Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘M’
Glossary of technical terms for the use of metallurgical engineers
Terms starting with alphabet ‘M’
Maceral -It is a component, organic in origin, of coal or oil shale. The term ‘maceral’ in reference to coal is analogous to the use of the term ‘mineral’ in reference to igneous or metamorphic rocks. Examples of macerals are inertinite, vitrinite, and liptinite.
Maceral analysis – Maceral analysis is important parameter since vitrinite and exinite are more reactive than the other species of coal. Maceral analysis is obtained by the microscopic examination of coal and is a volumetric distribution of macerals in a coal sample. Fine coal (not pulverized) is set into a small block of epoxy type material and one face is polished. A number of different points on the polished face (normally at least 500) are examined by the microscope and the maceral species observed are recorded. The maceral is the result of these observations presented in percentage.
Maceral components – These are the individual organic constituents found within coal and other organic-rich sedimentary rocks, identified mainly by their morphology and optical properties under a microscope. They are the organic equivalent of minerals in inorganic rocks, but unlike minerals, they do not have a fixed chemical composition or crystalline structure. Macerals are derived from specific plant materials (such as wood, bark, spores, or leaves) which have undergone chemical and physical transformation (coalification) over geological time. Their properties and behaviour during industrial processes (like combustion or coking) are key factors in determining coal quality and use.
Maceral composition – It refers to the relative proportions of the different types of organic matter constituents, known as macerals, found within a coal or other organic-rich sedimentary rock. Macerals are the organic equivalents of minerals in inorganic rocks and are classified based on their distinct botanical origin, morphology, and optical properties observed under a microscope. Macerals are categorized into three main groups, each with specific characteristics and origins namely vitrinite (or huminite in low-rank coals), liptinite (formerly exinite), and inertinite.
Maceral group – It is a basic category of organic matter in coal, classified based on its chemical composition, optical properties, and origin from ancient plant material. The three main maceral groups are vitrinite, liptinite, and inertinite. Coal petrographers use these groups to understand and utilize coal by examining its properties under a microscope.
Macerate – It means to chop or shred fabric for use as a filler for a moulding resin.
Mach – It is a measurement of speed. It is defined as the ratio of an object’s speed to the speed of sound in the surrounding medium. Hence, Mach 1 is equivalent to the speed of sound. The ‘Mach number’ indicates how many times faster an object is moving than the speed of sound.
Mach angle (mu) = It is half of the vertex angle of the Mach cone, which is formed by a supersonic object moving through a fluid. It is defined by the formula Sin (mu) = 1/M, where ‘M’ is the Mach number (the ratio of the object’s velocity to the speed of sound). The Mach cone represents the region where pressure disturbances travel, and the angle determines how far ahead of the object these disturbances are heard or seen.
Mach cone – It is the conical shape formed by shock waves created by an object moving through a medium, like air, at supersonic speeds (faster than the speed of sound). The object ‘outruns’ the pressure waves it generates, causing them to accumulate and form a cone-shaped shock wave. The visible result of this is frequently the sonic boom, heard when the object emerges from the cone’s tip.
Machinability – It is the relative ease with which material is removed from a solid by controlled chip-forming in a machining process. It is the relative ease of machining a metal.
Machinability index – It is a relative measure of the machinability of an engineering material under specified standard conditions. It is also known as machinability rating.
Machine – It is a physical system which uses power to apply forces and control movement to perform an action. Machines can be driven by animls and people, by natural forces such as wind and water, and by chemical, thermal, or electrical power, and include a system of mechanisms which shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors which monitor performance and plan movement, frequently called mechanical systems. A simple machine is an elementary device which put a load into motion, and creates mechanical advantage which is the ratio of output force to input force. Modern machines are complex systems which consist of structural elements, mechanisms and control components and include interfaces for convenient use.
Machine accuracy – It is the degree to which a machine’s actual output matches its intended or programmed specifications. It is a measure of how closely the machine’s results, such as a manufactured part’s dimensions or a movement to a specific coordinate, align with the true or target value. A highly accurate machine consistently produces results with very little deviation from the desired outcome.
Machine allowance – It is the extra material left on a work-piece, such as a casting or forging, which is removed during subsequent machining operations to achieve the final desired dimensions, accuracy, and surface finish. This allowance accounts for imperfections in the raw material, such as surface roughness and dimensional inaccuracies, and ensures the final product is correct and functional.
Machine capacity – It refers to the maximum quantity of output a machine can produce under specific conditions within a defined time frame. It is a crucial metric for understanding a machine’s production potential and ensuring efficient operations. Calculating machine capacity involves considering several factors like operational overview, availability, performance, and utilization rates.
Machine controller – It is the central control unit which manages a machine’s operation, acting as the brain to read instructions, control its systems, and interact with the operator. It receives inputs from sensors and the user, processes them using specific logic, and sends commands to the machine’s hardware, like motors, to execute tasks and automate operations.
Machine-crafted crowned pulley – It is a pulley featuring a precisely machined crown or vertex, created through automated processes, typically computer-driven, for ensuring accurate contours and enhance performance.
Machine design – It is the process of creating, developing, and analyzing mechanical systems and components by applying engineering principles to fulfill specific tasks. It involves selecting materials, determining dimensions, and integrating different parts like gears and shafts to create functional, reliable, and cost-effective machines.
Machined notch – It is a precisely cut, V-shaped or U-shaped indentation in a material, created by a machine, which serves as a stress concentrator. These notches are used in engineering and materials testing to study material properties like fracture toughness and fatigue strength, or they are intentionally introduced in fabrication to facilitate joints, edges, and bending.
Machined profile – It is the specific shape, size, and surface contour of a component that has been created or altered by removing material using a machining process like milling, turning, or grinding. It can refer to the external outline of a part or a complex, curved surface, and the final profile is the result of a precise sequence of movements by a cutting tool guided by a computer numerical control (CNC) machine or other automated system.
Machine downtime – It is the period when a machine or piece of equipment is not operational and unavailable for production. This can be because of a planned event, such as scheduled maintenance or upgrades, or an unplanned event like a breakdown, malfunction, or operator error. Downtime represents lost productivity, delays, and reduced output, making its management crucial for operational efficiency and cost control.
Machined profile – It is the specific shape, size, and surface contour of a component which has been created or altered by removing material using a machining process like milling, turning, or grinding. It can refer to the external outline of a part or a complex, curved surface, and the final profile is the result of a precise sequence of movements by a cutting tool guided by a computer numerical control (CNC) machine or other automated system.
Machine drawing – It is an engineering drawing which serves as a blueprint for manufacturing, assembling, and maintaining a machine or its components. Machine drawings are a universal language for engineers, showing precise details like shape, size, material, and manufacturing specifications, including measurements, tolerances, and finishing requirements.
Machined springs – This type of spring is produced by machining a steel bar with a lathe and/or milling operation rather than coiling wire. Since it is machined, the spring may incorporate features in addition to the elastic element. Machined springs can be made in the typical load cases of compression / extension, and torsion etc.
Machined surface – It is the outer layer of a component which has been shaped by removing material through machining processes like milling, turning, or grinding. Its texture is defined by roughness (fine imperfections), waviness (coarser irregularities), and lay (the direction of surface patterns), which are influenced by the machining parameters, tool, and material. The desired surface finish, which impacts a part’s durability, functionality, and appearance, can range from a basic ‘as-machined’ finish to a high-quality, polished surface.
Machine element – It refers to an elementary component of a machine. These elements consist of three basic types namely (i) structural components such as frame members, bearings, axles, splines, fasteners, seals, and lubricants, (ii) mechanisms which control movement in different ways such as gear trains, belts, or chain drives, linkages, cam and follower systems, including brakes and clutches, and (iii) control components such as buttons, switches, indicators, sensors, actuators and computer controllers. While normally not considered to be a machine element, the shape, texture and colour of covers are an important part of a machine which provide a styling and operational interface between the mechanical components of a machine and its users.
Machine finish – It is the surface texture of a machined part which results directly from a mechanical manufacturing process, such as CNC (computer numerical control) machining, without subsequent polishing or coating. For machined parts, this finish frequently has visible tool marks and can range from rough to very smooth, depending on the tools and settings used, but it is less polished than a final, post-processed finish.
Machine forging – It is the forging which is performed in upsetters or horizontal forging machines.
Machine interface – It is a system which enables human interaction with machines, software, or other devices. The most common type is a Human-Machine Interface (HMI), which uses a combination of hardware (like touchscreens, buttons, or keyboards) and software (like graphical displays) to allow users to monitor, control, and view information from a machine or system.
Machine language – It is a low-level programming language consisting of binary code, which is directly understood and executed by a computer’s central processing unit (CPU). It represents the most basic level of machine instructions, where each combination of bits corresponds to a specific operation, such as adding numbers or moving data. Since it is difficult for humans to read and write, higher-level languages have been created to be more user-friendly.
Machine learning – It is the set of artificial intelligence techniques for systems which can follow examples to solve new problems.
Machine rate – It is the estimated cost of operating a machine on an hourly basis, calculated by dividing the total factory overhead expenses associated with a machine by the number of hours it has been in operation. It is a method of allocating overhead costs to production, especially in industries where machinery is a primary driver of costs. This hourly cost includes both fixed costs (like rent, insurance, and depreciation) and variable costs (like power and consumables).
Machine reference planes – These planes are designated flat surfaces which are used as a basis for measurements, positioning, and defining geometry within a machine or a part. These planes act as a zero point or a datum for dimensions and relationships between different elements of the machine or work-piece. These planes are necessary for ensuring accuracy and consistency in machining operations and assembly.
Machinery area – It is a designated space containing the machinery and equipment which power a facility, or a system. This can include the engine room, boiler room, and areas with generators, pumps, and other mechanical equipment.
Machinery component – It is an individual part of a machine which performs a specific function to enable the overall operation of the machine. These components are the fundamental building blocks of any mechanical system and are designed to convert, transmit, or control motion and power. Examples include gears, shafts, bearings, levers, and fasteners.
Machine shop drawing – This drawing frequently gives only the information necessary for machining.
Machine shop turnings – This type of scrap constitutes clean steel or wrought iron turnings, free of iron borings, non-ferrous metals in a free-state, scale, or excessive oil. It cannot include badly rusted or corroded stock.
Machine shop turning and iron borings – These are the same as machine shop turnings but include iron borings.
Machine structure – It is the load-bearing framework of a machine which holds its components in place, ensuring stability and precision during operation. It withstands static and dynamic forces to prevent deformation and vibration, which is crucial for maintaining accuracy in tasks like machining. Key functions include providing support, constraining movement, and providing the necessary stiffness and damping properties to meet performance requirements.
Machine-to-machine (M2M) communication – It is a technology which allows devices to exchange data and perform actions without human intervention, using either wired or wireless communication channels. This is achieved by sensors collecting data, communication networks transmitting it, and processing units analyzing it to enable autonomous decision-making and task execution.
Machine tool – It is a machine for handling or machining metal or other rigid materials, normally by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools use some sort of tool which does the cutting or shaping. All machine tools have some means of constraining the work-piece and provide a guided movement of the parts of the machine. Hence, the relative movement between the work-piece and the cutting tool (which is called the toolpath) is controlled or constrained by the machine to at least some extent, rather than being entirely ‘offhand” or ‘freehand’. It is a power-driven metal cutting machine which assists in managing the needed relative motion between cutting tool and the job which changes the size and shape of the job material.
Machine vision – Machine vision has emerged as an important new technique for industrial inspection and quality control. When properly applied, machine vision can provide accurate and inexpensive inspection of workpieces, hence dramatically increasing product quality. Machine vision is also used as an in-process gauging tool for controlling the process and correcting trends which can lead to the production of defective parts. Some of the industries such as the automotive and electronics industries make heavy use of machine vision for automated high volume, labour intensive, and repetitive inspection operations. This ability to acquire an image, analyze it, and then make an appropriate decision is very useful in inspection and quality control applications. Machine vision enables it to be used for a variety of functions, including (i)identification of shapes, (ii) measurement of distances and ranges, (iii) gauging of sizes and dimensions, (iv) determining orientation of parts, (v) quantifying motion, and (vi) detecting surface shading. These capabilities allow users to employ machine vision systems for cost-effective and reliable 100 % inspection of workpieces.
Machine welding – It is welding with equipment which performs the welding operation under the constant observation and control of a welding operator. The equipment may or may not load and unload the work-piece.
Machining – It is removing material from a metal part, usually using a cutting tool, and normally using a power-driven machine.
Machining allowance – It is the quantity of excess metal surrounding the intended final configuration of a formed part which is sometimes called forging envelope, finish allowance, or cleanup allowance. It is also the quantity of stock left on the surface of a casting for machining.
Machining damage – It consists of irregularities or changes on the surface of a material because of the machining or grinding operations which can deleteriously affect the performance of the material / part.
Machining force – It is the sum of the interacting forces between a work-piece and the cutting tool during a machining operation, encompassing cutting, axial, and radial forces. These forces, which are important for determining power requirements, work-piece accuracy, and tool wear, result from the friction and deformation of the material as it is being cut.
Machining parameters – These are the variables which control a machining operation, including the cutting speed, feed rate, and depth of cut. These settings are important since they directly influence the outcome of the process, affecting factors like manufacturing time, surface finish, tool wear, and overall cost. Proper selection and adjustment are important for achieving the desired quality and efficiency.
Machining performance – It is the measure of how effectively a machining process is carried out, evaluated by metrics such as tool life, cutting force, and surface finish. It is a complex system-level assessment which balances factors like productivity, cost, and part quality, which are influenced by the work-piece material, tool material, and process parameters (speed, feed, depth of cut).
Machining screw (MS) grade ferro-manganese (Fe-Mn) – It contains 80 % to 85 % of manganese, 0.35 % of silicon, and 1.25 % to 1.50 % carbon. This low silicon ferro-manganese alloy is developed to add during production of free machining screw steels.
Machining stress – It is the residual stress caused by machining.
Machining tears – Machining tears result from the use of machining tools having dull or chipped cutting edges. Such discontinuities serve as stress raisers and can lead to premature failure of a component especially when it is subjected to fatigue loading.
Mach number – It is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound, i.e., M= u/c where ‘M’ is the local Mach number, ‘u’ is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and ‘c’ is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature. By definition, at Mach 1, the local flow velocity ‘u’ is equal to the speed of sound. At Mach 0.7, ‘u’ is 70 % of the speed of sound (sub-sonic), and, at Mach 1.45, ‘u’ is 45 % faster than the speed of sound (super-sonic). The local speed of sound, and hence the Mach number, depends on the temperature of the surrounding gas. The Mach number is mainly used to determine the approximation with which a flow can be treated as an incompressible flow. The medium can be a gas or a liquid.
Mach-Zehnder interferometer – It is an optical arrangement which utilizes two parallel light beams, produced by a beam splitter, to visualize high-speed flows by creating interference fringes through phase differences in the recombined light after passing through a test section.
Macro – In relation to composites, it denotes the gross properties of a composite as a structural element but does not consider the individual properties or identity of the constituents.
Macro-cell – It refers to a measure of corrosion activity occurring between a corroding anode and a passive cathode, specifically quantifying the current associated with the reduction process at the cathode, while excluding the self-corrosion of the anode.
Macro-emulsions – Macro-emulsions (sometimes called as ‘soluble oils’) contain an oil-based lubricant, such as a mineral or compounded oil in the form of suspended droplets, which have been dispersed with the aid of special chemical agents called emulsifiers. The emulsified oil droplets are large enough to make the made up lubricant milky (or sometimes translucent) in appearance. The action of emulsions as lubricants can be close to that of the dispersed phase. Emulsions can also be formulated to include higher levels of extreme pressure agents or barrier films (polymers, and fats etc.) for heavy-duty operations. Macro-emulsions are usually milky white in appearance. They are normally used in heavy-duty metal working processes like roll forming of structural members, shelving, automotive, and furniture components.
Macro-etching– It means etching a metal surface to accentuate gross structural details, such as grain flow, segregation, porosity, or cracks, for observation by the unaided eye or at magnifications to 25×.
Macro-etch test – It is a test in which the sample is prepared with a fine finish and etched to give a clear definition of the weld.
Macro-etch testing – Soundness and homogeneity of alloy steel wire rods are sometimes evaluated macroscopically by examining a properly prepared cross section of the product after it has been immersed in a hot acid solution. It is customary to use hydrochloric acid for this purpose.
Macrograph – It is a graphic representation of the surface of a prepared sample at a magnification not exceeding 25×. When photographed, the reproduction is known as a photo macrograph.
Macro-hardness test – It is a term applied to such hardness testing procedures as the Rockwell or Brinell hardness tests to distinguish them from micro-indentation hardness tests such as the Knoop or Vickers hardness tests.
Macro-molecular crystal – It is a crystalline solid where the lattice is formed by billions of large molecules, arranged in a periodic array. Unlike small molecule crystals, which are frequently hard and rigid, macro=molecular crystals are frequently soft, with a liquid phase (mainly water) occupying a substantial portion of the crystal volume (30 % to 80 %). This liquid is necessary for preserving the crystal’s order.
Macro particle – It is a physical particle in a plasma which is large compared to ions and electrons, frequently generated during processes like cathodic arc deposition.
Macro-pore – It consists of pores in pressed or sintered compacts which are visible with the naked eye.
Macro-scale – It refers to a level of analysis or design which deals with phenomena, structures, or systems that are large enough to be observed and measured with the unaided eye. This approach focuses on overall, average, or bulk properties and behaviour, rather than the fine details of individual components or micro-level processes.
Macroscopic – It means visible at magnifications to 25×.
Macroscopic behaviour – It describes the large-scale, observable characteristics of a system, such as its overall flow, pressure, volume, and temperature. It focuses on the bulk properties of matter without considering the actions of individual atoms or molecules. For example, analyzing the stress-strain behaviour of a metal or the expansion of a gas are examples of macroscopic analysis, which is necessary for most classical engineering applications.
Macroscopic particles – These are large particles, typically larger than atoms and molecules, which can be seen with the naked eye. Their behaviour is studied using classical mechanics, and their properties, like volume and temperature, are considered without analyzing the motion of individual constituent atoms. Examples include grains of sand, and water droplets.
Macroscopic stresses – These are also called macro-stresses. These extend over distances which are large relative to the grain size of the material, are of general interest in design and failure analysis. Macro-stresses are tensor quantities, with magnitudes varying with direction at a single point in a body. The macro-stress for a given location and direction is determined by measuring the strain in that direction at a single point. When macro-stresses are determined in at least three known directions, and a condition of plane stress is assumed, the three stresses can be combined using Mohr’s circle for stress to
determine the maximum and minimum residual stresses, the maximum shear stress, and their orientation relative to a reference direction. Macro-stresses strain many crystals uniformly in the surface. This uniform distortion of the crystal lattice shifts the angular position of the diffraction peak selected for residual stress measurement. Macro-stresses can be determined from the X-ray diffraction-peak position and breadth. Macroscopic stress is the residual stress in a material in a distance comparable to the gauge length of strain measurement devices (as opposed to stresses within very small, specific regions, such as individual grains).
Macro-segregation – All metallic materials contain solute elements or impurities which are randomly distributed during solidification. The variable distribution of chemical composition on the macroscopic level is called macro-segregation. Since macro-segregations normally deteriorate the physical and chemical properties of materials, they are to be kept to a minimum.
Macro-shrinkage – It consists of isolated, clustered, or inter-connected voids in a casting which are detectable macroscopically. Such voids are normally associated with abrupt changes in section size and are caused by feeding that is insufficient to compensate for solidification shrinkage.
Macro-slip – It is a type of sliding in which all points on one side of the interface are moving relatively to those on the other side in a direction parallel to the interface. The term macro-slip is sometimes used to denote macro-slip velocity. However, this usage is not recommended.
Macro-strain – It is the mean strain over any finite gauge length of measurement large in comparison with inter-atomic distances. Macro-strain can be measured by several methods, including electrical-resistance strain gauges and mechanical or optical extensometers. Elastic macro-strain can be measured by X-ray diffraction.
Macro-structure – It is the structure of metals as revealed by macroscopic examination of the etched surface of a polished sample.
Macro voids – These are large, visible voids which form in materials like composites, membranes, and concrete because of the issues during manufacturing or construction. They can be caused by factors such as incomplete impregnation of fibres with resin, insufficient pressure, trapped gases, or improper solidification processes, and are frequently considered defects which compromise a material’s strength and integrity.
Mafic – It consists of igneous rocks composed mostly of dark, iron-rich and magnesium-rich minerals.
Magma – It is the molten material deep in the earth from which rocks are formed.
Magmatic segregation – It is an ore-forming process whereby valuable minerals are concentrated by settling out of a cooling magma.
Magmatogene deposits – The magmatogene deposits of iron ore are sub-divided into magmatic, contact-eta-metasomatic (or skarn deposit), and hydro-thermal deposits. Magmatic deposits include dike-shaped, irregular, and sheet-like titano-magnetite deposits associated with gabbro-pyroxenite rock, and apatite-magnetite deposits associated with syenites and syenite-diorites. Contact-metasomatic, or skarn, deposit form at contacts or near intrusive masses, surrounding carbonate and other type of rock which are changed by high temperature solutions into skarns, as well as scapolite and pyroxene-abilitic rock in which massive and impregnation magnetite ore deposits of complex shape remain separate. Hydro-thermal deposits form upon the action of hot mineralized solutions in cases of the deposition of iron ore in cracks and zones of crumpling, as well as in cases of metasomatic replacement of wall rocks.
Magnaflux – It is the trade name for a method of magnetic crack detection.
Magnaflux inspection – It is also known as magnetic particle inspection (MPI). It is a non-destructive testing (NDT) method used to detect surface and near-surface flaws in ferromagnetic materials like iron and steel. It works by magnetizing the material and then applying magnetic particles, which cluster around any defects because of the flux leakage, making them visible.
Magnaglo – It is the trade name for a method of magnetic crack detection in which the magnetic particles are treated so that they fluoresce in ultra-violet light.
Magnesia – It is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium. It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2- ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water, but it can be reversed by heating it to remove moisture. Magnesia is magnesium oxide produced by calcination of naturally occurring or synthetic magnesium carbonate or hydroxide and used as a raw material, normally in the dead-burned state. Naturally occurring carbonate rock is termed ‘magnesite’ which is sometimes incorrectly used to describe the calcined product.
Magnesia-carbon (MgO-C) refractory – It is the refractory which is composed predominantly of magnesia and between 7 % and 50 % by mass of residual carbon. It is important and widely used refractory in the steelmaking. It is characterized by a reduced slag infiltration depth and a high thermal shock resistance due to its carbon content. Applications of this refractory not only include wear linings in basic oxygen furnace (BOF), electric arc furnace (EAF), and steel ladle, but also functional products such as purging and taphole bricks. The success of the use of basic magnesia-carbon refractory in the steelmaking is based on its good properties of resistance to erosion, corrosion, and thermal shock.
Magnesia chromite refractory It is the refractory which is composed largely of magnesia and chromite in which the magnesia is the predominate component by mass. ISO 10081-2 contains compositional data on magnesia chromite refractories.
Magnesia-doloma (MgO-CaO) refractories – These refractories are composed largely of magnesia and doloma in which the magnesia predominates by mass (50 % MgO to 80 % MgO). These refractories are produced in different ways. Because of these refractories showing a good chemical resistance against basic environments (as slag and fluxes) at high-temperature, good thermal shock resistance, low vapour pressure, thermodynamic stability in the presence of carbon, and a suitable abrasion resistance, magnesia-doloma refractories are widely used in ferrous, non-ferrous and cement industries. However, in spite of these advantageous properties, the application of these refractory bricks has not been popular because of their tendency to hydration when exposed to the atmosphere. ISO 10081-2 contains compositional data on magnesia doloma refractories.
Magnesia refractory – It is the refractory which contains higher than 80 % by mass of magnesium oxide. ISO 10081-2 contains compositional data on magnesia refractories.
Magnesia spinel refractory – It is a refractory composed predominantly of magnesia and spinel (MgAl2O4) containing higher than or equal to 20 % by mass of magnesium oxide. ISO 10081-2 contains compositional data on magnesia spinel refractories.
Magnesite – It refer to the naturally occurring magnesium carbonate mineral. In refractory terms it is used to refer to the high temperature product magnesia (periclase). There are three general grades of magnesite produced from natural magnesite (MgCO3) and magnesium hydroxide [Mg(OH)2] obtained from sea water or from brine deposits. These are dead burnt magnesite, seawater / brine magnesite, and fused magnesite. The three types of magnesite described above are used in a variety of refractory applications. Dead burnt magnesite is mostly used in the manufacture of basic monolithics such as gunning repair products, tundish working linings and precast shapes (tundish dams/weirs). Magnesia spinel bricks are produces with the addition of small amounts of alumina to improve thermal shock resistance. Fused magnesite tends to have superior properties to sintered magnesite and as such is incorporated into refractory products used in high wear areas such as slag lines etc.
Magnesite carbon bricks – These bricks contain 8 % to 30 % carbon. Bricks with carbon content 10 % to 20 % are more common. In magnesite carbon bricks, the high carbon content is achieved by adding flake graphite. The high oxidation resistance of flake graphite contributes to the reduced erosion rates of these bricks. In addition, the flake graphite results in very high thermal conductivities compared to most refractories. These high thermal conductivities are a factor in the excellent spalling resistance of the magnesite carbon bricks. By reducing the temperature gradient through a brick, the high thermal conductivities reduce the thermal stresses within the brick. High thermal conductivity also results in faster cooling of the brick between heats and thus reduces potential for oxidation. These days magnesite carbon bricks are made with good slag resistance and hot stability. A high degree of slag resistance and good high temperature stability have been found to be advantageous in the hotter and more corrosive service environments. High temperature stability of magnesite carbon bricks is achieved by utilization of high purity graphite and magnesite.
Magnesite chrome and chrome magnesite bricks – The reaction between chrome ore and magnesite outline the fundamental chemistry of the magnesite chrome bricks. Magnesite chrome bricks can be either silicate bonded or direct bonded. Silicate bonded bricks have a thin film of silicate minerals that surrounds and bonds together the magnesite and chrome ore particles. Direct bonded bricks have the direct attachment of the magnesia to the chrome ore without intervening films of silicate. Direct bonding is obtained by combining high purity chrome ores and magnesites and firing them at extremely high temperatures. Direct bonded bricks have high strength at elevated temperatures, better slag resistance and better resistance to peel spalling than silicate bonded bricks. The balance of properties of the bricks is a function of the magnesite to chrome ratio.
Magnesite refractories – Magnesite refractories are chemically basic refractories containing at least 85 % magnesium oxide. These refractories are one of the most widely used basic refractory bricks. They are manufactured either from natural occurring magnesite or sea water magnesia. Magnesite bricks are made from dead burnt magnesite. These bricks are strong and extremely durable. Their main advantage is very high slag resistance to basic slags specially lime and iron rich slags which is very important for steelmaking processes. Magnesite refractories have the properties of bearing high temperature, high refractoriness under load, and low vulnerability to attack by iron oxide and alkalis. Magnesite refractory bricks are widely used in the basic zone of metallurgical furnaces. These refractories have spalling resistance, strong abrasion and corrosion resistance, and high cold crushing strength. Physical properties of magnesite refractories are relatively poor. Magnesite bricks cannot resist thermal stock, loose strength at high temperature, and are not resistant to abrasion.
Magnesite spinel bricks – A family of magnesite spinel refractories has been developed by combining the constituent raw materials in different ways. Some magnesite spinel bricks are made by adding fine alumina to compositions composed mainly of magnesia. On firing, the fine alumina reacts with the fine magnesia in the matrix of the brick to form an in-situ spinel bond. An alternative is to add spinel grain to a composition containing magnesia. One of the principal benefits of combining spinel and magnesia is that the resulting compositions has better spalling resistance than bricks made solely with DBM. Spinel additions also lower the thermal expansion coefficient of magnesite compositions.
Magnesium -It is a chemical element. It has symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals, it occurs naturally only in combination with other elements and almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide which inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminum and is used mainly as a component in strong and lightweight alloys which contain aluminum.
Magnesium-aluminum alloys – are defined as popular non-heat treatable aluminum alloys characterized by strong, weldable properties and high corrosion resistance, frequently improved by the addition of elements such as scandium, zirconium, and chromium to improve their mechanical properties.
Magnesium aluminum silicate – It is a naturally occurring mineral obtained from silicate ores of the montmorillonite group. It is an emulsion stabilizer, thickening agent, and viscosity controller. It is a type of clay which is composed of magnesium, aluminum, and silicate minerals, and it is frequently referred to as smectite clay.
Magnesium aluminate spinel (MgAl2O4) – It is an important constituent of magnesia-based refractory materials. The melting point of magnesium aluminate spinel is 2,135 deg C. There are no natural deposits of MgAl2O4, which is, hence, normally obtained by reaction of mixtures of magnesium oxide and aluminium oxide. Commercial sintered magnesia–spinel refractory materials are divided into three categories namely magnesia rich, stoichiometric, and alumina rich.
Magnesium castings – These are components made by pouring molten magnesium alloy into a mould to solidify into a specific shape. This process is frequently done using high-pressure die casting, where the molten metal is injected into a steel die under pressure to create complex, intricate parts with high precision and an excellent strength-to-weight ratio.
Magnesium deposit – It refers to a natural geological occurrence of magnesium-containing minerals, such as magnesite (MgCO3) or dolomite (CaCO3.MgCO3), which are mined as a source for magnesium and its compounds. These deposits are commercially exploited by extracting the magnesium from minerals or from sources like seawater, brines, and salt lakes, and are crucial for producing a wide range of products from lightweight alloys to refractories.
Magnesium fluoride – Its chemical formula is MgF2. It is an inorganic salt used for its optical properties such as high transparency from ultra-violet to infrared, a low refractive index, and high hardness. It is a durable material frequently used for anti-reflective coatings on lenses and prisms, as well as a substrate for optical components and a host material for lasers. Its stability, mechanical properties, and resistance to solarization also make it suitable for applications like excimer laser optics.
Magnesium-lithium alloys – These are ultra-light metallic materials with a density lower than pure magnesium, similar to plastics, and are used in applications such as aviation, space flight, and weapon equipment to improve fuel efficiency and meet economic and environmental transportation requirements.
Magnesium-manganese alloy – It is a magnesium alloy which incorporates manganese as an alloying element, which influences its microstructure and mechanical properties, particularly through grain refinement when manganese content is increased. The alloy typically shows low solid solubility of manganese and undergoes substantial changes in microstructure during processes like hot extrusion.
Magnesium matrix composites – These are materials which consist of a magnesium matrix reinforced with fibres or particles, such as carbon nano-tubes, to improve mechanical properties like tensile strength and yield strength. The addition of specific reinforcements can considerably improve the tensile properties of magnesium composites, making them suitable for several applications.
Magnesium oxy-chloride cement – It is also known as Sorel cement. It is a high-strength, air-hardening cement made from magnesium oxide (caustic magnesia), magnesium chloride solution, and water. It is valued for its rapid setting, high early strength, fire resistance, and low thermal conductivity. However, its poor water resistance has limited its applications mainly to indoor uses like industrial flooring, and fire-proof boards, though research is ongoing to improve its water durability.
Magnesium phosphate cement – It is a rapid-setting, high-strength cementitious binder formed by the acid-base reaction between magnesium oxide and a phosphate salt like ammonium di-hydrogen phosphate. It is characterized by its fast-hardening time (10 minutes to 20 minutes at room temperature), high early strength, and excellent frost and corrosion resistance. It is mainly used for fast-track repairs, especially in cold weather, and for applications like structural reinforcement and road repairs, because of its superior bonding properties and low shrinkage compared to ordinary cement.
Magnesium potassium phosphate – It is a cementitious material formed through the acid-base reaction of magnesium oxide (MgO) and potassium di-hydrogen phosphate (KH2PO4) in an aqueous solution. The main product is a mineral called K-struvite (MgKPO4.6H2O), which gives the material its cementitious and rapid-setting properties. This compound is frequently called ‘magnesium potassium phosphate cement (MKPC) and is used for applications like rapid concrete repair, waste immobilization, and as a low-temperature setting cement.
Magnesium powder – It refers to magnesium powder particles used in processes such as selective laser melting (SLM), where their shape and size significantly impact flowability, layer density, and laser interaction during manufacturing. Spherical and uniform powders improve workability, while larger or irregular particles can hinder performance.
Magnesium-silicon – It refers to thin films composed of magnesium and silicon, specifically synthesized in several elemental compositions through combinatorial magnetron sputter deposition, showing substantial electro-chemical performance such as high capacity and retention when the magnesium content is below the Mg2Si stoichiometry ratio.
Magnesium sulphate – Its chemical formula is MgSO4. It is an inorganic chemical compound which is a salt of sulphuric acid. It is normally known as Epsom salt. It is a white, crystalline substance which is highly soluble in water and has several applications.
Magnesium tube – It is an extruded structural component made from a magnesium alloy which is used in several applications, particularly where lightweight materials are needed. These tubes are formed into specific shapes and can be used in the automotive and aerospace industries. They can also be fabricated using processes like hydroforming, which uses internal pressure to shape the tube.
Magnesium zirconate – It refers to a class of inorganic compounds composed of magnesium and zirconium. One common example is Mg2Zr5O12 (magnesium penta-zirconate), which can be synthesized and used as a catalyst in biodiesel production. Another notable example is magnesium oxide stabilized zirconia (MgO-ZrO2) ceramics, known for their high thermal stability and structural integrity. These materials have many applications in fields like catalysis, thermal barrier coatings, and advanced ceramics.
Magnesio-ferrite – It has the chemical formula MgFe2O4. It is a magnetic, black or brownish-black mineral in the spinel group. It is a magnesium iron oxide mineral, a member of the magnetite series of spinels. Magnesio-ferrite crystallizes as black metallic octahedral crystals. It is named after its chemical composition of magnesium and ferric iron. The density is 4.6 to 4.7 (average = 4.65), and the diaphaniety is opaque. It occurs as well-formed fine sized crystals or massive and granular. Its hardness is 6 to 6.5. It has a metallic luster and a dark red streak.
Magnet – It is a material or object which produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, and cobalt etc. and attracts or repels other magnets. A permanent magnet is an object made from a material which is magnetized and creates its own persistent magnetic field. Materials which can be magnetized, are also the ones which are strongly attracted to a magnet. These are called ferromagnetic (or ferrimagnetic). An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops. Frequently, the coil is wrapped around a core of ‘soft’ ferromagnetic material such as mild steel, which greatly enhances the magnetic field produced by the coil. The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. The local strength of magnetism in a material is measured by its magnetization.
Magnet arc welding process – It is a pressure welding process with an arc that is moved magnetically under shielding gas. This technology can be used to join hollow sections with wall thicknesses of up to 10 millimeters. For example, this enables you to weld steel propshafts or torsion beams for axles. A prerequisite for this pressure welding process is that conductive and fusible materials are used and the components have tubular cross-sections. Magnet arc welding is suitable for wall thicknesses of 0.7 millimeters to 10 millimeters.
Magnetherm process – It is a highly productive reduction-distillation method which utilizes a large furnace, charging alumina alongside dolomite and ferro-silicon to lower the melting point of reaction products, allowing for the removal of molten slag at high temperatures of 1,500 deg C. This process yields magnesium with a purity of about 99.8 %, while aluminum serves both as a reductant and a slagging agent.
Magnetic alignment – It is an alignment of the electron-optical axis of the electron microscope so that the image rotates around a point in the centre of the viewing screen when the current flowing through a lens is varied.
Magnetically hard alloy – It is a ferro-magnetic alloy capable of being magnetized permanently because of its ability to retain induced magnetization and magnetic poles after removal of externally applied fields, i.e., an alloy with high coercive force. The name is based on the fact that the quality of the early permanent magnets has been related to their hardness.
Magnetically soft alloy – It is a ferromagnetic alloy which becomes magnetized readily upon application of a field and which returns to practically a non-magnetic condition when the field is removed, i.e., an alloy with the properties of high magnetic permeability, low coercive force, and low magnetic hysteresis loss.
Magnetic amplifiers – These are devices which amplify power by using a controlled direct current to saturate a magnetic core, allowing small changes in input current to produce substantial variations in output load. These are characterized by their robustness, lack of moving parts, and minimal maintenance requirements.
Magnetic-analysis inspection – It is a non-destructive method of inspection to determine the existence of variations in magnetic flux in ferro-magnetic materials of constant cross section, such as can be caused by discontinuities and variations in hardness. The variations are normally indicated by a change in pattern on an oscilloscope screen.
Magnetic Barkhausen noise (MBN) – It is a phenomenon observed in ferromagnetic materials where the magnetization process occurs in a series of sudden, irreversible jumps of magnetic domain walls. These jumps, caused by changes in an applied magnetic field, generate a noise-like signal which can be detected and analyzed to assess material properties like stress, microstructure, and hardness.
Magnetic bearing – It is a type of bearing in which the force which separates the relatively moving surfaces is produced by a magnetic field. It is a bearing which supports a load using magnetic levitation. Magnetic bearings support moving parts without physical contact. For example, they are able to levitate a rotating shaft and permit relative motion with very low friction and no mechanical wear. Magnetic bearings support the highest speeds of all kinds of bearing and have no maximum relative speed. Passive magnetic bearings use permanent magnets and, hence, do not require any input power but are difficult to design. Techniques using diamagnetic materials are relatively undeveloped and strongly depend on material characteristics. As a result, majority of the magnetic bearings are active magnetic bearings, using electromagnets which require continuous power input and an active control system to keep the load stable. In a combined design, permanent magnets are often used to carry the static load and the active magnetic bearing is used when the levitated object deviates from its optimum position. Magnetic bearings typically require a back-up bearing in the case of power or control system failure. Magnetic bearings are used in several industrial applications such as electrical power generation, petroleum refinement, machine tool operation and natural gas handling.
Magnetic blowout – It is a component of a switching device which uses a magnetic field to assist in extinguishing the arc, using a permanent magnet or a coil.
Magnetic body – It is an object which can generate a magnetic field or becomes magnetized when placed in one. This can be a permanent magnet which has a constant magnetic field, or a material which becomes magnetized when subjected to an external field, such as soft magnetic materials. The magnetic body creates a magnetic field around it, and is acted upon by forces and torques within external fields.
Magnetic bridge eliminator – This type of instrument compares variations in a test part to conditions in a known sample. When a metal part is placed inside or near a test coil which is excited by an alternating current, the voltage output from the coil is affected. This is the basic principle used by the magnetic bridge comparator. The kinds of mixes which comparators separate typically involve variations in alloy, heat treatment, hardness, structure, dimensions (including length) and certain other conditions.
Magnetic chip detector – It is an electronic instrument which attracts ferro-magnetic particles (mostly iron chips). It is mainly used in aircraft engine oil and helicopter gearbox chip detection systems. Chip detectors can provide an early warning of an impending engine failure and thus greatly reduce the cost of an engine overhaul.
Magnetic circuit – It is a closed path for magnetic flux lines to follow, typically made of high-permeability ferromagnetic materials like iron to guide and concentrate the magnetic field. It is analogous to an electric circuit, where magnetic flux is driven by a magneto-motive force (MMF) and faces opposition from reluctance. The core components are the magnetic core (the path), a winding (a coil that generates the flux), and sometimes an air gap.
Magnetic constant – It is the constant which relates the strength of magnetic flux to magnetic induction in free space.
Magnetic contrast – In electron microscopy, it is the contrast which arises from the interaction of the electrons in the beam with the magnetic fields of individual magnetic domains in ferromagnetic materials. Special instrumentation is needed for this type of work.
Magnetic conveyor – It is a specialized conveyor equipped with magnets designed for the transportation of magnetic materials. Regular inspections are essential to assess magnet strength, alignment, and overall functionality.
Magnetic core – It is a magnetic component for high frequency electronic applications made from carbonyl iron powder or ferrite powder.
Magnetic core memory – It is a type of computer memory which stores data as magnetization in tiny rings of ferrite material.
Magnetic crack detection – It is the method of locating cracks in materials which can be magnetized. It is done by applying magnetizing force and applying finely divided iron powder which then collects in the region of the crack.
Magnetic deflection – It is the bending of the path of a moving charged particle when it is acted upon by a magnetic field. This occurs because of the Lorentz force, which exerts a force on the charged particle which is perpendicular to both its velocity and the magnetic field direction, causing the particle to follow a curved or circular path. This principle is used in devices like ‘cathode ray tubes’ (CRT) to control the position of an electron beam on a screen.
Magnetic dipole moment – It is the product of the current flowing through a loop and the area of that loop, representing the strength and orientation of a magnetic dipole. For a magnetized body, it is the sum of all individual magnetic dipole moments, calculated as the product of magnetic moment and the distance between poles.
Magnetic field – It is a physical field which describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet’s magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a non-uniform magnetic field exerts minuscule forces on ‘non-magnetic’ materials by three other magnetic effects namely paramagnetism, diamagnetism, and antiferromagnetism, although these forces are normally so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, electric currents, and electric fields varying in time. Since both strength and direction of a magnetic field can vary with location, it is described mathematically by a function assigning a vector to each point of space, called a vector field (more precisely, a pseudo-vector field).
Magnetic field intensity – It is also known as magnetic field strength or magnetizing field, is a measure of the strength of a magnetic field in a material. It indicates the ability of an external magnetic field to magnetize a substance. It is defined as the force experienced by a unit north pole at any point in the magnetic field. The SI (International System of Units) unit for magnetic field intensity is Ampere per meter. Magnetic field intensity (H) is a vector quantity that describes the strength and direction of the magnetic field in a medium.
Magnetic field strength – It is a measure of the intensity of a magnetic field, frequently represented by the magnetic flux density (B) in Tesla (T) or the magnetic field intensity (H) in amperes per meter (A/m). ‘B’ represents the total magnetic field, including the effects of the source and any magnetic materials, while ‘H’ represents the magnetic field generated by external sources like electric currents alone. The strength is determined by the magnetic force it exerts on magnetic materials and moving electric charges, and is visually represented by the density of magnetic field lines, more lines mean a stronger field.
Magnetic field testing – It consists of the tests which are intended to demonstrate the immunity of equipment when subjected to power frequency magnetic fields related to the specific locations and installation condition of the equipment (e.g. proximity of equipment to the disturbance source).
