, ensuring that the needs specified in informal documentation are accurately translated into functional control programmes.
Control loop – It is a continuous feed-back mechanism which automatically monitors a physical property, compares it to a target value, and adjusts system operations to minimize any difference.
Control loop band-width – It is the frequency range over which a closed-loop control system can effectively track a reference command or reject a disturbance before its amplitude response drops by -3 dB (around 70.7 % of its low-frequency direct current gain).
Control loop speed – It refers to how fast a closed-loop control system samples a process variable, calculates an error signal, and updates its control output (such as voltage, torque, or valve position). It is often measured in terms of sampling frequency (hertz), cycle time (milli-seconds), or loop band-width (radians per sec).
Control mass – It is a thermodynamic framework which represents a fixed, unchanging quantity of matter enclosed within a defined boundary, normally known as a closed system.
Control matrix – It is a structured tool or framework used to map out system goals, operational risks, and the specific control mechanisms designed to prevent, detect, or correct errors. It is a mathematical matrix used in control theory to determine whether a linear time-invariant (LTI) system is controllable.
Control model – It is a simplified representation of a system used in model-based control methods, distinct from simulation or emulator models. It serves to facilitate control algorithm testing and design, frequently derived through techniques such as system identification or model order reduction.
Control module – It is a self-contained hardware-software system which supervises, regulates, and manages electronic, mechanical, or industrial processes by processing sensor inputs and driving actuators. It is a collection of basic control logic, sensors, actuators, and processing units operated as a single entity to execute basic control and minimal coordination.
Control moment gyros – These are key actuators used for fast maneuvering and high-precision attitude control of large spacecraft. They rely on rotor bearings, which are important for system stability and longevity, and are susceptible to degradation from factors such as abrasion and fatigue.
Control network – It is a specialized communication infrastructure which connects sensors, actuators, and controllers to manage, monitor, and automate physical processes in real time.
Control of material flow – It is the systematic regulation, coordination, and optimization of physical goods and related information as they move through a facility or supply chain. It ensures that the right materials arrive at the exact place, at the right time, in the required quantity and quality.
Control of contaminant – It is the systematic practice of identifying, measuring, limiting, and removing unwanted biological, chemical, or physical substances from systems, environments, or products.
Control of contamination – It is the systematic series of practices, procedures, and technologies designed to prevent the introduction, proliferation, and spread of unwanted impurities (microbial, chemical, physical, or particulate) in a controlled or manufacturing environment.
Control of a mechanical system – It refers to the application of control theory to influence, direct, and regulate the motion, forces, and energy of a mechanical device or machine so it performs a desired task with accuracy, stability, and efficiency.
Control oil pressure – It refers to the fluid pressure within a hydraulic control circuit used to operate, position, or regulate heavy machinery, turbines, or governors. It is the specific hydraulic pressure maintained in a control or servo system to actuate valves, guide mechanisms, or safety trips.
Control operation – It is a series of hardware or software actions within a system which governs, regulates, or processes data, execution, or mechanical behaviour to produce a specific, predictable result. Since a control operation is executed with both the system hardware and software, stable and repeatable operations represent the capability of the hardware, the software, and their mutual compatibility in this respect. Stable operation needs that the system is required to produce exactly the same result for any given set of input data or events within the same time frame.
Control panel – It is a flat, frequently vertical, area where control or monitoring instruments are displayed or it is an enclosed unit that is the part of a system which users can access, such as the control panel of a reheating furnace. It is also called control unit.
Control parameter – It is an adjustable setting or boundary condition used to regulate, tune, or constrain the behaviour of a system. Controller parameters are specific values used in the tuning of a PID (proportional integral derivative) controller, which include the controller gain, integral time, and derivative time, and are contingent on the type of controller and the characteristics of the process being controlled.
Control plane – It is the part of a network, cloud system, or container platform which makes decisions about how data is to be handled, routed, or processed, rather than actually moving the data itself.
Control polygon – It is an ordered sequence of control points connected by line segments which defines, approximates, or manipulates the shape of a parametric curve or spline, such as a Bezier curve or NURBS (non-uniform rational B-spline).
Control production system – It is an integrated framework of software, hardware, and operational processes used to direct, monitor, and adjust the flow of materials and work through a manufacturing system. Its main purpose is to execute strategic production plans efficiently, ensuring that orders are completed on schedule, within quality standards, and at minimal cost.
Control qubit – It is a quantum bit in a multi-qubit gate operation which dictates whether a specific transformation or logic state change occurs on another qubit, known as the target qubit, based on its own quantum state. In quantum engineering, qubit control refers to the physical and electronic methods used to steer, initialize, manipulate, and read out a qubit’s state with high fidelity while preventing decoherence and cross-talk.
Control regime – It refers to the specific set of rules, algorithms, operating parameters, and feedback structures which are used to regulate the behaviour of a physical process, machine, or system over time.
Control register – It is a specialized processor or hardware register that stores configuration bits and control flags to change, enable, or manage the behavior of a CPU (central processing unit), micro-controller, or peripheral device.
Control relationship – It refers to the mathematical, algorithmic, or architectural dependency between different variables, components, or systems where one entity directly regulates, influences, or commands the behaviour of another.
Control research – It is the scientific study of how to design algorithms, models, and physical hardware to regulate the behaviour of dynamic systems, such as machines, or power grids, so they achieve a desired performance, stability, and safety.
Control rods – These are the devices to absorb neutrons so that the chain reaction in a reactor core can be slowed or stopped by inserting them further, or accelerated by withdrawing them.
Control rolled steels – These steels are hot rolled as per predetermined rolling schedule designed to develop a highly deformed austenite structure which then transforms into a very fine equiaxed ferrite structure on cooling.
Control room – It is a room from where the operator operates the process or the equipment. The control room houses several displays for displaying the process parameters, control panels, as well as control and monitoring equipments and instruments.
Control run – It is a model run carried out to provide a ‘baseline’ for comparison with climate change experiments. The control run uses constant values for the radiative forcing because of the green-house gases and anthropogenic aerosols appropriate to pre-industrial conditions.
Controls – These refer to the devices, circuits, and systems used to manage, direct, and regulate the behaviour of electrical equipment or power. An electrical control system works on a simple input-process-output cycle to maintain safety, accuracy, and efficiency. In logistic regression, controls are the units of analysis which have not experienced the event of interest.
Controls, alarms, and interlocks – These form a three-tier hierarchy of safety and operational management systems designed to regulate processes, warn human operators, and automatically prevent equipment damage or hazards. Controls actively manage and adjust ongoing process variables (like temperature, pressure, or flow) to keep the system running at desired normal set-points. Alarms notify human operators through visual or audible signals that a process condition requires assessment or intervention, without taking automatic physical action. Interlocks are logical or physical safety constraints which automatically permit, prevent, or alter machine operations based on predefined conditions (such as a permissive start or an automatic trip / shutdown).
Control scheme – It is a systematic arrangement of control algorithms and logic blocks that manage the operation of a system, utilizing inputs such as load current and pre-defined values to detect faults and generate outputs which regulate system components like semi-conductor switches and mechanical contacts.
Control sensor – It is a device which measures a physical, or chemical variable (such as temperature, pressure, flow, or position) and converts it into a measurable electrical or digital signal. In a closed-loop control system, this signal provides real-time feedback to a controller, micro-processor, or programmable logic controller (PLC) so the system can automatically adjust and regulate operations to match a desired set-point.
Control server – It is a supervisory controller within a distributed control system (DCS) which communicates with distributed field controllers, sending set-points and requesting data to manage localized production processes effectively.
Control signal – It is an electrical, pneumatic, or digital command computed by a controller and sent to an actuator or plant to regulate, direct, or command the behaviour of a system. Unlike data signals which carry raw information (like text or sensor readings), control signals manage timing, coordination, and operational adjustments. In a closed-loop system, the control signal is typically calculated based on the error, the difference between the desired set-point and the actual measured output.
Control strategy – It is a planned set of controls, rules, or procedures derived from system understanding which ensures consistent performance, safety, and quality. It also refers to a set of designed structures aimed at regulating a system with limited actuator availability, ensuring the fulfillment of control objectives in an intensified process.
Control structures – These refer to the means by which the execution flow of a programme is guided in order to process data. These structures include branches, concurrency, selection, iteration, and triggers, which are implemented in different programming languages to enable conditional and repetitive execution of tasks. Control structure refers to any element in a computer programme which alters the normal sequential flow of execution, allowing for branching or repetition of code based on certain conditions or variables.
Control surface – It is a physical device or an imaginary boundary which alters the motion, direction, or state of a system. Control surfaces refer to the specified boundaries which a surface is required to reside within to be accepted, typically defined by a tolerance zone in three dimensions. They are normally used to control the size, orientation, and form of different geometric shapes in engineering applications.
Control synthesis – It is the process of designing and constructing a controller which forces a given dynamic system, known as a plant, to meet a specific set of stability, safety, and performance requirements.
Control system – A control system manages, commands, directs, or regulates the behaviour of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial control systems which are used for controlling processes or machines. The control systems are designed through control engineering process.
Control system analysis – It is the process of using mathematical and graphical methods to evaluate the dynamic behaviour, performance, and stability of a feedback-controlled system without changing its core parameters.
Control system design – It is the process of building and tuning a system, using mathematical modelling, sensors, actuators, and controllers, to manage, direct, or regulate the behaviour of devices or processes so they achieve a desired output with stability and efficiency.
Control system management – It refers to the design, implementation, and oversight of the different control mechanisms (such as managing, commanding, directing, or regulating) to ensure systems operate safely, accurately, and efficiently under varying conditions.
Control system structure – It is an important step in process control design. The selection of control system structure is based on the type of control used for the process/plant. A centralized multi-input multi-output (MIMO) controller or a set of single-input single-output (SISO) controllers can be used to control a distributed or decentralized process. A decentralized type of control system is more common than the centralized control system in the process industry, as it has more captivating advantages such as it is easy to understand, it uses uncomplicated hardware, and it employs simple working algorithms. On the other hand, centralized type of control e.g., Model Predictive controllers (MPC), has several limitations such as higher maintenance cost, difficulties in operation, complicated structure, and lack of flexibility which can result in fragile controller. However, centralized controllers have the potential to operate systems at optimal levels, which can potentially have noticeable economic benefits.
Control system synthesis – It is the process of constructing a controller which causes a given plant to meet a specified set of performance and stability requirements. Where analysis examines the properties of an existing system, synthesis starts from a set of closed-loop objectives, such as rise time, overshoot, gain margin, or disturbance rejection, and works backward to determine what controller structure and parameter values are going to achieve them. The problem spans classical frequency-domain techniques, state-space methods, and modern optimization-based formulations, and it applies to systems ranging from simple single-loop regulators to multi-input, multi-output industrial processes.
Control tower – It is also called a unified operations control (UOC) centre. It it is a single visual platform which consolidates plant-floor production, quality, maintenance, energy, and safety data. It is also a centralized, digital, and organizational hub which integrates real-time data, operational metrics, and event flows across an end-to-end supply chain.
Control transformer – It is a specialized dry-type, step-down electrical transformer designed to supply a safe, stable, and regulated low voltage to control and auxiliary circuits in industrial machinery and panels.
Control transmission – It refers to the electronic and hydraulic management of a vehicle’s transmission to optimize gear ratios, fuel economy, and shifting quality. It also refers to transmission control protocol, which is a connection-oriented, reliable transport-layer protocol that facilitates the organized exchange of data packets between devices across a network.
Control unit – It is a component of a computer’s central processing unit which directs the operation of the processor. It typically uses a binary decoder to convert coded instructions into timing and control signals that direct the operation of the other units (memory, arithmetic logic unit and input and output devices, etc.).
Control valve – It is a valve which controls a process variable, such as pressure, flow or temperature, by modulating its opening in response to a signal from a controller.
Control valve manifold – It is an integrated assembly of multiple valves, ports, and internal fluid passages housed within a single metal or plastic block. It routes, regulates, and monitors fluid or gas flow while allowing operators to isolate, equalize, vent, or drain a system without a complete shutdown.
Control variable – It is a factor which is kept constant (unchanged) foe ensuring that the observed changes in the dependent variable are solely because of the independent variable being tested. Control variables are not the main focus of the investigation but are necessary for maintaining experimental validity and avoiding confounding effects. Control variables are crucial for isolating the effect of the independent variable on the dependent variable. By keeping other factors constant, persons investigating can be more confident that any changes observed in the dependent variable are a result of the manipulated independent variable, rather than other variables.
Control volume finite element method – It is a hybrid numerical technique which combines the geometric flexibility of the finite element method (FEM) with the strict conservation principles of the finite volume method (FVM).
Control wiring – It is the low-voltage and low-current electrical circuitry used to transmit operational commands, feedback signals, and data between components, such as switches, relays, sensors, and programmable logic controllers (PLCs), rather than delivering high-power energy to heavy equipment.
Control zone – It is a restricted work area on a construction site (marked by warning lines, signs, or physical barriers) where entry is permitted only for authorized, trained personnel. It is also a high-voltage electricity network area managed by a single transmission system operator (TSO). Control zone is also a localized indoor space where thermal factors, humidity, and air purity are mechanically regulated. It is also a temporary segment set up along a roadway during construction, maintenance, or incidents. Control zone is also a designated physical area in a smart factory or warehouse where the number of automated guided vehicles (AGVs) or mobile robots is strictly limited.
Convected wave equation – It is also called the convective wave equation. It is a second-order partial differential equation which describes the propagation of acoustic or pressure waves through a medium which s already in motion (a background or mean flow).
Convection – It is the transmission of heat by the circulation of a liquid or gas. It can be natural, with the circulation caused by buoyancy affects because of temperature differences, or forced with circulation caused by a mechanical device such as a fan or pump.
Convection cells – These cells are organized movements of fluid which occur in a heated medium, characterized by the formation of structures such as Benard cells, where warmer fluid rises and cooler fluid descends, facilitating long-distance transport of heat and material within the fluid.
Convection coefficient – It is a proportionality constant which measures how easily heat transfers between a solid surface and a moving fluid (such as a liquid or gas).
Convection effects – These effects refer to the heat transfer process driven by fluid motion, which can be caused by external forces (forced convection) or by density differences resulting from temperature variations in a gravitational field (natural convection). In certain scenarios, both mechanisms can coexist, leading to mixed convection flows.
Convection heat transfer – It is the process of thermal energy moving between a solid surface and a moving fluid (liquid or gas) through a combination of bulk fluid motion and thermal conduction.
Convection heat transfer coefficient – It is a parameter which quantifies the rate of heat transfer between a solid surface and a moving fluid, influenced by factors such as surface geometry, fluid and solid properties, and fluid velocity. It is necessary for calculating the heat flow in convection processes.
Convection loss – It is the transfer of thermal energy away from a hot surface into a moving fluid (such as air or water). It represents unwanted heat escaping from a system to its ambient environment.
Convection roll – It is also called convective roll. It is an organized, quasi-two-dimensional, rotating flow pattern in a fluid (liquid or gas) driven by density and temperature gradients.
Convection velocity – It refers to the speed and direction at which coherent flow structures (such as vortices, turbulence eddies, or thermal / chemical patterns) are carried downstream by the bulk motion of a fluid.
Convective – It means relating to or caused by convection, the transfer of heat and mass through the physical movement of a fluid (such as air or water). It is the process of heat transfer in fluids, where heat stored in a fluid particle is carried to another location, resulting in either heat loss to cooler air or heat gain from warmer air. It is influenced by factors such as air movement and temperature differences between the body and surrounding environment.
Convective boiling – It is also known as flow boiling or forced convection boiling. It is a heat transfer process where a liquid flows through a heated channel, tube, or over a surface through an external force (such as a pump or fan) while undergoing phase change into vapour. Unlike pool boiling, where the liquid is relatively stagnant and motion is driven only by natural buoyancy currents, convective boiling combines forced fluid motion, convective heat transfer, and bubble dynamics.
Convective boundary layer – It refers to the region of a fluid adjacent to a solid surface where heat, momentum, and mass transfer occur through buoyancy-driven or forced-convective fluid motion.
Convective cell – It is a distinct, circulating pattern of motion within a fluid medium (liquid or gas) which is driven by temperature-induced density differences. When a portion of fluid is heated from below, it expands, becomes less dense, and rises. As it reaches a cooler area near the top, it loses heat, contracts, becomes denser, and sinks back down. This continuous cycle creates a self-sustaining loop of rising warm currents and falling cold currents.
Convective coefficient – It is defined as a parameter which quantifies the rate of heat transfer by convection, which is typically determined through informed estimates or correlations of experimental data rather than being a fixed value.
Convective drying – It is a mass and heat transfer process where hot gas or air flows over or through a wet material to evaporate and carry away moisture. It is a process where heat is transferred from a drying medium, typically air, to materials, while simultaneously transporting moisture from the interior of the solid product to its surface, where it is removed by the moving air stream. This process is influenced by factors such as air velocity, temperature, and water concentration differences.
Convective effect – It refers to the transfer of thermal energy (and mass or momentum) through the macroscopic movement and circulation of a fluid, such as a liquid or a gas, combining both advection (bulk fluid motion) and thermal diffusion (random molecular motion).
Convective field – It refers to the spatial flow structure and physical domain (velocity, temperature, or concentration fields) which arises within a fluid when transport is driven by bulk fluid motion, temperature gradients, or concentration differences.
Convective flow – It is the movement of thermal energy and mass through a fluid (liquid or gas) through the bulk motion of the fluid combined with molecular diffusion.
Convective flux – It is the rate of transport of a physical quantity, such as heat, mass (solutes), or momentum, carried across a given surface area by the macroscopic motion of a fluid.
Convective flux Jacobian – It is the matrix of first-order partial derivatives of the convective flux vector with respect to the conserved state vector.
Convective heat transfer – It is the transport of thermal energy between a solid surface and a moving fluid (liquid or gas) driven by the combined effects of fluid motion and thermal conduction.
Convective heat transfer coefficient – It measures the rate of heat transfer between a solid surface and an adjacent moving fluid per unit surface area per unit temperature difference. It is defined by Newton’s law of cooling.
Convective loss – It is the rate of thermal energy transferred and lost from a hot solid surface to a moving fluid (such as air or water) which flows across it.
Convective stage – It is also called convection stage. It mainly refers to the final phase of the metal quenching process, which is a rapid heat treatment technique used to harden metals. It can also refer to the fluid dynamics phase governing heat and mass transport during liquid metal solidification.
Convective transport – It is the movement of mass, momentum, or thermal energy (heat) from one location to another through the bulk motion of a fluid (liquid or gas). Convective transport is pressure-driven flow (in processes like reverse osmosis, ultra-filtration, or nano-filtration) or electrical current (in electro-chemical cells and corrosion) which pushes solutes or ions toward the active interface.
Convective velocity – It is the difference between material velocity and mesh velocity, representing the movement of a material within a mesh framework in the arbitrary Lagrangian-Eulerian (ALE) formulation.
Conventional activated sludge – It refers to a widely used standard technology for municipal wastewater treatment which involves a sequence of processes including preliminary treatments, main sedimentation, an activated-sludge reactor, and secondary sedimentation, primarily aimed at removing organic matter and some nutrients.
Conventional activated sludge process – It is a common wastewater treatment technology which utilizes bio-degradation by activated sludge, which is then separated by sedimentation to remove soluble and colloidal organic compounds and nutrients. Conventional activated sludge process (CASP) has demonstrated a removal efficiency of up to 98 % for microplastics (MPs), though this efficiency can vary significantly.
Conventional activated sludge (CAS) system – It is a standard biological wastewater treatment process which uses suspended aerobic microorganisms (bacteria and protozoa) to break down organic matter and remove pollutants.
Conventional average – It typically refers to the arithmetic mean, the sum of all data points, measurements, or values divided by the total number of items.
Conventional bioreactors – These are well-stirred vessels or bubble columns which facilitate aeration and mixing for biological processes, with stirred vessels achieving higher mass transfer rates because of the improved stirring power, particularly important for fermentations with higher viscosities.
Conventional bitumen – It is a petroleum-derived binder mainly produced from oil processing, which is normally used in asphalt formulations. It is characterized by its performance and properties, but is subject to price fluctuations associated with crude oil supply.
Conventional camera – It is an optical-electronic system designed to map the spatial reflectance and luminance properties of a three-dimensional (3D) scene into a two-dimensional (2D) digital or analog representation.
Conventional cement – It is typically represented by ordinary Portland cement (OPC). It is a fine, inorganic, powdered hydraulic binder which sets and hardens through a chemical reaction with water called hydration.
Conventional coal – It refers to standard, pulverized or stoker-fired coal used in traditional combustion systems, mainly sub-critical or super-critical steam Rankine cycle power plants, to produce high-pressure steam which drives turbine generators.
Conventional coal-fired power plants – These are power generating systems which convert the energy of coal into electricity, mainly using the steam Rankine thermodynamic cycle, which involves the production of steam to drive turbines that generate mechanical work.
Conventional closed-die forging – it is also called impression-die forging. It is a metal-forming process where a heated metal work-piece is compressed between two engraved dies which contain a precise, pre-shaped cavity. The metal is enclosed by the die walls and forced to flow laterally and vertically under high pressure to fill the exact negative impression of the desired shape.
Conventional closed-die titanium forging – it is a hot-deformation process where a titanium work-piece is compressed between two matching matrix dies to produce a highly refined, net-shape component. Unlike isothermal forging, conventional forging utilizes dies which are considerably cooler than the titanium work-piece, creating unique metallurgical challenges and characteristics.
Conventional composite – It is a macroscopic structural material made by combining two or more distinct constituent phases, a continuous matrix phase and a dispersed reinforcement phase, which remain physically separate yet work together to create properties superior to the individual components.
Conventional composite resin – It is a multi-phase structural or restorative material made of a continuous polymer matrix (such as an organic resin) reinforced with dispersed inorganic fillers or fibres linked together by a coupling agent.
Conventional controlled rolling – It is a thermo-mechanical processing method which combines controlled plastic deformation and precise temperature management to refine grain structure and improve mechanical properties in steel without extra heat treatment.
Conventional control system – It is an arrangement of physical devices, electrical circuits, or mechanical components which manages, directs, or regulates the behaviour of another system or process to achieve a desired output.
Conventional conveying system – It refers to a standard mechanical or pneumatic set-up designed to continuously transport bulk or discrete materials from one point to another along a fixed path.
Conventional coring – It is a technique used to cut and retrieve a continuous, cylindrical rock sample (a core) from a sub-surface formation. It is a technique used to get full-diameter core samples from competent formations for laboratory testing of the productive formation.
Conventional crude oil – It is liquid petroleum extracted from underground reservoirs using traditional drilling and pumping methods, where natural formation pressure or standard mechanical lift allows the oil to flow smoothly to the surface.
Conventional cycle – It is a standard, established sequence of thermodynamic processes where a working fluid repeatedly undergoes compression, heat addition, expansion, and heat rejection to convert thermal energy into mechanical or electrical work, returning to its initial state at the end of the loop.
Conventional deliverability test – It is also known as a back-pressure test or flow-after-flow test. It is a well evaluation procedure used to measure a gas or oil well’s production capacity against varying wellhead back-pressures. It is a method for testing gas wells which involves gauging the well’s ability to flow against different back pressures, typically conducted by measuring stabilized bottom-hole flow pressures at different constant flow rates.
Conventional dies – These are specialized, high-precision tools used in manufacturing to cut, shape, and form sheet metal into specific geometry using a mechanical press. Unlike modern progressive or transfer dies which perform multiple operations sequentially in one unit, a conventional die typically performs just one or two specific operations per press stroke.
Conventional diesel combustion – It is a compression-ignition process in an internal combustion engine where liquid fuel is injected into hot, high-pressure compressed air inside the cylinder, auto-igniting as a heterogeneous diffusion flame without a spark plug.
Conventional dimensioning – It is also called traditional dimensioning or coordinate dimensioning. It refers to a method of specifying a part’s size and location using linear measurements and plus-or-minus (+/-) tolerances. Unlike modern geometric dimensioning and tolerancing (GD&T), which controls the exact geometric form, orientation, and relationship between features, conventional dimensioning relies entirely on a rectangular, grid-like system of distances.
Conventional drawing – It is a standardized technical document that uses universal symbols, line types, and orthographic projections to precisely communicate the geometry, dimensions, and manufacturing instructions for a physical part.
Conventional electrode -It is a standard conductive component, such as an Ag / AgCl (silver / silver chloride) sensor or porous half-cell, which interfaces between an external electrical circuit and a physical medium, electrolyte, or human skin.
Conventional energy – It refers to power produced from traditional, finite, and non-renewable resources which have been widely and continuously used for large-scale industrial and grid operations.
Conventional engine – It typically refers to a standard internal combustion engine (ICE) which burns fossil fuels, such as gasoline or diesel, within a closed cylinder to convert chemical energy into thermal energy and then into mechanical work.
Conventional equipment – It refers to traditional, established, and standard machinery, tools, or systems which have been widely used for decades before the advent of modern, automated, or non-conventional (advanced) technologies.
Conventional extrusion – It is also called canned extrusion. It is a metallurgical process used to extrude difficult, hazardous, or reactive materials by sealing the billet inside a protective metal jacket (the ‘can’) before pressing it through a die.
Conventional extrusion process – It is a manufacturing technique where raw material, such as metal, plastic, or rubber, is forced under high pressure through a specially shaped opening called a die to create a continuous, uniform cross-sectional profile (like rods, tubes, or sheets).
Conventional fibre – It refers to a natural or standard synthetic fibre mainly used for traditional textiles, apparel, ropes, and basic manufacturing.
Conventional filtration – It is a standardized treatment train which removes suspended solids, colloids, and pathogens by passing water through a granular media bed (such as sand or anthracite). It is a water treatment process mainly aimed at removing particulates from drinking water, involving steps such as the addition of coagulant chemicals, flash mixing, coagulation-flocculation, sedimentation, and filtration, followed by disinfection before distribution.
Conventional finishing process – It refers to traditional mechanical methods used to refine the surface quality, dimensional accuracy, and texture of a manufactured part.
Conventional forging – It is a forging characteristic by design complexity and tolerances which falls within the broad range of general forging practice. Conventional forgings have less machine stock and tighter tolerances than blocker-type forgings but nee additional production costs, both for the additional die set and for additional forging fabrication steps required to produce this type.
Conventional glass – It is frequently referred to as standard or annealed glass. It is a brittle, amorphous solid, lacking a long-range periodic atomic lattice, formed by rapidly cooling molten silicate-based mixtures (mainly silica, soda ash, and limestone) without crystallization.
Conventional grinding – It is an abrasive machining process which uses a high-speed rotating grinding wheel composed of bonded abrasive grains (typically aluminum oxide or silicon carbide) to shear microscopic layers of material from a work-piece.
Conventional hot rolling – In conventional hot rolling, the reheating, rough rolling, and finish rolling all occur at the highest possible temperatures. The main goal of conventional hot rolling is to optimize productivity. In conventional hot rolling of high-temperature materials, such as titanium and nickel alloys, the hot metal is deformed between cold or warm rolls. This causes chilling on the surface of the rolled metal, resulting in higher working loads and stresses than are needed if chilling is to be avoided. Further, chilling limits the maximum possible reduction per pass and the minimum thickness attainable in conventional hot sheet rolling. From a materials viewpoint, conventional hot rolling frequently needs rolling temperatures which are higher than optimal, which cause more work-piece contamination and can result in micro-structure and property variations in rolled products. To overcome some of the problems associated with conventional hot rolling, the techniques of isothermal and near-isothermal hot rolling have been developed.
Conventional house – It is a residential structure built using traditional, on-site construction methods rather than factory-made or pre-engineered components.
Conventional hydrostatic extrusion – It is a metal-forming process where a pressurized liquid medium inside a sealed chamber forces a billet through a die. Unlike traditional extrusion, where a solid mechanical ram makes direct contact with the work-piece, hydrostatic pressure surrounds and pushes the entire surface of the billet.
Conventional machining – It is a subtractive manufacturing process which removes unwanted material from a work-piece in the form of small fragments called chips using a hard physical cutting tool.
Conventional magnetron – It is a high-vacuum, crossed-field electron tube which converts direct-current (DC) electrical power into high-power alternating-current (AC) microwave radiation.
Conventional manufacturing process – It refers to traditional methods, mainly subtractive machining, casting, and bulk deformation, where physical tools make direct contact with a work-piece to shape, cut, or form raw materials into finished parts.
Conventional material – It refers to a standard, mass-produced material with well-established compositions, predictable mechanical properties, and a long history of industrial use.
Conventional membrane – It is a thin, semi-permeable barrier, typically made of solid or polymeric materials, which separates two phases and lets specific molecules or fluids pass through while blocking others.
Conventional membrane material – It is a semi-permeable barrier, very frequently made from synthetic polymers or natural organic compounds, used to selectively separate specific molecules, ions, or suspended particles from a fluid, gas, or liquid phase under a driving force like pressure or concentration.
Conventional method – It is a traditional, widely accepted, and standardized approach which relies on established practices, well-documented theories, and physical tools to solve technical problems or manufacture products.
Conventional milling – It is the milling in which the cutter moves in the direction opposite to the feed at the point of contact.
Conventional network – It is an interconnection of electrical components (such as resistors, inductors, capacitors) and / or active / passive energy sources (voltage or current sources) designed to model or perform an electrical function. In computer and IT (information technology) engineering, conventional network relies on fixed, dedicated, and proprietary hardware appliances, such as physical routers, switches, and firewalls, to handle control and data planes together on each individual device. Conventional nuclear reactor – It is a thermal-fission system which uses traditional nuclear fuel (typically enriched uranium-235) to sustain a controlled chain reaction, generating heat to produce steam which drives a turbine and creates electricity.
Conventional oil – It is crude petroleum which flows naturally or can be pumped to the surface from underground reservoirs using traditional well-drilling and production methods, without needing complex thermal, chemical, or mining improvement.
Conventional op amp (operational amplifier) – It is an electronic component with two differential inputs and an output, characterized by nominally infinite gain controlled by feedback from the output to the negative inverting input, ensuring that the differential input is maintained at zero.
Conventional pinch-type machine – It very frequently referred to as an initial-pinch plate rolling machine. It is a mechanical or hydraulic metal-working tool used to bend flat sheet metal or heavy plates into cylindrical, arc, or conical shapes. The defining characteristic of this machine is its ability to firmly grip (pinch) the metal plate between two vertically opposed rollers to prevent slipping, while a third adjustable offset roller moves upward to bend the material.
Conventional plant – It refers to a specific, single physical location or facility where production, manufacturing, processing, or power generation takes place.
Conventional pneumatic conveying system – It is an enclosed pipeline arrangement which transports dry bulk powders, granules, or pellets using the aerodynamic drag or pressure differential of a blown or sucked gas stream (typically air or inert gas).
Conventional powder metallurgy (P/M) superalloy processing – It is an advanced manufacturing method which creates high-strength, heat-resistant metal components from fine metallic powders rather than melting and casting large ingots.
Conventional power plant – It refers to a facility which generates electrical energy by burning fossil fuels (coal, oil, or natural gas) to produce high-pressure steam which drives a turbine connected to an electrical generator.
Conventional process – It refers to traditional, long-established manufacturing and machining methods which rely on direct physical contact and mechanical energy to shape materials.
Conventional propeller – It is a rotating mechanical device with radiating blades attached to a central hub which converts rotational shaft power into linear thrust to move a vehicle through a fluid.
Conventional quenching – It is a heat treatment process where a metal component is heated to an austenitizing temperature (typically 800 deg C to 950 deg C) and then rapidly cooled using a liquid medium, such as water, brine, or oil, to lock in a hard, wear-resistant micro-structure like martensite.
Conventional reactor – It refers to traditional, standard equipment or systems used to carry out chemical reactions or nuclear fission, as opposed to modern intensified, micro-, or specialized multi-functional designs.
Conventional repair method – It refers to a standard, traditional, and time-tested technique used to restore a damaged, deteriorated, or defective component, structure, or system to an acceptable or original state of functionality. Unlike advanced high-tech or non-destructive innovations (such as high-pressure automated composite wraps or carbon-fibre high-performance retrofits), conventional methods rely on standard craft, manual labour, and traditional materials.
Conventional rolling – It is a metal forming process where a metal stock passes through a pair of rotating rollers which have the same surface velocity, maintaining a neutral point along a line perpendicular to the rolling movement.
Conventional rolling mill stand – It is the structural unit within a rolling mill which houses and supports the rolls used to reduce the thickness or reshape metal products. It is a fundamental component in the rolling process, guiding the metal through several stages of compression and shaping. These stands typically include housing, cap assemblies, rolls that rotate in bearings, and chocks. Besides, the roll stand consists of mill spindles, a pinion stand, a gear reducer and a motor. In case of constant pass line, the roll-stand slides on the surface of the sole plate.
Conventional sheet metal – It is a flat metal stock with a thickness ranging between 0.4 millimeters and 6 millimeters, while materials below 0.3 millimeters fall into micro-sheet forming, and thicker sections (typically above 6 millimeters) are classified as plates.
Conventional silica – It refers to standard, unmodified silicon di-oxide (SiO2), typically porous or amorphous silica particles or gels, used as a base-line stationary phase, filler, or support material.
Conventional solar cell – It is a solid-state, inorganic semi-conductor device which converts light energy directly into electrical energy using the photo-voltaic effect. Conventional solar cells are solid wafer-like semi-conductor structures which absorb sunlight, generating positive and negative electric charge carriers, which are then separated by an internal electric field.
Conventional spring – It is an elastic mechanical component, typically made of metal or alloy, designed to store and release mechanical potential energy, absorb shock, or maintain a force between surfaces by operating strictly within Hooke’s elastic region.
Conventional stations – These are traditional substations that primarily utilize private communication protocols for relay protection, making interoperability and advanced application functions challenging; they rely on standards like International Electrotechnical Commission standard IEC 60870-5-103 for communication and lack integrated information platforms for advanced monitoring and control.
Conventional steam reforming – It is a process which converts light hydro-carbons, mainly methane from natural gas, into a hydrogen- and carbon mono-oxide-rich gas mixture known as syngas.
Conventional steel structure – It is a load-bearing building framework custom-designed and assembled from standard hot-rolled steel sections (such as I-beams, channels, and angles) to meet specific project and load requirements. Unlike pre-engineered buildings (PEBs), which rely on standardized catalog designs and tapered built-up sections, conventional steel structures are engineered from the ground up for complex, heavy, or multi-load environments.
Conventional stereo-lithography – It is an additive manufacturing (3D printing) process which uses ultra-violet (UV) light or a laser to selectively cure and solidify liquid photo-polymer resin layer-by-layer.
Conventional strain – It is the unit of change in the size or shape of a body because of force. The term is also used in a broader sense to denote a dimensionless number which characterizes the change in dimensions of an object during a deformation or flow process.
Conventional stress – It is the intensity of the internally distributed forces or components of forces which resist a change in the volume or shape of a material that is or has been subjected to external forces. Stress is expressed in force per unit area. Stress can be normal (tension or compression) or shear.
Conventional structure – It is a building or system designed from scratch and built using traditional, on-site construction methods. Unlike pre-engineered or modular buildings, which use standardized, factory-manufactured components, conventional structures are custom-tailored to specific architectural and structural demands.
Conventional technique – It refers to a traditional, well-established, and widely accepted method which relies on direct physical contact, standard mechanical energy, or heuristic-based rules and empirical data.
Conventional technology – It refers to traditional, well-established, and standardized methods or processes which have been widely used and proven over long periods.
Conventional transmission electron microscope – It is a scientific instrument which passes a high-energy beam of electrons through an ultra-thin metal or alloy sample to view internal microstructures at near-atomic resolutions.
Conventional tubing – It refers to rigid, straight sections of metal pipe which are screwed or threaded together end-to-end and run into an oil or gas wellbore to convey reservoir fluids to the surface.
Conventional ultrasonic scanning – This method of evaluating steel cleanliness can get size distributions of inclusions larger than 20 micro-meters in solidified steel samples.
Conventional water treatment process – It is a standardized series of physical and chemical unit operations designed to remove suspended solids, colloidal particles, and pathogens from raw surface water to produce safe drinking water.
Converged solution – It is a solution procedure where the largest value of the residuals is less than a specified threshold, indicating that the solution has reached a state where the residuals are effectively zero. It is the numerical result got when an iterative calculation process reaches a steady state where the error, residual values, or displacements fall below a specified tolerance threshold.
Convergence criterion – It is a pre-defined mathematical condition or threshold used to stop an iterative numerical process (such as a simulation or optimization) when the solution has stabilized and further calculations yield negligible change.
Convergence history – It refers to the chronological record or plot showing how a computational algorithm’s error, residual, or solution parameter changes across successive iterations or time steps.
Convergence limit – It is frequently called a convergence tolerance or stopping criterion. It is a user-defined threshold which stops an iterative numerical calculation (such as a computer simulation or finite element analysis) once the changes between successive steps become negligibly small.
Convergence performance – It refers to the ability of an algorithm to reach a solution efficiently, characterized by its speed and quality of convergence to the global optimal solution, as demonstrated by its behaviour across various benchmark functions.
Convergence pressure – It is the constant temperature pressure at which the vapour and liquid equilibrium ratios (K-factors, Ki) of all components in a hydrocarbon mixture converge to unity (Ki = 1). At this specific pressure and temperature, the distinction between the gas and liquid phases vanishes for the mixture (approaching a critical state), meaning (Ki = yi/xi= 1) for every component ‘i’.
Convergence problem – It happens when a numerical solver or iterative simulation fails to reach a stable, balanced solution within the set error limits. Instead of settling on a clear answer, the calculation oscillates, diverges (moves further away), or stops prematurely because residual errors remain too high. Convergence problems refer to issues which arise during circuit simulations when the simulation fails to reach a stable solution, frequently indicated by the output file reporting node voltages and devices which failed to converge. These problems can occur in both large and small circuits and can need methods such as localizing the issue through hierarchical design or using analog behavioural models for trouble-shooting.
Convergence process – It is a procedure where repeated calculations, simulations, or tests gradually get closer to a stable, accurate, or optimal solution. It refers to the iterative calculation procedure used in computational fluid dynamics (CFD) codes to reach a desired level of accuracy in the solution. It involves setting convergence criteria, such as a maximum number of iterations and an absolute residual level, to determine when the solution has reached a satisfactory level. These criteria can vary depending on the problem being solved and the specific computational fluid dynamics code being used.
Convergence proof – It is a mathematical demonstration showing that as a computational grid is refined, or as the number of iterations increases, the numerical solution approaches the exact analytical solution of the underlying differential equations. It guarantees that an engineering simulation or algorithm is accurate, stable, and actually solving the intended physical problem rather than generating mathematical artifacts.
Convergence property – It refers to the characteristic of a numerical method, simulation, or iterative algorithm in which its calculated output approaches the true physical or mathematical solution as parameters are refined (such as decreasing mesh or element size) or as the number of computation steps / iterations increases.
Convergence sub-layer – It is a protocol layer in computer networking and telecommunications which translates data from higher-level protocols into a format which can be processed by a lower-level transport mechanism. It acts as an adaptable translator, ensuring compatibility between mismatched networks.
Convergence tolerance – It is a predefined limit which decides when an iterative numerical simulation or calculation can stop. It marks the acceptable threshold of error where the change between iterations, residual forces, or displacements becomes small enough which the solution is considered stable and accurate.
Convergency – It is the property or state in which a numerical process, simulation, or system approaches a stable, finite limit or a steady state as calculations, iterations, or time progress. In numerical analysis and simulation, it is the point in an iterative computer simulation (like computational fluid dynamics or finite element analysis) where the changes between successive calculation steps become negligibly small. In systems and control engineering, it is a property where a system ‘forgets’ its initial starting conditions over time and moves toward a unique, bounded limit solution. In workflow and testing, it is an indication which repeated test-fix-rerun cycles are no longer turning up new defects across active test scenarios.
Convergent-beam electron diffraction – it is a technique of impinging a highly convergent electron beam on a crystal to produce a diffraction pattern composed of disks of intensity. It is a method for qualitative and quantitative analysis of crystal structures from a disk diffraction pattern, acquired by illumination of a cone-shaped convergent electron beam on a small sample area with a diameter of 10 nana-meters or less. The convergent-beam electron diffraction (CBED) disk displays the intensity distribution corresponding to changes of diffraction conditions (rocking curve). The method enables people to determine not only sample thickness, lattice parameter, crystal symmetry (point group and space group) and characteristics of a lattice defect, but also a crystal structure (refinement of atomic coordinates, Debye-Waller factors, low-order structure factors (potential distribution)). When the large-angle convergent-beam electron diffraction (LACBED) technique is applied, the characteristic feature of a lattice defect is easily and unambiguously identified and the strains (and a dislocation) at interfaces of a multi-layer material are determined with a high accuracy. The use of an energy filter allows people to conduct more accurate structure analysis.
Convergent passage – It is a duct or channel whose cross-sectional area decreases gradually along the direction of the fluid flow. It is very frequently used to increase the velocity of a fluid while reducing its pressure.
Convergent thinking – It is a thought process which moves forward in sequential steps after a positive decision has been made about the idea.
Converging – It is a dedicated segment on roller or wheel conveyors where two independent conveyors harmoniously intersect, ensuring a smooth amalgamation into a singular conveyor path.
Conversion – It normally refers to the process of transforming energy, units, or data from one form to another. This can involve changing the type of energy, the units of measurement, or the format of data for analysis or application.
Conversion architecture – It normally refers to the design approach in signal processing and radio frequency (RF) systems where a high-frequency signal is mixed directly down to base-band or an intermediate frequency without traditional multi-stage super-heterodyne filters.
Conversion coating – It is a chemical treatment which transforms a metal surface into a thin, adherent, and insoluble inorganic compound layer. It is a coating consisting of a compound of the surface metal, produced by chemical or electro-chemical treatments of the metal. Examples include chromate coatings on zinc, cadmium, magnesium, and aluminum, and oxide and phosphate coatings on steel.
Conversion cost – It consists of the resources spent to process material in a single stage, from one type to another. For example, the costs of converting iron ore to hot metal or bauxite to aluminum.
Conversion factor – It is a numerical ratio equal to one which expresses the relationship between two different units of measurement, allowing people to change units without altering the actual physical quantity.
Conversion formula – It is a mathematical expression used to change a measured quantity from one unit system to another, (such as from Imperial to SI (International System of Units) units, or to relate different physical composition scales without altering the actual physical value or magnitude of the quantity.
Conversion function – It is a mathematical, logical, or hardware mapping which transforms a value, signal, unit, or data type from one representation or domain into another while preserving its core meaning or dynamic relationship.
Conversion gain – It is the ratio of the desired output signal power to the input signal power in a mixer, with distinctions between down-conversion and up-conversion mixers based on the specific signals involved. It varies between active mixers, which provide a positive conversion gain, and passive mixers, which typically show conversion loss.
Conversion loss – It is very frequently applied to RF (radio frequency) and microwave mixers. It is the measure of energy conversion efficiency when a signal is translated from one frequency to another. It is the ratio of the input signal power to the desired output signal power, normally expressed as a positive number in decibels (dB).
Conversion matrix – It is an invertible mathematical array which translates or converts the coordinates or components of a vector from one basis (or reference frame) to another within a vector space.
Conversion of units – Unit conversion is the process of changing a measurement from one unit into an equivalent value in a different unit without changing the actual size or quantity.
Conversion press – It refers to a specialized manufacturing machine tool designed to convert, alter, or reconfigure material forms through mechanical pressure, or a standard power press which has been structurally converted to perform a different specialized operation. Very frequently, it specifies high-speed mechanical stamping systems designed for can-making and packaging lines. These presses accept basic aluminum or steel shells and convert them into finished, functional products by forming and integrating features like easy-open tabs or pop-top lids.
Conversion process – It is a systematic method which transforms raw input materials, energy, or data into useful finished products, energy forms, or outputs. Core types of conversion processes are chemical and thermal processes, mechanical and physical processes, biological processes, and manufacturing / industrial processes.
Conversion rate – It is the fraction or percentage of a starting reactant which has been consumed or transformed into products during a chemical reaction. In software engineering, product development, and technical operations (frequently overlapping with digital systems or user-facing platforms), conversion rate is the proportion of users or system interactions which successfully complete a designated goal.
Conversion ratio – It is the proportion of an output quantity or material produced relative to an input quantity or material consumed in a specific process.
Conversion reaction material – It is very frequently referenced in energy storage and battery design. It is a compound which undergoes a complete chemical and structural transformation during electro-chemical cycling, breaking and forming chemical bonds rather than merely inserting ions into a host structure.
Conversion time – It is the total time an analog-to-digital converter (ADC) takes to transform a single analog input signal into a corresponding digital binary output. It starts immediately after the sampling process finishes (through a sample-and-hold circuit) and ends when the final digital word is ready.
Conversion treatment – It is a surface modification process where a metal part is sub-merged in a chemical or electro-chemical solution. Instead of plating or painting a new separate layer on top of the metal, the treatment reacts directly with the metal’s outer surface to transform it into an insoluble, adherent compound layer (such as an oxide, phosphate, or chromate).
Converter – It is a furnace in which oxygen is blown through a bath of molten metal or matte, oxidizing the impurities and maintaining the temperature through the heat produced by the oxidation reaction. Typical converters are basic oxygen furnace and argon oxygen decarburization vessels.
Converter gas – It is also known as LD (Linz-Donawitz) gas. It is a by-product gas produced during the production of liquid steel in a basic oxygen furnace (converter), where impurities of hot metal are oxidized with oxygen gas. The main constituents of converter gas are carbon mono-oxide, carbon di-oxide, oxygen, and nitrogen. Composition wise it is similar to blast furnace gas but with lesser percentage of nitrogen in it. Converter gas is a colourless, toxic, hazardous, and explosive gas.
Converter process – It is a method for converting carbon-rich liquid hot metal into low-carbon crude steel, mainly utilizing the basic oxygen furnace (BOF) process characterized by the injection of pure oxygen and the use of basic refractory lining and slag.
Converter slag – It is a byproduct from steel production which can be used as a soil amendment, providing nutrients such as calcium, iron, silicon, phosphorus, and magnesium, while also neutralizing soil acidity, stabilizing heavy metals, and improving soil quality for agricultural purposes.
Converter transformer – It is a specialized electrical transformer which links an AC (alternating current) power network to a power electronic converter (such as a rectifier or inverter) in high-voltage direct current (HVDC) transmission or large industrial systems. It is a device which interfaces the voltage source converter (VSC) alternating current terminals with an alternating current network, providing electric isolation and filtering, while optimizing the alternating current voltage level to suit the converter valve voltage rating. Its configuration and rating depend on the total system power rating, converter topology, and specified requirements.
Convertible debt – It is a type of debt security which can be converted into equity at a later date, which is considered riskier than straight debt as per the pecking-order theory. This theory suggests that organizations are required to issue straight debt before convertible debt because of the investor perceptions of safety.
Converting process – It is the process which transforms copper matte into blister copper. By reacting the matte with oxygen enriched air and silica slags both the iron and sulphur are removed leaving copper metal of 98 % purity known as blister copper.
Convertor – It is a device, system, or vessel which transforms energy, signals, or materials from one form, state, or specification into another.
Convex face – It refers to a surface or boundary which curves or bulges outward (away from the interior of the object). It is a face which bows or protrudes outward, resembling the exterior of a sphere, circle, or cylinder. In computational geometry and convex analysis, convex face is a face (such as a facet or boundary polygon) of a geometric shape or polyhedral object which satisfies the rules of a convex set.
Convex function – It is a continuous function where the line segment (chord) connecting any two points on its graph lies on or above the curve itself, resembling the shape of a cup or a bowl (concave upward).
Convexity – It is curved such as the outer surface of a sphere. In welding, it is the maximum distance from the face of a convex fillet weld perpendicular to a line joining the weld toes.
Convex lens – It is a transparent optical component (typically glass or plastic) which is thicker in the centre than at the edges and features a positive optical power which converges parallel light rays toward a single focal point.
Convex mirror – It is a curved, spherical reflector with a bulging surface which faces the light source and causes parallel light rays to spread outward. It spreads incoming light beams away from a virtual focal point located behind the mirror surface. It produces images which are always virtual (cannot be projected on a screen), upright (erect), and diminished (smaller than the actual object). It provides a much wider angular field of view compared to flat or concave mirrors. It features a positive focal length and a positive image distance behind the mirror, with a negative object distance in front.
Convex model – It is a mathematical frame-work which represents uncertainty or system behaviour using a convex set of functions, vectors, or parameters rather than precise probability distributions.
Convex optimization problem – It is the task of finding the minimum value of a convex objective function or the maximum of a concave function within a convex set, while adhering to constraints which are also defined as convex functions. Each local optimal point in such problems is guaranteed to be a global optimal point.
Convex polytope – It is a bounded, multi-sided geometric object in a multi-dimensional space which has no curved parts, holes, or dents.
Convex problem – It is an optimization task where one minimizes a convex objective function (or maximize a concave function) over a convex feasible set, meaning all constraint functions are also convex. It is the task of finding the minimum value of a convex objective function or the maximum of a concave function within a convex set, subject to constraints that are also defined as convex functions. In such problems, every local optimal point is guaranteed to be a global optimal point.
Convex set – It is a collection of points where the straight-line segment connecting any two points in the set lies entirely within that set. It is a collection of points such that for any two points within the set, the entire line segment connecting them is also contained within the set.
Convex solution – It refers to an optimal point or set of points found within a convex optimization problem, where the objective function curves upward like a bowl and the feasible region is a convex set.
Convex surface – It is a surface which curves or bulges outward, away from its interior or from a flat reference plane, resembling the outer side of a sphere or a ball.
Conveyed material – It refers to a solid, liquid, powder, granular product, or packaged good which is actively transported, moved, or handled by a mechanical, pneumatic, or gravitational conveying system.
Conveying air – It refers to the gas (typically air) used as a transport medium in a pneumatic conveying which is a system to push, pull, or suspend granular, powdery, or bulk solid materials through a closed pipe-line.
Conveying capability – It refers to a system’s or material’s ability to transport a specific volume, mass flow rate, or type of particulate solid from one point to another over a given distance under defined operating limits.
Conveying condition – It refers to the specific physical, dynamic, and environmental parameters under which bulk materials, fluids, or goods are transported through a system (such as a pneumatic pipeline, mechanical belt, or screw conveyor).
Conveying cycle – It refers to the complete sequence of material intake, transport, and discharge in a batch-operated transport process. Important phases of a conveying cycle are intake / loading, transport, and discharge / venting.
Conveying data – It refers to the specific physical, flow, and operational metrics used to design, scale, and analyze material-transport systems (such as pneumatic or mechanical conveyor lines), or more broadly, the standardized definition of asset and telemetry data in automated industrial control systems.
Conveying distance – It refers to the spatial interval or length between a starting point and a destination when transporting, communicating, or moving something from one location to another.
Conveying limit – It refers to constraints in material transport systems. It defines the operational boundary of a transport.
Conveying line – It is an enclosed pipeline or duct used to transport granular, pulverized, powdery, or bulk solid materials from one point to another using a moving stream of gas (typically air). In conveying line, the inlet air velocity is the superficial air velocity at the point of material entry, ensuring effective material conveying by maintaining a velocity higher than the minimum needed for successful transport.
Conveying line inlet air pressure – It is the absolute pressure of the gas (such as air or nitrogen) measured right at the point where it enters the pneumatic conveying pipe-line. It represents the starting pressure of the carrier gas before it accelerates or interacts with the bulk solids being introduced into the system.
Conveying-line inlet air velocity – It is the superficial air velocity of the gas (air) at the exact point where solid particles or materials enter the pneumatic transport pipeline. It is calculated as the volumetric air flow rate divided by the internal cross-sectional area of the pipe at the material feed point, evaluated using the local pressure and temperature conditions.
Conveying line pressure drop – It is the reduction in static pressure (dP) which occurs between the inlet and outlet of a pipeline as a gas or air-solids mixture flows through it. It represents the main energy variable needed to overcome flow resistance and drive material through a pneumatic or hydraulic transport system.
Conveying performance – It measures how efficiently, reliably, and rapidly a material-handling or pneumatic conveying system transports bulk solids or fluids through a system while managing energy use and product integrity.
Conveying pipeline – It is an enclosed tubular system designed to transport materials, such as liquids, gases, slurries, or bulk solids / powders, from one location to another using fluid dynamics, gravity, or compressed gas.
Conveying surface – It is the operative area of a conveyor system where materials are transported, typically a flat or contoured structure supporting the items being conveyed. Regular inspections are necessary to ensure its integrity, assess wear, and guarantee optimal functionality throughout the conveyor’s operation.
Conveying system – It is a mechanical or pneumatic set-up designed to continuously transport materials, goods, or bulk items from one location to another within a facility, plant, or outdoor site.
Conveying trial – It is an experimental test conducted with a specific bulk material to evaluate how it flows through a transport system, such as a pipeline or conveyor, before full-scale equipment is designed or installed.
Conveyor – It is an equipment or moving belt used to transport goods, packages, or materials from one place to another.
Conveyor belt – It is a perpetually moving band, crafted from diverse materials like fabric, rubber, or metal, facilitating seamless object transport from one location to another. It necessitates routine inspections for wear patterns, alignment, and splicing integrity. It has four components namely (i) carcass or carcase which consists of textile plies, steel weave, or steel cord, (ii) covers which are made up of either rubber or PVC (polyvinyl chloride) of different qualities, (ii) additional components of the conveyor belts which are as needed and are normally edge protection, impact protection, and longitudinal slitting prevention etc., and (iv) special construction elements which are the profiles on steep incline belts, cleats, or corrugated edges etc. The conveyor belts play a major part in the whole belt conveying system and have to overcome several and varied stresses.
Conveyor belt scale – It is a precision-engineered system designed for material weighing on the conveyor belt, mandating recurrent calibrations and checks to preserve and verify accuracy.
Conveyor belt monitoring system – It is based on radiographic technology. It supplies and processes nonstop live information about any deficiencies of a conveyor belt.
Conveyor diverters – These are ingeniously crafted mechanisms for guiding materials away from their current conveyor path to another, demanding regular inspections to ascertain continuous functionality and proper alignment.
Conveyor diverter valve – It is a mechanism which is designed to redirect material flow from one conveyor path to another, prompting periodic inspections to ensure seamless functioning.
Conveyor frame – It is the foundational skeletal structure providing support to the conveyor belt, necessitating periodic scrutiny for alignment precision, structural robustness, and preemptive identification of potential damage.