Magnetic flux – It is a measure of the total number of magnetic field lines passing through a given surface area. It quantifies the quantity of a magnetic field which penetrates a surface and is calculated as the product of the magnetic field strength, the surface area, and the cosine of the angle between the field and the surface’s perpendicular line. The SI (International System of Units) unit for magnetic flux is the weber (Wb).
Magnetic flux concentrator – It is a device or material structure designed to direct, concentrate, or amplify magnetic flux from one region to another. Essentially, it focuses magnetic field lines into a specific area, intensifying the magnetic field without requiring increased input power. This is particularly useful in applications like magnetic field sensing, induction heating, and other scenarios where a stronger magnetic field is needed in a particular location.
Magnetic flux density – It is the quantity of magnetic field per unit area. It is measured in webers per square metre in SI (International System of Units) units.
Magnetic force – It is the force acting on a particle which is proportional to the strength of the magnetic field and the gradient of the particle’s location, influenced by the particle’s volume and susceptibility in the presence of an applied magnetic field.
Magnetic gradient survey – It is a geophysical survey using a pair of magnetometers a fixed distance apart, to measure the difference in the magnetic field with height above the ground.
Magnetic induction – It refers to the process by which a time-varying magnetic field induces an electric field, resulting from the interaction of velocity fields and magnetic fields, as described in the magnetic induction equation.
Magnetic lens – It is a device for focusing an electron beam using a magnetic field.
Magnetic levitation (maglev) – It is a method where an object is suspended in mid-air using only magnetic forces, without any physical support. This is achieved by counteracting gravity’s pull with the repulsive force between magnetic poles or through the interaction between magnetic fields and induced currents. Magnetic levitation is used for contactless melting, magnetic bearings, and for product display purposes.
Magnetic lifting devices – These devices are used for lifting and transporting of steel and ferrous metal stock or manufactured components. They are normally installed and used as single magnets or as arrangements of multiple magnets. In all of these cases, they are suspended from chains or wires or otherwise attached to the lifting equipment such as cranes. Electrically operated magnetic lifting devices are widely used in the iron and steel plants. Lifting magnets can be provided with no power supply, i.e., permanent magnets, or where power is supplied by cable from an external source or through an in-built battery. The magnet and any associated electrical equipment are to be designed for its intended purpose and constructed to withstand the environment in which it is required to operate. When used correctly magnetic lifting devices handle magnetic materials and components safely, and without the need for slingers.
Magnetic measurement methods – These methods involve techniques for determining the strength, direction, and other characteristics of magnetic fields and the magnetic properties of materials. These methods utilize different instruments and principles to quantify magnetic phenomena, finding applications in diverse fields. Magnetic measurement involves determining the strength (intensity), direction, and shape of magnetic fields generated by electric currents or magnetic materials. This includes measuring parameters like magnetic susceptibility, magnetization, and magnetic moment to understand how materials respond to magnetic fields.
Magnetic moment – It is the proportionality constant which relates the twisting torque produced on an object to the magnetic field.
Magnetic north – It is the direction a compass needle points, which is the direction toward the earth’s north magnetic pole, a wandering point where the magnetic field lines enter the planet vertically. This is different from true north, which is the geographic north pole where lines of longitude converge and is the centre of earth’s rotation. The two points are not fixed in the same place and move over time because of the changes in the earth’s core.
Magnetic ore – It is a type of ore which contains minerals with magnetic properties, meaning that they are attracted to a magnet. These minerals, frequently iron oxides like magnetite, can be separated from non-magnetic materials using a process called magnetic separation.
Magnetic-particle inspection – It is a non-destructive method of inspection for determining the existence and extent of surface cracks and similar imperfections in ferro-magnetic materials. Finely divided magnetic particles, applied to the magnetized part, are attracted to and outline the pattern of any magnetic leakage fields created by discontinuities. For alloy steel wire rod and wire products subject to magnetic-particle inspection, it is normal to test the product in a semi-finished form, such as billets (using samples properly machined from billets), to ensure that the heat conforms to the magnetic-particle inspection requirements, prior to further processing. The method of inspection consists of suitably magnetizing the steel and applying a prepared magnetic powder, either dry or suspended in a suitable liquid which adheres to the steel along lines of flux leakage. On properly magnetized steel, flux leakage develops along surface or sub-surface discontinuities. The results of the inspection vary with the degree of magnetization, the inspection procedure (including such conditions as relative location of surfaces tested), the method and sequence of magnetizing and applying the powder, and the interpretation.
Magnetic particle testing – It uses one or more magnetic fields to locate surface and near-surface discontinuities in ferro-magnetic materials. It is used to locate surface and slight sub-surface discontinuities or defects in ferro-magnetic materials. Such flaws present in a magnetized part cause a magnetic field, i.e. flux, to leave the part. If magnetic particles are applied to this surface, they are held in place by the flux leakage to give a visual indication. While several different methods of magnetic particle tests can be used, they all rely on this same general principle. Hence, any magnetic particle test is conducted by creating a magnetic field in a part and applying the magnetic particles to the test surface. The magnetic field can be applied with a permanent magnet or an electro-magnet.
Magnetic permeability – It is a measure of how easily a material allows a magnetic field to pass through it, or its ability to support the formation of a magnetic field within itself. It essentially indicates how well a material can be magnetized. More specifically, it is the ratio of magnetic flux density to magnetic field strength within a material.
Magnetic pole – It is the region at each end of a magnet where the external magnetic field is strongest. A bar magnet suspended in earth’s magnetic field orients itself in a north-south direction. The north-seeking pole of such a magnet, or any similar pole, is called a north magnetic pole. The south-seeking pole, or any pole similar to it, is called a south magnetic pole. Unlike poles of different magnets attract each other while the like poles repel each other. Magnetic pole is the area on a magnetized part at which the magnetic field leaves or enters the part. It is a point of maximum attraction in a magnet.
Magnetic prospecting – It is a geophysical method which uses variations in the earth’s magnetic field to explore for mineral deposits or other subsurface geological structures. By measuring anomalies caused by rocks with different magnetic properties, it can help map the depth, size, and composition of buried features, from large ore deposits to archaeological sites.
Magnetic remanence – It is the residual magnetization of a ferro-magnetic material after an external magnetic field is removed. It is the measure of the magnetism that remains in a substance, representing a form of magnetic ‘memory’ which allows for the creation of permanent magnets and the study of earth’s past magnetic field.
Magnetic resonance – It is a phenomenon in which the magnetic spin systems of certain atoms absorb electromagnetic energy at specific (resonant) natural frequencies of the system.
Magnetic seal – It is a seal which uses magnetic material, instead of springs or bellows, to provide the closing force.
Magnetic separation – Magnetic separation technologies are used to take the advantage of the difference in the magnetic properties for separating iron ore from the non-magnetic associated gangue materials. It can be conducted in either a dry or wet environment, although wet systems are more common. It is used in several flow-sheets. Magnetic separation is typically used in the beneficiation of high-grade iron ores where the dominant iron minerals are ferro and para-magnetic. Wet and dry low-intensity magnetic separation techniques are used to process ores with strong magnetic properties such as magnetite while wet high-intensity magnetic separation is used to separate the Fe-bearing minerals with weak magnetic properties such as hematite from gangue minerals. Iron ores such as goethite and limonite are normally found in tailings and does not separate very well by either technique. A full range of magnetic separators is available, from low intensity drum separators to high gradient / high intensity separators, and for either wet or dry feeds. Separation is achieved by exploiting differences in the magnetic susceptibilities of the component minerals. There are five basic types of separators designed for exploiting differences in the magnetic properties from the simplest low intensity unit for separating magnetite to high intensity / gradient units for removing minor impurities. These are (i) wet and dry, low intensity magnetic separation (LIMS), (ii) high gradient magnetic separation (HGMS), (iii) wet high intensity magnetic separation (WHIMS), (iv) roll magnetic separators for processing weak magnetic ores, and (v) induction roll magnetic separation (IRMS) for concentrating dry ores.
Magnetic seal – It is a device which uses magnetic forces for sealing, either to create a seal between a stationary and a rotating part or to hold a door closed. One type uses a magnetic fluid to form a seal in rotating shafts, while another uses permanent magnets to press two surfaces together, such as in a refrigerator door.
Magnetic separator – It is a device which is used to separate magnetic from less magnetic or non-magnetic materials. The crushed material is conveyed on a belt past a magnet.
Magnetic shielding – In electron microscopy, it is the shielding for the purpose of preventing extraneous magnetic fields from affecting the electron beam in the microscope.
Magnetic starter – It is an electrical device which not only initiates the conveyor’s motor but also provides vital overload protection. Regular checks are necessary to ensure proper motor control and protection.
Magnetic stirrer – It is a laboratory device used to mix liquids by creating a rotating magnetic field which spins a coated magnetic stir bar inside the liquid. This method provides a convenient and consistent way to mix solutions without direct mechanical contact, reducing contamination and noise compared to manual stirring with a rod.
Magnetic survey – It is a geophysical survey which measures the intensity of the earth’s magnetic field. It measures variations in the earth’s magnetic field caused by magnetic properties of subsurface rock formations. The airborne magnetometer is the primary geological tool used in the search for iron ores and iron bearing materials in large areas. The method of conducting an airborne magnetic survey is to install a flux gate or proton precision magnetometer in an airplane which traverses the target area at a fixed altitude and along predetermined flight lines. The magnetometer measures the magnitude of the earth’s magnetic field. The data is recorded electronically along with the position of the airplane and its altitude. In recent years, there is improvements in the quality of the surveys due to the refinements in the equipment that include greater sensitivity and simplicity, multiple channel data recording, miniaturization of instruments and a more accurate positioning capability. Because of the presentation and recording of the data in digital form, computers are used for carrying out the necessary data reduction and plotting requirements needed for analyses and interpretation. Data from these records are plotted as a contour map, with lines connecting points of equal magnetic intensity on the map. The patterns formed by these lines indicate areas where magnetic anomalies (major local distortions of the earth’s magnetic field) occur. The areas indicated by anomalies on the magnetic map are then investigated in greater detail by geological surveys and by gravity measurements, electromagnetic studies or other geophysical techniques.
Magnetic surveying – Magnetic survey measures variations in the earth’s magnetic field caused by magnetic properties of subsurface rock formations. The airborne magnetometer is the primary geological tool used in the search for iron ores and iron bearing materials in large areas. The method of conducting an airborne magnetic survey is to install a flux gate or proton precision magnetometer in an airplane which traverses the target area at a fixed altitude and along predetermined flight lines. The magnetometer measures the magnitude of the earth’s magnetic field. The data is recorded electronically along with the position of the airplane and its altitude. In recent years, there is improvements in the quality of the surveys because of the refinements in the equipment which include higher sensitivity and simplicity, multiple channel data recording, miniaturization of instruments and a more accurate positioning capability. Because of the presentation and recording of the data in digital form, computers are used for carrying out the necessary data reduction and plotting requirements needed for analyses and interpretation. Data from these records are plotted as a contour map, with lines connecting points of equal magnetic intensity on the map. The patterns formed by these lines indicate areas where magnetic anomalies (major local distortions of the earth’s magnetic field) occur. The areas indicated by anomalies on the magnetic map are then investigated in greater detail by geological surveys and by gravity measurements, electromagnetic studies or other geophysical techniques.
Magnetic susceptibility – It is a measure of the degree to which a rock is attracted to a magnet.
Magnetic switch – It is an electrical switch which uses a magnetic field to make or break an electrical contact. It is typically made of two parts namely a stationary switch and a magnet on a movable object, and it activates when the magnet is near the switch, completing or breaking a circuit. Common types include reed switches and Hall effect sensors, which are used for applications like security sensors, position indicators, and in keyboards.
Magnetic thickness test – Non-destructive measurement of galvanized coatings is normally done with electronic instruments which measure the distance from the surface of the coating to the steel surface which is magnetic. Any non-magnetic coating over steel can be measured with these instruments.
Magnetic test – It is the method used to test heat extraction rates of various quenchants. The test works by utilizing the change in magnetic properties of metals at their Curie point (the temperature above which metals lose their magnetism).
Magnetic transformation temperature – It is the temperature at which a material’s magnetic properties change, frequently shifting from an ordered magnetic arrangement to a disordered one. This change can be a sharp transition, like the Curie temperature for ferromagnetic materials, or a more gradual change over a temperature range.
Magnetic transformer – It is an electrical device which uses mutual induction to transfer energy between two or more circuits, typically changing the voltage and current levels. It works by converting electrical energy into a magnetic field, which is then converted back into electrical energy in a second coil. Key components include a primary winding, a secondary winding, and a magnetic core that links them, and they only operate with alternating current (AC).
Magnetism – It is the class of physical attributes which occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electro-magnetism. The most familiar effects occur in ferro–magnetic materials, which are strongly attracted by magnetic fields can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferro-magnetic. The most common ones are iron, cobalt, nickel, and their alloys.
Magnetite – It is black, magnetic iron ore, an iron oxide.
Magnetite ore – The main iron-bearing mineral of magnetite is tri-iron tetroxide, and its chemical formula is Fe3O4. The theoretical iron content is 72.36 %, the appearance colour is usually carbon black or slightly light blue black, metallic lustre, streaks (colour appearing on the board when the surface is uneven on the white porcelain plate) black. The most prominent feature of this ore is its magnetic nature, which is also the origin of its name. Magnetite contains both ferrous and ferric iron. It differs from most other iron oxides in that it contains both divalent and trivalent iron. It is generally very hard, dense in structure and poor in reducing performance. Normally, the hardness of magnetite is between 5.5 and 6.5 on Mohs scale, and the specific gravity is between 4.6 and 5.2.
Magnetization – It is a property of a material which measures its response to a magnetic field.
Magnetization current – In a transformer, it is that portion of the current which is used to support magnetic flux.
Magnetizing force – It is a force field, resulting from the flow of electric currents or from magnetized bodies, which produces magnetic induction. It is the strength of a magnetic field which is needed to magnetize a material. It quantifies how effectively a magnetic field can induce a magnetic moment in a substance, with its SI (International System of Units) unit being amperes per meter (A/m). Magnetizing force is also known as magnetic field intensity or magnetic intensity.
Magneto-crystalline anisotropy – It is the tendency of a magnetic material’s magnetization to align itself along certain preferred crystallographic directions. This directional preference is because of the interaction between the electron’s magnetic spin and the crystal lattice (spin-orbit coupling), which makes it easier for the magnetization to align with some directions (easy axes) than others (hard axes). The energy difference between these orientations is the magneto-crystalline anisotropy energy, a key property for applications like permanent magnets, which need high anisotropy to resist demagnetization.
Magneto-hydrodynamics (MHD) – It is also called magneto-fluid dynamics or hydromagnetics. It is a model of electrically conducting fluids which treats all inter-penetrating particle species together as a single continuous medium.
Magneto-hydrodynamic (MHD) generator – It is a device which converts thermal energy directly into electrical energy by passing a high-velocity, electrically conductive fluid (like ionized gas or plasma) through a magnetic field. This process generates an electric current without the need for mechanical parts like turbines, making it highly efficient and allowing for operation at higher temperatures than traditional power plants. The fundamental principle is based on Faraday’s law of induction, where the movement of the conductive fluid through the magnetic field induces an electro-motive force and a resulting electrical current.
Magneto-hydrodynamic lubrication – It is the hydrodynamic lubrication in which a considerable force contribution arises from electro-magnetic interaction. Magneto-hydrodynamic bearings have been proposed for very high-temperature operation, e.g., in liquid sodium.
Magneto-meter –Magneto-meters have passed through several successive stages of development. The principal forms as being known, in the order of their conception, are balance type, torsion type and flux gate magnetometers, followed in recent years by magneto-meters which have been conceived and developed in the field of atomic physics. These latter instruments include the rubidium vapour, proton-precession and optical absorption magneto-meters. Magneto-meters are used to determine the strength of the earth’s magnetic field or its vertical component at a given location. The earth’s field is very weak, ranging from about 0.7 oersted at magnetic poles to about 0.25 oersted at some points on the magnetic equator. In geomagnetic studies, field strength is measured in a much smaller unit than the oersted, which is the gamma (equal to 0.00001 oersted). The shape of the earth’s magnetic field is not uniform, but shows large scale regional irregularities due to variations in the shape and composition of the crust and upper mantle of the earth. Variations on a smaller scale result from magnetic disturbances caused by concentrations of magnetic material near the surface and it is these local variations that are sought when iron ores are searched.
Magneto-motive force (MMF) – It is the magnetic ‘pressure’ or force which drives magnetic flux through a magnetic circuit. Analogous to electro-motive force (EMF) in an electrical circuit, magneto-motive force is calculated by multiplying the current (I) flowing through a coil by the number of turns (N) in that coil, and its standard unit is the ampere-turn (At).
Magneto-static field – It is a static magnetic field which does not change over time, generated by steady electric currents or permanent magnets. It is the magnetic field produced in a system where all currents are constant, meaning there are no time-varying currents or induced electric fields.
Magneton – It is a unit of magnetic moment used for atomic, molecular, or nuclear magnets. The Bohr magneton (muB), which has the value of the classical magnetic moment (mu) of the electron, can theoretically be calculated as muB = mu0 = eh/2mc = 9.2742 x 10 to the -2 erg/G = 9.2741 x 10 to the power -24 J/T, where ‘e’ and ‘m’ are the electronic charge and mass, respectively. ‘h’ is Planck’s constant divided by 2pi, and ‘c’ is the velocity of light.
Magneto-optical – It refers to the use of materials and effects where light’s properties are altered by an external magnetic field for practical applications. This involves the interaction between light and magnetic fields, leading to phenomena like Faraday rotation, where the polarization of light rotates as it passes through a material in a magnetic field. This effect is utilized in various technologies, including optical isolators, magnetic field sensors, and data storage.
Magneto-statics – It is the study of stationary magnetic fields.
Magneto-striction – It is the changes in dimensions of a body resulting from application of a magnetic field.
Magneto-strictive cavitation test device – It is a vibratory cavitation test device driven by a magneto-strictive transducer.
Magnetron – It is a high-power vacuum tube which acts as a self-excited microwave oscillator. It converts direct current electrical energy into high-frequency electro-magnetic waves by using a strong magnetic field which is perpendicular to the electric field, causing electrons to spiral in a way which generates micro-waves. These waves are then used in applications like radar systems and micro-wave ovens.
Magnetron sputtering – It is a deposition technology involving a gaseous plasma which is generated and confined to a space containing the material to be deposited i.e., the ‘target’. The surface of the target is eroded by high-energy ions within the plasma, and the liberated atoms travel through the vacuum environment and deposit onto a substrate to form a thin film.
Magnet steels – These are normally alloy electrical steels. The outstanding property of these steels is their ability to retain magnetism. Cobalt, chromium, and tungsten are the alloying elements normally used to improve this characteristic.
Magnet wire – It is the class of wire manufactured for winding electromagnetic coils such as in motors or transformers.
Magnification – It is the ratio of the length of a line in the image plane, e.g., ground glass or photographic plate, to the length of the same line in the object. Magnifications are normally expressed in linear terms and in units called diameters.
Magnifying transmitter – It is a concept for a signal transmitter which uses a resonant transformer to provide a high voltage.
Magnitude – It is the property of relative size or extent, whether large or small.
Magnus effect – It is the phenomenon where a spinning object’s path is deflected in a fluid (like air or water) because of a pressure difference created by its rotation. The side of the object moving in the same direction as the fluid flow has a lower pressure, while the side moving against the flow has a higher pressure. This pressure difference results in a sideways force that curves the object’s trajectory.
Main air supply – It is the primary system which delivers air to a space or device, frequently involving the production and distribution of compressed air through a network of pipes or ducts. The system’s components are designed to provide the needed flow rate, pressure, and quality of air for the intended function, such as powering pneumatic equipment, ventilating a room, or providing breathable air in protective suits.
Main bearing – It is a bearing supporting the main power-transmitting shaft.
Main distribution frame – In a telephone central office, It is the equipment which connects to subscriber circuits.
Main drive – It is the primary power source responsible for propelling the conveyor system. Routine inspections are crucial to maintaining optimal functionality, alignment, and overall performance.
Main duct – It is a central, primary channel which carries fluid or air through a system. In HVAC (heating, ventilation, and air conditioning) systems, it is the largest, central duct which branches off to supply air to smaller ducts throughout a building.
Main electric grid – It is an interconnected network which delivers electricity from producers to consumers through a system of power plants, transmission lines, substations, and distribution lines. It manages the flow of power by balancing supply and demand, and it allows for the integration of several energy sources, ensuring a reliable and economical supply of electricity across a wide area.
Main feeder – It is a main electrical conductor which distributes power from a substation to a broader area, from which subsequent branches or ‘distributors’ are tapped off to supply individual consumers. The main feeder is designed for high current capacity and has a constant current along its length since no loads are taken from it.
Main-frame computer – It is a large centralized computer system which is used for large volumes of data or supporting multiple interactive terminals, with large input / output capacity, normally expected to provide critical services to an organization with a predictable degree of reliability.
Mains electricity – It is the commercial electric power, purchased from an off-site source shared by several consumers. Regional supplies vary in voltage, frequency, and technical standards.
Main girder – It is a large, horizontal, primary structural beam which supports heavy loads by transferring weight to vertical supports like columns. It is an important component in large structures such as bridges and buildings, built to handle higher loads and longer spans than smaller beams. Girders are normally made of steel or reinforced concrete and frequently have an ‘I’ shape for strength.
Mains hum – It is the interference on an audio or visual signal related to the power line frequency.
Main load-carrying component – It is a structural part of a building or machine which bears and transfers the main weight or forces to the foundation or another support. These components form the fundamental skeletal framework of a structure, ensuring its stability and integrity by supporting the load of the building itself, its contents, and external forces. Examples include load-bearing walls, beams, and columns.
Main pipe rack – It is a structural framework, frequently a large steel or concrete elevated structure, which supports and routes process and utility pipes, instrument and electrical cable trays, and sometimes mechanical equipment through a plant. It acts as a central ‘artery’ for the plant, transferring fluids and other materials between different units, equipment, and storage or utility areas.
Main process variables – These are the key parameters in upstream production facilities, including pressure, liquid level, temperature, and flow, which fluctuate within specified limits to facilitate fluid movement and achieve necessary separation for sales or disposal.
Main span – Main span of a bridge is the principal section, defined as the distance between the centres of adjacent main supports (like towers or piers). This is the longest span in a bridge and does not refer to the total length of the structure, but rather the distance of the largest single unsupported section.
Main-spring – it is a spiral ribbon shaped spring used as a power source in watches, clocks, and mechanically powered flash lights.
Mainstream velocity – It is the speed of a fluid flow normally measured in length per unit of time like meters per second. It is a key parameter in fluid dynamics, representing the speed of the main flow in a system before it interacts with other elements like a wall or a secondary jet. In a more general sense, ‘mainstream’ can refer to the main, dominant flow in any given system.
Maintainability – In reliability theory, it means the measure of an item to be retained in, or restored to, a specified condition when maintenance is performed by personnel having specified skill levels and using prescribed procedures and resources, at each prescribed level of maintenance and repair.
Maintenance – It refers to supervising and preserving equipment and facilities used in industrial or manufacturing settings. It consists of servicing and repair of the equipment and facilities. It is the application of best practices to increase equipment up time of equipment and facilities. It includes scheduled and unscheduled maintenance. Maintenance can be scheduled as per the age of equipment or usage of equipment. Unscheduled maintenance can occur after equipment failure.
Maintenance activity – It consists of taking the decisions and actions regarding the upkeep of the plant, equipment, and facility. These are inclusive, but not limited to (i) actions focused on maintaining and analyzing the data related to the health of the plant, equipment, and facility, (ii) planning of adequate and necessary inventory of spare parts, lubricants, fast moving consumables, and storage items including standardization of spares and consumables, (iii) actions focused on scheduling, procedures, work / system control and optimization, and (iv) performance of routine, preventive, predictive, scheduled, and unscheduled actions aimed at preventing equipment failure as well as achieving the goal of increasing efficiency, reliability and safety. Further, besides the rectification of the faults in the equipment, the maintenance activities include (i) up-gradation of the existing plants and equipments and training maintenance personnel to attain the required technical skills, (ii) effective maintenance of the old equipment for higher availability, (iii) cost optimization of all maintenance functions, (iv) improvement of maintenance activities in the areas of tribology and terotechnology, (v) reconditioning of used / unserviceable spare parts, (vi) development of indigenous sources for parts for import substitution, (vii) setting up of an effective maintenance information management systems (MIMS), (viii) effective utilization of the maintenance personnel, and (ix) carrying out in-house research and development activities for effecting improvements in maintenance practices.
Maintenance costs – It refer to the expenses incurred to keep assets, equipment, facilities, or infrastructure in good working order, including regular upkeep, repairs, and replacements.
Maintenance engineering – It is the discipline of applying engineering principles to ensure that equipment, systems, and facilities operate reliably, safely, and cost-effectively. Professionals in this field develop and execute maintenance strategies, such as preventive and predictive maintenance, to minimize downtime, reduce costs, and maximize productivity throughout the life cycle of assets. This can include everything from installing and maintaining heavy machinery to trouble-shooting complex systems in different industries.
Maintenance information management systems (MIMS) – It refers to a type of software which organizations use to manage the maintenance activities in the organization. It includes day-to-day maintenance scheduling, planned maintenance and other maintenance practices, maintenance of equipment history, and inventory control for spare parts etc.
Maintenance log book – It is a comprehensive record which meticulously documents all maintenance activities, inspections, and repairs performed on the conveyor system. It serves as a historical record for system health and adherence to maintenance schedules.
Maintenance personnel – They refers to the people responsible for keeping a physical plant or equipment in good working order. This includes performing repairs, routine maintenance, and addressing any issues which arise to ensure smooth operations. Essentially, they are the individuals who ensure that buildings, machinery, and other infrastructure are well-maintained and functioning properly.
Maintenance philosophy – It is a high-level strategy and set of guiding principles for managing the upkeep of assets to ensure their functionality, longevity, and value. It serves as a framework which dictates how maintenance is organized and executed, including the types of maintenance strategies used (like proactive or reactive), resource allocation, work processes, and how to prioritize maintenance efforts. It aims to balance costs, safety, and performance to meet organizational objectives.
Maintenance planning – It is the process of determining what maintenance work needs to be done, why, and how it is to be completed, including identifying necessary resources like parts, materials, and labour. It is different from maintenance scheduling, which focuses on the when and who for performing the tasks to maximize asset uptime and minimize costs.
Maintenance practices – There are several types of maintenance practices which are being followed. These include planned maintenance, routine or reactive maintenance, preventive maintenance, predictive maintenance and reliability centered maintenance.
Maintenance procedure – It is a detailed, step-by-step guide for performing a specific maintenance task on equipment or a system. It standardizes maintenance to ensure consistency, safety, and efficiency, and includes instructions on everything from needed tools and safety precautions to the actual execution of the task. These procedures are important for complex or repetitive tasks, training, and maintaining compliance with safety and regulatory standards.
Maintenance, repair and operations (MRO) inventory – It refers to supplies, spare parts and other materials needed for routine maintenance, repair and operations. This inventory is critical for the smooth running of the organization. However, unlike raw materials, this inventory does not become a part of finished goods offered to customers. Spare parts, office supplies, lubricants, repair tools, personal protective equipment and safety equipment are some examples of maintenance, repair and operations inventory.
Maintenance record – It is a documented history of all maintenance activities performed on an asset, such as an inspection, repair, or replacement. These records include details like the date of service, the type of work done, parts used, and the technician’s notes, providing a comprehensive log to track an asset’s history, ensure compliance, and aid in future management decisions.
Maintenance requirement – It is a task, standard, or financial obligation which is to be fulfilled to keep something in a functional, safe, or compliant state.
Maintenance schedule – It identifies the requirements and periodicities for regular and systematic examination, inspection, maintenance, and testing of all plant so that the plant operates normally, reliably, and safely.
Maintenance scheduling – It is a predefined plan outlining regular tasks and intervals for inspecting, servicing, and repairing conveyor components. It ensures proactive upkeep and prolonged system reliability.
Maintenance strategy – It is a structured approach to asset upkeep which outlines the plan and procedures for maintaining equipment, facilities, and assets to ensure optimal performance, reliability, and safety. It is a comprehensive blueprint for minimizing downtime and costs by combining different maintenance types, such as preventive, predictive, and corrective maintenance. The goal is to balance efficiency and resource allocation to extend equipment lifespan and achieve operational goals.
Maintenance task – It is a specific activity to keep an asset, equipment, or system in good working order through actions like inspection, cleaning, lubrication, repair, or replacement. Tasks can be scheduled in advance (preventive) or performed in response to a failure (corrective) to ensure optimal performance, prevent breakdowns, and extend the life of the asset.
Main transformer – It is a large power transformer in a substation which increases the voltage from a power generator for long-distance transmission, or steps it down to a usable level for distribution. It is a critical component which transfers electrical energy between circuits of different voltage levels using electro-magnetic induction. These transformers are vital for the efficient and stable supply of electricity to consumers.
Major accident hazard – It is a potential source of danger in an industrial or other setting which can lead to a major incident, such as a large emission, fire, or explosion. These events have the potential to cause serious harm to people, damage property and the environment, and are frequently associated with the handling of hazardous substances in industrial processes. Identifying and mitigating these hazards through risk assessments and safety measures is important for prevention.
Major axis – It is the axis of a structural element with the largest dimension, or the principal axis about which the moment of inertia is highest, making it the ‘strong axis’ for resisting bending. For a rectangular cross-section, it is the longer of the two axes passing through the centroid, while the minor axis is the shorter, ‘weak axis’. Understanding the major axis is important for design since aligning it with the main load direction maximizes the structure’s strength and stability.
Major category – It refers to a broad classification of a specialized field, such as the five main branches: civil, mechanical, electrical, metallurgical, chemical, and industrial engineering. These categories are distinct groupings which encompass a wide range of sub-disciplines and applications for designing, building, and improving technological solutions.
Major component – It refers to an essential, high-level part of a larger system, machine, or structure which is critical to its overall function or integrity. The specific definition varies by field, but common examples include the engine or transmission of a vehicle, and the rotor or gearbox of a wind turbine. These components are typically more substantial than minor parts and frequently represent a substantial portion of the item’s cost, complexity, or performance.
Major diameter – It is the largest diameter of a screw thread, measured across the crests of an external thread. It is the nominal diameter of the screw and is the critical dimension which determines the overall size of the fastener.
Major injuries – This term is no more used internationally. The definition of the term varies widely from organization to organization. For example, length of absence can range from 45 days to 90 days, (ii) hospitalization, and (iii) medical definition either by own medical staff or by legislation.
Major mineral – It is a mineral which constitutes a substantial percentage, typically ranging from 70 % to over 90 %, of a specific ore deposit, such as celestite (SrSO4) in sedimentary deposits associated with rock salt and gypsum.
Major principal stress – It is the maximum normal stress acting on a point within a material, and it occurs on a plane where there is no shear stress. This is one of two principal stresses (the other being the minor principal stress), which represent the extreme values of normal stress at that point.
Major revision – It signifies a substantial change to a design, impacting its form, fit, or function (FFF), which typically needs a substantial redesign and can necessitate re-approval. These changes are frequently indicated by a change in the version number to the left of the decimal point (e.g., 2.0 to 3.0) and differ from minor revisions, which are normally limited to less important updates like documentation or spelling corrections.
Major strain – It refers to the highest deformation measured in the direction of an object’s longest axis after it has been deformed, calculated as the change in length of the major axis of the deformed ellipse divided by its original diameter. It is a specific type of strain which occurs when a material’s shape changes under stress, frequently discussed in contexts like the thermoforming of materials where an object is stretched into an elliptical shape.
Make-up gas – It refers to gas added to a gas-condensate reservoir to maintain pressure or, more commonly, to a supplemental gas in gas chromatography (GC) used to improve detector sensitivity. In gas chromatography, make-up gas is an inert gas like nitrogen or helium which is added to the flow between the column and the detector to minimize band broadening and optimize the flow rate for the detector.
Make-up water – Make up water is frequently needed in systems which use recirculating water. It is that water which is added to the system to compensate for the water (i) lost in the process, (ii) lost by the evaporation, and (iii) lost due to the leakages. In boiler, it is the water which is added to boiler feed to compensate for that lost through exhaust, blowdown, and leakage etc.
Male fasteners – These fasteners have threads on the outside of their body, allowing them to screw into or be inserted into a corresponding female component. Common examples of male fasteners include bolts, screws, and studs. The most common types of male fasteners used in industry are, slotted head, flat (or countersunk) head, round head, socket (or ‘allen’) head, button head and socket set screw. Male fasteners are designed to mate with female fasteners, creating a secure joint.
Male slip fit – In these pipe fittings there are no threads. They slip fit into a slightly larger diameter sleeve.
Male threaded – These pipe fittings have exterior threads. They are screwed into the inside of pipe end of a larger diameter with internal threading.
Malleability – It is the characteristic of metals which permits plastic deformation in compression without fracture.
Malleableization – It is the annealing or heat-treating operation performed on white iron castings to transform the combined carbon into temper carbon.
Malleabilizing – It consist of annealing white iron in such a way that some or all of the combined carbon is transformed into graphite or, in some cases, so that part of the carbon is removed completely.
Malleable iron – It is a cast iron made by prolonged annealing of white iron in which decarburization, graphitization, or both take place to eliminate some or all of the cementite. The graphite is in the form of temper carbon. If decarburization is the predominant reaction, the product shows a light fracture surface, hence whiteheart malleable. Otherwise, the fracture surface is dark, hence blackheart malleable. Ferritic malleable has a predominantly ferritic matrix, while pearlitic malleable can contain pearlite, spheroidite, or tempered martensite, depending on heat treatment and desired hardness.
Malleable cast iron – It is cast as white cast iron, then ‘malleablized’ (i.e., heat treated to impart ductility to an otherwise brittle material). The micro structure consists of ferrite and particles of free graphite. This cast iron encompasses a form of graphite called temper carbon. This form of graphite is produced by the heat treatment of white cast iron. When a white cast iron is heated for an extended period of time (about 60 hours) at a temperature of 960 deg C, the cementite decomposes into austenite and graphite. By slow cooling from 960 deg C, the austenite transforms into ferrite or pearlite depending on the cooling rate and the diffusion rate of carbon. The ductility and toughness of malleable cast iron falls between that of ductile cast iron and gray cast iron. Now a days malleable cast irons have been replaced by the more economically produced ductile irons cast for many uses. Malleable cast irons besides ductility have good machinability. Ferritic malleable cast irons are more ductile and less strong and hard, than pearlitic malleable cast irons. Applications of malleable cast irons include parts of power train of vehicles, bearing caps, steering gear housings, agricultural equipment, and railroad equipment.
Mallet – It is a tool used for imparting force on another object, frequently made of rubber or sometimes wood, which is smaller than a maul or beetle (tool), and normally has a relatively large head.
Manageability – It is the quality of being easily controlled, understood, and maintained. It encompasses the ability to control a system through self-control or external techniques, and in a broader sense, refers to the skills needed to manage engineering projects, teams, budgets, and technical activities efficiently and effectively.
Management – It is a process which refers to a number of activities and functions. Management as an art refers to implementation, and management as a science refers to a systematic and scientific knowledge. As per these perspectives, different meanings are attributed to the concept of management. However, in its most general definition, management can be seen as a process directed to manage individuals and groups for a specific purpose. In other words, management is to ensure that the organization resources reach the goals by planning. Management can also be defined as the process of working with people and resources for the realization of organizational goals, for the coordination of the work with others or through others, efficiently, and effectively.
Management control – It an approach which enables the organization to produce desired results (normally expressed in terms of performance) by taking actions to achieve those results and by dealing with the dangers brought in by external difficulties (particularly those related to the market, competitors and the economic or political environment) and the internal difficulties of the organization. It consists of a systematic effort on the part of the organizational management. It is required to assure that all organizational resources are being used in the most effective and efficient manner possible in order to achieve the organizational objectives and goals. It constitutes (i) setting of performance standards with planning objectives, (ii) design of information feedback systems, (iii) comparison of actual performance with the predetermined standards, plans or objectives in order to determine whether there are any deviations and to measure their significance, and (iv) taking of any remedial action if needed.
Management functions – These are the core activities which managers perform to achieve organizational goals, which are normally defined as planning, organizing, staffing, leading (or directing), and controlling. These functions involve setting goals and strategies, assigning tasks and resources, recruiting and motivating employees, and monitoring performance to ensure goals are met efficiently and effectively.
Management information system (MIS) – It is a planned system for collecting, storing, and disseminating data in the form of information needed for carrying out different functions of the management. It provides information which the organization needs to manage itself efficiently and effectively. It deals with information related to technologies, processes, operation, human resource, commercial activities, and such other things within the organization and in its environment. Information means data which have been shaped into a form which is meaningful and useful to its users in the organization. Data, in contrast, are streams of raw facts representing organizational activities before they have been organized and arranged into a form which the management and other organizational users can understand and use. Management information system is a systematic organization and presentation of information which is normally needed by the organizational management for taking better decisions. It is an information system which integrates data from all the departments it serves and provides the management and the users with the information they need it is distinct from other information systems in that it is used to analyze and facilitate strategic and operational activities.
Management level – It refers to the hierarchical structure within an organization which defines a manager’s authority, responsibilities, and role. The three main levels are top, middle, and lower, each with a different focus such as top management sets strategy, middle management implements plans, and lower management oversees day-to-day operations.
Management network – It is a dedicated, isolated network infrastructure for overseeing and controlling the main network devices of the organization. Its purpose is to ensure centralized control, improve security by separating administrative traffic, and enable efficient monitoring and trouble-shooting of the main network. This separation helps maintain optimal performance, security, and scalability for the overall network infrastructure.
Management process – It is a series of interconnected functions which include planning, organizing, staffing, leading, and controlling to achieve an organization’s goals. It involves setting objectives, creating a plan to meet them, and then guiding and monitoring the execution of that plan to ensure efficient use of resources and successful completion.
Management representative – It is a professional who acts as a supervisor on behalf of senior management, frequently focusing on areas like quality management systems. Their duties include communicating expectations, assigning tasks, and reporting employee performance to senior managers, and they serve as a liaison between upper management and employees. In a quality management context, they ensure compliance with standards, facilitate audits, and maintain the effectiveness of the system.
Management review – It is a formal, systematic process where top management assesses the effectiveness, adequacy, and suitability of an organization’s management systems. The goal is to ensure the systems are performing as intended, align with organizational goals, and identify opportunities for improvement. This process is a key component of continuous improvement, frequently mandated by standards like ISO 9001, and involves analyzing performance data to make informed decisions and drive necessary changes.
Management styles – Management styles constitute a broad concept which includes elements such as organization, planning, directing, coordination, control, procurement and selection, and authority sharing. The most important elements which bring the organization to success are the management style and the people. Management style expresses the way the managers use their authority over the employees and level of relationship with the employees in reaching the goals of the organization. Managers display one or more of the management styles. Some of the most commonly followed management styles are (i) authoritarian style which is also referred to as coercive style of management, (ii) authoritative style which is full of authority and influence, (iii) democratic style in which managers seek to achieve their objectives by consensus and employee participation, (iv) affiliative style which is closely related to the democratic style., (v) permissive style which is also referred to as Laissez-Faire style and in which the managers give little or no direction to the employees, (vi) indifferent style which is a bit similar to the permissive style, and in which managers just cannot be bothered, (vii) coaching style in which managers focus on training, guiding, counselling, and employee personal development for the future growth of the organization, (viii) pace-setting style in which managers set examples and standards for high performance, (ix ) visionary style in which managers move their employees to share positive dreams of the potential benefits and opportunities which they stand to gain, (x) bureaucratic style which is dominated by the procedure resulting the managers completely inflexible, (xi) defensive style which is practiced by managers who always seek to find fault from the employees and give the impression that they are correcting the fault, (xii) repulsive style which is characterized by the tendency of the manager to refuse being promoted to managerial positions and which extravagantly relies on the subordinates’ independence.
Management techniques – A large number of techniques are available to the management for the solving of the organizational issues. Selection of the proper techniques and then successful use of the selected techniques help the management to make the right decisions that leads to the effective and the efficient working of the organization. Right decisions taken at appropriate time not only enhances the processes, products and services of the organization but also propels the organization to deliver superior performance and profits. Successful use of such techniques requires an understanding of the strengths and weaknesses of each technique, as well as an ability to creatively integrate the right techniques, in the right way, at the right time. The secret is not in discovering one simple solution, but in learning which techniques to use, and how and when to use them.
Management techniques for entire organization – There are several management techniques which are not specific to one area of the organization. These techniques are rapidly becoming recognized as important keys for the organizational success. They normally cover several areas of the organization and some of them are very important management techniques. Management techniques which available for use of the entire organization are (i) vision and mission statements, (ii) bench marking, (iii) digitization process, (iv) core competencies, (v) complexity reduction, (vi) change management, (vii) contingencies planning, (viii) business process reengineering (BPE), (ix) management information system (MIS), (x) time management, (xi) continuous improvement process, (xii) crisis management, (xiii) creation of sustainable future, (xiv) decision making process, (xv) building organizational capabilities, (xvi) policy and strategy management, (xvii) creating problem solving culture, (xviii) harnessing of creativity and innovations, and (xix) disruptive innovation laboratories etc.
Management techniques for financial management – The main function of the financial management is to manage the finances of the organization. The functions include amongst others management of financial resources, management of receivables and expenditures and keeping proper accounts, management of cash flow, making timely payments, arrangement of finances for capital expenditure with minimum costs to the organization, and parking of savings for maximum yields etc. The management techniques available for the financial management include (i) budgeting, (ii) cost management (iii) auditing, (iv) risk analysis and management, (v) data analysis and management, (vi) contingency planning, (vii) resource management, and (viii) investors relation management etc.