Conveyor guarding – It is an ensemble of protective barriers and devices strategically positioned to forestall access to moving components of a conveyor system, necessitating routine inspections for compliance and continual evaluation of the effectiveness of these protective measures.
Conveyor idlers – These are rollers or a set of rollers providing support and guidance to the conveyor belt, demanding regular inspections for alignment, wear, and lubrication to ensure efficient operation.
Conveyor impact bed – It is a dedicated component which is designed to absorb the impact of material loading onto the conveyor belt, necessitating frequent inspections for wear and optimal functionality.
Conveyor merge – It is the juncture where materials from diverse conveyors merge into a single flow, needing checks to ensure seamless merging and proper alignment.
Conveyor pallet – It is a specialized flat platform or tray used in automated production and assembly lines to securely hold, position, and transport individual parts or products as they move through different manufacturing or inspection stations.
Conveyor, pneumatic tube – A pneumatic tube conveyor system is an enclosed network which moves items or loose bulk materials through pipes using air pressure or a vacuum. Blowers or compressors push or pull air to transport the contents safely and quickly from one place to another.
Conveyor pulley – It is a rotating cylindrical component guiding and supporting the conveyor belt, demanding routine inspections for wear, balance, and precise alignment to maintain operational efficiency.
Conveyor, roller – Roller conveyor is a material handling system made of parallel cylindrical tubes mounted in a frame which use rolling motion to move items with low friction.
Conveyor, screw – Screw conveyor is a mechanical device which uses a rotating helical blade, called flighting, tube or U-shaped trough. It operates on the principle of the Archimedes’ screw.
Conveyor skid plate – It is a protective plate situated on the underside of the conveyor belt to minimize friction and wear, necessitating periodic inspections to ensure continued effectiveness.
Conveyor skirt board – It is a protective barrier along the sides of the conveyor belt to prevent material spillage, requiring inspections for wear patterns and ongoing effectiveness.
Conveyor, slat – A slat conveyor is a heavy-duty material handling system which uses a continuous chain-driven loop attached to horizontal, flat plates (slats) to transport goods along a fixed path.
Conveyor speed – It is the rate at which materials, items, or the conveyor belt itself travel along a system, typically measured in meters per second or meters per minute.
Conveyor system – It is a mechanical apparatus or a material-handling device designed to move materials, goods, or products continuously along a pre-determined path.
Conveyor transition – It is the section where the conveyor belt shifts from a flat profile to a troughed profile, necessitating checks to ensure smooth material transfer.
Conveyor trough – It is the channel-shaped enclosure housing the conveyor belt, necessitating inspections for material spillage, wear, and alignment to maintain optimal conveyor functionality.
Conveyor walkway – It is an elevated walkway for maintenance personnel along the conveyor’s length, demanding regular inspections for safety and structural integrity.
Convolutional code – It is a type of error-correcting code in digital communication which processes a continuous stream of data bits using a sliding window with memory, producing output code bits based on the current input bit and a sequence of previous input bits.
Convolutional coder – It is a digital logic device used in communication engineering to add forward error-correcting redundancy to a continuous stream of data.
Convolutional coding – It is a type of error-correcting code used in digital communications which adds structured redundancy to a continuous stream of information bits. Unlike block codes, which split data into isolated, fixed-size chunks, a convolutional encoder uses memory (typically a shift register) so that the generated output bits depend on the current input bit as well as a small number of previous input bits.
Convolutional encoder – It is a finite state machine in digital communication and error-control which converts a continuous stream of input message bits into a redundant encoded output stream using shift registers and linear logic operations.
Convolutional layer – It is the core building block of a convolutional neural network (CNN). It applies learnable filters (kernels) which slide across the spatial dimensions of an input (such as an image or sensor grid) to compute dot products and generate feature maps.
Convolutional neural network – It is a specialized type of deep learning feed-forward artificial neural network to process grid-like data, such as images, video, and audio, by using filters to automatically extract spatial features.
Convolution property – It states that the convolution of two signals in the time (or spatial) domain corresponds to the multiplication of their respective transforms (such as the Fourier, Laplace, or Z-transform) in the frequency domain, and vice versa. This property transforms complex calculus operations into simple algebraic multiplications.
Convolution sum – It is a mathematical operation used to find the output response of a discrete-time linear time-invariant (LTI) system when given an arbitrary input sequence and the system’s impulse response.
Convolution theorem – It states that the convolution of two signals or functions in the time (or spatial) domain is equivalent to the pointwise multiplication of their respective transforms in the frequency domain, and vice versa.
Co-occurrence matrix – It is very frequently known as a gray-level co-occurrence matrix (GLCM). It is a square matrix which records how frequently pairs of pixel intensity values (gray levels) appear in a specific spatial relationship (distance and angle) within an image.
Cook model – It is known as the Johnson-Cook model. It is defined as a mathematical representation used to model the strength behaviour of materials under large strains, high strain rates, and high temperatures, particularly in scenarios involving intense impulsive loading. It incorporates parameters such as yield stress, effective plastic strain, and temperature effects to predict material performance under extreme conditions.
Coolant – It is a material such as water or pressurized gas which transfers heat from the core. In case of grinding, it is the liquid used to cool the work during grinding and to prevent it from rusting. It also lubricates, washes away chips and grits, and aids in getting a finer finish. In metal cutting, the preferred term is cutting fluid.
Coolant accident – It is known as loss of coolant accident (LOCA). It is an initiating event which can lead to substantial release of fission products into the environment because of the failure in the main coolant system of a nuclear reactor.
Coolant flow – It refers to the continuous movement of a liquid or gas medium through a mechanical, nuclear, or manufacturing system to absorb, carry away, and dissipate thermal energy.
Coolant loss – It refers to the reduction in the volume of liquid coolant inside a closed thermal or mechanical cooling system.
Cooled condenser – It is a type of heat exchanger which removes heat from a high-temperature vapour to convert (condense) it back into a liquid state.
Cooled fast reactor – It is also called fast-neutron reactor. It is a type of nuclear reactor which sustains a chain reaction using unmoderated, high-energy (fast) neutrons without a neutron moderator like water to slow them down, using a non-moderating coolant to remove heat from the core.
Cooled gas – It refers to a gas whose temperature has been reduced intentionally through heat transfer, phase change, expansion, or contact with a cooling medium.
Cooled lance – It is frequently a water-cooled oxygen lance. It is a heavy-duty tubular device used to inject high-speed oxygen, fuels, or process gases directly into a molten metal bath or furnace.
Cooled nuclear reactor – It is a thermal or fast reactor system which uses a circulating fluid (liquid, gas, or liquid metal) to absorb heat generated by nuclear fission in the core and transfer it to a power-conversion or steam-supply system.
Cooled reactor – It is a nuclear or thermal system which uses a circulating fluid (such as water, gas, or liquid metal) to absorb and transfer thermal energy away from the reactor core, preventing overheating and driving power-conversion equipment like steam turbines.
Cooled sample – It normally refers to a process fluid sample (such as high-pressure steam, hot liquid, or gas) which has been lowered in temperature and pressure through a specialized heat exchanger, known as a sample cooler, to ensure safe collection, prevent flashing (sudden boiling), and preserve chemical integrity for laboratory analysis. A cooled sample can also refer to a sample rapidly quenched from a molten state (such as an aluminum-copper-magnesium alloy sucked into a cold copper mould) to achieve high cooling rates and freeze a specific microstructural phase.
Cooled sensor – It is a measuring or imaging device, very frequently an infrared or thermal detector, which integrates an active internal cooling system (such as a cryogenic cooler or fluid channel) to lower its operating temperature down to cryogenic levels (typically 80 Kelvin to 110 Kelvin), reducing thermal noise and increasing sensitivity.
Cooled slag – It is the solid, non-metallic by-product left over after molten slag, formed during metal smelting or refining processes like iron, steel, or copper production, is allowed to cool and solidify. The properties and engineering uses of cooled slag depend heavily on how fast it is cooled. Types of cooled slag are air cooled slag. Quenched / granulated slag, and expanded (foamed) slag.
Cooled syngas – It is synthesis gas (a mixture of carbon mono-oxide and hydrogen) which has undergone a cooling process to lower its temperature after being produced in a high-temperature gasifier. This cooling step is important to recover energy and prepare the gas for downstream purification and processing.
Cooler – It is a specialized device or system used to remove intense heat from industrial furnaces, molten metals, or processed components to control material micro-structures, protect equipment integrity, or manage ambient plant temperatures.
Cooler liquid – It refers to fluids, such as water or oil, utilized in thermal management systems for effective heat dissipation in applications like electronic cooling and battery thermal management, improving temperature uniformity and efficiency.
Cool exhaust gas – It refers to exhaust gases which have been cooled, typically through the use of coolant, to reduce thermal throttling and lower nitrogen oxide (NOx) emissions in engine systems. This cooling process can involve the strategic throttling of coolant flow in the exhaust gas recirculation (EGR) loop.
Coolidge process – It is an early, foundational powder metallurgy technique used to manufacture ductile tungsten wire. TIis revolutionary process solved a major industrial hurdle. Tungsten possesses the highest melting point of any metal (3,410 deg C), making it impossible to melt and cast using traditional metallurgical methods. The Coolidge process has transformed brittle tungsten powder into a highly ductile, workable metal which could be drawn into extremely thin, durable filaments for incandescent lightbulbs and early X-ray tubes.
Cooling – It is the process of removing thermal energy from a system, machine, or environment to lower its temperature or cause a phase change.
Cooling acceleration effect – It is frequently referred to as ‘accelerated cooling; (ACC) or forced cooling. It refers to the thermodynamic and microstructural changes which occur when a metal is cooled at a rate considerably faster than conventional air cooling. By accelerating the cooling rate, metallurgists bypass equilibrium phase transformations, allowing them to precisely control grain size, suppress undesired phases, and manipulate final mechanical properties. In industrial practice, this is known as ‘alloying with water’, since it allows steel to achieve high strength and toughness using a leaner chemical composition with fewer expensive alloying elements.
Cooling air – It is a thermal management method which uses ambient or conditioned air as a medium to absorb and dissipate unwanted heat from machinery, electronics, or industrial processes. It relies mainly on convective heat transfer, moving cooler air across hot surfaces or through heat exchangers to lower system temperatures.
Cooling and equalizing loop – The material entering the no twist block is required to be intensively cooled for final rolling at low temperatures. This is then to be followed by a sufficiently long equalizing section to allow the metallurgical properties to be achieved uniformly over the cross section of the finished wire rods. Without equalization section, the temperature difference between surface and core can be so large that different micro-structures can be created during the subsequent forming process. On the other hand, there are steel grades which are required to be rolled as hot as possible and for which a long equalizing section leads to deterioration in quality. The loop technology allows these two demands to be perfectly reconciled. The material from the intermediate train can take the short direct route or the route through the loop with additional water boxes and long equalizing sections before being rolled in no-twist blocks.
Cooling atomic reactors – It is the continuous, thermodynamic process of removing intense thermal energy from a nuclear reactor core to prevent the melting of structural materials and to transfer that heat for power generation. The cooling process is strictly governed by the thermal and mechanical limits of the reactor’s structural metals and alloys.
Cooling bed – A cooling bed is part of a rolling mill located at the end of the rolling mill. Cooling bed is the equipment where rolled products are cooled and at the same time item-by-item transferred to the roller table, on which they are transported to the finishing section. It supports and permits the hot rolled products from the last stand of the rolling mill to cool. Cooling bed naturally cools the material as well as cross transfers towards the discharge end. In a cooling bed the temperature of the entire length of the bar is to cool at the same time. If not, it develops stresses in the bar.
Cooling bed dividing shear – It is used to cut cooling bed lengths. This shear is normally designed for low surface temperatures. This shear is normally installed before entry to cooling bed. The cooling bed shear is normally either stop / start shear or continuous operating type. It is driven by the direct current motor drive. This shear is also normally controlled through programmable logic controller system and hence very close tolerance of cut length is achieved.
Cooling capacity – It is the maximum rate at which an HVAC (heating, ventilation and air conditioning) or refrigeration system can remove heat from an enclosed space or process stream over time. It is measured in watts (W), kilowatts (kW), or tons of refrigeration.
Cooling channel – It is an internal passageway machined, cast, or 3D-printed into a tool, mould, die, or mechanical component to circulate a fluid (such as water or oil). Its core purpose is to absorb and remove excess heat, control thermal gradients, and regulate operating or solidification temperatures.
Cooling characteristics – These characteristics define how a heated metal cools down over time when exposed to a specific cooling medium. These characteristics determine the final micro-structure, mechanical properties, and hardness of the metal.
Cooling coil – It is a finned-tube heat exchanger which removes sensible heat and moisture from an air stream. As warm air passes over the cold surface, the internal fluid absorbs the heat, lowering the air’s dry-bulb temperature and condensing out water vapour.
Cooling condition – It refers to the specific environment, method, and rate at which a heated or molten metal sheds thermal energy to return to a lower or ambient temperature. It is a critical parameter in heat treatment and casting since it directly controls phase transformations, grain size, and the final mechanical properties (such as hardness and ductility) of the material.
Cooling, controlled – Controlled cooling is a managed thermal process where hot or molten metal is cooled at a specific, pre-determined rate. This precise regulation shapes the internal crystal structure, eliminates internal stresses, and achieves target mechanical traits like hardness, strength, and ductility.
Cooling conveyor – It is a specialized conveyor system which is designed to cool materials during transportation, necessitating checks for cooling mechanisms and the condition of the conveyor belt.
Cooling curve – It is a graph showing the relationship between time and temperature during the cooling of a material. It is used to find the temperatures at which phase changes occur. A property or function other than time can occasionally be used, e.g., thermal expansion.
Cooling curve analysis – It is a graphical technique which plots the temperature of a metal or alloy against time as it cools from a molten state, revealing key phase transformation temperatures and solidification behaviour.
Cooling curve test – It is a graphical measurement of temperature over time as a metal or liquid quenchant cools down. It is used to determine phase transformations or evaluate the cooling performance of quenching media.
Cooling cycle – It is a thermodynamic process which removes heat from a low-temperature space and rejects it to a higher-temperature environment using a circulating refrigerant. Majority of the mechanical systems rely on the vapour-compression cycle, which uses four core parts namely a compressor, a condenser, an expansion device, and an evaporator.
Cooling data – It refers to the quantitative metrics, thermal parameters, and fluid-dynamics data used to design, monitor, and manage heat removal systems. This includes tracking temperatures, airflow rates, power densities, and fluid flows to keep equipment within safe operating limits.
Cooling degree day – It is a metric used to measure how much and for how long the outdoor air temperature rises above a specific base temperature (typically 20 deg C), indicating the cooling demand needed to keep a building comfortable.
Cooling degree hours – It is a metric which measures the magnitude and duration of outdoor air temperatures exceeding a building’s base (balance-point) temperature. It is calculated by summing the hourly temperature differences (outdoor dry-bulb temperature minus the base temperature) for each hour the outdoor temperature is higher than that baseline.
Cooling device – It is a system or component designed to absorb, manage, and dissipate excess thermal energy from machinery, electronics, or structures. It maintains safe operational temperatures to prevent component failure, material degradation, or thermal drift.
Cooling drag – It is the aerodynamic resistance caused by air passing through an engine or vehicle cooling system. It results from the momentum change of the internal airflow and the external pressure disturbances created around the inlets and exhausts.
Cooling effect – It is the physical process where heat is removed or absorbed from a system, component, or environment, resulting in a temperature drop. It is achieved through mechanisms like evaporative cooling, conduction, convection, radiation, or refrigeration cycles to protect equipment and maintain efficiency.
Cooling factor – It normally refers to a thermodynamic parameter, material property, or environmental variable which determines the cooling rate of a metal during casting, welding, or heat treatment. The cooling rate is mathematically defined as the slope of the cooling curve (dT/dt), indicating how quickly a metal’s temperature drops over time.
Cooling fin – It is an extended surface attached to a heat-producing object to increase the rate of heat dissipation. It works by moving heat away from the source through internal conduction and releasing it into the surrounding fluid (normally air) through improved surface convection.
Cooling fraction – It is the ratio of the cooling air needed to the exhaust gas flow in a turbine, influenced by factors such as combustion temperature and compressor pressure ratio. It represents the proportion of cooling air needed to maintain allowable blade metal temperatures during operation.
Cooling hole – It is a precision-engineered opening in high-temperature components, such as gas turbine blades, aero-engines, and combustion liners, which channels cooler air from an internal source to form a protective thermal boundary layer across the exterior surface (a process known as film cooling).
Cooling intensity – It measures the rate and effectiveness of heat removal per unit of area or volume during a thermal process. It is mainly governed by the local heat transfer coefficient and temperature gradient between a hot surface and the cooling medium.
Cooling lubrication – It is the use of specialized fluids, such as oils, water, or emulsions, to simultaneously reduce friction, wear, and mechanical stress between moving parts while dissipating thermal energy generated during machinery operation or metal-cutting processes.
Cooling performance – It is the measure of how effectively a system removes thermal energy from a space, fluid, or component relative to the energy or work it consumes. It is normally evaluated using metrics like the coefficient of Performance (COP), cooling capacity, and temperature differentials (dT).
Cooling portion – In rotational moulding, it is the phase of the manufacturing cycle which starts when the mould leaves the oven and ends when the finished part is removed. It is the time frame where the polymer part solidifies inside the mould after heating, prior to demoulding. In thermal or HVAC (heating, ventilation and air conditioning) systems, it refers to the fraction of a cycle, load, or flow dedicated to heat removal. In cooling towers and water systems, it refers to the fraction of circulating water which is intentionally vapourized to reject heat, or the blowdown portion managed to control mineral concentrations.
Cooling power – It typically refers to the electrical input power consumed by a cooling system (like a chiller or air conditioner) to drive its operation, though it can also describe the rate of heat removal (cooling capacity). It is also the thermal response of the quenchant or the rate of the heat removal from a sample which is normally instrumented.
Cooling practice – It refers to the strategic application of thermodynamic and heat transfer principles to safely remove excess thermal energy from a device, machine, or structural system. Its main goal is to maintain optimal operating temperatures, ensuring peak performance, energy efficiency, and equipment longevity.
Cooling rate – It is the average slope of the time-temperature curve taken over a specified time and temperature interval. It is the slope of the cooling curve (dT/dt), indicating how quickly a metal’s temperature drops over time.
Cooling scheme – It is a planned method or structural layout used to transfer and remove excess heat from a system, device, or process. It keeps operating temperatures within safe, efficient limits using heat transfer agents like air, water, refrigerants, or specialized coolants.
Cooling sequence – It refers to the timed, ordered series of events or rate of temperature reduction executed to safely and efficiently remove heat. Depending on the discipline, it means either the staged activation of mechanical equipment (like chillers and cooling towers) or the controlled thermal ramp-down of a material during manufacturing.
Cooling speed – It is the rate at which a material’s or system’s temperature decreases over time, typically measured in degrees Celsius per second or minute. It dictates how internal micro-structures, grain sizes, and mechanical properties form during processes like heat treatment.
Cooling stages – These refer to the specific, sequential phases of temperature reduction which control a metal’s internal structure and final mechanical properties. Cooling stages very frequently defines the three distinct phases of fluid heat transfer during rapid quenching, or the macro-stages of structural transformation on a standard cooling curve. When a hot metal component is submerged into a liquid quenchant (like water, oil, or polymer), heat is extracted through three distinct, physical stages namely vapour blanket stage (vapour phase), nucleate boiling stage (boiling phase), and convective stage (liquid cooling phase).
Cooling staves – They are also called cooling plates. A stave is a cooling device having one or more water channel, and is installed in numbers on the inner surface of the blast furnace to protect its steel shell and maintain the inner profile. The staves are conventionally made of cast iron but in high heat flux zones of the blast furnace now copper staves are also being used.
Cooling storage – It is frequently called cold thermal energy storage (CTES) or cool storage. It refers to systems which generate and store cooling capacity (such as chilled water or ice) during off-peak hours to meet thermal or air-conditioning loads during peak demand periods.
Cooling stresses – These are the residual stresses in castings resulting from non-uniform distribution of temperature during cooling.
Cooling tower – It is a specialized heat exchanger in which air and water are brought into direct contact with each other in order to reduce the water’s temperature. As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower.
Cooling utility – It is a centralized or distributed resource, such as cooling water, chilled water, air, or refrigerants, supplied to an industrial process to absorb and remove unwanted heat.
Cooling valve – It is a mechanical or automated device used to regulate, mix, divert, or isolate the flow of a cooling medium, such as water, chilled fluid, air, or refrigerant to keep machinery, engines, or HVAC (heating, ventilation and air conditioning) systems within safe operational temperature limits.
Cooling water – It is used for the purpose of cooling. Cooling water is normally classified as either non-contact or indirect cooling water and contact or direct cooling water. Indirect cooling water application is the use of water for general cooling purposes where only equipment is being cooled and the water does not contact the material in process, off gases or fluids. Direct cooling water includes all applications of water where water comes in direct contact with material in process, process gas cleaning applications, process fluid applications (oils, cleaners, etc.) and rinse applications. Direct cooling waters are subject to treatment for recycling.
Cooling zone – In this zone of the kiln, lime which leaves the calcining zone at temperatures of 900 deg C, is cooled by direct contact with ‘cooling’ air, part or all of the combustion air, which in turn is preheated. Lime leaves this zone at temperatures of less than 100 deg C.
Cooperating robot – It is an industrial machine which works in tandem with humans or other robots using safety sensors and virtual or physical boundaries. It bridges traditional isolated industrial robots and direct-contact collaborative robots (cobots).
Cooperative diversity – it refers to the diversity got through user cooperation, where users assist each other by relaying their partners’ data, thereby improving reliability and performance in communication systems.
Cooperative fuel research – It refers to a standardized testing method used to determine the research octane number (RON) and motor octane number (MON) of fuels through specific engine tests. This method is necessary for assessing engine knock resistance and overall fuel performance under controlled conditions.
Cooperative mode – It refers to an operational setup where multiple agents, nodes, or processes voluntarily share resources and coordinate actions to achieve a common goal, rather than competing or operating in isolation.
Cooperative multi-point – It refers to techniques which coordinate multiple transmit points (TPs) to improve data rates and spectral efficiency for cell edge users in LTE (long term evolution) and long term evolution advanced systems. Cooperative multi-point (CoMP) involves coordinated scheduling and beam-forming, joint transmission, and transmit point selection to improve received signal quality and mitigate interference.
Cooperative network – It is a communication system where multiple nodes or devices share resources, power, and relay signals for one another. By acting as virtual antennas or relay stations, these nodes improve data speed, expand coverage, and reduce signal loss in wireless and distributed environments.
Cooperative positioning – It is a navigation and state-estimation technique where multiple connected devices, vehicles, or robots share local measurements, relative distances, and status data to calculate their positions more accurately than they can alone.
Cooperative spectrum sensing – It is a process in cognitive radio networks where multiple secondary (unlicensed) users collaborate to detect the presence or absence of a primary (licensed) user. By sharing and combining their individual sensing data, they overcome channel impairments like multipath fading, shadowing, and hidden terminal problems.
Cooperative transmission – It is a wireless communication technique where multiple spatially separated nodes or devices work together to relay a source message. By forming a virtual antenna array, these nodes leverage spatial diversity and physical layer combining to improve signal quality, extend range, and save power.
Coordinated multi-point – It is a wireless technique where multiple geographically separated base-stations or antenna nodes work together to transmit or receive signals. It turns neighbouring cells into a cooperative group to reduce interference and boost speeds for users at cell edges.
Coordinated scheduling – It is a multi-cell or multi-system resource allocation method. It allows distinct nodes or infrastructure to communicate and align decisions. This minimizes interference, optimizes performance, and balances shared loads across networks, power grids, or production lines.
Coordinated universal time (UTC) – It is the primary international time standard maintained by a weighted average of hundreds of atomic clocks worldwide.
Coordinate geometry – It is also called analytic geometry. It is a branch of mathematics which uses a grid of numbers and algebraic equations to define, locate, and analyze geometric shapes. Coordinate geometry (frequently expanded to 3D with ‘x’, ‘y’, and ‘z’ axes for width, length, and elevation) is used to give every physical point on a project a precise numerical address. It converts physical dimensions, structures, and land contours into mathematical models, allowing engineers to calculate exact stresses, paths, angles, and material layouts.
Coordinate measuring machines – These machines are used to inspect the dimensions of a finished product. Coordinate measuring machines consist of the machine itself and its probes and moving arms for providing measurement input, a computer for making rapid calculations and comparisons based on the measurement input, and the computer software which controls the entire system. Coordinate measuring machines are mainly characterized by their flexibility, being able to make several measurements without adding or changing tools.
Coordinate scale – It is the ratio between a grid or coordinate distance and the true measured ground distance. It corrects distortions which occur when projecting curved earth surfaces or mathematical models into flat coordinate systems, ensuring precise alignment for construction, design, and surveying.
Coordinate transformation – It is the mathematical process of shifting or converting the coordinates of a point, vector, or physical system from one reference frame to another. This is achieved through operations like translation, rotation, scaling, or projection to simplify analysis or integrate multi-source data.
Coordination – It is the process of organizing different disciplines, systems, and teams so they work together without conflicts.
Coordination compound – It is a compound with a central atom or ion bound to a group of ions or molecules surrounding it. It is also known as coordination complex.
Coordination mechanism – It is a structured protocol, rule, or system that manages interactions and dependencies between different technical sub-systems, software modules, or project teams. It ensures that individual components align smoothly to achieve a unified, reliable output without conflict.
Coordination number – In coordination compounds, it is the number of atoms bonded to a central atom or ion. In a space lattice, it is the number of nearest neighbours of a specific atom or ion.
Coordination policy – It is a formal set of rules, protocols, and guidelines which govern how different teams, software components, or physical disciplines (such as civil, mechanical, and electrical) interact, share data, and resolve conflicts to ensure a unified, safe, and deadlock-free system delivery.
Coordination polymerization – It is a metal-mediated addition process where monomer units coordinate with a transition-metal catalyst (such as Ziegler–Natta or metallocene systems) and insert directly into a growing metal-carbon or metal-alkoxide bond, yielding high-density, stereoregular linear polymers.
Coordination signal – It is the process of synchronizing adjacent traffic lights along a street or network so vehicle groups pass through multiple green lights in a row without stopping.
Coordination structure– It refers to a general arrangement where parts are linked to work together. it is a central metal atom bound to surrounding ligands through coordinate bonds.
Cope – In casting, it is the upper or top most section of a flask, mould, or pattern.
Cope and drag mould – It refers to a two-part sand-casting flask where the cope is the top half and the drag is the bottom half.
Cope, false – False cope is a temporary, dummy upper mould section used only to shape an irregular parting line. It is discarded or broken apart after forming the true drag and is not part of the final poured mould assembly.
Coping – It is the use of available skills, resources, and opportunities to address, manage, and overcome adverse conditions, with the aim of achieving basic functioning in the short to medium term.
Coping capacity – It is the ability of people, organizations, and systems, using available skills, resources, and opportunities, to address, manage, and overcome adverse conditions.
Coping mechanism – It consists of those means by which people, organizations, or societies unassisted from the outside meet relief and recovery needs and adjust to future disaster risk.
Coping out – It means shaping the sand in the top part of a mould (the cope) so it extends downward into the bottom part (the drag) to take the impression of a pattern.
Coping range – It is the variation in adverse conditions which a system can absorb without producing significant impacts or it is the range of adverse conditions where the outcomes are beneficial or negative but tolerable. Beyond the coping range, the damages or loss are no longer tolerable and people, organizations, or societies (or systems) are said to be vulnerable.
Coping strategies – These are the short-term responses developed by the organizations to specific shocks. These are ‘next best’ efforts to make do in a difficult situation with the hope that the household can return to normal activities and their normal livelihoods strategy.
Coplanar circular orbits – These are orbits which lie within the same plane and have a circular shape, characterized by their radius and the application of tangential thrust for efficient transfer between them.
Coplanar force – It is a system of two or more forces whose lines of action lie within the exact same two-dimensional plane. Since they operate on a single flat surface, engineers simplify their analysis using 2D vector components (x and y axes) rather than full 3D space.
Copolymer – It is a long-chain molecule formed by the reaction of two or more dissimilar monomers.
Copolymeric hydrogels – These are hydrogels composed of two types of monomers, with their properties influenced by the fraction and arrangement of these monomers in the polymer chain.
Copolymer composition – It refers to the specific arrangement and proportion of different polymeric components within a copolymer, which influences its physical properties and behaviour, such as the sergeant and soldier behaviour observed in some copolymers.
Copolymer equation – It is also known as the Mayo–Lewis equation. It is a mathematical formula in polymer engineering that predicts the instantaneous ratio of two monomers incorporated into a growing copolymer chain based on their feed concentrations and relative reactivity ratios.
Copolymer molecules – These are polymers which contain two different repeating units, synthesized through the copolymerization of two distinct monomers simultaneously, hence improving the range and diversity of their properties.
Copper (Cu) – It is a chemical element having atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Copper is used as a conductor of heat and electricity. It is a constituent of different metal alloys such as brass, and bronze etc. In steels, it is an austenite former. It decreases hot working. It is used as precipitation hardening alloying element. It is beneficial to atmospheric corrosion resistance when present in amounts exceeding 0.20 %.
Copper-accelerated acetic acid salt spray testing – It is an aggressive, accelerated laboratory corrosion test used to evaluate the durability of metallic coatings, electro-plated finishes, and anodized metals.
Copper-accelerated salt-spray test – It is an accelerated corrosion test used to evaluate the durability and corrosion resistance of metallic coatings, anodized aluminum, and decorative electroplated finishes.
Copper alloy extruded products – These are continuous metal profiles created by forcing heated or unheated copper-based metal billets through a shaped die under high pressure.
Copper alloys – These are engineering materials where copper is the main element combined with other metals to improve strength, hardness, and corrosion resistance.
Copper-aluminum alloys – These alloys are metal mixtures where either copper or aluminum is the main base metal combined with the other element, creating high-strength materials. Depending on which metal forms the majority of the mixture, these alloys split into two major categories namely aluminum-copper alloys (aluminum-dominant), and copper-aluminum alloys / aluminum bronze (copper-dominant). Aluminum-copper alloys are the alloys where aluminum is the main base metal and copper (typically 4 % to 14 %) is added to boost strength and hardness. Copper-aluminum alloys are the alloys where copper is the main base metal and aluminum (typically 5 % to 14 %). These alloys can be single-phase (two-substance) alloys containing 4 % to 9 % aluminum or multi-phase (multi-component) alloys containing 8 % to 14 % aluminum along with elements like iron, nickel, or manganese.
Copper-aluminum alloys with additions – These are multi-phase (multi-component) alloys which contain 8 % to 14 % aluminum alongside important additions like iron, nickel, and manganese to form harder, heterogeneous micro-structures.
Copper bars and rods – These are solid, elongated metal profiles produced from copper or copper alloys through extrusion, rolling, or drawing processes. In engineering terms, a rod specifically denotes a solid cylindrical section, while a bar encompasses geometric cross-sections including square, rectangular (flat), hexagonal, and octagonal shapes.
Copper base alloys – These are metallic mixtures where copper is the main base metal combined with one or more additional elements, such as zinc, tin, nickel, aluminum, or silicon, to improve mechanical strength, hardness, and wear resistance. While pure copper offers unmatched electrical and thermal conductivity, it is frequently too soft for heavy-duty structural use. Alloying improves specific qualities while retaining much of the base metal’s corrosion resistance and formability.
Copper billet – It is a solid, semi-finished piece of copper or copper alloy with a round or square cross-section which serves as raw feedstock for manufacturing further metal products.
Copper brazing – It is a term improperly used to denote brazing with a copper filler metal.
Copper cable – It is an assembly of two or more insulated copper wires bundled inside a protective outer jacket or sheath to transmit electrical power or data signals.
Copper-chlorine cycle – It is a thermochemical process which involves a five-stage cycle for producing hydrogen through the chlorination reaction and generating oxygen through thermolysis. Operating at lower peak temperatures (around 530 deg C to 550 deg C) than other cycles, it recycles all chemical reagents in a closed loop. It is notable for its high efficiency.
Copper component – It is a manufactured part made from pure elemental copper or a copper-based alloy (such as brass or bronze) designed to harness specific physical, chemical, or mechanical properties.
Copper concentrate – It is an intermediate, enriched product got by crushing, grinding, and floating raw copper ore to remove waste rock and gangue. While raw ore typically contains only 1 % to 2 % copper, copper concentrate raises that metal content to roughly 20 % to 40 %, serving as the main feed material for smelting.
Copper conductor – It is a core wire or cable made of copper which transmits electrical current or signals with very low resistance.
Copper-containing stainless steel – It is frequently called Cu-stainless steel or copper-alloyed stainless steel. It refers to a specialized family of stainless steels where copper (Cu) is intentionally added as a major alloying element (typically ranging from around 1 % to 4 % by weight) rather than left as a trace residual.
Copper corrosion – It is the gradual chemical or electro-chemical breakdown of copper and its alloys (such as brass or bronze) caused by reactions with environmental elements like oxygen, moisture, sulphur, or pollutants. Unlike iron rust, which flakes away and destroys the metal, copper corrosion typically forms a protective surface layer, such as cuprous oxide or green verdigris, which shields the inner metal from further damage.
Copper counterpart – It refers to an electrical conductor, component, or wire made entirely of pure copper. It is used as the baseline standard when evaluating alternative materials, such as copper-clad aluminum (CCA), which are designed to mimic copper’s electrical properties at a lower cost and weight.
Copper deposits -These are natural concentrations of copper-bearing minerals within the earth’s crust which be mined at a profit. They form through geological processes like magmatic activity, hydrothermal fluid circulation, or weathering, and are classified into primary types such as porphyry, sulphide, and oxide deposits.
Copper disc – It is a flat, circular piece of high-purity copper prized for its exceptional electrical and thermal conductivity, malleability, and corrosion resistance. These components are widely used in scientific research, thermal testing, and industrial manufacturing.
Copper, electrolytic – Electrolytic copper is ultra-pure copper (99.9 % to 99.99 % pure) made by passing an electric current through an acid bath to strip impurities from crude metal and deposit pure copper onto a plate.
Copper electro-winning – It is an electro-chemical process used to recover dissolved copper from an acidic solution and deposit it as high-purity solid copper onto a cathode using a direct electric current.
Copper extrusion – It is a metal-forming process where a heated copper billet is forced through a shaped steel die using high mechanical or hydraulic pressure to create long, continuous profiles with a fixed cross-sectional area.
Copper extrusion process – It is a high-temperature metal-forming process where a heated copper billet is forced through a shaped steel die using a powerful hydraulic press to create continuous, uniform cross-sectional profiles.
Copper flash smelting – it is an advanced, autogenous (self-heating) pyro-metallurgical process where finely ground copper sulphide concentrate is blown with oxygen-enriched air into a high-temperature furnace to rapidly melt and oxidize iron and sulphur.
Copper foil – It is a very thin, flexible sheet of high-purity copper (typically 0.5 micrometers to 200 micrometers thick) prized for its superior electrical conductivity, thermal performance, and malleability. It is most widely used to etch conductive traces in printed circuit boards (PCBs), act as anode current collectors in lithium-ion batteries, and provide electro-magnetic interference (EMI) shielding.
Copper-head – It is a reddish spot in a porcelain enamel coating caused by iron pick-up during enameling, iron oxide left on poorly cleaned base metal, or burrs on iron or steel base metal which protrude through the coating and are oxidized during firing.
Copper-infiltrated high-speed steel – It is a powder metallurgy composite material made by filling the open pore network of a sintered high-speed steel (HSS) skeleton with molten copper or a copper-based alloy using capillary action.
Copper-infiltrated iron and steel powder metal materials – These are composite components created by filling the internal pores of a sintered ferrous skeleton with molten copper or a copper-based alloy.
Copper-infiltrated steel – It is a composite material made through powder metallurgy by filling the internal pore network of a porous sintered iron or steel skeleton with molten copper or a copper-based alloy.
Copper infiltration – It is a process where molten copper or a copper-based alloy fills the open pores of a porous metal skeleton, such as sintered iron or steel, using capillary action.
Copper losses – There is some loss of energy in a transformer because of the resistance of the primary winding to the magnetizing current, even when no load is connected to the transformer. This loss appears as heat generated in the winding and is also to be removed by the cooling system. When a load is connected to a transformer and electrical currents exist in both primary winding and secondary winding, further losses of electrical energy occur. These losses which are because of the resistance of the windings, are called copper losses or the ‘I2R’ losses.
Copper matte – It is the mixture of copper and iron sulphides which is the feedstock to the converting process which turns chalcopyrite ore into blister copper.
Copper mine – It is an industrial site which extracts and processes copper-bearing ores (such as sulphides or oxides) from the earth to yield high-purity metal (99.99 % pure copper cathodes) through mechanical, chemical, and thermal operations.
Copper mineral – It refers to a naturally occurring inorganic solid compound or native element (such as chalcopyrite, bornite, malachite, or native copper) from which metallic copper is commercially extracted and valued for its high electrical conductivity, thermal performance, and corrosion resistance.
Copper mould – It is also called copper crystallizer. It is a water-cooled, high-purity copper or copper alloy component used in continuous casting machines to rapidly extract heat from molten metal. It solidifies the outer shell of the metal while keeping the core liquid, forming continuous billets, blooms, or slabs.
Copper naphthenate – It is a dark-green, oil-soluble organometallic compound (copper carboxylate salt) formed by reacting petroleum-derived naphthenic acids with copper compounds. It is widely used as a durable wood, textile, and cordage preservative to resist decay fungi, mould, and insect / termite attacks.
Copper-nickel – It is a single-phase binary alloy composed mainly of copper as the base metal and nickel as the principal alloying element. Since copper and nickel are neighboring transition metals on the periodic table, they show complete solid solubility. This means they blend seamlessly in any proportion at an atomic level without forming secondary phases, creating a face-centered cubic (fcc) crystal structure.
Copper-nickel alloys – These are alloys of copper and nickel, with nickel content ranging between 10 % to 45 % with normally small quantities of iron and manganese. These alloys have outstanding resistance to sea-water corrosion.
Copper-nickel-zinc alloys – These alloys are widely known as nickel silver. These are metal compositions made of copper, nickel, and zinc which feature a bright, silver-like appearance despite containing zero actual silver.
Copper orientation – It mainly refers to crystallographic grain texture in materials science, manufacturing grain alignment in mechanical and hardware engineering, or layer alignment in electrical PCB (printed circuit board) manufacturing.
Copper oxide – It is an inorganic transition metal compound composed of copper and oxygen, mainly functioning as a p-type semi-conductor with valuable catalytic, thermal, and antimicrobial properties. It exists mainly as cupric oxide (CuO) or black solid and cuprous oxide (Cu}2O) or red solid).
Copper oxide nano-particles – These are ultrafine particles sized between 1 nano-meter and 100 nano-meters made of copper and oxygen. These particles function as p-type semi-conductors with a narrow band gap (about 1.2 electron-volts to 1.4 electron-volts), high thermal conductivity, and a large surface-to-volume ratio that boost catalytic and electrical performance.
Copper phase – It is frequently designated as the alpha phase). It refers to a distinct, uniform structural state where copper acts as a host lattice or a primary solid solution, such as face-centered cubic (fcc) copper alloyed with elements like nickel, zinc, or tin.
Copper pipe – It is a type of piping made from copper, characterized by its resistance to corrosion, good strength, low electrical resistivity, and high thermal conductivity, making it suitable for applications such as water pipes and heat transfer systems.
Copper plate – It is a flat, solid sheet or piece of copper or copper alloy shaped by rolling, extrusion, or casting. Valued for high electrical and thermal conductivity, corrosion resistance, and malleability, it is widely used in electrical distribution, thermal management, and grounding systems.
Copper plate sensor – It is a specialized measurement device which uses a copper disk or plate to capture physical data, very frequently thermal heat flux or surface temperature. The high thermal and electrical conductivity of copper allows the sensor to rapidly and accurately track changes in its environment.
Copper plating – It is a process where a thin layer of copper is deposited on the surface of another material, frequently another metal or even a non-metal. This process is used for several reasons, including improving electrical conductivity, corrosion resistance, providing a decorative finish, and improving solderability.
Copper products – These products refer to different manufactured items made from copper, including over 250 types of copper alloys and nearly a thousand different products, mainly used in several industries such as electric power, construction, transportation, and machinery.
Copper profiles – These are extruded, drawn, or rolled metal sections of copper or copper alloys featuring custom or standard non-geometrical cross-sections.
Copper refining – It is the final purification stage of metallurgical processing which removes remaining trace impurities from smelted or leached copper, elevating its purity to 99.99 %. This high purity is necessary to ensure maximum electrical and thermal conductivity.
Copper sections – These are custom-shaped, extruded, drawn, or cast copper profiles designed with specific geometric cross-sections for structural, mechanical, and high-conductivity electrical applications. Standard sections are rectangular bars, squares, L-angles, U-channels, T-profiles, and hollows.
Copper seed – It is a thin layer of copper deposited over a wafer, used in processes such as FOWLP (fan-out wafer-level packaging) for masked electro-chemical deposition, which can also serve as a patterned shield electrode when an additional lithography step is applied.
Copper seed layer – It is a thin film of copper deposited over a substrate (such as a silicon wafer) to conduct electrical current during electro-plating or electro-chemical deposition. It serves as a necessary base layer so that bulk copper can uniformly electro-plate onto microelectronic features like trenches and vias.
Copper sensor – It is a widely used device for evaluating thermal protective clothing, featuring a copper disk surrounded by a thin copper ring to minimize heat loss, and utilizing thermocouples to measure the average temperature, allowing for accurate measurement of heat flux during exposure. It normally refers to one of three devices namely a thermal heat-flux sensor with a copper disk, an inductive proximity coil which detects metal, and an electro-chemical sensor using copper electrodes to detect specific ions or chemicals.
Copper slag – It is a glassy, rock-like waste material left over from the high-temperature smelting and refining of copper ore. It consists mostly of iron oxides and silicon di-oxide (silica), with small quantities of aluminum, calcium, and trace metals. It consists of hard, dark brown or black, angular, glass-like granules. Coppe slag is heavy, durable, and scores high on the Mohs hardness scale.
Copper smelting – It is a pyro-metallurgical extraction process where copper concentrate is heated in a furnace with a flux (such as silica) to melt the material, separate iron and sulphur impurities, and produce an intermediate molten sulphide mixture called copper matte.
Copper stave cooler – It is a cooling plate system, typically made of copper, used in blast furnaces and other high-temperature industrial processes to cool the furnace’s lining and protect its shell. The staves, normally water-cooled, are strategically placed on the inner surface of the furnace to remove excess heat and prevent overheating and damage to the refractory lining and outer shell.
Copper steels – These are carbon or low-alloy steels which contain a small, deliberate addition of copper (typically 0.2 % to 0.5 %) to improve considerably atmospheric corrosion resistance.
Copper strip corrosion – It is a qualitative test which is widely standardized as the copper strip test. It used to evaluate the corrosiveness of petroleum products, lubricants, and liquid fuels on copper and copper alloys.
Copper strip test – It is a quality control method used to measure the corrosiveness of petroleum products and lubricants by submerging a polished copper coupon into a fluid sample and visually comparing its discoloration against a standard rating scale.
Copper substrate – It is a foundational material which bonds high-purity copper to an insulating or metal base. It delivers exceptional thermal and electrical conductivity, making it vital for high-power circuits and effective heat management.
Copper sulphide ore i= It s a natural mineral deposit where copper is chemically bonded with sulphur (CuxSy), typically found deep underground in reducing, low-oxygen environments. It serves as the main global source of metallic copper, processed mainly via crushing, froth flotation, smelting, and electro-refining.
Copper tailings – These are the finely ground waste rock and mineral slurry left over after valuable copper minerals are extracted from mined ore during beneficiation.
Copper-tin alloys – These are normally known as tin bronzes. These are metallic mixtures composed primarily of copper with tin as the major alloying element (typically ranging from 4 % to 25 %).
Copper tube – It is a precise cylindrical conduit made from high-purity copper or copper alloys used to transport fluids or transfer heat.
Copper tubing – It is a seamless, non-ferrous hollow metal conduit manufactured to transport fluids or gases or act as a heat-transfer medium in mechanical, thermal, and fluid systems.
Copper wire – It is a single or stranded electrical conductor made from copper, designed to carry electrical current or signals with high efficiency and minimal resistance.
Copper-zinc alloys – These alloys are known as brass. These alloys are substitutional solid solution metallic materials where zinc atoms replace copper atoms in a face-centered cubic crystal lattice.
Copper-zinc equilibrium – It refers to the stable phase states and solubility limits of copper-zinc alloys (brasses) at different temperatures and compositions, as mapped out by the binary phase diagram.
Coprecipitation – It is a process where two or more dissolved ions or compounds precipitate simultaneously from a solution to form a uniform, solid precursor or mixture.
Co-prime integers – Two integers ‘m’ and ‘n’ are coprime, relatively prime or mutually prime, if the only positive integer that is a divisor of both of them is 1. Hence, any prime number which divides ‘m’ does not divide ‘n’, and vice versa. This is equivalent to their greatest common divisor (GCD) being 1. One says also ‘m’ is prime to ‘n’ or ‘m’ a is coprime with ‘n’. The numbers 8 and 9 are coprime, despite the fact that neither, considered individually, is a prime number, since 1 is their only common divisor. On the other hand, 6 and 9 are not coprime, since they are both divisible by 3. The numerator and denominator of a reduced portion are coprime, by definition.
Co-prime numbers – These are two or more integers which share no common positive integer factors other than 1.
Co-processing – It is the simultaneous use of non-recyclable waste and alternative materials as a substitute for fossil fuels (energy recovery) and natural mineral resources (material recycling) within existing industrial manufacturing processes.
Coprocessor – It is a specialized hardware component or supplementary processor designed to offload specific, compute-heavy tasks from the main central processing unit (CPU) to boost overall system speed and efficiency.
Copy milling – It is also known as tracer milling or duplicate milling. It is a machining process where a cutting tool duplicates the shape of a physical master template or model onto a work-piece.
Coral aggregate concrete – It is a specialized construction material made by mixing cement, water (freshwater or seawater), and porous natural coral debris or coral sand as an aggregate.
Corbel – It is an arrangement of brick in which each course projects beyond the adjacent course.
Cord – It is several strands of yarn twisted together.
Cordierite – – It a ring silicate mineral with the composition (Mg,Fe)2[Si5Al4O18]·nH2O, characterized by low refractive indices and birefringence, normally found in metamorphic environments and occasionally in contaminated igneous rocks. It is also specifically synthetic magnesium aluminosilicate. It is a high-performance technical ceramic categorized by its chemical formula, 2MgO ⋅ 2Al2O3 ⋅ 5SiO2. It is widely engineered for industrial applications because of its ultra-low coefficient of thermal expansion (CTE) and exceptional thermal shock resistance. While natural cordierite exists as a cyclosilicate mineral (known as iolite in gemology), engineering applications almost exclusively utilize synthesized versions to guarantee chemical purity, consistency, and structural stability.
Cord fabric – It is a fabric with plied or cabled yarns in the warp direction and a light weight filling yarn spaced only sufficiently to process the fabric.
Cord stripper – It is a tool for easy separation of steel cords from the belt as part of the splicing procedure.
Cordwood construction – It is a natural building method. The design consists of short, debarked logs (log-ends normally cut to lengths of 200 millimeters to 600 millimeters are laid transversely, meaning they are piled crosswise across the width of the wall rather than lengthwise. The logs are bound together using a specialized matrix, typically consisting of mortar beads on the inner and outer edges, with an insulating infill (like sawdust and lime) packed in the central core cavity.
Cordwood loading – It refers to the mechanical behaviour, stress distribution, and capacity of a cordwood masonry matrix under structural forces. Since cordwood walls are a composite system made of short, crosswise log-ends embedded in a mortar matrix, engineering analysis looks at how loads are transferred through these materials.
Cord yarn – It is also called cabled yarn. It is a heavy-duty, high-strength linear structure made by twisting two or more ply yarns (or folded yarns) together.
Core -It is a specially formed material inserted in a mould to shape the interior or other part of a casting Which cannot be shaped as easily by the pattern. In a ferrous alloy prepared for case hardening, it is that portion of the alloy which is not part of the case. Typically considered to be the portion that (i) appears dark (with certain etchants) on an etched cross section, (ii) has an essentially unaltered chemical composition, or (iii) has a hardness, after hardening, less than a specified value. In a nuclear plant, core is the central heat-producing part of a nuclear reactor which contains the fuel assemblies. In case of wire rope, the core of a wire rope is the foundation of a wire rope. It runs through the centre of the rope. Its primary function is to support the wire strands in the rope and to maintain them in their correct relative positions during the operating life of the wire rope. The core supports the strands and helps to maintain their relative position under loading and bending stresses. Core in mining operation is the long cylindrical piece of rock, around 25 millimeters in diameter, brought to surface by diamond drilling.
Core analysis – It is the laboratory-based examination and direct measurement of physical, petro-physical, and fluid-flow properties using cylindrical rock samples (cores) retrieved from sub-surface formations during drilling. It serves as a main method in petroleum and reservoir engineering to calibrate well logs, evaluate formation productivity, and design recovery strategies.
Core-annular flow – It is a technique used to transport heavy, high-viscosity crude oils by surrounding the oil core with a thin lubricating water annulus along the pipe wall to drastically reduce pumping friction and pressure.
Core arbor – It is a stiff iron frame or skeletal structure placed inside a large sand core. It adds strength, prevents the heavy sand core from breaking, and makes it easier to lift and position the core inside the mould.
Core assembly – In casting, it is a complex core consisting of a number of sections.
Core assembly moulding – It is the moulding process in which the core box is used instead of the pattern and the produced sand cores are assembled directly into the mould. It is mainly used for batch production of complex castings or repeated production of large castings.
Core attributes – These attributes define the fundamental technical competencies, problem-solving habits, and professional traits needed to design, build, and maintain safe and effective solutions.
Core axis – It refers to the central vertical line around which the reactor core is structured, serving as a reference point for the arrangement of components such as the neutron in-core instrumentation and control rods within the nuclear reactor.
Core-baking dielectric – It refers to a high-speed heating method using high-frequency alternating current between parallel electrodes to uniformly dry and cure sand-binder core structures from the inside out in seconds or minutes.
Core balance current transformer – It is also called a zero-sequence current transformer. It is a ring-shaped device used to detect earth faults and leakage currents in electrical systems.
Core barrel – It is a specialized cylindrical tool attached to a drill string used to cut, capture, and retrieve intact, cylindrical samples (cores) of rock, soil, concrete, or sediment from the subsurface. It is that part of a string of tools in a diamond drill hole in which the core sample is collected.
Core baseline – It is a formally approved, frozen reference point, such as a specification, design configuration, or project plan, used as the standard for measuring future performance and controlling changes.
Core binder – In casting, it is a material used to hold the grains of core sand together.
Core blister – It is a surface casting defect which appears as a shallow, smooth-walled cavity or bubble covered by a thin film of liquid metal.
Core blow – It is a gas pocket in a casting adjacent to a cored cavity and caused by entrapped gases from the core.
Core blower – It is a machine for making foundry cores using compressed air to blow and pack the sand into the core box.
Core blowing machine – It is also called core shooter. It is an industrial device used in metal casting foundries to inject a sand-and-binder mixture into a hollow mould tool called a core box using compressed air. It rapidly packs and hardens the sand to form complex internal cavities for metal parts.
Core body dimensions – These dimensions are the exact measurements of the main body of the core which comes into contact with the molten metal. These dimensions determine the precise size, shape, volume, and surface area of the internal cavity or hole in the finished casting.
Core box – It is the mould for sand core making, whose inner cavity has the shape and size needed for the sand core. It is normally made of metal, wood or plastic. It can be divided into integral type and bi-section type as per its structure and can be divided into hot core box and cold core box as per its use temperature.
Core breaker – It is a machine for crushing cores or for removing cores from the castings.
Core cavity – It is the interior form of a core box which gives shape to the core. It is also the cavity produced in a casting by use of a core.
Core circuit – It typically refers to either a foundational functional domain within a telecommunications core network or the primary processing and control infrastructure of an electronic system.
Core clearance – It is also called core allowance. It is the intentional gap or dimensional tolerance built between the core print and the mould seat. Adequate clearance ensures the core can be easily placed into the mould without crushing the sand, while remaining tight enough to prevent molten metal from leaking into the print area (called core flash).
Core collapsibility – It is the ability of a core to break down, disintegrate, or lose its structural strength easily after the poured metal cools and solidifies. This property allows the solidified casting to contract freely without cracking and ensures the core material can be easily cleaned out from narrow internal cavities.
Core competencies – It is the deep proficiency in the organization which enables it to deliver unique values to the customers. It embodies organization’s collective learning especially coordination of the diverse production skills and the integration of the multiple technologies. ‘Core competencies’ is hard for competitors to copy or to procure. Core competencies create sustainable competitive advantage for the organization and helps it to branch into a wide variety of related markets. It contributes substantially to the benefits of the organization’s products offer to the customers and hence effectively helps in the businesses of the organization.
Core components – These refer to the foundational, indispensable parts, functions, or building blocks which make up a system, product, or process and drive its main performance and success.
Core compound – It is a commercial chemical mixture or bonding agent added to refractory sand to provide the mechanical strength, hardness, and stability needed to form internal cavities and hollow sections inside a mould.
Core cooling – It refers to the process or system designed to remove thermal energy from the central part (the core) of a device, structure, or equipment to prevent overheating, structural failure, or degradation.
Core crab – It is an iron framework or skeleton embedded inside a large sand core to add structural strength and make it easier to handle safely.
Core crack – It is a fracture or breakage in a sand or refractory insert used inside a metal-casting mould. This defect allows molten metal to seep into unwanted spaces, causing dimensional errors, rough surfaces, or structural failure in the final metal product.
Core cracking – It normally refers to internal fractures, structural separation, or failures occurring within the central or innermost portion (the core) of a material, component, or system.
Core crush – It is a collapse, distortion, or compression of the core.
Cored bars – In powder metallurgy, these are compact of bar shapes heated by their own electrical resistance to a temperature high enough to melt its interior.
Cored coil – It is an electrical winding or inductor which includes a central core made of a magnetic or ferromagnetic material, such as iron, steel, or ferrite, rather than relying on air.
Core deformation – It refers to the change in shape, volume, or structural integrity of an inner material, component, or system assembly (the core) when subjected to external mechanical loads, thermal stress, or fluid pressures.
Core density – It is the weight of the sand and binder mix divided by its total volume (mass per unit volume). It measures how tightly packed the sand grains are inside a mould core.
Cored forging – It is a specialized hot-forming manufacturing process which uses custom-shaped dies equipped with movable core pins to create internal cavities, holes, or complex inner ports in a single pressing stroke.
Core diameter – It is the cross-sectional diameter of the core of an instrument, which influences its strength and flexibility. A larger core diameter results in a more robust and rigid instrument. For threads and fasteners, the core diameter (also called the minor diameter) is the smallest diameter of a screw thread, measured across the root of an external thread or the crest of an internal thread. In case of optical fibres, the core diameter is the physical width of the central glass or plastic region which guides light, which has a higher refractive index than the surrounding cladding. In drilling and geo-technical engineering, the core diameter is the cross-sectional size of the cylindrical rock, soil, or concrete sample retained inside a core barrel or extracted through a coring bit. In electrical and transformer engineering, the core diameter refers to the cross-sectional width or effective iron area of the magnetic core (such as in transformers or inductors) which carries magnetic flux.
Core dimensions – It refer to the precise physical measurements of a core, a removable insert (normally made of sand, metal, or ceramic) placed inside a mould cavity to create internal geometries, hollow spaces, recesses, or undercuts. The dimensions of the core directly define the internal dimensions, wall thicknesses, and functional passages of the final cast component.
Cored inductor – It is a passive electrical component made of a conductive wire coil wrapped around a central material (the core) which stores energy in a magnetic field and opposes sudden changes in electrical current.
Core disruptive accident – It is an extreme, very low-probability severe accident in nuclear engineering where fuel melting and core geometry changes lead to a rapid, super-prompt-critical reactivity excursion and the violent mechanical disassembly of the reactor core.
Cored motor – It is a traditional electric motor where the copper wire windings are wrapped directly around a solid or laminated iron structure. This iron skeleton serves as a highly efficient magnetic pathway to focus electromagnetic flux.
Cored mould – It is a mould incorporating passages for electrical heating elements, steam, or water.
Cored reactor – It is a type of reactor which incorporates a magnetic core to improve inductive reactance, typically used in reactive compensation schemes and to balance impedance in electrical systems. It can be designed with an air gap in series with steel components to achieve higher values of reactance.
Core drilling – It is the process of getting cylindrical rock samples by means of annular-shaped rock-cutting bits rotated by a borehole-drilling machine.
Core dryers – It is also spelled as core driers. Core dryers are specialized support trays or shape-matching forms used to hold and maintain the precise contour of an unbaked sand core while it goes through a core oven to cure or bake. These are constructed from metal or sand for conventional baking or from plastic material for use with dielectric core-baking equipment.
Cored seamless process – It is also known as the flash-less casting or flash-less moulding process. It is an advanced manufacturing method used to produce hollow, complex-shaped components without generating a parting line seam or excess material flash.
Cored solder – It is a solder wire or bar containing flux as a core.
Cored wire – It is a tubular metallic sheath (typically steel) filled with powdered or granulated materials. such as flux, metal powders, alloying elements, deoxidizers, or modifiers.
Core electrons – These electrons are the inner-shell electrons of an atom which are not involved in chemical bonding. They occupy the filled inner energy levels (shells) closest to the atomic nucleus. They do not participate in forming chemical bonds or reacting with other atoms.
Core extruder – It is a specialized screw-feed machine which continuously pushes prepared core sand through a shaped die to produce uniform sand cores, normally with a simple cylindrical cross-section.
Core fibre – It is the central, innermost region of an optical fibre or a core-shell composite fibre. It is the central cylindrical strand of ultra-pure glass (silica) or plastic through which light signals propagate. It guides light over long distances.
Core filler – It is the material, such as coke, cinder, and saw-dust which is used in place of sand in the interiors of large cores. It is normally added to aid collapsibility.
Core fin – It is a casting defect, a depression in the casting caused by a fin on the core which was not removed before the core has been set, or by paste which has oozed out from between the joints.
Core flash – It also known as a casting fin or burr. It refers to a thin, unwanted sheet or ridge of excess metal that forms when molten metal leaks into unintended gaps or cracks within or surrounding a core assembly.
Core float – It is a casting defect where a sand core shifts or rises upward toward the cope (top) surface of the mould. This happens since the buoyancy force of the dense liquid metal pushes up against the lighter sand core.
Core flow – In bulk material handling, core flow happens when bulk powder or granular material flows toward an outlet through a narrow channel formed directly within the powder itself, leaving stagnant regions of material along the lower walls of the hopper until it is nearly empty. In fluid dynamics and fluidized systems, core flow describes the central portion of a fluid stream or pipe flow (such as an annular flow) where the main velocity and momentum are concentrated, distinct from the near-wall boundary layers or liquid films. In manufacturing and sub-surface machining, CoreFlow is a patented TWI (The Welding Institute) solid-state machining process which integrates sub-surface networks of channels into monolithic 2D or 3D metal parts for thermal management and heat exchangers.
Core fluid – In oil and gas exploration, a core fluid (frequently referred to as a drill-in fluid) is a specially designed clean fluid used while drilling through the reservoir section (the ‘core’ zone) of a well. in microfluidics and flow-focusing devices, the core fluid is the inner stream of fluid which forms at the nozzle. In pipeline engineering, a core fluid is the central fluid (typically a highly viscous oil) wrapped in a lubricating outer layer of a different fluid (typically water).
Core for casting – It is separable part of a mould which normally is made of sand and a binder to create openings and various specially shaped cavities in castings.
Core for coiled products – It is the central cylindrical tube, rod, or magnetic center around which materials like steel sheets, paper, wire, or electrical windings are wrapped for support, storage, or electro-magnetic function.
Core for rolled products – It is a hollow cylinder on which a coiled product can be wound which forms the inside diameter of a coil. It is a rigid cylindrical tube placed at the centre of a roll to provide internal structural support and prevent the material from collapsing or deforming.
Core forging – It is displacing metal with a punch to fill a die cavity. Also, it is the product of such an operation.
Core fracture – It refers to a central internal crack or separation which develops inside a work-piece during intensive deformation processes like extrusion, drawing, or rolling. In metal casting, core fracture (also known as a core break) is a casting defect defined as the cracking, snapping, or structural failure of a sand or ceramic core while inside the mould cavity. Cores are used to create the internal hollow sections and cavities of a cast product. When a core fractures, its geometric integrity is lost, allowing molten metal to displace the broken core parts or rush into the newly formed cracks.
Core frame – It is a skeleton-like structural frame or support used instead of a solid, complete core box to shape and reinforce intermediate or large sand cores.
Core function – It is the main, necessary purpose or action which a system, product, or component is to perform to deliver its main value, focusing on what it accomplishes rather than how it is built.
Core grinder – It is a specialized machine used to shape, smooth, or grind sand cores. It trims flat faces or cuts precise tapers on cylindrical cores to ensure they fit correctly and align properly inside a metal casting mould.
Core gum – It is an adhesive or binder material, frequently sodium silicate-based, pitch, or plant-derived gums like dextrin, used to bond sand aggregate together or paste separate pieces of a mould core into a single unit.
Core hardness – It is a numerical measure of the bonding strength, density, and resistance to scratching or erosion of a baked, cured, or dried sand core used to form internal cavities in a metal casting.
Core interface – It refers to the boundary between the face skins and core of sandwich composites, where failure can occur because of the debond cracking or separation from core crushing under blast loading conditions.
Core jig – It is also called a core setting jig or gauge. It is a specialized device used to accurately position, align, and set fragile sand cores into a mould cavity before pouring metal. It ensures the core sits in the exact correct spot to prevent wall thickness errors or core shift.
Core knock-out – It is the process in which sand core is removed from the inner cavity of the casting by hammering or any other way.
Core knock-out machine – It is a mechanical device for removing cores from castings.
Core layer – It is the inner layer between two skin layers in a sandwich structure, serving as a separator which adds thickness and is typically made from materials like metal foam to reduce weight while maintaining strength.
Coreless induction furnace – It has a fairly simple construction. It basically consists of a refractory vessel and the surrounding coil borne by a steel frame. When an alternating current flows through the coil, it creates an electromagnetic field which in turn induces eddy currents in the charged material. This charge material gets heated up as per Joule’s law and with further heat the charge material melts. The main component of the coreless IF consists of a crucible, a power supply unit consisting of transformer, inverter and capacitor bank, the charging arrangement, the cooling system for the power supply and furnace coil, process control system, and the fume extraction equipment. In this furnace, the heart of the furnace is the coil, which consists of a hollow section of heavy duty, high conductivity copper tubing which is wound in the form of a helical coil. Coil shape is contained within a steel shell and magnetic shielding is used to prevent heating of the supporting shell. To protect it from overheating, the coil is water-cooled, the water being recirculated after cooling in a cooling tower. The shell is supported on trunnions on which the furnace tilts to facilitate pouring. The crucible is formed by ramming a granular refractory between the coil and a hollow internal former which is melted away with the first heat leaving a sintered lining.
Core lightener – It is a shape or size of core material used to reduce weight in pattern castings and match plates.
Core losses – Since magnetic lines of force in a transformer are constantly changing in value and direction, heat is developed because of the hysteresis of the magnetic material (friction of the molecules). This heat is to be removed. Hence, it represents an energy loss of the transformer. High temperatures in a transformer drastically shortens the life of insulating materials used in the windings and structures. For every 8 deg C temperature rise, life of the transformer is cut by one-half, hence, maintenance of cooling systems is critical. Losses of energy, which appears as heat because of both the hysteresis and the eddy currents in the magnetic path, is known as core losses. Since these losses are because of the alternating magnetic fields, they occur in a transformer whenever the primary is energized, even though no load is on the secondary winding.
Core machine – It is automated equipment used to compress or inject a sand-and-binder mixture into a tool called a core box. It rapidly hardens this mixture using heat or gas to form precise, disposable interior shapes. These solid sand inserts are then placed inside moulds to create hollow cavities, undercuts, or complex passages in metal castings.
Core maker – Core maker is a skilled worker or machine operator who builds shaped forms, called cores, out of sand, resin, or refractory materials. Placed inside a casting mould, these cores form hollow sections, internal holes, or complex passages in the final metal product which the outer mould cannot shape on its own.
Core-making – It is the process in sand casting process which uses core sand, core box and other toolings to make sand core, including hand core-making and machine core-making.
Core-making line – It is the equipment used to make ready-to-use single cores and / or core assemblies. A line can consist of, e.g., a sand preparation equipment, core making machine, equipment for handling, deflashing, assembling, coating and drying of cores.
Core-making machine – It is specialized industrial equipment used to compress and harden a mixture of sand and a chemical binder inside a mould (core box) to produce solid, precise sand shapes. These shapes, called cores, are placed inside larger casting moulds to form hollow internal cavities, passages, or undercuts in metal parts.
Core-making machinery – It consists of machines used to make solid and / or hollow cores.
Core-making mixture – It is a mixture of raw sand, different binders and additives mixed in a certain proportion, which meets a certain property requirement of making sand core.
Core material – It refers to the central, internal, or supporting structural layer of a component, composite, or manufacturing process. In composite sandwich structures, it is a light-weight, high-strength layer placed between two stiff outer face sheets (such as metal sheets or fibre-reinforced laminates). In metal casting, it is a pre-shaped insert, typically made of bonded sand, ceramic, or metal, placed inside a mould cavity prior to pouring molten metal. In thermal and vacuum insulation, It is the internal bulk or ‘backbone’ material inside vacuum insulation panels which limits gas molecule movement.
Core mechanism – It is the main, essential process, rule, or system which drives how a concept, machine, game, or cognitive function operates.
Core melt – It is the overheating of the core of a nuclear reactor which results in the core melting.
Core melt accident – It is an event or sequence of events where a nuclear reactor core overheats to the point that at least part of the nuclear fuel melts. It is a severe nuclear reactor accident in which heat generated by radioactive decay exceeds the heat removed by cooling systems, causing fuel elements or the fuel matrix to exceed their melting points.
Core melt-down – It is a severe nuclear accident which happens when the heat generated in a nuclear reactor core exceeds the quantity removed by its cooling systems.
Core micro-structure -It refers to the microscopic structure, arrangement, and spatial distribution of the internal phases, grains, or defects within the central, innermost region of a material. This internal layout directly dictates how the material behaves under stress, temperature, or chemical exposure, distinguishing it from the surface micro-structure or skin which interacts directly with the outside environment.
Core mode – It very frequently refers to the main or fundamental optical path (or light-guiding state) where electro-magnetic waves or light travel through the central core of an optical fibre core rather than leaking into the surrounding cladding.
Core model – It refers to a high-level, simplified representation or architecture which captures the essential data, functional components, or user journeys of a system.
Core mud – It is a thick, paste-like daubing mixture used to repair, patch, or correct surface defects, cracks, or minor breakages in sand cores before they are placed into a mould for metal casting.
Core network – It is the central, high-capacity backbone of a telecommunication or computer system which routes data, connects smaller sub-networks, and manages user services.
Core network entities – These refer to the modular network functions within the 5G core network architecture which enable service-centricity, flexibility, and programmability, allowing for the decoupling of control and user planes, support for different radio access technologies, and management of both IP (internet protocol) and non-IP data payloads. These entities facilitate dynamic interconnection of user flows with network slices based on service requirements.
Core oil – It is a binder for core sand which sets when baked and is destroyed by the heat from the cooling casting.
Core oven – It is a specialized industrial heating unit used to bake, cure, or dry sand cores, the shaped sand inserts which form internal cavities or complex hollow features in metal castings. Baking activates chemical binders or removes moisture, giving the sand core structural strength to withstand molten metal.
Core paste – It is a specialized, high-temperature adhesive used to bond separate sand core pieces or repair broken sections of moulds and cores before casting metal. It ensures complex internal pathways stay locked in position and prevents molten metal from leaking into joints.
Core permeability – It is the measure of a porous medium’s ability to transmit fluids, determined through laboratory testing of core samples under steady-state flow conditions with a single-phase fluid. It is influenced by factors such as core integrity and handling, as well as environmental conditions.
Core pins – These are precision metal rods placed inside a mould to form internal holes, voids, slots, or complex geometries in plastic parts or metal castings.
Core plates – These are heat-resistant plates used to support cores during baking. They can be metallic or non-metallic, the latter being a requisite for dielectric core baking.
Core plug – It is a thin metal disc or cup (frequently made of mild steel, brass, or stainless steel) pressed into machined holes in an engine block or cylinder head.
Core porosity – It is the porosity of a rock sample measured directly in a laboratory from physical core samples got during drilling. It is calculated as the ratio of pore (void) volume to the total bulk volume of the core sample.
Core print – It is the projections attached to a pattern in order to form recesses in the mould at points where cores are to be supported.
Core print dimensions – These are the measurements of the extended portions of the core (the prints) which sit in recessed seats within the mould. These extensions do not touch the molten metal. Instead, they support, align, and lock the core into place to prevent shifting or floating during pouring.
Core process – A process that follows an established order and is central to the performance of the process system of which it is part.
Core purpose – It is the fundamental, enduring reason an organization exists beyond just making money. It is the systematic application of science, mathematics, and creative problem-solving to transform theoretical ideas into safe, efficient, reliable, and sustainable real-world solutions which benefit society.
Core radius – It is the radius of the central solid cylinder of a tool (like an end-mill or drill bit) from which the cutting flutes extend. It determines the core strength, rigidity, and chip clearance space of the tool. It is also the characteristic radius of the inner core region of a vortex (such as a blade tip vortex), inside of which the flow behaves like a forced (solid-body) rotation before transitioning to a free vortex.
Core, ram up – A ram up core is a specialized preformed sand or ceramic core placed directly against or into a recess on a pattern before the moulding sand is packed around it. When the moulding sand is rammed, the core is locked securely into the main sand mould.
Core recovery – It is the proportion of a drilled rock or soil sample successfully retrieved from the ground during a drilling operation, expressed as a percentage of the total distance drilled. It is the ratio of the length of the core sample retrieved to the total length of the core run (the depth penetrated by the drill).
Core refractoriness – It is also called core refractiveness. It is the ability of a mould core to resist extreme heat from molten metal without melting, softening, fusing, or breaking down. This property prevents the core from deforming or fusing into the casting, ensuring accurate internal shapes and clean surfaces.
Core region – It is the specific area within the cross-section of a structural member (such as a column or pier) where an axial load can be applied without generating any tensile stress anywhere in the cross-section.
Core rod – It a steel wire or metal bar embedded inside a sand core to reinforce, stiffen, and provide mechanical strength against the weight and pressure of flowing molten metal. In powder metallurgy, it is a member of a die assembly used in moulding a hole in a compact.
Core room – It is the dedicated department or work-space where expendable interior shapes, called cores, are manufactured. These sand and binder bodies are placed inside moulds to shape complex internal cavities, hollow sections, or deep undercuts in metal castings.
Core rotation – It refers to the angular motion and spinning dynamics of a planet’s liquid or solid core relative to its mantle, shaped by factors like viscosity, electro-magnetic coupling, and thermo-chemical convection.
Core rubber – It is also so called ‘insulation gum’. It is the rubber used for filling the gaps in a steel cord and improving adhesion between the cord and the top and bottom covers.
Core sag – It is a casting defect or condition where a sand core deforms, dropping in height and spreading in width under its own weight before the binder hardens or during handling. Core sag happens as a result of insufficient green strength of the sand to support its own weight. It leads to a distorted internal cavity or incorrect metal thickness in the final casting.
Core sample – A cylinder sample normally 25 millimeters to 125 millimeters in diameter drilled out of an area to determine the geologic and chemical analysis of the overburden and the mineral deposit.
Core sand – In casting, it is the sand used for making cores to which a binding material has been added to get good cohesion and permeability after drying. Normally sand low in clays is used.
Core sand mixer – It is an industrial machine used to blend base sand (like silica or quartz) uniformly with chemical binders, resins, catalysts, and additives. This thorough mix creates strong, precise sand cores used to form hollow cavities or complex internal features in metal castings.
Core saturation – It is the state in which a ferro-magnetic core (such as in a transformer or inductor) reaches its maximum magnetic flux density, meaning further increases in the magnetizing force produce little to no increase in magnetic flux.
Core separation – It is a partial or complete breaking of the core node bond.
Core setter – Core setter is a worker or an automated machine that places preformed sand or metal cores precisely into a mould cavity before pouring metal. This ensures internal hollows, holes, or complex shapes form correctly inside the final casting.
Core setting jig – It is a specialized guiding or positioning device used to place a sand core accurately and repeatably into a mold cavity. It ensures proper alignment, prevents core shift, and maintains exact wall thicknesses in the final metal casting.
Core shell – It refers to a structure composed of an inner 3D nano-material wrapped in an outer material, which improves properties such as stability, light absorption, and charge separation, hence facilitating applications in fields like catalysis, and materials chemistry.
Core-shell heterostructure – It is a composite material made of an inner core material completely or partially enclosed by an outer shell of a different material.
Core shift – It is a variation from the specified dimensions of a cored casting section because of a change in position of the core or misalignment of cores in assembly.
Core shooter – It is an automated machine used to inject a mixture of sand and binder resin into a core box under pneumatic pressure. This process rapidly forms solid sand cores which are placed inside metal moulds to create complex hollow spaces and internal cavities in final metal castings.
CoreSight debug architecture – It refers to a flexible debug solution for ARM (advanced RISC machine) Cortex processors that separates the debug interface from the main processor logic, allowing for multiple processors to share a debug interface block and facilitating a scalable debug system. This architecture improves consistency across the Cortex-M processor family and simplifies support for development tools.
Core size – It refers to the cross-sectional dimensions, diameter, or thickness of the central part of an object, structure, tool, or electrical component.
Core specification – It is the foundational set of essential requirements, rules, and functional limits which define the primary behaviour, architecture, and interfaces of a system, product, or technology.
Core spindle – It is a central rotating shaft or arbour used to support and rotate a core barrel when workers build up and shape large cylindrical sand cores.
Core splicing – It is the joining of segments of a core by bonding, or by overlapping each segment and then driving them together.
Core sprayer – It is a mechanical device or sprayer apparatus used to apply liquid coatings, washes, or parting agents onto a preformed sand core to improve its surface finish and heat resistance.
Core stickle template – It is also called core stickle sweep. It is a specialized device made of wood or metal used in metal casting foundries to shape and scrape away extra sand to form precise contours for specific types of moulds or large cores.
Core store-house and conveying system – It is a system used for automatic conveying, storing and distributing of sand core, e.g., core three-dimensional store-house.
Core, strainer – It is also called strainer tub. Strainer core is a perforated refractory or mica plate placed in the gating system. It traps slag, dross, and solid impurities while controlling the flow rate of molten metal entering the mould cavity.
Core switch – It is a high-capacity ‘layer 3’ network device which acts as the backbone or central hub of a hierarchical organization, campus, or data centre network. Core switches are high-capacity switches located at the top of a cloud data centre network, connecting aggregation switches and providing interfaces to wide area networks (WANs). They are characterized by high-band-width capabilities, modular designs, and features like network security and monitoring to ensure reliability.
Core technology – It refers to the fundamental building blocks, scientific principles, or important applied methodologies which underpin all technological systems and enable the creation of complex products and infrastructure.
Core temperature – It refers to the temperature measured at the deepest point or central region of a component, system, or assembly, as distinct from the surface or skin temperature.
Core thickness – It refers to the measured thickness of the innermost layer or central region of a composite, structural, or mechanical component. In transformers, inductors, and electric motors, core thickness refers to the physical dimensions of the magnetic core, frequently specifically the thickness of individual steel laminations.
Core thread – It is normally known as the minor diameter or root diameter. It is the smallest diameter of a screw thread, measured across the bottom roots of an external thread (like a bolt) or the tips of an internal thread (like a nut). It is the diameter of an imaginary cylinder which that touches the lowest points (roots) of an external screw thread.
Core truck – It is a specialized wheeled cart, truck, or carriage used to safely transport fragile sand cores from the core-making room to the moulding or baking floor.
Core tube – It is the central collection of internal tubes (straight or U-shaped) in a shell-and-tube heat exchanger through which hot or cold fluid flows. It is also a hollow steel tube or barrel (such as a rotary or gravity corer) used to extract undisturbed cylindrical soil or rock samples from the ground or seabed.
Core values – These are the fundamental beliefs, guiding principles, and non-negotiable standards which shape how an individual or organization behaves, makes decisions, and prioritizes what matters most.
Core vents – These are a wax product, round or oval in form, used to form the vent passage in a core. It is also a metal screen or slotted piece used to form the vent passage in the core box used in a core blowing machine. These are also the holes made in the core for the escape of gas.
Core volume – It is the physical or effective volume of the ferro-magnetic material (such as ferrite or cold-rolled grain-oriented silicon steel) used in transformers, inductors, or stabilizers. It dictates energy storage capacity, flux density, and core losses.
Core wall – It is a vertical, high-strength structural element, typically made of reinforced concrete—positioned at the central core of a high-rise or supertall building to act as its main mechanical and stability back-bone.
Core wall system – It is a vertical structural element in high-rise and supertall buildings made of interconnected reinforced concrete walls which act as a central spine to resist lateral loads like wind and earthquakes.
Core wash – It is a suspension of a fine refractory applied to cores by brushing, dipping, or spraying to improve the surface of the cored portion of the casting.
Core, wave-guide – Wave-guide core is the central region of an optical waveguide which has a larger refractive index than the surrounding media, allowing light-waves to be confined and propagate along it.
Core wires – These are also called core rods or core rolls. These are reinforcing wires or rods for fragile cores, frequently preformed into special shapes.
Corex process – The main feature of the Corex process is the separation of the iron reduction and smelting operations into two separate reactors, namely reduction shaft and melter-gasifier. In the two-stage operation of the process direct reduced iron produced from a shaft furnace is charged into a melter-gasifier for smelting. In the melter-gasifier, non-coking coal is gasified by injecting oxygen and pre-reduced iron ore / pellets are melted. The outgoing gas is used for reduction of iron ore / pellets in the upstream shaft furnace.
Core zone – In structural engineering, it is the region within the cross-section of a structural member (such as a column or footing) where an axial load can be applied without producing any tensile stresses in the section. Keeping the load inside this zone ensures the entire section stays under compression, which is vital for brittle materials like concrete that have low tensile strength. In building and construction engineering, core zone is the central load-bearing and functional shaft of a multi-story or high-rise building.
Coring – It is a condition of variable composition between the centre and surface of a unit of micro-structure (such as a dendrite, grain, carbide particle). It results from non-equilibrium solidification, which occurs over a range of temperature. It is also a central cavity at the butt end of a rod extrusion, sometimes called extrusion pipe.
Coring operation – It is a drilling process which uses a hollow, cylindrical drill bit to extract an undisturbed, solid column of material (a core) from sub-surface rock, soil, or hardened structures like concrete and asphalt. It refer to the processes of collecting core samples from geological formations, particularly gas hydrate reservoirs, while maintaining pressure and temperature conditions to ensure the stability of the samples for further analysis. These operations utilize various coring technologies to preserve the integrity of gas hydrates during sampling.
Coring up – It means placing preformed sand or metal inserts (called cores) into the mould cavity before closing the mould halves. This process ensures the final metal casting has the correct internal hollow spaces, undercuts, or complex shapes.
Coriolis acceleration – It is the acceleration experienced by a fluid mass moving relative to a rotating coordinate system, resulting from the interaction between the fluid’s velocity and the earth’s rotational speed. It causes a deflection of fluid particles, with movement to the right in the northern hemisphere and to the left in the southern hemisphere.
Coriolis effect – It is an apparent (fictitious) acceleration or force acting on a moving object within a rotating frame of reference, at right angles to both the object’s velocity and the axis of rotation. Instead of dealing strictly with planetary rotation (like weather systems), mechanical and civil engineers apply this principle to design and operate precision instruments.
Coriolis flowmeter – It is an industrial measurement device that determines the mass flow rate of liquids and gases directly by utilizing the Coriolis effect in vibrating tubes. Unlike volumetric flowmeters, it measures actual mass without being affected by changes in fluid density, pressure, temperature, or viscosity.
Coriolis force – It is an apparent or fictitious inertial force which acts on a moving object within a rotating frame of reference.
Coriolis meter – It is also called Coriolis mass flowmeter. It is a device which directly measures the mass flow rate, density, and temperature of liquids, gases, or slurries passing through a pipe.
Coriolis parameter – It quantifies the local vertical component of the earth’s rotation rate which affects moving objects or fluid flows in a rotating reference frame.
Corium – It is a lava-like, high-temperature mixture of nuclear fuel, fission products, control rods, structural metals, and melted concrete that forms during a severe nuclear reactor meltdown. It refers to complex materials formed as a result of nuclear accidents, containing a wide range of elements and compounds associated with nuclear fuels. These materials undergo aging which can alter their physical and chemical properties, affecting their treatment and decommissioning processes.
Corner – It is a convex arc which tangentially joins two intersecting sides at an external angle of more than 180-degree. Corners serve to join the sides of a rib or boss with its peak or land. A full-rounded or full-radiused top of a rib is made up of two continuous corners which are tangential to the sides of the rib and to each other, and that blend symmetrically to form a convex, essentially semi-circular arc.
Corner cracks – These are cracks present as a defect in the edge of the continuous cast steel product. They appear due to high temperature variations in the liquid steel, higher aluminum content in the steel, higher sulphur level in the steel, non-uniform edge temperature, excess friction in the edges during casting because of non-uniform distribution of casting powder, and lower superheat of the steel.
Corner defect – It is the missing corner of a brick defined by three dimensional measurements.
Corner flange weld – It is a flange weld with only one member flanged at the joint.
Corner fill – It refers to the extent to which a material completely flows into, expands within, or occupies the tight corner apex of a mould, die, or joint during a manufacturing process.
Corner frequency – is the specific frequency where a circuit or filter’s output power drops to half its maximum value. It is also known as the -3 dB point. It is the frequency at which the noise spectral density begins to rise in the context of 1/f noise, indicating a transition in the noise characteristics of an amplifier. It serves as a figure of merit, with lower corner frequencies suggesting better performance in low-frequency low-noise applications.
Cornering force – It is also known as side force. It is the lateral (sideways) force produced by a vehicle tyre parallel to the wheel axis while navigating a turn. It acts to counteract centrifugal force and keep the vehicle on its intended trajectory.
Cornering stiffness – It is the rate of lateral (side) force a tyre generates per unit of slip angle when cornering in the linear region near zero slip angle. It measures how quickly a tyre builds up cornering grip as the wheel turns at a small angle relative to its actual direction of travel.
Corner joint – It is a joint between two members located approximately at right angles to each other.
Corner node – It is very frequently used in finite element analysis (FEA) and structural grids, It is a main vertex point located at the geometric corner or apex of a finite element or domain mesh.
Corner radius – It is the rounded arc or curvature which replaces a sharp 90-degree angle where two surfaces or edges meet.
Corner radius ratio – It is the ratio of the corner radius of a rectangular or square cross-section to the overall width or dimension of that section.
Corner reflector – It is a passive retroreflective device made of mutually perpendicular, intersecting conducting or optical surfaces which reflects incoming electro-magnetic waves (such as radio waves, microwaves, or light) directly back along the exact same path toward the source.
Corners and fillets – These are curved connecting surfaces on closed-die forgings which unite smoothly the converging or intersecting sides of forged elements, such as ribs, bosses, and webs. Their radii provide a smooth, gradual connection rather than an abrupt angular junction. Corners and fillets are defined and described by their transverse directions.
Corner-slick – It is a hand tool used by moulders in a metal casting foundry to repair, smooth, and shape sand moulds, specifically around inside and outside corners, before molten metal is poured.
Corner turn-up – It is a distortion, buckle, or twist condition which causes the corner(s) of the sheet to deviate from a perfectly flat plane on which it rests.
Corona – In resistance welding, it is the area sometimes surrounding the nugget of a spot weld at the faying surfaces which provides a degree of solid-state welding. In electrical terms, corona refers to a phenomenon of partial electrical discharge where air around a high-voltage conductor becomes ionized, creating a visible glow, audible hissing or humming, and ozone production. This occurs when the electric field strength at the conductor’s surface exceeds the critical value required for air breakdown.
Corona discharge – It refers to an electrical phenomenon where a high-voltage conductor ionizes the surrounding air, causing a visible glow and frequently a hissing or crackling sound. This occurs when the electric field around a conductor becomes strong enough to overcome the dielectric strength of the air, leading to a partial breakdown and ionization.
Corona discharge treatment – It is a widely used process for oxidation which improves the bondability, wettability, and printability of polymers, particularly polyolefin films, by introducing oxygen- or nitrogen-containing groups onto their surfaces.
Corona loss – It is the power dissipated because of the corona discharge in high voltage power transmission lines. This discharge occurs when the electric field around a conductor becomes strong enough to ionize the surrounding air, leading to a partial breakdown of the air and the loss of energy in the form of light, heat, and sound.
Corona treatment – It is an industrial surface modification technique which uses a high-voltage, high-frequency electrical discharge (a corona) to ionize the surrounding air and alter the outermost molecular layer of a substrate.
Corona voltage = It is frequently split into disruptive critical voltage and visual critical voltage. It is the threshold voltage level at which the local electric field around a high-voltage conductor exceeds the dielectric strength of the surrounding air, causing it to ionize and turn partially conductive.
Corotating screw – It refers to a twin-screw configuration, very frequently found in twin-screw extruders, where two parallel screws rotate in the exact same direction (either both clockwise or both counter-clockwise).
Corotational rate – It refers to a derivative of stress which is invariant to rigid spin, differing from the ordinary material rate by terms which are linear in the product of stress and the velocity gradient. It is used when large deformation or rotation occurs in a solid, ensuring accurate representation of the material’s behaviour under such conditions.
Corporate average fuel economy – It is a regulatory standard which sets a sales-volume weighted average requirement for fuel efficiency or carbon di-oxide (CO2) emissions across an automotive manufacturer’s entire fleet of vehicles, rather than on a per-model basis.
Corporate communication – It is also known as public relations. Its primary objective is to establish a good perception (true or otherwise) in the eyes of the public and its stakeholders since the fortune of the organization is influenced by the assessment of the public and the stakeholders. Corporate communication is a way for the organization to heighten and strengthen its position. It normally involves communicating with the media or professionals to introduce the organization in the most impressive way possible. It also involves coordinated efforts between independent society and the organization to create kindness within the society and propagate the image of the organization. It is to ensure through press releases, newsletters, advertisements and other modes of communication that the public and stakeholders gets only that information which the organization wants them to have. It is the managing of relationships with public groups. It is all about managing relationships by informing, persuading, dialogue, and negotiating and is considered as an important tool of the organizational management. It is done to influence the behaviour of parts of the important relationships.
Corporate culture – It is the shared set of values, beliefs, attitudes, and unwritten rules which dictate how people interact and work within the organization. Frequently called the ‘personality’ of the organization or ‘how employees do things around here’, it shapes everything from daily communication and decision-making to employee well-being and organizational success.
Corporate social responsibility – It is the voluntary actions which the organization takes, over and above compliance with minimum statutory and legal requirements, to address both its own competitive interests and the interests of wider society. The obligation of the organization is to maximize its positive impact and minimize its negative impact on the society. Corporate social responsibility typically includes ‘beyond statutory requirements’ commitments and activities pertaining to (i) corporate governance and ethics, (ii) health and safety, (iii) environmental stewardship, (iv) human rights (including core labour rights), (v) sustainable development, (vi) and conditions of work (including safety and health, hours of work, and wages etc.), (vii) employee relations, (viii) community involvement, development and investment, (ix) involvement of and respect for diverse cultures and disadvantaged peoples, (x) corporate philanthropy and employee volunteering, (xi) customer satisfaction and adherence to principles of fair competition, (xii) anti-bribery and anti-corruption measures, (xiii) accountability, transparency. and performance reporting, and (xiv) supplier relations, for both domestic and international supply chains.
Correct classification rate (CCR) – It is also known as classification accuracy. It is the ratio of correctly classified objects or samples to the total number of objects in a test dataset. ‘CCR = (TP + TN) / (TP + FP + FN + TN)’, where TP is true positives which are correctly predicted positive instances, TN is true negatives which are correctly predicted negative instances. FP is false positives, which are incorrectly predicted positive instances (Type I error), and FN is false negatives which are incorrectly predicted negative instances (Type II error).
Corrected mass flow – It is the actual mass flow rate passing through a turbocharger, compressor, or engine inlet scaled to what that flow rate is under standard sea-level atmospheric conditions.
Correcting system – It is a subsystem or component which modifies an output or process to compensate for errors, disturbances, or acoustic / physical variations, hence restoring the system to a desired state, response, or flat bench-mark.
Correction code – It is the error correction code (ECC) or forward error correction (FEC). It is a mathematical technique used to detect and self-correct data corruption in digital communication and storage systems.
Correction element – It is also called a final control element. It is the component in a closed-loop control system which transforms a controller’s output signal into a physical change in the process to fix or adjust the controlled variable.
Correction equation – It is a mathematical adjustment applied to a theoretical model, calculation, or measured value to compensate for systematic errors, non-ideal conditions, or simplifications made in primary equations.
Correction factor – It is a multiplier (or an additive adjustment value) applied to a theoretical calculation, design formula, or raw measurement to account for known systematic errors, non-ideal real-world conditions, or geometric / material deviations.
Correction formula – It is a mathematical adjustment applied to a measured value or an idealized model to compensate for known systematic errors or real-world deviations.
Correction learning – It is a method in which weights are adjusted based on the error recovered, specifically the difference between the calculated and actual values, and is mainly used in supervised learning to minimize overall error during iterations.
Correction procedure – It is a systematic method used to adjust measured data, calculations, or physical processes to eliminate known errors, systematic biases, or deviations from ideal models.
Correction signal – A correction signal is the signal used to control power to the actuator to set the level of the input variable.
Correction term – It is a numerical value, multiplier, or additive offset applied to an equation, model, or measurement to compensate for systematic errors, real-world constraints, or unmodeled physical effects.
Corrective action – A step taken to bring work back into alignment with performance expectations after it has failed to meet expectations. A corrective action, which is reactive, is not the same as a preventive action, which is proactive.
Corrective effective temperature chart – It is a graphical tool used to plot environmental data, such as air temperature, humidity, and air velocity, yielding an adjusted temperature reading which accurately reflects how hot workers feel. It helps assess and manage severe thermal stress conditions typical around high-heat operations.
Corrective maintenance – It consists of the maintaining action for correcting or restoring a failed unit. It is the maintenance which is carried out following detection and aimed at restoring normal operating conditions. This approach is based on the firm belief that the costs sustained for downtime and repair in case of fault are lower than the investment needed for a maintenance programme. However, this strategy is only good until catastrophic faults occur and all savings are gone. Corrective maintenance has a very vast scope for small actions such as adjustment, minor repairs to redesign of equipments. It is normally carried out in four steps namely (i) collecting the data, information, and analysis, (ii) identifying the causes, (iii) finding out the best possible solution to eliminate likely causes, and (iv) implementing the solutions.
Correct operation – It refers to the performance of a machine, system, procedure, or process in exact accordance with established standards, instructions, or optimal design parameters.
Corrector – It is a device, algorithm, or component which adjusts an initial estimate, signal, or process variable to reduce error, match a target law, or improve accuracy.
Correlated channel – It is a communication path where the fading characteristics, signals, or sub-channels are statistically dependent on one another rather than acting independently.
Correlated equilibrium – It is a solution concept where a mediator, algorithm, or public signal probabilistically recommends actions to players, and no player benefits from unilaterally deviating from their assigned recommendation.
Correlated random variables – These are random variables which show a statistical dependence where a change in the value of one variable relates to or influences the value of another.
Correlated Rayleigh – It refers to a type of fading channel characterized by receive correlations which affect the mutual information and capacity, with the optimal input covariance matrix depending on the correlation structure of the channel. In this context, increased receive correlation improves the beamforming optimality range.
Correlated Rayleigh model – It describes a multipath fading channel where the received signal envelopes follow a Rayleigh distribution, but the underlying Gaussian sub-components (in-phase and quadrature-phase signals) or multiple antenna branches possess a spatial or temporal correlation structure rather than being completely independent.
Correlated result – It refers to an outcome or measurement from a model, simulation, or test environment which matches and aligns consistently with empirical data from a physical prototype, benchmark, or separate testing platform.
Correlated sequence – It refers to multiple data sequences, signals, or time-series measurements which show statistical dependencies or relationships with one another, allowing for joint prediction or analysis based on their interrelated patterns.
Correlated value – It refers to a statistical measure which quantifies the strength and direction of the relationship between two or more engineering variables, system parameters, or experimental datasets.
Correlates – It refers to the statistical relationships between two variables, indicating how changes in one variable can account for changes in another, frequently measured by the Pearson linear correlation coefficient (r). However, correlations can be misleading, as they do not imply direct causation and cannot reflect nonlinear relationships or external influencing factors.
Correlation – It is a statistical measure which describes the relationship or connection between two variables.
Correlation and regression – These are statistical tools used to study the relationship between variables. Correlation measures the strength and direction of an association between two variables, while regression builds a mathematical model to predict the value of a dependent variable based on one or more independent variables.
Correlation coefficient – It is a decimal number between 0.00 and +/- 1.00 which indicates the degree to which two quantitative variables are related. The most common one used is the ‘Pearson product moment’ correlation coefficient or just the Pearson coefficient. It indicates the strength and direction of linear association between two quantitative variables.
Correlation detection – It is a signal-processing and analytical method which measures the similarity between two signals or compares a known reference signal against an incoming observation to determine if a target pattern is present.
Correlation detector – – It is a signal-processing device or algorithm which measures the similarity between an incoming observed signal and a known reference wave-form (or template). It is a discrete-time matched filter which correlates a signal with the observation, producing a high output value when the correlation is strong.
Correlation force – It normally refers to a force arising from statistical or quantum-mechanical correlations between particles or defects in a system.
Correlation matrix – It is a square table (m x m) which displays the pair-wise linear correlation coefficients between multiple variables, signals, or datasets. It isa symmetric matrix that represents the mutual correlations among a set of variables, where the diagonal elements are unit values and the off-diagonal elements indicate the strength of the relationships between pairs of variables.
Correlation method – It refers to either a statistical technique used to quantify the relationship between two or more system or material variables, or an optical measurement technique like digital image correlation (DIC) used to track full-field surface displacement and strain under load.
Correlation model – It is a mathematical or statistical representation which quantifies the strength and direction of the relationship between two or more system variables (such as material properties, loads, or performance metrics).
Correlation process – It is a systematic method used to match, align, or compare data, signals, or physical test results to ensure consistency, validate models, or measure similarity.
Correlation region – It normally refers to a localized spatial, structural, or domain boundary within a material or system, in which physical properties, fluctuations, or responses (such as magnetic domains, crystal grains, or optical wavefront sub-images) act in a highly synchronized or interdependent manner.
Correlator – It is an electronic device which provides the averaged product of intensity fluctuations from multiple signals, normalizing these by the average intensities to get correlation functions used in high-speed photon counting and intensity interferometry. It processes photon-count data in real time, enabling the analysis of signals that are often a small fraction of the total noise present in the data.
Correspondence relationship – It defines how elements in different models, documents, or systems link together. It specifies that a component in one artifact relates to, depends on, or implements a component in another artifact.
Corroded area – It is the specific region or surface extent on a material, normally a metal, where chemical, electro-chemical, or environmental degradation has caused material loss, wall thinning, or physical damage.
Corroded pipeline – It is a steel or metal pipeline which has suffered structural deterioration and metal loss because of the chemical or electro-chemical reactions with its surrounding environment or the fluid it transports.
Corrodkote test – The Corrodkote test is an accelerated test used for determining plating corrosion resistance of electro-deposits. It is performed by putting Corrodkote mud as well as a dried sample under testing within a moist chamber.
Corrosion – It is the wasting away of metal because of chemical action. It is the chemical or electro-chemical reaction between a material, normally a metal, and its environment which produces a deterioration of the material and its properties. In case of galvanized steel, zinc chemically reacts with elements in the atmosphere, thereby sacrificially corroding to prevent corrosion of the underlying steel. In a boiler, it is normally caused by the presence of oxygen, carbon di-oxide, or an acid. In refractories, corrosion is the surface wear caused by the chemical action of external agencies.
Corrosion allowance – It is the extra metal thickness added to the calculated minimum required wall thickness of a component (such as a pressure vessel, pipe, or offshore structure) to compensate for expected material loss from corrosion, erosion, or mechanical wear over its operational lifespan.
Corrosion attack – It is the destruction or deterioration of a material (normally a metal or alloy) caused by a chemical or electro-chemical reaction with its surrounding environment.
Corrosion behaviour – It refers to how a material (normally a metal or alloy) responds, degrades, or interacts chemically and electro-chemically when exposed to a specific environment.
Corrosion control – It refers to the methods and processes used to prevent and manage corrosion by practices which evaluate designs for dissimilar metals, material properties in corrosive environments, and other factors contributing to corrosive degradation.
Corrosion coupon – It is also known as a weight-loss or mass-loss coupon. It is a small, pre-weighed piece of metal or alloy made from a material identical or closely matching the system being monitored (such as a pipeline, water treatment loop, or chemical reactor). It is inserted directly into the process environment for a set period (typically 30 days to 120 days), removed, cleaned, and re-weighed to measure metal loss, evaluate corrosion rates, and check for localized issues like pitting or scaling.
Corrosion cracks – These cracks are very frequently known as stress corrosion cracking (SCC). These cracks refer to fine, branching cracks which grow when a metal experiences simultaneous tensile stress and a corrosive environment.
Corrosion damage – It is the deterioration of a material’s performance, functional properties, or structural integrity resulting from physico-chemical or electro-chemical interactions with its environment.
Corrosion defect – It is a localized or general metal loss feature or structural degradation caused by the chemical, electro-chemical, or biological reaction between a material and its surrounding environment.
Corrosion depth – It is the measure of material loss from a metal surface because of the chemical or electro-chemical deterioration over a given time.
Corrosion effect – It is a change in any part of the corrosion system caused by corrosion.
Corrosion embrittlement – It is the severe loss of ductility of a metal resulting from corrosive attack, normally inter-granular and frequently not visually apparent.
Corrosion engineering – It is an engineering specialty which applies scientific, technical, engineering skills, and knowledge of natural laws and physical resources to design and implement materials, structures, devices, systems, and procedures to manage corrosion. Corrosion and corrosion engineering involves a study of chemical kinetics, thermodynamics, electro-chemistry and materials science.
Corrosion-erosion – It is a conjoint action involving corrosion and erosion in the presence of a moving corrosive fluid, leading to the accelerated loss of material.
Corrosion, exfoliation – It is the corrosion which progresses approximately parallel to the metal surface, causing layers of the metal to be elevated by the formation of corrosion product.
Corrosion failure of refractories – It is the most common cause of premature failures of refractories. However, corrosion is infrequently the cause of premature failure for technical ceramics. Corrosion of refractories occurs mainly when refractory materials are in contact with metallurgical slags or glasses (solids + liquid type of reaction), but atmosphere corrosion also occurs under specific circumstances (under reducing or oxido-reducing conditions), as, for example, under attack from carbon mono-oxide or alkalis and other condensable gases (solid + gas type of reaction).
Corrosion fatigue – It is the process in which a metal fractures prematurely under conditions of simultaneous corrosion and repeated cyclic loading at lower stress levels or fewer cycles than are needed in the absence of the corrosive environment.
Corrosion fatigue failure – It is the premature fracture of a metal caused by the simultaneous action of a corrosive environment and repeated cyclic mechanical loading (such as vibration, bending, or pressure fluctuations) at stress levels well below the material’s normal endurance limit or yield strength.
Corrosion fatigue strength – It is the maximum repeated stress which can be endured by metal without failure under definite conditions of corrosion and fatigue and for a specific number of stress cycles and a specified period of time.
Corrosion, galvanic – It is the corrosion which is associated with the current of galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes. A metal corrodes if it is anodic to the dissimilar metal.
Corrosion index – It is a number expressing the maximum depth in micrometers to which corrosion penetrates in one year on the basis of a linear extrapolation of the penetration occurring during the lifetime of a given test or service.
Corrosion inhibiting compound – It is a chemical substance or formulation that, when applied to a metal surface or added to a surrounding fluid or gas, considerably reduces or prevents the rate of metal corrosion.
Corrosion-inhibiting primer – It is a specialized base coat applied to metal surfaces. such as steel or aluminum alloys, which contains active chemical compounds or sacrificial pigments to stop oxidation and protect the underlying substrate from moisture and air.
Corrosion inhibitor – It is the substance which retards some specific chemical reaction causing corrosion.
Corrosion initiation – It is the initial phase of metal degradation where aggressive agents (such as chlorides or carbon di-oxide) reach the surface of a metal or embedded reinforcement, break down its protective passive film, and start the active corrosion process.
Corrosion, intergranular – It is the corrosion which is occurring preferentially at grain boundaries. It is also termed as inter-crystalline corrosion.
Corrosion mechanism – It is the physical-chemical interaction between a material (normally a metal) and its environment which causes the material to degrade, lose its structural properties, or revert to a more thermodynamically stable state like an oxide, sulphide, or carbonate.
Corrosion model – It is a predictive tool or mathematical representation used to assess how and how fast materials (mainly metals) degrade because of the chemical, electro-chemical, or environmental interactions.
Corrosion monitor – It is a device, instrument, or program used in engineering to measure and track the rate of metal degradation, material loss, and environmental aggressiveness in operational equipment and pipelines.
Corrosion monitoring system – It is an integrated arrangement of sensors, probes, data loggers, and analytical tools used to continuously or periodically measure, track, and evaluate metal degradation rates (such as wall thickness loss or corrosion speed) in industrial equipment, pipelines, and structures. Unlike periodic inspection, which provides a static, point-in-time snapshot of damage, a monitoring system acts as an early warning network to predict remaining asset life, verify the effectiveness of chemical inhibitors or cathodic protection, and prevent catastrophic failures.
Corrosion of cobalt alloys – It refers to the chemical or electro-chemical degradation of cobalt-based metal matrices when exposed to hostile aqueous, high-temperature, or bodily environments, mitigated mainly by the formation of a protective passive chromium-oxide surface film.
Corrosion of nickel and nickel alloys – It refers to how these metallic materials resist or undergo chemical and electro-chemical degradation when exposed to aggressive environments like acids, alkalis, or high-temperature gases.
Corrosion penetration rate – It is the thickness loss of material per unit of time as a result of corrosion; normally expressed in terms of millimeters per year.
Corrosion pit – It is a small, localized cavity or hole which forms on a metallic surface when protective oxide layers break down, causing the material to dissolve inward at a rate much faster than the surrounding bulk surface.
Corrosion, pitting – It is the localized corrosion which results in small pits or crater in a metal surface.
Corrosion potential (Ecorr) – It is the potential of a corroding surface in an electrolyte, relative to a reference electrode. It is also called rest potential, open-circuit potential, or freely corroding potential.
Corrosion potential measurement – It is an electro-chemical engineering technique used to determine the electrical potential of a freely corroding metal surface relative to a stable reference electrode when no net external current is applied.
Corrosion prevention – It refers to the design processes, material choices, and protective measures used to stop, slow down, or manage the chemical and electro-chemical degradation of metals and structures. Since complete corrosion resistance is rarely possible, engineers implement targeted strategies to extend the safe operating life of machinery, vehicles, and infrastructure.
Corrosion probability – It is the statistical likelihood or chance which corrosion is going to initiate or occur in a material or structural component over a given time frame, under specific environmental and operational conditions.
Corrosion problems – These problems refer to the degradation of materials, typically metals, because of their reaction with the environment, leading to substantial economic losses and potential structural failures that impact safety and the environment.
Corrosion products – These products refer to the by-products generated during the corrosion of a metal, which can include insoluble hydro-oxides, carbonates, oxides, sulphides, silicates, and borates which form films on the metal’s surface. These products can influence the protective characteristics of the metal, with some forming porous films which allow further corrosion and others forming tight, adherent films which protect against corrosion.
Corrosion product deposit – It in engineering refers to the accumulated solid materials, such as oxides, hydro-oxides, carbonates, sulphides, or silicates, which form on a metal surface as a direct result of chemical or electro-chemical corrosion processes.
Corrosion property – It refers to the intrinsic characteristic or susceptibility of a material (typically a metal or alloy) to degrade, deteriorate, or lose structural integrity due to chemical or electrochemical reactions with its surrounding environment. It describes how a material interacts with corrosive agents, such as moisture, oxygen, acids, salts, or microbial activity, over time.
Corrosion protection – It is the modification of a corrosion system so that corrosion damage is mitigated.
Corrosion rate – It is the corrosion effect on a metal per unit of time. The type of corrosion rate used depends on the technical system and on the type of corrosion effect. Hence, corrosion rate can be expressed as an increase in corrosion depth per unit of time (penetration rate, for example, millimeter or micrometer per year) or the mass of metal turned into corrosion products per unit area of surface per unit of time (weight loss, for example, grams per square metre per year). The corrosion effect can vary with time and cannot be the same at all points of the corroding surface. Hence, reports of corrosion rates are to be accompanied by information on the type, time dependency, and location of the corrosion effect.
Corrosion rate model – It is a mathematical representation or predictive tool used to calculate or estimate the speed at which a material (typically metal) deteriorates over time because of the chemical or electro-chemical reactions with its environment.
Corrosion reaction – It is the destructive, irreversible chemical or electro-chemical process in which a material (very frequently a metal or alloy) interacts with its surrounding environment, leading to its gradual degradation, material loss, or functional impairment.
Corrosion, refractories – It is the destruction of refractory surfaces by the chemical action of external agencies.
Corrosion repair – It is the process of restoring the structural integrity, mechanical strength, and functional properties of materials (such as metals, alloys, or reinforced concrete) which have degraded because of the chemical, electro-chemical, or environmental oxidation.
Corrosion resistance – It is the ability of a material to withstand contact with ambient natural factors or those of a particular, artificially created atmosphere, without degradation or change in properties. For metals, this can be pitting or rusting, while for organic materials it can be crazing.
Corrosion resistance of cobalt-chromium alloy – Corrosion resistance is the ability of cobalt-chromium alloy to withstand chemical degradation and oxidation through the formation of a self-healing, protective passive chromium oxide surface layer.
Corrosion resistant alloy – It consists of non-ferrous based alloy in which any one of the sums of the specific quantity of the elements namely titanium, nickel, cobalt, chromium, and molybdenum exceed 50 % in weight.
Corrosion-resistant plates – These are specialized metallic flat sheets to withstand environmental degradation, oxidation, and chemical attack. These are flat metal sheets made from alloys (like stainless steel or nickel-based metals) which resist rust and chemical breakdown far better than standard carbon steel.
Corrosion services – These are specialized technical practices focused on preventing, controlling, and managing the deterioration of materials and metals caused by chemical or environmental reactions.
Corrosion, stress-cracking – It is the failure by cracking resulting from selective directional attack caused by the simultaneous interaction of sustained tensile stress at an exposed surface with the chemical or electro-chemical effects of the surface environment. The term frequently is abbreviated SCC, which correctly stands for stress-corrosion cracking.
Corrosion study – It is a systematic evaluation that analyzes the degradation characteristics, mechanisms, and expected rates of materials, mainly metals, when interacting with their operating environment.
Corrosion system – It is the system consisting of one or more metals and all parts of the environment which influence corrosion.
Corrosion, water stain – It is the superficial oxidation of the surface with a water film, in the absence of circulating air, held between closely adjacent metal surfaces.
Corrosion wear – It is material loss caused by the combined action of chemical or electro-chemical reactions with the environment and mechanical sliding or rubbing. Chemical attack creates a brittle surface film, and friction quickly scrapes it away, exposing fresh metal to repeat the cycle.
Corrosive atmosphere – It is a surrounding gas or air environment which causes the degradation, destruction, or weakening of materials (normally metals) through chemical or electro-chemical reactions.
Corrosive attack – It is the destructive deterioration or progressive loss of a material (typically a metal or alloy) caused by direct chemical or electro-chemical reactions with its environment.
Corrosive effect – It is the gradual destruction or degradation of a material (typically metals, polymers, or concrete) caused by chemical, electro-chemical, or biological interactions with its surrounding environment.
Corrosive environment – It is a surrounding atmosphere, fluid, or soil condition which chemically or electro-chemically degrades and destroys materials, very frequently metals, over time.
Corrosive nature – It describes the tendency of a substance to undergo gradual destruction, normally through chemical or electro-chemical reactions. when it interacts with its surrounding environment.