Management techniques for human resource management – The main function of human resource management is to manage the personnel of the organization. The functions of the human resource management include amongst others human resource planning, recruitment of the employees, bringing the recruited employees on board, the talent enhancement of employees, deciding of the compensation, employees appraisals, handling of employees discipline, motivation of the employees, recognition and rewards, industrial relations, succession management, career planning, and welfare of employees etc. The management techniques available for the human resource management include (i) balanced scorecard, (ii) conflict management, (iii) delegation of power, (iv) compensation management, (v) employees’ engagement, (vi) employees’ satisfaction and satisfaction survey, (vii) development and implementation of effective communication system, (viii) industrial relation management, (ix) inter personal relationship, (x) maintenance of organizational discipline, (xi) planning for organizational learning, (xii) developing employees’ competencies, (xiii) tracking employees’ motivation (xiv) process approach to personnel management, (xv) talent management, (xvi) team working, (xvii) talent acquisition, (xviii) succession planning, (xix) outsourcing, (xx) employees’ loyalty management, and (xxi) people strategy for excellence etc.
Management techniques for managing organization future – Adoption to change and managing the future of the organization is important not only for the success of the organization but also for its survival. Management of the organization future is needed for meeting the organizational vision. It is needed either because of the external pressures or because of the internal reasons. It is needed either for consolidation or for expansion. It is also required for the enhancement of the organizational capabilities. Planning function of the management is deeply rooted in the management of the organization future. The management techniques used for the future planning of the organization includes (i) feasibility studies, (ii) creation of sustainable future, (iii) forward and backward integration, (iv) diversification strategies, (v) management of uncertainties, (vi) mergers and acquisitions, (vii) project evaluation and review technique, (viii) SWOT analysis, (ix) resource management and (x) risk management etc.
Management techniques for the management of safety, security and welfare – The health, safety and protection of employees, equipment and the environment are of serious concern in an organization. The health and safety of employees is crucial since it affects both economic and social factors. The organization also requires careful attention to security and safeguards. Security is aimed at preventing intentional acts that might harm the organization or result in the theft of materials. Employees’ welfare refers to those measures of the organization which aim at promoting the physical, psychological, and general wellbeing of the employees. The basic aim of welfare measures is to improve the living and working conditions of the employees along with their families. The management techniques available for the safety security and welfare in the organization are (i) development of occupational health and safety management system, (ii) safety audits, (iii) safety inspections, (iv) safe working procedures and work practices, (v) safety awareness and training, (vi) hazard, hazid, hazan, and hazop studies and analyses, (vii) risk management, (vii) safety consciousness, (vii) safety promotions, (viii) accidents / incident investigations and analyses, (ix) safety measurement and monitoring, (x) emergency preparedness, (xi) compliance to safety rules and regulations, (xii) use of personal protective equipments (PPEs), (xiii) stress and fatigue management at work place, (xiv) preventive security measures, (xv) protective security measures, (xvi) detective security measures, (xvii) punitive security measures, (xviii) security audits, (xix) use of security gadgets, (xx) intramural welfare facilities, and (xxi) extramural welfare facilities etc.
Management techniques for operational management – Functions of the operations in the organization are to manage various processes of the organization which produces products and services for the customers. These functions include production planning and control, operation of plant and equipment, maintenance and upkeep of the plant and equipment, optimization in the use of raw materials, conservation of materials and energy, maintenance of environment, and management of technological and workplace discipline etc. The management techniques for the operational management include (i) working with systems and procedures, (ii) development and implementation of management systems such as quality management system, environment management system, and energy management system, (iii) quality circles, (iv) value engineering, (v) suggestion scheme, (vi) quality assurance, (vii) process and quality control, (viii) management information system, (ix) knowledge management, (x) inventory management and control, (xi) data based decision making, (xii) adherence to technological discipline, (xiii) annual budgeting, (xiv) cost control, (xv) total quality management, (xvi) statistical quality control, (xvii) six sigma, (xviii) maintenance management system, (xix) process management, (xx) process automation, (xxi) performance management, (xxii) environmental, energy and technological audits, (xxiii) analytical thinking, (xxiv) failure analysis, (xxv) disaster management and contingency planning, and (xxvi) adoption of standardization techniques etc.
Management techniques for organizational functions involving external agencies – There are a number of organizational functions where the employees are to interact with outside agencies. Further the organization is to build and sustain its corporate image. Managing of the corporate image is the key to security and success of the organization and helps it in maintaining public trust. Major of the functions where the organizational employees come in contact with external agencies include sales and purchase functions, dealing with regulatory authorities and government, societal functions where the organization comes in touch with society, media and local authorities, and investors relations. Collectively the outside agencies are termed as stakeholders. Depending on the specific organization, stakeholders may include governmental agencies, statutory bodies, social activist groups, self-regulatory organizations, employees, shareholders, customers, suppliers, distributors, media and even the community in which the organization is located among many others. Management techniques available for organizational functions involving external agencies are (i) customer loyalty, (ii) customer segmentation, (iii) customer relationship management, (iv) customer focus, (v) customer satisfaction, (vi) customer centric approach, (vii) customer satisfaction survey, (viii) building of corporate image, (ix) branding, brand and brand management, (x) price optimization process, (xi) corporate social responsibilities, (xii) external communication, (xiii) supply chain management, (xiv) strategic alliances, (xv) involving stakeholders in the decision making processes, (xvi) development of purchase and sales procedures, (xvii) contract management, (xviii) developing negotiating skills, (xix) building of confidentiality and transparency, and (xx) investors relationship management etc.
Manager – A manager is an individual responsible for controlling and organizing a n operation or department, overseeing a team of employees to achieve the organizational goals. Managers are a link between upper management and employees, and their roles include planning, decision-making, and ensuring the productivity and efficiency of the group and its resources.
Managerial ability – It is the set of skills and competencies needed to effectively lead, organize, and direct an organization to achieve its goals. It includes the capacity to make decisions, motivate employees, manage resources, and ensure the team or the organization functions efficiently and productively. Key managerial skills include planning, communication, decision-making, and leadership, which are frequently categorized into technical, human, and conceptual skills.
Managerial control process – It is a process which is broadly defined as an operation that uses resources to transform inputs into outputs. It is the resource which provides the needed energy to the process for the transformation to occur. In an organization there are two types of processes. The first type of processes is those processes which create, produce, and deliver products and services while the second type of processes are those processes which do not produce outputs bur are still necessary in the functioning of the organization. The first group of the processes can be called work processes while the second type of the processes can be called administrative processes. Both the types of the processes are important for the functioning of the organization and need adequate process control activities for their successful implementation.
Mandate – It is the authority or official command given to an organization or its members to perform a specific task or function. This can be a formal, legally binding document or an informal understanding, and it defines the organization’s purpose, goals, and boundaries. An organizational mandate can also refer to the specific duties assigned to a project or a role within the organization.
Mandrel – It is a blunt-ended tool or rod used to retain the cavity in a hollow metal product during working. It is a metal bar around which other metal may be cast, bent, formed, or shaped. It is also a shaft or bar for holding work to be machined. It is also a form, such as a mould or matrix which is used as a cathode in electroforming. In piling, mandrel is a full-length steel core set inside a thin-shell casing. It increases the structural capacity of the casing so that it can be driven. It helps in maintaining pile alignment and prevents the casing from collapsing. It is removed after driving is completed and prior to placing reinforced concrete. In case of composites, it is the core tool around which resin-impregnated paper, fabric, or fiber is wound to form pipes, tubes, or structural shell shapes.
Mandrel forging – It is the process of rolling or forging a hollow blank over a mandrel to produce a weldless, seamless ring or tube.
Mandrel lubricants – These are also known as mandrel release agents. These are specialized coatings or fluids applied to mandrels during the manufacturing process of hoses or other molded products. They facilitate the easy removal of the finished product from the mandrel after curing or molding by reducing friction and preventing adhesion between the material and the mandrel.
Mandrel radius – It is the distance from the centre of a bending mandrel to its outer surface, defining the tightness of the bend in a tube or pipe. It is also known as the centre-line radius (CLR) of the bend, which determines how sharply a tube is bent. This radius is critical in the bending process to ensure the tube maintains its shape and wall integrity.
Manganese – It is a chemical element. It has symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, frequently found in minerals in combination with iron. It is a transition metal with a multifaceted array of industrial alloy uses. It improves strength, workability, and resistance to wear. Manganese fulfils a variety of functions in steel. It is used as a deoxidizing agent in nearly all steels. It forms manganese sulphide inclusions which are spherical in the cast product. In the absence of manganese, sulphur inter-dendritic films of iron sulphide causing brittleness at hot working temperature (hot shortness). It effectively increases hardenability and up to 1.5 % and hence it is added for this purpose. In larger amounts, it is used to stabilize austenite, as in 14 % manganese steel. Manganese is normally present in all steel and functions as a deoxidizer. It also imparts strength and has responsiveness to heat treatment. It is normally present in quantities of 0.5 % to 2 %. In the range 0.3 % to 1.5 %, it is always present in steels to reduce the negative effects of impurities carried out forward from the production process e.g. sulphur embrittlement. It promotes the formation of stable carbides in quenched-hardened steels. Alloy steels containing manganese are pearlitic. Up to 1 %, it acts as hardening agent and from 1 % to 2 % improves strength and toughness. Alloy steels containing more than 5 % are non-magnetic. Alloy steels containing large proportions of up to 12.5 % manganese have the property that they spontaneously form hard skins when subject to abrasion (self-hardening properties). All commercial steels contain 0.3 % to 0.8 % manganese, to reduce oxides and to counteract the harmful influence of iron sulphide.
Manganese briquettes – These are compacted forms of manganese metal powder or ore used in different industrial applications, most notably in steelmaking. They serve as a convenient and efficient way to add manganese to molten metal for purposes like deoxidation, desulphurization, and alloying to improve the strength, hardness, and other properties of steel and high-manganese alloys. The briquetting process involves pressing manganese powder under high pressure, creating a stable, dense form which is easy to handle, transport, and store, while also preventing oxidation.
Manganese bronze – It is a high-strength bronze alloy mainly made of copper, zinc, and manganese, along with other elements like iron and aluminum. It is known for its excellent corrosion resistance, wear resistance, and strength, making it ideal for marine applications like propellers, as well as for high-stress components like gears, fasteners, and bearings.
Manganese austenitic steel – It is an alloy steel with a high percentage of manganese (typically 11 % to 14 %) which provides exceptional strength, durability, and wear resistance. It is also known as Hadfield steel. This material is known for its work-hardening properties, becoming harder and more impact-resistant with use, making it ideal for parts which experience intense wear and abrasion.
Manganese deposit – It is a concentration of manganese minerals found in geological formations, which can include sedimentary rocks and metamorphosed or volcanic environments. These deposits are significant because they are a major source of the manganese ore used to produce steel, batteries, and other alloys. The deposits form through different geological processes, with common types being chemical sedimentary, residual, and hydrothermal.
Manganese removal – It is the process of eliminating manganese from water, frequently through methods like oxidation and filtration. This is done to prevent issues like blackish-brown staining in fixtures, unpleasant odours, and deposits in pipes, which can occur when dissolved manganese oxidizes to an insoluble form. Different techniques are used, including chemical or biological oxidation, ion exchange, and precipitation.
Manganese steel – It is an alloy steel which contains a high percentage of manganese, typically 11 % to 14 %, which makes it exceptionally tough, durable, and wear-resistant. It is also known as Hadfield steel or mangalloy and becomes even harder and more resistant to wear when subjected to impact. Because of these properties, it is used in heavy-duty applications like railway components, dredging buckets, and rock crushers.
Manganese sulphide (MnS) – It is an inorganic compound composed of manganese and sulphur. It is known for its semiconductor properties and is used in several applications, including electronics and as a pigment in ceramics and glass. It can exist in different crystalline structures and has unique optical and magnetic properties, particularly at the nano-scale.
Manganese sulphide (MnS) inclusions – These are compounds of manganese and sulphur that which are normally found as non-metallic inclusions in steel. They can be deliberately introduced or naturally occur during steelmaking. While they can improve machinability, they can also negatively impact mechanical properties like fatigue and toughness if not properly controlled.
Manhattan distance – It is a way to measure the distance between two points in a grid-like space. It calculates the sum of the absolute differences of their Cartesian coordinates, effectively measuring the distance as if traveling along the grid lines.
Manhole – It is the opening in a pressure vessel of sufficient size to permit a man to enter.
Man-hours per ton (M-h/t) – It is a measure of labour efficiency of a steel plant. It is the ratio of total hours worked by steel plant employees to the tons shipped for a given period of time. Changes in the inventory level and work which is contracted out affects the reported measurement.
Manifold – It is system of pipes and valves for using a group of gas cylinders, or boil-off from vacuum insulated evaporators, to feed a single supply line. The advantages of the manifold system as compared with using a single cylinder are increased capacity and reliability, and also the possibility of a centralized supply for multiple users. The two main design aspects are use of a banks of cylinder connected in parallel and switch-over among different banks. By drawing from more than one cylinder simultaneously, a higher total quantity of gas is available, which means the system does not need to have the cylinders replaced very frequently. The number of cylinders connected at a time can be varied, and a large supply can be provided while still using reasonably small cylinders. It is also a pipe or header for collection of a fluid from, or the distribution of a fluid to a number of pipes or tubes.
Manipulated variable (MV) – It is the quantity in a process which is adjusted or otherwise manipulated in order to influence the PV. It is also used to describe the output signal generated by a controller; i.e. the signal commanding (manipulating) the final control element to influence the process.
Manipulators – They are used for rotating the rolled stock at a specific angle around its longitudinal axis.
Man-made (synthetic) diamond – It is a manufactured diamond, darker, blockier, and considered to be more friable than majority of the natural diamonds.
Man-made disaster – It is a catastrophic event caused by human action, negligence, or a failure in a man-made system. These are different from natural disasters and can stem from technical errors, poor management, intentional acts, or the widespread impact of technology. Examples include industrial accidents, transportation crashes, infrastructure collapses, and incidents involving hazardous materials, such as chemical spills or nuclear accidents.
Man-made fibres – These are fibres artificially produced by humans, unlike natural fibres like cotton or wool. They can be made from natural materials which have been chemically altered, such as rayon from wood pulp (regenerated cellulose), or from synthetic polymers derived from chemicals like petroleum, such as polyester, nylon, and acrylic.
Mannesmann inclusion detection by analysis surfboards (MIDAS) – Steel samples are first rolled to remove porosity and then ultrasonically scanned to detect solid inclusions and compound solid inclusions / gas pores. This method has been recently rediscovered as the ‘liquid sampling hot rolling (LSHP) method.
Mannesmann process – It is a process for piercing tube billets in making seamless tubing. The billet is rotated between two heavy rolls mounted at an angle and is forced over a fixed mandrel.
Mansion-Coffin relationship – It is also known as the Coffin-Manson equation or law. It is an empirical relationship which describes the behaviour of materials under low-cycle fatigue. It links the plastic strain amplitude with the number of cycles to failure.
Mantle – It is the soil or other unconsolidated rock material normally referred to as overburden. It is a sheath of manganese steel which fits over the iron or steel cone of the breaking (gyrating) head of a gyratory crusher. It is also that part of a blast furnace which carries the weight of the stack, continuing up from the bosh. It is the outer wall and casing of a free-standing blast furnace above the hearth. Mantle is also the outer zone in a zoned crystal (an overgrowth). It is also the zone of the earth below the crust and above the core, which is divided into the upper mantle and the lower mantle, with a transition zone between.
Mantle tank – It is a double-walled storage tank used for heat exchange, where a heat transfer fluid circulates in the space between the inner and outer walls to heat the contents of the inner tank. This design, also known as a jacket or annular heat exchanger, is normally used in solar thermal systems to transfer heat from a solar collector to the water inside the tank, improving heat transfer area and sometimes improving thermal stratification.
Manual activation switch – It is a simple one-direction switch which is used to manually turn the conveyor on and off, providing straightforward control over system operation.
Manual actuators – These actuators are normally used for overrides of power actuators described above. This is an important safety measure in case the power actuator fails. Manual actuators typically consist of either a lever or a wheel (used for larger valves) connected to a screw or thread which turns the valve.
Manual and automatic instruments – Manual instrument needs the services of an operator, where as in automatic instruments there is no need for an operator. As an example, measurement of rotational speed by a hand operated tachometer an operator is needed to make the contact of the instrument with the rotating shaft. For measurement of temperature by a resistance thermometer by wheat-stone bridge in its circuit an operator is required to indicate the temperature being measured. On the other hand, in measurement of temperature by mercury-in-glass thermometer, no operator is needed.
Manual cooling bed – It has slope for the bar to move forward by sliding action due to gravity. Mechanical cooling beds are rake-type. Several types of mechanical cooling beds are used. The rolled bar as it enters the cooling bed slides onto the first notch on the rakes. The initial notches provide continuous support for the bar on a casting called a grid casting. Long plates with notches set at some distance apart, support the bar after it moves beyond the grid castings. The bar moves across the cooling bed by the movement of alternative plates moving in a cycle of lift, move, and retract, by the action of eccentric cams. Repeating of this cycle moves the bars as they are delivered from the mill. The length of the cooling bed is determined by the maximum run-out bar length, optimized by the selling lengths to minimize crop losses. The width of a cooling bed is determined on the basis of mill productivity (tons/hour) and the time required for cooling.
Manual gas shut-off valve – It is a manually operated valve in a gas line for the purpose of completely turning on or shutting off the gas supply.
Manual gear operator (MGO) – It is the gear operator which is operated manually with a hand-wheel.
Manual hoist – A hand chain hoist is a type of manual hoist powered by a hand chain to lift or lower the load. It is a manual hoist which is a force multiplier. It gives a workman the ability to lift very large loads (up to 50 ton) with ease by using mechanical advantage. Most hand hoists are used for infrequent maintenance applications where speed is not a requirement. They are considerably less expensive than powered hoists, but they require physical effort (pulling of the hand chain) to lift the load. They are not fast and are not generally specified for continuous lifting applications, especially when long lifts are required. Manual hoists can be trolley mounted. Trolleys can be of several different configurations. The most common are the hand powered (plain or push type). Also, trolleys can be hand geared (hand chain driven) and motorized (electric or air powered).
Manual measurement – It is a hands-on process where a human operator directly uses tools or their own senses to take a measurement, as opposed to a machine doing it automatically. It involves using physical instruments like a ruler, calipers, or a feeler gauge, and needs an operator to read the instrument or interpret the results, such as reading a scale or determining the correct feel for a tight fit.
Manual metal arc welding (MMAW) process – It is also known as shielded metal arc welding (SMAW) process or flux shielded arc welding (FSAW) process. It is normally called stick, or covered electrode welding. It is a manual welding process whereby an arc is generated between a flux-covered consumable electrode and the work piece. The process uses the decomposition of the flux covering to generate a shielding gas and to provide fluxing elements to protect the molten weld-metal droplets and the weld pool. In the manual metal arc welding process, the arc is initiated by momentarily touching or ‘scratching’ the electrode on the base metal. The resulting arc melts both the base metal and the tip of the welding electrode forming a pool of molten metal (weld pool) which cools to form a joint. The molten electrode metal / flux is transferred across the arc (by arc forces) to the base-metal pool, where it becomes the weld deposit covered by the protective, less-dense slag from the electrode covering. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapours which serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination. The metal arc welding process is the most widely used welding process. It is the simplest, in terms of equipment requirements, but it is, perhaps, the most difficult in terms of welder training and skill-level requirements.
Manual mining method – It is normally limited to float ores. Mining of reef ore is also being done manually on a small scale. The float ore area is dug up manually with picks, crow bars, and spades, and then the material is manually screened to separate + 10 millimeters float ore which is then stacked up. The waste is thrown back into the pits. As regards to the reef ores, holes of 0.6 meters deep and 30 millimeters to 40 millimeters diameters are drilled with hand held jack-hammers operated with portable compressors. These holes are with a spacing of around 0.6 meters and each hole is charged with 150 grams to 200 grams of gun powder or gelatin cartridges. The blasted broken ore is manually screened, stacked for loading in dumpers for dispatch.
Manual mode – Manual mode is when the controller’s decision-making ability is by-passed to let a human operator directly determines the output signal sent to the final control element.
Manual motor controller – It is a manually operated electrical device for starting and stopping motors, and for providing overload, short-circuit, and phase failure protection. Manual motor controllers frequently combine a manual motor protector, contactor, and wiring connector into a single unit, offering a compact and efficient solution, especially for group installations or applications with limited space. Some manual motor controllers, marked as ‘suitable as a motor disconnect’, can also be used as a lockout point, but this is to be verified as it is not a universal feature.
Manual over-ride – It consists of a manual device fitted to an actuator for operating the valve when the normal motive power is not available.
Manual press – Different types of manual presses exist for the densification of the materials. Some come in the form of piston or screw presses but are operated with bare hands and hardly uses electricity. Manual press is designed for the purpose of briquette making or adapted from existing implements used for other purposes. Manual clay brick making press is a good example with which briquettes can be made from the feedstock. The manual press is made from both metal and wood with the latter being the most common. These machines operate with very minimal pressure. Binder addition to the feedstock is needed. Manual presses are characterized by low capital costs, low operating costs, and low levels of skill needed to operate the machine. However, it has a low production capacity of around 5 kilograms per hour to 50 kilograms per hour.
Manual process – It is a task or workflow which needs human effort to complete, rather than using automation or machines. This involves human intervention for things like data entry, filing papers, and making phone calls, and it can be slower and more prone to errors than automated processes.
Manual spinning – It refers to the process of forming metal shapes by applying pressure to a rotating metal blank using hand tools or a lathe, without the aid of automated machinery. It is a type of metal spinning where the operator controls the shaping process directly.
Manual switching – It is the act of using a physical device, operated by hand, to change the path of an electrical current or the flow of another substance. This needs a person to manually move a lever, rotate a knob, or press a button to turn a circuit on or off, connect a different power source, or change a connection between devices.
Manual welding – It is a welding operation which is performed and controlled completely by hand.
Manufactured aggregates – These are defined as materials produced from the thermal treatment or other processing of rocks or other materials, utilized in concrete to provide economic benefits, reduce embodied carbon di-oxide, improve sustainability, or achieve specific properties such as lighter weight or improved thermal characteristics.
Manufacturer drawing – Manufacturing drawing shows all the detailed dimensions and specifications of a single part so that it can be made with precision. Manufacturing drawing includes complete dimensions, the surface finish, welding information, plating, and any other requirements such as the deburring of the part. The quantities and complexity of the part influences how the manufacturer decides which method is the most cost effective to produce it.
Manufacturing – It is the conversion of materials into finished parts, products, and goods which have value to end-users. Manufacturing involves the design, development, implementation, control, operation, and maintenance of processes which facilitate and perform the conversion of starting materials into finished products having higher value.
Manufacturing chain – It is the entire sequence of processes, organizations, resources, and activities needed to create a product and deliver it to the end customer, from sourcing raw materials to final distribution. It includes all stages like procurement, production, quality control, warehousing, and logistics, and can involve multiple independent organizations.
Manufacturing constraint – It is a factor which limits the output of a production process, which can include a machine’s capacity, a specific process, material availability, or even external factors like supply chain issues or a shortage of skilled labor. These constraints dictate the overall pace of production and can hinder the organization from reaching its goals. Identifying and improving upon these constraints is the core principle of the Theory of Constraints (TOC) methodology.
Manufacturing control system – It is an integrated system which monitors, manages, and controls the complex processes involved in manufacturing, from raw materials to finished goods. It combines several technologies, like supervisory control and data acquisition (SCADA), to ensure efficient and consistent operations, manage resources, and track production. These systems are important for overseeing and coordinating activities such as machine control, material handling, quality assurance, and labour.
Manufacturing cost – It is the total expense incurred in producing a good, including all direct and indirect costs. It is comprised of three main components namely direct materials, direct labour, and manufacturing overhead.
Manufacturing cost estimation– It is the collection of methodologies and tools used to forecast the expected final cost of a manufactured product. Manufacturing cost is the sum of costs of all resources consumed in the process of making a product. The manufacturing cost is classified into five categories namely direct materials cost, energy cost, consumables cost, direct labour cost, and manufacturing overhead.
Manufacturing engineering – It is also known as production engineering. It is a branch of engineering which shares several common concepts and ideas with other branches of engineering such as mechanical, chemical, electrical, and industrial engineering. Manufacturing engineering needs the ability to plan the practices of manufacturing, to research and to develop tools, processes, machines, and equipment; and to integrate the facilities and systems for producing quality products with the optimum expenditure of capital. The manufacturing engineer’s main focus is to turn raw material into an updated or new product in the most effective, efficient, and economic way possible.
Manufacturing fixture – It is a custom-made tool used to securely hold, support, and position a work-piece during production operations like machining, welding, and assembly. Its main purpose is to ensure accuracy, consistency, and repeatability by placing the part in a precise and stable orientation, which also helps reduce setup time and worker effort. Unlike a jig, which guides a tool, a fixture focuses solely on holding the part firmly in place.
Manufacturing flexibility – It is the ease with which a process can be adapted to produce different products or variations of the same product. Process flexibility is influenced greatly by the time to set up or change tooling.
Manufacturing functions – These are the interrelated economic, technological, and organizational activities that directly transform raw materials and components into finished goods, including activities like process planning, fabrication, assembly, quality control, and logistics. These functions are essential for a production system of the organization and are part of a larger supply chain, managing the entire process from acquiring the raw materials to shipping the final product to customers.
Manufacturing information system (MIS) – It is a computer-based system which tracks the transformation of raw materials into finished goods to help managers optimize production and make better decisions. It automates activities by collecting and analyzing data on production processes, resources, scheduling, and quality control, with the goal of improving efficiency and reducing errors.
Manufacturing lead time – It is the time needed to process the product through the manufacturing plant. It is related to the process cycle time.
Manufacturing modelling – It is the process of using mathematical, digital, or physical representations to simulate, design, and optimize manufacturing systems and processes. This includes creating a digital twin of a physical factory to analyze efficiency, or using a 3D CAD (computer-aided design) model as the ‘source of truth’ for all product information, like dimensions, tolerances, and materials, in a method known as ‘model-based definition’ (MBD). This approach is used to predict system behaviour, reduce costs, improve accuracy, and streamline collaboration between different stages of production.
Manufacturing operations – These are the processes and activities involved in transforming raw materials into finished goods, covering everything from planning and sourcing to production, quality control, and distribution. The organization of these operations involves structuring the system to optimize production efficiency, maintain quality, and control costs, which includes managing resources, standardizing procedures, and utilizing data and key performance indicators (KPIs) to monitor and improve performance.
Manufacturing plant – It is an industrial facility, frequently a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process input raw materials into products and by-products.
Manufacturing process control – It is the systematic management and regulation of a production process to ensure consistent quality, efficiency, and safety. It involves using systems, sensors, and software to monitor and adjust variables in real-time, which can include everything from temperature and pressure to the speeds of conveyor belts, and is critical for reducing errors and improving output.
Manufacturing processes – The term manufacturing processes represents the main shape-generating methods such as casting, moulding, and forming processes, as well as traditional and non-traditional machining processes. These processes can be classified into three groups of processes namely (i) casting moulding, (ii) material removal, and (iii) forming. This classification provides a guide for the selection of the manufacturing processes which can be suitable contenders for a component. In majority of the cases, there are several processes which can be used for a component and final selection depends on a large number of factors, mainly associated with a range of technical capabilities and process economics, not the least component size, geometry, tolerances, surface finish, capital equipment, and labour costs. Some of the main process selection drivers are (i) product quantity, (ii) equipment costs, (iii) tooling costs, (iv) processing time, (v) labour intensity and work patterns, (vi) process supervision, (vii) maintenance, (viii) energy consumption, (ix) overhead costs, (x) material costs and availability, (xi) material to process compatibility, (xii) component form and dimensions, (xiii) tolerance requirements, (xiv) surface finish requirements, (xv) bulk treatment and surface engineering, (xvi) process to component variability. (xvii) process waste, and (xviii) component recycling. These drivers are not necessarily of equal importance or do not occur in a fixed sequence.
Manufacturing resource planning – It is a software system which expands the scope of material resource planning to involve other functions, such as finance and marketing, in a manufacturer’s production operations. It allows managers to accurately visualize scheduling and inventory and effectively monitor costs by leveraging real-time data to create a production schedule that optimally uses raw materials, machines and human resources.
Manufacturing stage – It is a specific step in the process of transforming raw materials or components into a finished product. It represents a phase where actions like production, testing, and quality assessment are conducted to advance the product through its lifecycle, from raw materials to a final good.
Manufacturing standards – These are the established criteria and requirements for production processes, materials, quality control, and documentation. These standards ensure consistent and reliable production by defining procedures, setting quality benchmarks (like materials testing or sterility), and providing detailed instructions for assembly and operations. They can include general guidelines, management system standards (such as ISO 9000), or specific requirements for product quality, safety, and compliance.
Manufacturing system – It is a collection of integrated equipment, human resources, and processes used to transform raw materials into finished goods. These systems include everything from planning and design to production, quality control, and distribution, with the goal of producing goods efficiently, profitably, and to customer specifications. Key components often include production machines, material handling systems, and computer control systems.
Manufacturing technology – It refers to the tools, machines, systems, and processes used in the production of goods to improve efficiency, quality, and productivity. This encompasses a wide range of applications, from traditional machinery to modern digital innovations like automation, data analytics, AI (artificial intelligence), and 3D printing. Its goal is to transform raw materials into finished products more effectively and reliably, enabling manufacturers to remain competitive in a global economy.
Manufacturing tolerance – It is the acceptable range of variation in a manufactured part’s dimensions, defined by its minimum and maximum limits. It is a permissible deviation from a specified or ‘ideal’ value since no manufacturing process can be perfectly precise. Tolerances ensure that a component still functions correctly and fit with other parts, even with these slight variations.
Manufacturing tool – It is a device or system used to shape materials, produce parts, or support the production process with precision and efficiency. Manufacturing tools can range from physical instruments like cutting tools and jigs to large-scale machinery like moulding systems and computer-controlled machines. They are fundamental for creating components and products across all industries.
Manufacturing unit – It is a facility, frequently a factory or plant, where raw materials and components are transformed into finished goods using machinery, labour, and several processes. This can involve the assembly of products, or chemical and biological processing, and is a key part of the economy which produces goods for consumers or other manufacturers.
Manure – It is organic matter which is used as organic fertilizer in agriculture. It improves soil and enhances plant growth. It provides nutrients and organic matter to the soil, benefiting both plant growth and soil health. Majority of manure consists of animal feces. Other sources include compost and green manure.
Mapping – It is the process of creating a visual or conceptual representation of relationships between different elements within a system, process, or physical space. This can involve creating diagrams, models, or maps to illustrate everything from manufacturing processes to site surveys and user interfaces. The goal is to improve clarity, facilitate analysis, and guide decision-making, which is necessary in fields like civil, and industrial engineering.
Mapping document – It is the output of a comparison between another resource classification system and United Nations Framework Classification (UNFC), or between that system and existing ‘Aligned systems’, which highlights the similarities and differences between the systems. A Mapping document can provide the basis for assessing the potential for the other system to become an Aligned system through the development of a Bridging document.
Map-staking – It is a form of claim-staking practiced in some jurisdictions whereby claims are staked by drawing lines around the claim-on-claim maps at a government office.
Maraging – It is a precipitation-hardening treatment applied to a special group of high-nickel iron-base alloys (maraging steels) to precipitate one or more intermetallic compounds in a matrix of essentially carbon-free martensite.
Maraging steels – These steels are high nickel steels with not less than 18 % nickel and are characterized by extreme high strength and toughness. Nickel normally encourages the formation of austenite in steels as opposed to carbides. Because of this, under the proper conditions high strength can be obtained by the transformation of austenite into martensitic type structures. The advantage of maraging steels is that this change is achieved as a result of a simple heat treatment which means that the problems of distortion normally associated with high temperature heat treatments are avoided. A typical heat treatment can involve heating to 820 deg C grade followed by air cooling (This avoids distortion which is associated with a faster rate cooling). The process is completed by ageing at a temperature in the range 450 deg C to 510 deg C.
Marangoni effect – It is also known as the Gibbs-Marangoni effect. It describes the flow of fluid along an interface between two fluids (or phases) caused by a surface tension gradient. This gradient can be because of the differences in temperature or concentration of a substance. Essentially, fluids with higher surface tension pull on fluids with lower surface tension, creating movement and convection.
Marangoni flow – It is fluid motion caused by a gradient in surface tension along a fluid interface, which can be driven by differences in temperature or chemical composition. This flow moves fluid from regions of low surface tension to regions of high surface tension.
Marangoni number (Ma) – It is a dimensionless quantity which compares the force of surface tension-driven flow (Marangoni effect) to the damping force of viscosity in a fluid. It represents the ratio of forces because of a surface tension gradient (caused by temperature or concentration differences) to viscous forces. A higher Marangoni number indicates that the Marangoni flow is stronger relative to the viscous forces, while a lower number means viscous forces dominate.
Marble – It is a metamorphic rock which is derived from the recrystallization of limestone under intense heat and pressure.
Marciniak bi-axial stretching test – In this test, a disk of the test material is stretched over a flat-bottomed punch of cylindrical or elliptical cross section. This creates uniform in-plane biaxial strain in the centre of the sample, with a strain ratio which is determined by the ratio of the major and minor diameters of the punch. Majority of the testing is performed with a cylindrical punch, which produces balanced biaxial stretching. The centre of the punch is hollowed out to eliminate friction in this area, and a spacer is placed between the sample and the punch. The spacer is a disk of material similar to that under test, with the same diameter, but with a hole at the centre. As the disk and spacer are stretched over the punch, the hole in the spacer enlarges, and the central part of the test sample is deformed in uniform in-plane biaxial stretching. The function of the spacer is to reverse the direction of the surface friction experienced by the sample. In the absence of the spacer, the surface friction opposes the movement of the sample over the punch and reduces the maximum strain level attainable. The spacer deforms more easily than the test sample because of the hole in the centre, and it exerts a frictional force on the sample directed outward over the punch radius. It is a method used in sheet metal forming to determine the material’s forming limit curve (FLC). It involves biaxially stretching a sheet metal sample using a cylindrical punch, with a carrier blank containing a hole to concentrate deformation and measure strain. This test helps predict the onset of necking and fracture during sheet metal forming processes.
Marciniak in-plane sheet torsion test – In this test, a flat 50 millimeters square sample is effectively divided into three zones namely (i) an inner circular zone, which is clamped, (ii) a ring-shaped middle zone, which surrounds the inner zone and is free to deform, and (iii) an outer ring-shaped zone, which is clamped. The inner zone is rotated in its plane relative to the outer zone, which deforms the middle zone in shear. The sample is deformed to fracture, and the angular rotations at two radii in the middle zone are measured by means of calibrated drums which rotate with the sheet.
Marforming process – It is a rubber-pad forming process developed to form wrinkle-free shrink flanges and deep-drawn shells. It differs from the Guerin process in that the sheet metal blank is clamped between the rubber pad and the blank-holder before forming begins.
Margin – It is the difference between the cost of an item and the price at which it is sold. The aim, hence, of the majority of the organizations is to make as much profit margin as possible while ensuring prices stay competitive. There is no denying that pricing is crucially important.
Marginal costs – Marginal costs are defined as the change in the total costs because of change in the volume of output by one unit. These costs are the variable costs associated with increasing output in the short run.
Marginal deposit – It is an ore-body of minimal profitability.
Marginal distribution – It is the probability distribution of a single variable from a set of variables, got by averaging over the other variables in the set. It focuses on the probability of one variable without considering the others, and it is calculated by summing or integrating the joint probability distribution over the variables a person wants to ‘marginalize out’ or ignore.
Marginal economic resources – Marginal economic resources are resources which at the time of determination are not economic, but border on being so. They can become economic in the near future as a result of changes in technological, economic, environmental and / or other relevant conditions.
Marginal producer – It is an organization which is barely profitable at current market prices, frequently because of the high production costs or being too small to benefit from economies of scale. They operate at a level where their revenue only just covers their costs, and they are the first to be squeezed out of the market if prices fall.
Marginal stability – It is said of a system which neither returns to its initial state when disturbed nor diverges to some unstable condition.
Margin of safety – It is that margin which is built into the safety analyses of the facility as set forth in the authorization basis acceptance limits. It is the margin needed in order to ensure safety. In engineering, the margin of safety is the factor of safety (strength of the material divided by the anticipated stress) minus one. It is something which is over and above what is strictly necessary and which is designed to provide for emergencies. It is a spare quantity or measure or degree allowed or given for contingencies or special situations. Margin of safety is also defined by the range between two conditions identified in a hazard control document such as the technical safety requirements. The first is the most adverse condition estimated or calculated in safety analyses to occur from an operational upset or family of related upsets. The second condition is the worst‐case value known to be safe, from an engineering perspective. This value is expected to be related to the condition at which some accident prevention or mitigation action is taken in response to the upset or accident, not the actual predicted failure point of some component.
Marine concrete – It is a specialized, high-durability concrete formulation designed to withstand the harsh and aggressive conditions of the marine environment, such as salt-water immersion, tidal fluctuations, and corrosive chemical agents like chloride ions. It is used in marine structures like piers, breakwaters, and offshore platforms and is engineered to resist degradation and corrosion for a longer service life.
Marine concrete structure – It is a concrete construction built in or near a marine environment, designed to be durable and robust in harsh conditions like saltwater and tidal fluctuations. These structures serve several purposes, from major port facilities like breakwaters and jetties to less visible applications like sea walls and underwater pipelines which use concrete for stability. They are engineered to withstand aggressive factors such as chemical erosion, physical abrasion, and the effects of tidal cycles to ensure their longevity.
Marine construction – It is the specialized field of building structures in or around bodies of water, such as oceans, rivers, and lakes. It involves creating durable infrastructure like docks, piers, seawalls, and offshore platforms, designed to withstand the challenges of the marine environment, such as salt-water, waves, and tides.
Marine corrosion – It includes the deterioration of structures and vessels immersed in seawater, the corrosion of machinery and piping systems which use seawater for cooling and other industrial purposes, and corrosion in marine atmospheres. Although salt water is normally considered to be a corrosive environment, it is not widely understood how corrosive salt water is in comparison to other environments, such as fresh (salt-free) water. When studying the corrosion rate of iron in aqueous (NaCl) solutions of different concentrations, it can be seen that the maximum corrosion rate occurs near 3.5 % sodium chloride concentration which is the approximate salt concentration of seawater. Further, there are other variables in seawater and in the marine environment which affect corrosion rates in different ways. Also, different corrosion behaviours are there for specific metals and alloys in the marine environment. The general marine environment includes a great diversity of sub-environments, such as full-strength open ocean water, coastal seawater, brackish and estuarine waters, bottom sediments, and marine atmospheres. Exposure of structural materials to these environments can be continuous or intermittent, depending on the application. Structures in shallow coastal or estuarine waters are frequently exposed simultaneously to five zones of corrosion. Beginning with the marine atmosphere, the structure then passes down through the splash, tidal, continuously submerged (or subtidal), and subsoil (or mud) zones. The relative corrosion rates frequently experienced on a steel structure passing through all of these zones are different.
Marine energy – It consists of useful energy from tides, waves, or salinity or temperature gradients of the ocean which can be extracted.
Marine renewable energy – It is the generation of electricity from naturally replenishing marine resources, including the movement of waves, tides, and ocean currents, as well as differences in water temperature and salinity. It also includes harnessing wind energy from offshore wind farms. This type of energy uses marine resources or space to produce power while reducing pollution and reliance on fossil fuels.
Marine structure – It is a human-made construction designed to function in or near water, such as an ocean, river, or sea. These structures are engineered to withstand challenging marine environments for purposes like transportation (piers, harbours), coastal protection (seawalls), and energy production (offshore platforms).
Mark – It is the damage in the surface of the product whose name is frequently described by source.
Mark, arbor – It is surface damage in the vicinity of a coil inside diameter caused by contact with a roughened, damaged, or non-circular arbor.
Mark, bearing – It is a depression in the extruded surface caused by a change in bearing length in the extrusion die.
Mark, bit – It is a line which is normally perpendicular to the rolling direction.
Mark, bristle – It is raised surface around 25 millimeters long, crimped wire shaped, and oriented in any direction.
Mark, carbon – It is gray or black surface marking caused by contact with carbon run-out blocks.
Mark, chatter (roll or leveler) – It is numerous intermittent lines or grooves which are normally full width and perpendicular to the rolling or extrusion direction.
Mark, drag – It is a surface area showing a scratch or abrasion resulting from contact of the hot extrusion with the press equipment or tooling or, in the case of multi-hole dies, with other sections as they exit the press.
Mark, edge follower – It is faint intermittent marks at the edge of a cold rolled product, which are normally perpendicular to the rolling direction. This mark is caused by action of devices designed to rewind coils without weave.
Market – It is the marketplace where the sale of organizational products and services is carried out.
Market acceptance – It refers to the degree of adoption of a new technology by consumers, investors, suppliers, and other stakeholders in the market. It encompasses the recognition of customer awareness and the acceptance process necessary for the development of innovative products.
Market analysis – In a feasibility report, market analysis is done to check the demand and supplies of the steel products included in the product mix in order to find the gap between demand and supplies. The positive gap between demand and supplies provides assurance that the product mix of the plant has got good demand and their marketability is not of a concern when the plant is commissioned.
Market impact – It is the effect which a market participant has when it buys or sells an asset. It is the extent to which the buying or selling moves the price against the buyer or seller, i.e., upward when buying and downward when selling. It is closely related to market liquidity. In several cases liquidity and market impact are synonymous.
Marketing – It is a key management discipline which ensures the organization (producer of goods and services) to interpret consumer desires and match, or exceed them. The marketing process is central to the performance of the organization, since it addresses the most important aspects of the market. It is about understanding the competitive market-place and ensures the organization to tap into key trends, to reach the customers with the right product at the right price, place, and time. Efficient marketing has led several organizations to success. Marketing refers to the organizations use to integrate their products or services with the wants or needs of a customer. Product marketing represents the intersection of the product, marketing, and sales teams to bring awareness to a product and how it can provide value to a customer.
Marketing management – It is an organizational discipline which focuses on the practical application of marketing techniques and the management of marketing resources and activities of the organization. It is the management of the marketing activities in the organization and includes management of the processes of planning, organizing, directing, motivating, coordinating, and controlling. It is the process of satisfying the needs and wants of the customers of the organization. It is an important function of the organization since it brings the organization closer to its customers and consists of establishing a marketing orientated organization where the emphasis is on the customer. It is a core component in the success of the organization.