Corrosive wear – It is the wear in which chemical or electro-chemical reaction with the environment is important. It is defined as the degradation of materials in which both corrosion and wear mechanisms are involved. The combined effects of wear and corrosion can result in total material losses which are much higher than the additive effects of each process taken alone, which indicates synergism between the two processes.
Corrosive wear failure – It is the failure of a material because of corrosion wear.
Corrosivity – It is the tendency of an environment to cause corrosion in a given corrosion system. It is the chemical capacity of a substance to wear away, dissolve, or irreversibly destroy other materials upon contact.
Corrosivity categories – These categories refer to classifications which describe the potential for corrosion in different environments, based on factors such as climate and local conditions, which influence corrosion rates and protective measures needed for structures.
Corrugated belt – It is a conveyor belt featuring a corrugated profile for enhanced flexibility and improved material containment. It needs checks for wear patterns and proper alignment.
Corrugated galvanized iron – It is corrugated galvanized steel sheet. It is a building material composed of sheets of hot-dip galvanized mild steel, cold-rolled to produce a linear ridged pattern in them. The corrugations increase the bending strength of the sheet in the direction perpendicular to the corrugations, but not parallel to them, since the steel is to be stretched to bend perpendicular to the corrugations. Normally each sheet is manufactured longer in its strong direction.
Corrugated iron – It is a building material made from thin sheets of iron or steel which are cold-rolled or pressed to form a series of parallel, wave-like ridges and grooves.
Corrugated land – It is also called road corrugation or wash boarding. It refers to a surface defect on unpaved dirt or gravel roads featuring a repeating pattern of parallel ridges and hollows transverse to the direction of travel.
Corrugated panel – It is a structural sheet or core featuring a repeating, periodic pattern of alternating ridges (crests) and valleys (troughs).
Corrugated profile – It is a structural design featuring a repeating pattern of alternating ridges (crowns) and valleys (troughs) pressed or rolled into a material.
Corrugated shape – It is a structural configuration featuring a repeating pattern of parallel ridges and valleys (or flutes, ripples, and furrows).
Corrugated sheet – It is a generic term which means any type of sheet steel strengthened for use in construction by having a series of alternating grooves and ridges forced into it. Technically, this can mean any metal roofing or wall panel.
Corrugated side wall conveyor belt – Conveyor belt equipped with special waves or cleats called corrugated sidewall on the belt provides the features such as (i) corrugated sidewall design allowing for greater transport volume with increased sectional loading area, enabling a narrower conveyor design, (ii) reducing the foot space as steep incline or vertical transport is possible with cleats attached belt width wise, (iii) no skirt board is needed as transport materials spillage is prevented by high wave like raised strip, (iv) incline angle can be easily adjusted with specially strong belts and press rollers, and (v) flat rollers can be used to reduce the equipment cost.
Corrugated track – It refers to a type of railway track which shows periodic surface irregularities known as corrugations, which can be categorized into short-pitch (wave-lengths of 30 millimeters to 90 millimeters) and long-pitch (wave-lengths of 150 millimeters to over 500 millimeters) types, each caused by different mechanical interactions and stresses between the wheels and rails.
Corrugated web girder – It is a specialized structural beam or plate girder which features a folded or corrugated metal sheet (typically trapezoidal or sinusoidal) as its central web, positioned between two parallel top and bottom flanges.
Corrugating – It is the forming of sheet metal into a series of straight, parallel alternate ridges and grooves with a rolling mill equipped with matched roller dies or a press brake equipped with a specially shaped punch and die.
Corrugations – In metal forming, these are transverse ripples caused by a variation in strip shape during hot or cold reduction.
Corrupted signal – It is an electrical, optical, or digital signal which has been considerably altered, degraded, or mixed with unwanted elements, such as noise, distortion, attenuation, or interference, making the original data or wave-form difficult or impossible for a receiver to interpret accurately.
Corrupted noise – It refers to unwanted, random, or external disturbances which mix with, distort, or mask a desired physical, electrical, or digital signal. When noise corrupts a signal, it alters the original wave-form, data packets, or image quality, making the true information harder for receivers or processors to extract accurately.
Corrupting noise – It refers to any unwanted, random, or extraneous disturbance that alters, masks, or degrades an information-carrying signal, image, or dataset during capture, transmission, storage, or processing.
Corten steels – These steels are distinguished by their high weather resistant properties. The alloying of steel with copper and chromium ensures the formation of a firmly adhering protective layer of rust which protects the steel from corrosion in atmospheric condition. The protective layer of rust also makes an attractive appearance on the steel surface.
Cortex core – It refers to a 32-bit microprocessor core, part of a series of ARM (advanced RISC machine) processors, that includes features such as an arithmetic logic unit (ALU), pipelining for instruction processing, and an interrupt interface, designed for various applications including embedded systems.
Cortex model – It is a suite of managed, in-database large language models (LLMs) and AI / ML (artificial intelligence / machine learning) functions which let engineers run vector searches, text generation, and SQL (structured query language) transformations directly on governed data inside a platform.
Corundum – Corundum is a crystalline form of aluminium oxide typically containing traces of iron, titanium, vanadium, and chromium. It is an aluminum oxide which normally forms hexagonal barrel-shaped prisms which taper at both ends or as thin tabular hexagonal plates. It has a hardness of 9 on the Mohs scale. It has no dominant cleavage and it fractures in a conchoidal manner. It is used as an abrasive.
Cosh – It means hyperbolic cosine. It is a mathematical function defined as the average of the exponential function and its inverse.
Cosh and sinh – These terms mean hyperbolic cosine and hyperbolic sine. These are mathematical functions built from natural exponential terms which describe exponential growth, decay, and geometry tied to hyperbolas rather than circles.
Cosine function – It is defined as the ratio of the length of the adjacent side to the hypotenuse in a right-angled triangle, or as the x-coordinate of a point on the unit circle.
Cosine wave – It is a smooth, periodic wave-form which starts at its peak value of +1 at time zero and oscillates continuously between +1 and -1.
Coslettizing – It is producing a black, rust-resisting surface on iron and steel by boiling for some hours in water containing phosphoric acid and iron filings.
Cosmic microwave background radiation – It is the remnant radiation from the early universe which provides strong evidence for the big bang model of cosmology and contains information on different cosmological parameters, including the universe’s geometry and density.
Cosolvent – It is a pure organic solvent added to a main solvent, typically water, to change the properties of the solution or to dramatically increase the solubility of a poorly soluble solute.
Cosserat continuum – It is a theoretical framework which describes the mechanical behaviour of materials with micro-structure, allowing for the consideration of additional degrees of freedom such as rotations and couple stresses in the analysis of different materials, including liquid crystals, granular media, and cellular solids.
Cosserat model – It is an advanced continuum mechanics framework where each material point acts as a rigid particle with six independent degrees of freedom, three for translation and three for rotation. This theory expands on classical physics to account for internal micro-structures and rotational effects which standard point-particle models ignore.
Cosserat theory – It is an extension of standard continuum mechanics in which each material point is treated as a rigid particle with six degrees of freedom, including three for translation and three for independent rotational movements. This approach allows for a more realistic representation of complex materials and deformation processes, particularly in microstructured brittle materials and fault zones.
Cost – It is the value of scarce economic resources (such as money, labour, materials, equipment, and time) consumed to design, manufacture, build, operate, or maintain a product, system, or project.
Cost allocation – In design, it is the process by which the components of a design are assigned a target cost.
Cost analysis – It is a systematic method used to identify, quantify, and forecast all direct and indirect expenses tied to a project, product, or design choice.
Costate equation – It is a first-order differential equation in optimal control theory which describes how costate variables (or adjoint variables) evolve over time. It is formally defined as ‘lambda(t) = dh/dx’, where ‘lambda(t)’ is the vector of costate variables (also called adjoint or multiplier variables), ‘H’ is the Hamiltonian function of the optimal control system, and ‘x(t)’ is the vector of system state variables.
Costate variable – It is a mathematical variable which measures the sensitivity or ‘shadow price’ of an optimization objective (such as minimizing fuel or time) with respect to a change in a system’s state variable.
Cost automation – It refers to the use of software, algorithms, data models, and digital tools to calculate, track, and optimize financial expenses, such as material use, labour, tooling, and life-cycle costs, with little to no manual intervention.
Cost behaviour – Costs are classified according to their behaviour in relation to change in relation to production volume within given period of time. As per cost behaviour, cost elements normally fall into two categories. These are variable costs and fixed costs. Fixed costs and variable costs comprise total cost. Fixed costs are those costs which are always present in the production and which do not have variations. These costs do not vary with production, do not change regardless of the type of service or the same schedule. Fixed Costs remain fixed irrespective of changes in the production volume in given period of time. These costs remain the same throughout the period of the work. Variable costs are characterized as those costs which vary with the volume of the production or the performed activity. The variable costs increase as the production increases and decrease when the production decreases. These costs are directly proportional to process activities in a given period. An example of variable cost in a process is the raw material cost. These costs differ from fixed costs which tend to remain the same regardless of production output. Variable costs change according to volume of production.
Cost benefit analysis – It is a tool which is used for the determination of the worth of a project, programme or policy. It is a systematic approach to estimating the strengths and weaknesses of alternatives which satisfy transactions, activities or functional requirements for the organization. It is a technique which is used to determine options that provide the best approach for the adoption and practice in terms of benefits in labour, time and cost savings etc. The cost benefit analysis is also defined as a systematic process for calculating and comparing benefits and costs of a project or decision. Broadly, cost benefit analysis has two purposes namely (i) to determine if it is a sound investment / decision (justification / feasibility), and (ii) to provide a basis for comparing projects. It involves comparing the total expected cost of each option against the total expected benefits, to see whether the benefits outweigh the costs, and by how much. In cost benefit analysis, benefits and costs are expressed in monetary terms, and are adjusted for the time value of the money, , so that all flows of benefits and flows of project costs over time (which tend to occur at different points in time) are expressed on a common basis in terms of their net present value. cost benefit analysis is frequently used to appraise the desirability of a given policy. It is an analysis of the expected balance of benefits and costs, including an account of foregone alternatives and the status quo. Cost benefit analysis helps predict whether the benefits of a policy outweigh its costs, and by how much relative to other alternatives (i.e. one can rank alternate policies in terms of the cost benefit ratio). In cost benefit analysis, both the tangible and intangible costs as well as tangible and intangible benefits are considered.
Cost-benefit analysis (CBA) framework – It is a systematic, data-driven methodology used to evaluate whether the economic and operational benefits of an engineering project, design, or infrastructure choice outweigh its total costs.
Cost-benefit assessment – It is a systematic, data-driven framework used to evaluate the economic and social viability of a project, design, or infrastructure system. It compares all expected positive outcomes (benefits) against all expected negative impacts (costs) over a specific time-frame.
Cost breakdown analysis – It refers to the process of identifying the factors that determine the price of a product. It essentially pinpoints all the elements within a product’s price, resulting in what the product costs. A cost breakdown analysis is a four-step process comprising data collection, systematic expansion of the cost elements, determination of the cost drivers and the development of insights. This analysis is critical to supplier development since the knowledge gathered during the process enables organizations to identify a supplier’s strengths and weaknesses.
Cost breakdown structure – It is a hierarchical framework which divides a project’s total costs into manageable, logical categories and sub-categories.
Cost control – It is a managerial effort to attain cost goals within a particular environment. Cost control is not a specific programme. Rather, it is a routine activity which is carried out continuously. Cost is required to be controlled; otherwise, there are wastages and misappropriation. Cost control is an important activity for any efficient organization since it has a major impact on the profitability of the organization. Cost control can be broken into four functions namely cost estimation, production monitoring, cost calculation and evaluation, and cost modeling.
Cost driver – It is a factor which causes a change in the cost of an activity or product. Identifying and understanding cost drivers is necessary for accurate costing, pricing, and profitability analysis, since they directly influence the allocation of costs to products or services. Cost drivers can range from production volume, material costs, and labor hours to machine usage and operational complexity. In manufacturing, recognizing key cost drivers helps optimize resources and control expenses.
Cost driver analysis – Cost driver analysis identifies activities which influence the cost and performance of subsequent activities. By reducing or eliminating the event which triggers the first activity in the chain, it can eliminate the need for all subsequent the activities. For example, the detection of a defective part needs the part to be reworked or scrapped, the cause of the defect to be corrected, the problem documented, and other related activities. By eliminating the cause i.e., the defective part, the need to perform all subsequent activities is eliminated since they are executed only when a defective part occurs. Costs are hence reduced. By identifying the cost drivers of an organizational process or an activity, the organization can control costs most effectively.
Cost-effectiveness – It is the practice of maximizing a design’s performance and value while minimizing total expenditures over its entire life-cycle. Cost-effectiveness compares the financial and operational benefits of a solution against its total costs to ensure it meets requirements without wasting money.
Cost efficiency – It is the practice of delivering a project, product, or system for the lowest possible cost while strictly maintaining required quality, safety, and performance standards.
Cost, engineering – Engineering costs refer to the expenses associated with detailed design and engineering services necessary for project execution, including design engineering, procurement, construction supervision, and administrative charges. These costs vary based on project scope and are typically estimated individually, considering factors such as project size and client-contractor relationships.
Cost estimate – It is the calculated prediction of all future resources, labour, materials, and overhead costs needed to complete a project based on a defined scope and specific point in time.
Cost function – It is a mathematical expression which measures system error, operational expense, or performance deviation to guide optimization.
Cost management – It is normally considered as a set of techniques and methods for controlling and improving the organizational activities, processes, products, and services, as well as to achieve cost effectiveness (cost reduction, value improvement, and substitution) by collecting, analyzing, evaluating, and reporting cost information for budgeting, estimating, forecasting, and monitoring costs, in order to assist decision making process of the management.
Cost management system – The objectives of cost management system are (i) accurate product / service costs, (ii) assessing product and service profitability, (iii) understanding internal processes and activities, (iv) controlling costs, and (v) assisting in achieving strategies such as strategic plan, and value chain. There is not one cost management system which exists. Costs important to one organization can be irrelevant to another organization. Similarly, costs which are important in one context to the organization are unimportant in other contexts. An understanding of the structure of the market environment in which the organization operates is an important input in designing a cost management system.
Cost of electricity production – It is the total expense incurred to build, operate, and maintain a power plant divided by the total electrical energy it generates over its lifetime, typically measured in currency per kilowatt-hour or megawatt-hour.
Cost of quality – The cost associated with ensuring product quality. This cost can mean the difference between unacceptable and acceptable product results.
Cost-plus contract – It is an agreement where the project owner reimburses the engineering firm or contractor for all actual, documented expenses incurred, such as labour, materials, and equipment—plus an additional fee to cover profit and overhead.
Cost price – It is the price which covers all costs involved in producing a product, ensuring that no loss is incurred. It serves as the baseline for determining the selling price.
Cost-push inflation – It is a form of inflation caused by an increase in the cost of production inputs, such as raw materials and wagers, which leads to an increase in prices.
Cost reduction – It is the process used by an organization aiming to reduce its costs and increase its profits, or to accommodate reduced income. Depending on the organization and its products and services, the strategies can vary.
Cost recovery method – This method of revenue recognition is a concept in accounting which refers to a method in which an organization does not recognize profit related to a sale until the cash collected exceeds the cost of the good or service sold.
Cost-reimbursable contract – It is an agreement where the project owner pays the contractor for all actual expenses incurred during the work, plus an additional fee for profit.
Costs – It is related to the economic resources necessary to accomplish work activities or to produce work outputs. Normally, costs are expressed in terms of units of currency. Hence, costs are the amount of money representing the resources spent for the production of output.
Costs as per the cost functions – There are different functions for which normally the cost is determined. For example, these are production cost, administration cost, marketing cost, and research and development (R & D) cost etc.
Co-surfactant – It is a secondary amphiphilic molecule added alongside a main surfactant in chemical and process engineering to further reduce interfacial tension, increase interfacial fluidity, and stabilize micro- or nano-emulsions.
Cotter – It is a flat, tapered wedge or pin driven transversely through a slot or hole in coaxial parts to lock them tightly together and handle axial forces.
Cotter pin – It is a two-pronged metal fastener inserted through a drilled hole in a bolt or shaft and bent outward to lock other components, like castle nuts or clevis pins, safely in place. It is a pin or wedge passing through a hole to fix parts tightly together.
Cottrell process – It is the process for the removal of solid particulates from gases with electro-static precipitation.
Couette flow – It is the flow of a viscous fluid in the space between two surfaces, where one surface moves tangentially at a constant velocity relative to the other. It is a steady, incompressible, and laminar shear-driven flow where motion is generated by the viscous drag of the moving boundary.
Couette flow model – It describes the steady, laminar motion of a viscous fluid trapped between two parallel plates (or surfaces), where one surface moves tangentially at a constant velocity relative to the other.
Couette viscometer – It is a rotational instrument used to measure the absolute viscosity of a fluid by placing it between two coaxial (concentric) cylinders and measuring the transmitted torque.
Coulisse – It is a type of gate valve using runners or slides as a guiding mechanism operating in high temperature applications i.e. +300 deg C.
Coulomb – It is the quantity of electricity which is transmitted through an electric circuit in 1 second when the current in the circuit is 1 ampere. It is the quantity of electricity which deposits 0.001118 grams of silver.
Coulomb attraction – It is also called Coulombic attraction. It is the electrostatic force of attraction pulling together two oppositely charged particles or objects.
Coulomb barrier – It is the electrostatic repulsion force barrier between two positively charged atomic nuclei which they are to overcome or tunnel through to get close enough for the strong nuclear force to bind them together.
Coulomb blockade – It refers to the phenomenon where the addition of an electron to a small conductive dot is inhibited because of the electrostatic repulsion (Coulomb charging energy) when the energy exceeds the thermal energy, needing external gate bias to allow tunneling. This effect is fundamental in the operation of single-electron devices.
Coulomb collision – It is a binary, elastic interaction between two charged particles (such as electrons or ions) which interact through their long-range electric fields as per the Coulomb’s law.
Coulomb constant – It is a proportionality factor in Coulomb’s law which relates electric force to charge and distance, with a value of 8.98755 × 10 to the power 9. Its SI (International System of Units) unit is Newton meter squared per coulomb squared.
Coulomb counting – It is a technique used to estimate the ‘state of charge’ (SoC) or remaining capacity, of a battery. It works by measuring the electric current flowing into or out of a battery and integrating (adding or subtracting) that current over time to calculate the total charge transferred.
Coulomb criterion – It is frequently expanded as the Mohr-Coulomb criterion. It is a mechanical failure model which defines the shear strength of a material as a linear function of the normal stress acting on the failure plane.
Coulomb efficiency – It is also called coulombic efficiency or Faradaic efficiency. It is the ratio of the electrical charge extracted from a battery or electro-chemical cell during discharge to the charge inserted into it during charging. ‘Coulomb efficiency = (discharge capacity/charge capacity) x 100 %’.
Coulomb explosion – It is the rapid, destructive fragmentation of a molecule, crystal lattice, nano-particle, or liquid droplet caused by mutual electrostatic (Coulomb) repulsion when an intense loss of electrons leaves behind an excess of localized positive charges. When the repulsive forces between positively charged ions exceed the cohesive binding energy or surface tension holding the material together, the structure violently shatters and ejects high-energy ions and electrons.
Coulomb force – It is the pull or push between two charged particles that are not moving. It is the attractive or repulsive electrostatic force exerted by stationary electrically-charged objects on each other.
Coulomb friction – It is a term used to indicate that the frictional force is proportional to the normal load. It refers to the component of force exerted between two objects in contact which are moving relative to each other. It has a fixed value at all non-zero speeds and acts opposite to the direction of sliding, contributing to slowing down the motion.
Coulombic force – It is a force between charged particles such as ions. The force is attractive when the particles are of opposite charge.
Coulomb gap – It is a soft depletion or reduction in the single-particle density of states (DOS) near the Fermi level in disordered or localized electronic systems (such as amorphous or doped semi-conductors and Coulomb glasses) caused by long-range electron-electron Coulomb interactions.
Coulomb interaction – It is the electrostatic attraction or repulsion force which occurs between electrically charged particles, as defined by Coulomb’s law.
Coulomb model – It is a friction model stating that the force of friction is proportional to the normal load and independent of the contact area, characterized by Coulomb’s coefficient of friction, which includes static and kinetic coefficients. This model is noted for its simplicity and is frequently used in manufacturing processes.
Coulomb model of friction – It states which force of dry friction (F) between two contacting surfaces is directly proportional to the normal contact force (N) and is independent of the apparent contact area. Key equation is ‘F = M x N’, where ‘F’ is frictional force magnitude (or maximum static friction). ‘M’ is dimensionless coefficient of friction (static Ms or kinetic Mk), ‘N’ is normal force pressing the two surfaces together
Coulomb-Mohr fracture criterion – It is a theory of fracture based on experimental values for both tensile and compressive strength in which fracture on a plane is hypothesized to occur when a critical combination of normal stress and shear stress occur on the plane (maximum pressure reduced shear stress). The critical combination of stresses is assumed to be a linear relationship given by the equation |T| + mu.S = Ti (uniaxial load) where ‘T’ and ‘S’ are shear stress and normal stress, respectively, and ‘mu’ and ‘Ti’ are material constants.
Coulomb repulsion – It is the electrostatic force which pushes two like-electric charges (two positive charges or two negative charges) away from each other.
Coulomb’s law – It is a law which describes the quantity of force between two electrically charged particles at rest. It defines the electrostatic force of attraction or repulsion between two stationary, charged point objects. It states that the magnitude, or absolute value, of the attractive or repulsive electro-static force between two point-charges, is directly proportional to the product of the magnitudes of their charges and inversely proportional to the square of the distance between them. Coulomb discovered that bodies with like electrical charges repel and opposite charges attract, with the force acting along the straight line joining the two point charges.
Coulomb’s law of friction – It states that the maximum static or kinetic friction force between two dry solid surfaces is directly proportional to the normal force pressing the surfaces together. Coulomb’s two laws of friction state that (i) friction force is proportional to normal force, and (ii) friction force is independent of the size of the contact area.
Coulomb type – It refers to a class of interatomic potentials characterized by a repulsive force which follows a screened Coulombic relationship,
Coulometer – It is an electrolytic cell arranged to measure the quantity of electricity by the chemical action produced in accordance with Faraday’s law.
Coulometry – It is an electrochemical technique in which the total number of coulombs consumed in an electrolysis is used for determining the quantity of substance electrolyzed.
Coulter – It refers to a method for measuring particle size and counting particles in a solution, based on changes in electrical resistance as particles pass through a micro-channel, resulting in potential pulses that correlate with particle size distribution.
Coulter counter analysis – This method of evaluating steel cleanliness is similar to liquid metal cleanliness analyzer (LIMCA). It can be used to measure the size distribution of inclusions extracted by slime and suspended in water (inclusions larger than sub-micron).
Coumarone – It is also known as benzofuran. It is a colourless, sweet-smelling, oily liquid with the molecular formula C8H6O. It is a heterocyclic compound composed of a fused benzene and furan ring, making it a key structural unit in several biologically active compounds and synthetic materials.
Count – It consists of measuring and monitoring the number of ionizing radiation particles present using radiation detection equipment.
Countable set – It is a set for which there exists an injective map from the set into the natural numbers, allowing each element to be uniquely associated with an integer.
Countdown timer – It is a digital, mechanical, or software-based mechanism which decrements a pre-set time interval down to zero, triggering an action, interrupt, or signal upon completion.
Counter – It is a sequential logic circuit which stores and updates a count of how many times an event or clock pulse occurs.
Counter-blow equipment it is the equipment with two opposed rams which are activated simultaneously to strike repeated blows on the work-piece placed midway between them.
Counter-blow hammer – It is a forging hammer in which both the ram and the anvil are driven simultaneously toward each other by air or steam pistons.
Counter-boring – It is the removal of material to enlarge a hole for part of its depth with a rotary, pilot guided, end cutting tool having two or more cutting lips and normally having straight or helical flutes for the passage of chips and the admission of a cutting fluid.
Counter circuit – It is a sequential circuit which counts clock pulses and stores the count in memory elements, such as flip-flops. It can be classified as either synchronous, where all flip-flops are clocked simultaneously, or asynchronous, where each flip-flop is clocked at different times based on propagation delays.
Counter-current – it refers to a flow arrangement where two fluids move parallel to each other in opposite directions, resulting in higher efficiency and reduced heat transfer surface area compared to co-current flow systems.
Counter-current chromatography – It is a liquid–liquid partition chromatographic method which utilizes an empty column filled with a liquid stationary phase, allowing for a large sample loading capacity and predictable separations based on solute partitioning.
Counter-current cooling tower – It is an industrial heat rejection device where heated process water flows vertically downward by gravity while cool ambient air is drawn vertically upward through the same fill media in the opposite direction (180-degree).
Counter-current conveyor – It is a conveyor system with material flow direction opposing the conveyor belt’s movement, needing checks for proper alignment and effective material control.
Counter current exchange – It is a mechanism between two flowing bodies flowing in opposite directions to each other, in which there is a transfer of some property, normally heat or some chemical. The flowing bodies can be liquids, gases, or even solid powders, or any combination of these.
Counter current flow – It is an arrangement where two fluid streams move parallel to each other in opposite directions to maximize the transfer of heat, mass, or chemical properties.
Counter-current operation – It is a flow arrangement where two streams (fluids, gases, or slurries) move parallel to each other in opposite directions.
Counter current reactor – It is a chemical or thermal engineering system where two working phases or fluid streams move in opposite directions to each other.
Counter electrode – In emission spectroscopy, it is the electrode which is used opposite to the self-electrode or supporting electrode and which is not composed of the sample to be analyzed. In voltammetry, it is the current between the working electrode and counter electrodes is measured.
Counter-face – It is the opposing surface or material which physically rubs, slides, or interacts against a main component. It is the surface or material which interacts with another surface during sliding, characterized by its surface texture, roughness, and material composition, which influence the development of wear debris and transfer films.
Counter flow – It is a design arrangement where two working fluids move in parallel paths through an apparatus but in opposite directions to each other. This configuration is very frequently used in heat exchangers, cooling towers, and chemical processing units to transfer heat, mass, or momentum between two media.
Counter-flow configuration – It is also known as a counter-current configuration. It is a design arrangement where two working fluids, air-streams, or chemical reactants move in opposite directions parallel to one another.
Counter-flow heat exchanger – It is also called counter-current heat exchanger. It is a device which transfers thermal energy between two fluids moving in opposite directions parallel to one another.
Counter-formal contact – It is also called non-conforming contact. It occurs when two mating surfaces do not geometrically fit snugly together, resulting in a nominal point or line contact. Unlike conformal contacts (where the surfaces curve closely around one another to distribute loads over a wide area, like a journal bearing), counter-formal surfaces curve away from each other or meet at contrasting angles.
Counter-formal surfaces – These are the surfaces whose centres of curvature are on the opposite sides of the interface, as in rolling element bearings or gear teeth. In wear testing, this term is sometimes used to indicate that the test sample surfaces are not conformal (e.g., with a sphere-on-flat or flat block-on rotating ring configuration). In such cases, the nominal contact area of at least one of the test piece surfaces increases as the quantity of wear increases.
Counter-gravity casting – It is a manufacturing process where molten metal is pushed or drawn upward into a mould against the force of gravity using a vacuum or low-pressure gas.
Counter-gravity filling – It is a manufacturing process where liquid metal moves upward into a mould against the force of gravity using a vacuum or gas pressure.
Counter-ion – It is an ion which pairs with an oppositely charged ion to keep an overall electrical neutrality in a chemical substance or solution.
Counter-ion concentration – It refers to the local or bulk number of mobile, oppositely charged ions (counter-ions) present in a system, such as a colloid, poly-electrolyte solution, ion-exchange membrane, or electrical double layer, to balance the fixed or main charges.
Counter-ion distribution – It refers to the spatial arrangement and concentration profile of mobile ions (counter-ions) surrounding a charged surface, particle, or polymer in a solution. It describes how oppositely charged ions cluster near or spread out away from a fixed surface charge to maintain local and overall electrical neutrality.
Counter-lock – It is a jog in the mating surfaces of dies for preventing the lateral die shift caused by side thrust during the forging of irregularly shaped pieces.
Counter-locked dies – It is referred to as dies featuring a counter-lock. These are custom-machined forging or stamping tools designed with interlocking steps, matching angles, or matching profiles along their parting line. Their main function is to counter-balance and prevent side-thrust. This side force occurs when compressing asymmetrical shapes or inclined planes, causing the upper and lower halves of the die to slide apart or misalign.
Counter-measure – It is an action, device, or system designed to reduce, block, or offset the negative impact of a threat, vulnerability, or failure.
Counter mode – It is a block cipher mode of operation which turns a traditional block cipher into a high-performance stream cipher by encrypting a sequential counter value rather than the plaintext itself.
Counter pressure casting – It is an advanced metal casting method where both the melting furnace and the mould cavity are enclosed in separate, pressurized chambers. By creating a precise pressure difference between the two chambers, liquid metal is pushed smoothly upward into the mould, reducing turbulence and gas defects. The counter-pressure allows the regulation of the filling speed of the metal into the mould, independently from the pressure on the molten bath in the furnace.
Counter-rotating – It consists of conveyors with opposing rotational directions, necessitating regular alignment checks and maintenance to prevent interference.
Counter-sinking – It is beveling or tapering the work material around the periphery of a hole creating a concentric surface at an angle less than 90-degree with the centre line of the hole for the purpose of chamfering holes or recessing screw and rivet heads.
Counter-sunk hole – It is a conical enlargement at the opening of a standard cylindrical drilled hole which allows a flat-head screw, bolt, or rivet head to sit flush with or below the surrounding material surface.
Counter surface – It is also called a counter-face or mating surface. It refers to the second, opposing surface which physically contacts and slides, rolls, or seals against a main component.
Counter-weight – It is a weight which is used to balance the load on the conveyor belt, needing periodic adjustments to ensure consistent and proper tension.
Counter-weight take-up – It is a tensioning device utilizing a counter-weight to maintain proper belt tension, necessitating periodic adjustments for optimal performance.
Counting circuit – It is a sequential circuit that consists of memory elements, such as flip-flops, used to count clock pulses and store the received counts. It can be categorized as either synchronous, where all flip-flops are clocked simultaneously, or asynchronous, where only the least significant stage is clocked first, influencing the timing of subsequent stages.
Count rate meter – It is an electronic device which measures and displays the average number of radiation pulses or electrical signals received per unit of time from a detector. It converts incoming random particle events into a continuous, readable meter value or voltage.
Country rock – It is loosely used to describe the general mass of rock adjacent to an orebody. It is also known as the host rock.
Couple – It is a system of two parallel forces which are equal in magnitude, opposite in direction, and do not share the same line of action. In galvanic corrosion, it is a pair of dissimilar conductors, normally metals, in electrical contact.
Coupled analysis – It is an analytical or numerical method that studies how two or more distinct physical phenomena interact and influence one another within a system. It is the integration of multiple physical phenomena, such as thermal, mechanical, and electro-magnetic interactions, to study the behaviour of materials and structures under realistic conditions. This method is particularly important for understanding the interactions and performance of polymeric materials in environments where they are in contact with other materials or subjected to various loading conditions.
Coupled antenna – It refers to an antenna which is electro-magnetically linked to another nearby antenna or conductive object, where the energy radiated or received by one element induces currents and alters the performance of the other.
Coupled circuits – These two or more electrical circuits connected such that energy, electric charge, or signals can transfer from one circuit to another.
Coupled collector – It is a solar water heating set-up where the solar collector panel (absorber) and the water storage tank are physically separated but linked through a network of pipes.
Coupled device – It normally refers to a component or circuit where energy, signals, or physical states are transferred from one part to another.
Coupled domain – It is frequently referred to as coupled fields; It refers to a system where two or more distinct physical domains interact with each other, meaning the behaviour of one domain directly influences and changes the behaviour of the other. In a single-domain system, people analyze one type of physics in isolation (e.g., just fluid flow or just structural stress). In a coupled domain, the governing differential equations of the different physical phenomena are linked and are to be solved simultaneously or iteratively since their boundary conditions, material properties, or source terms depend on one another.
Coupled equation – It is a mathematical expression or a system of equations where multiple unknown variables or physical quantities are mutually dependent, meaning people cannot solve each equation completely on its own.
Coupled Eulerian–Lagrangian (CEL) method – It is a computational simulation approach which merges two distinct reference frames, Lagrangian (where the mesh moves and deforms with the material) and Eulerian (where the mesh stays fixed in space while material flows through it).
Coupled-field analysis – It is a method that studies how two or more distinct physical phenomena interact with and influence each other within a single system. Instead of analyzing each physical effect separately (such as running a heat test first and a stress test second without mutual feedback), a coupled-field approach solves the governing equations simultaneously or iteratively. Changes in one field (e.g., rising temperature) actively update the properties, loads, or boundary conditions of another field (e.g., structural expansion or stress).
Coupled fluid flow – It is a physical process where fluid movement and another systemic behaviour (such as solid rock / soil deformation, thermal energy transfer, or structural mechanics) interact dynamically, meaning changes in one directly influence and alter the other in real time.
Coupled load – It refers to two equal, parallel forces acting in opposite directions on a structure or beam, which produce a pure rotational or twisting effect (moment) without any net linear force.
Coupled model – It is a model which combines components, which can be either atomic or other coupled models, to simulate complex systems, allowing for interactions between the components.
Coupled modelling – It is the technique of linking two or more distinct computational or mathematical models so they can share data and simulate feedback interactions within a complex system.
Coupled oscillator model – It is a system of two or more individual oscillators (such as mass-spring systems, LC (inductor-capacitor) circuits, or phase-locked loops) connected so that energy, force, or phase signals can exchange between them.
Coupled port – It is a dedicated auxiliary port on a passive device, most notably a directional coupler, which delivers a fixed, precisely known fraction of the signal power traveling through the main transmission line. It allows engineers to sample, monitor, or manipulate a traveling wave without disrupting the primary signal path.
Coupled problem – It occurs when two or more distinct physical phenomena, system variables, or numerical equations interact such that the solution of one directly influences and depends on the other.
Coupled solution – It refers to an analytical or numerical approach where two or more distinct physical systems, equations, or modules interact and are to be solved simultaneously since the outcome of one directly influences the other.
Coupled system – It is a collection of two or more distinct components, modules, or physical phenomena which interact with and influence each other, where the state or behaviour of one directly affects the others.
Coupled transducer – It is very frequently referred to as an air-coupled transducer or a fluid-coupled/contact transducer. It is a specialized device which transmits or receives energy, typically ultrasonic or acoustic waves, across a physical boundary or medium without needing a rigid mechanical bond, or by using a specific coupling layer to match acoustic impedances.
Coupler – It is a device used to connect two things, parts, systems, or pieces of equipment together. Common types of couplers are mechanical couplers which connect two rotating shafts together to transfer power from a motor to a machine, pipe and plumbing couplers which are short pipe fittings used to join, extend, or repair two pipes, railway couplers which are heavy mechanisms on the ends of rail cars which connect them into a single train, and electronic couplers which are parts like optocouplers or acoustic couplers which pass electrical or sound signals between isolated circuits.
Coupler mirror – It is very frequently referred to as an output coupler mirror. It is a partially reflective and semi-transparent mirror used in a laser resonator to extract a controlled portion of the circulating light as a useful laser beam. While a standard mirror aims for nearly 100 % reflection, a coupler mirror is engineered with a specific, calibrated balance of reflectivity (R) and transmissivity (T).
Coupling – It is a mechanical element part that connects two shafts together to accurately transmit the power from the drive side to the driven side while absorbing the mounting error (misalignment) etc. In case of pipe fitting, a coupling connects two pipes to each other. If the size of the pipe is not the same, the fitting can be called a reducing coupling or reducer, or an adapter. By convention, the term ‘expander’ is not normally used for a coupling which increases pipe size, instead the term ‘reducer’ is used. In rolling mills, couplings serve for transfer of torque of the driving train to the work rolls. Their function consists in absorbing roll force impacts (shocks) and prevention of the transfer these shocks to the electric motor. The common types of coupling used in the rolling mills are cardan shaft coupling, gear coupling, and universal coupling.
Coupling agent – It is a chemical substance which is designed to react with both the reinforcement and matrix phases of a composite material to form or promote a stronger bond at the interface.
Coupling capacitance – It refers to the capacitive coupling which can occur between signal wires in a measurement circuit and nearby conductors, such as mains-carrying conductors or earth, affecting the noise voltage induced in the system.
Coupling capacitor – It is a passive electronic component connected in series between two circuit stages to pass alternating current (AC) signals while blocking direct current (DC) voltages.
Coupling coefficient – It is a dimensionless number which measures the degree of magnetic or electrical energy transfer between two coupled circuits, inductors, or transformer coils.
Coupling / decoupling network – It is a specialized electronic device used in electro-magnetic compatibility (EMC) testing to inject controlled test signals or electrical disturbances onto a cable while protecting the surrounding equipment and preventing the disturbances from leaking back into the power supply or support equipment.
Coupling effect – It refers to a phenomenon where an action, process, or physical property in one part of a system directly influences or is influenced by another part.
Coupling equation – It is a mathematical expression which defines how two or more distinct physical systems, variables, or differential equations interact and influence one another.
Coupling guard – It is a protective cover or enclosure fitted around a shaft coupling which joins a driving machine (such as an electric motor) to a driven machine (such as a pump or compressor).
Coupling hub – It is the machined end-piece or component of a mechanical coupling which mounts directly onto a rotating shaft to transmit torque and rotational power.
Coupling loss – It is the energy or signal power lost when energy is transferred from one circuit, device, medium, or structural sub-system to another. It is typically measured in decibels (dB) or watts.
Coupling material – Itis a hydraulic substance used to ensure full contact between a transducer and a test surface, facilitating the transfer of sound waves during testing. Common examples include water, oil, grease, glycerin, and cellulose gum powder, with cellulose gum being preferred for its cost-effectiveness and beneficial properties for testing.
Coupling matrix – It is a mathematical array (n × n) which describes the electrical, mechanical, or physical interactions and connection strengths between the components of an interconnected system.
Coupling network – It is an arrangement of components designed to transfer energy or signals from one circuit, stage, or medium to another while managing frequency response, impedance matching, and isolation. In electro-magnetic compatibility (EMC) testing, a coupling / decoupling network (CDN) is a specific device used to inject test signals or radio-frequency (RF) noise directly into a cable or line to test immunity, while preventing those disturbances from leaking back into the power supply or support equipment.
Coupling path – It is the physical route or mechanism by which energy (frequently unwanted interference or a signal) travels from a noise source to a susceptible victim circuit or component.
Coupling photo-catalysis – It refers to the integration of a light-driven catalytic process with another treatment method, physical field, or reaction mechanism to overcome performance limits and boost overall efficiency.
Coupling ratio – It refers to the proportion at which input optical signals are divided between the output ports of an optical coupler, such as a 50:50 ratio in a 1×2 coupler, indicating that half of the input optical power is coupled to each port. It also quantifies the magnetic or inductive coupling degree (k) between two coils, representing how much magnetic flux from a transmitter coil links to a receiver coil (ranging from 0 for independent coils to 1 for tight, ideal coupling). In coupled shear wall or steel plate shear wall systems, it measures the percentage of total overturning or seismic moment resisted by the coupling beams against the entire wall system.
Coupling, shaft – Shaft coupling is a mechanical feature which connects two shafts to transfer torque while accommodating misalignment, hence improving stability and reducing issues such as vibration and irregular bearing wear. It serves four main purposes namely power transmission, joining misaligned shafts, reducing shock and friction, and facilitating assembly and disengagement.
Coupling spacer – It is an intermediate length of shaft or centre piece installed between two coupling hubs or rotating shafts in a power transmission system.
Coupling strength – It refers to the degree of interaction, energy exchange, or inter-dependence between two or more connected systems, components, or modules.
Coupling transformer – It is a magnetic transformer used to transfer alternating current (AC) signals or power from one circuit to another while providing impedance matching and direct current (DC) isolation.
Coupon – It is a small, representative sample of a material or component used for testing, analysis, and quality control without damaging the actual structure. It is a piece of metal from which a test sample is to be prepared. It is frequently an extra piece (as on a casting or forging) or a separate piece made for test purposes (such as a test weldment).
Coupon level -It refers to a type of testing which utilizes established coupon data to assess material properties such as stiffness and strength, benefiting all design areas fabricated from the material of interest. It serves as a foundational analysis method which informs more complex testing for specific components or structures.
Coupon, test – Test coupons are metal samples inserted into streams for monitoring corrosion in plant equipment and pipelines, used to evaluate materials, coatings, and inhibitors through long-term averaging techniques. These coupons need careful sample preparation and are subjected to periodic removal and assessment for weight loss or depth of penetration due to corrosion.
Courant number – It is also known as the CFL number or Courant–Friedrichs–Lewy number. It is a dimensionless quantity which measures how far information or physical properties (such as a fluid wave or flow) travel across a discrete grid cell during a single time step.
Course – It is a horizontal layer or row of bricks in a structure. Courses consist of alternate layers of material in a pattern, or brickwork.
Course of action – It is a planned and structured sequence of steps or risk-response measures designed to solve a specific technical problem, system failure, or project risk.
Course structure – It is the organization and content of an educational / training programme, which can reflect the biases of educators / trainer and available expertise, potentially leading to a mismatch between the skills needed for employment and those acquired by students/ workers. It emphasizes the importance of balancing theoretical and practical inputs, including hands-on training in laboratory settings.
Covalency – It is the number of electron pairs which an atom shares with other atoms to form covalent bonds. It also describes the degree of orbital mixing and electron-sharing character within chemical bonds (such as in metal-ligand complexes, ceramics, and semi-conductors), which directly influences material hardness, polarizability, and reactivity.
Covalent – It refers to a type of chemical bond between two atoms or ions where electron pairs are shared, allowing each atom to achieve a stable outer electron shell. Covalent bonds can be categorized as polar or non-polar, depending on the electro-negativity of the atoms involved.
Covalent attachment – It is the process of permanently binding molecules, biomolecules, or functional groups to a material surface or another molecule through stable chemical covalent bonds.
Covalent bond – It is a main bond arising from the reduction in energy associated with overlapping half-filled orbitals of two atoms. Covalent bonds are chemical links between two atoms or ions in which electron pairs are shared, allowing each atom to achieve a stable outer electron shell. These bonds can be categorized into polar and nonpolar types based on the electronegativity of the participating atoms.
Covalent contribution – It refers to the portion of a chemical bond’s character or bonding interaction which arises from the sharing of electron pairs through the spatial overlap of atomic orbitals, rather than purely electro-static or ionic attraction.
Covalent immobilization – It is the chemical process of permanently and irreversibly binding biomolecules to a solid support material or matrix through strong covalent bonds.
Covalent organic frame-works – These are 2D or 3D porous and crystalline organic structures where building blocks are linked by strong covalent bonds, composed entirely of light elements such as hydrogen, boron, carbon, nitrogen, and oxygen. Covalent organic frameworks (COFs) are defined by their ability to undergo rational, and molecular-level predesign. Unlike traditional amorphous polymers, Covalent organic framework engineering relies on reversible covalent bond formation. This reversibility allows the building blocks to self-correct errors and to rearrange during assembly, resulting in highly ordered, periodic two-dimensional (2D) or three-dimensional (3D) crystalline structures.
Covalent radius – It is a measure of an atom’s effective size when forming a covalent bond, defined as half the distance between the nuclei of two identical, bonded atoms. It is used to predict inter-atomic bond lengths and construct molecular bond graphs.
Covariance – It is a statistical measure which quantifies the direction of the linear relationship between two random variables. It tracks how much the variables change together, indicating whether they move in the same or opposite directions.
Covariance analysis – It is frequently referred to as analysis of covariance (ANCOVA. It is a statistical technique which blends analysis of variance (ANOVA) with regression analysis to evaluate the relationship between a dependent (response) variable and one or more categorical and continuous variables.
Covariance determinant – The determinant of a covariance matrix (frequently called the generalized variance) measures the overall dispersion or spread of a multi-dimensional probability distribution or dataset.
Covariance function – It is a mathematical tool in probability which measures the joint variability, interdependence, or statistical similarity between two points (‘x’ and ‘y’) in a random field, stochastic process, or time series.
Covariance matrix – It is a square, symmetric matrix which describes the variance of individual variables along its main diagonal and the linear dependence (covariance) between pairs of different variables in its off-diagonal positions.
Covariance terms – These terms refer to the mathematical measures which indicate the co-movement of excess returns between two stocks, calculated to assess how these returns deviate from their respective averages. These terms can reflect both positive and negative relationships in price trends despite the directional movement of the stocks.
Covector – It is defined as an element of the dual space of the tangent space at a point on a manifold. It is also referred to as a cotangent vector, which forms the cotangent space at that point.
Covellite – It is a deep blue copper sulphide mineral with chemical formula CuS.
Cover – It is the outer rubber or polyvinyl chloride (PVC) component of a belt. It protects the belt carcass and provides drive friction. There are cover grades for a broad variety of applications. A cover normally consists of a principal polymer and assorted modifiers, carbon black, antioxidants, accelerators, fillers, plasticizers etc.
Coverage – It is a quantitative metric which measures how thoroughly a system, its code, or its requirements have been exercised and validated by a test suite.
Cover cell – It refers to the top structural and safety assembly of a sealed electro-chemical cell or battery (such as nickel-cadmium or cylindrical lithium-ion cells). In VLSI (very large scale integration) and chip design, a cover cell is a physical-only macro fixed directly to the floorplan which cannot be moved or modified once placed.
Cover coat – It is a porcelain enamel finish applied to and then fused over a ground coat or applied directly to the metal substrate and then fused.
Cover concrete – It is the concrete layer which protects steel reinforcement from corrosion by preventing the ingress of chlorides and carbon di-oxide, achieved through a low water / cement ratio and adequate thickness.
Cover core – It is a core set in place during the ramming of a mould to cover and complete a cavity partly formed by the withdrawal of a loose part of the pattern. It is also used to form part or all of the cope surface of the mould cavity. Also, it is a core placed over another core for creating a flat parting line.
Covered electrode – It is a composite filler metal electrode consisting of a core of a bare electrode or metal cored electrode to which a covering sufficient to provide a slag layer on the weld metal has been applied. The covering can contain materials providing such functions as shielding from the atmosphere, deoxidation, and arc stabilization and can serve as a source of metallic additions to the weld.
Covered roller – It is a cylindrical metal core encased in an outer protective or functional layer, such as rubber, poly-urethane, silicone, ebonite, or fabric.
Covered wagons – These are railway freight wagons in which those consignments are transported which needs protection from rain etc., such as cement, and fertilizers.
Cover gas system – It is an arrangement which uses an inert gas, very frequently argon or helium, to fill the free space or ‘blanket’ volume above a reactive liquid metal, molten material, or sensitive process zone.
Cover grade – In a conveyor belt, cover grade defines the outer rubber layer’s resistance to wear, heat, oil, or fire. This top and bottom rubber compound protects the inner load-bearing carcass from damage, dictating the belt’s overall life-span and operational safety.
Cover half -It is also called the cover die half or fixed die half. It is the stationary section of a die-casting mould which remains attached to the front, non-moving platen of the casting machine during operation.
Covering area – It is the yield expressed in terms of a given number of square meters per kilogram.
Covering power – It is the ability of a solution to give satisfactory plating at very low current densities, a condition which exists in recesses and pits. This term suggests an ability to cover, but not necessarily to build up, a uniform coating, whereas throwing power suggests the ability to get a coating of uniform thickness on an irregularly shaped object. It is also the degree to which a porcelain enamel coating obscures the underlying surface. It is also the ability of a glaze to uniformly and completely cover the surface of the fired ceramic ware.
Cover material – It is also called covering material. It is a secondary layer, coating, or blanket applied to the surface or substrate of a primary structure, component, or landform to protect it from environmental damage, mechanical wear, or chemical degradation.
Cover sequence – It refers to a cyclic sequence or ordered set of statements designed to cover a specific code space or test scenario.
Cover signal – It is the original multimedia or carrier data (such as audio, image, or video) used to conceal or embed a hidden message.
Cover thickness (- It is normally known as concrete cover or clear cover. It is the distance measured from the outer surface of a structural member (like a concrete slab, beam, or column) to the outer face of the steel reinforcement bars (rebar).
Cowling – It is a removable, streamlined metal or composite housing which encloses an engine. It reduces aerodynamic drag, directs cooling airflow across engine parts, and protects internal components from weather, debris, and damage.
Cowper stove – It is also called hot blast stove. It is a specialized type of direct-fired regenerator used in blast furnaces which can operate under high pressure and high temperature, designed to preheat the air blast and improve combustion efficiency.
Cox–Merz rule – It is an empirical (observation-based) relationship in rheology which states that for several unfilled polymer melts and concentrated polymer solutions, the steady-state shear viscosity equals the magnitude of the complex viscosity when the shear rate and the angular frequency are numerically equal.
Cox regression model – It is also known as proportional hazards model. It is the most commonly used regression model for survival data. The response variable is the log of the hazard function.
CP-steel – It means complex phase (CP) steel. These steels are characterized by a mixed micro-structure, mainly consisting of bainitic components. Because of their fine micro-structure, they show very high strengths with a good cold formability and have good hole expansion values and good bending properties.
Crack – It is a fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement. It is also a line of fracture without complete separation.
Crack advance – It refers to the incremental progression or forward movement of a crack tip through a solid material or structure under applied mechanical, thermal, or environmental loads. It measures how far and fast, a crack extends during a single loading step, cycle, or time interval in fracture mechanics.
Crack appearance – It refers to the visual form, pattern, shape, and width of a break, fissure, or fracture on the surface of a material or structure.
Crack arrest – It refers to the phenomenon where crack propagation is halted, frequently occurring when a crack encounters a stress-shielded area, such as a geometrical stiffener or a compressive residual stress field, or when there is a decrease in loading with increasing crack length. It also refers to the ability of a material to stop the propagation of cracks, which is evaluated through experimental techniques such as compact crack arrest testing (CCA) and can involve static and dynamic assessments of fracture toughness.
Crack arrest temperature – It is the specific temperature above which a rapidly running brittle crack in a material stops (arrest) rather than continue to propagate catastrophically.
Crack bifurcation – It is the splitting of a crack into two paths, or the intersection of a crack with a pre-existing crack.
Crack branching – It is a fracture mechanics phenomenon where a single, fast-moving crack tip splits into two or more distinct paths (bifurcation or forking) instead of continuing along a single straight line.
Crack bridging – It refers to a process where unbroken elements, fibres, or flexible membranes span across the faces of a crack to transfer loads and exert a closing force.
Crack chemistry – It refers to the specific chemical processes, species depletion, and electro-chemical reactions which occur inside and around a material crack tip, influencing phenomena like corrosion fatigue and crack propagation.
Crack closing – It is the physical coming-together of the opposing crack surfaces
Crack closure – It refers to the phenomenon where the surfaces of a crack come into contact during loading, which can influence fatigue crack growth (FCG) behavior. This effect can arise from different mechanisms, such as plasticity-induced closure and roughness-induced closure, particularly in near-threshold regimes.
Crack cluster – It refers to a group of interconnected or spatially correlated cracks within a material (such as concrete, rock, or porous solids) which influence the material’s overall transport properties, structural integrity, and failure behaviour.
Crack configuration – It refers to the geometric arrangement, spatial pattern, and orientation of one or more cracks or crack-like flaws within a material or structural component.
Crack creation – It is also called crack initiation. It is the first stage of structural failure, where microscopic damage or structural defects coalesce to form a macroscopic crack. Crack creation occurs when localized stress exceeds the material’s cohesive strength. It typically happens in three steps namely stress concentration, microstructural damage, and nucleation.
Crack curve – It typically refers to a crack growth resistance curve (R-curve) or a fatigue crack growth curve in fracture mechanics.
Crack data – It refers to the digital information, measurements, images, or numerical parameters used to detect, classify, quantify, and analyze fractures or structural defects in materials and infrastructure.
Crack defect – It is a physical separation, linear discontinuity, or fracture within a material’s structure which lowers its effective cross-sectional area and concentrates stress at its tip.
Crack density – It is a quantitative parameter which measures the frequency, distribution, or extent of cracks within a material or structural component.
Crack depth – It is the vertical distance or penetration extent which fracture, fissure, or micro-crack extends from the surface into the interior of a solid material or structural component (such as concrete, steel, or rock).
Crack detection – It is the process of identifying and localizing cracks in civil structures, utilizing methods such as manual inspection by skilled labour or automated techniques involving image processing and machine learning. This process is important for assessing the condition and safety of infrastructure to prevent degradation and potential disasters.
Crack direction – It is also called crack propagation direction. It defines the spatial orientation and trajectory along which a physical separation or microstructural discontinuity grows through a material under applied loads.
Crack displacement – It refers to the relative movement or separation of the opposite faces of a crack when a structural member is subjected to external loads, stresses, or environmental pressures. It describes how much the crack widens, slides, or tears, and is a fundamental parameter in fracture mechanics and structural integrity assessment.
Cracked ammonia – It is a reducing gas produced by the thermal decomposition of anhydrous ammonia over a catalyst, resulting in a gas of 75 % hydrogen and 25 % nitrogen.
Cracked beam – It is a structural element which contains a fracture, split, or discontinuity affecting its local stiffness, dynamic behaviour, and load-carrying capacity. When internal stress exceeds the material’s strength or when external forces outstrip design limits, the beam develops specific crack patterns.
Cracked body – It is a solid structural or mechanical component which contains a macro-crack or a physical discontinuity (a sharp-tipped void, crack, or internal flaw) which alters its load-bearing capacity and stress distribution.
Crack, edge – Edge crack is a crack which initiates and propagates from the free edge or boundary of a material, component, or structural member.
Crack edge vicinity – It refers to the localized region immediately surrounding the boundary or tip of a crack within a material.
Cracked layer – It very frequently refers to a specific stratum or structural layer (such as in layered composites, laminates, or pavement systems) which contains a physical fracture, discontinuity, or network of cracks altering how stress, displacement, and loads are transferred.
Cracked plate – It is a structural plate element (such as a flat sheet, panel, or shell) which contains a discontinuity or crack and is subjected to external mechanical loads, thermal stresses, or vibrations.
Cracked product – It is a hydro-carbon product created by breaking down large, heavy crude oil molecules into smaller, more valuable fractions using heat and pressure (thermal cracking) or a catalyst (catalytic cracking).
Cracked region – It normally refers to a zone or section of a material, structural member (such as concrete beams, slabs, or rock masses), or geological formation where fracturing, micro-cracking, or structural splitting has occurred because of the applied loads, tensile stresses, or environmental forces.