Marketing people – These people refer to professionals who are responsible for gathering feedback from customers about products, and they play an important role in understanding customer needs and preferences to inform product design and development.
Market integration – It is the process of unifying separate markets into a single market by removing barriers, which causes prices in those markets to become more closely linked. This can happen through the free movement of goods and services, frequently facilitated by reducing tariffs or quotas, and can lead to increased competition and efficiency.
Market liquidity – It refers to the ease with which an asset can be bought or sold in a market without significantly affecting its price, indicating the depth and efficiency of trading. In simpler terms, it is about how quickly and easily a person can convert an asset to cash without a substantial price drop.
Market manipulation – It is an action which causes a market price to deviate from what is supposed to occur under competitive conditions, including the exercise of market power, anti-competitive behaviour, and strategic resource scheduling which exploits rule flaws to the detriment of the market.
Market mechanism – It is a mechanism by which the use of money exchanged by buyers and sellers with an open and understood system of value and time trade-offs in a market tends to optimize distribution of goods and services in at least some ways. The mechanism can exist in free markets or in captive or controlling markets seek to use supply and demand, or some other form of charging for scarcity, to choose among production possibilities.
Market monitoring – It is the continuous process of collecting, analyzing, and interpreting data to observe and understand a market’s conditions, performance, and behaviour. The goal is to identify trends, risks, and opportunities to inform decision-making, ensure fairness and stability, and help organizations stay competitive. It can involve tracking prices, analyzing financial market data, or assessing a market for regulatory compliance or program impact.
Market order – It is an order to buy or sell at the best price available. In absence of any specified price or limit, an order is considered to be ‘at the market’.
Market player – Market player is any individual, organization, or entity involved in a specific market, such as a product market. These players are the buyers and sellers who interact to trade goods, services, or financial instruments, ultimately influencing market prices and liquidity. Examples include producers, consumers, retailers, investors, and financial intermediaries like brokers.
Market pressure – It refers to the external factors which influence a market, including competitive dynamics, demand and supply levels, and industry trends, which force companies to adjust their strategies, pricing, and compensation to remain competitive and successful. For example, an organization faces market pressure to lower its prices if a competitor offers a similar product at a lower cost, and an organization needs to match industry compensation standards to attract talent.
Market price – It is the price at which transactions occur in a trading session, determined by the supply and demand dynamics of buy and sell orders, and can vary based on the specific arrangements between involved parties in bilateral agreements.
Market research – It is the systematic process of gathering, analyzing, and interpreting information about a market, its customers, and competitors to help organizations make informed decisions and develop successful organizational strategies. It provides insights into consumer needs, preferences, and behaviours, as well as market trends and competitive landscapes, guiding decisions on product development, pricing, and marketing campaigns.
Market share – It is the percentage of total sales in an industry or market which a specific organization earns during a given period. It is a key metric in marketing to measure the performance of the organization and competitiveness against rivals, and can be calculated by dividing the organizational sales by the total sales of the entire market.
Marketing strategy – It is the organizational long-term, high-level plan for reaching potential customers and turning them into buyers of its products or services. It involves identifying a target audience, defining a unique value proposition, and outlining the specific tactics to promote the brand and build a competitive advantage. The strategy sets the objectives, while the marketing plan details the specific actions needed to achieve them.
Market survey – It is a marketing research tool used to gather direct, firsthand feedback from a target audience by asking them questions about their preferences, experiences, and behaviours. This collected data is used to inform decisions regarding product development, marketing strategies, and overall organizational growth by providing insights into customer attitudes and market trends.
Mark, handling – For rolled products, it an area of broken surface which is introduced after processing. The mark normally has no relationship to the rolling direction. For extrusions, it is the damage which can be imparted to the surface during handling operations.
Mark, heat treat contact – It is brownish, iridescent, irregularly shaped stain with a slight abrasion located somewhere within the boundary of the stain. It is a result of metal-to-metal contact during the quenching of solution heat treated flat sheet or plate.
Mark, inclusion – It is the appearance of surface where actual inclusion or the void it left is observed.
Marking – It is the process of applying identification codes, symbols, or instructions directly onto a product or its packaging to ensure proper handling, tracking, and compliance.
Markings, product – These are marks and symbols which provide a unique and quick identifier for a product. Markings consist of a special symbol, word, or picture which the organization uses for the product identification.
Mark, knife – It is a continuous scratch (which also can be creased) near a slit edge, caused by sheet contacting the slitter knife.
Mark, knock-out – It is a small solid protrusion or circular fin on a forging or a casting, resulting from the depression of a knock-out pin under pressure or inflow of metal between the knock-out pin and the die or mould.
Mark, leveler chatter – It is numerous intermittent lines or grooves which are normally full width and perpendicular to the rolling or extrusion direction.
Mark, metal-on-roll – For rolled products, it is a sharply defined surface impression on the metal which can be caused by a blow from another object. For extrusions, it is a synonym for handling mark.
Mark, mike – It is a narrow continuous line near the rolled edge caused by a contacting micro-meter.
Markov chain – It is also called Markov process. It is a stochastic process describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event. Informally, this can be thought of as, ‘What happens next depends only on the state of affairs now’. A countably infinite sequence, in which the chain moves state at discrete time steps, gives a discrete-time Markov chain (DTMC). A continuous-time process is called a continuous-time Markov chain (CTMC). Markov chains have several applications as statistical models of real-world processes. They provide the basis for general stochastic simulation methods known as Markov chain Monte Carlo, which are used for simulating sampling from complex probability distributions.
Markov decision process – It is a mathematical framework for modeling decision-making in situations with uncertainty, and it can be applied to marketing by using it to create optimal marketing strategies. It defines states (like customer segments), actions (like sending a specific promotion), and rewards (like purchase or engagement), with the goal of finding a policy (a set of rules for choosing actions) which maximizes long-term reward, such as customer lifetime value. This framework helps organizations make sequential decisions over time by learning from the outcomes of previous actions.
Markov parameter – It is a component of a Markov chain model, which refers specifically to the transition probabilities which quantify the likelihood of a customer moving between different defined states (e.g., from ‘awareness’ to ‘Consideration’ to ‘purchase’ , or between different brands or marketing channels).
Mark, pinch – It is a sharp deviation from flat in the sheet which is transferred from processing equipment subsequent to the roll bite.
Mark, roll – For rolled products, it is a small repeating raised or depressed area caused by the opposite condition on a roll. The repeat distance is a function of the offending roll diameter. For extrusions, it is a longitudinal groove or indentation caused by pressure from contour rolls as a profile (shape) passes through them for dimensional correction.
Mark, roll bruise – It is a greatly enlarged roll mark with a very shallow height or depth.
Mark, roll skid – It is a full-width line perpendicular to the rolling direction and repeating as a function of a work roll diameter.
Mark, rub – It is a large number of very fine scratches or abrasions. A rub mark can occur by metal-to-metal contact, movement in handling, and movement in transit.
Mark, snap – It is a band-like pattern around the full perimeter of an extruded section and perpendicular to its length. A snap mark can occur whenever there is an abrupt change in the extrusion process.
Mark, stop – It is a band-like pattern around the full perimeter of an extruded section and perpendicular to its length. A stop mark occurs whenever the extrusion process is suspended.
Mark, stretcher jaw – It is a cross-hatched appearance left by jaws at the end(s) of metal which has been stretched. These marks are seen if insufficient metal has been removed after the stretching operation.
Mark, tab – It is a bend, crease, wrinkle, or departure from flat, occurring perpendicular to the slit edge of a coil and which are repetitive in nature, with severity decreasing as the distance increases in the coil from the original source. Normally, it is found on the inside diameter of a coil but can appear on the coil outside diameter as a result of a prior winding operation.
Mark, tail – It is a greatly enlarged roll mark with a very shallow height or depth.
Mark, take-up – It is a short longitudinal indentation parallel to the rolling direction.
Mark, traffic – It is the abrasion which results from relative movement between contacting metal surfaces during handling and transit. A dark colour from the abrasively produced aluminum oxide is normally observed in case of aluminum metal. A mirror image of a traffic mark is observed on the adjacent contacting surface.
Mark, whip – It is a surface abrasion which is normally diagonal to the rolling direction. It is caused by a fluttering action of the metal as it enters the rolling mill.
Marquenching – It is a hardening procedure in which an austenitized ferrous material is quenched into an appropriate medium at a temperature just above the martensite start temperature of the material, and held in the medium until the temperature is uniform throughout, although not long enough for bainite to form, then cooled in air. The treatment is frequently followed by tempering. When the process is applied to carburized material, the controlling martensite start temperature is that of the case. This variation of the process is frequently called marquenching.
Mars-van Krevelen mechanism – It refers to a process in selective oxidation reactions where lattice oxygen atoms are transferred to adsorbed organic molecules, leading to the reduction of the oxide surface and subsequent reoxidization through the migration of adsorbed oxygen species to vacant sites on the catalyst surface.
Martempering – It is a hardening process in which an austenitized ferrous material is quenched into an appropriate medium at a temperature just above the martensite start temperature of the material, held in the medium until the temperature is uniform throughout, although not long enough for bainite to form, then cooled in air. The treatment is frequently followed by tempering. When the process is applied to carburized material, the controlling martensite start temperature is that of the case. This variation of the process is frequently called marquenching.
Martensite – It is a generic term for micro-structures formed by diffusion-less phase transformation in which the parent and product phases have a specific crystallographic relationship. Martensite is characterized by an acicular pattern in the micro=structure in both ferrous and non-ferrous alloys. In alloys where the solute atoms occupy interstitial positions in the martensitic lattice (such as carbon in iron), the structure is hard and highly strained, but where the solute atoms occupy substitutional positions (such as nickel in iron), the martensite is soft and ductile. The quantity of high-temperature phase which transforms to martensite on cooling depends to a large extent on the lowest temperature attained, there being a rather distinct beginning temperature (Ms) and a temperature at which the transformation is essentially complete (Mf).
Martensite deformation – It refers to the changes in shape and structure which occur when martensite, a hard and brittle phase in steel, is subjected to stress or strain. This deformation can involve both plastic deformation and a transformation back to the original austenite phase (in shape memory alloys) or further transformation to other phases like bainite.
Martensite finish (Mf) temperature – It is the temperature at which the martensitic transformation is completed during cooling. It is the temperature at which the transformation of austenite into martensite finishes, meaning no further austenite transforms into martensite upon further cooling. This temperature is crucial in heat treatment processes for steels.
Martensite formation – It is a diffusion-less transformation where austenite in steel rapidly cools, or ‘quenches,’ causing its crystal structure to change into a hard, brittle, non-equilibrium phase with a body-centered tetragonal or body-centered cubic structure. This rapid cooling traps carbon atoms in the iron lattice, preventing them from diffusing and forming the characteristic needle or lath-like micro-structure of martensite.
Martensite fraction – It is the proportion of martensite within a material’s micro-structure, frequently expressed as a percentage or volume fraction. It is a critical property, particularly for steels, since it influences mechanical characteristics like strength and hardness. A higher martensite fraction normally leads to increased yield and tensile strength, while uniform elongation decreases.
Martensite island – It is a localized, hard region within steel which contains a mixture of martensite and austenite. These islands form during the cooling process, frequently from untransformed austenite, and considerably affect the material’s mechanical properties, such as its strength and work hardening behaviour. These islands are a key micro-structural feature in steels like dual-phase (DP) steel, and their presence can create ‘local brittle zones’ where cracks can initiate, especially at their boundaries with the softer matrix.
Martensite plate – It is a crystal structure which forms in high-carbon steels when austenite is rapidly cooled. It is characterized by a three-dimensional plate-like geometry, appearing as a zigzag array of needle-like shapes under a light microscope. This structure is a result of a diffusion-less shear transformation which results in a super-saturated solution of carbon in a highly strained body-centred tetragonal (BCT) iron lattice.
Martensite start (Ms) temperature – It is the temperature at which the austenite phase in steel begins to transform into martensite during rapid cooling. It is the temperature where the diffusion less, athermal transformation of austenite to martensite starts upon cooling.
Martensite temperature range – It is the interval between the martensite start (Ms) and the martensite finish (Mf) temperatures.
Martensite transformation – It is a diffusion-less, solid-state process where a material, most notably austenite in steel, rapidly transforms into a new crystal structure called martensite upon rapid cooling. This rapid change occurs because of the shear displacements rather than the slow, long-range diffusion of atoms. The resulting martensite is a very hard and brittle, supersaturated solid solution.
Martensitic – It is a platelike constituent having an appearance and a mechanism of formation similar to that of martensite.
Martensitic grades – These are a type of stainless steel defined by their ability to be hardened through heat treatment. They are characterized by a metallurgical structure called martensite, achieved by heating and rapid cooling (quenching). This process results in high strength, hardness, and wear resistance, making them suitable for applications like knife blades and springs.
Martensitic hardening – It is a heat treatment process used to increase the hardness and strength of metals, particularly steels, by transforming their microstructure into a hard, brittle phase called martensite. This transformation is achieved by rapidly cooling (quenching) a heated metal, preventing the formation of softer microstructures.
Martensitic microstructure – It is a phase in metals, particularly steels, formed by the rapid cooling of austenite in a diffusion-less, shear-like transformation. This process locks carbon atoms into the iron lattice, creating a body-centred tetragonal (BCT) crystal structure that is very hard but brittle. The specific arrangement can be a lath structure (low carbon) or a plate structure (high carbon).
Martensitic stainless steels – These are essentially alloys of chromium and carbon which possess a distorted body-centered cubic (bcc) crystal structure (martensitic) in the hardened condition. They are ferro-magnetic, hardenable by heat treatments, and are normally resistant to corrosion only to relatively mild environments. Chromium content is normally in the range of 10.5 % to 18 %, and carbon content can exceed 1.2 %. The chromium and carbon contents are balanced to ensure a martensitic structure after hardening. Excess carbides can be present to increase wear resistance or to maintain cutting edges, as in the case of knife blades. Elements such as niobium, silicon, tungsten, and vanadium can be added to modify the tempering response after hardening. Small quantities of nickel can be added to improve corrosion resistance in some media and to improve toughness. Sulphur or selenium is added to some grades to improve machinability.
Martensitic steels – To create martensitic steels, the austenite which exists during hot rolling or annealing is transformed almost entirely to martensite during quenching on the runout table or in the cooling section of the continuous annealing line. The martensitic steels are characterized by a martensitic matrix containing small amounts of ferrite and / or bainite. Within the group of multi-phase steels, martensitic steels show the highest tensile strength level. This structure can also be developed with post forming heat treatment. Martensitic steels provide the highest strengths, up to 1,700 MPa ultimate tensile strength. Martensitic steels are frequently subjected to post quench tempering to improve ductility, and can provide adequate formability even at extremely high strengths.
Martensitic transformation – It is a reaction which takes place in some metals on cooling, with the formation of an acicular structure called martensite.
Martensitic transition – It is a type of solid-state phase transformation where a material changes its crystal structure without diffusion of atoms, meaning atoms move in a coordinated, collective manner. This is a diffusion-less process, frequently induced by rapid cooling, which involves a rapid and instantaneous change in atomic positions. It results in a new, displacive structure called martensite, and can be accompanied by unique properties like the shape memory effect.
Martinelli correlation – It is frequently referred to as the Lockhart-Martinelli correlation, is an empirical method in fluid dynamics used to calculate the pressure drop in two-phase flow (like liquid and gas) through pipes. It is based on the assumption which the static pressure drop for the liquid phase is equal to the static pressure drop for the gas phase, and relates the two-phase friction multiplier to the Lockhart-Martinelli parameter, which is the square root of the ratio of the pressure drop of the liquid phase to that of the gas phase if each flowed alone.
Martinelli parameter – It is a dimensionless quantity, frequently called the Lockhart-Martinelli parameter, used in two-phase flow to characterize the flow regime. It is defined as the ratio of the pressure gradient of the liquid phase to the pressure gradient of the gas phase, based on the assumption that the two phases are flowing separately. The parameter can be calculated using the flow rates and densities of the liquid and gas phases.
Marx generator – It is a kind of circuit for generating very high direct current voltage pulses.
Maser – It is a device which produces microwave energy in a similar manner to a laser.
Mash seam welding – It is a type of resistance seam welding where two work-pieces are overlapped and then joined by applying pressure and heat, typically through rotating electrodes, to create a continuous weld seam. It is characterized by a lap joint where the overlapped material is squeezed and fused together, frequently resulting in a smooth, crevice-free joint.
Mask – In thermal spraying, mask is a device for protecting a surface from the effects of blasting and / or coating or adherence of a spray deposit. Masks are normally either reusable or disposable.
Masking –This is the process of using a material to produce intentionally ungalvanized areas, typically used in areas which are to be welded, on faying surfaces, or areas where the galvanized coating is not necessary for uniform corrosion protection.
Masking effect – It refers to the phenomenon where the visibility of noise is influenced by the presence of a spatial edge, with variations depending on edge contrast and proximity to the target.
Masonry – It is a construction technique where individual units like bricks, stones, or concrete blocks are stacked and bound together with mortar to create structures such as walls, arches, and columns. It is valued for its durability and aesthetic appeal and can be used for both load-bearing and non-load-bearing applications.
Masonry application – It is the use of individual units like bricks, stone, or concrete blocks, bound together by mortar, to construct both structural and non-structural elements of a building or other structure. This can include load-bearing walls, foundations, and columns, as well as decorative or functional features such as fireplaces, chimneys, arches, and retaining walls.
Masonry block – It is also known as a concrete masonry unit (CMU). It is a rectangular building unit made from concrete, aggregates, and water, used in masonry construction. In construction, these blocks are laid and bound together with mortar to form durable structures like walls, foundations, and retaining walls. They provide strength, durability, and versatility, with common types including solid, hollow, and lightweight options like autoclaved aerated concrete (AAC) blocks.
Masonry cement – It is a hydraulic cement blend specifically designed for masonry construction to bond building units like brick, block, and stone together. It is a pre-mixed material which includes Portland cement, air-entraining agents, and fillers like limestone to improve properties such as plasticity, water retention, and workability. This formulation results in a durable mortar which provides strength and structural integrity while also improving the appearance and longevity of the finished structure.
Masonry construction – It is a building technique where individual units, such as bricks, stones, or concrete blocks, are laid and bound together with mortar to form structures. This method creates durable, strong, and often fire-resistant buildings and features like walls, foundations, and chimneys.
Masonry dam – It is a dam built from masonry materials like stone, brick, or concrete blocks, frequently joined with mortar. These dams function as gravity dams, resisting the pressure of the water by their own weight and mass. They are used for water storage, flood control, and power generation, but their construction is labour-intensive and less common today than modern dam types.
Masonry structure – It is a building or construction made of individual units, such as bricks, stones, or concrete blocks, which are laid and bound together with mortar. This traditional technique is valued for its structural strength, durability, and aesthetic appeal, and is used in everything from simple walls to elaborate buildings.
Mass – It is an intrinsic property of an object. It quantifies the quantity of matter or substance in the object, and its resistance to acceleration. It is a scalar quantity, meaning it has only magnitude. It can be experimentally defined as a measure of the object’s inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object’s mass also determines the strength of its gravitational attraction to other bodies. The SI (International System of Units) base unit of mass is the kilogram (kg). Mass is frequently confused with weight, but weight is a force, while mass is a measure of inertia.
Mass absorption coefficient – It is the linear absorption coefficient divided by the density of the medium.
Mass acceleration – It refers to the acceleration experienced by an object because of the application of a force, which is determined by its mass. Specifically, a larger mass needs a higher force to achieve the same acceleration, as described by the relationship Force = Mass × Acceleration (F = ma).
Mass balance, material balance – It is an application of conservation of mass. By accounting for material entering and leaving a system, mass flows can be identified which are otherwise unknown, or difficult to measure without this technique. The exact conservation law used in the analysis of the system depends on the context of the problem, but all revolve around mass conservation, i.e., that the matter cannot destroyed or be created spontaneously.
Mass concentration – In a slurry, it is the mass of solid particles per unit mass of mixture, expressed in percent.
Mass concrete – It is a large volume of concrete with dimensions so great that the heat generated during cement hydration can cause thermal stresses and cracking if not managed. Structures like dams, mat foundations, and thick bridge piers are examples of mass concrete projects where temperature control is crucial to prevent cracking.
Mass conservation law – It states that in a closed system, mass can neither be created nor destroyed during a chemical or physical change. This means the total mass of the reactants before a reaction equals the total mass of the products after the reaction, since atoms are simply rearranged, not created or destroyed.
Mass-conserving process – It is a manufacturing process in which the mass of the starting material is approximately equal to the mass of the final product or part. Examples are casting, precision forming, and powder processes.
Mass customization – It is the organizational strategy which combines the efficiency of mass production with the flexibility of creating products that are personalized for individual customers. This allows organizations to produce a large number of goods at a low cost while still meeting the diverse needs and preferences of each consumer, frequently through options like adaptive customization (pre-defined choices) or collaborative customization (co-design with the customer).
Mass defect – It is the difference between the total mass of the individual protons and neutrons in an atom’s nucleus and the actual measured mass of the nucleus itself. This ‘missing’ mass is converted into energy, known as the nuclear binding energy, which holds the nucleus together, as per the Einstein’s equation, E = m x (c square), where ‘E’ is energy, ‘m’ is mass, and ‘c’ is the speed of light.
Mass density – It is the mass per unit of volume of the material.
Mass density (or density) of the steam – It is the specific mass of the steam in a volume of 1 cubic metre.
Mass effect – It normally refers to the influence of mass on a component’s properties or behaviour, particularly during manufacturing processes like casting or heat treatment, or when considering fluid dynamics. It can also refer to the ‘added mass’ effect, where a body moving through a fluid appears to have a larger mass because of the fluid it is accelerating.
Mass exchange – It is a process where mass is transferred from one point to another, typically from a region of high concentration to one of low concentration, driven by a concentration difference. It frequently refers to the specific, selective transfer of certain components from a ‘rich phase’ to a ‘lean phase’ using a mass-separating agent, such as in processes like absorption, adsorption, or ion exchange.
Mass finishing – It normally involves loading components to be finished into a container together with some abrasive media, water, and compound. Action is applied to the container to cause the media to rub against the surfaces, edges, and corners of the components, or for components to rub against each other, or both. This action can deburr, generate edge and corner radii, clean the parts by removing rust and scale, and modify the surface stress. The basic mass finishing processes include (i) barrel finishing, (ii) vibratory finishing, (iii) centrifugal disc finishing, (iv) centrifugal barrel finishing, (v) spindle finishing, and (vi) drag finishing. Mass finishing is a simple and low-cost means of deburring and surface conditioning components. Consistent results from part to part and batch to batch are normally ensured. All metals and several non-metals in a variety of sizes and shapes can be handled. Processes range from heavy radiusing and grinding operations to very fine finishing. A basic advantage of mass finishing is that the action is effective on all the surface edges and corners of the part. Normally, preferential treatment to one area is impossible. Action is greater on corners than other similarly exposed surfaces. Action in holes and recesses is less than on exposed areas.
Mass flow controller – It is a device which measures and automatically regulates the flow rate of liquids or gases by their mass, rather than volume, ensuring a consistent flow regardless of pressure and temperature changes. It does this by using a sensor to measure the mass flow and a control valve to adjust it to a set point, which is important for high-precision applications like semi-conductor manufacturing, chemical processes, and laboratory work.
Mass flow rate – It refers to the quantity of mass of a substance which passes through a given area per unit of time. It is a measure of how much mass is moving across a particular point or within a specific volume over a specific period, and is crucial in fluid dynamics and thermodynamics. The standard SI unit for mass flow rate is kilograms per second.
Massive sulphide – It is relatively dense, fine grained, sometimes bedded, sulphide mineralization, normally lens-shaped and stratiform, i.e., restricted to a particular geologic horizon.
Mass movement – It is also known as mass wasting. It refers to the downslope movement of rock, soil, and other materials under the influence of gravity, without the aid of a transporting medium like water, ice, or wind.
Mass number – It is the number of protons plus neutrons in the nucleus of an atom.
Mass production – It is a system of production where products are produced at large scale on continuous basis. Production is done in anticipation of market demand, not on the basis of specific order of the customer.
Mass-reducing process – It is a manufacturing process in which the mass of the starting material is higher than the mass of the final product or part, and forming takes place by the removal of material, e.g., machining.
Mass spectrometer – It is an apparatus for measuring the masses of isotopes, molecules, and molecular fragments by ionizing them and determining their trajectories in electric and magnetic fields.
Mass spectrometry – It is an analytical technique for identification of chemical structures, analysis of mixtures, and quantitative elemental analysis, based on application of the mass spectrometer. This analytical technique is used to measure the mass-to-charge ratio of ions. The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio.
Mass spectrum – It is a record, graph, or table which shows the relative number of ions of different masses which are produced when a given substance is processed in a mass spectrometer. It is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds.
Mass-spring system – It is a model consisting of a mass attached to a spring, which demonstrates oscillatory motion. When the mass is displaced from its equilibrium position, the spring exerts a restoring force, causing the mass to move back and forth in a pattern known as simple harmonic motion, provided friction is ignored.
Mass-to-charge ratio (m/Q) – It is a physical quantity relating the mass (quantity of matter) and the electric charge of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electro-dynamics of charged particles, e.g. in electron optics and ion optics. The importance of the mass-to-charge ratio, as per the classical electro-dynamics, is that two particles with the same mass-to-charge ratio move in the same path in a vacuum, when subjected to the same electric and magnetic fields.
Mass to energy conversion – It is the process where mass is transformed into energy, as described by Einstein’s equation, E = m x (c square), where ‘E’ represents the equivalent energy, ‘m’ represents the mass which is converted, and ‘c’ c is the speed of light (3 x 10 to the power 8meters per second), a very large constant. This principle, known as mass-energy equivalence, demonstrates that mass and energy are interchangeable, meaning a small quantity of mass can be converted into a tremendous amount of energy. This phenomenon is most evident in nuclear reactions like fission and fusion.
Mass transfer – It is the net movement of mass from one location (normally meaning stream, phase, fraction, or component) to another. Mass transfer occurs in several processes, such as absorption, evaporation, drying, precipitation, membrane filtration, and distillation. Mass transfer is used by different scientific disciplines for different processes and mechanisms. The phrase is normally used in engineering for physical processes which involve diffusive and convective transport of chemical species within physical systems.
Mass transfer coefficient – It is a proportionality constant which relates the rate of mass transfer to the concentration driving force and the area of contact between phases. It essentially quantifies how quickly a substance moves from one phase to another. The coefficient is a crucial parameter in understanding and designing processes that involve mass transfer, like distillation, absorption, and extraction. Mass transfer coefficient is a crucial parameter in the study of mass transfer processes, which describe how substances move from one phase to another, such as from a gas to a liquid or between two immiscible liquids. It quantifies the rate at which mass is transferred per unit area per unit concentration difference.
Mass transit – It is the transportation facilities designed to transport large groups of people in a single vehicle such as buses or trains.
Master alloy – It is an alloy, rich in one or more desired addition elements, which are added to a metal melt to raise the percentage of a desired constituent.
Master alloy powder – It is a pre-alloyed metal powder of high concentration of alloy content, designed to be diluted when mixed with a base powder to produce the desired composition.
Master block – It is a forging die block used mainly to hold insert dies.
Master controller – It is a central device which directs and coordinates the operation of multiple components or systems from a single point. It sends commands and signals to manage functions like speed, direction, and other operational parameters to ensure components work together correctly. Applications include controlling cranes, elevators, and railway locomotives, as well as managing industrial automation and computer networks.
Master control relay (MCR) – It has the purpose of shutting down the entire panel if the master control relay is not engaged.
Master data management (MDM) – It acts as the single source of reference, capable of integrating all records and data from distributed and diverse systems across an organization for unmatched consistency. The purpose of master data management is to help the organization to improve the quality of the critical information / data such as product data, customer data, employee data, location data, and their quality across the entire organization.
Master encoder – In rolling mill shears, it is the incremental encoder connected to the stand motor and is used to detect the material position.
Master mould – It is a template used to replicate patterns, typically made from rigid materials, which can create moulds of elastomeric polymers for mass-producing patterned features on substrates.
Master pattern – In foundry practice, it is a pattern embodying a double contraction allowance in its construction. It is used for making castings to be used as patterns in production work.
Master processor – It is the main controller in a multi-processor system which manages and directs the work of other, ‘slave’ processors. It handles tasks like resource scheduling, initiating transfers, and maintaining system status, while the slave processors execute the tasks assigned to them by the master.
Master production schedule – It is a detailed plan which outlines which products are to be produced, in what quantities, and when. It is an important tool for manufacturing organizations to balance customer demand with production capacity, ensuring they can meet deadlines while minimizing costs and overstock. The master production schedule acts as a communication link between sales and manufacturing, influences material requirements planning (MRP), and provides a roadmap for production activities.
Master product model – It is an approach toward design in which the product design is centred on an information-rich computer model which supports not only the physical design, but analysis, testing, design, optimization, simulation, prototyping, manufacturing, and maintenance.
Mastic asphalt – It is a dense, waterproof, and durable mixture of bitumen, fine aggregates (like sand), and filler materials which is applied hot to create a seamless and impermeable surface. It is used in construction for its high durability, water resistance, and ability to withstand wear, particularly on roads, bridges, roofs, and floors. Unlike conventional asphalt, it has very low void content and can be laid in a self-compacting manner without needing mechanical compaction after spreading.
Mat – It is a fibrous material for reinforced plastic consisting of randomly oriented chopped filaments, short fibres (with or without a carrier fabric), or swirled filaments loosely held together with a binder. It is available in blankets of different widths, weights, and lengths. It is also a sheet formed by filament winding a single-hoop ply of fibre on a mandrel, cutting across its width and laying out a flat sheet.
Match – It is a condition in which a point in one metal-forming or forging die half is aligned properly with the corresponding point in the opposite die half within specified tolerance.
Matched edges – It consists of two edges of the die face which are machined exactly at 90-degree to each other, and from which all dimensions are taken in laying out the die impression and aligning the dies in the forging equipment.
Matched metal moulding – It is a reinforced plastics manufacturing process in which matching male and female metal moulds are used (similar to compression moulding) to form the part, with time, pressure, and heat.
Matched set drawing – It defines items which are matched and for which replacement as a matched set is essential. It is prepared when the required dimensions, tolerances, or other characteristics of items can only be specified in terms of the matched relationship. This includes items which are inter-changeable only as a set because of special requirements for machining, electrical characteristics, performance, etc. It includes (i) physical or functional mating characteristics of the matched items (set), (ii) unique identifier assigned to each of the parts and to the matched set, and (iii) discrete identification marking of the matched set.
Matching draft – It is the adjustment of draft angles (normally involving an increase) on parts with asymmetrical ribs and sidewalls to make the surfaces of a forging meet at the parting line.
Match plate – It is a plate of metal or other material on which patterns for metal casting are mounted (or formed as an integral part) to facilitate moulding. The pattern is divided along its parting plane by the plate.
Material – It is a substance or mixture of substances which constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function.
Material anisotropy – It is the property of a material where its physical properties, such as strength or conductivity, vary depending on the direction of measurement. Unlike isotropic materials, which have uniform properties in all directions, anisotropic materials behave differently depending on their orientation. This is frequently because of the internal structure, such as crystal orientation, the presence of fibres, or processing techniques like rolling.
Material balance – It is also known as a mass balance. It is an accounting of all materials entering and leaving a system, ensuring that the total mass remains constant, following the law of conservation of mass. The material balance method refers to the calculation of the input and output of substances based on the law of conservation of mass by analyzing the materials used in the production and chemical reaction processes.
Material behaviour – It is how a material responds to applied forces, which can include its mechanical and thermal properties. It is characterized by the relationship between stress and strain, and is influenced by factors like composition, microstructure, and environmental conditions. Key aspects include elasticity (ability to return to original shape) and plasticity (permanent deformation).
Material characterization – It is the use of different analytical methods (spectroscopy, microscopy, and chromatography etc.) to describe those features of composition (both bulk and surface) and structure (including defects) of a material which are significant for a particular preparation, study of properties, or use. Test methods which yield information mainly related to materials properties, such as thermal, electrical, and mechanical properties, are excluded from this definition.
Material combination – It is the strategic selection and integration of two or more different materials to create a product with new or improved properties. This can refer to physical pairings in products like composite materials (e.g., fibre-glass) or chemical combinations, such as when elements react to form a new compound (e.g., sodium and chloride to make salt). It also applies to the design and aesthetic use of materials together.
Material compatibility – It is the ability of different materials to coexist and function together without adverse reactions, degradation, or performance loss. It is crucial in engineering and design to ensure that materials in a system can withstand environmental conditions and stresses without causing issues like corrosion, chemical reactions, or premature failure.
Material component – It is a substantial part of a larger object, a specific material needed for production or maintenance, or an interactive building block for a user interface, depending on the context.
Material composition – It is a description of the specific elements, compounds, or substances which make up a material or product and their proportions. It reveals an object’s inherent nature, providing insights into its properties like strength and durability, and can help trace its origins or the manufacturing process.
Material cycle – It refers to the comprehensive process of extracting, processing, and utilizing raw materials from the earth, which subsequently undergoes further processing and manufacturing to create finished products, eventually leading to their disposal and potential recycling to reclaim valuable materials.
Material database – It is an organized system for storing and accessing data about materials. It compiles information such as physical properties, chemical composition, mechanical and thermal characteristics, and manufacturing details to provide a searchable collection for designers, engineers, and researchers.
Material data sheet (MDS) – It defines the minimum requirements for the materials, i.e. chemical specifications, manufacturing, qualification of supplier, mechanical testing and properties, non-destructive examination, repair, marking and certification.
Material derivative – It is the time rate of change of a physical quantity for a material particle moving within a flow. It represents the total change experienced by a particle as it moves through both space and time, and is a key concept in continuum mechanics and fluid dynamics. It can be broken down into a local rate of change and a convective rate of change caused by the particle’s movement through spatial gradients.
Material dispersion – It is the phenomenon where different wavelengths of light travel at different speeds through a material, causing a light pulse to spread out over time. This occurs since the material’s refractive index changes with wavelength. As a result, different colours within a light pulse arrive at their destination at slightly different times, leading to a broader pulse, which is a form of chromatic dispersion.
Material dissolution – It is defined as the process by which material is removed from a work-piece surface through electro-chemical reactions, influenced by factors such as discharge time and the interelectrode gap distance. It progresses from the outside toward the center of the electrode-facing area, with the dissolution rate depending on the dissolution time and the characteristics of the material.
Material distribution – It refers to the allocation of materials in a design process based on the property constraints of different parts.
Material ductility – It is the ability of a material to undergo substantial plastic deformation, such as stretching or bending, before it fractures. This property allows a material to be drawn into a thin wire under tensile stress without breaking. Ductile materials can deform substantially, providing a warning of failure, whereas brittle materials fracture with little to no deformation.
Material erosion – It is the gradual wearing away or removal of material from a surface by the action of external forces. In geology, this frequently involves natural agents like water, wind, ice, or gravity detaching and transporting soil, rock, and sediment. In engineering, erosion refers to the physical damage caused by impacts from particles in a fluid, high-speed fluid flow, or other mechanical processes, leading to wear and degradation of components.
Material extrusion – It is an additive manufacturing (3D printing) process which builds objects by selectively depositing a heated material layer by layer through a nozzle. This material, typically a thermoplastic polymer in filament form, is forced through a heated nozzle that melts and deposits it onto a build platform, where it cools and solidifies to form the part. This technique is also known by names such as fused deposition modeling (FDM).
Material flow diagram – It is also known as material flow chart. It is used to visualize the use of materials. e.g. along a supply chain. It is used to show material and mass flows in a visually appealing way. Hence, it can show e.g., the distribution of goods or the consumption of resources within a production system. Also, it is applicable for holistic material flow analyses. It can cover a large number of areas such as (i) material flow analysis and management, (ii) supply chain management, (iii) plant planning, (iv) process engineering, and (v) logistics. Several times, it is visualized by so called Sankey diagram where flow widths proportional to the flow quantity. Material flow diagram provides a lot of benefits for the visualization of material usages.
Material flow optimization – It is the seamless movement of materials along the conveyor system, needing continuous evaluations for potential obstructions, misalignments, and efficient throughput.
Material flow rate – It is the quantity of a material which moves through a system or conduit over a period of time. This can be measured as a volume flow rate (e.g., cubic metre per minute) or a mass flow rate (e.g., kilograms per minute).
Material grade – It is a classification for a substance based on its specific chemical, physical, and mechanical properties, determined by its composition, purity, and how it was processed. It provides a standardized way to identify a material and assess its suitability for a particular application, with different grades existing for different materials like steel, plastics, or chemicals.
Material handling – It is a system designed for the storage and retrieval of materials in manufacturing and distribution.
Material handling procedure – It consists of the overall process of moving, controlling, and manipulating materials on the conveyor system. Continuous evaluations are necessary for efficiency, safety, and optimal workflow.
Material handling system – It utilizes manual, semi-automated, and automated equipment to assist the movement and storage of materials within the system. Material handling system equipments are grouped into four main categories named storage and handling equipments, bulk material handling equipments, mobile equipments and industrial trucks, and engineered systems.
Material hardness – It is the property of the material which enables it to resist plastic deformation, usually by penetration or by indentation. The term of hardness is also referred to stiffness or temper, or to resistance to bending, scratching, abrasion, or cutting. It is the property of a material, which gives it the ability to resist being permanently, deformed when a load is applied. The higher is the hardness of the material, the higher is the resistance it has to deformation.
Materiality – It needs that a public report contains all the relevant information which investors and their professional advisers reasonably need, and reasonably expect to find in the report, for the purpose of making a reasoned and balanced judgement regarding the Exploration results, Mineral resources or Ore reserves being reported. Where relevant information is not supplied an explanation is to be provided to justify its exclusion.
Material loss – It is the difference between the theoretical quantity of a material and the actual quantity used, occurring through processes like handling, storage, or manufacturing. These losses can be normal (unavoidable, like evaporation) or abnormal (because of the inefficiency, like theft) and take the form of waste, scrap, spoilage, or defects
Material models – Material models quantify physical material properties, that is, the ability of the material to respond to physical influences.
Material modelling environment – It contains multi-disciplinary sub-models integrated into the life cycle system boundary, consisting of materials processing and manufacturing.
Material of construction – It refers to the specific substances and products used to build and assemble a structure or piece of equipment. This term has a broad meaning, covering everything from natural materials like wood and stone to manufactured items like steel, concrete, plastic, and glass. The choice of material is based on factors like durability, strength, intended use, cost, and local regulations.
Material optimization – It is the process of systematically selecting and designing materials to achieve the best possible performance under specific constraints, such as cost, weight, or efficiency. It involves using mathematical models and computational methods to find the ideal material properties and distribution to meet design objectives, like maximizing strength while minimizing material usage and waste.
Material parameter – It is a physical property or coefficient which describes a material’s behaviour, such as its density, elasticity, or thermal conductivity. These parameters are necessary for modeling how a material performs under different conditions and are determined through experimental testing. By defining and using these parameters in constitutive equations, engineers can accurately predict a material’s response and ensure product safety and efficiency.
Material performance – It describes how well a material behaves and functions under specific, real-world conditions like stress, temperature, and environmental exposure. It is a critical aspect of material selection and product design, ensuring that a material can meet performance criteria and operate reliably over its expected lifetime. Material performance is determined by a material’s properties, which are directly influenced by its atomic structure and processing history.
Material property – It is an intensive property of a material, i.e., a physical property or chemical property which does not depend on the quantity of the material. These quantitative properties can be used as a metric by which the benefits of one material against another can be compared, hence helping in materials selection.
Material recovery facility – It is also known as a materials reclamation or recycling facility. It is a specialized waste sorting and recycling system which receives, separates, and prepares recyclable materials for marketing to end-user manufacturers.
Material removal rate – It is the quantity of material removed per time unit (normally per minute) when performing machining operations such as using a lathe or milling machine. The more material removed per minute, the higher the material removal rate. The material removal rate is a single number that enables an operator to do this. It is a direct indicator of how efficiently the operator is cutting, and how profitable the operator is. Material removal rate is the volume of material removed per minute. The higher are cutting parameters, the higher is the material removal rate. In grinding, it is the volume of material removed in a unit of time. Material removal rate = work speed × depth of cut × width of cut.
Material resource planning (MRP) system – It is a production planning, scheduling, and inventory system used to manage manufacturing processes. Majority of the material requirements planning systems are software-based, but it is possible to conduct material requirements planning manually as well. A material requirements planning system is intended to simultaneously meet three objectives namely (i) ensure raw materials are available for production and products are available for delivery to customers, (ii) maintain the lowest possible material and product levels in store, and (iii) plan manufacturing activities, delivery schedules and purchasing activities.
Material safety data sheet (MSDS) – It is a form which contains detailed information about the possible safety and health hazards of a product and how to safely store, use, and handle the product. In several countries, suppliers are required to provide material safety data sheets for all hazardous materials as a condition of sale.
Materials degradation – It is the gradual decline in a material’s properties and performance because of the physical, chemical, or biological changes, frequently caused by environmental exposure or operational stress. This deterioration can lead to a loss of strength, changes in a material’s physical properties, and a shorter lifespan for products and systems. Common causes include wear, corrosion, heat, moisture, UV (ultra-violet) radiation, and biological attack.
Material selection – It is a step in the process of designing any physical object. In the context of product design, the main goal of material selection is to minimize cost while meeting product performance goals. Systematic selection of the best material for a given application begins with properties and costs of candidate materials. Material selection is frequently benefited by the use of material index or performance index relevant to the desired material properties.
Materials engineering – It is an engineering discipline of finding uses for materials in different fields and industries.
Materials management – It involves anticipating and planning the materials needed for a production process. The key objectives are to get the best value for purchased materials and ensure supplies are available when and where needed. The initial stages of this process are vital and, if done properly, provide opportunities for cost savings.
Material specification – It is a document which details the properties, characteristics, and requirements of materials used in manufacturing, construction, or product design. It ensures that the materials used meet specific quality, performance, and safety standards. These specifications frequently include information on dimensions, chemical composition, mechanical properties, and compliance with relevant regulations.
Materials performance index – It is a combination of materials properties formulated in such a way that the largest value of the index designates the best material for the application.
Materials processing – It consists of the series of steps or ‘unit operations’ used in the manufacture of raw-materials into finished goods. The operations involve a succession of industrial processes with different mechanical or chemical procedures, normally produced in large quantities or batches.
Materials recovery – It is the process of extracting usable materials from solid waste, which can then be reused, recycled, or composted. This process is a key part of solid waste management, involving the collection, sorting, and processing of materials from the waste stream to reduce the need for new resources and decrease the volume of waste sent to landfills. It often occurs at a materials recovery facility, which uses manual or mechanical means to separate components for resale as raw materials.
Materials science – It is the study of materials, their properties and their applications. It is an inter-disciplinary field of studying and discovering materials.
Materials testing laboratory – It is a specialized facility which uses a range of instruments and techniques to evaluate a material’s mechanical, physical, chemical, and thermal properties. These laboratories are important for quality control and for ensuring materials are safe, durable, and perform as intended in different applications, such as construction and manufacturing.
Material stock – It is the quantity of raw materials which are readily available for manufacturing.
Material substitution – It is a class of material selection problem where a design already exists and the task is to replace the existing material with a more suitable one.
Material surface engineering – It is the field of engineering which modifies the surface properties of a material to improve its performance, functionality, or durability, without changing its bulk properties. This is achieved through techniques like coatings, surface treatments, and ion implantation to improve resistance to wear, corrosion, and fatigue, or to introduce new functionalities.
Material transformation – It is the process of changing a material’s physical, chemical, or structural properties to create new materials or products. This can involve altering its form, composition, or characteristics through methods like heating, cooling, mixing, or applying energy, which are crucial for achieving desired properties like strength, toughness, and stability. Examples include phase transformations in metals or the grinding and mixing of source materials for manufacturing.
Material utilization – It is the percentage of the material processed that ends up in the product. A high material utilization means high product yield and near-net shape processing.
Mathematical model – It is an abstract description of a concrete system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used in process control and engineering disciplines.
Mat foundation – It is also called raft foundation. It is a large, continuous concrete slab which extends under an entire structure to support it. It is used when the soil has low bearing capacity, the building has high loads, or columns are too close together for individual footings. By spreading the total load over a large area, the mat foundation minimizes stress on the soil and reduces the risk of differential settlement, ensuring the structure’s stability.
Mating parts – Mating parts refer to two or more components which are designed to fit together, frequently with a specific type of connection or fit, to form a larger assembly. These parts have features or surfaces which are designed to interact and create a functional connection, whether it is a simple sliding fit or a more complex interference fit.
Mating ring – It is a rigid, stationary component of a mechanical seal assembly which provides a hard, non-flexible surface for the primary (or rotating) seal ring to run against, creating a seal to prevent leakage. It is designed to remain stationary and minimizes distortion and heat transfer while forming a precise, perpendicular plane for the primary ring. Mating rings are important for maintaining the integrity of fluid systems, and their design and material selection are critical for performance.
Mating surfaces – Mating surfaces refer to the areas on two or more parts which come into contact with each other when they are joined together. These surfaces are crucial for ensuring proper alignment, connection, and functionality of the assembled parts.
Matmor process – It is an iron making process which is based on lignite coal. It is a process with a design consisting of a simple, low cost, low emission, and Matmor retort using cheaper, alternative raw materials. This technology comprises two exclusive features namely (i) it uses lignite coal as a reductant and heat source which is not claimed as of now by any other technology, and (ii) it includes in its plant design, a vertical shaft furnace which works with the natural chemistry of the lignite coal. The process is based upon the removal of moisture by Coldry technology and the harnessing of the natural chemistry of the lignite coal through a process and a vertical retort furnace whose design and process chemistry is different to those of a blast furnace. The process chemistry of the Matmor process utilizes hydrogen as a reducing gas, enabling lower operating temperatures and shorter process times than countered in the iron making by blast furnace.
Matrix – It is the continuous or principal phase in which another constituent is dispersed. It is also the principal element or elements in a sample. Ion composites, matrix is the essentially homogeneous material in which the fibre system or reinforcing particles of a composite are embedded. Both thermo-plastic and thermo-set resins can be used, as well as metals, ceramics, and glasses.
Matrix-assisted pulsed laser evaporation (MAPLE) – It is a thin film deposition technique used in engineering to transfer delicate organic materials onto a substrate without damaging them. In this process, the material to be deposited is dissolved in a volatile solvent at a low concentration, and this solution is frozen to form a solid target. A laser pulse ablates the surface of this target, with the energy being preferentially absorbed by the solvent, which evaporates and carries the intact material to a substrate.
Matrix chart – It is a type of flow chart in which the activities in a process are shown under the department carrying it out.
Matrix degradation – It is the deterioration of a material’s matrix, which can be caused by mechanical stress, heat, or chemical reactions like oxidation or hydrolysis. This process leads to a decrease in the matrix’s molecular weight and / or cross-linking, resulting in a reduction of its structural properties, such as strength and stiffness. It is a critical failure mode in composite materials, affecting their long-term durability and performance.
Matrix densification – It refers to the process of reducing voids and increasing the density within a material’s matrix, which can be achieved through methods like chemical treatments (e.g., concrete hardeners) or physical processes like mechanical compression or thermal sintering. This process is used to improve material properties such as strength, durability, and hardness.
Matrix failure – It refers to the failure of the matrix material in a composite, which frequently involves the formation of cracks that can propagate, leading to delamination and a compromised structural integrity. This type of failure is caused by stresses exceeding the matrix’s strength and can be initiated during manufacturing or loading, ultimately contributing to the composite’s overall failure.
Matrix fibre composite – It is a composite material engineered by embedding high-strength fibres (dispersed phase) within a continuous matrix material to create a material with properties superior to either component alone. The fibres provide strength and stiffness, while the matrix binds the fibres together, distributes stress, and protects them from damage. The overall properties, such as strength, stiffness, and flexibility, can be tailored by varying the type, orientation, and concentration of the fibres.
Matrix isolation – It is a technique for maintaining molecules at low temperature for spectroscopic study. This method is particularly well suited for preserving reactive species in a solid, inert environment.
Matrix materials – These are essential components used in composite materials, acting as a binder which holds reinforcement fibres together to improve structural integrity. Normally used matrix materials include polymers, metals, and ceramics, each offering unique properties like durability, flexibility, and thermal resistance. Understanding of the role and types of matrix materials helps optimize composite material performance for various applications across industries.
Matrix metal – It is the continuous phase of a polyphase alloy or mechanical mixture. It is the physically continuous metallic constituent in which separate particles of another constituent are embedded.
Matrix structural analysis – It is a systematic procedure for the analysis and design of structures, involving the modeling of structural elements, foundation, and external actions, followed by numerical simulation to evaluate stress resultants and deformations. It encompasses iterative design modifications to achieve optimal structural performance while considering safety and functionality.
Matte – It is an intermediate product of smelting. It is an impure metallic sulphide mixture made by melting a roasted sulphide ore, such as an ore of copper, lead, or nickel. Matte is to be refined further to get pure metal. In galvanizing, matte is dull, lacking or deprived of shine. Matte gray galvanized appearance can result from steel chemistry or can be intentionally induced when the use of the galvanized steel defines reflectivity limits.
Matte finish – It is a dull texture produced by rolling sheet or strip between rolls which have been roughened by blasting. It is a dull finish characteristic of some electrodeposits, such as cadmium or tin.
Matte grade – It normally refers to the percentage of copper (mass % Cu) in the molten sulphide mixture, known as copper matte, created during the smelting of copper ore. This grade typically ranges from 45 % to 75 % copper and is a key metric in metallurgical processes, as it influences the efficiency of smelting and the activity of copper sulphides. It can also be defined for other metals like nickel, representing the percentage of a specific metal in the matte.
Matter – It is a substance which has mass and takes up space by having volume.
Mat top conveyor – It is a conveyor featuring a flat, solid surface, which is normally used for transporting larger items. Periodic checks are necessary for wear, alignment, and smooth material flow.
Maul – It is a heavy frequently wooden-headed hammer used especially for driving wedges. It is also a tool like a sledgehammer with one wedge-shaped end that is used to split wood.
Maximum – The maximum is the highest value in a numerical variable. In the variable with the values 12, 15, 11, 18, 13, 14, 18 then 18 is the maximum value.
Maximum absolute error – It is the largest possible difference between a measured value and the true value, representing the upper limit of uncertainty in a measurement. It is calculated as the absolute value of the difference between the measured and true value, and is expressed in the same units as the measurement. For example, if a ruler has millimeter markings, the maximum absolute error for a measurement is 0.5 millimeters.
Maximum allowable concentration – It is the highest permissible level of a substance (like a pollutant, chemical, or contaminant) in a specific environment, such as the air, water, or a workplace, which is not expected to cause substantial harm to human health or the environment. It is a regulatory limit set by authorities and is used to assess environmental quality and ensure public and worker safety.
Maximum allowable operating pressure (MAOP) – It is the operating pressure in the pipes which is determined in accordance with the piping codes, and pipe transportation regulations etc.
Maximum allowable outage -It is the maximum period of time that a system, process, or service can be unavailable or disrupted before its failure causes unacceptable damage to an organization. It is also known by other names, such as maximum acceptable outage, maximum tolerable period of disruption (MTPD), and maximum tolerable downtime (MTD).
Maximum allowable stem torque (MAST) – It is a torque value published by the valve manufacturer of the maximum torque which can be applied to a valve stem before permanent deformation can occur. The actuator maximum torque is not to exceed this figure.
Maximum allowable stress – It is the highest level of stress a material can safely withstand without failing, ensuring a safety margin against damage or collapse. It is calculated by taking a material’s failure stress (such as its yield or tensile strength) and dividing it by a safety factor, which is set by industry codes and engineering standards. This limit is a crucial design parameter that helps prevent a structure from yielding, fracturing, or breaking under load.
Maximum allowable working pressure (MAWP) – It is the maximum gauge pressure permissible in a completed boiler. The maximum allowable working pressure of the completed boiler is to be less than or equal to the lowest design pressure determined for any of its parts. This pressure is based upon either proof tests or calculations for every pressure part of the boiler using nominal thickness exclusive of allowances for corrosion and thickness needed for loadings other than pressure. It is the basis for the pressure setting of the pressure relieving devices protecting the boiler.
Maximum bending moment – It is the largest value of bending moment at any point along a structural element, occurring where the shear force changes sign from positive to negative or zero. It represents the point of maximum stress and curvature in the structure, which is a critical factor in engineering design to ensure stability.
Maximum bending stress – It is the highest stress which occurs at the outermost fibres of a material when it is subjected to a bending moment. This stress varies linearly across the cross-section, being zero at the neutral axis and reaching its peak at the points farthest from it. It is a critical value for structural design to ensure a component can withstand applied loads without failing.
Maximum contact pressure – It is the highest intensity of force per unit area exerted at the interface where two surfaces touch. It represents the peak stress at the contact point, which is a critical factor in designing and analyzing mechanical systems and structures. The distribution of this pressure is complex and depends on the materials’ properties, the applied force, and the geometry of the contact surfaces.
Maximum contaminant levels – These are the levels as per the standards which are set for drinking water quality. A maximum contaminant level is the legal threshold limit on the quantity of a substance which is allowed in public water systems. The limit is usually expressed as a concentration in milligrams or micrograms per litre of water.
Maximum continuous load – It is the maximum load which can be maintained for a specified period.
Maximum cooling rate – It is the highest rate at which a material can be cooled, It is the highest possible decrease in temperature per unit of time, which depends on factors like the material, instrument, and cooling medium. It is frequently expressed in units of degrees Celsius per minute or Kelvin per second and is important for controlling a material’s micro-structure and properties.
Maximum daily limit (MDL) – It is the total maximum daily load. It is the absolute maximum allowable load or concentration of a substance in a facility’s effluent. This limit can be based on water quality constraints, sector-specific technology limits, or case-specific technology considerations. The value is typically calculated based on the 99th percentile of existing or required performance.
Maximum design temperature – It is the highest temperature at which a component, like a pressure vessel or HVAC (heating, ventilation, and air conditioning) system, is engineered to operate safely and reliably, frequently set at a margin above the expected maximum operating temperature to account for potential surges and other factors. This temperature is critical for selecting materials and determining needed component thickness and is specified in design codes and standards to ensure safety and durability under specified conditions.
Maximum direct stress – It is the highest stress within a material caused by a load acting perpendicular to its cross-sectional area. It can be a tensile or compressive stress and occurs at the point where the stress is most concentrated. This can happen in two main scenarios: when a material is subjected to two mutually perpendicular stresses, or when an eccentric load creates both direct and bending stresses, which add up to a maximum on one side of the component.
Maximum dilatation – Maximum dilatation test measures the expanding and contracting characteristics of the coal. The test is carried out in Audibert-Arnu dilatometer. Finely crushed coal is compressed into a pencil, which is heated slowly and as the coal passes through its plastic range, the pencil initially gets shorter (contracts) and then gets longer (expands). Measurements taken are the ‘maximum contraction’ and ‘maximum dilation (expansion)’, both expressed as a percentage of initial pencil length, such that maximum contraction is always positive, and the maximum dilation is positive when the pencil increases in length from the initial length and negative when the pencil decreases in length. Temperature of initial softening (first indication of the pencil contraction), and maximum dilation is also recorded. Results from this test are very sensitive to oxidation of the coal being tested.
Maximum dry density – It is the highest density a soil can achieve when compacted, which occurs at an ideal moisture content known as the optimum moisture content (OMC). This value is determined through laboratory tests, such as the standard Proctor or modified Proctor compaction tests, and is important for ensuring the structural integrity of projects like roads and buildings.
Maximum erosion rate – It is the maximum instantaneous erosion rate in a test which shows such a maximum followed by decreasing erosion rates. Occurrence of such a maximum is typical of several cavitation and liquid impingement tests. In some examples, it occurs as an instantaneous maximum, in others it occurs as a steady-state maximum which persists for some time.
Maximum flow rate – It is the highest rate at which a fluid can be moved through a system at a specific time. This value varies depending on the context, but it normally refers to the peak capacity for flow in a pump, pipe, river, or even an electrical system. It is an important metric for applications like designing dams, selecting pumps, or managing water resources.
Maximum flux density – It is the highest value of magnetic flux per unit area which a magnetic material can handle before it becomes saturated. In a transformer, this is the peak magnetic flux density in the core, measured in tesla (T), and it is a critical design parameter that influences the transformer’s efficiency and performance.
Maximum heat flux – It is the highest rate of heat transfer per unit area which can occur in a system, particularly in a boiling process. It represents the peak heat transfer capacity before a sudden and dangerous drop in heat transfer efficiency, which can lead to overheating or system failure. This maximum value is frequently called critical heat flux (CHF), and its prediction is critical for safety in industrial applications like power boilers and reactors.
Maximum instantaneous demand – It is the sudden load demand on a boiler beyond which an unbalanced condition can be established in the boiler’s internal flow pattern and / or surface release conditions.
Maximum likelihood estimation (MLE) – It is a method of estimating the parameters of an assumed probability distribution, given some observed data. This is achieved by maximizing a likelihood function so that, under the assumed statistical model, the observed data is most probable. The point in the parameter space which maximizes the likelihood function is called the maximum likelihood estimate. The logic of maximum likelihood is both intuitive and flexible, and as such the method has become a dominant means of statistical inference. Maximum likelihood estimation is a means of estimating the coefficients of a statistical model which relies on finding the coefficient values that maximize the likelihood function for the collection of study endpoints in the sample.
Maximum likelihood method – It is a method of parameter estimation in which a parameter is estimated by the value of the parameter which maximizes the likelihood function. In other words, the maximum likelihood estimator is the value of theta which maximizes the probability of the observed sample. The method can also be used for the simultaneous estimation of several parameters, such as regression parameters. Estimates obtained using this method are called maximum likelihood estimates.
Maximum load (Pmax) – It is the load which is having the highest algebraic value in the load cycle. Tensile loads are considered positive and compressive loads negative. The term is also used to determine the strength of a structural member i.e., the load which can be borne before failure is apparent.
Maximum nominal stress – It normally refers to the ultimate tensile strength, which is the maximum stress a material can withstand before it starts to deform permanently or fracture. Nominal stress is calculated by dividing the applied force by the material’s original cross-sectional area, before any deformation occurs. Hence, the maximum nominal stress is the highest value this ratio can reach for a specific material under tension, before it fails.
Maximum operating design range – It is a combination of the highest and lowest conditions a process or piece of equipment is designed to handle safely, encompassing both operational limits and engineering calculations.
Maximum operating pressure – It is the highest pressure a component or system can safely withstand during its normal, everyday operation without risk of failure. It is a critical design parameter which ensures safety by establishing the upper limit for pressure under typical conditions and is frequently determined by factors like the design pressure, hydrostatic test pressure, or flange rating.
Maximum operating temperature – It is the highest temperature at which a system, device, or material can function correctly without degradation or failure, and is defined as a limit for normal conditions. It is a critical parameter for designing and selecting products, ensuring durability, and preventing damage. Exceeding this temperature, even for short durations, can lead to reduced performance or failure.
Maximum output power – It is the highest quantity of power a system or device can generate or transmit under normal operating conditions before any limitations are imposed. It represents the peak performance level, which can vary depending on the context, such as an engine, a laser, or a communication terminal. This value is crucial for determining a system’s capabilities.
Maximum pore size – It is the maximum pore opening of a porous material, such as a filter, through which no large particle passes.
Maximum prospective short-circuit current – It is the calculated value of current which can flow if a short circuit occurred. It is a parameter for selection of circuit protection devices.
Maximum rate period – In cavitation and liquid impingement erosion, it is a stage following the acceleration period, during which the erosion rate remains constant (or nearly so) at its maximum value.
Maximum shear force – It is the largest internal shear force a structural element, such as a beam, experiences along its length under a given set of loads. It is a critical value for engineers, as it represents the point of highest shear stress and is used to ensure the structural integrity and safety of the element by designing it to withstand these forces without failure. To find the maximum shear force, one is to analyze the loading conditions and draw a shear force diagram to identify the section experiencing the greatest shear force.
Maximum shear strain – It is the peak value of shear deformation in a material, which occurs when the material’s shape is considerably distorted by forces acting parallel to its surface. It can be defined as the tangent of the angle of shear, or the ratio of the maximum displacement (delta ‘x’) to the perpendicular length (L) of the material (Tan A = delta ‘x’/L). In engineering, this concept is used to understand a material’s limit and is important for designing structures which can withstand shearing forces.
Maximum shear stress – It is the highest intensity of shear stress occurring at a specific point in a material, which is important for structural and mechanical design. It is mathematically defined as half the difference between the maximum and minimum principal stresses. This stress occurs on a plane which is oriented at 45-degree to the principal planes, where the normal shear stress is zero.
Maximum strength – It is the maximum stress (tensile, compressive, or shear) which a material can sustain without fracture. It is determined by dividing maximum load by the original cross-sectional area of the sample. It is also known as the ultimate strength.
Maximum stress (Smax) – It is the stress having the highest algebraic value in the stress cycle, tensile stress being considered positive and compressive stress negative. The nominal stress is used very frequently.
Maximum stress intensity factor (Kmax) – It is the maximum value of the stress-intensity factor in a fatigue cycle.
Maximum surface temperature – It is the highest temperature which a hazardous area apparatus can reach under fault conditions, based on an ambient temperature of 40 deg C or as specified for different environments.
Maximum temperature – It is the highest temperature reached in a given system or process.
Maximum tensile stress – It is also known as ultimate tensile strength. It is the highest stress a material can withstand while being stretched or pulled before it breaks or fractures. It is calculated by dividing the maximum tensile force a material can endure by its original cross-sectional area.
Maximum tension – It is the highest tension occurring in any portion of the conveyor belt under operating conditions.
Maximum tolerable downtime – It is the longest period a system, service, or operational function can be down without causing irreparable harm or unacceptable damage to an organization. This engineering concept is a key component of operational continuity and disaster recovery planning, and it is always longer than the recovery time objective, which is the target time for recovery
Maximum tolerable failure rate – It is the highest acceptable rate of failure for a system, calculated by factoring in the maximum tolerable risk and other external factors which limit the severity of an event. It represents a quantifiable risk threshold and is used to establish the minimum reliability needed for a system or function to meet its safety and operational goals. The acceptable failure rate is not a single universal number but varies based on context, with factors like the cost of failure, customer expectations, and the potential for user harm influencing the specific threshold.
Maximum tolerable risk – It is the highest level of risk which is considered acceptable in a specific context, balancing risks against benefits and considering societal, economic, legal, and technical factors. It is the threshold above which a risk is no longer considered bearable or acceptable, and it is to be reduced further. This differs from ‘acceptable risk’, which is frequently used interchangeably but ‘tolerable risk’ is preferred in functional safety standards.
Maximum working pressure (MWP) – It is the maximum pressure at which a process / piping system / valve can be operated.
Maxwell model – It is a simple mathematical model used to describe the viscoelastic properties of materials, representing them as a linear spring and a linear viscous dashpot connected in series. It demonstrates that a material can behave elastically (like a spring) under quick deformation but also show viscous flow (like a dashpot) over longer periods. This model is useful for explaining phenomena like stress relaxation and creep in viscoelastic fluids and solids.
Maxwell’s equations – These are the fundamental relations between electric and magnetic fields, expressed in concise mathematical form.
MC carbides – These are a type of metal carbide (MC), specifically those found in nickel-based superalloys, characterized by an sodium chloride like face-centered cubic (FCC) structure. They are normally coarse and known for their stability at high temperatures, contributing to the creep resistance of these alloys. In the context of superalloys, ‘M, in MC typically represents transition metals like titanium, chromium, niobium, hafnium and tantalum.
M6C carbides – These are a type of complex carbide found in several metallic alloys, particularly steels and superalloys. They are characterized by a face-centered cubic (FCC) crystal structure and are typically rich in molybdenum and tungsten, but can also contain chromium and other elements. M6C carbides frequently form during solidification or heat treatment processes and can considerably influence the mechanical properties of the material.
McKelvey box – It is also called McKelvey diagram. It is a visual tool used to classify natural resources (like minerals or fossil fuels) based on their geological certainty of existence and economic feasibility of recovery, helping to understand the uncertainty and risk associated with their availability.
McLeod gauge – It is a high-precision vacuum gauge which measures very low pressures by compressing a gas sample with mercury. It operates on Boyle’s law (P1V1 = P2V2), where an unknown pressure (P1) is determined by trapping a known volume of gas (V1), compressing it to a smaller volume (V2) with mercury, and then measuring the final pressure (P2). This is a manual and complex instrument, frequently used as a reference standard for calibrating other gauges, though it has largely been replaced by electronic gauges for continuous readings.
M-commerce – It is also called mobile commerce. It refers to the buying and selling of goods and services using mobile devices like smartphones and tablets. It encompasses all commercial transactions conducted through mobile technology, including mobile payments, in-app purchases, and other mobile-based transactions. Essentially, it is e-commerce conducted on mobile devices.
McQuaid-Ehn grain size – It is the austenitic grain size developed in steels by carburizing at 927 deg C followed by slow cooling. Eight standard McQuaid-Ehn grain sizes rate the structure, from number 8 which is the finest size, to number 1 which is the coarsest size. The use of standardized methods for determining grain size is desired.
McQuaid-Ehn test – It is a method for determining the average grain size of steel by carburizing a sample, which causes the prior austenite grain boundaries to become visible under a microscope. A sample is heated in a carburizing atmosphere, and the carbon segregates at the grain boundaries, forming carbides which outline the grains after cooling and polishing. The resulting etched surface is then compared to a standard chart with sizes numbered from 1 (very coarse) to 8 (very fine).
MC section – It is a channel section which cannot be classified as a ‘C’ section.
Meallographic structure – It is the nature, distribution, and quantities of the metallographic constituents in a metal.
Mean – It is an important statistic tool which measures the central tendency of a set of data. It is a measure of the ‘middle’, sometimes called the ‘average’. It is that value of a variate such that the sum of deviations from it is zero, and hence it is the sum of a set of values divided by their number.
Mean absolute error (MAE) – It is a metric which quantifies the average magnitude of errors in a set of predictions, without considering their direction. In simpler terms, it is the average of the absolute differences between predicted and actual values. A lower mean absolute error indicates better predictive performance.
Mean cell residence time (MCRT) – It is also known as solids retention time (SRT). It is the average amount of time that micro-organisms (or solids) spend in a waste-water treatment system. It is a key parameter in activated sludge processes, helping assess treatment efficiency. Mean cell residence time is calculated by dividing the total mass of solids in the system by the mass of solids wasted (removed) per day.
Mean coefficient of linear thermal expansion – It is the ratio of the change in length to the original length at a reference temperature, ‘T0’, per degree of temperature change, where ‘T0’ is normally room temperature. If ‘L0’ is the length at ‘T0’ and alpha (a) is the mean coefficient of linear thermal expansion, the length at temperature ‘T1’ (Lt), is given by the equation Lt = L0[1 + a(T1-T0)].
Mean deviation – The mean deviation is a measure of spread. The mean deviation is an average (mean) difference from the mean. The value it gives is similar, but slightly smaller than the standard deviation. Although it is intuitively simpler than the standard deviation it is used less. The reason is largely since the standard deviation is used in inference, because the population standard deviation is one of the parameters of the normal distribution.
Mean diameter – It is the average of two measurements of the diameter at right angles to each other.
Mean duration rate – It is the total number of days lost divided by the total number of accidents during the period.
Mean effective pressure (MEP) – It is a quantity relating to the operation of a reciprocating engine and is a measure of an engine’s capacity to do work which is independent of engine displacement. In spite ot having the dimension of pressure, mean effective pressure cannot be measured. When quoted as an indicated mean effective pressure (IMEP), it can be thought of as the average pressure acting on a piston during the different portions of its cycle. When friction losses are subtracted from the indicated mean effective pressure, the result is the brake mean effective pressure (BMEP).
Mean flow pore size – It is the pore diameter at which 50 % of the total gas flow passes through pores larger than that size. It is calculated by comparing the flow rate of a dry sample with the flow rate of a wet sample at a specific pressure point. This is a measure of a material’s pore structure, particularly useful in capillary flow porometry (CFP).
Mean free path – It is the average distance over which a moving particle (such as an atom, a molecule, or a photon) travels before substantially changing its direction or energy (or, in a specific context, other properties), typically as a result of one or more successive collisions with other particles.
Mean maximum reflectance, MMR – It is also known as vitrinite reflectance- It is used to determine the coal rank, is measurement by the percentage of light reflected off the vitrinite maceral at 500x magnification in oil immersion. The mean maximum reflectance values for metallurgical coal 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 %.
Mean of a variable – It is the arithmetic average of the variable’s values.
Mean sea level (MSL) – It is the average height of the ocean’s surface over a long period, used as a reference point for measuring elevation and altitude. It’s essentially the average level of the sea, accounting for tidal variations and other short-term fluctuations. It is normally defined as the average relative sea level over a period, such as a month or a year, long enough to average out transients such as waves.
Mean shear stress – It is the average force acting parallel to a surface, divided by the area of that surface (S = F/A). It represents the internal resistance of a material to deformation when layers of the material slide against each other, and it is calculated by dividing the total shear force by the cross-sectional area.
Means of escape – It is the structural means whereby a safe route is provided for persons to travel unaided from any point in a building to a place of safety.
Mean square error (MSE) – For unbiased estimators, the mean square error is an estimate of the population variance. For biased estimators, the mean squared deviation of an estimator from the true value is equal to the variance plus the squared bias. The square root of the mean square error is referred to as the root mean square error.
Mean stress (Sm) – It is the algebraic average of the maximum and minimum stresses in one cycle, i.e., Sm = (Smax + Smin)/2. It is also referred to as steady component of stress.
Mean time between failures (MTBF) – It is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. It is a maintenance metric (opens in new tab) that measures the average amount of time a non-repairable asset operates before it fails.
Mean time to failure (MTTF) – It is the average life to failure for the equipment failure mode. Hence, it represents the point at which the areas under the failure distribution curve are equal above and below the point. Determining the mean time to failure, hence, depend on the type of failure distribution used to model the failure mode. Mean time to failure data are helpful in determining when to perform certain types of maintenance tasks. For example, if the appropriate maintenance strategy is to rebuild an equipment item, the mean time to failure data can be used to help set the rebuilding task interval. If the mean time to failure is represented by a normal distribution and the interval is set at the mean time to failure, then one can assume that there is a 50 % chance of the item failing before it is rebuilt. If the interval is set less than the mean time to failure, then the probability of the item failing before being rebuilt is less than 50 %. If the interval is more than the mean time to failure, then the probability is more than 50 %. The increase or decrease in probability as the interval is moved before or after the mean time to failure depends on the standard deviation of the distribution.
Mean time to recovery (MTTR) – It is the average time it takes an organization to fully restore a system after a failure. This metric includes the entire outage period, from the moment a failure occurs until the system is operational again, encompassing detection, diagnosis, and repair. Organizations use mean time to recovery to measure incident management efficiency, assess system reliability, and identify areas for improvement.
Mean wall thickness – For a tube this is the sum of four wall thickness measurements, made at 90-degree intervals around the diameter, divided by four.
Measurable property – It is an observable characteristic of a system or object which can be quantified, or assigned a numerical value, through measurement. These properties describe the state of a physical system and can be used to track changes, such as the mass, volume, pressure, or temperature of a gas.
Measurable quantity – It is an attribute of a phenomenon, body, or substance which can be distinguished qualitatively and determined quantitatively. This means it can be measured or expressed in specific terms, such as size, quantity, duration, or mass, frequently with a numerical magnitude and a unit. Examples include length, mass, time, and velocity.
Measurand – It is a particular quantity subject to measurement. For example, vapour pressure of a given sample of water at 20 deg C. The specification of a measurand can require statements about quantities such as time, temperature, and pressure.
Measured area of the rectified signal envelope (MARSE) – It is sometimes referred to as energy counts. It is the measure of the area under the envelope of the rectified linear voltage time signal from the transducer. This can be thought of as the relative signal amplitude and is useful since the energy of the acoustic emission can be determined. Measured area of the rectified signal envelope is also sensitive to the duration and amplitude of the signal, but does not use counts or user defined thresholds and operating frequencies. It is regularly used in the measurements of acoustic emissions.
Measured Mineral resource – A ‘Measured Mineral resource’ is that part of a Mineral resource for which quantity, grade (or quality), densities, shape, and physical characteristics are estimated with confidence sufficient to allow the application of Modifying factors to support detailed mining planning and final evaluation of the economic viability of the deposit. Geological evidence is derived from detailed and reliable exploration, sampling, and testing gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes, and is sufficient to confirm geological and grade (or quality) continuity between points of observation where data and samples are gathered. A Measured Mineral resource has a higher level of confidence than that applying to either an Indicated Mineral resource or an Inferred Mineral resource. It can be converted to a Proved Ore reserve or under certain circumstances to a Probable Ore reserve.
Measurement – Measurement is the process by which one can convert physical parameters to meaningful numbers. It is the process of determining the quantity, degree, capacity by comparison (direct or indirect) with the accepted standards of the system units being used. It is a process of comparing an unknown quantity with an accepted standard quantity. The measuring process is one in which the property of an object or system under consideration is compared to an accepted standard unit, a standard defined for that particular property. A measuring instrument can determine the magnitude or value of the quantity to be measured. The measuring quantity can be voltage, current, power, and energy etc. Measurement can be done by direct method of measurement or indirect method of measurement. Measurement of process parameters is an important aspect for the control of a process. Examples of the process parameters which are to be measured for control are pressure, temperature, flow, mass, length, and level etc.
Measurement condition – It refers to the specific circumstances and factors under which a measurement is taken, which include things like temperature, pressure, light, and time, and the procedure used. These conditions are important since they can affect the accuracy and reliability of the results, and are documented to ensure that results are consistent, repeatable, and comparable across different tests.
Measurement cycle – It is a defined period of time during which a specific task or process is measured, from its start to its completion. The term can also refer to the sequence of operations involved in taking a single measurement, such as applying a current and measuring a response in an electrical circuit. The concept of a ‘cycle’ is central, representing a complete unit of work or observation.
Measurement error – It is the difference between the true value of a quantity and its measured value, indicating the inaccuracy or uncertainty of a measurement. This difference can be because of the random factors, like slight variations in an experiment, or systematic factors, like a mis-calibrated instrument.
Measurement inaccuracy – It is the difference between the measured value of a quantity and its true value, indicating how far off a measurement is from the correct value. It is essentially the opposite of accuracy and can be expressed as an error, frequently a percentage of the full-scale reading of an instrument. This inaccuracy can be caused by factors like instrument faults, random fluctuations, and human error.
Measurement location – It is a specific, defined point or area where a measurement is taken. In engineering, it can refer to a specific spot on a piece of equipment like a pipe. In statistics, a ‘measure of location’ is a statistical value which describes the central tendency of a dataset, such as the mean, median, or mode.
Measurement pillar – Measurement is the third pillar of the quality advantage. An axiom of quality is, ‘one cannot improve what one does not measure’. In every organization, measurements are being done. But in the quality organization, the measurements are needed to track its progress for the right things. The right things for measurements are decided based on the requirements of both the internal and external customers. When people learn to measure quality, they know where and when to take action. They are also being able to document the achievements which result from the quality improvement process. The organization can meet its quality goals if it establishes baselines and charts progress against them. Decisions what to measure and who to measure, are to be heavily influenced by the requirements of the customers. Normally measurement is to be done by those persons who are closest to the work. Also in a quality conscious organization, people make decisions using facts and data then relying on intuition.
Measurement resolution – It is the smallest increment or change which an instrument can detect and display. It represents the smallest possible difference between two readings, and a higher resolution means the instrument can provide more detailed and finely-grained measurements. For example, a ruler marked in millimeters has higher resolution than one marked in centimeters since it can detect smaller changes.
Measurement sensitivity – It is the ratio of the change in an instrument’s output to the change in the input quantity being measured. It indicates an instrument’s ability to detect small variations, with a high sensitivity meaning it can respond to smaller changes in the measured variable. For a given instrument, sensitivity can be expressed as a ratio S = delta ‘y’/delta ‘x’, where ‘S’ is sensitivity, delta ‘y’ is the change in output, and delta ‘x’ is the change in input.
Measurement sensor – It is a device which detects and measures a physical quantity from the environment, such as temperature, pressure, or light, and converts it into a usable output signal, frequently an electrical one. This signal can then be processed, displayed, or transmitted for further analysis or to control another system.
Measurement signal – It is a varying electrical or digital representation of a physical quantity which carries information about the state of a system, such as temperature, pressure, or voltage. It acts as a bridge between a physical phenomenon and an electronic system, frequently needing processing to improve its quality and accuracy for analysis.
Measurement ton – It is a unit of volume, not weight, used in shipping to determine freight costs. It typically equals 40 cubic feet or 1 cubic meter, but the actual calculation can vary based on the shipping organization and the type of cargo.
Measurement uncertainty – It is a parameter which quantifies the doubt in a measurement, indicating the range of values within which the true value is expected to lie with a stated probability. It acknowledges that all measurements are imperfect and provides a quantitative measure of a measurement’s reliability, which is necessary for assessing its quality and suitability for its intended purpose. For example, if a measurement is 10.2 millimeters, the uncertainty can be expressed as 10.2 +/-0.1 millimeters, meaning the true value is believed to be within the range of 10.1 millimeters to 10.3 millimeters.
Measure of central tendency – It is a central or typical value for a probability distribution. It is frequently called averages. The most common measures of central tendency are the arithmetic mean, the median, and the mode. A middle tendency can be calculated for either a finite set of values or for a theoretical distribution, such as the normal distribution. Occasionally people use it to denote the tendency of quantitative data to cluster around some central value.
Measure of effectiveness – It is a metric which assesses how well a system, person, or project achieves its intended objectives and produces desired results. Measures of effectiveness can be quantitative or qualitative, and they help evaluate if the steps taken are proper and lead to success by measuring changes in behaviour, capability, or environment related to a goal.
Measure of performance – It is a quantitative and systematic way to assess how well an individual, group, or organization is achieving its goals and objectives. It involves collecting and analyzing data to evaluate efficiency and effectiveness, which provides insights for decision-making, improvement, and motivation.
Measuring equipment – It consists of all of the measuring instruments, measurement standards, reference materials, auxiliary apparatus and instructions which are necessary to carry out a measurement. The term includes measuring instruments used in the course of inspection and testing, as well as those used in calibration.
Measuring instrument – It is a device or mechanism for determining values or magnitude of a quantity or variable. It is used to determine the present value of a quantity under observation. It is the device which is used for comparing the unknown quantity with the unit of measurement or standard quantity. It can be defined as a machine or system which is designed to maintain functional relationship between prescribed properties of physical variables and can include means of communication to human observer. It not to influence the quantity which is to be measured. Measuring instruments are the technical objects which are specially developed for the purpose of measuring specific quantities. A general property of measuring instruments is that their accuracy is known. Measuring instruments are divided into material measures, measuring transducers, indicating instruments, recording instruments, and measuring systems. Measuring instruments can be either (i) analog instrument, or (ii) digital instrument. In the analog instrument, the measured parameter value is displayed by the moveable pointer. The pointer keeps moving continuously with the variable parameter / analog signal which is measured. The reading is inaccurate because of parallax error (parallel) during the reading. In the digital instrument, the measured parameter value is displayed in decimal (digital) form and the reading can be read through in numbers form. Hence, the parallax error is not existed and terminated. The concept used for digital signal in a digital instrument is logic binary ‘0’ and ‘1’.
Measuring mechanism – It is a device or system designed to get accurate measurements by converting a physical property into a quantifiable value. It can be a simple instrument like a ruler or a complex system with multiple components which detect, convert, and process a signal to produce a measurement outcome. These mechanisms are used in several fields, to produce reliable data.
Measuring method – It is a specific procedure or technique used to determine the size, quantity, or degree of something by comparing it to a standard unit or using a measuring instrument. These methods vary based on the object being measured and the needed precision, and they can be broadly categorized into direct (e.g., using a ruler) and indirect (e.g., using a formula) techniques. These are necessary for gathering data, ensuring quality, and making comparisons across different fields like engineering, and project management.
Measuring sensor – It is a device which detects a physical quantity, such as temperature, pressure, or distance, and converts it into a measurable signal, typically an electrical one. This signal can be analog (like a voltage) or digital, and it can be used for monitoring, control, or further processing to provide information about the physical environment.
Measuring tape – It is a long, flexible ruler which is used to measure length or distance. It normally consists of a ribbon of cloth, plastic, fibre-glass, or metal strip with linear measurement markings.
Measures – These refer to either the quantifiable data used to track performance or the specific actions taken to manage change, policies, or processes. In the first sense, measures are raw numbers like sales figures or customer complaints, while in the second, they are deliberate steps like implementing a new work procedure or grouping related system changes. The term’s specific meaning depends on the context, but it always involves some form of measurement or planned action.
Mechanical abrasion – It is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Mechanical abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.
Mechanical activation – It is the acceleration or initiation of a chemical reaction by mechanical exposure of a nascent solid surface. Metal cutting (machining) is an effective method of exposing large areas of fresh surface.
Mechanical adhesion – It is the adhesion between surfaces in which the adhesive holds the parts together by interlocking action.
Mechanical advantage – It is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to get a desired amplification in the output force. The model for this is the law of the lever. Machine components designed to manage forces and movement in this way are called mechanisms. An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal machine does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors which take into account departures from the ideal.
Mechanical agitation – It is the process of using mechanical force to stir or mix substances, such as liquids, solids, and gases, to improve mass transfer, promote uniformity, and facilitate chemical reactions. It is achieved by rotating a shaft with an impeller, propeller, or vane inside a container, which creates a fluid flow to mix the contents. This process is used in several applications, from industrial mixing and chemical reactors.
Mechanical alignment – It is a method of aligning the geometrical axis of the electron microscope by relative physical movement of the components, normally as a step preceding magnetic or voltage alignment.
Mechanical alloying (MA) – It is a powder metallurgy technique where powder particles are repeatedly welded, fractured, and re-welded in a high-energy ball mill to synthesize new alloys. This solid-state process allows for the creation of unique microstructures and metastable phases, including supersaturated solid solutions and amorphous phases, that are not easily achieved through traditional methods. Mechanical alloying is an alternate cold welding and shearing of particles of two or more species of highly differing hardness. The operation is carried out in high-intensity ball mills, such as attritors, and is the preferred method of producing oxide-dispersion-strengthened (ODS) materials.
Mechanical aperture – It is the opening in a camera lens that controls the amount of light entering, expressed as an f-number. It can also refer to the average height difference or void space between two opposing surfaces of a rock fracture, which is a key parameter in understanding how rock masses behave hydro-mechanically.
Mechanical atomizing oil burner – It is a burner which uses the pressure of the oil for atomization.
Mechanical belt splicing – It is a method of joining conveyor belts using mechanical fasteners. Periodic checks are needed for ensuring connections, assess wear, and maintain overall stability.
Mechanical biological treatment (MBT) system – It is a type of waste processing facility which combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion. Mechanical biological treatment plants are designed to process mixed household waste as well as commercial and industrial wastes.
Mechanical blasting process – The process most frequently employs the use of cabinet type equipment. It is available in either batch, semi-automatic or automatic versions. Typically, the cabinet houses one or more blast wheels which direct the abrasive at the steel surface by centrifugal force. The wheel is positioned to ensure maximum coverage and high efficiency of the blast pattern on the steel surface. Clean abrasive, generally air washed and graded, is stored in a hopper. The abrasives flow from the hopper by gravity to a feed funnel and dipper valve which meters the abrasive flow to the impeller. The impeller imparts centrifugal velocity to the abrasive which is then directed through a control cage. The control cage determines the direction and shape of the delivery of the blast pattern on the steel surface. The wheel generally is enclosed in a protective housing to prevent discharge of stray abrasives.
Mechanical bond – It is the adherence of a thermal sprayed deposit to a roughened surface by the mechanism of particle interlocking.
Mechanical boundary condition – It is a specification of the constraints at the edge of a physical system which defines how it interacts with its environment, such as displacements, rotations, or forces. These conditions are important for accurately analyzing how a structure or mechanical system behaves under load, by specifying the allowable conditions at the system’s boundaries. As an example, a ‘clamped’ boundary can prevent any movement or rotation at a point, while a ‘free’ end has no stress or moment applied.