Crack driving force – It is the measure of energy or stress intensity in a material which pushes an existing crack to grow or propagate. It is the mechanical or thermodynamic energy available at a crack tip which drives the crack forward.
Cracked sample – It is also called cracked specimen. It is a test piece with an intentional or pre-existing fracture used to evaluate material strength, crack growth, fracture toughness, and structural integrity.
Crack extension – It is an increase in crack size. It is denoted as ‘da’. It is the physical increase in the length or size of a pre-existing crack or flaw under the influence of mechanical stress, environmental factors, or cyclical loading. It represents the distance a crack tip travels from its initial position (ao) to its current position (a), mathematically expressed as ‘da = a – ao’.
Crack-extension force – It is the elastic energy per unit of new separation area which is to be made available at the front of an ideal crack in an elastic solid during a virtual increment of forward crack extension.
Crack-extension resistance – It is a measure of the resistance of a material to crack extension, expressed in terms of the stress-intensity factor, the crack-extension force, or values of ‘J’ derived using the J-integral concept.
Crack face displacement – It refers to the movement of the surfaces of a crack in response to applied forces, which can occur in different modes such as tension (Mode I), in-plane shear (Mode II), or out-of-plane shear (Mode III).
Crack flanks -These refer to the surfaces on either side of a crack in a material, where stresses can be influenced by factors such as crack bridging mechanisms, which involve fibres that help reduce stress intensity at the crack tip.
Crack front – It is the boundary or leading-edge line which separates the joined (uncracked) portion of a material from the disjoined (cracked) portion in three-dimensional structures.
Crack geometry – It is the physical shape, size, spatial configuration, and surface representation of a fracture or flaw in a material. It determines how stresses concentrate around the defect and dictates how the crack s under mechanical loads.
Crack growth – It is the process by which an existing micro-crack or material flaw increases in length or size when a component is exposed to mechanical loads, cyclic stresses, or harsh environmental conditions. It is the rate of propagation of a crack through a material because of a static or dynamic applied load.
Crack growth behaviour – It refers to how an existing crack or microscopic flaw in a material propagates or extends over time when the component is subjected to mechanical loads, cyclic stresses, or high temperatures.
Crack growth direction – It refers to the spatial path or angle along which an existing crack extends through a material under applied mechanical loads or environmental conditions.
Crack growth equation – It is a mathematical formula used to predict how fast a microscopic crack in a metal part gets bigger when the part faces repeated pulling and pushing forces over time.
Crack growth history – It is the record of the progression of crack lengths over time in a material, frequently computed using equations such as the NASGRO equation, and is analyzed to predict the effects of stress conditions on crack propagation in test samples.
Crack-growth rate – It is the rate of propagation of a crack through a material because of the statically or dynamically applied load.
Crack growth resistance – It is a material’s ability to withstand the propagation of an existing crack under applied stress.
Crack growth resistance curve – It shows the energy needed for crack extension as a function of crack length in a given material. For materials which can be modelled with linear elastic fracture mechanics (LEFM), crack extension occurs when the applied energy release rate exceeds the material’s resistance to crack extension. A plot of crack growth resistance against crack extension is called a crack growth resistance curve, or R-curve.
Crack growth threshold – It is the limiting value of the stress intensity factor range below which a fatigue crack does not propagate or grows at a negligibly slow rate. It represents the lower vertical asymptote of the fatigue crack growth rate curve (Region I) where the crack propagation rate approaches zero.
Crack healing – It is the process where a fracture or micro-crack in a material closes and bonds back together, either autonomously (self-healing) or through external intervention or environmental conditions, restoring part or all of the material’s original mechanical properties and durability.
Crack, hot – A hot crack is a fracture which forms in a metal casting near the end of solidification. It happens when high temperature shrinkage stress pulls apart weak grain boundaries which still contain thin liquid films.
Crack, hot tear – Hot tear crack is a fracture which happens in a metal casting during the final stage of solidification when the metal is weak, partially solid and partially liquid, and unable to withstand shrinkage and thermal stresses.
Crack identification – It is the process of detecting, locating, and sizing fractures or material separations in structures, machinery, and components before they lead to structural failure.
Crack image quality indicator – It is a specialized, standard calibration tool used in digital radiography or industrial computed tomography to verify that the inspection set-up is sensitive enough to detect fine, linear cracks. Unlike conventional ‘image quality indicators’ (IQIs) which utilize round wires or drilled holes to measure overall density and contrast, a a crack image quality indicator (CIQI) contains simulated, tightly controlled micro-cracks or representative linear discontinuities. It serves as an objective reference standard to ensure that low-contrast, highly oriented flaws are not missed because of the poor technique or image noise.
Crack increment – It is frequently denoted as ‘da’. It is the new extension or growth length of a crack during a single step of loading, a specific time interval, or a numerical calculation. It represents the change in crack length (da) per unit of time or per loading cycle (dN) as a material undergoes stress.
Crack-indicator method – It consists of specifically utilizing a crack image quality indicator (CIQI) or crack reference standard. It refers to a precise calibration and verification method used to determine and validate the capability of an inspection set-up to reliably identify tightly closed, microscopic, or volumetric cracks within a metallic component. Instead of trying to locate unknown cracks blindly, this method introduces a certified artifact or mathematical simulation featuring artificial, predefined defects (such as micro-slits or simulated crack morphologies) directly into the test environment to evaluate the system’s sensitivity limit.
Cracking – In coatings, it consists of breaks in the coating which extend through to the underlying surface. In lubrication technology, cracking is the process of converting unwanted long-chain hydro-carbons to shorter molecules by thermal or catalytic action.
Cracking behaviour – It refers to the response of concrete under tensile stress, characterized by the formation of cracks as the material reaches its tensile strength, which influences the dynamic response of structural elements. This behaviour can be modelled using different approaches, such as the fictitious crack model, which accounts for cohesive stresses and crack width development following initial cracking.
Cracking furnace – It is also called steam cracker. It is a high-temperature industrial reactor used to break large hydrocarbon molecules, like ethane, LPG (liquefied petroleum gas) , or naphtha, into lighter, high-value olefins such as ethylene and propylene.
Cracking mechanism – It is the physical or chemical process by which a material develops and grows a fracture under mechanical loads, thermal gradients, or environmental exposure.
Cracking performance – It defines a material’s or structure’s ability to withstand internal and external stresses without developing or propagating structural fractures. It evaluates either a failure metric to be minimized (as in civil and materials engineering) or a highly controlled structural asset (as in flexible sensor electronics).
Cracking prediction – It is the analytical and numerical process of forecasting when, where, and how fractures or splits are going to initiate and propagate in materials and structures.
Cracking pressure – It is the minimum pressure differential (inlet pressure minus outlet pressure) needed to slightly open a valve, such as a check valve or relief valve, so that the first detectable sign of fluid or gas flow occurs.
Cracking resistance – It is a material’s ability to withstand load-induced stresses, deformations, or environmental factors without initiating or propagating cracks that lead to structural failure.
Cracking strip – It is a small fin or projection of extra metal moulded directly onto the surface of a casting. Its purpose is to absorb thermal contraction and mechanical stresses during cooling, preventing hot tears or cracks from forming in the main casting body.
Cracking susceptibility – It refers to the likelihood of an alloy experiencing cracks during solidification, which can be evaluated through different tests designed to assess internal stresses and external loads affecting the material. This concept is pivotal for understanding potential structural failures in components because of the impaired mechanical properties.
Crack initiation – It is the initial stage where a microscopic crack or nucleation site forms because of the localized plastic deformation, stress concentration, or structural defects.
Crack initiation, fatigue – Fatigue crack initiation is the process by which cracks form on the surface or at internal sites of a material because of the stress concentration associated with surface flaws, defects, or microstructural features such as porosity. Factors like hard, non-shearable particles and a fine grain structure enhance resistance to this initiation. Fatigue crack initiation is the first phase of fatigue failure where a microscopic crack forms on a material’s surface or internal structure due to repeated (cyclic) stress well below the material’s yield strength.
Crack initiation life – It is the number of loading cycles (or time) needed for a microscopic crack to nucleate and grow to a defined ‘technical’ size (typically about 0.5 millimeters in depth or spanning the first few crystal grains) on or near the surface of a material under cyclic or static stress.
Crack length – It is also called crack depth. In fatigue and stress-corrosion cracking, the physical crack size is used to determine the crack growth rate and the stress-intensity factor. For a compact-type sample, crack length is measured from the line connecting the bearing points of load application. For a centre-crack tension sample, crack length is measured from the perpendicular bisector of the central crack.
Crack mitigation – It refers to the strategies, design methods, and manufacturing techniques used to prevent the initiation of cracks, slow down crack propagation, and improve the damage tolerance of materials and structures.
Crack motion – It is also called crack propagation motion. It refers to the physical movement and growth of a crack tip through a material under applied mechanical loads, thermal stresses, or environmental conditions.
Crack mouth – It is the outer opening or entry point of a crack, notch, or fatigue-cracked defect located on the surface of a structural member or test sample.
Crack mouth opening displacement – In a plane strain fracture toughness test sample, it is the opening displacement of the notch surfaces at the notch and in the direction perpendicular to the plane of the notch and the crack. The displacement at the mouth is called the crack mouth opening displacement (CMOD).
Crack opening displacement – In a plane strain fracture toughness test sample, it is the opening displacement of the notch surfaces at the notch and in the direction perpendicular to the plane of the notch and the crack. The displacement at the tip is called the crack tip opening displacement (CTOD), and that at the mouth, it is called the crack mouth opening displacement (CMOD).
Crack path – It is the physical trajectory or course a crack takes as it propagates through a material or component.
Crack, perpendicular – A perpendicular crack is a fracture which propagates, or lies, at a 90-degree angle (right angle) relative to a specific reference line, axis, or boundary.
Crack plane – It is the assumed or actual surface or cross-section within a material where a crack propagates or is predicted to develop.
Crack plane orientation – It is an identification of the plane and direction of a fracture in relation to product geometry. This identification is designated by a hyphenated code, the first letter(s) representing the direction normal to the crack plane and the second letter(s) designating the expected direction of crack propagation.
Crack plane orientation and growth direction system – It is a three-letter identification system used to identify the longitudinal (L), transverse (T), and short transverse (S) direction of the applied stress normal to the plane on which the crack propagates and the direction of crack growth. It is used for both prismatic and cylindrical sections. For example, a L-T orientation indicates a stress in the longitudinal (or rolling) direction, and crack propagation is in the wide transverse direction.
Crack prediction – It is the method used to forecast when, where, and how cracks are going to form, spread, or grow in materials and structures before they cause failure.
Crack problem – It refers to the physical analysis and management of a material discontinuity or line-shaped void which reduces a component’s cross-sectional area, concentrates stress at its tip, and threatens structural integrity under external or internal loads.
Crack profile – It refers to the 2D or 3D geometric shape, size, depth, width variation, and path of a physical separation or fracture (crack) within a material or structural component.
Crack-prone materials – These are substances which easily develop fractures or splits when exposed to stress, temperature changes, or environmental pressure.
Crack propagation – It is a process of evolutionary geometry influenced by high values and gradients in crack front fields, accompanied by material damage. It involves predicting material damage, computing local field quantities, and evolving geometry, frequently needing integration across different length scales.
Crack propagation life – It refers to the duration over which a crack grows from an initial size to a final size under cyclic loading conditions, calculated through the integration of crack propagation equations, such as those described by Paris law.
Crack propagation path – It is the physical trajectory or course a crack follows as it extends through a material under mechanical, thermal, or environmental loading.
Crack propagation rate – It is the speed at which a crack extends or grows through a metal under applied stress, normally expressed as the change in crack length per load cycle (da/dN) for fatigue or per unit of time (da/dt) for creep or stress corrosion.
Crack propagation speed – It is the rate at which the tip of a fracture advances through a solid material over time, typically measured in meters per second or characterized under cyclic loads as crack growth per cycle (da/dN).
Crack reference standard – It is also known as a calibration standard or reference block. It is a precisely manufactured material sample containing engineered, artificial discontinuities of known sizes used to calibrate inspection equipment and verify defect detection sensitivity. It is framed by how the physical block matches the material properties of the parts being tested to ensure accurate flaw evaluation.
Crack repair– It refers to the process of addressing fractures or fissures in structures and materials to restore their load-bearing integrity, functional performance, appearance, and durability.
Crack resistance – It refers to the ability of a material to withstand crack growth under stress, characterized by the crack-resistance curve (R-curve), which measures the crack-driving force as a function of stable crack extension. It is influenced by both intrinsic mechanisms which operate ahead of the crack tip and extrinsic mechanisms which shield the crack from the applied driving force.
Crack resistance curve it is a graph of resistance of a material to slow, stable crack extension, expressed in the same units as the stress intensity factor, or the crack extension force as a function of the amount (length) of slow, stable crack extension. Comparison of the crack driving forces with this curve provides an estimate of the conditions for crack growth instability.
Crack shape – It refers to the geometric configuration of cracks and crack-like flaws, which are frequently assumed to have an idealized planar shape for simplicity in analysis.
Crack size – It is a lineal measure of a principal planar dimension of a crack. This measure is normally used in the calculation of quantities descriptive of the stress and displacement fields. In practice, the value of crack size is got from procedures for measurement of physical crack size, original crack size, or effective crack size, as appropriate to the situation under consideration.
Crack speed – It is the rate at which the tip of a crack moves through a material under mechanical stress. It measures how fast a fracture front advances across or through a solid structure.
Crack surface – It refers to the exposed, free internal or external boundary faces created when a solid material undergoes a fracture or physical separation.
Crack surface displacement – It refers to the relative movement, separation, or sliding of points on the opposite faces of a crack when a structural component is subjected to external loads. It describes how the two sides of a crack pull apart, shear, or tear relative to each other.
Crack susceptibility – It is the relative likelihood that a material or weld is going to develop fractures or cracks when exposed to internal stresses, shrinkage during cooling, or external loads.
Crack susceptibility coefficient – It is a numerical index used to measure an alloy’s vulnerability to hot cracking (or hot tearing) during solidification in casting or welding.
Crack test – It is a quality assurance or mechanical evaluation method used to detect, locate, and measure flaws, micro-cracks, or structural damage in materials and components.
Crack tip – It is the single point where a crack propagates in a material, with its characteristics varying depending on whether the material is brittle or ductile. In brittle materials, the crack tip is sharp and more susceptible to propagation, whereas in ductile materials, the presence of ductile phases leads to crack-tip blunting, which improves fracture toughness.
Crack tip fields – These fields refer to the asymptotic elastic stress and displacement fields which occur near the tip of a crack in a material, characterized by stress intensity factors which depend on the geometry and applied loads. These fields are critical for understanding the behaviour of materials under stress and for predicting crack propagation.
Crack tip opening – It refers to the displacement at the tip of a crack, which cannot be measured directly and is to be inferred from the crack mouth displacement in elastic-plastic fracture mechanics. It is a critical parameter used in industry applications to characterize fracture behaviour.
Crack tip opening angle – It is the angle formed by the two cracking flanks (faces) near the tip of a crack in a material. It serves as a key fracture-mechanics parameter used to measure a material’s resistance to plastic or stable crack growth (tearing), particularly in ductile metals and thin-sheet structures under plane-stress conditions. It is the local angular opening between the upper and lower faces of a crack, measured starting from or a short distance (typically around 1 millimeter, behind the crack tip.
Crack tip opening displacement – In a plane strain fracture toughness test sample) it is the opening displacement of the notch surfaces at the notch and in the direction perpendicular to the plane of the notch and the crack. The displacement at the tip is called the crack tip opening displacement (CTOD).
Crack tip plane strain – It is a stress-strain field, near a crack-tip, which approaches plane strain to the degree needed by an empirical criterion.
Crack tip plastic zone – It is the localized region of permanent, irreversible plastic deformation surrounding the tip of a crack in a metal or other ductile material.
Crack tip position – It is the location of the crack interior surface atom with the maximum coordinate in the direction of crack growth, which can be identified using the centro-symmetry parameter ‘P’ to distinguish surface atoms from those near defects.
Crack tip region – It is the critical local area at the very end or point of a crack in a material where the highest stress concentrations occur and where crack advance or propagation takes place.
Crack tip state – It refers to the localized mechanical, geometric, and material condition at the absolute front of a propagating or stationary crack. It dictates whether a metal is going to undergo stable deformation, slow fatigue growth, or catastrophic brittle failure. Since an ideal sharp crack mathematically generates infinite stress (a stress singularity), a real metal responds by changing its localized ‘state’ through microstructural yielding and geometric alteration.
Crack tip strain rate – It is the rate of localized deformation (strain per unit of time) occurring directly at or immediately adjacent to the tip of a crack in a material.
Crack tip stress – It refers to the intense, localized stress field that builds up at the very end of a crack in a material. Since a crack act as a severe stress concentrator, the forces in this microscopic region are drastically higher than the nominal (average) stress applied to the overall structure.
Crack tip stress field – It refers to the stress and strain distribution around the tip of a crack in elastic materials, which can be analyzed using fracture mechanics to understand crack growth behaviour.
Crack velocity – It is also called crack propagation velocity. It is the speed at which the tip of a crack advances through a material under applied stress or dynamic loading. It measures how fast a fracture front moves across a cross-section or area of a solid component, expressed in units of distance per time (e.g., meters per second).
Crack, wall – It refers to a fracture, split, or separation which develops in masonry, concrete, plaster, or dry-wall when internal or external stresses exceed the tensile or shear strength of the building material.
Cradle rolls – These rolls refer to specific types of rolls used to support and guide the metal strip as it passes through the mill. They are designed to minimize imperfections and ensure consistent quality of the finished product.
Cradle-to-cradle (C2C) concept – It is a closed-loop approach. It refers to an approach in which materials are viewed as nutrients circulating in closed loops, promoting the idea that everything is used without generating wastage, hence maximizing material value while preventing damage to ecosystems.
Cradle-to-gate analysis – It is a partial life cycle assessment (LCA) which measures a product’s environmental impacts from the extraction of raw materials (cradle) up to the point it leaves the manufacturer’s facility (gate), before it is shipped to the consumer.
Cradle-to-gate assessment – It is a partial life cycle assessment (LCA) which measures a product’s environmental footprint from the extraction of raw materials (cradle) up to the point it leaves the manufacturer’s factory gate (gate), before it is transported to the consumer.
Cradle-to-grave – Cradle-to-grave assessment considers impacts at each stage of a product’s life-cycle, from the time natural resources are extracted from the ground and processed through each subsequent stage of manufacturing, transportation, product use, and ultimately, disposal.
Cradle-to-grave assessment – It is a comprehensive life cycle assessment (LCA) which evaluates the total environmental impact of a product, material, or system across its entire lifespan, starting from raw material extraction (cradle) through manufacturing, distribution, use, maintenance, and final waste disposal or land-filling (grave).
Cramer’s rule – It is defined as a method for directly computing the solution to a system of linear equations, using determinants, provided one exists. It applies to linear systems in multiple variables, allowing the calculation of variable values through determinant expressions.
Crane – Cranes are industrial machines which are mainly used for materials movements in construction sites, production shops, assembly lines, storage areas, power stations and similar places. Their design features vary widely according to their major operational specifications such as type of motion of the crane structure, weight and type of the load, location of the crane, geometric features, operating mechanisms, and environmental conditions. Cranes play an important role in the handling of materials by raising and moving loads, the mass of which is within their nominal capacity. There can, however, be wide variations in the duty, both for a single crane type, for example overhead travelling cranes, or between different crane types, for example between a builder’s tower crane and a heavy-lift dockside crane. The design of the crane has to take into account the conditions of service, in order to reach an appropriate level of safety and useful life.
Crane barge – It is an offshore barge which has a sheer-legs crane or fully rotating crane. A sheer-legs crane can pick loads and luff but not swing. The sheer legs consist of an A-frame made up of two heavy, tubular members or trussed columns held back by heavy stays to the bow.
Crane boom – The boom of a crane is the long, main arm which extends outward from the main body to lift, lower, and move heavy loads.
Crane capacity – It is the rated load, which is required to be lifted. Rated load means the maximum load for which a crane or individual hoist is designed and built by the manufacturer and shown on the equipment identification plate. The rated capacity of crane is the live load which can be lifted by the crane. The rated load is defined as the maximum working load suspended under the load hook. Load block and ropes are not included in the rated load.
Crane clearance – It is the vertical distance between the grade level and the bottom of the crane girder.
Crane, gantry – A gantry crane is a self-supporting lifting machine with a horizontal bridge resting on floor-mounted legs which move on tracks.
Crane, jib – A jib crane is an industrial lifting device with a horizontal arm (the jib or boom) mounted to a wall or vertical pillar.
Crane, mobile – A mobile crane is a self-powered lifting machine with a telescoping or lattice boom mounted on a truck or crawler carrier, designed to move easily between sites.
Crane rail – It is a specialized type of rail designed for supporting and guiding the movement of cranes. It is essentially a track which allows cranes to travel horizontally, enabling them to lift and move heavy loads within a work area. Unlike standard railway tracks, crane rails are designed with a specific geometry and material properties to withstand the heavy loads and forces exerted by cranes.
Crane span – It is the distance between columns across the width of the building. Building width is defined as the distance from outside of the eave strut of one sidewall to outside of the eave strut of the opposite sidewall. Crane span is the horizontal centre distance between the rails of the runway on which the crane is to travel. Typical distance is around 500 millimetres less than the width of the building. The requirement of the span of the crane depends on the crane coverage width dictated by the application.
Crane scales – They consist of dynamometer placed between lifting hoist and the load to indicate the weight of the load.
Crane steel structure – It has a single or double girder crane construction as per the span and the maximum load handling capacity.
Crane vessel – It also called a floating crane or heavy-lift vessel. It is a specialized ship or barge equipped with one or more high-capacity cranes designed for heavy lifting, marine construction, and offshore engineering operations.
Crane, wall jib – A wall-mounted jib crane is a localized lifting device featuring a horizontal arm (the jib) bolted directly to a structural wall or building column. It supports a movable hoist to lift and rotate heavy loads in a 180-degree to 200-degree semi-circle without using any floor space.
Crane wheel – It is also known as a wheel block or wheel assembly. It is an important component of cranes, enabling them to move along designated tracks or runways. These wheels are designed to support the crane’s weight and the load it’s carrying, ensuring smooth and reliable movement. They typically consist of a wheel, an axle, and bearings, all working together to facilitate controlled motion.
Crank – It is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice-versa.
Crank angle in mechanical and automotive engineering is the angular position of an engine’s crankshaft measured relative to a specific reference point, typically top dead centre (TDC).
Crank arm – It is a lever attached at a right angle to a rotating shaft (or forming an offset portion of a shaft) which converts circular motion into reciprocating motion, or reciprocating motion into circular motion.
Crank-case – It is the metal housing or structural enclosure in an internal combustion engine or reciprocating pump which surrounds and supports the crank-shaft, connecting rods, and related components.
Crank-case door – It normally refers to one of two things depending on the context namely a standard inspection access panel or a crank-case explosion relief door (safety valve). Crank-case access panel is a removable cover or panel bolted onto the crank-case housing of medium-sized to large-sized engines (such as stationary diesel engines). 2. Crank-case explosion relief door is a spring-loaded or weight-loaded safety device installed on the crankcase walls (frequently one per cylinder) of large internal combustion engines.
Cranking capability – It refers to the ability of a power source, very frequently a battery or an auxiliary starter system, to deliver the high electrical current and torque needed to start an internal combustion engine or activate a large mechanical system from a dead stop.
Crank mechanism – It is a mechanical device which converts circular (rotational) motion into back-and-forth (reciprocating or linear) motion, or the other way around. It is also known as the slider-crank linkage, which powers car engines, pumps, and compressors.
Crank–Nicolson method – It is a finite difference numerical technique used to solve the heat equation and other parabolic partial differential equations (PDEs). It works by approximating spatial derivatives using a 50-50 weighted average of the current time step and the future time step.
Crank pin bearing – It is a bearing at the larger (crankshaft) end of a connecting rod in an engine. It is also known as bottom-end bearing, crankpin bearing, and large-end bearing.
Crank press – It is a mechanical press whose slides are actuated by a crank-shaft.
Crank presses with modified drives – These are specialized mechanical power presses where the standard single-crank or eccentric drivetrain is integrated with secondary linkages or specialized control systems to alter the linear displacement, velocity, and force profiles of the press slide (ram). Unlike traditional crank presses which generate a symmetric, sinusoidal slider-velocity curve, a modified drive decouples the ram’s movement from strict harmonic motion. This allows the designers to optimize the ‘law of motion’ for specific metalworking operations.
Crankshaft – It is a mechanical part which is able to perform a conversion between reciprocating motion and rotational motion. In a reciprocating engine, it translates reciprocating motion of the piston into rotational motion, whereas in a reciprocating compressor, it converts the rotational motion into reciprocating motion. In order to do the conversion between two motions, the crankshaft has ‘crank throws’ or ‘crankpins’, additional bearing surfaces whose axis is offset from that of the crank, to which the ‘big ends’ of the connecting rods from each cylinder attach.
Crankshaft bearings – These are components in an internal combustion engine which support the crankshaft and are hydro-dynamically lubricated, allowing them to carry heavy loads from firing and inertia without suffering damage. They typically consist of a steel backing with a thin lining of bearing alloy, which are to have sufficient strength to endure dynamic pressures generated in the oil film.
Crankshaft speed – It is the rate of rotation of an engine’s crankshaft, defined as the number of full revolutions it completes per unit of time.
Crank shears – These shears can be designed as (i) continuously running shears, (ii) start-stop shears, and (iii) coupling shears with coupling- brake combination. These shears are used for cropping, dividing, or emergency cutting during cobble. Shear start is initiated by pulse generator. Crank shears can be crank lever shear or double crank shears.
Crash box – It is an energy-absorbing structural component in a vehicle, positioned between the front bumper beam and the main chassis side rails (or front frame).
Crashing – In critical path method (CPM), crashing an activity refers to taking on extra expenditures in order to reduce the duration of an activity below its expected duration. It is a term which describes the process of reducing the time needed to complete an activity. Crash point shows the time and cost when the activity is fully crashed.
Crashing time – It is the minimum possible time for completion of an activity, corresponding to maximum resource concentration. Crash cost is the cost needed to achieve the crash time.
Crashworthiness – It is the ability of a structure, such as an automobile, or train.to protect its occupants during an impact and minimize the risk of severe injury or death.
Crashworthy structure – It is a design, very frequently in vehicles, or trains, which manages kinetic energy during an impact by undergoing controlled plastic deformation while preserving a safe, uncompromised survival space for occupants.
Crater – In arc welding, it is a depression at the termination of a weld bead or in the molten weld pool. In refractories, crater is a clearly defined hole in the surface of a brick whose parameters, maximum diameter, minimum diameter and depth can be measured.
Crater crack – It is a crack in the crater of a weld bead. It is a hot thermal crack (or solidification crack) which forms in the depression, or crater, left at the end of a weld bead when the welding arc is abruptly broken.
Cratering – It is the depressions on coated surfaces caused by excess lubricant. Cratering results when paint is too thin and later ruptures, leaving pinholes and other voids. Use of less-thinner in the coating can reduce or eliminate cratering, as can the use of less lubricant on the part.
Crater wear – It is the wear which occurs on the rake face of a cutting tool because of the contact with the material in the chip which is sliding along that face.
Crawler crane – A crawler is a crane mounted on an undercarriage with a set of tracks which is also called crawlers. These crawlers provide stability and mobility to the crane. Crawler cranes have both advantages and disadvantages depending on their use. Their main advantage is that they can move around on site and perform each lift with little set up, since the crane is stable on its tracks with no outriggers. A crawler crane is also capable of travelling with a load. The main disadvantage is that these cranes are very heavy, and cannot easily be moved from one job site to another without significant expense. Typically, a large crawler is to be disassembled and moved by trucks, rail cars or ships to its next location. Crawler cranes range in lifting capacity from around 35 tons to 3,000 tons.
Crawling – In porcelain enamel, It is a condition similar to tearing which occurs when firing a sprayed enamel coating over another coating already fired. It is characterized by the aggregation of the top-coat into balls or irregularly shaped islands during firing, hence exposing the base coat layer.
Craze cracking – it is the irregular surface cracking of a metal associated with thermal cycling.
Craze cracks – These cracks refer to a network of fine, shallow, hair-like surface cracks resembling a web or tiny hexagons. These cracks happen when metal, ceramic moulds, or glazed surfaces cool unevenly or experience sudden thermal and shrinkage stress.
Crazing – It is also called worming. It is a network of fine hairline cracks in a coating. It is also cracking which occurs in fired glazes or other ceramic coatings because of the critical tensile stresses. In porcelain enamel, it is almost-invisible lines in the finished surface which extend down to the base metal. It is also a macroscopic effect of numerous surface tears, transverse to the rolling direction, which can occur when the entry angle into the cold mill work rolls is large.
Cr depletion – It is a localized reduction in chromium concentration near alloy grain boundaries or surfaces, which strips the material of its corrosion resistance and causes a state known as sensitization.
Crease – It is a sharp deviation from flat in the sheet which is transferred from processing equipment subsequent to the roll bite.
Create joints – It refers to the process of manually defining connections between components in a mechanical assembly, utilizing tools such as the insert joint tool to specify joint types and their axes, ensuring proper alignment and function of the assembled parts.
Create key-points – It refers to the process of defining specific points in a coordinate system within software by inputting their ’x’, ’y’, and ‘z’ locations to facilitate modelling and analysis. This process involves selecting options in the software’s interface to input and apply the coordinates, resulting in the visualization of these points in the graphic window.
Creating joints – It refers to the process of establishing connections between components in a dynamic simulation study, which can be performed through standard joints which utilize assembly constraints or non-standard joints which do not, enabling the simulation of motions, forces, and interactions within the assembly.
Creative concept development – It includes the stages of idea generation, communicative prototyping, creation and refinement of concepts in an iterative approach. The development activities start from an initial description of a challenge.
Creative process – It is a total problem resolution process which yields a truly new solution to the problem. A creative solution needs both vertical thinking (convergent thinking) and lateral thinking (divergent thinking).
Credible source – It is a provider of technical information, such as a standard, or expert institution, which is trustworthy, verifiable, and backed by empirical data or rigorous testing.
Creel – It is a device for holding the required number of roving balls (spools) or supply packages in desired position for unwinding onto the next processing step, that is, weaving, braiding, or filament winding.
Creep – Creep is the property of materials which results in progressive deformation when a constant load is applied over time. Deformation occurs as a result of long-term exposure to high levels of stress which is still below the yield strength of the material. It is the time-dependent strain occurring under stress. The creep strain occurring at a diminishing rate is called primary creep, that occurring at a minimum and almost constant rate is called secondary creep, and that occurring at an accelerating rate is called tertiary creep. In refractories, it is creep in compression which is isothermal deformation of a stressed refractory as a function of time.
Creepage distance – It is the minimum distance along the surface of an insulating material between two conductive parts, which is critical for preventing electrical arcing and ensuring safety against electrocution or fire hazards in electrical circuits. It varies based on the application and is influenced by factors such as working voltage and environmental conditions.
Creep behaviour – It is the slow, continuous, and permanent deformation of a solid material which occurs when it is subjected to a constant mechanical load or stress over a long period of time. Unlike normal elastic or plastic deformation which happens immediately, creep happens gradually and frequently occurs at stress levels well below the material’s yield strength. It is heavily accelerated by high temperatures (typically above 0.4 times to 0.5 times the material’s absolute melting point), though some materials like polymers can creep at room temperature.
Creep compliance function – It is a mathematical representation which describes how a material deforms over time under a constant load, typically expressed in terms of elastic modulus and fitting parameters which account for aging and non-aging effects.
Creep constitutive equation – It is a mathematical formula which relates a material’s time-dependent deformation (creep strain or creep strain rate) to applied stress, temperature, and time.
Creep crack growth – It is the time-dependent extension of a pre-existing crack in a material under a sustained, constant load at high temperatures.
Creep cracking – It is the process where fractures develop and extend in a material subjected to sustained mechanical stress over a long period at elevated temperatures.
Creep deformation – It is a permanent inelastic strain which occurs when a material is subjected to a sustained stress. The rate at which this deformation occurs depends not only on the magnitude of the applied stress, but also on time and temperature.
Creep exponent – It is a dimensionless material parameter which describes how strongly the steady-state creep rate of a material responds to changes in applied stress. It is a parameter in the power-law creep formulation which characterizes the relationship between creep rate and stress, specifically indicating how the creep rate changes with applied stress over time.
Creep-feed grinding – It is a grinding process which produces deeper cuts at slow traverse rates.
Creep force – It is the tangential friction force that develops in the plane of the contact patch between a rolling element and a track, very frequently between a train wheel and a steel rail. It needs a certain quantity of slip (creep) to occur. It is influenced by factors such as normal load, friction conditions, and the relative motion of the contacting surfaces.
Creep function – It is a mathematical representation which describes how strain accumulates in a material over time under a constant sustained load.
Creep-hardening – It is frequently referred to as strain hardening or work hardening during the primary stage of creep. It is the process where a material becomes more resistant to deformation as it slowly stretches under a constant load over time.
Creep-hardening parameter – It is a mathematical constant used in constitutive models to predict how a material’s resistance to time-dependent plastic deformation (creep) changes as a function of prior strain or time under high temperatures.
Creeping flow – It is a type of fluid flow which occurs at low Reynolds numbers, where inertial forces are negligible, allowing the Navier-Stokes equations to simplify to a linear mathematical form similar to heat conduction or diffusion equations.
Creeping-spindle swaging – It is a specialized variation of the rotary swaging metal-forming process where both the machine’s spindle and the roller cage revolve in opposite directions.
Creep law – It is a mathematical formula which predicts how much a solid material permanently deforms over time when subjected to a constant mechanical stress, typically at high temperatures.
Creep life-time – It is the total duration a material or component can withstand a constant load or stress before it permanently deforms to a failure threshold or breaks completely (known as creep rupture).
Creep limit – It is the maximum stress which causes less than a specified quantity of creep in a given time. It is also the maximum nominal stress under which the creep strain rate decreases continuously with time under constant load and at constant temperature. Sometimes it is used synonymously with creep strength.
Creep mechanisms – These are the atomic-scale processes which cause a material to deform slowly and permanently over time when subjected to a constant mechanical stress at high temperatures.
Creep model – It is a mathematical framework used to predict the time-dependent deformation of materials subjected to a constant mechanical stress over a long period.
Creep phenomenon – It is a slow, continuous deformation of a material under constant stress, characterized by an initial instantaneous strain followed by progressive strain increase, and typically occurs in three stages namely primary, secondary, and tertiary. This behaviour is particularly important in materials such as polymers, which can experience creep even at room temperature, affecting their stability and performance under applied stresses.
Creep range – It is the temperature range, typically starting at roughly 30 % to 50 % of a material’s absolute melting point (Tm in Kelvin), where a material experiences slow, time-dependent, and permanent deformation under a constant load or stress below its yield strength.
Creep rate – It is the slope of the creep-time curve at a given time. It is the deflection with time under a given static load.
Creep ratio – In a ball bearing, it is the ratio of the creep velocity to sweep velocity.
Creep recovery – It is the time-dependent decrease in strain in a solid, following the removal of force.–
Creep resistance – It is a material’s ability to withstand permanent, time-dependent deformation when subjected to a constant mechanical stress at high temperatures. It refers to the ability of a material to withstand permanent deformation under static mechanical stress at high temperatures, as indicated by lower creep strain rates in materials.
Creep-resistant austenitic steel – It is a specialized category of face-centered cubic (fcc) iron-based alloy designed to maintain structural integrity, resist permanent slow deformation, and avoid mechanical failure under long-term static stress at high temperatures (typically between 550 deg C and 700 deg C).
Creep-rupture – It is the tensile fracture of a material subjected to sustained high stress levels over a period of time and occurs when a material strain capacity is reached.
Creep rupture data – It is the collection of measurements from mechanical tests showing how long a material takes to fracture when subjected to a constant static load at high temperatures.
Creep rupture elongation – It is the proportion, expressed in percentage of the original length, by which a test piece made from a material extends before fracture.
Creep-rupture embrittlement – It is the embrittlement under creep conditions. Failure occurs by intergranular cracking of the embrittled material.
Creep rupture properties – These properties refer to the characteristics of a material’s resistance to time-dependent deformation and fracture under constant stress at high temperatures, which considerably impact the structural design of components used in high-temperature applications.
Creep-rupture strength – It is the stress which causes fracture in a creep test at a given time, in a specified constant environment. This is sometimes referred to as the stress-rupture strength.
Creep rupture stress – It is the stress at which a test piece made from a material gets fractured when held for a specified time at a specified temperature.
Creep-rupture test – It is a test in which progressive sample deformation and the time for rupture are both measured. In general, deformation is much higher than that developed during a creep test. It is also known as stress-rupture test.
Creep settlement – It is the slow, time-dependent downward movement of soil or a structure which continues under a constant, sustained load. It begins only after main consolidation (the squeezing out of pore water) is completely finished.
Creep stage – It refers to the distinct phases of deformation experienced by metallic materials under constant load at high temperatures, which includes primary, secondary, and tertiary stages, each characterized by specific strain rates and microstructural changes.
Creep straightening – It is a controlled thermal process used to remove distortions, warps, or bends from metal parts by utilizing the material’s ‘creep’ property under heat and tension.
Creep strain – It is the time-dependent total strain (extension plus initial gauge length) produced by applied stress during a creep test. It is the time-dependent deformation which occurs in a material when subjected to a constant mechanical load, influenced by the stress level, duration of the load, and temperature.
Creep-strain limit – It is the maximum allowable permanent deformation (strain) a material or component can accumulate over time under constant mechanical load and high temperature before it is considered functionally failed or unsafe.
Creep-strain rate – It is the speed at which a material permanently deforms over time when subjected to a constant mechanical load and elevated temperature.
Creep strength – It is the stress which causes a given creep strain in a creep test at a given time in a specified constant environment.
Creep stress – It is the constant load divided by the original cross-sectional area of the sample. It is the stress at which a test piece made from a material strain by a specified proportion (frequently 1 %) when held for a specific time at a specific temperature.
Creep test – It is a method of determining the extension of metals under a given load at a given temperature. The determination normally involves the plotting of time-elongation curves under constant load. A single test can extend over several months. The results are frequently expressed as the elongation (in millimeters) per hour on a given gauge length (e.g., 25 millimeters).
Creep testing – It is a procedure which measures the time-dependent, permanent deformation (elongation or strain) of a material under a sustained, constant mechanical load or stress at a fixed temperature.
Creep test results i- These results refer to the experimental data and parameters measured when a material is subjected to a constant mechanical load (stress) at a sustained (frequently high) temperature over a prolonged period.
Creep types – Types of creep by physical mechanism are dislocation creep (power-law creep), diffusional creep, grain boundary sliding, irradiation creep, and concrete creep (basic and drying creep). Dislocation creep (power-law creep occurs at higher stress levels and intermediate-to-high temperatures. Dislocations move through the crystal lattice through slip and thermal activation-assisted ‘climb’ to bypass obstacles. Diffusional creep occurs at lower stress levels and very high temperatures where atoms or vacancies diffuse through the material. Diffusional creeps are Nabarro-Herring creep in which diffusion of vacancies takes place directly through the crystal lattice (interior) of the grains, and Coble creep in which diffusion of atoms or vacancies happens preferentially along the grain boundaries, making it more prominent in fine-grained materials. In grain boundary sliding, adjacent grains shear or slide past one another along their common boundaries, frequently contributing to high-temperature deformation and intergranular cracking. Irradiation creep is seen in nuclear engineering applications where continuous bombardment by high-energy neutrons induces point defects, causing deformation even at lower temperatures. In concrete creep (basic and drying creep), concrete experiences creep divided into basic creep (under constant moisture) and drying creep (because of the simultaneous loss of moisture / pore.
Cresol – Cresols (also known as hydroxytoluene, toluenol, benzol or cresylic acid) are a group of aromatic organic compounds. They are widely-occurring phenols (sometimes called phenolics) which can be either natural or manufactured.
Creosote oil – It is also known as wash oil and has boiling range of 230 deg C to 290 deg C. It is reported to have some 162 compounds. However, only a limited number (lesser than 20) are at levels exceeding 1 % but these constitute the major portion of creosote oil. It contains besides small amounts of naphthalene, naphthalene derivatives, indole, diphenyl, acenaphthene, diphenylene oxide, fluorene, phenol derivatives (2 %) and quinoline base (4 % to 6 %).
Crested structure – It is an installation designed with a top horizontal or near-horizontal surface (the crest) positioned at, slightly above, or submerged below the design water level.
Crested weir – It is an elevated obstruction built across an open channel or river to control water levels, regulate flow, or measure the volume rate of discharge. The crest is the top edge or surface of the weir over which the water flows.
Crest factor – It is the ratio of a waveform’s peak value to its root mean square (RMS) value. It measures how spiky, impulsive, or extreme a signal is compared to its effective energy level. ‘Crest factor (CF) = (peak value) / (root mean square value’).
Crest freeboard – It is the vertical distance between the crest elevation of a hydraulic structure (such as a dam, breakwater, or open channel wall) and the water surface level.
Crest width – It is the horizontal measurement of the top most flat, rounded, or raised surface of a structure or mechanical component. In weirs, it is the width of the raised horizontal surface (sill) of a broad-crested weir in the direction of fluid flow. In earth-fill / concrete dams, It is the horizontal thickness of the dam measured across its top from the upstream face to the downstream face. In break-waters and sea-walls, it is the horizontal distance measured across the top of a coastal structure, such as from the back of the beach to the top edge of the beach face slope, or across the top of a break-water / barrier.
Crevice corrosion – It refers to the corrosion occurring in cracks or crevices formed between two surfaces (made from the same metal, different metals or even a metal and a non-metal). This type of corrosion is initiated by the restricted entrance of oxygen from the air by diffusion into the crevice area leading to different concentrations of dissolved oxygen in the common electrolyte (the so-called aeration cell). Again, the two partial reactions take place on different parts of the surface. Oxygen reduction takes place in the outer areas with higher oxygen concentrations easily accessible by the surrounding air, whereas the anodic metal dissolution occurs in the crevice area resulting in localized attack (e.g. pitting). It can also occur under washers or gaskets, when the entry of water underneath is not prevented).
Crevice volume – It refers to any small, narrow, or restricted space between two intersecting surfaces where fluid can become trapped or restricted in its flow. In internal combustion engine design, it represents the total volume of clearance spaces within the combustion chamber where the fuel-air mixture cannot be easily reached by the flame front. In corrosion and material science, it defines the stagnant region where crevice corrosion is likely to occur. In hydraulic and pneumatic systems, it refers to the ‘dead volume’ or unswept areas within valves, pumps, and fittings.
CRI – CRI is the coke reactivity index. It is measured by a laboratory test designed to simulate the loss of coke through reaction in the reducing atmosphere, as the coke makes its way down the blast furnace. Coke is heated up to 950 deg C in an inert atmosphere and held at that temperature in an atmosphere of carbon di-oxide. The coke is cooled down under the inert atmosphere and the loss in weight expressed as a percentage is the coke reactivity index value of the coke. Coke reactivity index measures the ability of coke to withstand breakage at room temperature and reflects coke behaviour outside the blast furnace and in the upper part of the blast furnace.
Crib – It is a network of cast-iron bars or a grid used to support the upper mould (cope) when a traditional cope flask is omitted. It is also the cylindrical outer shell / wall of a sand mixing and mulling machine which contains the aggregate during blending.
Crimp – It is the waviness of a fibre or fabric, which determines the capacity of fibres to cohere under light pressure. It is measured by the number of crimps or waves per unit length.
Crimping -It is the forming of relatively small corrugations in order to set down and lock a seam, to create an arc in a strip of metal, or to reduce an existing arc or diameter.
C-ring stress corrosion test samples – It frequently referred to or typed phonetically as ‘C-ray’ or ‘C-ring’. These are ring-shaped metal samples used under constant strain to test an alloy’s susceptibility to stress-corrosion cracking (SCC).
C-ring test – It is a mechanical test which uses a ring-shaped sample with a small gap cut out of it (resembling the letter ‘C’) to evaluate material strength, brittleness, or stress-corrosion cracking.
C-ring test sample – It is a ring-shaped piece of material with a small section removed (resembling the letter ‘C’) which laboratories use to measure mechanical properties like hoop tensile strength, stress corrosion cracking, and fracture resistance under bending or compressive loads.
Crisis – It is an event which harms an organization, its facilities, its finances or its reputation within a short period of time. A crisis can occur as a result of an unpredictable event or as an unforeseeable consequence of some event that had been considered a potential risk. In either case, crisis almost invariably requires that decisions be made quickly to limit damage to the organization.
Crisis management – It is the application of strategies designed to help the organization deal with a sudden and significant negative event. Crisis management is the art of making decisions to head off or mitigate the effects of such an event, often while the event itself is unfolding. This frequently means making decisions under stress and without the support of key pieces of information.
Cristobalite – It is a rare, high-temperature mineral form of silica (SiO2) with the same chemical composition as quartz but a different crystal structure. It forms naturally in volcanic rocks or is produced industrially by heating quartz or silica sand to extreme temperatures (around 1,500 deg C).
Criteria – UNFC (United Nations Framework Classification for Resources) utilizes three fundamental criteria for reserve and resource classification namely (i) favourability of environmental-socio-economic conditions in establishing the viability of the project (E axis), (ii) maturity of technology, studies and commitments necessary to implement the project (F axis), and (iii) degree of confidence in the estimate of quantities of products from the project (G axis). These Criteria are each subdivided into categories and sub-categories, which are then combined in the form of classes or sub-classes. Criteria also consists of elements of quality standards which are expressed as compositions, properties, concentrations, levels, or narrative statements representing quality which supports a designated use of the material.
Criterion decision method – It refers to a methodology for assessing and ranking alternatives based on multiple, frequently conflicting criteria, effectively supporting decision-making processes. It involves structuring and solving decision problems by evaluating alternatives against specified criteria to improve transparency and decision quality.
Criterion function – In design optimization, it is the grouping of design parameters which are attempted to be maximized or minimized, subject to the problem constraints.
Criterion space – It is a representation where different objective functions are plotted along axes, allowing for the visualization of feasible objective function values corresponding to feasible design points in the design space. It is also referred to as cost space and illustrates the relationship between objective functions and constraints.
Critical – It is a medium containing a fissile nuclear material becomes critical when neutrons are produced (by the fission of this material) at the same rate as they disappear (through absorption and leakage to the outside). The point at which a nuclear chain reaction becomes self-sustaining.
Critical acceleration – It is the threshold acceleration needed to push a system, structure, or material from a stable state into a state of failure, sliding, or structural movement. It is the critical amplitude which governs the growth or decay of acceleration waves propagating into an unstrained region at rest, dependent on parameters such as acceleration wave velocity and the instantaneous moduli of the material.
Critical activities – These are the activities which are on the critical path.
Critical angle of attack – It is the angle at which airflow no longer streams smoothly over the upper surface of a blade, leading to a loss of lift.
Critical anodic current density – It is the maximum anodic current density observed in the active region for a metal or alloy electrode which shows active-passive behaviour in an environment.
Critical application – It is a software system or digital infrastructure whose failure, downtime, or compromise directly leads to catastrophic consequences, such as loss of life, severe physical damage, major legal / compliance violations, or extreme financial loss.
Critical appraisal – It is the systematic process of evaluating technical designs, literature, models, or research data to judge their validity, reliability, and practical relevance to a specific engineering problem. It translates to rigorous technical and methodological critique, separating verified physical principles and robust data from flawed assumptions, weak prototypes, or unverified scaling claims.
Critical buckling load – It is the maximum axial compressive force a structural member (such as a column, plate, or shell) can sustain before it loses stability, bends sideways, or collapses, frequently occurring at stress levels far below the material’s yield strength.
Critical buckling strain – It is the specific strain level at which a structural element, plate, shell, or member becomes susceptible to buckling, marking the threshold where structural stability is compromised under compressive or bending loads. It represents the onset of geometric instability rather than material yielding or crushing.
Critical capillary pressure – It is the minimum capillary pressure needed for a non-wetting fluid (such as oil or gas) to overcome interfacial tension and begin displacing a wetting fluid (such as water) inside the pores of a porous medium or foam lamellae.
Critical cell – It is a specific unit or element within a discretized cell complex, mesh, or topological space that cannot be paired or reduced away by local gradient flows or matchings.
Critical chip thickness – It is the maximum thickness of material which can be removed by an abrasive grain without initiating cracks or fracture, allowing for ductile-mode machining. It depends on material properties like Young’s modulus, Knoop hardness, and critical fracture toughness. It is also . the threshold uncut chip thickness below which a distinct shear-formed chip cannot form. If the chip thickness is below this critical value, the material does not shear. Instead, it undergoes elastic-plastic deformation, rubbing, and plowing against the tool’s cutting-edge radius.
Critical collapse pressure – It is the maximum external hydrostatic or lateral pressure a cylindrical structure (such as a pipe, well casing, or riser) can withstand before its cross-section permanently deforms inward, buckles, or caves in. It is the threshold pressure where compressive hoop stresses exceed the structural or material limits of the pipe, causing the shape to flatten or collapse into a multi-lobed or oval cross-section.
Critical component – It is a part, material, or sub-system whose failure or malfunction can lead to a direct safety hazard, system failure, or loss of core operational capability.
Critical compressive loading stress – It is frequently called critical buckling stress. It is the threshold value of compressive stress where a slender structural member loses its stability and suddenly bends or buckles sideways rather than simply crushing.
Critical concentration – It very frequently refers to the critical micelle concentration (CMC). It is the minimum concentration of a surfactant or amphiphilic polymer needed to trigger the spontaneous self-assembly of molecules into clusters called micelles.
Critical cooling rate – It is the minimum rate of continuous cooling for preventing undesirable transformations. For steel, unless otherwise specified, it is the slowest rate at which austenite can be cooled from above critical temperature to prevent its transformation above the martensite start temperature.
Critical crack tip opening displacement – It is the maximum physical separation (opening) between the opposite faces of a crack at its tip just before unstable fracture or crack propagation begins.
Critical crevice temperature – It is the lowest temperature at which crevice corrosion starts on a metal alloy in a specific environment, normally containing chlorides.
Critical current density – In an electrolytic process, it is a current density at which an abrupt change occurs in an operating variable or in the nature of an electrodeposit or electrode film.
Critical curve – In a binary or higher order phase diagram, it is a line along which the phases of a heterogeneous equilibrium become identical.
Critical damage – It is the threshold or state of material degradation, structural deformation, or micro-cracking at which a component or system loses its functional integrity, structural stability, or ability to resist further loading, leading to immediate failure, fracture, or the onset of rapid crack propagation.
Critical damage value – It is the specific threshold where a material or structure stops holding loads and begins to fracture or fail completely.
Critical damping – It is the minimum quantity of damping needed for a displaced system to return to its static equilibrium position in the shortest possible time without oscillating or overshooting.
Critical debonding – It refers to the threshold point or critical energy value at which a physical separation (debonding) begins to propagate between a bonded adhesive, coating, or reinforcement material and its underlying substrate. It is the critical energy release rate or stress limit at which the bond interface fails and a crack or separation actively grows rather than remaining stable.
Critical depth – It is the flow depth in an open channel where the specific energy is at a minimum for a given discharge. It is the flow depth at a section in an open channel where the flow is critical. It is used to classify the channel profile and to determine if the flow is sub-critical or super-critical based on whether the flow depth is higher or less than the critical depth, respectively.
Critical design review – It is a formal, multi-disciplined technical assessment which evaluates a near-complete product or system design to verify that it meets all functional and performance requirements.
Critical desorption pressure – It is frequently synonymous with the Langmuir pressure. It is the reservoir or equilibrium pressure at which an adsorbed gas begins to release from a solid matrix (such as coal or shale) into the free gas phase, specifically equal to the pressure at which half of the maximum adsorption capacity is reached.
Critical diagonal crack – It is a major inclined shear and flexural crack in a reinforced concrete beam or slab which leads directly to brittle, catastrophic structural failure.
Critical diameter – It is the diameter of the bar which can be fully hardened with 50 % martensite at its centre.
Critical dimension – It is a dimension on a part which is to be held within the specified tolerance for the part to function in its application. A non-critical tolerance can be for cost or weight savings or for manufacturing convenience, but is not essential for the products.
Critical disruptive voltage – It is the minimum phase-to-neutral voltage at which the air surrounding a power conductor becomes ionized (breaking down the dielectric strength of air) and a corona discharge begins.
Critical dose – It is the specific threshold quantity of radiation or energy absorbed by a material above which it undergoes severe, measurable, or irreversible structural changes.
Critical energy release rate – It is the threshold value of the energy release rate at which a crack begins to propagate unstably and cause fracture.
Critical equipment component – It a part, device, or sub-system whose failure leads to unacceptable safety hazards, environmental damage, major operational shutdowns, or regulatory non-compliance.
Critical equipment unit – It is an individual machine, device, system, or component whose failure directly or indirectly causes severe consequences to safety, environment, regulatory compliance, or core organizational production objectives.
Critical excitation – It is the worst-case input motion, such as an earthquake ground acceleration, which produces the maximum possible structural response (like peak displacement or stress) within a defined set of physical constraints or allowable energy limits.
Critical excitation method – It is an analytical approach used to find the worst-case ground motion which produces the maximum possible response (such as peak displacement, inter-story drift, or acceleration) in a given structure.
Critical excitation problem– It is the challenge of finding the worst-case input or ground motion (such as an earthquake) which causes the maximum possible response in a structure while respecting a defined set of physical or mathematical constraints.
Critical factors – These are the necessary, high-impact variables which dictate the final properties, structure, and performance of a metal or alloy. Modifying any of these factors fundamentally changes the material’s internal structure (micro-structure) and its mechanical behaviour.
Critical failure mode – It is a specific way a component or system can break-down which results in an immediate loss of core function, severe safety hazards, or catastrophic system collapse. It describes the exact physical or functional manner in which a part fails (such as a structural bridge support snapping or a server kernel panic) rather than why it failed.
Critical fibre length – It is the minimum fibre length needed for internal stress to reach the fibre’s breaking point, allowing the fibre to effectively reinforce a composite material.
Critical field – It is the maximum magnetic field strength a material can withstand while remaining in a super-conducting state. When the external magnetic field exceeds this threshold, the material loses its zero electrical resistance and expels the super-conducting state, reverting to a normal conducting state.
Critical flaw size – It is the size of a flaw (defect) in a structure which causes failure at a particular stress level.