Mechanical cleaning – It is the removing of residues or impurities from steel using mechanical force such as grinding or sand blasting.
Mechanical cleaning systems – These systems are available for the majority of the industrial production applications to remove contaminants and prepare the work surface for subsequent finishing or coating operations. Typical uses include (i) removing rust, scale, dry solids, mold sand, ceramic shell coatings, or dried paint, (ii) roughening surfaces in preparation for bonding, painting, enameling, or other coating substances, (iii) removing large burrs or weld spatter, (iv) developing a uniform surface finish, even when slightly dissimilar surfaces are present, (v) removing flash from rubber or plastic moulding operations, and (vi) carving or decorative etching of glass, porcelain, wood, or natural stone such as granite or marble. Mechanical cleaning systems use different types of abrasive materials which are energized or propelled against the work surface of the part through one of three principal methods namely (i) airless centrifugal blast blade-type or vane-type wheels, (ii) compressed air, direct-pressure dry blast nozzle systems, or (iii) compressed-air, indirect-suction (induction) wet or dry blast nozzle systems.
Mechanical (cold) crack – It is a crack or fracture in a casting resulting from rough handling or from thermal shock, such as which can occur at shake-out or during heat treatment.
Mechanical compatibility – It is a principle in engineering which ensures parts or materials can work together without causing failure. It needs which elements have sufficient strength for their intended use and are properly matched in terms of physical properties like stiffness, strain, and stress to ensure a continuous, cohesive deformation without gaps or overlaps. For example, in structural repairs, the new material’s properties are to be similar to or less than the original substrate to prevent damage.
Mechanical component – It is a shaped body which is pressed from metal powder and sintered wherein self-lubrication is not a primary property. It is a part but not an oil-impregnated bearing.
Mechanical coupling – It is a device used to connect two shafts to transmit power, torque, and motion from a driving component to a driven one. Couplings are used to join shafts, but can also accommodate and compensate for shaft misalignment, absorb vibration, and facilitate maintenance. They are categorized as either rigid, which needs precise alignment, or flexible, which can tolerate some misalignment.
Mechanical creep – It is the slow, permanent deformation of a solid material under a constant stress, even if the stress is below the material’s yield strength. This time-dependent phenomenon is most significant at high temperatures, typically above 40 % of the material’s melting point, but can also occur in soft materials at room temperature over a long period. Creep is a critical design consideration, as it can lead to component failure over time.
Mechanical cutter – It is a device or tool which uses physical force to cut materials, as opposed to a thermal method like a laser. This can range from simple manual tools to complex, power-driven machines like guillotines, saws, and milling machines. They work by shearing, sawing, or otherwise separating a work-piece into two or more pieces according to a specific design or length.
Mechanical damage – It is physical harm to a material, object, or system caused by external forces, leading to a loss of material, structural integrity, or function. This can include damage from impacts, punctures, cuts, abrasions, or other physical stresses from things like accidents, construction, or improper handling.
Mechanical damage, rolls – Rolls can have mechanical damage. Mechanical damage in rolls can take place because of local mechanical overload. It is quite common to find some intrusions, bruises, impressions on the rolls. These happen when any foreign material enters the rolls along with the material being rolled. The damage to roll take place when the hardness of the foreign material is high or its size is big enough to cause a deep impression on the rolls. In case of deep roll impression, it becomes necessary to machine the rolls.
Mechanical damage, wire rod – Striations, abrasion, and gouging of the rod surface and bruising of the cross section are classed as mechanical damage. Also, due to the mechanical damage, sections of entire coils are kinked or distorted. The defect can be recognized with the naked eye. After leaving the finished stand, the wire rod comes into contact with several mechanical auxiliary and conveying installations such as driving mechanisms, reels push-off gear, suspension chains, conveyer belts, hook conveyers, transfers, and collecting gear. During all these operations, the wire rod is in danger of being getting damaged.
Mechanical damping – It is the process of dissipating energy in a vibrating system, causing oscillations to decrease in amplitude over time until they stop. This dissipation of energy can occur through mechanisms like friction, fluid viscosity, or internal molecular interactions, frequently converting the vibrational energy into heat. It is a crucial concept in engineering for controlling vibrations.
Mechanical deformation – It is the change in the shape or size of an object when subjected to external forces. It can be temporary, where the object returns to its original shape once the force is removed (elastic deformation), or permanent, where the object retains its new shape (plastic deformation). The type of deformation depends on the material, the force applied, and the temperature.
Mechanical degradation – It is the deterioration of a material caused by physical forces like stress, shear, or impact, which break the material’s molecular chains and reduce its overall strength and viscosity. This process is frequently irreversible and can occur in different materials, including polymers, batteries, and even rocks. The forces involved can be external, such as abrasion from waves on plastic debris, or internal, such as the stresses which build up in battery electrodes during charging and discharging.
Mechanical descaling processes – These processes are normally used for the removal of scale from the steel rods in the steel rod drawing industry. These processes carry out descaling of steel by (i) reverse bending deformation, (ii) shot-blasting, and (iii) combination of reverse bending and shot blasting.
Mechanical design – It is the process of creating functional and durable mechanical parts, components, and systems by applying principles of science and engineering. It involves a systematic, iterative process of problem-solving to develop, test, and refine designs that meet specific requirements for performance, safety, and user experience.
Mechanical dewatering – It is the process of using mechanical force to separate water from a solid material, which is normally used to reduce volume and increase solids content in applications like waste-water treatment sludge. Methods include applying pressure (such as with screw presses) or centrifugal force (using centrifuges) to remove excess water, making the material easier to transport, handle, or dispose of. This process is frequently more energy-efficient than thermal dewatering but it cannot achieve the same dryness for all materials.
Mechanical disintegration – it is the process of reducing metal powder particle sizes by mechanical means.
Mechanical disordering – It is the process of destroying long-range atomic order in a material through mechanical means, such as deformation or high-energy milling, to create a more disordered, nano-crystalline, or even amorphous structure. It is a phenomenon observed in crystalline alloys and is a key aspect of processes like mechanical milling, where a crystalline solid is ground into a powder to reduce its structural order.
Mechanical dispersion – It is the spreading of a solute within a flowing fluid because of the variations in flow velocity caused by the physical structure of the medium. In porous media, this occurs since the fluid moves at different speeds through different pore spaces, creating mixing along the flow path and spreading the solute. A different definition in materials science refers to dispersing solid particles into a liquid by using mechanical shearing forces, frequently through methods like ball milling.
Mechanical draft – It is the negative pressure created by mechanical means.
Mechanical draft cooling tower – It is a type of cooling tower which uses power-driven fans to force air circulation for water cooling, making it more effective than natural draft towers. There are two main types: induced draft, with fans at the top that pull air up, and forced draft, with fans at the bottom that push air in. These are used in industries like power plants, chemical plants, and for large HVAC (heating, ventilation, and air conditioning) systems.
Mechanical drive – It is a system which transmits mechanical power from a source, like an electric motor or engine, to a machine to adjust its speed and torque. It uses components like gears, belts, and chains to change the speed and torque ratio, frequently increasing torque while decreasing speed, to match the machine’s operational needs. These are used in a wide range of applications, from industrial equipment like compressors and pumps.
Mechanical efficiency – It is a dimensionless ratio which measures the efficiency of a mechanism or machine in transforming the power input to the device to power output. A machine is a mechanical linkage in which force is applied at one point, and the force does work moving a load at another point. At any instant the power input to a machine is equal to the input force multiplied by the velocity of the input point, similarly the power output is equal to the force exerted on the load multiplied by the velocity of the load. The mechanical efficiency of a machine (frequently represented by the Greek letter etaη) is a dimensionless number between 0 and 1, i.e., the ratio between the power output of the machine and the power input.
Mechanical energy – It is the total energy an object possesses because of its motion (kinetic) or position (potential). It is the sum of its kinetic energy and potential energy and is the energy an object has the ability to do work.
Mechanical engineer – It is a professional who applies the principles of physics, math, and materials science to design, develop, build, and test mechanical systems, devices, and machines. This role involves the entire product lifecycle, from initial concept and computer-aided design to manufacturing and maintenance, and is crucial in a wide range of industries.
Mechanical engineering – It is engineering discipline which deals with the physical machines which involves force and movement. It is an engineering branch which combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and maintain mechanical systems. Mechanical engineering needs an understanding of core areas including mechanics including mechanics, dynamics, thermodynamics, materials science, design, structural analysis, and electricity. In addition to these core principles, mechanical engineers use tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), computer-aided engineering (CAE), and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems.
Mechanical environment – It refers to the physical conditions and forces which influence a system, whether it is a product, or an industrial work-space. This includes factors like shock, vibration, acceleration, and spin, especially in engineering. In a work-place, it involves the physical surroundings of machinery, equipment, and tools.
Mechanical equilibrium – It is a state of an object in which the net force on the object is zero. By extension, a physical system made up of several parts is in mechanical equilibrium if the net force on each of its individual parts is zero. In addition to defining mechanical equilibrium in terms of force, there are several alternative definitions for mechanical equilibrium. In terms of momentum, a system is in equilibrium if the momentum of its parts is all constant. In terms of velocity, the system is in equilibrium if velocity is constant. In a rotational mechanical equilibrium, the angular momentum of the object is conserved and the net torque is zero.
Mechanical equipment – It includes any device, tool, or machine which uses mechanical force to perform a task, frequently involving moving parts powered by a motor, engine, or electricity. This broad category includes large-scale machinery like excavators and elevators, and specialized tools for manufacturing like lathes and welding machines. The main purpose of mechanical equipment is to make work easier and more efficient.
Mechanical erosion – It is also known as physical erosion. It is the process where rocks and soil are broken down and transported without a change in their chemical composition, primarily by physical forces like wind, water, ice, and gravity.
Mechanical erosion control – It involves using physical structures and techniques, like terracing, bunds, and diversion drains, to manage water flow and prevent soil erosion.
Mechanical expander – It is a device used to physically increase the diameter of a pipe or tube, frequently to fit it securely into a tube sheet in applications like heat exchangers or boilers, or to size large welded pipes to their required diameter. This process involves plastic deformation of the material.
Mechanical factor – It is an element which involves forces, stress, strain, or the mechanics of a machine or structure. These factors can refer to the critical parameters which influence a material’s performance, such as its strength and stiffness, or the physical attributes of a machine which can lead to failure or accidents.
Mechanical fastener – It is a hardware device which joins or affixes two or more objects together, typically in a non-permanent way which allows for disassembly. These fasteners create a physical bond using force and / or the geometry of the fastener itself. Unlike methods like welding or adhesives, mechanical fasteners are designed to be removable and reusable, making them ideal for applications needing assembly, disassembly, and maintenance. In case of conveyor belts, It is a mechanical device used to join the ends of belting. Sometimes it is also used for temporary emergency repairs.
Mechanical fatigue test – It is a process to evaluate a material’s durability and resistance to failure when subjected to repeated or fluctuating stress cycles. By simulating real-world conditions through cyclic loading (such as tension, compression, or bending), this test determines how many stress-cycles a material can withstand before it fatigues and potentially fractures. The results are used to predict a material’s fatigue life, strength, and safety in applications where it experiences continuous, varying loads.
Mechanical filter– It is a signal processing filter normally used in place of an electronic filter at radio frequencies. Its purpose is the same as that of a normal electronic filter, i.e., to pass a range of signal frequencies, but to block others. The filter acts on mechanical vibrations which are the analogue of the electrical signal. At the input and output of the filter, transducers convert the electrical signal into, and then back from, these mechanical vibrations.
Mechanical flow diagram – it is also known as a ‘piping and instrumentation diagram’ (P&ID). It is a detailed technical drawing which shows the exact layout of a process system. It includes all mechanical equipment, piping, valves, and instrumentation, along with details like pipeline numbers, sizes, and specifications. Mechanical flow diagrams are developed from more general ‘process flow diagrams’ (PFDs) to provide the necessary detail for mechanical engineers to design and construct the system.
Mechanical friction loss – It is the energy which is dissipated as heat when two moving parts in a system rub against each other. This energy is a form of mechanical loss, meaning it is consumed by resistance and is not converted into useful work, leading to reduced efficiency in devices like engines and pumps.
Mechanical gauge – It is a device which uses mechanical components to measure and indicate a specific parameter, such as pressure, dimensions, or force. Mechanical gauges typically involve physical elements like springs, diaphragms, or tubes that deform under the influence of the measured quantity, with the deformation then converted into a readable output, often displayed on a dial.
Mechanical grinding – It is a process which either reduces solid materials to a smaller particle size through crushing and abrasion or refines a work-piece’s surface using a rotating abrasive wheel. In the first sense, it is used to break down materials into fine powders. In the second, it is a machining process which achieves high precision and fine finishes on metal parts.
Mechanical homogenizer – It is a device which uses mechanical force, such as shearing, impact, or cavitation, to break down and mix substances into a uniform, stable mixture. It achieves this by creating small droplets or particles from larger ones, preventing components from separating and creating a consistent texture and appearance. Examples include rotor-stator mixers, blade homogenizers, and high-pressure homogenizers.
Mechanical hysteresis – It is the energy absorbed in a complete cycle of loading and unloading within the elastic limit and represented by the closed loop of the stress-strain curves for loading and unloading. It is sometimes referred to as elastic hysteresis.
Mechanical impedance – It is the measure of how much a system opposes changes in its velocity when a force is applied. It is defined as the ratio of the applied force to the resulting velocity at the point of application, much like how electrical impedance is the ratio of voltage to current. It quantifies the stiffness, damping, and mass characteristics of a system.
Mechanical instruments – The instruments which came into existence in early days were of mechanical nature. The principles on which these instruments worked are even in use today. The earliest scientific instruments used the same three essential elements as the modern instruments use. These elements are (i) detector, (ii) intermediate transfer device, and (iii) indicator, recorder or a storage device. These instruments are very reliable for static and stable conditions. There are a large number of possibilities for mechanical instruments. For example, the instruments can be calipers, micrometers, scales, measuring tapes, and lasers, etc. for measuring distances, pressure gauge for measuring pressure, strain gauges for measuring how much a part is stretched or compressed when a load is applied, tachometer for measuring the rotational speed, multi-meter for measuring electrical voltages and currents, and many others. The disadvantage associated with the mechanical instruments is that they are unable to respond quickly to measurements of dynamic and transient nature. These instruments have several moving parts which are rigid, heavy and bulky and thus they have a large mass. The mass presents inertia problems and hence these instruments cannot follow the rapid changes which are involved in dynamic measurements. Another disadvantage of mechanical instruments is that most of them are a potential source of noise and cause sound pollution. Mechanical instruments are simple in design and application. They are normally durable and relatively cheaper. No external power source is needed for their operation. They are normally quite reliable and accurate for measurements under stable conditions.
Mechanical interaction – It is the effect of two or more objects exerting forces on each other, causing changes in their motion, position, or state. This can be a direct contact (like a collision) or an indirect force (like gravity) and is a fundamental concept in physics and engineering, used to analyze how systems of moving parts function.
Mechanical joint – It is a physical connection which holds two or more mechanical parts together, allowing them to function as a single unit. These joints are used in machines and systems to connect components, enabling controlled movement while providing structural integrity. Examples include flanged joints, screwed joints, and flared joints, which can be permanent, semi-permanent, or temporary.
Mechanical lifters – They are composed of two or more rigid parts which move in tandem when manually actuated to secure the load.
Mechanical linkage – It is an assembly of rigid bodies, called links, connected by joints to form a movable system which transmits force and motion. These linkages can convert one type of motion (like rotation) into another (like linear motion) and are fundamental in creating machines and mechanisms.
Mechanical load capacity – In many applications the pressure measuring instruments are sometimes exposed to significant shock and vibration loadings. Vibration loads are oscillating mechanical loads of longer duration. In contrast, shock is considered as an impulse wave which decreases quickly compared to vibration. Strong vibrations have an effect when using pressure measuring instruments. Shocks occur, for example, during its application in machines with high accelerations during operation, such as solid forming presses or drop forges. For the pressure measuring instrument to be used safely in applications with strong vibrations and / or shocks, it is to withstand these loads. The vibration resistance of industrial pressure transmitters is usually in the range of 10 to 20 times the acceleration due to gravity (10 g to 20 g). Nowadays, the shock resistance of industrial pressure transmitters is at several hundred ‘g’.
Mechanical loss – It is the energy lost because of the friction and other non-productive factors within a machine, such as in engines, electric motors, or gears. This energy is dissipated as heat and other forms, reducing the output power available for the intended work. These losses are mainly caused by friction between moving parts and windage (air resistance).
Mechanically assisted degradation – It is defined as any type of degradation which involves both a corrosion mechanism and a wear or fatigue mechanism. There are five major such forms of degradation which are erosion, fretting, fretting fatigue, cavitation and water drop impingement, and corrosion fatigue.
Mechanically fastened repair – It is a structural repair which uses physical fasteners like bolts, screws, or rivets to join a patch over a damaged area, transferring mechanical loads around the original damage. This method is common for materials like composites and is favoured for its simplicity, potential for disassembly, and ability to be done in the field with relatively simple tools.
Mechanically flexible couplings – In general, these couplings obtain their flexibility from loose-fitting parts and / or rolling or sliding of mating parts. Hence, they normally need lubrication unless one moving part is made of a material that supplies its own lubrication needs (e.g., a nylon gear coupling). Also included in this category are couplings that use a combination of loose-fitting parts and / or rolling or sliding, with some flexure of material.
Mechanical metallurgy – It is the science and technology dealing with the behaviour of metals when subjected to applied forces. It is frequently considered to be restricted to plastic working or shaping of metals.
Mechanical milling – It is a process of crushing, grinding, or pulverizing materials using mechanical force to reduce particle size. It involves using equipment like ball mills or other mills with rotating surfaces to impact and break down a material, which can be used to produce nano-particles, create new materials by blending particles, and improve material properties.
Mechanical mixing – It is the process of combining two or more substances using physical force to create a mixture whose components can be separated by mechanical means. This can involve using machinery to blend ingredients, such as a ball mill for powders, with the goal of achieving a uniform distribution.
Mechanical model – It is a representation of a physical system’s structure and properties, used for simulation and design. It can be a geometric representation of a 3D design, like a CAD (computer-aided design) model, or a more abstract model like the quantum mechanical model of an atom, which uses probabilities to describe the location of electrons. The purpose is to understand, analyze, and optimize a system’s performance and functionality.
Mechanical over-load – It is the failure of a component or system because of the exceeding its design limits, resulting from excessive forces, stress, or other loads. It can cause a single event failure or lead to permanent deformation and damage. This can occur when a product is weaker than expected or when the applied load is higher than the intended design capacity.
Mechanical over-ride – It consists of a mechanical device fitted to an actuator for operating the valve when the normal motive power is not available.
Mechanical phenomenon – It is a physical occurrence related to the equilibrium or motion of objects. It involves how materials and objects behave under forces, which includes everything from the simple motion of a falling object to the complex deformation of a material under stress.
Mechanical plating – It is the plating wherein fine metal powders are peened onto the work by tumbling or other means. It is a method for coating ferrous metals, copper alloys, lead, stainless steel, and certain types of castings. The process applies a malleable, metallic, corrosion-resistant coating of zinc, cadmium, tin, copper, or aluminum. Combinations of metals can be applied as co-deposits or as ‘sandwich’ layered deposits. Mechanical plating is referred to by a variety of names, including peen plating, impact plating, and mechanical galvanizing. Mechanical plating frequently can solve engineering, economic, and pollution-related plating problems. It offers a straight-forward alternative method for achieving desired mechanical and galvanic properties with an extremely low risk of hydrogen embrittlement. In some situations, it offers a potential cost advantage over electro-plating. Mechanical plating is accomplished at room temperature, without the electrical charge passing through the plating medium which is necessary with electro-plating or electro-coating. The metallic coating is produced by tumbling the parts in a mixture of glass beads, metallic dust or powder, ‘promoter’ or ‘accelerator’ chemicals, and water. The glass beads provide impacting and hammering energy, which serves to pound the metallic particles against the surfaces of the parts. The result is a tight, adherent metallic coating produced by ‘cold welding, fine, powdered metallic particles to the surfaces of parts.
Mechanical polishing – It is a process which yields a specularly reflecting surface entirely by the action of machining tools, which are normally the points of abrasive particles suspended in a liquid among the fibres of a polishing cloth.
Mechanical press – Mechanical press belongs to a class of machine tools which encompass a wide range of different machine types. Primarily, the mechanical press transforms the rotational force of a motor into a translational force vector that performs the pressing action. Hence, the energy in a mechanical press comes from the motor. These types of presses are normally generally faster than hydraulic or screw presses, (actually the screw press can also be classified as a mechanical press). Unlike some presses, in a mechanical press, the application of force varies in both speed and magnitude throughout the distance of the stroke. When performing a manufacturing operation using a mechanical press, the correct range of the stroke is essential. In mechanical presses, a crank, knuckle joint, scotch yoke, or moving-wedge mechanism is used to apply a vertical squeezing motion between the upper moving die and a lower fixed die.
Mechanical press brake – It is a press brake using a mechanical drive consisting of a motor, flywheel, crankshaft, clutch, and eccentric to generate vertical motion.
Mechanical pressure gauges – In mechanical gauges, the motion generated by the pressure sensing device is converted by mechanical linkage into dial or pointer movement. The better gauges provide adjustments for zero, span, linearity, and sometimes temperature compensation for mechanical calibration. High-accuracy mechanical gauges take advantage of special materials, balanced movements, compensation techniques, mirror scales, knife-edge pointers, and expanded scales to improve the precision and accuracy of readings. The most accurate mechanical gauges, test gauges, are used as transfer standards for pressure calibration, but for applications requiring remote sensing, monitoring, or recording they are impractical. Their mechanical linkages also limit their frequency response for dynamic pressure measurements.
Mechanical properties – These are the properties of a material which reveal its elastic and inelastic (plastic) behaviour when force is applied, thereby indicating its suitability for mechanical (load-bearing) applications. Examples are elongation, fatigue limit, hardness, fracture toughness, tensile strength, and yield strength. Some definitions exclude elastic constants (including the modulus of elasticity) from a list of mechanical properties since the value of these constants is controlled by interatomic bonding forces and is therefore a physical property. Others include the elastic constants and use a definition of mechanical properties which include the requirement of the imposition of a force or a deformation to the material. In any event, most mechanical properties are highly (micro) structure sensitive, except for the elastic constants, which in macroscale polycrystalline materials usually do not vary significantly with micro-structure.
Mechanical protection – It refers to measures and devices designed to safeguard equipment and structures from physical damage caused by impacts, stress, or wear. This can include physical barriers like fences or guards, protective enclosures and tubing for cables, and specific devices to prevent damage from events like short circuits or high-speed operation. The term is also used for systems which protect against over-speeding or excessive mechanical stress, such as in a power transformer or an engine.
Mechanical pump – It is a device which uses mechanical action to move fluids (liquids or gases) from one location to another. These pumps typically rely on moving parts, powered by an engine or electricity, to create pressure and force fluids to flow in a specific direction. Mechanical pumps may be submerged in the fluid they are pumping or be placed external to the fluid.
Mechanical rectifier – It is an electro-mechanical device for converting alternating current to direct current by using sets of contacts which operate in synchronism with the alternating current.
Mechanical reinforcement – It is the process of improving a material’s mechanical properties, such as strength and stiffness, by adding a second material (the reinforcement). This is frequently seen in composite materials, where strong fibres or particles are embedded in a matrix material (like concrete or polymer) to create a new material which is superior to its individual components. Examples include adding steel bars to concrete to increase its tensile strength or embedding carbon fibres in a polymer to make a lightweight, strong composite.
Mechanical removal process – It is a method used to remove material from a work-piece, typically involving cutting tools to achieve desired shapes and surface finishes, as exemplified by conventional and ultrasonic-assisted machining techniques.
Mechanical resistance – It is a material’s ability to withstand external mechanical forces without breaking, deforming, or fracturing. It encompasses various properties which resist movement and stress, such as hardness, elasticity, viscosity, and the effects of friction and drag. In engineering, it is a critical factor in designing structures and components to ensure they can safely handle applied stresses like pressure, tension, or vibration.
Mechanical rigidity – It is a material’s ability to resist deformation, such as bending, twisting, or shearing, when an external force is applied. It is a measure of how much a solid resists changing its shape or size.
Mechanical schematic diagrams – A mechanical schematic diagram symbolically depicts elements of the unit, assembly, or system involved and displays the relation of each element by interconnecting lines. The elements are normally arranged functionally or they are actually arranged as in their assembly or installed position. The mechanical schematic diagram depicts mechanical and other functional operation, structural loading, fluid circuitry, or other functions using appropriate standard symbols and connecting lines. It is a design information drawing. It is made when operating principles cannot be readily determined from a study of the assembly drawing. It illustrates design information for (i) hydraulic or pneumatic systems, (ii) complex mechanical systems (complex arrangement of gears, clutches, linkages, and cams, etc.), (iii) rigging instructions, and (iv) critical structural items to display loading or lifting data.
Mechanical seal – It is a device which prevents the leakage of fluids along rotating shafts. Sealing is accomplished by a stationary primary-seal ring bearing against the face of a mating ring mounted on a shaft. Axial pressure maintains the contact between seal ring and mating ring.
Mechanical sensor – It is a device that detects mechanical changes in its environment, such as force, pressure, vibration, or speed, and converts them into an electrical signal for analysis. These sensors are used across several fields, enabling precise monitoring and control. Examples include accelerometers, strain gauges, pressure sensors, and speedometers.
Mechanical separation – It is the process of separating components from a mixture using physical forces and properties like size, shape, or density, without a chemical change. Common techniques include filtration, sedimentation, sieving, and centrifugation, which are used to purify products, concentrate materials, or remove impurities in industries.
Mechanical-shaker type of fabric filters – In this type of filters, tubular filter bags are fastened onto a cell plate at the bottom of the filter and suspended from horizontal beams at the top. Dirty gas enters the bottom of the filter and passes through the filter, and the dust collects on the inside surface of the bags. Cleaning is accomplished by shaking the top horizontal bar from which the bags are suspended. Vibration produced by a motor-driven shaft and cam creates waves in the bags to shake off the dust cake. These filters can operate intermittently or continuously. Intermittent units can be used when processes operate on a batch basis. When a batch is completed, the filter can be cleaned. Continuous processes use compartmentalized filters. When one compartment is being cleaned, the exhaust gas flow can be diverted to other compartments. In these filters, there must be no positive pressure inside the bags during the shake cycle. Pressures (as low as 0.5 millimeter water gauge) can interfere with the cleaning process of the bags. The air to cloth ratio for these filters is relatively low. Hence, the space requirements are quite high.
Mechanical shear – It is a machine which cuts sheet metal, plates, or bars by applying shear stress through the movement of blades or a die and punch. These machines utilize a mechanical transmission system, such as a flywheel or crank mechanism, to drive the cutting action. They are normally used in manufacturing for several applications, including cutting metal into desired shapes and sizes.
Mechanical shock – It is a sudden, short-duration impact or jolt of mechanical energy applied to an object or system, which can cause damage, deformation, or malfunction. It is a non-periodic event, distinct from continuous vibration, and can occur from events like dropping a package, or being struck.
Mechanical signal – It is a physical force, pressure, or tension which conveys information by triggering a cellular or mechanical response. It can be transmitted through mechanical systems, such as the physical movement of a railway signal arm. These signals can involve physical components like gears and levers.
Mechanical spalling – In refractory brick it is caused by the stresses resulting from impact or pressure.
Mechanical spectroscopy – It is a non-destructive technique which studies how materials respond to a time-dependent mechanical force, such as stress or strain. By measuring the energy absorbed and dissipated by a material in response to this mechanical perturbation, it provides insights into its viscoelastic properties and the dynamics of microscopic processes like defects or molecular motion. It is used as a material characterization tool, similar to how dielectric spectroscopy uses an electric field instead of a mechanical one.
Mechanical stability – It is an object’s or system’s ability to resist deformation or collapse and maintain its shape, form, or equilibrium when subjected to external forces. It is a fundamental property in engineering which ensures the safety and durability of structures and machinery, determined by factors like strength, stiffness, and the system’s tendency to return to its original state after a disturbance.
Mechanical stability of a grease – It consists of grease shear stability tested in a standard rolling tester.
Mechanical stage – It is a device which is provided for adjusting the position of a sample, normally by translation in two directions at right angles to each other.
Mechanical steam traps – These traps are operated by changes in fluid density. This range of steam traps operates by sensing the difference in density between steam and condensate. These steam traps include ‘ball float traps’ and ‘inverted bucket traps’. In the ‘ball float trap’, the ball rises in the presence of condensate, opening a valve which passes the denser condensate. With the ‘inverted bucket trap’, the inverted bucket floats when steam reaches the trap and rises to shut the valve. Both are essentially ‘mechanical’ in their method of operation.
Mechanical stirring – It is a mixing technique which uses a physical object, like an impeller or a magnetic bar, to agitate a fluid or mixture. This agitation creates turbulence and movement, which promotes the uniform distribution of components, enhances reaction rates, and can be used in applications ranging from laboratory solutions to industrial processes like metal casting and fuel oil heating.
Mechanical strain – It is the measure of deformation, or relative change in shape and size, of a material because of an external force (stress). It is defined as the ratio of the change in a dimension to the original dimension, such as the change in length divided by the original length (delta L/L). This quantity is dimensionless and is frequently expressed as a percentage or a decimal.
Mechanical stresses – Properties related to mechanical stresses are having importance since they determine the strength of the refractories under different service conditions. The important refractory properties for the mechanical stresses are cold modulus of rupture and deformation modulus, crushing strength, abrasion resistance, porosity, and density.
Mechanical structure – It is the physical framework or arrangement of components in a machine or system designed to withstand forces, maintain stability, and support loads. It is defined as the framework and mechanical support for machine components, including elements such as the machine base, column, worktable, and carriages. It aims to achieve high structural stiffness, good damping properties, and long-term stability while minimizing heat deformation and environmental effects.
Mechanical system – It is a collection of interconnected components which use mechanical principles like forces and motion to perform a specific function or task. These systems can range from simple machines like levers and gears to complex assemblies.
Mechanical testing – It is the methods by which the mechanical properties of a metal are determined.
Mechanical thermal expression process – This process is the combination of mechanical expression and thermal dewatering process. It is a method which uses mild heat and mechanical compression. For getting substantial benefit from mechanical thermal expression process, it is necessary to heat the lignite coal above the normal boiling temperature of water. However, the processing temperature is to be low enough to prevent significant release of organics into the product water. Around 10 % to 60 % of the initial water is removed during the stage of mechanical compression. The compressive pressure is the major factor influencing the quantity of water removed. Mechanical dewatering process is held in back-pressure to prevent evaporation, ensuring that the water is removed only by mechanical forces. Further moisture reduction is achieved by flash evaporation in the processed lignite coal by exposing it to atmospheric conditions. The mechanical thermal expression process results into the removal of water which is around 75 % maximum of the original moisture content. The mechanical thermal expression process has certain drawbacks such as (i) the need for prior grinding of coal, (ii) the need for clean water produced, (iii) time consuming, and (iv) high investment and operating costs.
Mechanical tools – These are devices used for the removal of surface layers of materials to access unaltered material underneath, including devices such as geologist’s hammers and grinders. These tools facilitate the exploration and analysis of geological samples by revealing information about rock formation processes and environmental conditions. These are power-driven machines used to cut, shape, or finish materials. These tools work by selectively removing material through processes like cutting, drilling, and grinding, or by deforming the material through processes like shearing and squeezing.
Mechanical torque – It is the rotational force produced by a prime mover, balanced by an electro-magnetic torque resulting from the interaction of magnetic flux and current in the stator windings. It is to be transmitted through the rotor shaft and withstood by the stator during operational and fault conditions.
Mechanical transducer – It is a type of transducer which converts mechanical energy into another form of energy, frequently an electrical signal. These transducers are used to measure physical quantities like force, pressure, displacement, or acceleration and transform them into a more easily measurable signal, frequently electrical.
Mechanical transmission – It is the transfer of mechanical energy between components of a machine. It involves using components like gears, belts, and chains to transfer rotational motion and torque, potentially changing speed, torque, or direction.
Mechanical treatment technology – It involves using physical and mechanical processes, like screening, grinding, and settling, to treat wastewater and separate solids from liquids, often as a preliminary step before biological or advanced treatment.
Mechanical tubular product – It includes welded and seamless tubes used for a wide variety of mechanical purposes. It is normally produced to meet specific end-use requirements and hence is produced in several shapes, to a variety of chemical compositions and mechanical properties, and with hot rolled or cold finished surfaces. Majority of the mechanical tubes are available as per specifications of different standards. Mechanical tube is not produced to specified standard sizes, but it is produced to specified dimensions, which can be anything which the customer needs within the limits of production equipment or processes. Controlling tolerances are placed on the outside diameter (OD) and wall thickness for hot finished tube and on outside diameter, inside diameter, and wall thickness for cold finished tube. Size is generally expressed in mm. Specifications for size includes any two of the controlling dimensions namely outside diameter, inside diameter, and wall thickness, but never all three. The chemical compositions normally available in mechanical tubes cover a wide variety of standard grades. In addition to the standard grades, several high strength low alloy (HSLA) grades and unique chemistries are produced to customer specifications. When the steel used, either carbon or alloy steel, needs normalizing or annealing after welding, such operations become a part of the specification. For example, a type of welded structural tubing made from carbon steel with nominal carbon content of 0.50 % is normally normalized.
Mechanical twin – It is a twin formed in a crystal by simple shear under external heating. Mechanical twins are a type of deformation mechanism where a crystal lattice undergoes a mirror-image atomic arrangement along specific planes, accommodating plastic strain. This occurs when dislocation slip, another deformation mechanism, is insufficient, especially at lower temperatures. Essentially, a portion of the crystal lattice rotates to form a ‘twin’ with a mirrored orientation compared to the surrounding material.
Mechanical upsetter – It is a three-element forging press, with two gripper dies and a forming tool, for flanging or forming relatively deep recesses.
Mechanical valves – These valves use mechanical energy in the process of opening and closing the actual valve. Larger valves can be opened and closed using mechanical processes such as levers and pulleys, whereas smaller mechanical valves can be opened or closed via a turning wheel or pulling a level by hand.
Mechanical vapour recompression system – It is an energy-efficient engineering process which uses mechanical energy to compress low-pressure vapour, increasing its temperature and pressure. This compressed, hotter vapour is then used as the heat source for an evaporator, recycling the latent heat and drastically reducing the need for external steam or energy. Mechanical vapour recompression is normally used in industrial processes like waste-water treatment, and chemical production to concentrate liquids by evaporating water.
Mechanical vibrating feeders – The function of these feeders is like the function of electromagnetic vibrating feeders. However, vibrations are created by unbalanced rotating mass, hence tray size, power, force options, and ranges are very large. The tray can be made much stronger and robust, and so they can be used for comparatively difficult bulk materials and also for larger capacities. One can come across mechanical vibrating feeder for capacity up to 1,100 tons per hour of coal or 3,000 tons per hour for iron ore. The material flows in a loose (fluidic) condition and so lumps jamming and forceful abrasion on tray is absent. This is also due to reason that the equipment is not capable in dealing with full extraction of material like apron feeder or belt feeder. The hopper outlet length along tray is of specific (small) dimension, not like long opening in case of belt feeders / apron feeders.
Mechanical vibration – It is the repetitive back-and-forth motion of a mechanical system about an equilibrium position, caused by an external force or internal factors. This oscillation can be seen in machinery, structures, and other mechanical components, and while it can be necessary for a system’s function, excessive or unwanted vibration can lead to performance issues, wear, and potential structural failure.
Mechanical wave – It is a disturbance which travels through a medium by the oscillation of particles within that medium, transferring energy without a net movement of the medium itself. Essentially, it is a wave which needs a physical medium like a solid, liquid, or gas to propagate.
Mechanical wear – It is the removal of material because of the mechanical processes under conditions of sliding, rolling, or repeated impact. The term mechanical wear includes adhesive wear, abrasive wear, and fatigue wear.
Mechanical work – It is the energy transferred to or from an object through the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled. A force is said to do positive work if it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.
Mechanical working – It means the subjecting of metals to pressure exerted by rolls, hammers, or presses in order to change the shape or physical properties of the metal.
Mechanics – It concerns with the relationships between force, matter, and motion among physical objects. Forces applied to objects can result in displacements, which are changes of an object’s position relative to its environment.
Mechanism – It is a device which transforms input forces and movement into a desired set of output forces and movement. Mechanisms normally consist of moving components which can include gears and gear trains, belts and chain drives, cams and followers, linkages, friction devices such as brakes or clutches, structural components such as a frame, fasteners, bearings, springs, or lubricants, and different machine elements such as splines, pins, or keys. In statistical analysis, mechanism is a characteristic which transmits the effect of one variable on another. It is also called an intervening variable or a mediating variable.
Mechanism dynamics – It is the procedure for determining the detailed motions, velocities, and accelerations of the parts in a complex mechanical system. Computer-aided methods, based on the engineering sciences of dynamics and kinematics, are used.
Mechanism of adhesion – It is the combination of processes which cause two surfaces to stick together, involving a combination of molecular, chemical, and physical forces. These forces include mechanical interlocking, chemical bonding (like covalent or hydrogen bonds), electrostatic attraction, and van der Waals forces, which can be affected by factors like surface energy and contact area.
Mechanistic – This method needs the most effort to determine the exact changes in the variables which can lead to changes in other ones using randomized trial data sets. It can also be concluded that mechanistic analysis is hardly inferable. Hence, when people need high precision in the result and the people are to minimize the errors, it can be a choice.
Mechanized mines – In these mines, mining is done to extract ore by using mining equipment and machinery. In these mines. all the operations are mechanized and mining is invariably done through systematic formation of benches by drilling and blasting.
Mechatronics – It consists of combinations of mechanical systems with electronics for sensing and control.
Mechatronic system – It is an integrated design that combines mechanics, electronics, computer control, and software to create products and processes with improved functionality and performance. These systems use sensors to perceive their environment, process that information with embedded computers, and then produce an output, such as motion or force, making them adaptable and intelligent beyond conventional machines. Examples include automated machinery.
Media – In communications, it refers to the channels or tools used to transmit messages between a sender and a receiver. It encompasses different methods, including verbal and non-verbal language, and can involve physical or digital means. Essentially, media are the ways we share information and ideas, bridging the gap between communicators.
Media filters – These filters are used to remove suspended solids and turbidity from the service water. If the turbidity of the service water is higher than 1 NTU (nephelometric turbidity unit), a media filter is needed. The media filter is normally located at or near the upstream of the water treatment system, to protect downstream equipment from the suspended solids.
Median – The median is the middle most number in an ordered series of numbers. It is a measure of central tendency, and is frequently a more robust measure of central tendency, that is, the median is less sensitive to outliers than is the sample mean. If the list has an odd number of entries, the median is the middle entry after sorting the list into increasing order. If the list has an even number of entries, the median is halfway between the two middle numbers after sorting.
Median crack – It is the damage produced in glass by the static or translational contact of a hard, sharp object on the glass surface. The crack propagates into the glass perpendicular to the original surface.
Median fatigue life – It is the middle value when all of the observed fatigue life values of the individual sample in a group tested under identical conditions are arranged in order of magnitude. When an even number of samples are tested, the average of the two middlemost values is used. Use of the sample median rather than the arithmetic mean (that is, the average) is normally preferred.
Median fatigue strength at ‘N’ cycles – It is an estimate of the stress level at which 50 % of the population survives ‘N’ cycles. The estimate is derived from a particular point of the fatigue life distribution, since there is no test procedure by which a frequency distribution of fatigue strengths at ‘N’ cycles can be directly observed. It is also known as fatigue strength at ‘N’ cycles.
Median of a variable – It is the value of the variable such that half of the cases are lower in value and half are higher in value.
Mediterranean climate – It is defined by hot, dry summers and mild, wet winters. This climate type is named for the Mediterranean Basin, but it is also found in other parts of the world. These distinct seasonal patterns are caused by the shifting of high-pressure and low-pressure systems.
Medium – It refers to a means, channel, or substance through which something is conveyed or accomplished, while process signifies a series of actions or steps taken to achieve a specific outcome. It also refers to a substance or material through which energy, like waves or signals, travels or propagates. Medium also refers to the material or substance through which a process, signal, or energy is transmitted or operates.
Medium and high carbon spring steels – These spring steels are the most commonly used materials since they are less expensive. These materials can be easily worked and are readily available. These steels are not suitable for springs operating at high or low temperatures or for shock or impact loading.
Medium-alloy steels – These are a type of alloy steel where the alloying elements typically range from 5 % to 12 %. They are characterized by a combination of alloying elements which improve strength, hardness, and other properties beyond what is achievable with plain carbon steel. Medium-alloy steels are not easily classified because of the wide variety of alloying elements and their combinations.
Medium carbon ferro-manganese (MC Fe-Mn) – This alloy contains 80 % to 85 % of manganese, 1.25 % to 1.50 % of carbon and 1.50 % maximum of silicon. It is normally used in making low carbon manganese steels. It is also used in the production of Hadfield manganese steel, when large quantities of return scrap are being melted.
Medium carbon steels – These steels are similar to low carbon steels except that the carbon content in these steels is higher and normally in the range of 0.31 % to 0.60 % with the manganese content ranging from 0.60 % to 1.65 %. Because of the increased carbon content, the medium carbon steels can be used in the quenched and tempered condition.
Medium cement castable (MCC) – It is characterized by a calcium oxide content higher than 2.5 %.
Medium coking coals – These are those coals which, with or without beneficiation, produce slightly inferior quality coke and when used in the blend with suitable matching coal can produce coke of metallurgical specification.
Medium degradation – It is a process where a substance or material deteriorates because of its interaction with the surrounding medium. This is a broad term, but it normally refers to chemical reactions like hydrolysis or oxidation, triggered by factors in the medium such as water, or pH, which break down the substance’s molecular structure.
Medium sections – These are sectional products whose sizes range between light sections and heavy sections.
Medium-section rolling mill – It is an industrial facility which uses hot rolling to produce steel sections with medium dimensions, such as angles, beams, channels, and flats. These mills take steel billets and shape them through a series of rolling stands to achieve the desired dimensions and profile.
Mega column – It is a large structural element, frequently composite, used in supertall buildings to provide support against gravity and lateral loads. It can be a concrete-filled steel tube or a cluster of steel sections embedded in concrete, with the main goal of making the building rigid. In the context of chemical engineering, ‘mega columns’ refer to very large distillation or mass transfer columns with a diameter exceeding 10 meters and a height higher than 70 meters.
Mega Pascals – It is the SI (International System of Units) unit for measuring the strength of a material and is abbreviated to MPa. Numerically it is exactly equivalent to Newtons/square millimeter.
Megawatt – It is equal to one million watts. The productive capacity of electrical generators operated by a power plant is frequently measured in megawatts.
Meissner effect – It is a phenomenon observed in superconductors where they expel magnetic fields from their interior when transitioning to a superconducting state. This expulsion is a key characteristic of superconductivity and is distinct from the perfect conductivity that would only prevent changes in the magnetic field, not actively eject it.
MEK test – For this test, cotton wool is soaked in MEK solution. 1 kilogram load is applied on the sample and the sample is rubbed by cotton wool up by thumb for 100 times. Cotton wool is re-soaked in the MEK solution after every 25 rubs. The sample is observed for colour coating getting peel off.
Melamine-formaldehyde resin – It is a durable, hard, thermosetting plastic made by combining melamine and formaldehyde. When cured, it creates a strong, heat-resistant material used in laminates, coatings, and moulded articles like dishes, and can also be used to create fire-resistant textiles and flame-retardant particle boards.
Melamine-urea-formaldehyde resin – It is a co-polymer adhesive created by reacting formaldehyde with both melamine and urea. It combines the higher water and weather resistance of melamine resins with the lower cost of urea resins, making it a durable and cost-effective bonding agent for plywood, particle-board, and other wood products. Melamine-urea-formaldehyde resins are used in high-moisture environments and are engineered to have improved moisture resistance compared to standard urea-formaldehyde resins.
Melilite – It refers to a mineral of the melilite group. Minerals of the group are solid solutions of several end-members, the most important of which are gehlenite and akermanite. A generalized formula for common melilite is (Ca,Na)2(Al,Mg,Fe2+)[(Al,Si)SiO7]. It has a yellowish, greenish-brown colour. The name refers to a group of minerals (melilite group) with chemically similar composition, nearly always minerals in akermanite-gehlenite series.
Mellin transform – It is a mathematical transformation which converts a function of a positive real variable into a function of a complex variable. It is essentially a multiplicative version of the two-sided Laplace transform and is particularly useful in analyzing the behaviour of functions at both small and large values. The transform is defined by an integral involving the original function and a power of the variable, and it has an inverse transform which allows for recovery of the original function.
Melt – It is a charge of molten metal or plastic.
Melt atomization – It is a process in which a superheated metal melt is fed through a nozzle and dispersed into fine particles using gas or water pressure, commonly employed in the production of metal powders such as zinc for several applications.
Melt-blown process – It is a one-step method for producing a fine fibrous non-woven web. It involves extruding a molten polymer through a die with numerous small orifices and using high-velocity hot air streams to attenuate the polymer into micro-fibres. These microfibres are then blown onto a collector screen, where they form a self-bonded web through entanglement and cohesive forces.
Melter – It can refer to a person who melts substances or a device which melts substances.
Melt extrusion – It is a manufacturing process which uses heat and pressure to force a material through a shaped die to create a continuous profile. A rotating screw melts and homogenizes a thermoplastic material, such as a polymer or a blend of polymers and active compounds, before pushing it through a die to form a desired shape. The resulting product, which can be in the form of rods, films, tubes, or pellets, has a constant cross-section.
Melt index – It is the quantity, in grams, of a thermoplastic resin which can be forced through a 2.0955 millimeters orifice when subjected to 20.7 Newton (2,160 gram-force) in 10 minutes at 190 deg C.
Melting – It is the process where a solid, when heated to its melting point, absorbs energy and changes into a liquid. This happens since the added heat increases the kinetic energy of the particles in the solid, causing them to vibrate more vigorously until they have enough energy to overcome the forces holding them in a fixed position. Once the forces are overcome, the particles can move past each other, resulting in a liquid state.
Melting behaviour – The melting behaviour of a mould powder strongly influences both the liquid pool depth and the sensitivity towards rim / bear formation. The melting behaviour can be described by the melting trajectory and the melting speed. In both cases, additions of free carbon are considered to be a principal factor. The other main parameter is the flow condition in the mould i.e. the meniscus stability during casting. The liquid pool depth results from the balanced values of the feeding and the infiltration of the mould powder.
Melting front – It is the interface between a solid and liquid state where a phase change is occurring. It is the boundary line which moves as a solid material melt, separating the unmelted solid from the molten liquid. The behaviour of this front is influenced by factors like heat transfer, material properties, and the surrounding environment.
Melting furnaces – These furnaces are used to heat solid materials until they liquefy by generating temperatures above the material’s melting point.
Melting onset – It is the initial temperature at which a material begins to melt, deviating from its solid-state behaviour as it absorbs heat. It is determined by observing the first signs of melting, such as a substance beginning to collapse from a solid to a liquid, or by analyzing a thermal graph (like a differential scanning calorimetry curve) to identify the point where the curve first deviates from its baseline.
Melting point – It is the temperature at which a pure metal, compound, or eutectic changes from solid to liquid. It is the temperature at which the liquid and the solid are at equilibrium.
Melting pot – It is a metal, graphite-clay, or ceramic vessel, frequently a crucible, used to melt and fuse metals or other substances. The term refers to a pot made of material which does not melt easily, used for high-temperature processes like mixing different metals to create an alloy.
Melting pressure – At a stated temperature, it is the pressure at which the solid phases of an element or congruently melting compound can coexist at equilibrium with liquid of the same composition.
Melting range – It is the range of temperatures over which an alloy other than a compound or eutectic changes from solid to liquid. It is the range of temperatures from solidus to liquidus at any given composition on a phase diagram.
Melting rate – It is the quantity of liquid metal which a furnace can produce within a specific time-frame, typically measured in tons per hour. It is a critical parameter like casting and smelting, directly impacting production efficiency, material quality, and cost. The melting rate is not simply the speed at which a metal melts at its specified melting point, but rather a measure of an entire furnace system’s performance.
Melting speed – The melting speed of mould powders is determined using the so-called softening method. With this method, the displacement of a pre-pressed cylinder of mould powder is measured as a function of time at a fixed temperature (1,400 deg C). The method yields qualitative results which can be related to the mould powder composition i.e. the free carbon content of a mould powder.
Melting temperature – It is the temperature at which a pure metal, compound, or eutectic changes from solid to liquid. It is the temperature at which the liquid and the solid are at equilibrium.
Melting tower – It is a part of the continuous tinning line. In this melting tower the process of tin reflow takes place while the electrolytic coated tinplate passes through the tower. In the melting tower section, the temperature of the strip is raised by resistance or induction heating to just above the melting point of tin (231.9 deg C) and then the strip is immediately quenched with cold water. The tin begins to melt and reflows uniformly across the strip. The product now takes on the more typical bright or shiny surface appearance. In case a matte (unmelted) tin finish is needed then the melting tower is turned off. When differentially coated tinplate is being produced then an identifying mark is normally placed on either side of the strip just prior to melting.
Melting trajectory – The melting trajectory of the mould powder is determined using a hot stage microscope. Results are normally given as values for the softening, the melting and the flow temperatures.
Melting zone – It is a localized area of a material (like a metal rod) that is intentionally melted by a heat source to facilitate purification or single crystal growth. The process of zone melting involves moving this narrow, molten zone slowly along the material. As the zone moves, it segregates impurities, which are more soluble in the molten state, into the molten region and leaves a purer solid behind to solidify.
Melt loss – It is the reduction in weight of a material after it has been melted, which occurs because of oxidation, evaporation, or the separation of impurities. This is a critical factor in industries which process materials like metals, as it affects the final yield and valuation of the material.
Melt lubrication – It is the lubrication which is provided by steady melting of a lubricating species. It is also known as phase-change lubrication.
Melt moulding – It is a manufacturing process which involves heating a polymer above its melting point to create a liquid, which is then shaped by a mould before it cools and solidifies. This technique is used to create a wide variety of parts, from simple objects to complex structures, by injecting the molten material into a mould cavity where it cools to take on the shape of the mould. It is normally associated with processes like injection moulding for mass production, but also includes techniques for creating more specialized structures like scaffolds.
Melt pool – It is a region of molten material created by a heat source, such as a laser or arc, and is a critical component in processes like laser welding and additive manufacturing. In additive manufacturing, it is the molten metal pool formed by a laser, which solidifies to create a new layer of the part.
Melt process – It is a physical change where a solid transitions into a liquid state by absorbing heat energy. This occurs at a specific temperature called the melting point, as particles gain enough kinetic energy to overcome the forces holding them in a fixed position. The reverse process is solidification or freezing.
Melt-quenching – It is the traditional technique of glass making and includes mixing of ingredients, heating up to a temperature normally higher than 1,300 deg C and quenching of the glass melt to get a glass frit.
Melt rheology – It is the study of the flow and deformation of polymers in their molten state. It analyzes how a material behaves under stress, combining both viscous and elastic properties to predict how it is processed through methods like injection moulding or extrusion. This understanding is crucial for controlling processability, product structure, and performance. It is critical for determining the processing behaviour of materials.
Melt spinning – It is a process of manufacturing synthetic fibres by melting a thermoplastic polymer, extruding the melt through a spinneret, and then cooling and solidifying the filaments to form yarn. It is used for materials like polyester and nylon and involves heating the polymer until it becomes a viscous liquid, pushing it through tiny holes, and then drawing the solidified filaments to increase their strength.
Melt-through – It means complete joint penetration for a joint welded from one side. Iy is the visible root reinforcement produced in a joint welded from one side.
Melt viscosity – It is the bulk property of a fluid or semi-fluid (melted) polymer which causes it to resist flow. It is given by the shear stress acting on the fluid divided by the rate of shear. Melt viscosity in polymers is normally measured by the melt index.
Member analysis – It refers to the evaluation of the vibration behavior of structural members, utilizing methods such as generalized beam theory (GBT) to solve vibration eigenvalue problems and assess the influence of various conditions on their dynamic characteristics.
Member axis – It is the longer dimension of a beam member, which is considerably larger than the other two dimensions, serving as the central reference line for the structural component.
Member end moments – These refer to the internal moments at the ends of members in a frame structure, which are influenced by factors such as loading and geometry. These moments are critical for the analysis of frame stability and are adjusted for conditions like sway in unsymmetrical frames.
Membrane – It is a selective barrier. It allows some things to pass through but stops others. Such things can be molecules, ions, or other small particles. Membranes can be normally classified into synthetic membranes and biological membranes. Biological membranes include (i) cell membranes (outer coverings of cells or organelles which allow passage of certain constituents), (ii) nuclear membranes, which cover a cell nucleus and (iii) tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants).
Membrane area – It is the total surface area of a membrane used for separation or transfer. It is the necessary surface area for a process like oxygen transfer or water filtration, chosen to balance requirements like mass transfer, selectivity, and resistance to fouling.
Membrane-based gas separation – Advanced membrane-based gas separation systems are currently being developed to combine the gas shift reaction and hydrogen separation in one step. The membrane-based systems employ a water gas shift hydrogen separation membrane reactor (HSMR) to shift the syngas and extract the hydrogen. The maximum temperature of around 475 deg C ensures fast chemical kinetics and good water gas shift equilibrium performance is obtained by continuous removal of the hydrogen product. There are three major classes of inorganic H2 permeable membranes namely (i) ceramic molecular sieving, (ii) dense ceramic ion transport, and (iii) dense metal.
Membrane-based separation technology – It uses a thin, semi-permeable membrane as a barrier to selectively separate substances from a liquid or gas stream. It works by applying a driving force, such as pressure or concentration difference, which causes certain components to pass through the membrane while others are retained. This process is efficient, energy-saving, and used in several applications, including water treatment.
Membrane bioreactors (MBR) – These are combinations of membrane processes like micro-filtration or ultra-filtration with a biological wastewater treatment process, the activated sludge process. These technologies are now widely used for industrial wastewater treatment. There are two types of membrane bioreactor configurations namely immersed and side-stream. Immersed systems are more common in large industrial units, whereas side-stream is limited to smaller units. There are also differences in the membrane employed from hollow fibre, flat plate, and tubular. Immersed membrane bioreactors use hollow fibre or flat plate whereas tubular membranes are used in side-stream membrane bioreactors. Membrane bioreactor produces an equivalent treatment level to an activated sludge process followed by micro-filtration or ultra-filtration. Despite the advantages of membrane bioreactors, there are still challenges in using membrane bioreactors in industrial applications. The advantages of membrane bioreactor are (i) 25 % lower footprint, (ii) replaces the clarifier and gravity filter of conventional systems, (iii) ideal for land constrained sites and lower hydraulic retention time of 4 hours to 8 hours. Membrane bioreactor provides impermeable barrier for solids producing highest quality effluent with biological oxygen demand (BOD) less than 5 milligrams per litre and turbidity of less than 0.1 NTU (Nephelometric turbidity unit). Membrane fouling is one of the major challenges which results in reduced performance and frequent cleaning or membrane replacement leading to increased maintenance and operating costs. All membrane bioreactor need a minimum of fine screens of 3 millimeters. Sludge produced can be difficult to dewater. Sludge retention time is independent of hydraulic retention time. High sludge age of 15 days to 140 days can be obtained. It has modular expandability, less odour, and flexible operation with less susceptible to upsets. The process can be automated.
Membrane characterization – It is the process of analyzing a membrane’s material properties and behaviour to understand its performance. This involves studying its structure, chemistry, morphology, and transport properties to relate them to its function in separation processes. It is a critical step in the design, development, and operation of membranes for applications like water purification, and gas separation.
Membrane chemical degradation – It is the irreversible deterioration of a membrane’s structure and properties because of the chemical attack. This process is driven by chemical reactions, frequently from reactive species like free radicals and contaminants, which break down the membrane’s polymer chains. This leads to a loss of function, including decreased conductivity, thinning, and eventual failure through mechanisms like pinhole formation.
Membrane chromatography – It is a purification technique which uses porous membranes as a stationary phase to separate bio-molecules through convective flow. It is an alternative to traditional chromatography and offers advantages such as rapid processing, reduced costs, and high capacity for large molecules. The separation is based on principles like ion exchange or affinity chromatography, but uses a ‘filter-like’ membrane structure instead of packed resin beads.
Membrane cleaning – It is a process to remove foulants (contaminants) from a membrane’s surface to restore its performance. It involves physical methods like flushing with water or air, and chemical methods using specific acidic, alkaline, or other solutions to dissolve and wash away deposits. The goal is to remove accumulated substances without damaging the membrane, ensuring it continues to provide adequate flux and separation.
Membrane distillation – Alternative new technologies such as membranes are easing even further the removal of ammonia from flushing liquors. Membrane distillation is being investigated worldwide as a highly efficient and affordable technology. Hydrophobic membranes (flat-sheet, hollow fibre, and spiral wound) are preferred for ammonia extraction due to their hydrophobic characteristics, excellent organic resistance, and chemical stability with acidic and alkaline solutions. The strong hydrophobicity of the membrane prevents liquid transportation through it, hence facilitating the separation of species with different vapour pressures. The partial pressure gradients across the membrane results in the transfer of the volatiles from the liquid phase to the vapour phase. As the temperature gradient is maintained across the membrane, the transport of water vapour occurs continuously. Meanwhile, other species remain on the other side of the membrane, hence separating water from the mixture. Conventional flat-sheet porous have been applied for membrane distillation with efficiencies varying between 70 % to 90 %.
Membrane durability – It is the ability of a membrane to maintain its structural integrity and filtration performance over an extended operational period, resisting chemical degradation, physical fouling, and mechanical stress. It is a measure of how long a membrane can function reliably before its performance permanently declines, leading to reduced efficiency or failure. A durable membrane reduces operational costs by needing less frequent replacement or maintenance.
Membrane failure – It is the loss of a membrane’s ability to perform its intended function, such as separation, filtration, or protection. This can result from chemical degradation, mechanical stress, or physical damage, leading to problems like gas cross-leakage in fuel cells, reduced ultrafiltration in dialysis, or loss of water-proofing in building exteriors.
Membrane filtration – It is a physical separation process which uses a semi-permeable membrane to separate contaminants from a liquid or gas stream by applying pressure. It works by physically blocking particles, micro-organisms, and other impurities while allowing desired molecules, such as water, to pass through. The specific contaminants removed depend on the size of the membrane’s pores, and this process is used in industries like water treatment.
Membrane flux – It is the volume of a fluid (or quantity of a solute) which passes through a unit area of a membrane surface per unit of time. It is a measure of a filtration membrane’s processing capacity and is normally expressed in units like litres per square meter per hour.
Membrane fouling – It is the accumulation of unwanted material on a membrane’s surface or within its pores, which degrades its performance by reducing its water flow rate and filtration efficiency. This build-up, caused by things like particles, organic matter, or biological organisms, leads to a decline in the membrane’s ability to function properly and increases operational costs because of the need for cleaning or replacement.
Membrane interface – It refers to the interfacial interaction between different layers or materials in heterogeneous membranes, such as the separation layer-support layer interface in composite membranes and the polymer matrix-filler interface in mixed matrix membranes, which influences the assembly and properties of the membranes.
Membrane load – It is the transfer of forces or tension stress through a flexible, thin element, such as a slab or membrane, to supporting structures without significant resistance to bending. This means the element acts as a carrier, transferring all applied loads directly to adjacent beams or columns.
Membrane performance – It is a measure of a membrane’s effectiveness in a specific separation process, evaluated based on key metrics like flux (how much permeates through per unit area over time) and rejection (how well it blocks specific substances). It represents the balance between a membrane’s productivity (flux) and selectivity (rejection), and can also include factors like permeability, permeance, and longevity.
Membrane rejection – It is the measure of how effectively a membrane separates a solvent from a solute, expressed as the fraction of the solute which is retained by the membrane. It quantifies the membrane’s ability to filter out unwanted substances, like salts or other contaminants, while allowing the solvent (frequently water) to pass through as permeate. A higher rejection percentage means the membrane is more effective at separating the solute from the solvent.
Membrane resistivity – It is a measure of a membrane’s opposition to electrical current flow, specifically for a unit area, with units of ohms per centimeter squared. It quantifies how well the membrane prevents current from passing through it, allowing for the characterization of a material independently of its size. A higher membrane resistivity indicates higher resistance to current flow.
Membrane selectivity – It is the ability of a membrane to control which substances can pass through it, allowing some components of a mixture to cross while preventing others. This is based on properties like the substance’s size, charge, or chemical affinity. In a more technical sense, especially for gas separation, it is frequently defined as the ratio of the permeability of the more permeable gas to the less permeable gas.
Membrane separation – It is a method which utilizes a membrane’s micropores and selective permeability to filter and separate specific substances in waste-water, normally used in treatments such as reverse osmosis, ultra-filtration, and nano-filtration.
Membrane surface – It is the outer layer of a membrane, which can be a synthetic material used for separation processes. It refers to the external boundary which interacts with fluids, affecting its properties like hydrophobicity and performance.
Membrane technology – Membranes are a popular choice for water reuse applications. Costs of membrane systems have reduced dramatically and, coupled with technological advances in membrane design, membrane options and operating limits, the range of applications in water and wastewater treatment is increasing rapidly. In pressure driven membrane filtration, membranes separate the components of a fluid under pressure. The membrane pores, being extremely small, allow the selective passage of solutes. The popularity of membrane processes arises from the fact that they are effective in the removal of both dissolved and suspended solids. A wide range of materials like cellulose acetate, polyamides, poly- sulfones, poly-propylene, nylon, poly-acrylonitrile, poly-carbonate, polyvinyl alcohol, poly-tetra-fluoro-ethylene, ceramic, and metal composites are basically used to produce the membranes. The membrane pore size is the parameter for the degree of selectivity of a membrane. On the basis of the pore size, there are four types of pressure driven membranes. Micro-filtration and ultra-filtration are low pressure applications given their larger pore size. Nano-filtration needs medium pressure, and ‘reverse osmosis, given the smaller pore size, needs significant pressure to push the solute through the membrane.
Memorandum of agreement – It is a written document which formally outlines the terms of a cooperative relationship between two or more organizations for a shared purpose. It details specific responsibilities, contributions, and expectations for each party, frequently serving as a preliminary agreement before a more formal contract is drawn up.
Memorandum of association – It is the foundational legal document for an organization which outlines its purpose, powers, and limitations. It acts as the charter of the organization, defining its objectives and structure, and is a required part of the registration process. The memorandum of association establishes the relationship of the organization with the outside world and includes necessary clauses like name, registered office, objects, liability, and capital.
Memorandum of understanding – It is a formal, non-binding document between two or more organizations which outlines their shared goals, responsibilities, and expectations for a collaboration. It establishes a framework for a future relationship and helps clarify intentions before a legally enforceable contract is drafted, frequently serving as a precursor to formal agreements.
Menstruum method – It is a method of producing multi-carbide powder, such as tungsten carbide + titanium carbide solid solutions, by introducing the individual elements into a molten bath of a non-carbide forming metal such as aluminum or nickel. The multi-carbide which is formed above 2,100 deg C, is slowly cooled in the dispersed condition in the menstruum to room temperature, and finally won by chemical separation.
Mer– It is the repeating structural unit of a polymer.
Mercalli scale – It is a scale of earthquake intensity ranging from ‘I’ for an earthquake detected only by seismographs to ‘XII’ for one causing total destruction of all buildings.
Mercaptan gas – It is also known as thiols. It is a class of organic sulphur-containing compounds known for their strong, unpleasant odour, frequently described as rotten eggs or cabbage. A common example is methyl mercaptan (CH3SH), which is used as a safety measure to add a detectable odour to odourless gases like natural gas.
Mercaptans – These are chemicals containing carbon, hydrogen, and sulphur. They are detectable at concentrations as low as 10 parts per billion. In some cases, mercaptans are used as an additive to odourless gases for detecting the odourless gases. Methyl mercaptan (also known as methanethiol) is a common mercaptan. In addition to carbon, it contains sulphur. Another example of a common mercaptan is ethyl mercaptan which has the formula C2H5SH.
Merchant bar – It is a group of commodity steel shapes which consist of rounds, squares, flats, strips, angles, and channels, which fabricators, steel service centres, and manufacturers cut, bend, and shape into products. Merchant products need more specialized processing than reinforcement bar.
Merchant bar mill – It is a type of steel rolling mill that specializes in producing a variety of long steel products, known as merchant bars, with different cross-sectional shapes like rounds, squares, flats, angles, and channels. These bars are typically used by fabricators to produce a wide range of products for construction and other applications. They are distinguished from reinforcing bar (rebar) by their intended use in structural applications where welding, punching, and forming are common.
Merchant bar quality (MBQ) – It refers to a category of steel bars which are produced for general fabrication and non-critical structural applications where standard steel quality is sufficient. These bars are typically hot-rolled and used in applications which involve bending, forming, punching, and welding. Merchant bar quality products include angles, channels, flats, rounds, and squares.
Merchant market – It is a place where merchants buy and sell goods. In a general sense, it is a market-place for merchants, while in other contexts, it can refer to the segment of the economy where merchants operate or the specific competitive and risk-based markets in which they participate.
Merchant mill – It is a mill, consisting of a group of stands of three rolls each arranged in a straight line and driven by one power unit. It is used to roll rounds, squares, or flats of smaller dimensions than are to be rolled on a bar mill.
Mercury – It is a chemical element It has symbol Hg and atomic number 80. It is also known as quicksilver. It is the only metallic element that is known to be liquid at standard temperature and pressure. It is a toxic pollutant. It is ubiquitous in the environment and is unique among metals in that it is highly volatile. When materials containing mercury are burned, as in coal combustion or waste incineration, mercury is released to the atmosphere as a gas either in elemental form, Hg (O) or oxidized divalent form Hg2+. The oxidized form is present as water-soluble compounds such as mercury chloride (HgCl2) which are readily deposited in the region of their emission. By contrast, Hg (O) is not water-soluble and is required to be oxidized to Hg2+ in order to be deposited. This oxidation takes place in the atmosphere on a time scale of one year, sufficiently long that mercury can be readily transported around the world by atmospheric circulation. Mercury hence is a global pollution issue.
Mercury-arc rectifier – It is a mercury-arc valve, a vacuum tube device which converts alternating current to direct current by an arc in mercury vapour. It has been displaced by solid-state devices, but formerly much used especially in high-voltage direct current transmission.
Mercury column – It is a vertical tube filled with mercury used to measure pressure, mainly atmospheric pressure in a mercury barometer. The height of the mercury column directly corresponds to the pressure being measured. As atmospheric pressure changes, the height of the column rises or falls accordingly. It also refers to a unit of pressure, such as inches of mercury or millimeters of mercury, which is the pressure exerted by a column of mercury of a specific height.
Mercury vapour – It is the gaseous state of mercury, which is a toxic, invisible, and odourless substance that can be produced at room temperature. It is formed when liquid mercury evaporates, and its properties are harnessed in applications like high-intensity mercury-vapour lamps.
Mercury vapour lamp – It is a lamp which generates light from a discharge struck in mercury vapour. It has formerly been widely used in outdoor lighting, now replaced by lamps with better efficacy.
Mercury vapour pressure – It refers to the pressure exerted by mercury vapour in a contained space, which is relevant in the context of ultra-high-pressure mercury vapour lamps which utilize materials with low coefficients of thermal expansion to maintain stability and performance under thermal cycling.
Mergers and acquisitions (M&A) – These are the general terms which are used for the consolidation of organizations or the assets. The terms ‘merger’ and ‘acquisition’ are used as though they are synonymous, but both of these terms mean slightly different things. Mergers and acquisitions are complex and involve many parties. They involve many issues which include (i) corporate governance, (ii) form of payment, (iii) legal issues, (iv) contractual issues, and (v) regulatory approvals. Merger and acquisition also need application of the valuation tools for the evaluation of the mergers and acquisition decision. A merger happens when two organizations, frequently of about the same size, agree to go forward as a single new organization rather than remain separately owned and operated. In case of an acquisition there is a take-over of one organization by another organization in which no new organization is formed. From a legal point of view the organization which has been taken over ceases to exist and the buyer organization swallows the total operations of the taken over organization.
Meridional plane – It is a plane that passes through the central axis of a system, such as a lens or a turbine. It is used to describe an object’s symmetry and is defined differently depending on the field. In optics, it is the plane containing the chief ray and the optical axis. In fluid mechanics, it is a vertical plane which passes through the object’s longitudinal axis.
Meridional ray – It is a light ray which travels in a plane containing the axis of an optical system, such as an optical fibre or a lens, and it crosses the axis at each pass. In the context of fibre optics, this means the ray remains in a single plane and always passes through the core’s axis, unlike a skew ray which travels on a helical path and does not intersect the axis.
Merwinite – It is a mineral which forms at high temperatures during the thermal metamorphism of carbonate rocks, along with spurrite and larnite, under specific pressure and temperature conditions.
Mesh – It is a measurement of particle size frequently used in determining the particle-size distribution of a granular material. Several standardized mesh series have been established. Several mesh sizes have been historically given in the number of holes per inch; because of the width of the wires in the mesh, mesh numbers do not correspond directly to fractional inch sizes, and several different systems standardized with slightly different mesh sizes for the same mesh numbers. It is also called mesh size. It is also the screen number on the finest screen of a specified standard screen scale through which almost all of the particles of a powder sample are going to pass. Available sieve sizes are normally regulated by standards. Those in common use are ISO 565:1990 and ISO 3310-1:2000 standards.
Mesh analysis – It is a strategy for solution of the voltage distribution in some types of electrical networks.
Mesh-belt conveyor furnace – It is a continuously operating furnace which uses a conveyor belt for the transport of the charge.
Meshed network – It is a network where devices (nodes) connect and communicate with each other in a decentralized, peer-to-peer manner, creating multiple paths for data to travel. If one node fails, the network can automatically reroute data through other nodes, ensuring reliability and eliminating single points of failure. This allows for more extensive coverage and stability compared to traditional networks.
Mesh networking – It is a topology where infrastructure nodes connect to other nodes such as to convey information.
Mesh number – It is the number of screen openings per linear inch of the screen. It is also called mash size. Mesh number is also the screen number of the finest screen through which all of the particles of a given powder pass.
Mesh screen – It is a barrier made of inter-woven strands of material like metal or fibre, with a grid of spaces which can block larger objects while allowing air, light, or smaller particles to pass through. The term ‘mesh’ can also refer to the number of openings per linear inch or a specific grading of particle size, with a higher mesh number indicating smaller openings and smaller particle separation.
Mesh size – It is the width of the aperture in a cloth or wire screen.
Mesophase – It is an intermediate phase in the formation of carbon from a pitch precursor. This is a liquid crystal phase in the form of micro-spheres, which, upon prolonged heating above 400 deg C, coalesce, solidify, and form regions of extended order. Heating to above 2,000 deg C leads to the formation of graphite structure.
Mesoporous electrode – It is a type of electrode built from a nano-material with a network of interconnected pores between 2 nano-meters and 50 nano-meters in diameter. These materials are used to improve electro-chemical reactions because of their high surface area and ability to facilitate the transport of ions and electrons into the pore structure. This structure is created using templates, such as surfactants, which are removed after the electrode material is formed, leaving behind the ordered pore network.
Mesoporous oxide film – It is a thin film of a metal oxide which contains a network of interconnected pores within the meso-porous size range of 2 nano-meters and 50 nano-meters in diameter. These films have a high surface area and a uniform, organized pore structure which can be controlled through synthesis methods like sol-gel and self-assembly. Their unique properties make them useful for applications such as catalysis, separation membranes, and sensors.
Mesoscale – It refers to an intermediate length scale between the atomic (microscopic) and macroscopic levels, where phenomena arise which are not simply an average of atomic properties. It is used to study complex systems, such as the behaviour of particles in a material, the properties of mesoscopic devices, or the scale of large weather patterns. Mesoscale engineering frequently involves modeling techniques to bridge the gap between these different scales for applications in several fields.
Mesoscopic – It is pertaining to the size range between microscopic and macroscopic.
Mesoscopic scale – It is an intermediate range between the microscopic (atomic) and macroscopic scales, typically from around 2 nanometers to 1 micrometer, where the behaviour of materials is influenced by both the properties of their constituent particles and the larger structure. This scale is crucial for modeling complex systems by focusing on the collective, average behaviour of groups of particles or meso-domains to bridge the gap between fundamental micro-level physics and macro-level performance.
Metadata – It is the descriptive data about the material for which data are reported. Metadata include a complete description of the material (producer, heat number, grade, and temper etc.), a complete description of the test method, and information about the test plan.
Meta-dynamic recrystallization – It is the recrystallization which occurs during the cooling phase of a hot-working process or between successive passes. It occurs at strains higher than critical strain. It is observed to be a strong function of strain rate and a very weak function of temperature and strain.
Metadyne -m It is a direct current electric machine with crossed fields and two sets of brushes, used as an amplifier or rotary direct current transformer.
Metakaolin – It is a highly reactive, pozzolanic material made by heating kaolin clay between 650 deg C to 800 deg C. This process, called calcination, transforms the crystalline structure of kaolinite into an amorphous, fine white powder. When added to concrete, metakaolin reacts with calcium hydroxide to produce more calcium silicate hydrate (C-S-H) gel, which increases strength, durability, and reduces permeability.
Metakaolin mortar – It is a type of mortar which uses metakaolin, a manufactured pozzolanic material derived from heated kaolin clay, as a binder or admixture to improve its strength, durability, and other properties. This improved mortar can be used in different applications, including high-performance concrete, and it offers benefits like increased compressive strength, reduced permeability, and better resistance to chemical attack compared to conventional mortars.
Metal – It is an opaque lustrous elemental chemical substance which is a good conductor of heat and electricity and, when polished, a good reflector of light. Majority of the elemental metals are malleable and ductile and are, in general, denser than the other elemental substances. As to structure, metals can be distinguished from non-metals by their atomic binding and electron availability. Metallic atoms tend to lose electrons from the outer shells, the positive ions hence formed being held together by the electron gas produced by the separation. The ability of these ‘free electrons’ to carry an electric current, and the fact that this ability decreases as temperature increases, establish the prime distinctions of a metallic solid. From a chemical viewpoint, metal is an elemental substance whose hydroxide is alkaline. It is also an alloy.
Metal alloy – It is a mixture of chemical elements of which in majority of the cases at least one is a metallic element, although it is also sometimes used for mixtures of elements. Majority of the metallic alloys are metallic and show good electrical conductivity, ductility, opacity, and lustre, and can have properties which differ from those of the pure elements such as increased strength or hardness. In some cases, an alloy can reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties such as corrosion resistance or mechanical strength.
Metal amine – It refers to a complex formed between aliphatic amines and metal surfaces, where the amine acts as a corrosion inhibitor by chemically adsorbing onto the metal. The interaction involves the nitrogen atom in the amino group serving as a reaction center, contributing to the reduction of corrosion rates through Lewis-acid-base bonding with the metal.
Metal arc cutting – It consists of a group of arc-cutting processes which severs metals by melting them with the heat of an arc between a metal electrode and the base metal.
Metal arc welding – It consists of a group of arc welding processes in which metals are fused together using the heat of an arc between a metal electrode and the work. Use of the specific process name is preferred.
Metal atom – It is an atom of an element which readily loses electrons to form positive ions (cations). These atoms typically have a small number of valence electrons, are arranged in a three-dimensional crystalline structure, and are held together by metallic bonding, where a ‘sea’ of shared, delocalized electrons surrounds a lattice of positive metal ions.
Metal-based catalyst – It is a substance containing a metal which accelerates a chemical reaction by providing an alternative pathway with a lower activation energy. These catalysts are not consumed during the reaction and work by providing active sites for reactants to interact, often supported on materials like oxides to improve performance and stability. Examples include noble and transition metals like platinum, palladium, nickel, and iron.
Metal carbide – It is normally described as a compound composed of carbon and a metal.
Metal carbonates – It is a chemical compound composed of a metal cation and the carbonate anion [(CO3)2-]. They are typically basic in nature and react with acids to produce a salt, water, and carbon dioxide. They are added as an ingredient for the coating for welding electrode to adjust the basicity of the slag and to provide a reducing atmosphere.
Metal casting – It is a manufacturing process where molten metal is poured into a mould to create a solidified object of a desired shape. The metal cools and hardens within the mould, taking the form of the cavity, which is the negative impression of the final part. This versatile and cost-effective method allows for the creation of complex shapes which are difficult or expensive to produce using other methods, and is widely used across different industries.
Metal casting process – It is the simplest and most direct route to a near net shape product and frequently the least expensive process. This process in its fundamental form needs a mould cavity of the desired shape and liquid metal to pour into the mould cavity. Metal castings are being produced most frequently by pouring of liquid metal into moulds made of sand. The basic components of a mould cavity are cope, drag, parting line, riser, sprue (a channel through which the liquid metal is poured into a mould), and pouring basin etc., as well as the liquid metal handling system known as a ladle. The casting process begins with the making of a mould, which is the ‘reverse’ shape of the part which is to be cast. The mould is made from a refractory material, for example, sand. The metal is heated in a furnace until it melts, and then the liquid metal is poured into the mould cavity. The liquid takes the shape of cavity, which is the shape of the part. It is cooled until it solidifies. Finally, the solidified metal part is removed from the mould.
Metal chloride – It is a chemical compound formed when a metal atom combines with one or more chlorine atoms. These compounds are typically ionic salts, though some can be covalent. They are used in chemical synthesis and can have a wide range of properties, with some being highly soluble in water (like NaCl) and others insoluble (like AgCl).
Metal cleaning – It is the process of removing foreign matter, contaminants, and soils from the surface of metal parts to prepare them for other operations like painting, welding, or to restore their appearance. These contaminants can include oils, greases, rust, scale, tarnish, and manufacturing residues, and their removal is important for the quality and functionality of the metal. Methods range from simple washing with soap and water to industrial processes involving chemical treatments, high-pressure jets, or lasers.
Metal coated steels – These steels are defined as steel substrates coated with a layer of zinc, zinc / aluminum alloy, zinc / silicon alloy, pure aluminum, lead / tin alloy. tin, or chromium etc. Metal coatings of steels improve the life and the performance of the steels. They provide the most effective and economical way of protecting steels against corrosion. Metal coated steels offer unique combination of properties which include high strength, formability, light weight, corrosion resistance, aesthetics, recyclability and low cost.
Metal commodity – It is a raw, basic metal which is traded on global markets in bulk and is valued for its industrial or investment purposes. These are ‘hard’ commodities extracted or mined from the earth and are interchangeable with other units of the same metal, regardless of the producer. They are categorized as either precious metals like gold and silver, or base metals such as copper, aluminum, and zinc, which are used in manufacturing.
Metal-composite laminate – It is a structural material made by bonding together layers of thin metal sheets with layers of fibre-reinforced composite material, like glass, carbon, or aramid fibres, to create a new material with superior properties. This layered structure leverages the strengths of both materials, resulting in a combination that is lighter, stronger, and more fatigue-resistant than monolithic metals, with better impact strength than composites alone. A prominent example is ‘glass reinforced aluminum laminate’.
Metal cored electrode – It is a composite filler metal welding electrode which is consisting of a metal tube or other hollow configuration containing alloying ingredients. Minor quantities of ingredients facilitate arc stabilization and fluxing of oxides. External shielding gas may or may not be used.
Metal cutting – It is the process of removing unwanted material from a metal work-piece to achieve a specific shape, size, and finish. It involves using cutting tools, whether mechanical or thermal, to shape the metal, frequently by separating the material in the form of chips. Common methods include traditional machining like milling and turning, as well as thermal processes like plasma and oxy-fuel cutting, and modern techniques such as water-jet cutting.
Metal cutting processes – These are the processes in which removing of metal generates a new shape, Example are sawing, turning, milling, and broaching.
Metal deactivators, metal deactivating agents (MDA) – These are fuel additives and oil additives which are used to stabilize fluids by deactivating (normally by sequestering) metal ions, mostly introduced by the action of naturally occurring acids in the fuel and acids generated in lubricants by oxidative processes with the metallic parts of the systems. Metal deactivators inhibit the catalytic effects of such ions, retarding the formation of gummy residues.
Metal deformation – it is the change in the shape or dimensions of a metal due to applied forces. There are two main types namely elastic deformation, which is temporary and self-reversing, and plastic deformation, which is permanent. Plastic deformation is a key process for forming metals into useful shapes through methods like forging, rolling, and extrusion.
Metal detection system – It is an integrated system which is designed to detect metal objects on the conveyor belt. Regular inspections and calibrations are necessary for accurate performance and system integrity.
Metal diaphragm – It is a thin, circular plate of metal used in many applications, such as sealing and pressure measurement, which can deform elastically under pressure to perform functions like isolating fluids, regulating pressure, or converting movement into a measurable signal. These diaphragms are frequently made from materials like stainless steel or other alloys and are known for their durability, resistance to high temperatures and corrosive environments, and accuracy in devices like pressure transducers and pumps.
Metal disk – It is a flat, circular object made of metal, which can be a rigid component in technology like a hard drive platter or a spinning part in a machine. The term is used in several different contexts, from computer storage to mechanical engineering and everyday objects.
Metal displacement – It is a chemical reaction where a more reactive metal replaces a less reactive metal from its salt solution. This process, also known as a single displacement or replacement reaction, involves a redox reaction where the more reactive metal gives up electrons to the metal ion in the solution, forming a new compound and causing the less reactive metal to be deposited as a solid. A common example is placing an iron nail into a copper sulphate solution, where the iron displaces the copper.
Metal dusting – It consists of accelerated deterioration of metals in carbonaceous gases at high temperatures to form a dust-like corrosion product.
Metal electrode – It is an electrode used in arc welding or cutting which consists of a metal wire or rod that is either bare or covered with a suitable covering or coating.
Metal encapsulation – It refers to the process of enclosing metal nano-particles within a porous material, such as zeolite, to improve their catalytic activity and selectivity for chemical reactions. This technique allows for improved mass transfer and protection of the metal from poisoning, hence promoting higher reaction efficiency.
Metal extraction – It is the process of separating and purifying metals from their ores, which involves several steps like crushing, concentration, reduction, and refining. The specific methods used depend on the metal’s reactivity and the ore’s composition, utilizing techniques such as smelting, electrolysis, or chemical reactions.
Metal extrusion – It is a manufacturing process which forces a metal billet through a die with a specific cross-sectional shape under high pressure. This process reduces the metal’s cross-section and creates products with a uniform shape, such as bars, tubes, and complex profiles. The metal can be extruded while either hot or cold, depending on the material and desired outcome.
Metal fabrication – It is the process of creating products or structures from metal by cutting, bending, and assembling it. It is a value-added process that transforms raw metal materials into a finished product through a series of steps like design, cutting, forming, welding, and finishing.
Metal fibre – It is a synthetic, thin filament made from a metal, metal alloy, or a material with a metal core or coating. These fibres are known for their electrical conductivity, high strength, and durability, making them useful in applications ranging from textiles for decorative or conductive purposes to reinforcement in concrete and advanced electronics.
Metal film resistor – It is a passive electrical component which uses a thin, resistive metal or metal alloy layer coated onto a cylindrical insulating substrate, like a ceramic rod, to limit the flow of current. This type of resistor is known for its stability, accuracy, and low temperature coefficient, making it ideal for precision applications like active filters and timing circuits. The desired resistance value is precisely adjusted by cutting a helical groove into the metal film, which effectively lengthens the resistive path.
Metal filter – It is a metal structure having controlled interconnected porosity produced to meet filtration or permeability requirements.
Metal finishing – It refers to the processes involved in treating metal surfaces to improve their properties, frequently resulting in the production of metal-bearing sludge because of the chemical waste treatment methods such as the reduction of chromates and precipitation of heavy metals.
Metal flow – It refers to the movement and deformation of metal during manufacturing processes like forging, casting, or forming. It describes how the metal’s internal structure changes under stress, taking on a new shape as it fills a mould or die. Metal flow is the macroscopic movement of metal as it undergoes plastic deformation. This movement is influenced by several factors such as tool geometry, material properties, and process parameters.