Critical flow – It refers to a fluid flow condition where the mass flow rate reaches a maximum limit since further reductions in downstream pressure cannot propagate upstream.
Critical flow rate – It is the maximum flow rate which can be attained by a compressible fluid as it flows from a high-pressure region to a low-pressure region.
Critical flow velocity – In pipe flow, it is the maximum velocity at which a fluid can flow through a conduit while maintaining a smooth, streamlined (laminar) flow. It is also the flow velocity at which the corrosion rate of materials, such as steel, in sodium becomes constant after increasing with velocity; it varies based on factors like oxygen concentration and temperature, and has been reported to be around 3 meters per second to 7 meters per second.
Critical fracture – It refers to the point at which an existing crack or flaw in a material, transitions from stable (slow or controlled growth) to unstable (rapid, catastrophic propagation), causing sudden structural failure.
Critical fracture stress – It is the maximum principal stress at which a material fails or undergoes rapid crack propagation, particularly in notched or cracked structures. It is the threshold value of the maximum principal stress needed to initiate cleavage or brittle fracture in a material.
Critical frequency – It very frequently refers to the highest frequency of a radio wave which is reflected back to earth by an ionospheric layer when sent straight up at vertical incidence. The threshold where waves at or below the frequency bounce back, while higher frequencies pierce through into space.
Critical grain growth – It refers to the abnormal or excessive enlargement of specific grains when a lightly strained metal is heated to a high temperature, resulting in a coarse, uneven microstructure that severely reduces mechanical strength.
Critical heat flux – It refers to the maximum heat flux at which a surface can dissipate heat before transitioning to an unstable boiling regime, potentially leading to overheating. It is influenced by factors such as surface roughness and the number of nucleation sites. It is the maximum thermal limit in boiling heat transfer where a surface can dissipate heat before a sudden degradation occurs, leading to an unsafe and extreme rise in surface temperature.
Critical humidity – It is the relative humidity above which the atmospheric corrosion rate increases sharply for some metals.
Critical illumination – It is the formation of an image of the light source in the object field.
Critical infrastructure – It refers to the physical and digital systems, networks, and assets so important to the organization that their failure or destruction causes a debilitating impact on organizational working, and employees’ safety. Critical infrastructure integrates traditional information technology (IT) with operational technology (OT).
Criticality – It is a metric or state which measures how important an asset, function, or component is to a system’s safety, mission success, and operational continuity. In plant maintenance and reliability, criticality measures the level of risk associated with the failure of a machine, part, or infrastructure asset. Criticality evaluates what happens if the asset breaks down (costs, safety hazards, environmental damage, or production downtime). It evaluates how frequently the asset is expected to fail based on age and repair history. Engineers use a criticality analysis to rank equipment so they can spend money and time fixing high-risk items first.
Criticality analysis – It is a systematic risk-assessment process used to rank equipment, assets, or system components based on the potential impact and frequency of their failure.
Criticality level – It is a rating which shows how important an asset, machine, or system is to safety, operations, and organizational goals based on the risk and impact of its failure. There are three common criticality levels namely level-A / tier-1 (high criticality), level B / tier-2 (medium criticality), and level-C / tier-3 (low criticality).
Criticality review – It is a data-driven risk assessment process which evaluates and ranks equipment, assets, or system designs based on the severity and probability of their failure.
Critical kernel – It normally refers to the central, privileged core of an operating system or a mathematical / digital image processing structure which controls core resource execution and safety.
Critical layer thickness – It refers to the maximum thickness which a strained layer can achieve while maintaining its structural integrity without the formation of defects. For superlattices, each layer is required to have a thickness less than its own critical thickness, and the total thickness of the superlattice is also to be less than the critical thickness of the alloy with the same average composition. It is also the specific thickness (or radius) of thermal insulation applied to a cylindrical or spherical body up to which the rate of heat transfer actually increases rather than decreases.
Critical length – It is the minimum fibre length needed for shear loading to its ultimate strength by the matrix.
Critical level – It refers to a specific threshold, concentration, or operating point which is not to be exceeded to prevent system failure, structural collapse, or environmental damage.
Critical load – It is the maximum compressive force or weight a structural member can support before it loses stability and fails by buckling. It is also the maximum electrical demand a system can handle before it loses stability or fails.
Critical load for a column – It is the compressive load at which a slender structural column suddenly bends or buckles. It is determined or calculated by using the Euler buckling formula to determine the Critical load of a column.
Critical load for electrical power – It is the electrical power which is to be maintained for a vital function, such as an organization’s ability to operate. It is to be maintained during a power failure or powered down in an orderly manner to prevent system crashes, data corruption, and hardware damage. Critical loads are to be supplied with the electrical power which is of a high quality and reliability, and hence cannot be interrupted.
Critical load for pollution – It is a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur per the present knowledge.
Critical loading amplitude – It is the specific threshold of alternating stress or strain magnitude which triggers structural instability, plastic deformation, or rapid fatigue failure in a component.
Critical longitudinal stress – Applied to fibres, it is the longitudinal stress necessary to cause internal slippage and separation of a spun yarn. It is also the stress necessary to overcome the inter-fibre friction developed as a result of twist.
Critical Mach number – It is the free stream Mach number at which the flow over an airfoil reaches sonic speed (Mach 1) at some point on its surface, leading to decreased pressure and potential shock wave formation. Typically, this occurs around a Mach number of 0.7 during normal operating conditions.
Critical mass – It is the smallest quantity of fissile material needed to support a self-sustaining nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (e.g. the nuclear fission cross-section), its density, its shape, its enrichment, its purity, its temperature and its surroundings.
Critical mass fraction – It is the specific threshold proportion or ratio of a dispersed phase’s mass to the total mass of the system at which a phase inversion occurs, meaning the dispersed phase switches to become the continuous phase.
Critical micelle concentration – It is the concentration of a micelle at which the rate of increase of electrical conductance with increase in concentration levels off or proceeds at a much slower rate.
Critical micelle concentration – It is the minimum concentration of a surfactant needed to start forming micelles in a solution. It is the threshold where added surfactant molecules stop lowering surface tension and instead group together into clusters called micelles. Below this limit, single surfactant molecules (monomers) float freely or sit on surfaces. Above this limit, free monomer counts stay flat while extra molecules form micelles. It marks the exact point where building micelles becomes more energetically favorable than keeping free monomers in the liquid.
Critical moisture content – It is the specific moisture level in a material where the drying process transitions from a constant-rate period to a falling-rate period.
Critical oxygen concentration – It is the minimum dissolved oxygen concentration needed to sustain the maximum growth rate and metabolic activity of a microbial or cell culture without limiting respiration. It is the threshold oxygen concentration below which a mixture of flammable gas, vapour, or dust and air does not propagate a flame or explode, even in the presence of a strong ignition source.
Critical path – It is the sequence of activities which determines the longest path through the network that yields the minimum time in which an entire project can be completed. It is the path which has the longest length through the project. If the slack is zero for an activity, then it is on critical path. Similarly if slack is positive then the activity is not on the critical path.
Critical path method – It is an arrow diagram which is similar to a programme evolution review technique (PERT) network in terms of its construction technique. The rules for construction are very much the same. The major differences centre on (i) the usual omission of circles for events (and hence, the orientation toward activities), and (ii) the time estimate of the duration of the activity rather than the completion of an event. Critical path method is useful since it (i) provides a graphical view of the project, (ii) predicts the time needed to complete the project, and (iii) shows which activities are critical for maintaining the schedule and which are not. The limitations of critical path method are (i) while critical path method is easy to understand and use, it does not consider the time variations which can have a great impact on the completion time of a complex project, (ii) Critical path method has been developed for complex but fairly routine projects with minimum uncertainty in the project completion times, and (ii) for less routine projects there is more uncertainty in the completion times, and this uncertainty limits the usefulness of critical path method.
Critical period – It refers to a specific, high-stakes time interval where a system’s stability, capacity, or operational safety is most vulnerable and needs precise management.
Critical pigment volume concentration – It is the volume percent of pigment in a coating in which the pigment particles are surrounded by resin so that no free surface pigment exists.
Critical pitting potential – It is the lowest value of oxidizing potential at which pits nucleate and grow. It is dependent on the test method used.
Critical plane – It is the specific plane within a material or structural component which experiences the most extreme damage, stress, or strain accumulation, making it the main location where a fatigue crack nucleates and grows.
Critical plane approach – It refers to a methodology for assessing damage accumulation in materials, where damage is mainly considered to occur on planes aligned with maximum shear stress or normal to maximum principal stress, particularly in the context of fatigue failure.
Critical point – It is the temperature or pressure at which a change in crystal structure, phase, or physical properties occur. It is also termed as the transformation temperature. In an equilibrium diagram, critical point is that combination of composition, temperature, and pressure at which the phases of an inhomogeneous system are in equilibrium.
Critical point wetting – It is a term to describe a transition from partial wetting to complete wetting as a bulk critical point is approached. For example, when two liquids coexist within a miscibility gap with an external third phase like a gas or a solid wall, and are heated towards the critical point, both the difference between their interfacial energies with the third phase, as well as the energy of the liquid–liquid interface separating them, vanish. Since the difference between the interfacial energies of the two liquids with the third phase vanishes faster than the liquid–liquid interfacial energy, complete wetting of one of the two liquid in contact with the third phase on the other liquid arises before the bulk critical point is reached.
Critical pressure – It is that pressure above which the liquid and vapour states are no longer distinguishable.
Critical pressure coefficient – It is the specific value of the pressure coefficient at a point on an airfoil or body where the local fluid flow first reaches the speed of sound (Mach 1). It marks the exact pressure value corresponding to the critical Mach number, which is the free-stream Mach number where local sonic conditions are first attained on the surface (even though the plane or free-stream flow is still subsonic).
Critical quenching rate – It is the minimum mean cooling rate from the solution treatment temperature necessary to retain the alloying constituents in solid solution and hence permit the alloy to meet specified mechanical property requirements in the precipitation hardened (aged) condition.
Critical radiation level – It is the minimum radiation level which equates absorbed radiation to collector losses, resulting in zero useful energy.
Critical radius – It is the minimum particle size from which an aggregate is thermodynamically stable. In other words, it is the lowest radius formed by atoms or molecules clustering together (in a gas, liquid, or solid matrix) before a new phase inclusion (a bubble, a droplet or a solid particle) is viable and begins to grow. Formation of such stable nuclei is called nucleation.
Critical rake angle – It is the rake angle at which the action of a V-point tool changes from cutting to plowing.
Critical raw materials – Critical raw materials are materials or substances used in the primary production or manufacturing of goods. Critical raw materials are raw materials which are economically and strategically important for the economy but have a high-risk associated with their supply.
Critical resolved shear stress – It is the shear stress which is necessary to initiate slip on a particular slip system in a grain. Resolved shear stress (RSS) is the shear component of an applied tensile or compressive stress resolved in the slip direction on a slip plane which is neither perpendicular nor parallel to the stress axis.
Critical response – It refers to the maximum or worst-case structural, mechanical, or dynamic behaviour a system experiences under a specific set of critical loading, environmental, or operational conditions (such as peak earthquake ground motion, impact loads, or limit/bifurcation points).
Critical Reynolds – It refers to the range of Reynolds numbers (between 2 × 10 to the power 5 and 5 × 10 to the power 5) where a substantial drop in the drag coefficient is observed, indicating a transition in flow characteristics around a cylinder.
Critical Reynolds number – It is the specific value of the dimensionless Reynolds number at which a fluid flow transitions from a smooth, orderly laminar flow to a chaotic, irregular turbulent flow.
Critical section – It is the specific cross-section of a structural member or foundation where internal forces (such as bending moment, shear force, or torsion) reach their maximum design demand, or where a specific design check governs safety. It is also a segment of code where a process or thread accesses shared resources, such as memory, variables, files, or hardware devices, which are not to be concurrently accessed by more than one execution path at a time.
Critical shear stress – It is the shear stress needed to cause slip in a designated slip direction on a given slip plane. It is called the critical resolved shear stress if the shear stress is induced by tensile or compressive forces acting on the crystal. It is the threshold point where an applied shear force causes a material, soil bed, or fluid to transition from a stable state to failure, movement, or permanent deformation.
Critical speed map – It is a graphical plot which shows how the undamped natural frequencies (critical speeds) of a rotating shaft or rotor system change as a function of support or bearing stiffness.
Critical state – It is the ultimate condition where a material (like soil or granular media) undergoes continuous shearing or distortion at a constant volume and constant effective stress.
Critical state line – It is a unique locus of points representing the ultimate state where a soil or granular material undergoes continuous shearing at a constant volume (constant void ratio or specific volume) and constant effective stress, flowing like a frictional fluid.
Critical state soil mechanics – It is a theoretical framework which describes how soils continuously deform at a constant volume, constant effective stress, and constant shear stress when subjected to continuous shearing.
Critical state theory – It defines the ultimate condition where a soil or granular material undergoes continuous shearing and deforming as a frictional fluid without any further changes in volume or effective stress.
Critical strain – In mechanical testing, it is the strain at the yield point. It is also the strain just sufficient to cause recrystallization, since the strain is small (normally only a few percent), recrystallization takes place from only a few nuclei, which produces a recrystallized structure consisting of very large grains.
Critical strain energy release rate (G1c) – It is a material property which quantifies the energy needed to initiate and propagate a crack in a material under Mode I loading conditions (tensile separation). Essentially, it is the energy per unit area which needs to be dissipated for the crack to grow.
Critical stress – It is the specific threshold value of internal force per unit area which triggers a definitive structural or microstructural failure, such as yielding, buckling, or fracture. Since ‘critical stress’ depends on the mode of failure, engineers look at several specific definitions depending on the application:
Critical stress-intensity factor (K1c) – It also known as plane strain fracture toughness. It is a material property which represents the resistance of a material to crack propagation under specific loading conditions. It is the maximum stress intensity factor a material can withstand before a crack starts to grow. Essentially, it is the threshold stress intensity which a material can handle before fracture occurs in a plane strain condition. It is a scaling factor used in linear-elastic fracture mechanics to describe the intensification of applied stress at the tip of a crack of known size and shape.
Critical sub-station – It refers specifically to a high-priority, vital transfer or control point whose failure, damage, or removal severely disrupts grid stability, isolate major generating stations, or trigger cascading black-outs across regional inter-connections.
Critical surface – In a ternary or higher order phase diagram, it is the area upon which the phases in equilibrium become identical.
Critical surface tension – It is the threshold surface tension of a liquid below which the liquid completely spread out on a given solid surface with a contact angle of zero.
Critical task – It is an activity or function which is to be performed correctly and on time, since any failure, error, or delay are going to directly cause project failure, system failure, or serious harm. Critical tasks is an activity with zero slack or float time. If a critical task is delayed by even a single day, the final completion date of the entire project is delayed by the same quantity. These sequential tasks form the project’s ‘critical path’ which dictates the absolute minimum time needed to finish a project. Critical tasks are also an action tied to human performance or system functions which prevents major accidents, environmental disasters, or loss of life.
Critical technology – It refers to a foundational or high-risk system, component, or scientific application essential for project success, or operational performance.
Critical technology element – It is a new or novel technology component which a system or platform depends on to succeed. If the technology fails or is delayed, the entire system cannot meet its operational requirements or schedule.
Critical temperature – It is that temperature above which the vapour phase cannot be condensed to liquid by an increase in pressure. It is synonymous with critical point if pressure is constant.
Critical temperature of brittleness – It is frequently called the ductile-to-brittle transition temperature (DBTT) or simply the brittleness temperature. It is the specific threshold where a material shifts from ductile (bending or deforming before breaking) to brittle (shattering or cracking suddenly under stress).
Critical temperature range – It is synonymous with transformation ranges, which is the preferred term. Transformation ranges are those ranges of temperature within which austenite forms during heating and transforms during cooling. The two ranges are distinct, sometimes overlapping but never coinciding. The limiting temperatures of the ranges depend on the composition of the alloy and on the rate of change of temperature, particularly during cooling.
Critical thickness – It is the maximum thickness a strained crystalline film or alloy can reach before it relaxes and forms structural defects (like misfit dislocations) to relieve stored mechanical strain energy.
Critical thickness of insulation – It is the specific thickness of an insulating material around a cylindrical or spherical object (like a pipe or electrical wire) at which the rate of heat transfer is maximized and total thermal resistance is minimized.
Critical value – It refers to a specific threshold or limit of a material property, operational parameter, or system response where a distinct physical change, structural failure, or phase transition occurs.
Critical voltage – It is the essential voltage value needed to initiate and form nano-fibres during electro-spinning, where higher voltages lead to smaller fibre diameters because of increased charge repulsion, but excessive voltage can cause jet instability and poor fibre morphology.
Critical volume – It is the volume occupied by one mole of a substance (or a unit mass) at its critical temperature and critical pressure. It is the critical molar volume which relates to molecular, typically represented in models such as the van der Waals formalism, where it is fixed to three times the covolume value.
Critical wall thickness – It is minimum wall thickness calculated from pressure design equations needed to safely withstand internal design pressure without yielding or bursting.
Critical wave-length – In electromagnetics and telecommunications, it is the free-space wave-length corresponding to the critical frequency (the maximum frequency of a wave which can be reflected back by an ionospheric layer or cut off in a wave-guide). It is calculated by dividing the speed of light by the critical frequency in hertz. In semi-conductors and optics.it is the cutoff wave-length related to the band-gap energy of a material, beyond which light absorption becomes negligible. In the photoelectric effect, it is the maximum wave-length of light capable of ejecting photoelectrons from a metal surface. In ocean and hydro-elastic engineering, it is a threshold wave-length determined by water depth and structure characteristics. Waves shorter than this critical value invert in shape (flattened crests and peaked troughs), while longer waves stay elevated with peaked crests. In optical and UV (ultra violet) protection engineering: It defines the wavelength below which 90 % of the total integrated absorbance / optical density curve (from 290 nano-meters to 400 nano-meters) resides, used to rate the ‘broad-spectrum’ performance of materials like sunscreens (frequently needing 370 nano-meters and higher).
Critical wave number – It is the specific spatial frequency or wave number at the threshold of instability, such as the onset of buckling, hydrodynamic instability, or fluid-flow transition.
Critic network – It is a neural network which predicts the value of a given state, typically utilizing a linear activation function at the last layer to provide flexibility in the range of state values it can output.
Cronbach’s alpha coefficient – It is a coefficient of consistency which measures how well a set of variables or items measures a single, unidimensional, latent construct in a scale or inventory. Alpha scores are conventionally interpreted as (i) high – 0.9, (ii) medium – 0.7 to 0.89, and (iii) low – 0.55 to 0.69.
Croning process – In casting, it is a shell moulding process which uses a phenolic resin binder. Sometimes it is referred to as C-process or Chronizing. In the process, dry, free-flowing moulding material, consisting of resin coated sand is added by means of gravity or by application of pressure onto or into the tool.
Crop – It is an end portion of an ingot, slab, or bloom which is cut off as scrap. It is also means to shear a bar or billet.
Crop and cobble shear – It is used in hot rolling mills is to crop front end, tail end, as well as to segment cutting in case of eventualities. These shears are normally of start / stop type and are driven either with flywheel mounted pneumatic clutch / brake or with direct current motor driven. These shears are controlled through programmable logic control system and provide very close tolerance of the cut length.
Cropping – It refers to the shearing or cutting process used to trim excess material, bars, or plates to a specific size or shape.
Cropping shear – It is also called crop shear. It is a heavy-duty industrial machine used to cut off the irregular, defective, or out-of-tolerance head and tail ends of hot or cold metal strips, bars, and plates.
Cross – It is a pipe fitting. It has one inlet and three outlets, or vice versa and like tees come in equal and reducing forms. A cross is more expensive than two tees but has the advantage of reduced space and needs less manpower to install.
Cross-angle configuration – It refers to a design set-up where two structural members, fluid vectors, gear axes, or material properties intersect at a non-parallel angle (frequently 90-degree or a specific skew) to optimize strength, motion, or fluid dynamics.
Crossbar – It is a horizontal structural or electrical component which connects vertical posts, lines, or circuits in a grid.
Crossbar or arm conveyor – This type of conveyor consists of a single or two strands of endless chain, to which are attached spaced, removable or fixed arms (or cross members) from which materials are hung or festooned. The arms can be replaced by shelves / trays to support packages or objects to carry them in a vertical or an inclined path. Special arms are designed to suit specific load configuration. Depending on the design of arms, they are called by different names, some of which are (i) pendent conveyor, (ii) pocket conveyor, (iii) wire mesh deck conveyor, (iv) removable crossbar conveyor, (v) fixed cross-bar (or arm) conveyor, and (vi) swing tray conveyor.
Crossbar switch – It is a matrix of electronic or mechanical switches connecting multiple inputs to multiple outputs. It allows any input to connect to any output at the same time. This set-up creates a direct path for data or signals without blocking other transfers.
Cross belt magnet – It is a device which is used for removing ferrous materials from the conveyor belt, demanding routine checks to uphold its proper functioning.
Cross bracing – It is a system which utilized to reinforce building structures in which diagonal supports intersect. Cross bracing is normally seen with two diagonal supports placed in an X-shaped manner. Under lateral force (such as wind or seismic activity) one brace is under tension while the other is being compressed. In steel construction, steel cables be used because of their high resistance to tension (although they cannot take any load in compression). The common uses for cross bracing include bridge (side) supports, along with structural foundations. This method of construction maximizes the weight of the load a structure is able to support. It is a normal application when constructing earthquake-safe buildings. In belt conveyors, it is diagonally positioned rods and turn-buckles across roller bed or live roller conveyors, improving frame squareness crucial for precise tracking.
Cross breaks – It is same as coil breaks. Cross breaks are creases or ridges in sheet or strip which appear as parallel lines across the direction of rolling and which normally extend the full width of the sheet or strip.
Cross-correlation – It is a mathematical measure of similarity between two different signals or data series as a function of the relative time displacement (lag) applied to one of them.
Cross-correlation coefficient – It is a normalized statistical and signal-processing measure which quantifies how closely two different time-series signals or functions resemble each other as one is shifted in time relative to the other. It scales the standard cross-correlation value, typically bound between -1 and +1 (or 0 and 1 depending on the normalization method), so a person can compare the shape and timing similarity of signals regardless of differences in their overall amplitude or energy.
Cross-correlation function – It measures the similarity between two different signals (or random processes) as a function of a relative time shift or lag. It is frequently described as a sliding dot product or sliding inner-product used to find how well a reference signal matches a time-shifted version of another signal.
Cross-correlation method – It is a mathematical method which measures how similar two signals or data sets are when one is shifted in time relative to the other.
Cross-correlation technique – It is a mathematical method used to measure how similar two different signals or data series are when one is shifted relative to the other.
Cross-country rolling mill – It is a rolling mill in which the mill stands are so arranged that their tables are parallel with a transfer (or crossover) table connecting them. Such a mill is used for rolling structural shapes, rails, and any special form of bar stock not rolled in the ordinary bar mill.
Cross-coupling – It refers to the phenomenon where an action, force, signal, or motion in one axis, system, or circuit inadvertently creates an unwanted effect or response in another orthogonal or adjacent axis, system, or circuit.
Cross direction – It is a direction or plane perpendicular to the direction of working. In rolled plate or sheet, the direction across the width is frequently called long transverse, while the direction through the thickness is called short transverse.
Crossed polars – It refers to a technique which utilizes two linear polarizing filters positioned at 90-degree to each other, allowing for the examination of samples, such as plastics, to visualize patterns of colour indicating birefringence and variations in thickness.
Cross-flow – It refers to a fluid movement where the main flow travels sideways or perpendicularly relative to a surface, filter, or another fluid stream.
Cross-flow filtration – It is also known as tangential flow filtration. It is a filtration technique where the feed solution flows tangentially across the surface of a membrane. This method uses a pressure differential to drive smaller components through the membrane pores, while larger particles are retained and can be recycled. An electric field can be applied to improve membrane performance.
Cross-flow separation – It is a filtration process where the feed stream approaches the membrane tangentially, creating a peripheral flow that minimizes membrane plugging by dislodging particulates, resulting in two product streams namely permeate, which passes through the membrane, and retentate, which contains the rejected solutes and suspended solids.
Cross forging – It is the preliminary working of forging stock in flat dies to develop mechanical properties, particularly in the centre portions of heavy sections.
Cross-functional team – It is a team whose members are from several units of the organization which interface with, and need input from, one another.
Cross-gain modulation – It is an optical effect in semi-conductor optical amplifiers where one high-power light signal changes the gain of the amplifier, which then modulates the intensity of a second lower-power light signal.
Cross hardening – It refers to an increase in a metal’s yield stress when the direction of the applied load changes orthogonally (at a 90-degree angle) relative to the initial loading path. It is a specific type of work hardening which occurs during complex, multi-axis metal forming operations.
Cross hatching – it is a macroscopic effect of numerous surface tears, transverse to the rolling direction, which can occur when the entry angle into the cold mill work rolls is large.
Cross-head – It is a sliding block or bar which connects a piston rod to a connecting rod in reciprocating engines and pumps.
Cross-head displacement – It is the physical travel or movement of the moving clamp (crosshead) in a materials testing or tensile machine. It measures the change in distance between the clamping fixtures (grips) as a test frame pulls, compresses, or bends a sample.
Cross helical gears – This type of gear is recommended only for a narrow range of applications where loads are relatively light. Since contact between teeth is a point instead of a line, the resulting high sliding loads between the teeth requires extensive lubrication. Hence, very little power can be transmitted with cross helical gears.
Cross laminate – It is a laminate in which some of the layers of material are oriented approximately at right angles to the remaining layers with respect to the grain, or strongest direction in tension.
Crossland criterion – It is a high-cycle multiaxial fatigue failure model used to predict the fatigue limit of metallic components under complex cyclic loading.
Cross lay – In wire ropes, the cross lay is referred to as the point contact lay, as each wire is in contact with each other. The laying of the wires is carried out in such a way that the lay angle is almost equal for each layer of wire of the same diameter. The length of the wires in each layer is also to be the same and the wires of each layer are in contact with each other. Hence, the tension stress which works on the wire becomes uniform, but the bending stress due to the contact points is added and so the fatigue resistance is not as great.
Cross-layer design – It is a network architecture approach which allows communication, coordination, and resource sharing across non-adjacent layers of a protocol stack, breaking away from traditional strict layering.
Crosslink – It is a chemical bond or small sequence of bonds which connects one adjacent polymer chain to another. Crosslink also refers to the connections between adjacent polymer chains in a crosslinked polymer, forming a three-dimensional network structure, typically through covalent bonding. These connections are often permanent and contribute to the polymer’s thermoset properties.
Cross-linked poly-ethylene – It is a modified form of high-density poly-ethylene (HDPE) which has undergone a chemical or physical reaction resulting in a three-dimensional molecular structure with improved resistance to high temperature and pressure. It is mainly used in tubing applications and can be produced through methods such as the per-oxide method, silane method, and radiation method.
Cross-linked polymer – It is a polymer in which adjacent linear molecular chains are joined at different positions by covalent bonds. Cross-linked polymer is formed by chemical bonds between polymer chains, which improves its mechanical properties, heat resistance, and chemical stability. This process is necessary in the production of different materials, including vulcanized rubber, epoxy resins, and structural components.
Cross-linker – It is a type of monomer used in polymerization reactions to create chemical bonds between polymer chains, resulting in cross-linked or network polymers which possess improved strength, rigidity, and resistance to heat and chemicals.
Cross-linking – With thermosetting and certain thermoplastic polymers, the setting up of chemical links between the molecular chains. When extensive, as in majority of the thermosetting resins, cross linking makes an infusible supermolecule of all the chains. In rubbers, the cross linking is just enough to join all molecules into a network.
Cross-linking agent – It is a substance which promotes or regulates chemical or physical links between polymer chains, turning them into a connected 3D network rather than a collection of separate strands.
Cross-linking, degree of – It is the fraction of cross- linked polymeric units in the entire system.
Cross-linking density – It is the number of permanent crosslink junctions (covalent or strong physical bonds) per unit volume or mass in a polymer network.
Cross-linking point – It refers to the specific chemical bond, ionic interaction, or physical junction where two or more individual polymer chains are tied together.
Cross-over – It is a concise conveyor section inserted when the drive switches to the opposite side, distinct from conveyor crossover structures designed for personnel crossing, needing precise installation considerations. Cross-over is also an intersection or track arrangement on railway lines (such as a scissor cross-over) which lets trains safely switch or move from one track to another for traffic management, maintenance, or emergencies. Cross-over is also an electronic circuit or network which splits an audio signal into different frequency bands and routes them to the appropriate speaker drivers (such as low frequencies to a sub-woofer / woofer and high frequencies to a tweeter)
Cross-over distortion – It is a non-linear wave-form defect which occurs in push-pull Class B and Class AB amplifier output stages when the signal transitions, or crosses over, from one active switching device (such as an n-p-n / p-n-p transistor pair) to the other.
Cross-over region – It is the frequency range where signals are divided among different drive units to ensure each unit operates within its intended frequency limits, preventing degradation of sound quality and potential physical damage.
Cross-over sub – It is a specialized coupling used to connect pipes with different thread types, ensuring proper alignment and functionality in a string of pipes. It is important to have dedicated cross-over subs for each needed connection to prevent potential failures because of the improper threading or installation practices.
Cross-over walk-ways – These walkways made of steel structure are used for personnel crossing over areas of dangerous nature such as rolling mill roller table, belt conveyors and similar hazardous areas.
Cross-permeation phenomenon – It refers to the unintended, diffusive transport of product gases, specifically hydrogen (H2) and oxygen (O2), through a polymeric or solid membrane (such as a proton exchange membrane, or PEM) in electro-chemical devices like water electrolyzers.
Cross-phase modulation – It is a nonlinear optical effect in fibre-optic communication where the optical phase of one light beam is altered by the intensity of a second, co-propagating beam sharing the same medium.
Cross-ply laminate – It is a laminate with plies normally oriented at 0-degree and 90-degree only. It is also a filamentary laminate which is not uniaxial.
Cross-power spectral density – It is a mathematical function which describes how the power or energy of two different signals (x(t) and y(t)) is distributed across the frequency domain.
Cross rail – It is a horizontal structural member on a machine tool (such as a milling machine, planer, or vertical boring mill) which spans across the upright columns. It is also the fixed assembly at the intersection of two railway tracks where one rail runs out and leaves a physical gap for wheel flanges to pass.
Cross range – It refers to the distance or resolution measured perpendicular to the line of sight (range direction). It refers to the resolution aspect in synthetic aperture processing which indicates the ability to distinguish between different targets located at different angles relative to the antenna, which can degrade based on the division of the Doppler bandwidth into multiple sub-bands for image formation.
Cross range resolution – It is a radar system’s ability to distinguish between two targets located at the same distance (range) from the radar, but separated by an angle in the direction perpendicular (cross-range) to the antenna axis.
Cross ribs – These are intersecting or transverse structural ridges added to a component or slab to distribute loads, prevent warping, and increase rigidity.
Cross rolling – It is rolling of metal or sheet or plate so that the direction of rolling is around 90-degree from the direction of a previous rolling. The cross-rolling mode is characterized by the fact that the axis of the rolled product is parallel with the rolls-axes. The rolls are rotating in the same direction. The rolling stock is rotating in the direction of acting the resulting friction forces, i.e. in the opposite direction than is the direction of work rolls. This mode of rolling is used for the production of shafts or for rolling of grinding balls etc.
Cross-rolling mill – It is a specialized metal-forming machine where the axes of the rotating work rolls are set at an inclined cross angle relative to each other rather than being strictly parallel.
Cross-rolling process – It is a metal-forming process where a work-piece is rolled by changing the rolling direction, typically by 45-degree to 90-degree, relative to previous passes to refine the grain structure and improve mechanical properties. It can also refer to cross-wedge rolling, a rotary technique which uses opposing wedge-shaped tools to shape cylindrical billets into stepped parts.
Cross section – In technical drawing a cross-section, being a projection of an object onto a plane that intersects it, is a common tool used to depict the internal arrangement of a 3-dimensional object in two dimensions. It is traditionally cross-hatched with the style of cross-hatching frequently indicating the types of materials being used.
Cross sectional area – It is the area measured at right angles to the molten metal flow stream at any specified portion of the gating system.
Cross sectional contour – It refers to the line of intersection of a beam reference surface with a plane orthogonal to the beam axis, which describes the shape of the beam’s cross-section. It is the line of intersection formed where a plane cuts orthogonally (at a 90-degree angle) through a beam’s reference axis or a 3D structural component. It is a profile or side view of the ground surface created by taking levels along a line running perpendicular to a main baseline or linear project (such as a road, rail line, or canal).
Cross section analysis – It is the evaluation of a 3D structural member’s geometry, material composition, and stress distribution by examining a 2D slice or plane cut through it.
Cross section drawing – Cross-section drawing allows the engineer look at the different components of an object vertically. This 2-dimensional (2-D) drawing is helpful to provide an overview of both the visible and hidden components of the object.
Cross section constant – It is a design feature where the geometric profile and cross-sectional area of a structural member (such as a beam, rod, rail, or pipe) remain uniform and unchanged along its entire longitudinal axis. It is effective probability parameters which quantify the likelihood of a specific nuclear interaction, such as neutron absorption, fission, or scattering, per unit path length or per target nucleus inside a reactor core.
Cross-slip – It is a process where a screw dislocation shifts from one glide plane to an intersecting slip plane.
Cross-spectral density – It measures how the power and phase relationship between two different signals or random processes are distributed across the frequency. It is the integral of the cross-correlation function between two measurements, representing the frequency domain relationship between them. It is used to analyze the output of linear time-invariant systems and to assess the coherence between signals.
Cross-talk – It is interference from other communication channels, which can occur through capacitive or inductive coupling, imprecise timing, or insufficient discrimination between signals. It is classified into near-end and far-end types, and can be intelligible or unintelligible, affecting the error margin in transmission lines.
Cross tee – It is also known as a cross fitting or four-way fitting. It is a four-outlet industrial or plumbing pipe fitting shaped like a plus sign (+) that connects four pipes at 90-degree angles to split, merge, or redirect fluid or gas flow.
Cross-validation technique – It is a statistical and data-resampling technique used in engineering and machine learning to evaluate how well a predictive model or algorithm generalizes to an independent, unseen dataset. Instead of relying on a single train-test split (which can be heavily influenced by how the data is partitioned), cross-validation repeatedly divides the available dataset into multiple training and testing subsets, trains the model on a portion of the data, and validates it on the remaining portion.
Cross-wind – It refers to wind which blows perpendicular to the direction of travel or flow, which can considerably impact the performance of structures such as cooling towers in engineering applications, particularly affecting their thermos-hydraulic performance.
Cross-wire weld – It is a weld made at the junction between crossed wires or bars.
Cross-wise direction – Cross-wise refers to the cutting of samples and to the application of load. For rods and tubes, cross-wise is any direction perpendicular to the long axis. For other shapes or materials which are stronger in one direction than in another, cross-wise is the direction which is weaker. For materials which are equally strong in both directions, cross-wise is an arbitrarily designated direction at right angles to the length-wise direction.
Crowding-out – It refers to a situation where one resource, component, process, or project displaces or eliminates another due to physical, spatial, computational, or budgetary constraints.
Crown – It refers to the highest middle point or convex upward curve of a surface, structure, or mechanical part, designed to shed water, resist deflection under load, or transmit motion. It is the top roof or arched ceiling of the furnace’s combustion or melting chamber. It handles extreme radiant heat and helps direct thermal energy back down toward the materials inside. It is also the upper part (head) of a forming press frame. On hydraulic presses, the crown normally contains the cylinder. On mechanical presses, the crown contains the drive mechanism. In rolls, it is a shape (crown) ground into a flat roll for ensuring flatness of cold-rolled and hot-rolled sheets and strips. It is also a contour on a sheet or roll where the thickness or diameter increases from edge to centre. In metalworking and rolling mills, a crown is the slight convex contour or thickness variation where a rolled metal strip or mill roll is thicker (or has a larger diameter) in the middle than at its edges.
Crown block – It is the stationary set of pulleys, or sheaves, mounted at the very top of a drilling rig’s derrick or mast.
Crowned pulley – A pulley uniquely tapering equally from both ends toward the centre, with the highest diameter at the midpoint. It is a pulley system tapering at both ends and dipping in the middle to aid belt tracking, featuring periodic checks for effectiveness.
Crowned roll – It refers to a roll where the diameter at the centre is larger than the diameter at the ends. This non-cylindrical shape is designed to help compensate for deflection under load, ensuring a more even pressure distribution and preventing uneven rolling or flatting of the material being processed.
Crown glass -it is a type of optical glass characterized by a low refractive index (around 1.52) and low chromatic dispersion (high Abbe number typically between 50 and 85). It is traditionally made from alkali-lime silicates with potassium oxide. Modern variants include borosilicate crown glasses.
Crowning – It is the deliberate shaping of conveyor pulleys to facilitate belt tracking and prevent misalignment, necessitating regular assessments for ongoing effectiveness.
Crown sheet – In a fire-box boiler, it is the plate forming the top of the furnace.
Crow’s feet – These are also called pick-up. These are particles which have been torn out within the die opening and have bonded to the tool. They produce grooves in the surface. They continue to grow until the shear force exerted by the extrusion is sufficient to tear them away and to carry them out with the extruded section.
Crushed recycled concrete aggregate – It is a sustainable construction material produced by crushing, screening, and cleaning old, demolished concrete structures (such as buildings, roads, and bridges) into granular fragments.
Crucible – It is a vessel or pot, made of a refractory substance or of a metal with a high melting point, used for melting metals or other substances.
Crucible furnace – It is a melting or holding furnace in which the molten metal is contained in a pot-shaped (hemispherical) shell. Electric heaters or fuel-fired burners outside the shell generate the heat which passes through the shell (crucible) to the molten metal.
Crucible melting process – It is a method where metals or other materials are placed inside a specialized, high-temperature container (a crucible) and heated until molten for casting, alloying, or refining.
Crucible swelling number – It is a method for determining the swelling properties of hard coal when heated in a covered crucible. It is the size index of the coke button produced when 1 gram of -0.212 millimeters coal is heated under specified conditions, as compared with a set of standard profiles. The degree of swelling is expressed in numbers of 1 to 9 based on cross-sectional area profiles of the swollen sample which are convenient linear units. International Organization for Standardization standard ISO 501 describes the procedure for this test.
Crucible tongs – These are specialized scissor-like metal tools designed to safely grasp, lift, and transfer extremely hot crucibles, flasks, and evaporating dishes in engineering, metallurgy, and laboratory settings. These are built with a scissor or pivot joint, featuring two long metal arms and curved, forked, or serrated pincers that match the contour of a crucible.
Crucible zone – It is also called the hearth or well. In a vertical melting furnace like a cupola or blast furnace, it is the lowest chamber or cavity at the base where liquid metal and slag collect and pool between periodic taps.
Cruciform sample – It is a cross-shaped test piece used in material mechanics and structural engineering to evaluate how materials behave under complex, multi-axial (biaxial or triaxial) in-plane loads. It resembles a plus sign (+) with a central test (gauge) region and four orthogonal arms.
Crude benzol – Benzol (also known as benzole) recovered from coke oven gas is called as crude benzol. It contains small quantities of a large number of impurities which consists of the unsaturated and sulphur compounds. These impurities have negative effects on the organic processes. Benzol is the name normally applied in the chemical industry to a mixture of hydrocarbons of the benzene series, in which benzene itself predominates, in association with certain of its homologues and various impurities.
Crude methanol – It is a mixture of methanol, water, dissolved gases, and by-products produced during the synthesis of methanol from syngas. It undergoes purification to achieve the desired purity for different applications.
Crude oil – It is a naturally occurring, unrefined petroleum liquid found in underground geological formations and porous rock reservoirs.
Crude oil distillation – it is the initial process in oil refining which separates crude oil into different fractions through atmospheric and vacuum distillation, providing qualified feed for downstream processing units. This process involves physical changes where heated crude oil is fractionated based on boiling points.
Crude oil system – It refers to the integrated network of equipment, piping, and chemical processes used to extract, separate, treat, transport, and refine raw petroleum from underground reservoirs into usable products.
Crude ore – Crude Ore means all ores, metals, minerals and other products containing mineral substances mined for removal from the mine site, which have not been subject to further processing or concentrating. It is also called run-of-mine ore.
Crude source – It refers to raw, unrefined petroleum or hydro-carbon-laden material extracted from natural underground or underwater reservoirs.
Crude steel – Crude steel is the term used for the first solid steel product which is produced during the solidification of liquid steel in a steel melting shop. Crude steel is part of saleable steel when it is supplied to customers for its use or for further processing. Crude steel is normally processed into finished steel either by rolling or by forging processes.
Crude tar – It is also known as coal tar. It is the by-product generated during the high temperature carbonizing of coking coal for the production of the metallurgical coke in the by-product coke ovens. It is a black, viscous, sometimes semi-solid, fluid of peculiar smell, which is condensed together with aqueous ‘gas-liquor’ (ammoniacal liquor), when the volatile products of the carbonization of coking coal are cooled down. It is acidic in nature and is water insoluble. It is composed primarily of a complex mixture of condensed-ring aromatic hydrocarbons. It can contain phenolic compounds, aromatic nitrogen (N2) bases and their alkyl derivatives, and paraffinic and olefinic hydro-carbons.
Crumbling – It is a general descriptor rather than a single, formal technical term. It typically refers to the gradual disintegration, fragmenting, or breaking apart of a material or structure into smaller pieces because of the mechanical stress, environmental degradation, or aging. Depending on the specific field of engineering, the phenomenon of crumbling is mapped to precise technical terms, properties, and material failures. When concrete, masonry, or stone crumbles, engineers use specific failure term such as spalling, delamination, and efflorescence and sub-florescence. In materials engineering, the tendency of a solid to crumble under load is defined by its mechanical properties such as brittleness, and friability. In soil mechanics, it is termed as soil crumbling.
Crumb rubber – It is the ground rubber fragments of the size of sand or silt which is used in rubber or plastic products, or processed further into reclaimed rubber or asphalt products.
Crumple zone – It is an outer structural safety feature of a vehicle engineered to deform in a controlled manner during a collision to absorb kinetic energy and reduce the peak deceleration force transmitted to the passenger cabin.
Crush – It is buckling or breaking of a section of a casting mould because of incorrect register when the mould is closed. It is an indentation in the surface of a casting because of the displacement of sand when the mould is closed. It is also the permanent localized compressive deformation. Also, it is the spalling of (normally thin) surface treated cases on gears because of the overload. This is also known as case crushing. In a split-journal bearing, it is the quantity by which a bearing half extends above the horizontal split of the bore before it is assembled
Crusher – A crusher is a multi-dimensional machine which is designed to reduce large size materials into smaller size materials. Crushers can be used to reduce the size, or change the form of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in the case of ore), so that pieces of different composition can be differentiated for separation.
Crush forming – It is shaping a grinding wheel by forcing a rotating metal roll into its face so as to reproduce the desired contour.
Crushing – It is the process of transferring a force amplified by mechanical advantage through a material made of molecules which bond together more strongly, and resist deformation more, than those in the material being crushed do.
Crushing chamber – It is the enclosed cavity or space inside a crushing machine where raw materials (such as rocks, ores, or aggregates) are subjected to mechanical forces, such as compression, impact, or attrition, to reduce their size. It is the functional heart of a crusher where size reduction and mineral liberation take place.
Crushing circuit – It is an integrated system of crushers, vibrating screens, feeders, and conveyor belts which works together to break down raw mined ore or rock into a specific, controlled particle size for downstream processes like grinding, leaching, or separation.
Crushing devices – These devices hold material between two parallel or tangent solid surfaces, and apply sufficient force to bring the surfaces together to generate enough energy within the material being crushed so that its molecules separate from (fracturing), or change alignment in relation to (deformation), each other.
Crushing plant – It is an integrated industrial facility or mobile installation which uses a series of mechanical equipment to break down large rocks, ores, concrete, or demolition waste into smaller, uniform construction aggregates or process-ready mineral particles.
Crushing resistance – It is the ability of a material or structural component to withstand compressive loads, vertical pressure, or crushing forces without fracturing, deforming, or breaking apart. It measures a material’s maximum limit under compression before a structural or material failure occurs.
Crushing strain – It is the critical compressive strain at which a material or structural component permanently fails, crushes, or buckles under excessive compressive or localized contact loads. It represents the limit of compressive deformation a material can handle before structural collapse, kinking, micro-buckling, or crushing occurs.
Crushing stress – It is the localized compressive stress which develops in a material when two bodies press against each other under a compressive load. Unlike general compressive stress distributed across a full cross-section, crushing stress acts specifically over the projected contact area between mating surfaces.
Crushing test – It is a radial compressive test applied to tubing, sintered-metal bearings, or other similar products for determining radial crushing strength (maximum load in compression). It is also an axial compressive test for determining quality of tubing, such as soundness of weld in welded tubing.
Crush strip or bead – It is an indentation in the parting line of a pattern plate which ensures that cope and drag have good contact by producing a ridge of sand which crushes against the other surface of the mould or core.
Cryo-compressed hydrogen – It is an advanced physical hydrogen storage method which merges cryogenic cooling (low temperatures) and high-pressure compression into a single system.
Cryo-compression – It is an energy storage method which combines liquid and compressed gas states at cryogenic temperatures (typically below -150 deg C or 120 Kelvin).
Cryogel – It is a super-macroporous polymer network synthesized by freezing a precursor solution (such as a monomer, polymer, or colloidal dispersion) so that ice crystals act as templating agents, followed by thawing or freeze-drying.
Cryogenic air separation plant – The cryogenic air separation plant utilizes difference in boiling points of gases for their separation. It is based on the fact that the different constituent gasses of air have different boiling points and by manipulating the immediate environment in terms of temperature and pressure, the air can be separated into its components. The boiling point of oxygen at a 0.1 MPa pressure and 0 deg C is minus 182.9 deg C and that at 0.6 MPa pressure and 0 deg C is minus 160.7 deg C. The corresponding boiling points of nitrogen are minus 195.8 deg C and minus 176.6 deg C, and those for argon are minus 185.8 deg C and minus 164.6 deg C respectively. Cryogenic separation of air into its constituent gases involves various processes. Combination of these processes are needed in a cryogenic air separation plant, of which the fundamental ones are (i) air compression, (ii) air purification, (iii) heat exchanging, (iv) distillation, and (v) product compression. Cryogenic separation is most effective process when any of the three criteria need to be met namely (i) high purity oxygen is needed (higher than 99.5 %), (ii) high volumes of oxygen are needed (greater than 100 tons of oxygen / day), or (iii) high pressure oxygen is needed.
Cryogenic cooling – It is the application of high-velocity jets of cryogenic agents, such as liquid nitrogen or liquid carbon di-oxide, to rapidly cool the cutting zone during machining. This method improves machining surface integrity and tool life while maintaining an eco-friendly environment. It is the process of reaching and maintaining extremely low temperatures—typically below -150 deg C (123 K), using liquefied gases like nitrogen or helium, or mechanical refrigerators.
Cryogenic cycle – It is a thermodynamic refrigeration or liquefaction process designed to produce and maintain ultra-low temperatures, typically below 120 Kelvin (−153 deg C).
Cryogenic distillation – It is a gas separation process which cools gas mixtures to extremely low (cryogenic) temperatures until they liquefy, then separates the components based on their different boiling points.
Cryogenic energy storage – It is frequently referred to as liquid air energy storage (LAES). It is a mechanical and thermal energy storage system which uses liquefied gases (such as air or nitrogen) stored at extremely low temperatures below -150 deg C as the storage and working medium.
Cryogenic hydrogen – It refers to hydrogen which is cooled and maintained at extreme low temperatures, typically around 20 Kelvin (-253 deg C), where it transitions into a liquid state or a high-density cold gaseous / super-critical state.
Cryogenic separation – It is a physical process which separates components from a gas mixture by cooling the mixture to ultra-low (cryogenic) temperatures, typically below -73 deg C to -150 deg C or lower (173 Kelvin–203 Kelvin), and utilizing differences in their boiling points, vapour pressures, and volatilities.
Cryogenic service – It refers to any application, process, or fluid system which handles materials, equipment, or liquids at extremely low temperatures, typically below -150 deg C (123 K), though some definitions or codes start at -73 deg C or -160 deg C.
Cryogenic tank – It is a specialized, double-walled, vacuum-insulated pressure vessel engineered to store and transport liquefied gases at extremely low temperatures, typically below -150 deg C or 120 Kelvin. It features an inner vessel (normally made of low-temperature-resistant austenitic stainless steel) to hold the fluid, surrounded by an outer carbon steel or stainless-steel shell.
Cryogenic temperature – It normally refers to extremely low temperatures below −150°C (123 Kelvin) extending down to absolute zero (0 K or −273.15 deg C). Some technical standards and engineering applications define the threshold slightly differently, such as below 120 K (−153.15 deg C) or fluids with a normal boiling point below 0.1 mega-pascal boiling temperature under 120 K.
Cryogenic tensile testing – It is a destructive mechanical test which pulls a material sample until it fractures while exposing it to ultra-low temperatures, typically below −150 deg C down to absolute zero, using liquefied gases like nitrogen or helium.
Cryogenic testing – It evaluates the performance, mechanical properties, and structural integrity of materials and components at extremely low temperatures, typically below −150 deg C or 123 Kelvin. Engineers use cooling media like liquid nitrogen (−196 deg C) or liquid helium (−269 deg C) to simulate operational environments found in liquefied natural gas (LNG) systems, and hydrogen energy tech.
Cryogenic treatment – A cryogenic treatment is the process of treating work-pieces to cryogenic temperatures (typically around -184 deg C, or as low as −190 deg C) in order to remove residual stresses and improve wear resistance in steels and other metal alloys, such as aluminum. In addition to seeking enhanced stress relief and stabilization, or wear resistance, cryogenic treatment is also sought for its ability to improve corrosion resistance by precipitating micro-fine eta carbides, which can be measured before and after in a part using a quantimet.
Cryogenic toughness – It is a material’s ability to absorb energy and resist brittle fracture at very low temperatures, typically below −150 deg C (123 Kelvin) down to absolute zero.
Cryogenic valve – It is a valve which is capable of functioning at cryogenic temperatures
Cryolite – it is a rare, ice-like mineral with the chemical formula Na3AlF6 (sodium hexa-fluoro-aluminate) which is mainly used as a flux to lower the melting point of alumina during aluminum extraction.
Cryo-preservation – It is the process of cooling materials to ultra-low sub-zero temperatures, typically around −80 deg C to −196 deg C using liquid nitrogen, to halt all physical, and chemical activities, placing the sample into suspended animation for long-term storage.
Cryo-pump – It is a type of vacuum pump which relies on the condensation of gas molecules and atoms on internal surfaces of the pump, which are maintained at extremely low temperatures.
Cryo-SEM – It means cryogenic scanning electron microscopy. It is an advanced imaging technique where hydrated, liquid, or heat-sensitive samples are rapidly frozen and imaged at ultra-low temperatures inside a vacuum chamber. It is a technique for imaging samples in a frozen preserved state, which prevents out-gassing and structural collapse during high-vacuum conditions. This method involves flash freezing samples in liquid nitrogen and allows for the examination of internal structures by fracturing the frozen sample before imaging.
Cryostat – It is a specialized device used to maintain extremely low (cryogenic) temperatures, typically ranging from -150 deg C to absolute zero, to house and test samples or sensitive equipment.
Crypto-crystalline – It refers to a texture of rocks, such as basalt, characterized by mineral grains which are too small to be seen with the naked eye, resulting in a fine-grained or vitreous appearance.
Cryptographic hash – It is a function which maps bit sequences of arbitrary length to fixed-size outputs, called digests, while ensuring properties such as computational ease of calculation, preimage resistance (difficulty in finding the original input from the output), and collision resistance (difficulty in finding two different inputs that produce the same output). It is a deterministic mathematical algorithm which converts an input of arbitrary data size into a fixed-length string of bits or characters, known as a hash value or digest.
Cryptography – It is the practice and study of techniques for securing communication and information through the use of codes, ensuring the confidentiality and integrity of data during processes such as authentication.
Crystal – It is a solid composed of atoms, ions, or molecules arranged in a pattern which is repetitive in three dimensions. It is also that form, or particle, or piece of a substance in which its atoms are distributed in one specific orderly geometrical array, called a ‘lattice’, essentially throughout the crystals directions.
Crystal analysis – It is a method for determining crystal structure, e.g., the size and shape of the unit cell and the location of all atoms within the unit cell.
Crystal cutting – It is a specialized machining and slicing process for single-crystal materials (such as quartz, silicon, or synthetic crystals) where the material removal, chip formation, and mechanical behavior depend heavily on the internal crystallographic orientation.
Crystal density – It is the mass per unit volume of a crystalline material, calculated directly from the mass of the atoms in a unit cell and the volume of that unit cell.
Crystal detector – It is an early solid-state electronic component which rectifies an alternating current radio or microwave signal into a direct current (DC) or low-frequency audio signal.
Crystal diamond tool – It is an ultra-precision cutting or machining instrument made from either a natural or synthetic single-crystal diamond.
Crystal dislocation – It is a one-dimensional (linear) defect in a crystal lattice where the periodic arrangement of atoms is disrupted.
Crystal face – It refers to a distinct, flat (planar) exterior surface of a crystal which reflects its internal, repeating atomic arrangement.
Crystal field – It is the static electric field produced by surrounding charge distributions (such as ions, anions, or polar ligands) which breaks the degeneracy of electron orbital states, specifically ‘d’ or ‘f’ orbitals, in transition metal or rare-earth centres.
Crystal-figure etching – It is the discontinuity in etching depending on crystal orientation. Distinctive sectional figures form at polished surfaces. It is closely related to dislocation etching.
Crystal filter – It is an electronic circuit which uses the mechanical resonance of piezoelectric crystals, normally quartz, to select a specific narrow band of frequencies while rejecting all others.
Crystal grain – It is an individual small crystal region within a solid polycrystalline material, such as a metal, ceramic, or semi-conductor, where the atoms share a continuous, uniform crystallographic orientation.
Crystal growth – it is the phase in crystallization where solute atoms, ions, or molecules deposit and systematically integrate onto a pre-existing crystalline nucleus or seed to expand its size.
Crystal growth rate – It is the rate of change in a characteristic dimension of a crystal, the linear advance rate of an individual crystal face, or the rate of change in mass of a crystal or population of crystals, with expressions varying based on measurement methods and crystal geometry.
Crystal lattice – It is a repeating three-dimensional pattern of points which shows how atoms, ions, or molecules are arranged inside a crystalline solid like salt or diamond. Each point stands for a particle, and repeating the smallest basic block, called a unit cell, builds the whole crystal structure.
Crystal length – It the physical dimension or thickness of a scintillation crystal element along the path of incoming radiation. A longer crystal length improves the efficiency of detecting coincidence photons, though it can reduce light collection and increase photon scattering. It is also the axial length (such as edge lengths ‘a’;, ‘b’, ‘c’) of a unit cell’s principal axes in a crystal lattice. These lengths are fundamental lattice parameters used to describe the symmetry and periodic structure of a material. Crystal length is also the characteristic length or mean size of ordered crystalline domains within a material (frequently measured via X-ray diffraction or Scherrer’s equation), or the grain size in a polycrystalline sample.
Crystalline – It is that form of a substance which comprises pre-dominantly (one or more) crystals, as opposed to glassy or amorphous. It refers to a solid material whose constituent atoms, ions, or molecules are arranged in a highly ordered, repeating three-dimensional pattern called a crystal lattice which extends over long distances.
Crystalline alloy – It is a metallic material made by combining a base metal with one or more additional elements, where the atoms are arranged in a regular, repeating, periodic 3D crystal lattice structure.
Crystalline anisotropy – It refers to the directional dependence of a material’s properties, particularly in relation to its magnetic characteristics, which can be quantified through magneto-crystalline anisotropy energies (MAE). These energies are typically small and challenging to calculate, often approximated as differences in band structure energies between different magnetization directions.
Crystalline coating – It very frequently refers to a sub-surface chemical treatment applied to concrete which reacts with moisture and unhydrated cement particles to grow insoluble, needle-like crystals within its capillary tracts, voids, and micro-cracks. Unlike traditional barriers which sit on top of a surface, a crystalline coating penetrates deeply into the concrete matrix, turning the concrete itself into an impermeable water barrier.
Crystalline defects – These are the deviations from a perfect three-dimensional atomic packing which are responsible for much of the structure-sensitive properties of the materials. Crystal defects can be point-defects (dislocations) or surface defects (vacancies), line defects (dislocations), or surface defects (grain boundaries).
Crystalline density – It is the mass per unit volume of a crystalline material, where a denser structure indicates shorter atomic distances which can improve reaction rates, such as detonation velocity in energetic materials. Higher crystal density is also associated with reduced free space in the crystal lattice, which can lower impact sensitivity. It is also the mass of a crystalline substance divided by the volume of its crystal unit cell.
Crystalline fracture – It is a pattern of brightly reflecting crystal facets on the fracture surface of a poly-crystalline metal, resulting from cleavage fracture of several individual crystals.
Crystalline network – It us also called crystal network. It is a structured, repeating three-dimensional arrangement of atoms, ions, or molecules linked together by periodic chemical bonds.
Crystalline organization – It refers to the specific packing order or arrangement of atoms within a crystalline material, determined by the chemical composition and features of the constituent atoms, which influences the overall stability and properties of the crystal. This arrangement is typically represented by a unit cell, which serves as the fundamental building block for crystal growth.
Crystalline phase – It refers to a solid state of matter where atoms, ions, or molecules are arranged in a highly ordered, repeating three-dimensional pattern known as a crystal lattice. It refers to the distinct structural arrangement of atoms within a material, which can be identified through techniques such as X-ray diffraction (XRD) which analyze the patterns of diffracted X-rays to reveal the crystalline structure formed during synthesis.
Crystalline plastic – It is a polymeric material having an internal structure in which the atoms are arranged in an orderly three-dimensional configuration.
Crystalline quality – It is a measure of how closely a solid material’s atomic arrangement matches an idealized, periodic crystal lattice, evaluated mainly through diffraction resolution and mosaic spread (microscopic block misalignment).
Crystalline region – It refers to a localized area within a solid material, such as a semi-crystalline polymer or a polycrystalline metal, where atoms, ions, molecules, or polymer chains are arranged in a regular, periodic, and repeating three-dimensional pattern.
Crystalline semi-conductor material – It is a solid material with a well-ordered, repeating atomic arrangement (a crystal lattice) whose electrical conductivity falls between that of a conductor and an insulator.
Crystalline silica – It is a common mineral found in the earth’s crust. It is made of silicon and oxygen atoms arranged in a repeating, ordered crystal lattice (SiO2). Materials like sand, stone, concrete, and mortar contain crystalline silica. It is also used to make products such as glass, pottery, ceramics, bricks, and artificial stone.
Crystalline silicon – It is a form of silicon characterized by a repeating, long-range ordered atomic lattice structure (cubic diamond structure), used as the main semi-conducting material in electronics and photovoltaic cells.
Crystalline silicone – It is a form of silicon characterized by a rigid, repeating, and long-range ordered atomic lattice (specifically a cubic diamond structure).
Crystalline silicon (Si) module – It is a solar photovoltaic (PV) assembly made of individual crystalline silicon solar cells connected electrically, encapsulated between a transparent front glass and a protective back-sheet, and framed for mechanical and environmental durability.
Crystalline silicon solar cell – It is a semiconductor photovoltaic device which converts sunlight directly into direct current (DC) electricity using high-purity crystalline silicon as the light-absorbing material.
Crystalline state – It is a structural arrangement of matter where atoms, ions, or molecules are organized in a repeating, periodic, long-range three-dimensional order.
Crystallinity – the degree of structural order in a solid material, describing how closely its atoms, ions, or molecules arrange into a repeating, regular pattern. It is the degree of long-range structural order within a solid material, characterized by the presence of a crystal lattice which can extend in three dimensions or be limited to one or two dimensions. It considerably influences the physical and chemical properties of solid-state materials. For polymers, it is the state wherein a periodic and repeating atomic arrangement is achieved by molecular chain alignment.
Crystallite – It is a crystalline grain not bounded by habit planes.
Crystallite size – It is the mean size of a coherent, uninterrupted single-crystal domain within a material. It represents the region of a solid that scatters X-rays coherently as a single crystal.
Crystallization – it is the separation, normally from a liquid phase on cooling, of a solid crystalline phase. It is also the progressive process in which crystals are first nucleated (started) and then grown in size within a host medium which supplies their atoms. The host can be gas, liquid, or of another crystalline form.
Crystallization temperature – It is the temperature at which a material changes from a disordered or molten state into a highly ordered, repeating crystal lattice structure.
Crystallize – It refers to the process of forming a stable crystal structure through an initial nucleation step, followed by crystal growth, often facilitated by a nucleating agent or impurity.
Crystallized moisture – It is the chemically combined with the mineral matters in coal. It is also called decomposition moisture and is the water which is formed during thermal decomposition of the coal.
Crystallizer – It is a special die with water-cooled structure for rapid solidification of molten metal and used for continuous or semi-continuous casting, suction casting, and electroslag melting and casting.
Crystallographic anisotropy – It is the directional dependence of a material’s physical or mechanical properties based on the specific crystallographic orientation of its crystal lattice.
Crystallographic misorientation – It is the rotational difference or angular mismatch between the crystal lattice orientations of two distinct grains or crystallites in a polycrystalline material. It is the mathematical transformation or rotation needed to align the atomic coordinate system of one crystal lattice with the lattice of an adjacent crystal.
Crystallographic orientation – It is the specific spatial alignment of a crystal lattice inside a material compared to a fixed sample or laboratory coordinate system. It describes how the atoms, planes, and axes of a single crystal or individual grain are rotated relative to an external reference frame.
Crystallographic quality – It measures how closely a material’s internal atomic arrangement matches a perfect, defect-free crystal lattice. It is defined by two criteria namely resolution, which quantifies the limit of diffraction, and mosaic spread or mosaicity, which measures the misalignment of microscopic blocks in a crystal. It is critical for determining the level of detail in the electron density map and the accuracy of the structural model.
Crystallographic shear – It is the atomic-scale displacement or sliding of planes of atoms over one another along specific preferred crystallographic directions within a crystal lattice.
Crystallographic slip – It is the process by which a crystal accommodates macroscopic shape changes through atomic rearrangements along specific crystallographic planes and directions, known as slip planes and slip directions, respectively. This mechanism is related to the motion of dislocations within the crystal structure, allowing for plastic deformation while conserving the crystal’s integrity.
Crystallographic texture – It is the statistical preference or non-random distribution of crystal grain orientations within a poly-crystalline material.
Crystallographic texture measurement and analysis – It is an important tool in correlating the properties of a material to its micro-structural features. It can be performed on any pol-crystalline material. Poly-crystalline materials consist of several small crystals, or grains, separated by thin boundaries assembled compactly in an aggregate. The individual crystals, or crystallites, are relatively free of defects compared to the boundary structure. Hence, a complete description of a poly-crystal is complex. On a scale of the size of the crystallites (around 1 micrometer to 1 millimeter), at least the shape, volume, and crystallographic orientation of each grain are to be prescribed. In a tensile sample of typical dimensions, up to 10 to the power 10 grains can need characterization. There is also to be an internal structure in each grain on a much finer scale (around 1 nanometer to 100 nanometer), including second phases, dislocation tangles, and point defects. These structural features also affect material behaviour considerably. Hence, complete structural characterization of the poly-crystalline body is not feasible.
Crystal orientation – It is an arrangement in space of the axes of the lattice of a crystal with respect to a chosen reference or coordinate system. It is defined by the plane (Miller) indices of the lattice plane of a crystal. In observation of an electron microscope image using a TEM(transmission electron microscope), the particular crystal orientation (normally, orientation expressed by the low-order indices) is aligned to the direction of the incident electron beam.
Crystal originated particle – It is a small, pit-like surface or bulk defect in single-crystal silicon wafers, typically shaped as a sub-micron octahedral void, which forms because if the agglomeration of vacancies during the cooling phase of Czochralski (CZ) crystal growth.
Crystal oscillator – It is an electronic circuit which uses the mechanical resonance of a vibrating piezoelectric material, very frequently quartz, to generate an electrical signal with a very precise and stable frequency.
Crystal phase transformation – It is a process in which a solid crystalline material changes its internal atomic arrangement (crystal structure) and physical properties in response to changes in temperature, pressure, or composition, without necessarily changing its chemical makeup.
Crystal planes – These planes are families of parallel planes extending through a crystal, denoted by curved parentheses (hkl), where the indices indicate the plane’s orientation relative to the crystallographic axes. These planes can show identical arrangements of atoms and are categorized by their symmetry, frequently represented as {hkl}.
Crystal plasticity – It is a mesoscale computational technique which takes into account crystallographic anisotropy in modelling the mechanical behaviour of poly-crystalline materials. The technique has typically been used to study deformation through the process of slip, however, there are some flavours of crystal plasticity which can incorporate other deformation mechanisms like twinning and phase transformations. Crystal plasticity is used to get the relationship between stress and strain which also captures the underlying physics at the crystal level. Hence, it can be used to predict not just the stress-strain response of a material, but also the texture evolution, micro-mechanical field distributions, and regions of strain localization. The two widely used formulations of crystal plasticity are the one based on the finite element method known as crystal-plasticity finite element method (CPFEM), which is developed based on the finite strain formulation for the mechanics, and a spectral formulation which is more computationally efficient because of the fast Fourier transform, but is based on the small strain formulation for the mechanics.
Crystal-plasticity finite element method – It is a computational technique which is used to simulate the mechanical behaviour of crystalline materials, particularly focusing on the deformation processes at the microstructural level. It combines the principles of crystal plasticity theory with the finite element method (FEM) to model how stresses and strains are distributed within single crystals and poly-crystalline materials.
Crystal plasticity finite element modelling – It is an advanced computational method which combines crystal plasticity theory with the finite element method to simulate the mechanical behaviour and permanent deformation of crystalline materials at the microstructural level.
Crystal plasticity model – It is an approach which incorporates mechanical anisotropy into continuum models to simulate the mechanical behaviour of metallic materials, applicable at time and length scales relevant for engineering.
Crystal plate – It is a precision-cut piece of a single-crystal material (very frequently quartz) shaped along specific crystallographic axes, designed to mechanically resonate at a characteristic frequency when exposed to an alternating electrical voltage.
Crystal pulling – It is also known as pulling from the melt. The process extracts a single crystal ingot (boule) by slowly lifting a oriented seed crystal out of a high-temperature liquid melt.
Crystal size – It is the mean size of the ordered (crystalline) domains in a material, frequently corresponding to the coherent volume associated with a diffraction peak or the size of grains in a powder sample. It can be determined using the Scherrer’s equation, which relates crystal size to different parameters including X-ray wavelength and peak width at full width at half maximum (FWHM).
Crystal size distribution – It is the statistical representation of the relative abundance, number, or mass of crystals across different size intervals in a sample. It expresses how crystal populations vary in size (frequently measured as equivalent sphere diameters). Crystal size distribution (CSD) the number or mass of crystals per unit volume within defined size intervals, which influences crystallization processes and end-use applications. It can be expressed as a density distribution, indicating the number or mass of particles within specific size ranges.
Crystal structure – It is the arrangement of the atoms or molecules in the interior of a crystal. The unit cell of a crystal is the smallest pattern of the arrangement which can be contained in a parallelepiped, the edges of which form the ‘a’, ‘b’, and ‘c’ axes of the crystal. The three-dimensional aggregation of the unit cells in the crystal forms a space lattice, or Bravais lattice’.
Crystal system – It consists of seven groups into which all crystals can be divided. These groups are named triclinic, monoclinic, orthorhombic, hexagonal, rhombohedral, tetragonal, and cubic.
Crystal twinning – It occurs when two or more adjacent crystals of the same mineral are oriented so that they share some of the same crystal lattice points in a symmetrical manner. The result is an inter-growth of two separate crystals that are tightly bonded to each other. The surface along which the lattice points are shared in twinned crystals is called a composition surface or twin plane.
C-scan – It is the back-and-forth scanning of a sample with ultrasonics. It is a non-destructive testing technique for finding voids, delaminations, defects in fibre distribution, and so forth.
CSP technology – CSP means concentrated solar power or concentrating solar-thermal power. It is a technology which uses mirrors or lenses to focus a large area of direct sunlight onto a small receiver, converting optical energy into high-temperature thermal energy to generate electricity or supply industrial heat. Im this technology arrays of mirrors (heliostats, parabolic troughs, or linear reflectors) track the sun and reflect solar radiation onto a central receiver. CSP technology also means compact strip production technology. It produces hot strip in a single manufacturing line which combines casting, heating, and rolling.
CSR – CSR means coke strength after reaction. It gives indication of the strength of coke after being exposed to the reducing atmosphere of the blast furnace. Coke, after exposure to the high temperature and carbon di-oxide atmosphere of the coke reactivity test, is subjected to a tumbler test to determine the coke strength after reaction. Coke strength after reaction (CSR) measures the potential of the coke to break into smaller size under a high temperature carbon mono-oxide / carbon di-oxide environment which exists throughout the lower two-thirds of the blast furnace. CSR also means corporate social responsibility which means that organizations are to integrate social, ethical, and environmental impacts into their designs, operations, and decision-making processes. Instead of focusing solely on technical performance and cost-efficiency, CSR (corporate social responsibility) ensures that projects benefit local communities, protect natural resources, and uphold safety standards.
C-stage – It is the final stage in the reaction of certain thermosetting resins in which the material is practically insoluble and infusible. It is sometimes referred to as resite. The resin in a fully cured thermoset moulding is in this stage.
C-type alloy – It refers to a high-performance nickel-chromium-molybdenum (Ni-Cr-Mo) superalloy designed for extreme corrosion resistance.
Cube – It is a symmetrical three-dimensional geometric solid defined by six identical square faces, twelve equal-length edges, and eight vertices, with all adjacent faces meeting at right angles (90-degree).
Cube root – It is a value which, when multiplied by itself three times (cubed), yields the original number (y x y x y) = x. It is the direct opposite of cubing a number (a × a × a = a-cube).
Cube texture – It is a texture found in wrought metals in the cubic system in which nearly all the crystal grains have a plane of the type (100) parallel or nearly parallel of the plane of working and a direction of the type [001] parallel or nearly parallel to the direction of elongation.
Cube orientation -It refers to a specific crystallographic grain alignment where the crystal axes are parallel to the working or rolling axes of the material. It is expressed as {001}<100>, meaning the {001} crystal planes lie parallel to the rolling plane, and the <100> crystal directions are parallel to the rolling direction. It is a prominent recrystallization texture component. During cold rolling, it is considered kinematically metastable (sitting at a saddle point in the orientation space), meaning small mechanical perturbations can cause the crystal lattice to rotate.
Cubic – It means having three mutually perpendicular axes of equal length. It normally refers to something having three dimensions, a shape like a cube, or relating to the third power or degree. In crystallography, cubic specifically denotes a crystal system where the unit cell has the shape of a cube.
Cubic anisotropy – It is the directional dependence of physical properties (such as magnetic or mechanical behaviour) in materials which possess a cubic crystal symmetry.
Cubic Bezier curve – It is a parametric third-degree polynomial curve defined by four control points (P0, P1, P2, P3) which models smooth, continuous shapes in computer-aided design (CAD), and path generation.
Cubic boron nitride – It is a synthetic superhard material made of boron and nitrogen atoms arranged in a crystal lattice, ranking second only to diamond in hardness. Cubic boron nitride (CBN) is important for high-precision machining and material removal. Unlike diamond, which reacts chemically with iron at high temperatures, cubic boron nitride is chemically inert when used on iron and steel.
Cubic boron nitride grinding wheel – It is a high-performance industrial tool made with a synthetic super-abrasive rim used for precision grinding of hard ferrous metals.
Cubic decimeter – It is an International System of Units (SI) derived unit of volume equal to a cube with sides of 1 decimeter (10 centimeter), which is 1 litre or 1,000 cubic centimeters.
Cubic equation – It is a third-degree polynomial equation of the standard form ‘ax-cube + bx-square + cx + d = 0’, where ‘a’ is not equal to zero. It is used to model physical phenomena involving volumetric power, non-linear states, and three-dimensional behaviour.
Cubic meter – It is the International System of Units (SI) standard unit of volume, defined as the volume of a cube with edges that are exactly one meter in length (1 meter × 1 meter × 1 meter).
Cubic polynomial – It is an algebraic expression of degree three, written in the standard form f(x) = ax-cube + bx-square + cx + d = 0, where ‘a’, ‘b’, ‘c’, and ‘d’ are constants and ‘a’ is not equal to zero.
Cubic plane – It is a plane perpendicular to any one of the three crystallographic axes of the cubic (isometric) system, the Miller indices are {100}.
Cubic spline – It is a piecewise cubic polynomial whose coefficients change in different portions of a data set as per the specific rules, allowing for a smoothed curve to connect each data point.
Cubic spline curve – It is a piecewise third-order polynomial function which connects a series of data or control points with a smooth, continuous curve.
Cubic symmetry – It refers to a crystal lattice or 3D geometric structure which possesses the symmetrical properties of a cube, defined by three equal-length crystallographic axes which intersect each other at right angles (90-deg).
Cubic unit cell – It is the smallest repeating structural block of a crystal lattice which has a cubic shape (90-degree angles and equal edge lengths). When stacked in three dimensions, these identical units build up the entire crystal structure of a solid.
Cu–Cl cycle – It is copper-chlorine cycle. It is a multi-step thermo-chemical and hybrid process used to produce hydrogen (H2) by splitting water ‘H2O = H2 + 1/2 O2’. Instead of using high-temperature, single-step thermal decomposition (which needs extreme heat above 2,000 deg C), the Cu–Cl cycle uses a series of lower-temperature chemical and electro-chemical reactions, typically a 4-step configuration, where copper and chlorine compounds react in a closed loop and are completely recycled.
Cu component – It refers to the copper species involved in the copper−chlorine cycle, which is integral to hydrogen production and includes different various forms such as copper(I) chloride (CuCl) and copper(II) oxide (CuO). Its management presents challenges because of its reactivity and issues related to solid handling and transport within the cycle.
Cu films – These are thin layers of copper used in interconnect materials for ultra large scale integration technology, where they are deposited through processes such as physical vapour deposition and electro-chemical deposition to improve conductivity and electro-migration resistance.
Cuk converter – It is a negative-output capacitive energy fly-back DC–DC (direct current-direct current) converter which utilizes a capacitor for energy storage and power transfer, producing an inverted output voltage relative to the input. It is an advanced form of the buck–boost converter, capable of delivering ripple-free output and is suitable for various applications, including renewable energy systems.
Cullender and Smith method – It is a widely used numerical technique for calculating the flowing or static bottomhole pressure (BHP) in gas wells based on wellhead observations. Engineers rely on this method since it does not make simplifying assumptions about the variation of temperature or the gas compressibility factor (z-factor) along the depth of the wellbore. This makes it highly accurate for deep wells with variable temperature gradients and high-pressure environments.
Cullet – It is crushed, recycled, or broken glass used as a raw material addition in the production of new glass products.
Cullet glass – It is crushed or broken scrap glass which is processed and added to raw batch materials to manufacture new glass products. It accelerates melting. Cullet glass melts at a lower temperature than virgin raw materials like silica sand, soda ash, and limestone.
Culvert – It is a tunnel structure constructed under roadways or railways to provide cross drainage or to take electrical or other cables from one side to other. It is totally enclosed by soil or ground. Pipe culvert, box culvert and arch culvert are the common types used under roadways and railways.
Culvert pipe – It is heavy gauge, galvanized steel which is spiral-formed or riveted into corrugated pipe, or concrete pipe which is used for highway drainage applications.
Cumulants – These are a set of statistical values which that describe the shape, scale, and properties of a probability distribution, serving as an alternative to standard moments. These are formally defined as the coefficients in the Taylor series expansion of the cumulant-generating function K(t), which is the natural logarithm of the moment-generating function M(t).
Cumulative damage – In fatigue loading, it is a measure of damage, as expressed as a fraction of life to failure, as it accumulates with the number of cycles. When the stress level is changed, the life is changed. Hence, damage accumulates as per the stress level and number of cycles spent at a given stress. The most common (but not only) model for linear cumulative damage is the Palmgren-Miner cumulative damage model [D = Sigma(ni/Ni)]. In this equation, ‘ni’ is the number of load cycles spent at a stress for which the life is ‘Ni’. Failure is assumed to occur when the damage summation becomes unity.
Cumulative distribution – It is a function which calculates the probability that the values of a continuous random variable fall between specified values. It is defined as the integral of the probability density function from negative infinity to a given value.
Cumulative distribution function – It is a frequency distribution arranged to give the number of observations which are less than given values. 100 % of the observations are to be less than the largest class interval of the observations. In the context of mineral resource estimation and geology, it defines the probability that a random rock sample or ore block has a mineral grade less than or equal to a specific value ‘x’.
Cumulative effects – These are the changes to the environment, health, social and economic conditions as a result of a project’s residual effects combined with the existence of other past, present and reasonably foreseeable physical activities.
Cumulative energy demand system – System cumulative energy demand (CED) is the total quantity of primary energy consumed throughout the life cycle of a product or service, encompassing all stages from resource extraction to end-of-life.
Cumulative erosion-time curve – It is a graph of cumulative erosion against cumulative exposure duration, normally got by periodic interruption of the erosion test and weighing of the sample. This is the primary record of an erosion test used to derive other characteristics such as incubation period, maximum erosion rate, terminal erosion rate, and the erosion rate-time curve.
Cumulative failure rate – It is the total fraction or percentage of a population of systems, components, or devices which have failed by a given time (t), measured from the start of operation. It represents the cumulative distribution function (CDF) of time-to-failure, meaning it tracks total failures accumulated up to time ‘t’ divided by the total number of items which started the test or service.
Cumulative gain – It is the total sum of relevance or performance scores across a ranked list of items or over a sequence of evaluation points, ignoring the position or order of the items.
Cumulative histogram – It is a specialized graphical or mathematical distribution which shows the running total of data points (or fractions of data) for each bin plus all preceding smaller bins. Cumulative histogram is the fraction of pixels in an image with a digital number (DN) less than or equal to a specified accumulated. It is also referred to as the cumulative distribution function (CDF) when normalized.
Cumulative pore volume – It is the total volume of pores in a porous material whose radii or diameters fall within a specific, accumulated range.
Cumulative production – It is the total volume or quantity of a product (such as oil, gas, water, minerals, or manufactured goods) recovered or extracted from a well, reservoir, mine, or production line from the start of operations up to a specific point in time.
Cumulative result – It is the total quantity, value, or effect which builds up by adding or integrating individual measurements, outputs, or forces sequentially over time.
Cumulative sums forward test – It is a sequential statistical method used to detect small, persistent shifts in a process mean by adding up running totals of deviations from a target value in a forward direction.
Cumulative trauma disorder – It consists of the illnesses which develop gradually over time and involve disorders of the soft tissues of the body. Caused or aggravated by repeatedly or constantly applied excessive forces, awkward postures, or highly repetitive movements of the body.
Cumulative water influx – It is the total volume of water which flows from an underlying or surrounding aquifer into an oil or gas reservoir as reservoir pressure drops because of the fluid production.
Cunningham correction factor – It is a factor used to correct the fluid resistance because of the slip at the surface of a particle when its diameter is comparable to or smaller than the mean free path of gas molecules, accounting for the molecular motion of the gas. It is a dimensionless multiplier used in aerosol mechanics and fluid dynamics to modify Stokes’ law for the drag force on very small particles (typically sub-micrometer or smaller than 15 micrometers in ambient air).
Cup – It is a sheet metal part. It is the product of the first drawing operation. It is also a cylindrical part or shell closed at one end.
Cup-and-bob viscometer – It is a concentric cylinder or coaxial cylinder viscometer. It is a rotational device used to measure a fluid’s viscosity by shearing it in the narrow gap between an outer fixed cylinder (the cup) and an inner rotating cylinder (the bob).
Cup-and-cone-fracture – It is a mixed-mode fracture, frequently seen in tensile-test samples of a ductile material, where the central portion undergoes plane-strain fracture and the surrounding region undergoes plane-stress fracture. It is called a cup fracture (or cup-and-cone fracture) since one of the mating fracture surfaces looks like a miniature cup, i.e., it has a central depressed flat-face region surrounded by a shear lip, while the other fracture surface looks like a miniature truncated cone.
Cup, deep drawn – Deep-drawn cup is a hollow, symmetrical, cup-shaped metal part formed by using a punch to push a flat sheet metal blank into a die cavity, where the depth of the cup normally equals or exceeds its diameter.
Cupellation – It is the oxidation of molten lead containing gold and silver to produce lead oxide, thereby separating the precious metals from the base metal.
Cup-like part – It refers to a three-dimensional, hollow mechanical component featuring a closed or semi-closed bottom and continuous side walls. The main manufacturing methods used to produce these geometries are deep drawing (or cupping) for sheet metal, and back-ward extrusion for bulk forging.
Cup fracture – It is also known as cup-and-cone fracture.
Cupola – It is a cylindrical straight shaft furnace for melting metal, especially cast iron, by having the charge come in contact with the hot fuel, normally metallurgical coke. The melting metal is in direct contact with coke by forcing air under pressure through openings near its base. Vertical shaft furnace is lined with refractories used to produce cast iron by high temperature melting of metallic and mineral charge materials.
Cupola, basic – It is the cupola with refractory lining which has a basic reaction, normally magnesite, and is operated with slags high in lime. Lining can be neutral material like carbon, used with high lime slags.
Cupola blower – It is a machine which compresses a large volume of air at low pressure for operation of the cupola.
Cupola dust arrester – It is a device attached to the stack of a cupola which removes dust and sparks for the outgoing gases.
Cupola furnace – It is a cylindrical vertical melting furnace with pig iron, foundry returns and / or steel scrap as metallic charge for melting cast iron. Cupola furnace melting is a process which produces heat through the reaction (combustion) of fuel (for example, coke) and oxygen, so that the metallic charge melts and overheats, and finally gets the needed molten iron. In this process, the metallic charge is in direct contact with fuel and is blast-assisted from the tuyere for continuous melting.
Cupola, hot blast – Hot blast cupola is the cupola in which the air blast is heated to temperatures from 200 deg C to 540 deg C.
Cupola, water-cooled – It is the cupola in which the melting zone and tuyeres are cooled with water. Cooling of melting zone can be internal through jackets or steel tubing under the refractory lining. Cooling is also accomplished externally by water flowing down the outer shell.
Cupping – It is the first step in deep drawing. It is also fracture of severely worked rods or wire where one end has the appearance of a cup and the other that of a cone.
Cupping test – It is a mechanical test used to determine the ductility and stretching properties of sheet metal. It consists of measuring the maximum part depth which can be formed before fracture. The test is typically carried out by stretching the test piece clamped at its edges into a circular die using a punch with a hemispherical end. The different cup tests are Erichsen test, Olsen ductility test, and Swift cup test.
Cupric oxide (CuO) – It is a black, monoclinic crystal semi-conductor with a bandgap of roughly 1.4 electron-volts and high thermal stability up to 800 deg C.
Cupric chloride – It is specifically copper(II) chloride (CuCl2). It is an inorganic chemical compound and transition metal halide mainly utilized as a regenerable chemical etchant, an industrial homogeneous catalyst, and a core reactant in thermo-chemical energy cycles. While a chemist views cupric chloride through its ionic composition, engineers classify it based on its physical properties, mass transport behaviours, and redox (reduction-oxidation) efficiency in industrial manufacturing systems.
Cuprite – It is a copper oxide mineral with the chemical formula Cu2O [copper(I) oxide] which serves as a major high-grade copper ore.
Cupro-nickel – It is as a copper-nickel alloy containing between 5 % nickel and 30 % nickel, known for its excellent corrosion and bio-fouling resistance, particularly in marine applications. Higher strength variants can include alloying elements such as aluminum or tin, improving their mechanical properties.
Cuprous oxide (Cu2O) – It is a red, cubic crystal semi-conductor frequently utilized in rectifiers, photocells, and marine anti fouling coatings.
Cuprous thiocyanate (CuSCN) – It is also known as copper(I) thiocyanate. It is an air-stable coordination polymer and an inorganic, p-type, wide-bandgap semi-conductor. This material is favoured because of its unique optical and electronic traits, such as high optical transparency, substantial thermal stability, and solid hole-mobility performance.
Curable epoxy – It is a type of liquid or semi-liquid epoxy resin which undergoes a chemical curing process, typically an exothermic (heat-releasing) reaction triggered by a hardener, catalyst, or UV (ultra-violet) light, to transform into a stable, permanent, cross-linked thermo-setting polymer network.
Cure – It is the process by which paint is converted from the liquid to the solid state.
Cure cycle – It is the time / temperature / pressure cycle which is used to cure a thermosetting resin system or prepreg.
Cured concrete block – It is a precast masonry unit which has undergone a controlled hardening process to allow cement hydration or accelerated carbonation to reach its needed structural strength, hardness, and durability.
Cure depth – It is also known as depth of cure. It is the maximum thickness to which light, UV (ultra-violet) energy, or a chemical / thermal reaction can penetrate and effectively polymerize or harden a material from its surface.
Cured resin – It is a thermosetting polymer (such as epoxy, polyester, or silicone) which has undergone irreversible chemical cross-linking through heat, UV (ultra-violet) light, or catalysts to form a rigid, three-dimensional solid network.
Cure monitoring, electrical – It is the use of electrical techniques to detect changes in the electrical properties and / or mobility of the resin molecules during cure. It is a measuring of resin cure.
Cure profile – It defines the specific time, temperature, and pressure schedule a material (such as a thermoset composite, adhesive, or coating) undergoes during its chemical crosslinking or hardening process.
Cure shrinkage – It is the reduction in volume and physical size which occurs in thermosetting polymers, resins, or cementitious / concrete materials as they chemically transform, harden, or dry.
Cure stress – It is a residual internal stress produced during the curing cycle of composite structures. Normally, these stresses originate when different components of a wet lay-up have different thermal coefficients of expansion.
Cure temperature – It is the specific thermal environment required for a material, such as concrete, polymers, adhesives, or composites, to undergo a chemical reaction (like polymerization, crosslinking, or cement hydration) which locks in its final mechanical strength, hardness, and durability.
Curie (Ci) – This unit is used to measure the intensity of radioactivity in a sample of material. The Curie is equal to 37 billion disintegrations per second, which is approximately the activity of 1 gram of radium. A curie is also a quantity of any radionuclide which decays at a rate of 37 billion disintegrations per second. It is named after Marie and Pierre Curie, who discovered radium in 1898.
Curie point – It is the temperature marking the transition between ferromagnetism and para-magnetism, or between the ferroelectric phase and the paraelectric phase.
Curie temperature – It is the temperature marking the transition between ferro-magnetism and para-magnetism, or between the ferro-electric phase and the para-electric phase. It is also known as Curie point.
Curie transition temperature – It is the critical temperature at which a material undergoes a reversible phase change, losing its permanent or spontaneous magnetic (or ferro-electric) properties to become para-magnetic (or para-electric).
Curing – It is the controlled process of maintaining optimal moisture, temperature, and environmental conditions in a material after shaping or installation so that needed chemical reactions, such as cement hydration or polymer cross-linking, can proceed and develop full strength, durability, and stability.
Curing agent – It is a catalytic or reactive agent which, when added to a resin, causes polymerization. It is also called hardener.
Curing chamber – It is a specialized enclosed room, tank, or pressure vessel which maintains controlled conditions of temperature, relative humidity (frequently near 100 %), and air-flow to regulate the hardening, hydration, polymerization, or chemical reaction of engineering materials.
Curing condition – It refers to the controlled environmental settings, specifically moisture content, temperature, and duration, maintained around a freshly placed cementitious or polymer material so that it can properly harden, gain strength, and achieve durability.
Curing membrane – It is a thin, impermeable barrier, formed by a sprayed-on liquid compound or a protective sheet, which locks mixing water inside fresh concrete to prevent premature evaporation.
Curing temperature – It is the temperature to which a paint film or adhesive is subjected to cure the paint or adhesive.
Curing time – It is the period of time needed before a sand mass reaches maximum hardness.
Curl – It is an undesirable condition caused by uneven rates of absorption or evaporation of moisture, uneven rates of contraction or expansion, or internal stresses in the material. Curl is most prevalent in laminated structures where the components have differing physical properties.
Curling – It is rounding of the edge of sheet metal into a closed or partly closed loop.
Curling dies – These are specialized stamping and forming tools designed to roll the edge of sheet metal into a hollow, circular ring or bead. Unlike basic bending or hemming which folds the metal flat, curling forces the edge to feed into a highly polished, rounded die cavity. This makes the metal continuously wrap around itself to form a protective and structural tubular profile.
Curly brace – It is a punctuation mark used to group statements, define code blocks, or construct specialized data structures.
Curly brackets – These are also known as braces. These are symbols used to group declarations and statements into blocks in programming, allowing for the nesting of these blocks within each other.
Curly grain structure – It is also known as a curly grain morphology or ‘wavy’ grain structure. It refers to a heavily distorted micro-structure where individual crystalline grains are severely bent, folded, or curved. This unique morphology typically appears on the transverse (cross-sectional) view of heavily cold-worked materials.
Current – It is the net transfer of electric charge per unit time. It is also called electric current.
Current amplifier – It is a circuit which accepts a current source as its input and delivers an amplified version of that current to a load, enabling current gain through the relationship between input and output currents.
Current carrying capacity – It is also known as ampacity. It is the maximum continuous electrical current a conductor, cable, or printed circuit board trace can safely carry without exceeding its allowable operating temperature or suffering immediate or long-term damage.
Current chopping – It refers to the premature, sudden extinction of an electric arc in a circuit breaker or switchgear before the alternating current (AC) naturally reaches zero. It normally happens when interrupting low inductive currents, such as switching off unloaded transformers, small motors, or shunt reactors.
Current chopping control – It is a method which limits the current between specified upper and lower limits by directly controlling the switching device, mainly suited for low-speed operation below the base speed.
Current coil i- It is a low-impedance electrical conductor wound into one or more loops and connected in series with a load to measure or convert electric current into a proportional magnetic field.
Current compensator – It is a control mechanism or electrical device which adjusts and shapes electric current, or compensates for reactive power, voltage imbalances, and steady-state errors, to stabilize and optimize an electrical or power system.
Current-controlled voltage source inverter – It is a power electronic converter which uses a voltage-source inverter topology (fed by a stiff direct current voltage source / capacitor) but operates under an inner or closed-loop current-regulation scheme.
Current control loop – It is an inner feedback loop which continuously measures and regulates electrical current (such as in an inductor, motor winding, or power converter) to match a target reference value. It is very frequently used in power electronics (like direct current-direct current converters and pulse-width modulation rectifiers), and motor drives as part of a cascade (multi-loop) control structure.
Current conveyor – It is a three-terminal analog electronic building block which acts as a unity-gain current-mode amplifier.
Current crowding effect – It is the non-uniform distribution of electrical current density across a conductor, semi-conductor, electrical contact, or p-n junction. Instead of spreading evenly, the current concentrates or ‘crows’ into localized pathways of lower resistance, sharp corners, or contact edges.
Current decay – In spot, seam, or projection welding, it is the controlled reduction of the welding current from its peak amplitude to a lower value to prevent excessively rapid cooling of the weld nugget.
Current decomposition method – It is a mathematical or signal-processing technique used to separate a total electrical current waveform into distinct, physically meaningful components (such as active / instantaneous components, reactive components, harmonics, or distortion currents) to analyze power flow, energy transfer, and power quality.
Current density – It is the current flowing to or from a unit area of an electrode surface.
Current direction – It refers to the flow of electrical current from the positive to the negative potential end of a conductor, regardless of the actual motion of the charge carriers.
Current distribution – It describes how electric current is spatially spread out in magnitude and phase across a conductor, circuit element, antenna, or electro-chemical system.
Current divider – It is a simple parallel circuit that splits an incoming electrical current into multiple separate paths or branches.
Current drain – It is also called current draw or current demand. It is the quantity of electrical current a device, component, or circuit pulls from a power or voltage source during operation.
Current-driven device – It is also called current-controlled device. It is an electrical or electronic component whose operating state, switching action, or output current is directly regulated or initiated by an input electric current rather than an applied voltage.
Current droop – It is the decrease in photon output per ampere input when LED (light-emitting diode) packages are driven at currents higher than their nominal drive current, resulting in reduced photon efficacy. It occurs due to factors such as increased forward voltage and phenomena like Auger recombination and non-radiative recombination within the LED (light-emitting diode) structure.
Current duty ratio – It is frequently called duty cycle or duty factor. It is the ratio of the ‘on’ time (active current or pulse duration) to the total cycle time in a periodic electrical or switching signal, usually written as a decimal or a percentage.
Current efficiency – It is the ratio of the electro-chemical equivalent current density for a specific reaction to the total applied current density. It is also the proportion of current used in a given process to accomplish a desired result. In electro-plating, it is the proportion used in depositing or dissolving metal.
Current-fed inverter – It is a power electronic circuit which converts a direct current (DC) input into an alternating current (AC) output. Unlike a voltage-source inverter which maintains a constant voltage, a current-fed inverter (CFI) is fed by a stiff, constant direct current source (normally created using a direct current supply with a large series inductor).
Current feedback amplifier – It is a type of operational amplifier or feedback circuit where the error signal which controls the output is a current rather than a voltage.
Current gain – It is the ratio between the collector (output) and base (input) current in an electronic circuit or amplifier, denoted as ‘Ai = Iout / Iin’. It varies with operating conditions such as collector current, voltage, and temperature, and is specified in a range on data sheets.
Current harmonic – It is a sinusoidal component of an alternating current (AC) wave-form with a frequency which is an integer (whole-number) multiple of the fundamental power frequency (typically 50 hertz or 60 hertz). When these higher-frequency sine waves superimpose onto the fundamental wave, they deform the clean sinusoidal shape into a distorted wave-form.
Current injection – It refers to the process of supplying electrical current through specific electrodes in a system, frequently in pairs, to get measurement data. This technique can involve bipolar current sources and can utilize multiple electrodes to generate a comprehensive set of measurements.
Current instruction register – It is a special-purpose register in a computer’s central processing unit (CPU) which temporarily stores the instruction currently being decoded and executed.
Current-limiting reactor – It is a passive inductive electrical component connected in series with a power system to add inductive reactance and limit the magnitude of short-circuit fault currents.
Current-limiting resistor – It is a protective resistor placed in series with a circuit element to restrict electrical current to a safe maximum level and prevent over-current damage.
Current programme status register – It is a register in a computer processor which stores information about the current mode, banked registers, state, instruction sets, interrupt masks, and condition flags of the processor.
Current reference signal – It is also called current reference circuit. It is a stable, predefined electric current used as a standard, setpoint, or bias source in electrical, electronic, and control engineering.
Current sense resistor – it is a precision, low-resistance component placed in series within an electrical circuit to measure current indirectly by detecting a proportional voltage drop.
Current source inverter – It is a type of direct current-alternating current inverter which converts direct current input current into alternating current at a given frequency. The frequency of the output alternating current depends on the frequency of the switching devices such as thyristors, transistors, etc. It is also known as a current-fed inverter (CFI) and the input current of this inverter remains constant. In an ideal current source inverter, the output current is independent of the load. However, the output voltage is dependent on the nature of the load. Current source inverters (CSIs) are ideal for various applications such as speed control drives for alternating current motors, synchronous motor starting, plasma generators, induction heaters, uninterruptible power supply units, IM (international mounting) motors, lagging Var (voltage ampere reactive compensators, and power factor correction units
Current source rectifier – It has a step-down characteristic different from voltage source rectifier (VSR) when the converter operates in rectification mode. Because of the simple structure of the current source rectifier (CSR), it has the advantages of wide range output voltage regulation and easy parallel operation, and high reliability when direct current short circuits.
Current transformers – The primary conductor of a current transformer typically has only one turn. This is not really a turn or wrap around the core but just a conductor or bus going through the ‘window’. The primary conductor never has more than a very few turns, while the secondary coil can have a large number of turns, depending upon how much the current is to be stepped down. In majority of the cases, the primary conductor of a current transformer is a single wire or bus bar, and the secondary coil is wound on a laminated magnetic core, placed around the conductor in which the current needs to be measured.
Current velocity -It corresponds to drift velocity. It is the average net speed which free charge carriers (like electrons) acquire because of an applied electric field. It is the directional speed of charge movement superimposed over their random thermal motion.
Current-voltage characteristic – It is a graphical or mathematical relationship between the electric current flowing through an electronic device, circuit, or material and the potential difference (voltage) applied across its terminals.
Current-voltage diagram – It is normally called an I-V curve or characteristic curve. It is a graphical plot showing the relationship between the electrical current flowing through an electronic device or circuit and the voltage applied across its terminals.
Current wave-form – It is the time-domain graphical representation showing how an electrical current’s magnitude and direction change over time.
Current year – It is the twelve-month period which is presently underway, spanning the ongoing calendar, financial, or fiscal cycle.
Cursor – It is a visible and moving pointer which the user controls with a mouse, touchpad or similar input device such as a trackball. When a user moves the cursor, the computer redraws it at the new location.
Cursor control – It refers to the hardware and software mechanisms used to precisely manipulate a visual pointer or text indicator on a computer screen. It is the method of steering spatial or textual coordinates on a graphical user interface (GUI).
Curtailment – In power systems, – it means the intentional reduction of electricity generation (or electrical load) ordered by grid operators to maintain stability and balance. In structural concrete design, curtailment refers to the practice of stopping or cutting reinforcement bars (rebar) inside concrete beams or slabs where they are no longer required to resist bending moments.
Curtailment programme – It is a formal, managed initiative where a grid operator, such as a transmission system operator (TSO) or distribution system operator (DSO), intentionally reduces power generation (supply curtailment) or forces a reduction in electricity consumption (load curtailment) to maintain stability, prevent overloads, or balance supply and demand.
Curtain coating – It is a method of coating which can be used with low-viscosity resins or solutions, suspensions, or emulsions of resins in which the substrate to be coated is passed through and perpendicular to a freely falling liquid curtain (or waterfall). The flow rate of the falling liquid and the linear speed of the substrate passing through the curtain are coordinated in accordance with the thickness of coating desired.
Curtain wall – It is a non-structural outer covering of a building which is attached to the building structure to protect against weather, typically made from lightweight materials like aluminum and glass. It is designed to resist air and water infiltration, as well as sway induced by wind and seismic forces, without carrying any dead-load weight from the building itself.
Curtis stage – It is a velocity-compounded impulse turbine stage which drops steam pressure entirely in the nozzles and extracts kinetic energy across multiple rows of moving and fixed blades.
Curvature-driven migration – It is the movement of a material interface, such as a grain boundary, phase boundary, or domain wall, driven by a reduction in the total free energy of the system. This process is fundamental to understanding grain growth, recrystallization, and microstructural evolution in poly-crystalline materials.
Curvature of field -It is a property of a lens which causes the image of a plane to be focused into a curved surface instead of a plane.
Curvature sensor – It is a device which directly measures the curvature of structures, as opposed to indirectly measuring strain, and can include technologies like fibre-optic sensors or flexo-electric sensors, which are designed for applications in structural integrity monitoring.
Curve – It is a smooth, continuous bend or mathematical trajectory used either to transition smoothly between straight alignments (in civil / transportation engineering) or to represent geometric laws and functional relationships in design and drafting. They are broadly split into two main domains namely civil and transportation engineering curves (used for roads, railways, and canals) and geometric / design engineering curves (used in mechanical drafting, CAD (computer aided design), and kinematics).
Curve analysis – It is a method which matches field data against a set of type curves to get the best fit, facilitating the calculation of future production rates and reserves in the context of decline curve analysis. It involves plotting dimensionless rate against dimensionless time and combines transient flow regimes with boundary dominated flow regimes.
Curve behaviour – It can refer to several distinct concepts depending on the discipline, such as material responses, electrical characteristics, mechanical motion, or structural alignment.
Curve conveyor – It is a versatile wheel, roller, or belt conveyor designed to curve at specific sections, preserving seamless product flow and adapting to spatial needs, requiring specialized maintenance.
Curved axis – It refers to the longitudinal centre-line of a structural member, such as an arch, hook, link, or curved beam, which follows a non-linear or curvilinear path rather than a straight line.
Curved beam – It is a structural or mechanical member in which central (neutral) axis forms an arc or curve even before any external load is applied.
Curved-crease folding – It is the process of bending a flat sheet of material along a curved line to create a complex three-dimensional shape.
Curved path – It is a trajectory or alignment which changes direction continuously over space, needing a combination of tangential and normal (centripetal) acceleration.
Curve evolution – It refers to the dynamic process by which a geometric curve changes its shape, position, or length over time as per a governing mathematical rule, typically a partial differential equation (PDE) based on its curvature.
Curve modelling – It is the mathematical representation or approximation of lines, shapes, and data trends using geometric or statistical functions. It is used in computer-aided design (CAD), computer graphics, and manufacturing to define physical parts, surfaces, and trajectories (such as automotive bodies or aerospace components). In data and empirical curve modelling, it is used to find a mathematical expression which best describes a set of measured or experimental data points.
Curve segment – It is a distinct, bounded portion of a curve defined by two endpoints (regular points) and specific shape control parameters, such as tangent vectors, radii, or polynomial coefficients.
Curve skeleton – Skeleton curves are defined as the curves which connect peak loads at each load level in both positive and negative directions, showing the differences in load-carrying capacity and ductility of samples.
Curve squeal – It is a strongly tonal noise produced by the interaction between wheel and rail during curving, resulting from the vibration of the wheel at one of its resonances because of the unsteady transverse forces. It can be distinguished from flange squeal, which is characterized by a more intermittent nature and a higher frequency content.
Curvic coupling – It is a precision-ground face spline with curved convex and concave teeth arranged in a circle on the mating faces of two rotating machine components. It acts as a rigid, self-centering connection used to align and transmit high torque between coaxial shafts, turbine discs, and compressor stages (such as in gas turbine engines).
Curvilinear motion – It is the motion of an object moving in a curved path, e.g., a stone thrown into the air at an angle. Curvilinear motion describes the motion of a moving particles which conforms to a known or fixed curve. The study of such motion involves the use of two co-ordinate systems, the first being planar motion and the latter being cylindrical motion.
Curving behaviour – It refers to the performance of wheelsets in navigating curves, which is influenced by factors such as wheel conicity, yaw stiffness in suspension, and the alignment of wheelsets. Effective management of these factors can improve stability, reduce wear, and eliminate issues like squeal during curving.
Cushion blocks – These are normally plywood pads placed on top of precast concrete piles to eliminate spalling.
Cushion pad – It is a pad of resilient material or hardwood placed between the drive cap insert, or helmet, and drive cap adapter.
Cushion pressure – It is the controllable force or counter-pressure applied upward by a hydraulic or pneumatic cylinder system embedded in the bed of a press machine. In fluid power and cylinders, It is the localized back-pressure created when trapped air or oil is forced through a restricted escape path as a piston nears the end of its stroke.
Cuspidine – Its chemical formula is Ca4Si2O7F2. It is a fluorine-bearing calcium silicate crystalline mineral which plays an important role in high-temperature industrial, ceramic, and metallurgical manufacturing processes. While naturally a rare geological mineral, it is highly important as a synthetic by-product intentionally developed or controlled during engineering applications.
Cu stainless steel – It is defined as a type of stainless steel which contains copper, which improves its bio-compatibility and antibacterial properties.
Custodian – Custodian is a designated role responsible for protecting, maintaining, and managing the integrity of specific assets, systems, or technical practices, rather than owning them.
Custom environment – It is a user-defined set of software, hardware, or operational parameters tailored to run specific tasks, models, or systems outside of standard default configurations.
Customer – It means the recipient or beneficiary of the output of an organization’s work effort or the purchaser of a product or service. A customer can be either external or internal to the organization. A main objective of total quality management is to exceed customer expectations, each and every time.
Customer centric organization – Customer centric organization is that organization which reorients its entire operations around the customer, increasing customer satisfaction and its own profitability in the process. It understands not only the customer values, but also the value the customer represents for its bottom line.
Customer delight – It is the result of delivering a product or service which exceeds customer expectations.
Customer expectation – It refers to the set of performance standards, functional outcomes, operational reliability, and usability traits which a client or end-user anticipates from a system, product, or service before and during delivery. Unlike general consumer goods, engineering customer expectations sit at the intersection of subjective user goals and objective technical constraints. They are translated into formal requirements through structured methods like ‘quality function deployment’ (QFD) and categorized using models like the Kano model (which splits needs into expected, normal, and exciting features).
Customer feedback – It refers to the collection, analysis, and integration of user or client reactions, performance data, feature requests, and bug reports into the product or system development lifecycle. Unlike general marketing feedback, customer feedback directly bridges the gap between voice of the customer (VoC) and technical specifications.
Customer focus – It means the meeting of the needs and expectations of the present and the potential customers by developing a comprehensive understanding of the customer needs and then delivering perceived value to the customers. The expected outcomes of a customer focus strategy are creating values for the customers which lead to the loyal customers that in turn lead to the improved organizational performance.
Customer importance rating – It is an indication of the priority of importance the customer places on a certain want. It is determined by dividing the number of times customers mention this need by the number of subjects interviewed or surveyed.
Customer relations – It refers to the ongoing process by which engineers, project managers, and technical firms communicate, collaborate, and build trust with clients to align project goals, manage scope and expectations, and secure repeat business. Unlike standalone customer service, which typically reacts to immediate support tickets or complaints, engineering customer relations is a strategic, long-term discipline.
Customer relationship management – It involves using technology to organize, automate, and synchronize sales, marketing, customer service, and technical support. The processes of the customer relationship management are related to the principles, practices, and guidelines which the organization follows when interacting with its customers.
Customer satisfaction – It is defined as ‘the number of customers, or percentage of total customers, whose reported experience with the organization, its products, or its services (ratings) exceeds specified satisfaction goals’.
Customer satisfaction survey – It is a best method of periodically assessing the customer satisfaction. The survey is an information gathering tool.
Customer segmentation – It is also known as market segmentation. It is the practical division of potential customers in a given market into discrete groups. The division is based on customers having similar appearing needs and buying characteristics so that a common market approach can be used by an organization for the marketing of its products to them in a competitive and economical manner.
Custom factory tooling – It is the design, creation, and optimization of specialized, one-of-a-kind physical devices used to cut, shape, hold, or mass-produce specific components.
Customization – It means the process of making or changing an item, service, or system to fit a specific user’s or buyer’s needs and preferences. It is the practice of modifying, configuring, or assembling a product or system to meet specific individual requirements, operational needs, or task parameters while maintaining the core efficiencies of standardized production.
Cu surface – It refers to the exposed atomic-scale or treated boundary of a copper material, characterized by its crystallographic orientation, electronic properties, and physical interaction with the surrounding environment. Cu surface refers to the different atomic structures and electronic properties of copper electrode surfaces, specifically characterized by low-index orientations such as Cu(111), Cu(100), and Cu(110), which show different reactivities towards interactions with anions like chloride. The reactivity of these surfaces is influenced by factors such as atomic density and coordination numbers.
Cut – In foundry practice, cut is to recondition moulding sand by mixing on the floor with a shovel or blade-type machine. It is also to form the sprue cavity in a mould. It is also a defect in a casting resulting from erosion of the sand by metal flowing over the mould or cored surface. In lubricant technology, it is a product or fraction got by distillation within a specified temperature range.
Cut-and-carry die – It is frequently synonymous with a progressive die. It is a multi-station metal stamping tool which performs multiple cutting, piercing, or forming operations in sequential steps during a single stroke of a press ram, while physically carrying the metal strip forward from one station to the next.
Cut-and-fill – It is a method of stoping in which ore is removed in slices, or lifts, and then the excavation is filled with rock or other waste material (backfill), before the subsequent slice is extracted.
Cut edge – It is a mechanically sheared edge got by slitting, shearing, or blanking.
Cutinite – It is a type of microscopic organic constituent (maceral) found in coal which forms from the waxy outer cuticles of terrestrial plant leaves, stems, and roots. It belongs to the liptinite (exinite) group of macerals. It is rich in hydrogen and aliphatic hydrocarbons. It fluoresces under ultra-violet (UV) light and displays low reflectance compared to other coal macerals. It contributes considerably to oil and gas generation during thermal maturation and carbonization.
Cut material – It refers to a manufactured item or component created by slicing, shearing, or die-cutting raw or intermediate materials (such as fabrics, composites, metals, or paper) into specific shapes based on a template or pattern. It is also a manufacturing method which separates a physical object or removes excess material from a work-piece by applying a directed force, thermal energy, chemical action, or erosion. The tool or energy source used is required to break the material’s structural continuity, typically producing a finished part and waste material (such as chips, swarf, or scrap).
Cut method – It refers to a technique in optimization which involves adding new constraints, known as cutting planes, to an integer programming problem to get whole solutions while preserving the optimal integer solution. This method is frequently used in conjunction with the branch-and-bound approach to efficiently solve different integer programming problems.
Cut-off – In casting, it is removing a casting from the sprue by refractory wheel or saw, arc-air torch, or gas torch. In metal-forming, for cut-off, a pair of blades positioned in dies or equipment (or a section of the die milled to produce the same effect as inserted blades) used to separate the forging from the bar after forging operations are completed. It is used only when forgings are produced from relatively long bars instead of from individual, precut multiples or blanks.
Cut-off burr – It is a projection of material left when the work-piece falls from the stock before the separating cut has been completed.
Cut-off frequency – It is the boundary frequency which separates a system’s passband (where signals pass through with minimal attenuation) from its stopband (where signals are heavily blocked or attenuated).
Cut-off machine -It is a power tool or heavy-duty industrial machine used to make quick, straight cuts through hard materials like metal, concrete, masonry, or tile. It typically uses a high-speed circular abrasive wheel, diamond blade, or toothed metal disc to slice through stock to a. it is t specific length.
Cut-off ratio (Rc) – It is a dimensionless parameter used to analyze the Diesel cycle and compression-ignition internal combustion engines. It is the ratio of the cylinder (combustion chamber) volume at the end of the constant-pressure heat addition (combustion) process to the volume at the start of the heat addition process. ‘Rc = V3/V2’, where ‘V2’ is cylinder volume at the start of fuel injection / combustion (end of the isentropic compression stroke, at top dead centre, and V3 is the cylinder volume at the end of fuel injection / combustion (where constant-pressure heat addition stops and isentropic expansion begins). Cut-off ratio physically represents the fraction of the power stroke during which heat is added to the system at constant pressure, or the extent to which the gas expands while fuel is burning.
Cut-off wave-length -It is the critical threshold wave-length which separates different propagation regimes in a wave-guides and radio frequency or an optical fibre. In wave-guides and radio frequency, it is the longest free-space wave-length which a wave-guide mode can support. Rectangular waveguide. In optical fibre, it is the shortest wave-length at which an optical fibre operates in a single-mode regime.
Cut-off wheel – It is a thin abrasive wheel for severing or slotting any material or part.
Cut-out indicator method – It is based on an application of the boundary equation of elastic theory. The main idea of this experimental-analytical method is that the cut of a plane sample is made along the fixed contour, out of which arises an additional stress-strain state. This state appears because of stresses releasing along the contour of the cutout. This (additional) field of stresses, strains, and displacements can be measured on the basis of the known interferential optical methods (method of optically sensitive coating, methods of holographic, speckle-interferometry, and method of electronic digital speckle-interferometry etc.). The discrete values of strains can be got by the other experimental methods (e.g., with the help of a small-base gauges measurement). On the basis of the analytical relations between the contour residual stresses and the stresses (or strains, displacements) arising in the sample, and which can be measured on the cut-out contour, the residual stresses can be determined. The previously mentioned stages of the proposed approach have been put to the base of all the rupture methods of the residual stresses measured. However, a main feature of the cut-out indicator method consists in the suggestion about arbitrary distribution of the residual stresses on the contour, on which the cut is carried out.
Cuts – Cuts are defects in castings resulting from erosion of the sand by the molten metal pouring over the mould or core surface.
Cutter blade – It is a hardened mechanical component or tool edge designed to slice, shear, score, or remove material from a work-piece by concentrating applied force into localized stress.
Cutter diameter – It is the nominal measurement of the circular path or outer boundary traced by the rotating cutting edges of a tool (such as an end mill, face mill, or drill).
Cutter radius – It refers to the physical radius of a rotating cutting tool (such as an end mill or drill), or the rounded profile edge at the tip of the tool.
Cutter, gate – It is a piece of sheet metal or other tool for removing a portion of the sand in a mould to form the gate or metal entrance into the casting cavity. A scoop or other form of cutting gates in the mould.
Cutter, sprue – It is a piece of metal tubing or other tool used to remove a portion of the sand from a mould to form the sprue or passage from the exterior of the mould to the gate. It is also a machine used for shearing sprues and gates from castings.
Cutting – It is a manufacturing process which separates a physical object into parts or removes unwanted material as chips using a directed mechanical, thermal, or chemical force.
Cutting angle – It is the geometric relationship and angular orientation formed between the cutting face (or edge) of a tool and the surface or path of the work-piece being cut. Since a single angle does not fully describe a tool, ‘cutting angle’ normally refers to a system of specialized tool geometry angles which dictate how a tool shears material, manages heat, and removes chips.
Cutting attachment – It is a device for converting an oxy-fuel gas welding torch into an oxygen cutting torch.
Cutting blade – It is a tool essential for belt splicing or repair, demanding regular inspections for sharpness and consistent effectiveness.
Cutting blow pipe – It is a non-standard term for cutting torch which is a device used in air carbon arc cutting, gas tungsten arc cutting, and plasma arc cutting for controlling the position of the electrode, to transfer current, and to control the flow of gases.
Cutting cycle – It refers to the predefined, sequential series of movements and operations performed by a cutting tool to complete a specific machining task on a work-piece. It is very frequently associated with computer numerical control (CNC) machining, where complex operations are condensed into simplified, automated commands known as canned cycles or fixed cycles.
Cutting down – It is removing roughness or irregularities of a metal surface by abrasive action.
Cutting edge – It is the leading edge of a cutting tool (such as a lathe tool, drill, or milling cutter) where a line of contact is made with the work during machining.
Cutting edge radius – Itis defined as the radius of the cutting edge of a micro drill, which significantly affects the performance, cutting forces, chip formation, and quality of micro holes, with an increase in this radius leading to adverse effects such as reduced dimensional accuracy and surface integrity due to wear.
Cutting element – It is the specific component or hard surface of an instrument which comes into direct contact with a work-piece to shear, fracture, or displace material, removing the excess as chips or scrap.
Cutting emissions – It refers to the reduction of carbon di-oxide and other green-house gases released into the atmosphere, mainly through changes in energy generation practices, such as decreasing coal-fired power generation and increasing the use of renewable technologies.
Cutting feed – It is the distance a cutting tool advances along or into a work-piece during one revolution or per tooth. It is one of the foundational parameters in machining operations like turning, milling, and drilling.
Cutting fluid – It is a fluid used in metal cutting to improve finish, tool life, or dimensional accuracy. On being flowed over the tool and work, the fluid reduces friction, the heat generated, and tool wear, and prevents galling. It conducts the heat away from the point of generation and also serves to wash the chips away.
Cutting force – It is the physical resistance offered by a work-piece material when a cutting tool penetrates and deforms it to form a chip during manufacturing processes like turning, milling, and drilling.
Cutting force components – These refer to the individual forces acting during machining processes, which can be decomposed into tangential, radial, and axial components. These components measure the resistance of the material being machined and are influenced by factors such as material type and cutting parameters.
Cutting inserts – These are also known as indexable inserts. These are replaceable, detachable cutting tips made of highly durable materials which clamp onto a tool holder body to cut, shape, and finish work-pieces. Instead of discarding an entire tool when the edge dulls, machinists simply loosen a screw or clamp, rotate (index) the insert to a fresh cutting edge, or swap it out entirely.
Cutting materials – These normally refers to the specialized substances used to make cutting tools which shape, shear, or remove excess metal and other work-pieces through machining.
Cutting method – It is a process which separates a physical object or removes unwanted material from a work-piece using an acutely directed force, wedge shape, thermal energy, or chemical / electrical action.
Cutting nozzle – It is a non-standard term for cutting tip which is the part of an oxygen cutting torch from which the gases issue.
Cutting oil – It is a specialized type of cutting fluid used in metalworking operations, such as turning, drilling, milling, and grinding, to lubricate and cool the interface between the cutting tool and the workpiece.
Cutting operation – It is a manufacturing process which separates, divides, or removes material from a work-piece by applying a directed force which stresses the material beyond its ultimate shear strength.
Cutting parameters – These are the core set of control variables which govern a metal-cutting or material-removal process (such as turning, milling, or drilling). These parameters directly dictate tool life, surface finish, dimensional accuracy, and production rate. The three main cutting parameters are cutting speed, feed rate, and depth of cut.
Cutting performance – It refers to the efficiency, quality, and economic effectiveness of a material-removal process (such as turning, milling, drilling, or rock excavation). It measures how well a tool removes material from a workpiece while balancing productivity and tool longevity.
Cutting period – It refers to the active portion of a machining cycle in which the cutting edge of a tool is physically engaged in removing material from the work-piece.
Cutting plane – It an imaginary flat surface which slices through a 3-dimensional component or assembly to expose its internal structure.
Cutting plane line – It is a thick, special-purpose line which shows where an imaginary cut has been made through an object to reveal its internal features and hidden details.
Cutting power (Pc) – It is the rate of work done or energy consumed during a machining operation (such as turning, milling, or drilling) to deform and separate material from a work-piece. It is the product of the tangential cutting force (Fc) and the cutting speed (Vc). ‘Pc = Fc x Vc’.
Cutting speed – It is the linear or peripheral speed of relative motion between the tool and work-piece in the principal direction of cutting.
Cutting structure – It refers to the specific arrangement, geometry, and design of the parts of a tool or machine that physically engage, fracture, or remove material from a substrate. In drilling and tunneling, the cutting structure is the mechanical configuration of teeth, cutters, or inserts on a drill bit or tunnel boring machine (TBM) cutterhead. In machining, the cutting structure refers to the geometric components and systemic layout of the tool-workpiece interface.
Cutting temperature – It is the thermal condition or heat generated in the cutting zone when a tool removes material from a work-piece (such as in turning, milling, or drilling). [It represents the temperature rise at the cutting-edge surface, tool-chip interface, and surrounding deformation zones, typically ranging from 200 deg C to 1,200 deg C depending on the material and parameters.
Cutting tip – It is that part of an oxygen cutting torch from which the gases issue.
Cut-to-length – It consists of the process to uncoil sections of flat-rolled steel and cut them into a desired length. Product that is cut to length is normally shipped flat-stacked.
Cut-to-length (CTL) line – It is an automated industrial system used in manufacturing to uncoil, flatten, measure, and shear large metal coils into flat sheets of precise lengths.
Cutting tool – It is a hardened, sharp-edged device mounted on a machine tool to cut, shape, and remove excess material from a work-piece through shear deformation. Cutting tools are implements which are used to remove or shape material through shear deformation during manufacturing processes. They are characterized by sharp edges or points which are used to remove material in the form of chips. Examples are drills, saws, knives, and milling cutters.
Cutting tool condition – It refers to the physical and structural state of a cutting tool during a machining operation. It measures the extent of tool degradation, such as flank wear, crater wear, chipping, micro-cracks, or catastrophic breakage, and how these changes affect the workpiece.
Cutting tool design – It is the process of creating and shaping specialized wedge-shaped instruments to remove material from a workpiece through shearing. –
Cutting torch – In arc cutting, it is a device used in air carbon arc cutting, gas tungsten arc cutting, and plasma arc cutting to control the position of the electrode, to transfer current, and to control the flow of gases. In oxy-fuel cutting, it is a device used for directing the preheating flame produced by the controlled combustion of fuel gases and to direct and control the cutting oxygen.
Cuttings transport – It refers to the movement of cuttings grains in a borehole, influenced by factors such as inclination, annulus velocity, foam flow rate, and eccentricity, which affect the thickness of the cuttings bed and the efficiency of removal from the well.
Cutting velocity – It is the speed difference (relative velocity) between the cutting edge of a tool and the surface of the work-piece being machined. It is measured in meters per minute. It is a vector quantity (having both magnitude and direction) representing the tangential speed at the point of contact.
Cutting zone – It refers to the localized region where a cutting tool interacts with a work-piece to remove material, separate chips, and shape a component. The cutting zone is normally broken down into three primary deformation and contact regions during metal cutting. The first is the primary deformation or shear zone. It is the narrow region ahead of the cutting tool’s edge where the bulk work-piece material undergoes intense plastic deformation and shearing along a designated shear plane. The second is the secondary deformation zone (tool-chip interface). It is the contact area where the newly formed chip slides under high pressure over the rake face of the cutting tool. The third is the tertiary deformation zone (tool-work-piece interface). It is the contact region between the flank (clearance) face of the cutting tool and the newly machined surface of the work-piece.
Cut wire blasting – It consists of blasting with short, cut lengths of metal wire.
C-weighting – It refers to a frequency weighting that follows the 100 phon curve, providing a flatter response compared to A-weighting, and is used for measuring peak noise levels, particularly for impulsive sounds.
Cyamelide – It is an amorphous white solid with the approximate formula (HNC)x. It is the product of the polymerization of cyanic acid together with its cyclic trimer cyanuric acid. It is a porcelain-like white substance which is insoluble in water.
Cyanate ester (CE) – It is a thermosetting resin known for its low water absorption, excellent mechanical properties, low shrinkage during curing, and superior dielectric and chemical resistance, making it widely utilized in several applications.
Cyanate ester resins – These are thermosetting resins which are derived from bisphenols or polyphenols, and are available as monomers, oligomers, blends, and solutions.
Cyanic acid – It is a colourless, poisonous, and volatile liquid chemical compound with the chemical formula HOCN. It turns into a solid at very low temperatures. It is highly unstable and reactive. It breaks down quickly in water into ammonia and carbon di-oxide.
Cyanic copper – It is the copper which is electro-deposited from an alkali-cyanide solution containing a complex ion made up of univalent copper and the cyanide radical.
Cyanidation – It is a hydrometallurgical technique used to extract gold and silver from low-grade ores by dissolving the precious metals in a dilute alkaline cyanide solution.
Cyanide – It is a chemical compound which contains a C≡N functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. In inorganic cyanides, the cyanide group is present as the cyanide anion -C≡N. This anion is extremely poisonous. Soluble salts such as sodium cyanide (NaCN) and potassium cyanide (KCN) are highly toxic. Hydrogen cyanide is produced by the combustion or pyrolysis of certain materials under oxygen-deficient conditions.
Cyanide bath – It refers to a liquid solution or molten salt mixture containing cyanide compounds (such as sodium cyanide or potassium cyanide) used mainly in two contexts. The first is electro-plating (metal deposition), where it is an alkaline tank solution (typically operating at a pH of 12 or higher) where metal-cyanide complexes (like sodium zincate or silver cyanide / gold cyanide complexes) dissolve and deposit a a smooth, uniform metallic layer onto a substrate. The second is case hardening (cyaniding or liquid carburizing), which is a thermo-chemical surface-hardening process where low-carbon or medium-carbon steel components are immersed in a molten salt bath containing cyanide (along with carbonates and chlorides).
Cyanide process – It is a hydrometallurgical technique used to extract gold and silver from low-grade ores by dissolving the precious metals into a dilute alkaline cyanide solution.
Cyanide slimes – These are finely divided metallic precipitates which are formed when precious metals are extracted from their ores using cyanide solutions.
Cyanide solution – It refers to a liquid medium which contains cyanide ions, which can react with metals to form metal cyanide complexes, as observed in processes such as the dissolution of precious metals and the precipitation of zinc during cyanidation operations.
Cyaniding – It is a case-hardening process in which a ferrous material is heated above the lower transformation temperature range in a molten salt containing cyanide to cause simultaneous absorption of carbon and nitrogen at the surface and, by diffusion, create a concentration gradient. Quench hardening completes the process.
Cyanoacrylate adhesive – It is normally known as ‘super glue’ or CA glue. It is a single-component, solvent-free, fast-acting reactive liquid adhesive which polymerizes almost instantaneously upon contact with trace surface moisture and weak bases.
Cyanoacrylate glue – It is normally known as CA glue or super glue. It is a single-component, solvent-free, reactive liquid monomer which polymerizes almost instantaneously at room temperature. It is an alpha-cyanoacrylate ester with the general chemical formula CH2=C(CN)CO2R, where the side group (R) can be methyl, ethyl, butyl, or alkoxy. It cures to form clear, hard glassy resins, mainly used for bonding several substrates. It can polymerize through radical and anionic mechanisms.
Cyanuric acid – It is a chemical compound with a formula C3H3N3O3 (a symmetrical triazine ring). It is used as a chlorine stabilizer and sunscreen for free chlorine in outdoor water treatment systems. It acts as a reversible, weak-bonding agent that shields hypochlorous acid from ultra-violet (UV) photolysis. Without cyanuric acid (CYA), direct sunlight degrades up to 90 % of free chlorine within two hours. It is produced through the thermal decomposition of urea.
Cyber-attack – It-is a deliberate, malicious action targeting computer systems, networks, or digital-physical infrastructure (such as micro-grids, industrial control systems, or automated machinery) to compromise functionality, disrupt services, or exfiltrate data. Unlike purely IT (information technology)-focused definitions, cyber-attacks frequently bridge the digital and physical worlds, meaning a logical or network intrusion can cause real-world mechanical, electrical, or structural damage.
Cyber-physical systems -These systems are defined as the integration of computation with physical processes, where embedded computers and networks monitor and control these processes through feedback loops which enable mutual interaction. Cyber-physical systems (CPS) are foundational to the development of smart systems, including advanced robotics and real-time integrated systems which play critical roles in several infrastructures.
Cyber-security – It is the practice of designing, building, and integrating security controls directly into hardware, software, and physical-digital system, such as IT (information technology), OT (operational technology), and industrial machinery, from the very beginning to prevent vulnerabilities. Unlike traditional cyber-security, which frequently focuses reactively on monitoring, patching, and incident response, cybersecurity treats security as a core structural requirement.
Cyberware – It refers to the hardware, software, and communication components embedded within cyber-physical systems (CPS) which enable them to interact with the physical world. It defines the technological infrastructure which bridges abstract computational logic with tangible physical operations.
Cycle – It is a complete repeating sequence of the operation in a specific process in moulding. Cycle time is measured by the elapsed time between one point in the cycle to the same point in the next cycle. In fatigue, one complete sequence of values of applied load which is repeated periodically.
Cycle activity – It means life-cycle activity. It refers to a specific, structured task or phase within a larger, repeating or sequential system process, such as a project management loop, a product development stage, or a discrete-event simulation model.
Cycle analysis – It typically refers to either life cycle assessment (LCA) which is evaluating the environmental and resource impacts of a product, process, or system from start to finish, or thermodynamic / operational cycle analysis, which models energy and mass flows in repeating mechanical or thermal processes (such as a power plant or engine cycle). Here, It can also mean evaluating the repeating states of a working fluid or system.
Cycle annealing – It is an annealing process employing a pre-determined and closely controlled time-temperature cycle to produce specific properties or micro-structures.
Cycle application – It refers to the practical uses of thermodynamic cycles. It is the practical implementation and utilization of a closed-loop sequence of repeating thermodynamic states and heat / work interactions (such as the Rankine cycle for steam plants, Brayton cycle for gas turbines, or supercritical CO2 (carbon di-oxide) S-CO2 (sulphur – carbon di-oxide) cycles, particularly in industries like nuclear and solar, where their efficiency and performance are evaluated through theoretical and experimental analyses.
Cycle assessment – It means life-cycle assessment (LCA). It is a standardized method used to measure the environmental impacts and resource use of a product, process, or service across its entire existence.
Cycle calculation – It determines the total active time needed to complete a single unit, process step, or operational repetition from start to finish.
Cycle component – It refers to a specific, functional device, module, or part which makes up a closed-loop repeating system, such as a thermodynamic cycle, a refrigeration circuit, an engine, or a fluid power loop.
Cycle count – It refers to the measurement of the number of cycles taken by a specific routine during execution, frequently used to benchmark performance before and after optimization.
Cycle counting – It is an inventory auditing method which counts a small part of the inventory on a regular schedule, instead of counting everything at once. Since each count is small, it happens alongside normal work, and the records stay accurate without shutting down for a full physical inventory.
Cycle design – It is a comprehensive approach to sustainability which optimizes the entire life-span of products, focusing on resource efficiency, waste minimization, and the principles of the circular economy. It facilitates closed-loop systems which ensure materials are continually reused rather than becoming waste.
Cycle efficiency – It is the ratio of useful output energy (or work) produced by a thermodynamic or operational cycle to the total energy input (or fuel / charge energy) supplied to it.
Cycle fatigue – It is metal / material fatigue. It is the progressive, permanent structural damage and eventual cracking or fracture of a material subjected to repeated or fluctuating mechanical, thermal, or dynamic loads over time. Even though the peak applied stress in each cycle is well below the material’s static yield strength or ultimate tensile strength, the cumulative effect of thousands or millions of cycles causes microscopic flaws to grow into macroscopic cracks.
Cycle frequency – It is the number of complete cycles or repetitions of a periodic wave-form, oscillation, or AC (alternative current) signal which occur in one second. It is measured in hertz, where 1 hertz is 1 cycle per second.
Cycle impact – It is very frequently referred to in engineering as a life cycle impact. It is the overall environmental, economic, or social effect caused by a product, material, or system across its entire life-span. Rather than looking at just the manufacturing or operational phase, engineering analysis evaluates the impact from start to finish.
Cycle life – It is the total number of repetitive charge-discharge or stress-load cycles, a system, component, or material can endure before its performance or capacity degrades below a defined failure threshold.
Cycle management – It is very frequently referred to as lifecycle management or project / engineering cycle management. It is the structured process of overseeing a system, product, or project through every phase of its existence, from initial concept and design all the way to operation, maintenance, and final decommissioning. Instead of treating development, testing, and operations as isolated events, it connects them into a continuous, accountable framework.
Cycle period – It is the time needed to complete one full, repeating pattern or oscillation of a wave-form, signal, or alternating current (AC). It is also the total elapsed time needed to complete one full production unit, task, or repeating operational sequence from start to finish. Cycle period is also the total duration of an active (on-time) and inactive (off-time) operating sequence for a machine or motor subjected to repetitive load changes.
Cycle plant – It very frequently referred to as a combined-cycle power plant (CCPP) or combined-cycle gas turbine (CCGT) plant. It is an energy generation facility which integrates two or more thermodynamic cycles to convert fuel into mechanical and electrical energy at high efficiency.
Cycle power plant – It is very frequently a combined cycle power plant or CCPP. It is an engineering system which integrates two or more thermodynamic power cycles to convert heat energy into electricity with high efficiency.
Cycles per instruction – It is a fundamental performance metric in computer architecture and engineering which measures the average number of clock cycles a processor needs to execute each instruction.
Cycle test – It is a procedure whereby a product is put through an interval of time during which a phenomenon is completed. This can be a set number of events or it can be a continuous operation until
something in the product fails.
Cycle time – It is the time to produce a part. Cycle time is the reciprocal of production rate. It is also the duration for a complete cycle of conveyor operation, necessitating continuous monitoring for efficiency and identification of potential bottlenecks.
Cyclical loading – It is the repetitive loading and unloading of materials on the conveyor, demanding regular inspections for wear, alignment, and sustained structural integrity.
Cyclic amine – It is an organic nitrogen-containing compound in which the nitrogen atom forms part of a ring structure (either saturated, unsaturated, or aromatic).
Cyclic bending test – It is a destructive mechanical testing method used to evaluate a material’s fatigue resistance, ductility, and deformation behaviour when subjected to repeated, alternating bending forces. Unlike standard monotonic bend tests which apply a single continuous force until failure, cyclic bending subjects the samples to repeated loading and unloading cycles. This simulates the real-world operational stresses which cause components like rotating shafts, wires, and structural beams to degrade over time.
Cyclic buffer – It is a fixed-size data structure utilized in software and hardware engineering to manage continuous streams of data. Architecturally, it behaves as if its end is connected directly to its beginning, allowing the memory footprint to remain entirely constant while processing potentially infinite data sequences.
Cyclic carbonates – These are cyclic compounds which serve as monomers for the synthesis of poly-carbonates and copolymers, with research focusing on both aromatic and aliphatic types for several applications in materials science.
Cyclic code – It is a type of linear block code used in engineering and telecommunications where any circular shift (left or right) of a valid codeword produces another valid codeword.
Cyclic convolution – It is also known as circular convolution. It is a mathematical operation which combines two finite discrete-time sequences of the same length ‘N’ by shifting one sequence cyclically and multiplying its entries with the other.
Cyclic corrosion test – In the cyclic corrosion test, temperature and relative humidity are varied to simulate typical wet / dry cycles like the ones taking place in natural outdoor environments. Additionally, the samples are sprinkled with a dilute NaCl solution (1 %) twice a week to induce corrosion. Though this test is still not directly representative of most real atmospheres, due to the wet / dry cycles as well as the lower chloride concentration, it is much better suited for triggering natural corrosion processes than the simple salt spray test. However, the test requires longer test times (several weeks).
Cyclic corrosion test with exposure to ultra-violet (UV) radiation – This test in addition exposes the samples to high-energy ultra-violet radiation. It is combined with water condensation, with chloride exposure and a freezing period. Organic polymers such as paints and varnishes can show degradation when exposed to sun light. This test is therefore mainly used for products with organic coatings. Apart from corrosion testing, it is also used to check the ageing effect on ultra-violet sensitive products.
Cyclic creep – It is normally referred to as ratcheting or ratchetting. It is the progressive, incremental accumulation of permanent plastic deformation in a material subjected to asymmetric cyclic mechanical or thermal stresses. Unlike classic static creep, which occurs under a constant, sustained load at high temperatures, cyclic creep is driven by fluctuating stress amplitudes which superimpose onto a non-zero mean tensile stress. This phenomenon is critical in engineering because it can cause progressive dimensional changes and catastrophic structural failure even at temperatures far below the material’s standard thermal creep threshold.
Cyclic deformation – It is the repetitive, time-dependent change in shape or size of a material or structure caused by fluctuating or alternating loads.
Cyclic deformation and fatigue behaviour – These refer to how materials change shape, accumulate damage, and eventually break when subjected to repeated, fluctuating loads well below their static ultimate strength.
Cyclic delay – It is very frequently implemented as cyclic delay diversity or CDD. It is a wireless communication and signal processing technique where a transmitted signal is shifted in time in a circular (cyclic) manner across multiple antennas.
Cyclic extension – It refers to the addition of a cyclic prefix to an OFDM (orthogonal frequency-division multiplexing) symbol by copying the end of the symbol and placing it at the beginning, which helps to mitigate inter-symbol interference in dispersive channels and simplifies the design of frequency-domain equalizers.
Cyclic extrusion-compression – It is a severe plastic deformation (SPD) manufacturing process which repeatedly forces a metal sample back and forth through a smaller die to refine its grain structure and improve mechanical strength without changing its final shape.
Cyclic fatigue – It is the progressive, localized structural damage and eventual failure of a material subjected to repeated or fluctuating stress cycles at levels well below its static yield or ultimate tensile strength.
Cyclic, fatigue – Fatigue cycles refer to the repeated application of mechanical loads that contribute to the degradation of material properties over time, specifically under conditions of cyclic mechanical fatigue.
Cyclic fatigue loading – It refers to the repeated application of stress or strain on materials, leading to different fatigue damage mechanisms such as matrix cracking and fibre fracture, particularly observed in fibre-reinforced ceramic matrix composites (CMCs).
Cyclic fatigue tests – These tests refer to experiments designed to assess the fatigue strength of materials by subjecting them to repeated tension and compression cycles until fracture occurs. These tests simulate the effects of mechanical preparation on instruments in controlled conditions, determining their resistance to cyclic fatigue based on the time or number of cycles to breakage.
Cyclic hardening – It is an increase in a material’s strength and hardness caused by repeated loading and unloading (cyclic deformation).
Cyclic hardening material – It is a metal or alloy whose resistance to plastic deformation increases as it undergoes repeated, alternating loading and unloading (such as tension-compression cycles).
Cyclic hydro-carbon – It is an organic compound made only of carbon and hydrogen atoms connected in a closed ring structure. Cyclic hydro-carbon are either alicyclic hydro-carbons or aromatic hydro-carbons. Alicyclic hydro-carbons act like open-chain compounds but form a ring. They include cyclo-alkanes, cyclo-alkenes and Cyclo-alkynes. Aromatic hydro-carbons rings contain special electronic arrangements with a benzene ring as their base (e.g., benzene, toluene).
Cyclic J-integral – It is an extension of the traditional monotonic J-integral used in ‘elastic-plastic fracture mechanics’ (EPFM) to characterize fatigue crack growth (FCG) rates in ductile materials under cyclic loading.
Cyclic load – It is repetitive loading, as with regularly recurring stresses on a part, which sometimes leads to fatigue fracture. It is also the loads which change value by following a regular repeating sequence of change. Unlike a static load (which stays constant), a cyclic load varies in magnitude, direction, or frequency. Crucially, a material can experience failure under cyclic loading even when the individual peak stresses remain well below the material’s static yield strength or ultimate tensile strength.
Cyclic loading – It is the repeating process of loading and unloading a component, where stress changes in magnitude, direction, or both over time (such as shifting between tension and compression).
Cyclic loading condition – It is the repeated, fluctuating, or alternating application of a force, stress, or strain on a material or structure over time. Unlike a static load (which stays constant), a cyclic load varies in magnitude, direction, or frequency. Crucially, a material can experience failure under cyclic loading even when the individual peak stresses remain well below the material’s static yield strength or ultimate tensile strength.
Cyclic olefin copolymer – It is an amorphous, transparent thermo-plastic produced by the chain copolymerization of cyclic monomers (such as norbornene or tetra-cyclo-dodecene) with linear alpha-olefins (such as ethylene).
Cyclic plastic deformation – It is the permanent, irreversible change in a material’s shape or size which occurs when repeated, alternating loads push the stress beyond the material’s elastic limit.
Cyclic plasticity – It refers to the behaviour of a material as it undergoes repeated, permanent (plastic) deformation due to alternating or cyclic mechanical loading. Unlike monotonic plasticity, which involves a one-time continuous force (like a standard tensile test), cyclic plasticity focuses on how a metal’s internal microstructure and macro-scale stress-strain response evolve over hundreds or thousands of load reversals. It is the fundamental mechanism driving low-cycle fatigue and structural damage.
Cyclic prefix – It is an identical copy of the last portion of an OFDM (orthogonal frequency-division multiplexing) symbol which is appended before the symbol to prevent inter-symbol interference (ISI) in dispersive channels, hence preserving the orthogonality of the sub-carriers.
Cyclic redundancy check – It is a fixed-length, error-detecting code attached to data blocks in digital transmission and storage systems. It acts as a mathematical check-sum to catch accidental corruption caused by noise, interference, or hardware faults.
Cyclic service – It refers to operating conditions where a component, structure, or system repeatedly undergoes loading and unloading cycles (or alternating on / off states) over time.
Cyclic shift – It is also called a circular shift or bitwise rotation. It is an operation which rearranges the elements or bits of a sequence, data word, or signal by rotating them in a given direction (left or right). Unlike logical or arithmetic shifts, which discard outer bits and replace them with zeros or sign bits, a cyclic shift wraps the displaced bits from one end back around to the opposite end. As a result, no data or information is lost.
Cyclic softening – It is a mechanical phenomenon where a material’s resistance to plastic deformation decreases when subjected to repeated, cyclic loading (fatigue testing).
Cyclic softening material – It loses strength and resistance to deformation over time when it experiences repeated loading and unloading.
Cyclic spectrum – It is also called the spectral correlation density or spectral correlation function. It is the Fourier transform of a signal’s cyclic auto-correlation function. It characterizes cyclo-stationary processes, signals which show statistical properties (like mean and auto-correlation) varying periodically with time. It measures the density of correlation between two spectral components of a signal separated by a specific frequency known as the cycle frequency.
Cyclic steam injection – It is also known as cyclic steam stimulation (CSS), steam soak, or the huff-and-puff method. It is a thermal enhanced oil recovery (EOR) technique used to extract heavy oil and bitumen from underground reservoirs. It is a process involving alternate injections of steam and oil production from the same well, consisting of three stages namely steam introduction, a soak period for heat transfer to lower oil viscosity, and oil extraction, repeated until production diminishes. Unlike continuous steam flooding or steam-assisted gravity drainage (SAGD) (which use separate injection and production wells), cyclic steam injection (CSI) alternates between injecting steam and producing oil through the single well-bore.
Cyclic steam stimulation – It is a heavy oil recovery method which involves the injection of steam into a single well, followed by a soaking period to heat the oil, after which the heated oil and water are extracted. This process is repeated and is mainly effective in layered reservoirs, yielding an oil recovery factor of 10 % to 20 %.
Cyclic strain in engineering refers to the repeated, time-varying deformation (change in shape or length relative to the original size) imposed on a material or structural component under repetitive or fluctuating loads.
Cyclic stress – It is the distribution of forces (also known as stresses) which change over time in a repetitive fashion, e.g., one of the large wheels used to drive an aerial lift such as a rope way. The wire cable wrapped around the wheel exerts a downward force on the wheel and the drive shaft supporting the wheel. Although the shaft, wheel, and cable move, the force remains nearly vertical relative to the ground. Hence, a point on the surface of the drive shaft undergoes tension when it is pointing towards the ground and compression when it is pointing to the sky.
Cyclic stress-strain behaviour – It describes how a material reacts when it experiences repeating loads that push and pull it back and forth over time. When a material undergoes this repeating push-and-pull, its internal structure changes. Instead of following a simple straight line or standard curve (like a one-time pull test), the relationship between stress (the internal force) and strain (the physical stretching or bending) forms closed loops called hysteresis loops.
Cyclic stress-strain curve – It is a graphical line which connects the tips of stable stress-strain hysteresis loops obtained from a material under repeated or alternating loading.
Cyclic surface yield strength – It refers to the stress threshold where a material begins to undergo permanent plastic deformation under repeated (cyclic) loading conditions, evaluated specifically with respect to the material’s surface characteristics or a cyclic stress-strain curve.
Cyclic tri-axial test – It is a laboratory procedure used to evaluate the dynamic and mechanical behaviour of soil mixtures under repeated stress and loading-unloading cycles.
Cyclic variability – It is frequently called cycle-to-cycle variability (CCV). It refers to the fluctuations in performance, pressure, or flow parameters from one operating cycle to the next, even when the system’s control settings and nominal input conditions remain constant. While it can appear in several mechanical and thermodynamic systems, it is very frequently studied in internal combustion engines (such as spark-ignition, compression-ignition, or low-temperature combustion modes.
Cyclic yield strength – It is the stress limit a material withstands under repeated or alternating loading before it begins to experience permanent plastic deformation. Unlike standard monotonic yield strength, which is measured during a single, continuous pull or push, cyclic yield strength is derived from a cyclic stress-strain curve. This curve maps how a material behaves when loads are reversed back and forth over many cycles.
Cyclo-aliphatic amines – These are amines with a ring structure which provide higher temperature resistance and toughness in cured resins compared to ethylene diamine-based aliphatic amines. They are produced through different methods, including the hydrogenation of aromatic diamines, and are normally used in applications such as epoxy adhesives and poly-ureas.
Cyclo-alkanes – These are saturated hydro-carbons which have their carbon atoms joined in a closed ring or loop structure. They have the general molecular formula ‘CnH2n’, where ’n’ is the number of carbon atoms (‘n’ is equal to 3 or higher)). They contain only carbon-to-carbon single bonds (C-C) and carbon-to-hydrogen bonds (C-H). There are no double or triple bonds. Unlike regular open-chain alkanes which form straight or branched lines, cycloalkanes loop back on themselves to form a ring.
Cyclo-alkenes – These are unsaturated hydro-carbon ring structures which contain at least one carbon-carbon double bond. These are cyclic organic compounds made of carbon and hydrogen featuring a closed ring and one or more double bonds, without being aromatic. Mono-cyclic alkenes with one double bond follow the general formula CnH(2n-2).
Cyclo-alkyne – It is a cyclic hydro-carbon which contains a closed ring of carbon atoms with at least one carbon-carbon triple bond. Its general formula is CnH2n-4) for a mono-cyclic ring with one triple bond. The carbon atoms involved in a triple bond prefer a linear, 180-degree bond angle. Bending this linear geometry into a ring creates high ring strain. Because of this strain, small rings are extremely reactive. Cyclo-octyne (CnH12) is the smallest cyclo-alkyne with enough flexibility to be isolated and stored as a stable compound at room temperature. Smaller rings (like cyclo-pentyne) exist only as transient, highly reactive intermediates.
Cyclo-butane – It is a four-carbon ring shaped like a square. It is a colourless, flammable gas with the chemical formula C4H8, featuring a ring-shaped structure made of four carbon atoms. It belongs to a group of chemicals called cyclo-alkanes, which are hydro-carbons (compounds made only of hydrogen and carbon) with closed rings.
Cycloconverter – It is (also known as a cyclo-inverter. It is a power electronic device which directly converts an alternating current (AC) power wave-form of a specific frequency and voltage into another alternating current power wave-form of a different frequency and voltage in a single stage, without using an intermediate DC (direct current) link.
Cyclodextrin – It is the cyclic degradation products of starch which contain six, seven, or eight glucose residues and have the shape of large ring molecules.
Cyclo-hexane – It is a cycloalkane with the molecular formula C6H12. Cyclohexane is non-polar. It is a colourless, flammable liquid with a distinctive detergent-like odour, reminiscent of cleaning products.
Cyclohexene – It is a colourless, flammable cycloaliphatic hydrocarbon liquid with the molecular formula C6H10, featuring a six-membered carbon ring containing one carbon–carbon double bond.
Cyclomatic complexity – It is a software metric which measures the structural complexity of a programme by counting the number of linearly independent paths through its source code. It is widely used to evaluate how hard a piece of code is to test, maintain, or trouble-shoot, as well as how prone it is to errors.
Cyclone – It is a stationary mechanical device designed to separate particulate solids or liquid droplets from a gas or liquid stream using centrifugal force and inertia. Unlike traditional filtration systems, a cyclone achieves this separation without the use of filters or moving parts, making it a highly robust, low-maintenance, and cost-effective unit operation in chemical, mechanical, and environmental engineering. Cyclones are also known as centrifugal collectors. They use cyclonic separation method for the removal of the particulate matter from the exhaust gases. They remove particulate matters by causing the dirty exhaust gas stream to flow in a spiral path inside a cylindrical chamber. In meteorology, a cyclone is a large air mass which rotates around a strong centre of low atmospheric pressure, counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere as viewed from above (opposite to an anticyclone). Cyclones are characterized by inward-spiraling winds which rotate around a zone of low pressure.
Cyclone boilers – These are a type of combustion technology designed for biomass co-firing, characterized by large, water-cooled burners which operate at high temperatures (1,650 deg C to 2,000 deg C) and utilize a slag layer to capture and combust particulate matter while allowing volatile and fine particles to burn in suspension. These boilers need minimal fuel preparation, needing only crushed fuels and are suitable for co-firing with coal.
Cyclone collector – It is a mechanical separation device which uses centrifugal force to remove particulate solids or liquid droplets from a gas or air stream without using physical filters.
Cyclone diameter – It is the inside diameter of the main cylindrical feed chamber (or barrel) of a cyclone separator. It refers to the measurement of the diameter of a cyclone dust collector, which considerably influences its efficiency and application in separating particles from an air stream. Cyclones can be categorized based on their diameter, with sizes ranging from 150 millimeters to 5,500 millimeters, and smaller diameters normally providing more force for separating smaller particles.
Cyclone dust collector – It is an air pollution control device which uses centrifugal force to separate and remove heavy particulate matter from industrial gas or air streams without using physical filters.
Cyclone filter – It is also called cyclone separator. It is a mechanical separation device which removes particulate solids or droplets from gas or liquid streams using centrifugal force and density differences, without using traditional barrier filter media.
Cyclone firing – It is an industrial combustion method where crushed or granular solid fuel (such as low-grade coal, biomass, or petroleum coke) is burned inside a horizontal, water-cooled cylindrical chamber (a cyclone furnace) at extremely high temperatures.
Cyclone inlet – It is the entry point where a gas, air, or fluid mixture carrying solid or liquid particles enters a cyclone separator. It can be either circular or rectangular, and varies in size. It plays an important role in controlling particle cut size and improving classification performance in hydro-cyclones.
Cyclone separators – Cyclone separators are gas cleaning devices which utilize the centrifugal force created by a spinning gas stream to separate particles from a gas. The gas flow is forced to follow the curved geometry of the cyclone while the inertia of particles in the flow causes them to move toward the outer wall, where they collide and are collected. In a cyclone, the particles in the spinning gas stream move progressively closer to the outer wall as they flow through the device. The gas stream can execute several complete turns as it flows from one end of the device to the other. For the design of a cyclone separator, the given gas flow rate and inner and outer radii, the length of the body of the cyclone is to ensure that a desired collection efficiency for particles of a given size be achieved. Since the length of the body of a cyclone is related through the gas flow rate to the number of turns executed by the gas stream, the design frequently consists of computing the number of turns needed to achieve specified collection efficiency.
Cyclone size – It is defined by the diameter of the cylindrical section of the cyclone, which considerably influences the cut-point and performance in separation applications. Larger cyclones are typically used for coarse separations, while smaller cyclones are preferred for fine separations because of the capacity constraints.
Cyclonic scrubber – It is an industrial pollution control device. It uses centrifugal force and liquid sprays to spin, trap, and remove dust, solid particles, or liquid droplets from industrial exhaust gas streams before the air is released.
Cyclonic separation – It is a method used to remove solid particles from gas by utilizing centrifugal force, characterized by its efficiency, versatility, and minimal maintenance needs. The performance of a cyclone separator is influenced by factors such as particle properties, inlet velocity, and the geometric design of the cyclone.
Cyclonite – It is also known as RDX (Research Department Explosive or Royal Demolition Explosive) or hexogen, is a white crystalline solid and a powerful explosive. It’s a synthetic chemical compound, not found naturally, with the chemical name hexahydro-1,3,5-trinitro-1,3,5-triazine. RDX is a key ingredient in different explosives, including those used in industrial, and mining applications.
Cyclopentadiene – It is a cyclic, unsaturated hydrocarbon with the chemical formula C5H6. It is a colourless liquid with a strong, unpleasant odour. Cyclopentadiene is used in the production of plastics, insecticides, and other chemicals. It’s also a precursor to metallocenes, which are used as catalysts.
Cyclo-pentane – It is a cyclo-alkane with five-carbon ring shaped like a pentagon. Cyclo-pentane is a clear, highly flammable liquid hydro-carbon with the chemical formula C5H10, featuring a ring structure of five carbon atoms. It is a colourless liquid with a petrol or gasoline-like odour. Its boiling point is 49 deg C and melting point / freezing point -94 deg C.
Cyclo-propane – It is the smallest cyclo-alkane, forming a three-carbon triangle. It is a flammable, colourless gas with the chemical formula C3H6, consisting of three carbon atoms linked in a small triangular ring. The tight 60-degree bond angles in the triangular ring force a strong deviation from normal carbon bond angles, creating heavy angle and torsional strain. Because of this high ring strain, cyclo-propane is unstable and reacts easily, frequently opening its ring in chemical reactions much like an alkene. It is a gas at room temperature and is typically stored under pressure as a liquid.
Cyclotron – It is a compact type of particle accelerator which uses a constant magnetic field to bend charged particles into a circular orbit and an alternating electric field to speed them up in an outward spiral.
Cyclotron resonance – It is the maximum absorption of electro-magnetic energy by charged carriers (like electrons or ions) when an applied alternating electric field frequency matches their natural circular gyration frequency in a static magnetic field.
Cylinder – It is a rigid, hollow or solid circular structure designed to house moving components, guide fluid flow, or contain high-pressure gases and liquids. A cylinder, in the context of pressurized containment, refers to a long, cylindrical container, typically with a circular cross-section, designed to store gases under pressure. It is also the chamber of a piston actuator in which the piston moves. Cylinders are a subset of pressure vessels but have a specific shape and purpose. In cylinders, the motive force for a pneumatic or hydraulic actuator is generated by a plunger or piston being pressurized inside a cylindrical housing.
Cylinder block – It is the largest and heaviest component of an engine, serving as its backbone and housing the cylinders, coolant passages, and exhaust passages, with different engine components bolted directly to it. It typically comprises materials like gray cast iron or compacted graphite iron, which provide necessary and thermal properties for durability and efficiency.
Cylinder bore – It is the internal diameter of a cylindrical barrel or combustion chamber in which a piston reciprocates (moves back and forth).
Cylinder closure seal – It is the sealing element at the connection of the piston actuator cylinder to the yoke.
Cylinder configuration – It refers to the structural arrangement and layout of the cylinders in a reciprocating internal combustion engine. This layout defines how the cylinders are positioned relative to each other and the crankshaft, directly impacting the engine’s balance, packaging size, cost, and performance characteristics.
Cylinder deactivation – It is an engine management technology which temporarily shuts off a specific number of cylinders when full power is not needed, effectively reducing engine displacement to save fuel and lower emissions.
Cylinder flow – It refers to the movement of air-fuel mixtures within the combustion chamber of an internal combustion engine, influenced by factors such as the design of the intake manifold, cylinder head shape, and piston crown, which facilitate specific flow patterns like tumble or swirl before the combustion stroke.
Cylinder head – It is an upper engine component bolted onto the top of an engine block which seals the upper end of the cylinders to form the combustion chambers.
Cylinder motion – It refers to the physical displacement, rotation, or fluid dynamics associated with a cylindrical component, actuator, or internal chamber.
Cylinder mould machine – It is a specialized industrial papermaking machine which forms paper or paper-board sheets by partially submerging a rotating wire-mesh cylinder (the mould) into a vat filled with a pulp-and-water slurry.
Cylinder pairs – These refer to two cylinders whose dynamic behaviour is influenced by their spatial configuration relative to the flow, leading to different types of vibration excitation, such as in-line and transverse vibrations, depending on their proximity and the resulting vortex shedding effects.
Cylinder pressure – It is the pressure generated within the combustion chamber of an engine during its operating cycles, influenced by factors such as ignition delay and the combustion mixture.
Cylinder rotation – It refers to the motion of a cylinder around its axis, which influences fluid flow and can lead to the formation of vortices, such as Taylor vortices, under certain conditions. This phenomenon affects drag and lift forces, making it applicable in different engineering scenarios.
Cylinder surface – It is the outer boundary of a cylinder, parameterized by points on the surface using a centre-point, radius, and height of the cylinder.
Cylinder variation – It is frequently referred to as cylinder-to-cylinder variation or imbalance. It refers to the performance, geometric, or operational differences between individual cylinders within a multi-cylinder internal combustion engine or reciprocating compressor. In an ideal engine, every cylinder behaves identically. In reality, manufacturing tolerances, thermal differences, and fluid dynamics cause each cylinder to produce slightly different levels of power, emissions, and stress.
Cylinder wall – It is the inner guiding surface of a cylinder in an engine, pump, or pressure vessel. It constrains and guides the reciprocating movement of the piston. It forms a tight seal with the piston rings, riding on a thin film of lubricating oil, to contain high-pressure gases and prevent blow-by. It absorbs heat from the combustion process and conducts it away to engine coolant or cooling fins. It features a precision-honed crosshatch pattern (typically 40-degree to 50-degree) to trap microscopic quantities of oil, reduce friction, and allow the piston rings to seat properly. It is typically cast from high-strength cast iron or aluminum, sometimes using specialized dry or wet cylinder liners and coatings.
Cylindrical axis – It refers to the central, straight line of symmetry running through the core of a cylindrical object, system, or coordinate framework. It refers to the central line of symmetry in a cylindrical resonator, around which the geometry of the resonator is defined and symmetric properties are established.
Cylindrical coordinates – The coordinates ‘r’, theta, and ‘z’ describe the motion of a point ‘P’ in the ‘x, y, z’ space. The cylindrical coordinates ‘r’ and theta are the polar coordinates of ‘P’ measured in the plane parallel to the ‘x-y’ plane. The coordinate ‘z’ measures the position of the point ‘P’ perpendicular to the ‘x-y’ plane. Cylindrical coordinates uses the distance ‘d’ from the z-axis, the azimuthal angle theta, and the vertical coordinate ’z’ to specify points in three-dimensional space.
Cylindrical coordinate system – It is a three-dimensional system which locates a point in space using three parameters namely radial distance (r) which is the shortest perpendicular distance from the central z-axis to the point, azimuthal angle (theta) which is the rotation angle measured in the horizontal plane from a reference axis (normally the positive x-axis to the radial line, and axial height (z) which is the standard Cartesian height or signed distance along the central z-axis.
Cylindrical components – These are physical parts or mathematical elements shaped like a tube or cylinder, featuring a round cross-section and a straight central axis.
Cylindrical die – it is a round, roller-like tool with an engraved or threaded surface used in cold-forming or rotary die-cutting processes to shape, thread, or cut materials under high pressure.
Cylindrical-die infeed thread rolling machine – It is a cold-forming industrial metal-working device which uses two or three rotating round dies to plunge radially inward and press precise screw threads or profiles into a stationary, rotating work-piece.
Cylindrical-die machine – It is frequently referred to as a cylindrical die-rolling or rotary die-cutting machine. It is an industrial manufacturing system which uses two or more round, rotating roller dies to shape, thread, or cut materials through continuous mechanical contact.
Cylindrical-die rolling – It is a cold-forming metal-working process which uses two or three rotating round dies to press profiles, such as screw threads or gears, into a cylindrical metal blank without cutting away any material.
Cylindrical duct – It is also called circular duct /round duct. It is a tubular conduit with a constant circular cross-section used to transport fluids, gases, air, or acoustic waves.
Cylindrical external receiver – An external cylindrical receiver is defined as a type of solar energy receiver which utilizes a cylindrical structure to maintain a moderate performance for solar energy absorption, especially as the sun’s azimuth changes throughout the day. This design allows for a surrounding field which helps to average the cosine effect of sunlight incidence, improving annual performance compared to other receiver types.
Cylindrical furnace – It is a thermal heating system designed with a radially symmetrical, tube-shaped or barrel-shaped chamber. Its geometry optimizes uniform heat distribution, manages intense thermal loads, and minimizes structural warping under extreme temperatures.
Cylindrical gear – It is a toothed mechanical component whose pitch surface (and typically its outside diameter) forms a cylinder of constant radius, with its geometric axis coinciding with the gear’s axis of rotation. These gears are mainly designed to transmit motion, torque, and power between parallel shafts. Unlike bevel or worm gears, the teeth are cut around a cylindrical base shape. The contact point between meshing teeth lies on the line of centres, determining the smooth transmission ratio and mechanical advantage.
Cylindrical grinding – It is grinding the outer cylindrical surface of a rotating part.
Cylindrical interface – It typically refers to a contact boundary, fluid meniscus, or multi-phase separation surface which takes the shape of a cylinder or a portion of one.
Cylindrical joint – it is a two-degree-of-freedom kinematic pair in mechanical engineering which connects two rigid bodies while restricting their relative motion to a single common axis.
Cylindrical land – It is the land having zero relief.
Cylindrical mandrel – It is a cylindrical tool used in bending tests to assess the resistance of coatings to cracking and detachment when subjected to bending around it.
Cylinder manifold – It is a multiple header for inter-connection of gas or fluid sources with distribution points.
Cylindrical membrane – It refers to a thin-walled, tube-shaped structural or functional element which resists applied loads (such as internal pressure, external pressure, or fluid drag) mainly through in-plane membrane (axial and hoop / circumferential) stresses rather than bending stiffness.
Cylindrical micelle – It is an elongated, flexible, worm-like colloidal aggregate formed by the spontaneous self-assembly of amphiphilic molecules (such as surfactants or block copolymers) in a solvent. Cylindrical micelles are elongated, flexible aggregates formed from surfactant molecules, typically occurring when the packing parameter is between 1/3 and 1/2, leading to a uniaxial growth from smaller spherical micelles into a uniform cylindrical shape.
Cylindrical probe – It is a slender, rod-shaped or circular-bodied measuring, sensing, or testing instrument designed to interface with a component, material, or fluid.
Cylindrical reservoir – It is a fluid storage structure with a circular cross-section and uniform vertical or horizontal walls, designed to safely contain, manage, and distribute liquids or gases under specific pressure conditions.
Cylindrical rod – It is a long, solid (or sometimes hollow) circular-profile structural or mechanical component designed to transmit forces, guide linear motion, or transfer rotational energy.
Cylindrical roller bearing – It is a type of rolling-element mechanical component which uses cylinders as its rolling elements. Unlike ball bearings, which make point contact with their raceways, cylindrical roller bearings make line contact.
Cylindrical section – It is a straight, tube-like structural or geometric component with a constant circular cross-section, a uniform radius (r), and a defined height or length (h).
Cylindrical shape – It is a three-dimensional geometric structure defined by two parallel, identical circular bases connected by a continuous curved lateral surface.
Cylindrical shell – It is a three-dimensional structural or mechanical element with a curved surface whose wall thickness is small compared to its radius and length. It is formed by revolving a straight line (generator) around a parallel axis, creating a closed tubular body.
Cylindrical structures – These structures refer to objects with a cylindrical shape which are normally used in different industries, such as wind turbine towers, and are frequently subjected to harsh environmental conditions which can lead to defects like surface cracks.
Cylindrical tank – It is a closed, hollow container with a circular cross-section and two parallel circular end caps (flat, domed, hemispherical, or dished) used to store or transport liquids and gases.
Cylindrical trough collector – It is frequently referred to interchangeably as a cylindrical parabolic concentrator or parabolic trough collector. It is a type of linear-focusing solar thermal device which uses a curved, trough-shaped reflector to concentrate incident sunlight onto a central receiver tube.
Cylindrical tube – It is a long, hollow, axisymmetric structural or mechanical component characterized by a circular cross-section and parallel inner and outer walls.
Cylindrical vertical melting furnace – It is a tall, tube-shaped industrial unit built upright to liquefy metals or ores. Raw materials like scrap metal, coke, and flux enter from the top while heat rises or blasts through the bottom, allowing molten liquid to pool at the base.
Cylindrical vessel – It is a tubular container with a circular cross-section and closed ends, used to hold fluids or gases under operational pressures.
Cylindrical wave – It is a wave which radiates outward from a uniform line source (such as an idealized infinite line current or a narrow slit), producing concentric, expanding cylindrical wave-fronts.
Cymbal transducer – It is defined as a device which consists of two metal end caps enclosing a piezo-electric ceramic disk, which generates an electric field when subjected to vertical load, improving displacement and reducing stress concentration.
Czochralski (CZ) method – It is an industrial crystal growth technique used to produce large, high-purity single crystals (monocrystals) from a molten material.
Czochralski process – It is a method for growing large single crystals by slowly pulling a seed crystal out of a melt, considerably impacting the production of silicon semi-conductors used in integrated circuits.
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