Metal flow velocity – It is the speed at which metal moves through a process like extrusion or casting. It is a critical factor in manufacturing, as it affects the quality of the final product, with ideal velocities preventing defects like turbulence or premature solidification. Factors like extrusion speed, billet temperature, and die temperature all influence the metal’s flow velocity.
Metal foam – It is a lightweight, cellular material made of solid metal with a large volume of gas-filled pores, typically consisting of only 5 % to 25 % metal. It can be in either an open-cell structure, where the pores are interconnected, or a closed-cell structure, where the pores are sealed. This high porosity gives it unique properties like low density, high strength-to-weight ratio, and good energy absorption capabilities.
Metal forging – It is a deformation process where metal is pressed, pounded or squeezed under great pressure into high strength parts known as metal forgings. The forging process is entirely different from the casting (or foundry) process, as metal used to make forged parts is neither melted nor poured as in the casting process.
Metal forming – It is a manufacturing process which shapes metal by applying force to plastically deform it into a desired form without adding or removing material. This is achieved through processes like forging, rolling, extrusion, and bending, which permanently alter the metal’s shape and size.
Metal forming processes – The term metal forming refers to a group of manufacturing processes by which the given material, normally shapeless or of a simple geometry, is transformed into a useful part without change in the mass or composition of the material. This part normally has a complex geometry with well-defined (i) shape, (ii) size, (iii) accuracy and tolerances, (iv) appearance, and (v) properties. Metal forming processes are primary shaping processes in which a mass of metal or alloy is subjected to mechanical forces. Under the action of such forces, the shape and size of metal piece undergo a change. By mechanical working processes, the given shape and size of a machine part can be achieved with high economy in material and time. These processes consist of deformation processes in which a metal work-piece (billet, bloom, or blank) is shaped by tools or dies. The design and control of such processes depend on the characteristics of the material of the work piece, the requirements of the finished product, the conditions at the interface of the tool and the work piece, the mechanics of plastic deformation (metal flow), and the equipment used. These factors influence the selection of geometry and material of the tool as well as processing conditions (examples are temperatures of die and work piece and lubrication). Since several of the metalworking operations are rather complex, models of different types, such as analytical, physical, or numerical models, are frequently used to design these processes.
Metal fume fever – It is a self-limiting, flu-like illness caused by inhaling metal oxide fumes, most commonly zinc oxide from welding galvanized metal. Symptoms such as fever, chills, and muscle aches typically appear a few hours after exposure and resolve within 12 hours to 48 hours after exposure stops. Diagnosis is difficult since symptoms mimic the flu, so an occupational history is important. Supportive care like rest, fever reducers, and analgesics is the main treatment, but preventing exposure is the key.
Metal fumes – These are tiny, airborne particles of metal oxides that form when metals are heated to a vapor and then condense in the air. They are created during processes like welding, cutting, and smelting and can be toxic if inhaled, causing acute symptoms like flu-like metal fume fever or chronic health problems such as lung damage.
Metal gasket – It is a sealing component made entirely from metal, designed for high-pressure and high-temperature applications where non-metallic gaskets are unsuitable. It is also known as metallic or ring-type joint (RTJ) gaskets, they are robust, manufactured from materials like stainless steel or Inconel, and are often fitted into grooves machined into the flanges they are sealing.
Metal gate – It refers to a type of gate structure used in multiple-gate devices which is necessary for tuning the threshold voltage in undoped or lightly doped channels, enabling improved circuit performance and reducing variations because of the dopant fluctuations. It also refers to a physical structure for security and access, like a fence opening made of materials like iron, steel, or aluminum.
Metal gate electrode – It is a metal component in a MOSFET (metal-oxide-semiconductor field-effect transistor) which controls the flow of current between the source and drain by creating an electric field across a gate dielectric. It replaces older poly-silicon gates in modern transistors to improve performance, simplify manufacturing, and allow for tuning of the transistor’s threshold voltage, especially with high-k dielectrics.
Metal hydride-hydrogen system – It is a technology which uses a reversible chemical reaction between hydrogen gas and a metal or alloy to store hydrogen safely and compactly in a solid state. The system absorbs hydrogen under specific temperature and pressure conditions, forming a metal hydride, and releases it when heated. This process offers a safer and more volumetric-efficient alternative to storing hydrogen as a high-pressure gas or liquid.
Metal-induced embrittlement (MIE) – It is the embrittlement caused by diffusion of metal, either solid or liquid, into the base material. Metal induced embrittlement occurs when metals are in contact with low-melting point metals while under tensile stress. The embrittler can be either solid metal-induced embrittlement (SMIE) or liquid metal-induced embrittlement (liquid metal embrittlement). Under sufficient tensile stress, metal-induced embrittlement failure occurs instantaneously at temperatures just above melting point. For temperatures below the melting temperature of the embrittler, solid-state diffusion is the main transport mechanism. This occurs in the several ways such as (i) diffusion through grain boundaries near the crack of matrix, (ii) diffusion of first monolayer heterogeneous surface embrittler atoms, (iii) second monolayer heterogenous surface diffusion of embrittler, and (iv) surface diffusion of the embrittler over a layer of embrittler. The main mechanism of transport for solid metal-induced embrittlement is surface self-diffusion of the embrittler over a layer of embrittler that’s thick enough to be characterized as self-diffusion at the crack tip. In comparison, liquid metal-induced embrittlement dominant mechanism is bulk liquid flow that penetrates at the tips of cracks.
Metal injection moulding (MIM) – It is a metal-working process in which finely-powdered metal is mixed with binder material (40 % polymer) to create a ‘feedstock’ which is then shaped and solidified using injection moulding. The part is removed from the mould, the binder is removed using either solvent extraction or thermal processes, and the part is sintered to decrease porosity. Metal injection moulding combines the most useful characteristics of powder metallurgy and plastic injection moulding to facilitate the production of small, complex-shaped metal components with outstanding mechanical properties. The moulding process allows high volume, complex parts to be shaped in a single step. After moulding, the part undergoes conditioning operations to remove the binder (debinding) and densify the powders. Finished products are small components used in several industries and applications.
Metal insert – It is a component made of a harder material, frequently a metal, which is embedded into a softer material like plastic to improve strength, durability, and functionality. These inserts are used to create strong, permanent connections and can provide features like threads or other specific properties. In manufacturing, inserts are frequently installed during moulding processes, which is known as insert moulding.
Metal-insulator-metal structure – It is a device architecture with a thin insulating layer sandwiched between two layers of metal. This configuration is used in applications like capacitors, which exploit the structure to achieve high capacitance per unit area, or in diodes and metamaterials, which utilize the electrical and optical properties of the layers.
Metal-insulator-semi-conductor capacitor – It is a two-terminal electronic component consisting of a metal electrode, a semi-conductor layer, and an insulating layer separating them. It functions as a capacitor and is a fundamental building block for several semi-conductor devices, particularly field-effect transistors, where the semi-conductor’s surface properties can be controlled by applying a voltage to the metal gate. The term is frequently used interchangeably with ‘metal-oxide-semi-conductor’ capacitor, especially when the insulator is silicon di-oxide, but metal-insulator-semi-conductor is a broader term that applies to any di-electric material.
Metal ion absorption – It is the process by which metal ions are retained by another substance, either by binding to its surface (adsorption) or by being taken into its bulk volume (absorption). The term is frequently used in contexts like water filtration, where materials like nano-fibres capture metal ions from waste-water. The mechanism can be either physical (weak interactions like Van der Waals forces) or chemical (stronger chemical bonds).
Metal layer – It refers to a sheet of metal used in building construction or, more commonly in technology, a deposited layer of metal used for connections in microchips. In integrated circuit (IC) fabrication, multiple metal layers are stacked and used to connect components like transistors, with lower layers typically handling shorter, more localized connections and higher layers handling longer, higher-power connections like clocks. In construction, a metal layer is a sheet of metal, frequently steel or aluminum, used for roofing or other building elements.
Metallic adherends – These are metal surfaces which are prepared to be joined to another material using an adhesive. These surfaces need specific cleaning and treatment to create a strong and durable bond, which can include surface roughening for mechanical interlocking or the application of primers for chemical adhesion.
Metallic aluminum – It is a pure, silvery-white, lightweight metal that is extracted from bauxite ore. It is known for being strong, corrosion-resistant, and an excellent conductor of both heat and electricity. Since it is highly reactive, metallic aluminum does not occur naturally and is produced industrially through processes like the Hall-Heroult electrolytic process.
Metallic bond – It is the principal bond between metal atoms, which arises from the increased spatial extension of valence-electron wave functions when an aggregate of metal atoms is brought close together. An example is the bond formed between base metals and filler metals in all welding processes.
Metallic bonding – It is a type of chemical bonding that arises from the electrostatic attractive force between conduction electrons (in the form of an electron cloud of delocalized electrons) and positively charged metal ions. It can be described as the sharing of free electrons among a structure of positively charged ions (cations). Metallic bonding accounts for several physical properties of metals, such as strength, ductility, thermal and electrical resistivity and conductivity, opacity, and lustre.
Metallic carbonates – They are chemical compounds composed of a metal cation and the carbonate anion [(CO3)2-]. They are typically basic in nature and react with acids to produce a salt, water, and carbon di-oxide.
Metallic chlorides – These are chemical compounds formed by the combination of a metal and chlorine. They are characterized by the presence of a metal cation bonded to one or more chloride anions. These compounds can be ionic or covalent, depending on the metal involved and the specific conditions.
Metallic coating – It is a layer of metal applied to a surface, known as a substrate, to improve its performance, durability, or appearance. These coatings can provide corrosion resistance, improve hardness, and offer a decorative finish. Examples include galvanizing steel with zinc and electroplating with nickel or chromium.
Metallic component – It is a part made from metal or a metal alloy, designed to perform a specific function in a larger system. These components are valued for properties like strength, conductivity, and durability and are used in everything from structural elements to electrical wiring.
Metallic contact – It refers to the direct physical interface between two metallic surfaces, or the interaction between a metal and another material. This contact can facilitate the flow of electrons in conductors or create junctions with specific electrical properties, such as an ohmic contact or a Schottky contact. The nature of the contact depends on the materials involved and their properties.
Metallic corrosion – It is the natural process where a refined metal degrades because of the chemical or electro-chemical reactions with its environment, such as air and moisture. This reaction converts the metal into more stable compounds like oxides, hydroxides, or sulphates, leading to the deterioration of the metal’s properties like strength and lustre. The most common example is the rusting of iron.
Metallic fibre – It is manufactured fibre which is composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal.
Metallic gaskets – These gaskets can be fabricated in a variety of shapes and sizes recommended for use in high pressure / temperature applications. These gaskets need a much higher quality of the sealing surface than non-metallic gaskets. Except for weld ring gaskets, high loads are needed to seat metallic gaskets, since they rely on the deformation or coining of the material into the flange surfaces. Examples are ring type joints, lens rings, weld rings, and solid metal gaskets etc.
Metallic glass – It is a non-crystalline metal or alloy, normally produced by drastic supercooling of a molten alloy, by molecular deposition, which involves growth from the vapour phase (e.g., thermal evaporation and sputtering) or from a liquid phase (e.g., electroless deposition and electro-deposition), or by external action techniques (e.g., ion implantation and ion beam mixing).
Metallic inclusion – Metallic inclusions are defects within metallic materials, which can consist of foreign metallic particles and which negatively impact mechanical properties such as strength, machinability and facilitate corrosion.
Metallic interconnectors – These are materials used to recover and transfer electrons between cells, preferred for applications below 750 deg C because of their lower costs, higher electric and thermal conductivity, and reduced sensitivity to thermal stresses. Common choices include ferritic steels and chromium-based alloys, although challenges exist in achieving good contact with ceramic components and managing oxide layer formation.
Metallic iron – It is a form of the element iron (Fe) which is pure enough to be used as a metal. It is produced by removing oxygen from iron ore, which is a mineral substance, and can be used as a reducing agent or alloyed with other elements to create steel. Unlike the iron found in most rocks, which is in the form of iron oxides, metallic iron exists in a state which can be shaped and used for different purposes.
Metallic membrane – It is a thin layer of metal, frequently palladium or a stainless-steel alloy, used for separating gases like hydrogen from mixtures. It functions by selectively allowing hydrogen to pass through its lattice while blocking other gases. These membranes are characterized by high selectivity and thermal stability, but can be limited by cost and susceptibility to contaminants.
Metallic membrane couplings – In general, the flexibility of these couplings is obtained from the flexing of thin metallic disks or diaphragms.
Metallic nano-particles – These are nano-scale particles, typically between 1 nano-meter and 100 nano-meters, composed of metals like gold, silver, or platinum. Because of their small size, they possess unique physical, chemical, and optical properties distinct from their bulk counterparts, enabling applications in fields such as electronics, and catalysis.
Metallic oleates – These are salts of oleic acid. They are a common component of oils. Metallic oleates assist in reducing friction in case of mixed and boundary lubrication.
Metallic ore – It is a naturally occurring rock or mineral from which a metal can be extracted profitably. To be considered an ore, a mineral is required to contain a metal and the process of extracting that metal is to be both economically viable and convenient, meaning the cost of extraction is less than the value of the metal recovered.
Metallic oxalates – These are insoluble salts formed by the chemical reaction between a metal cation and the oxalate anion [(C2O4)2-]. These compounds are frequently found as alteration products on different materials like stone, wood, and paintings.
Metallic oxide – It is a chemical compound formed when a metal reacts with oxygen. These oxides are typically characterized by being ionic compounds, though some can show covalent bonding. They are normally insoluble in water, but some, like aluminum oxide, can dissolve. A key characteristic is their basic nature; they react with acids to form salts and water.
Metallic phosphates – These are compounds formed by the chemical combination of a metal and phosphate ions [(PO4)3-]. They are a diverse class of materials with applications ranging from catalysts to energy storage uses. These materials show a range of structural and chemical properties depending on the specific metal and the way the phosphate groups are bonded.
Metallic powder – It is metal which has been broken down into very fine particles, ranging in size from micro-meters to a few hundred micro-meters. It is a raw material for several manufacturing processes, most notably powder metallurgy and additive manufacturing, used to create a wide range of products from gears to complex 3D-printed parts.
Metallic salt – It is an ionic compound formed when a metal replaces the hydrogen in an acid. It consists of a positively charged metal cation and a negatively charged anion, held together by electrostatic forces. Examples include sodium chloride (NaCl) and copper sulphate (CuSO4).
Metallic scaffold – It is a temporary structure made of metal components, like steel or aluminum, used to support workers and materials during construction or maintenance of buildings and other large structures.
Metallic silver – It can be defined as the physical element silver (Ag), known for its shiny, metallic appearance and high conductivity, or as a colour, which is a shiny, light shade of gray that resembles the metal. The term ‘metallic’ means ‘of, relating to, or being a metal’.
Metallic stearates – These are compounds of long-chain fatty acids with metals of different valencies; some metallic stearates are not soluble in water, whereas other stearates, i.e. compounds of long-chain fatty acids with alkaline metals or ammonia are soluble in water. The most important metallic stearates, in terms of number of applications and quantities produced, are the metallic stearates of calcium, zinc, magnesium and aluminium. Metallic stearates have manifold range of use. The most important properties of metallic stearates are lubricating properties, separating properties, water repellence, gelling capacity, stabilizing effect, foam inhibition, and acid scavenger.
Metallic structure – It is the arrangement of atoms in a metal, where positive metal ions form a lattice surrounded by a ‘sea’ of delocalized electrons. This structure, held together by strong metallic bonds, results in properties like high melting points, conductivity, malleability, and ductility. The specific way the atoms are arranged can vary (e.g., body-centered cubic or face-centered cubic), influencing the metal’s properties.
Metallic substance – It is a material which shows characteristics like a shiny appearance, good electrical and heat conductivity, and malleability because of its chemical bonding structure, known as the sea of electrons. These substances can be pure elements, such as gold or iron, or alloys, which are mixtures like brass or steel.
Metallic sulphates – These are compounds formed when a metal combines with the sulphate ion [(SO4)2-)]. They are typically salts of sulphuric acid (H2SO4) and are formed by replacing the hydrogen atoms of sulphuric acid with a metal. These compounds show diverse structures and properties depending on the specific metal involved.
Metallic sulphides – These are chemical compounds formed when one or more metallic elements combine with sulfur. These compounds are characterized by the presence of a sulphide ion (S2-) and a metallic cation. They are normally found as minerals and play a important role in several industries.
Metallic system – It refers to a group of metallic substances, such as an alloy, used to achieve specific properties. Metallic systems refer to inorganic substances which are mainly composed of metallic elements and can include small quantities of non-metallic elements, frequently used in the form of alloys to achieve desired physical and mechanical properties. These systems are important in different applications because of their strength and specific mechanical characteristics.
Metallic thin film – It is a very thin layer of metal, typically from fractions of a nano-meter to several micro-meters thick, deposited onto a substrate using physical, chemical, or other processes. These films are used in a wide variety of applications because of their unique properties, such as high electrical and thermal conductivity, optical reflectance, and mechanical strength. Examples include aluminum on glass for mirrors and copper in advanced computer chips.
Metallic wear – Typically, it is the wear because of the rubbing or sliding contact between metallic materials which shows the characteristics of severe wear, e.g., considerable plastic deformation, material transfer, and indications that cold welding of asperities possibly has taken place as part of the wear process.
Metallic wire – It is a long, thin, flexible conductor made of metal, such as copper or aluminum. It is used to transmit electricity or telecommunications signals, or for mechanical loads. The metal is typically drawn through a die to form a cylindrical shape, and it can be coated to prevent corrosion.
Metalliferous ore – It is a natural rock or mineral deposit containing valuable metals which can be extracted economically. These ores need processing to separate the valuable metal from the other materials (gangue). Examples of metalliferous ores include iron ore for making iron and steel and deposits rich in copper, gold, or silver.
Metal line – It is the level of molten metal in a melting or smelting furnace.
Metallization – It is a measure of the conversion of iron oxides into metallic iron (either free, or in combination with carbon as cementite) by removal of oxygen due to the action of the reductant used. Degree of metallization refers to that portion of the total iron present as metallic iron and is given by the equation ‘Degree of metallization = (weight of metallic iron/weight of total iron) x 100 = (Fe M/Fe T) x 100’.
Metallizing – It is the application of an electrically conductive metallic layer to the surface of another material. It is also the application of metallic coatings by non-electrolytic procedures such as spraying of molten metal and deposition from the vapour phase. Zinc wire or powder is applied to an abrasive blast cleaned steel surface through a gas flame which melts the zinc. Metalizing is forming a metallic coating by atomized spraying with molten zinc or by vacuum deposition. It is also called spray metalizing. Metalizing is used to repair large damaged areas of galvanized coating.
Metallograph – It is an optical instrument designed for visual observation and photo-micrography of prepared surfaces of opaque materials at magnifications of 25x to around 2,000×. The instrument consists of a high-intensity illuminating source, a microscope, and a camera bellows. On some instruments, provisions are made for examination of the sample surfaces using polarized light, phase contrast, oblique illumination, dark-field illumination, and bright-field illumination.
Metallographical microscope observation (MMO) – This is the traditional method in which two-dimensional slices through steel samples, are examined with an optical microscope and quantified by the eye. In it, the results are evaluated using charts such as the JK reference scale. This technique is only suitable for qualifying inclusions between 2 microns to 15 microns and is limited to very small sample sizes. This method does not provide any data on the chemical composition of inclusions. Problems arise when interpreting slices through complex-shaped inclusions. Although there are some methods to relate two-dimensional results to three-dimensional reality, this is generally very problematic.
Metallographic analysis – It is the study of the microstructure of metals and alloys, often using microscopy, to understand their properties and behavior. It involves preparing samples, frequently by sectioning, mounting, grinding, polishing, and etching, to reveal their microstructure for examination under a microscope. This analysis helps in understanding the material’s grain size, crystal structure, phase distribution, and presence of defects like cracks or inclusions, which in turn relates to its mechanical properties.
Metallographic examination – It is also called metallography. It is the study of the physical structure and components of metals and alloys through microscopic analysis. This destructive testing method involves preparing a polished and etched sample to reveal its microstructure, such as grain size, phases, and inclusions, in order to understand its properties like strength, hardness, and ductility.
Metallographic method – It is a technique for studying the micro-structure of metals and alloys by preparing and examining a prepared surface using microscopy. This involves a series of steps including sectioning, mounting, grinding, polishing, and chemically etching the sample to reveal its internal structure, such as grains, grain boundaries, and defects, which are then viewed under a microscope.
Metallography – It is the study of the structure of metals and alloys by different methods, especially by optical and electron microscopy.
Metalloid – It is a chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and non-metals. There is no standard definition of a metalloid and no complete agreement on which elements are metalloids. The six commonly recognized metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Five elements are less frequently so classified are carbon, aluminum, selenium, polonium, and astatine.
Metallo-physical reaction – An example of this is the embrittlement caused by hydrogen which diffuses into steel, possibly leading to failure of a component. Embrittlement can be the result of a careless manufacturing process, e.g. when surface coatings such as electrochemical zinc plating are not applied properly on high-strength steel products (primary embrittlement). It can also be initiated by corrosion processes (metal dissolution). In the latter case, reference is made to corrosion-induced hydrogen assisted cracking (secondary embrittlement).
Metallostatic head – The metallostatic pressure is given by d x g x h, where ‘d’ is the metal density, ’g’ is the acceleration due to gravity, and ‘h’ is the height of liquid metal column above the filling point. A higher metallostatic pressure gives higher velocity of molten metal, and thereby higher fluidity.
Metallostatic pressure – It is the pressure exerted by a column of molten metal in a casting mould because of the gravity. It is a crucial factor in the casting process, influencing the flow of the metal into the mould cavity, the structure of the solidifying surface layer, and the final density of the casting. This pressure is substantial at the moment of pouring and during the shaping process.
Metal lot – It is a master heat which has been approved for casting and given a sequential number by the foundry / steel melting shop. It is a collection of material which shares the same chemical composition, shape, condition, and nominal cross-section dimensions, which has been processed together or in a sequence. This definition is crucial for testing, inspection, and certification, since it ensures that the material is consistent before it is used in a manufacturing process.
Metallo-thermic reduction – it is a chemical process which uses a more reactive metal to reduce a less reactive metal’s compound, such as an oxide, to produce the pure, less reactive metal. Common reactive metals used as reducing agents include aluminum, magnesium, calcium, and silicon. The reaction produces the desired metal and a metal oxide or other compound of the reducing agent, frequently at high temperatures.
Metallo-thermo-mechanics – It is an engineering field which studies the complex interplay between mechanical behaviour, temperature, and the microstructure of metallic materials, particularly during processes like heat treatment, welding, or machining. It focuses on understanding and predicting how these factors influence each other and the resulting material properties.
Metallurgical and material engineering – It is the discipline which applies the knowledge of engineering to study, develop, design and operate processes which transforms raw materials into useful engineering product intended to improve technological advancement in different industrial applications such as aerospace, automobile and other sectors of the industry. This branch of engineering is known as the bed-rock of engineering discipline. It has close links with other engineering branches.
Metallurgical attribute – It is a specific, measurable characteristic of a metal or alloy related to its chemical composition, micro-structure, or physical and mechanical properties. These attributes determine how a metal behaves during processing and how it is going to perform in a specific application.
Metallurgical bond – It is the principal bond which holds metal together and is formed between base metals and filler metals in all welding processes. This is a primary bond arising from the increased spatial extension of the valence electron wave functions when an aggregate of metal atoms is brought close together. It is also referred to as metallic bond. In galvanizing, it is the bonding of iron / zinc inter-metallic layers to the base steel.
Metallurgical burn – It is the modification of the micro-structure near the contact surface because of the frictional temperature rise.
Metallurgical coal – It is the coal which is used for carbonizing in coke oven for the production of metallurgical coke. There are three types of metallurgical coal namely (i) hard coking coal (HCC), (ii) medium coking coal (MCC), and (iii) semi-soft coking coal (SSCC) or weak coking coal. Metallurgical coals are normally classified as high, medium, and low volatile based on their dry, mineral matter free volatile matter (VM). High volatile coals have volatile matter typically between 31 % and 38 %, medium volatile coals have volatile matter between 22% and 31 %, and low volatile coals have volatile matter between 17 % and 22 %. There is normally a strong inverse relation between vitrinite reflectance and dry ash free volatile matter content.
Metallurgical coke – Metallurgical coke is a hard carbon material produced in the process of the ‘destructive distillation’ of different blends of bituminous coal. It is produced by carbonization of coal at high temperatures (1,100 deg C) in an oxygen deficient atmosphere in a coke oven. Coke is essential for the blast furnace iron making process in order to support the burden and provide gas permeability, thus a minimum coke burden limit exists. Coke constitutes a major portion of the production costs of hot metal. Other than economical aspects, coke consumption is also strongly related to the CO2 (carbon di-oxide) emissions and hence to the environmental problems. It is normally low in sulphur, has a very high compressive strength at high temperatures. It is used in metallurgical furnaces not only as fuel, but also to support the weight of the charge.
Metallurgical compatibility – It is a measure of the extent to which materials are mutually soluble in the solid state.
Metallurgical engineering – It is the field which studies the physical and chemical behaviour of metallic elements and their alloys to develop, produce, and process them into useful products. It involves extracting metals from their natural ores, refining them, and altering their properties through processes like alloying to meet specific requirements for various applications, such as in aerospace, electronics, and construction.
Metallurgical evaluation – It is a process which analyzes and assesses the characteristics, structure, and properties of metals and alloys to ensure their suitability for a specific application, determine failure causes, or verify quality. It involves using techniques like microscopy, mechanical testing, and chemical analysis to understand properties such as strength, hardness, ductility, and composition. This evaluation is crucial for quality control, safety assurance, and failure analysis in industries like manufacturing and construction.
Metallurgical events – These refer to the changes in the micro-structure and properties of metals which occur during processes such as hot rolling, influenced by thermal and mechanical conditions applied throughout the operation.
Metallurgical industry – It involves the extraction, processing, refining, and fabrication of metals and alloys from their ores to create products for several applications. It encompasses activities from mining and smelting to producing finished goods like steel, aluminum, and other specialty alloys used in construction, automotive, and electronics industries.
Metallurgical industrial furnaces – These furnaces are used in the metallurgical industry for carrying out different metallurgical processes. Metallurgical furnaces are mostly used for (i) extraction of metals from ores, (ii) calcining and sintering of ores, (iii) melting, refining and alloying of metals, (iv) heating of metals, (v) carbonizing of coals, and (vi) heat treatment of metals etc. Energy sources for metallurgical furnaces are (i) combustion of fossil fuels, such as solid, liquid and gaseous fuels, (ii) electric energy such as resistance heating, induction heating or arc heating, and (iii) chemical energy such as exothermic reactions.
Metallurgically influenced corrosion – It is the corrosion which is caused by the metallurgical factors. These factors include alloy chemistry and heat treatment. The metallurgical influences on corrosion are the relative stability of the components of an alloy, metallic phases, metalloid phases such as carbides, and local variations in composition in a single phase. One example is the ways in which nonmetallic inclusions, such as oxides and sulphides can influence corrosion. Dealloying, selective leaching, and parting are terms used to describe that form of corrosion in which an element is selectively removed from an alloy. Stress corrosion and hydrogen embrittlement are mechanisms which have influence on corrosion. The most common form of metallurgically influenced corrosion is intergranular corrosion. It occurs when corrosion is localized at grain boundaries. Frequently, this localized corrosion leads to the dislodgement of individual grains and a roughening, or sugaring, of the affected surface. It is typified by an apparent increase in the corrosion rate with time.
Metallurgical mechanism – It is a fundamental process which dictates how a metal’s internal structure (micro-structure) changes, such as recrystallization, grain growth, precipitation, or transformation. These mechanisms are how engineers control a metal’s mechanical properties and performance by manipulating its structure through processes like heating, cooling, or forming.
Metallurgical parameter – It is a measurable value used to describe the properties, behaviour, or processing of a metal or alloy, such as hardness, strength, ductility, or electrical conductivity. These parameters are critical for selecting the right materials for a specific application, optimizing manufacturing processes like casting or heat treatment, and predicting performance in industries like mining, and construction.
Metallurgical performance – it refers to the effectiveness and efficiency with which a metal or ore can be processed (e.g., extracted, refined, formed, heat-treated) and the final quality, behaviour, and properties of the resulting metallic material in a specific application. It is a broad concept which encompasses both the performance during manufacturing processes and the material’s performance in its final use.
Metallurgical plant – It is a large-scale industrial facility designed for the extraction and refining of metals from their ores. These plants use different metallurgical processes, such as crushing, grinding, and smelting, to process metallic raw materials into finished products. They typically include storage, process units, administrative buildings, and auxiliary facilities, all arranged according to a specific technological flow designed to minimize cost and maximize efficiency.
Metallurgical slag – It is stony waste by-product created during the high-temperature smelting and refining of metal ores. It is formed when impurities in the ore combine with added fluxes, creating a molten, glassy material that can be separated from the desired metal. This molten slag, which includes a complex mixture of oxides like silicates, oxides of calcium, and magnesium, is a significant industrial solid waste which is frequently recycled for applications such as road construction.
Metallurgical technique – It is a process used to extract, refine, and work with metals and their alloys. These techniques involve the scientific and technological methods for separating metals from their natural ores, purifying them, and then shaping and treating them to create useful objects. Examples include traditional methods like fire assay and advanced techniques like spectroscopy.
Metallurgical test – It consists of studies pertaining to the production, purification and properties of metals and their extraction.
Metallurgist – Metallurgist is a scientist or engineer who specializes in the study of metals, their properties, and their uses. They are experts in the extraction, refining, alloying, and fabrication of metals, working with everything from raw ores to finished metal products.
Metallurgy – It is the science and technology of metals and alloys. Process metallurgy is concerned with the extraction of metals from their ores and with refining of metals. Physical metallurgy deals with the physical and mechanical properties of metals and their alloys affected by composition, processing, and environmental conditions, and mechanical metallurgy is concerned with the response of metals to the applied forces. There are other branches of metallurgy which deals with material testing and analysis, heat treatment, metallography and micro-structures, refractories, composites, energy, nano-metals, metal powders, material characterization, fractures, fractography and failure analysis, tribology, surface engineering, metal joining, and metal forming etc.
Metal-matrix composite – It is a material which consists of a non-metallic reinforcement, such as ceramic fibres or filaments, incorporated into a metallic matrix. Metal-matrix composites are advanced composites which have a non-metallic reinforcement incorporated into a metallic matrix. Reinforcements can constitute from 10 % to 60 % of the composite. Continuous fibre or filament reinforcements include graphite, silicon carbide, boron, alumina, and refractory metals. Matrix materials include aluminum (the most common), titanium, magnesium, copper, and ordered inter-metallic compounds such as nickel-aluminum (NiAl) and titanium aluminum (Ti3Al).
Metal melt – It is the process of heating a solid metal to its melting point, converting it into a liquid state. This molten metal is then used in processes like casting to form new shapes, which is a key step in several manufacturing and metallurgical applications.
Metal mesh – It is a grid-like material made of metal strands or wires which are woven, welded, or expanded to form a net or screen. It is a versatile material, frequently made from metals like stainless steel, aluminum, or copper, and used for a wide range of applications including structural support, barriers, filtering, and decorative elements.
Metal migration – It is the movement of metal ions or atoms, which can be caused by an electric field, high temperatures, or chemical processes. It frequently occurs in electronic systems, where it can lead to circuit failure by forming conductive paths or voids, but also happens in environmental contexts like soil or groundwater. A common type, electrochemical migration, is facilitated by moisture and can cause a metal to dissolve and deposit as a dendrite elsewhere.
Metal moulding – It is a manufacturing process for shaping materials, typically molten metal or powdered metal mixtures, by pouring or injecting them into a mould cavity. This process is used to create complex or simple metal parts by allowing the material to cool and solidify within the mould’s shape, which is then removed to reveal the finished component. Key methods include casting, where molten metal is poured into a mould, and metal injection molding (MIM), which uses a mixture of metal powder and binders that is injected into a mould and then heated to remove the binders and sinter the metal.
Metal nano-crystals – These are metallic particles with at least one dimension between 1 nano-meter and 100 nano-meters, and are defined by their unique size-dependent chemical and physical properties. These nano-crystals show different characteristics from conventional, larger metal crystals because of their high surface area and the large number of grain boundaries relative to their volume. This makes them useful for applications like catalysis.
Metal nano-particles – These are nano-scale particles, typically between 1 nano-meter and 100 nano-meters in size, made of pure metals like gold, silver, or iron. They are defined by their unique physical, chemical, and optical properties that result from their small size and large surface-to-volume ratio, making them useful in fields such as electronics, and environmental remediation.
Metalock – Itis a cold-repair process used to fix cracks and fractures in cast iron, steel, and other metals without welding. The technique, also known as ‘metal stitching’, involves mechanically joining the broken pieces with interlocking, high-strength metal keys. The Metalock process has been developed in the 1930s as a safer alternative to welding in hazardous, flammable environments, such as oil fields.
Metal-organic chemical vapour deposition (MOCVD) – It is a controlled synthesis method that involves vapor phase reactions to grow materials with precise control over precursor ratios, growth time, and growth rate, particularly useful for synthesizing wafer-scale uniform transition metal dichalcogenides (TMDs) in the field of chemistry.
Metal-organic framework – It is a porous, crystalline material made of metal ions or clusters connected by organic molecules, forming a highly structured, sponge-like network. These materials have an extremely high surface area and can be designed for specific applications like gas storage and separation, catalysis. They are a type of material which combines inorganic and organic chemistry, and their properties can be tuned by changing the metal nodes and organic linkers.
Metal oxidation – It is a chemical reaction where a metal reacts with oxygen, causing the metal to lose electrons and form a metal oxide. This process can occur spontaneously in the presence of air and moisture and is the fundamental cause of processes like rusting, in which iron forms iron oxide. The resulting oxide can alter the metal’s properties, sometimes creating a protective layer, while other times leading to degradation.
Metal oxide cycle – It is a thermo-chemical process which uses metal oxides in a cyclic reaction to produce valuable substances like hydrogen or syngas by splitting water or carbon di-oxide. These cycles typically involve high-temperature decomposition of a metal oxide using concentrated solar energy, followed by a subsequent reaction to regenerate the original oxide and produce the desired chemical product.
Metal oxide nano-particles – These are tiny particles, typically 1 nano-meter and 100 nano-meters in at least one dimension, which are composed of metal atoms bonded to oxygen atoms. Their small size gives them unique properties, such as a high surface-area-to-volume ratio, which makes them highly reactive and useful for applications in electronics and catalysis.
Metal-oxide semiconductors (MOS) – These are materials composed of a metal, an insulating oxide layer, and a semi-conductor substrate, frequently used in integrated circuits. They are a type of transistor where a thin oxide layer separates a conductive metal gate from the semiconductor channel, enabling high-density digital circuits with low power consumption.
Metal-oxide-semiconductor field-effect transistor (MOSFET) – It is a type of field-effect transistor (FET), which is normally fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which determines the conductivity of the device. This ability to change conductivity with the quantity of applied voltage can be used for amplifying or switching electronic signals. The main advantage of a MOSFET is that it needs almost no input current to control the load current, when compared to bipolar junction transistors (BJTs).
Metal penetration – It is a surface condition in metal castings in which metal or metal oxides have filled voids between sand grains without displacing them.
Metal pipes and tubes – Metallic pipes are commonly made from iron or steel with the metal chemistry and its finish being peculiar to the use fit and form. Typically, metallic piping can be made of steel or iron, such as unfinished, black (lacquer) steel, carbon steel, stainless steel, or galvanized steel, brass, and ductile iron. Aluminum pipe or tube can be used where iron is incompatible with the service fluid or where weight is a concern. Aluminum is also used for heat transfer tubes such as in refrigerant systems. Copper tube is popular for domestic water (potable) plumbing systems. Copper can also be used where heat transfer is desirable (i.e. radiators or heat exchangers). Inconel, chrome molybdenum, and titanium steel alloys are used for high temperature and pressure piping in process systems where corrosion resistance is important.
Metal plated brick – It is an unburned basic brick with a flat steel plate attached to, and completely covering one or two largest faces.
Metal powder – Metal powder is a metal that has been broken down into a powder form. Metals that can be found in powder form include aluminium powder, nickel powder, iron powder and many more. There are four different ways metals can be broken down into this powder form namely direct reduction, gas atomization, liquid atomization, and centrifugal atomization. Metal powder is elemental metals or alloy particles, normally in the size range of 0.1 micrometers to 1,000 micrometers.
Metal powder cutting – It is a technique which supplements an oxy-fuel torch with a stream of iron or blended iron-aluminum powder to facilitate flame cutting of difficult-to-cut materials. The powdered material propagates and accelerates the oxidation reaction, as well as the melting and spalling action of the materials to be cut.
Metal powder forming – It is also known as powder metallurgy. It is a manufacturing process which uses metal powders to create solid parts without melting and casting. The process involves mixing metal powders, compacting the mixture into a desired shape using a die, and then heating the compressed shape (sintering) to fuse the particles together into a solid mass. This method can produce high-quality, near-net-shaped components with complex geometries.
Metal precursor – It is a chemical compound used as a starting material to produce metal films, nano-particles, or other metal-containing materials. These compounds frequently contain metal atoms bonded to other elements or organic ligands, and they are manipulated through processes like chemical vapour deposition or sol-gel synthesis to deposit or form the desired final product. Examples include metal alkylates, carbonyl compounds, and metal-organic complexes.
Metal puddle – It refers to a pool of molten metal created during processes like welding, casting, or puddling. It is the liquid phase of the metal, formed when the metal’s temperature exceeds its melting point. In welding, it is the localized area where the base metal and filler material melt together. In casting, it is the molten metal poured into a mould. In puddling, it is the molten pig iron being stirred and refined.
Metal recovery – It refers to the process of extracting valuable metals from different sources, such as ores, scraps, industrial waste, and discarded products, with the aim of reusing or recycling them. This practice supports resource sustainability, reducing reliance on virgin metal extraction, and minimizing environmental impact.
Metal rectifier – It is a rectifier made from copper oxide or selenium. It has been formerly widely used before development of silicon rectifiers.
Metal refining – It is the final process of purifying a metal by removing impurities, which yields a commercially pure metal from the crude metal extracted from its ore. Methods for refining include electrolytic, fire, and chemical processes, chosen based on the specific metal and its impurities.
Metal refining process (MRP) converter – The metal refining process is also a duplex process where scrap and raw materials are melted in an electric arc furnace (EAF) or similar unit. Liquid steel, which contains chromium and nickel, is charged to the metal refining process (MRP) converter. Decarburization is carried out using oxygen and inert gases. In early stages of development, the gases have been alternately blown through the tuyeres in the bottom of the reactor. The oxygen is blown into the melt without dilution with any inert gas. The desired oxygen blow is followed by blowing with inert gas only. The cycle of oxygen blow followed by inert blow is called cyclic refining or pulsing and the developers have claimed that the flushing with pure inert gases can lead to achieving low carbon mono-oxide gas partial pressure and faster decarburization and hence lower chromium oxidation and consumption of silicon for reduction. The original version of the converter has now evolved into the MRP-L process in which all oxygen is top-blown and inert gas is injected through the porous elements in the bottom. The process can be used for higher blowing rates than those used in the argon oxygen decarburization (AOD) process, which has side-wall tuyeres. The bottom tuyeres can be replaced easily through the use of an exchangeable bottom. With bottom tuyeres, there is less likely to be erosion on the sidewalls of the vessel. In recent years, the MRP-L converters have been coupled with a vacuum unit as part of the triplex process for making stainless steels, especially those needing lower carbon and nitrogen levels. In these plants, the heats are tapped at an intermediate carbon level appropriate for subsequent vacuum decarburization.
Metal removal – It is the process of eliminating unwanted metal from a work-piece or waste material. ]In manufacturing, it refers to machining, where excess metal is cut away from a work-piece to shape it. In environmental science, it involves removing heavy metal contaminants from waste-water or effluents to meet quality standards.
Metal rod – It is a long, thin bar made of metal, used in several applications like mechanical parts and structural support. Its specific meaning depends on its context, such as a connecting rod in an engine, or a lightning rod for protecting buildings from lightning strikes
Metal rolling – Metal rolling operations are similar in that the work piece is plastically deformed by compressive forces between two constantly spinning rolls. These forces act to reduce the thickness of the metal and affect its grain structure. The reduction in thickness can be measured by the difference in thickness before and after the reduction, this value is called the draft. In addition to reducing the thickness of the work, the rolls also act to feed the material as they spin in opposite directions to each other. Friction is hence a necessary part of the rolling operation, but too much friction can be detrimental for a variety of reasons. It is essential that in a metal rolling process the level of friction between the rolls and work material is controlled, use of lubricants can help with this. During a metal rolling operation, the geometric shape of the work is changed but its volume remains essentially the same.
Metals comparator – It is an instrument used to compare the properties of a metal part against a known standard or master component. Unlike a measuring device which gives an absolute value, a comparator determines the difference or deviation between the test piece and the standard. This is particularly useful in mass production for high-speed quality control. It is an instrument for testing or identifying metallic and nonmetallic parts. Parts are placed in an electromagnetic field and a standard part in a matched electro-magnetic field. Distortions of the magnetic fields are compared on an oscilloscope.
Metal seated valve – In this valve, the sealing contact area is metal to metal between the sealing face of the seat ring and the closure element. For example, in a ball valve, the ball and seats contact and seal area is metal to metal. This is typically used in severe service applications.
Metal-semi-conductor junction – It is the interface formed when a metal and a semi-conductor are in direct contact, creating either a rectifying Schottky junction or a non-rectifying Ohmic contact. The type of junction formed depends on the work functions of the materials and can be used to create electronic devices like Schottky diodes, which only allow current to flow in one direction.
Metal shadowing – It is the improvement of contrast in a microscope by vacuum deposition of a dense metal onto the sample at an angle normally not perpendicular to the surface of the sample.
Metal sheath – It is a protective metal covering for a cable or other object, such as a sword. In electrical applications, it provides mechanical protection, acts as a barrier against moisture, and serves as a path for fault and grounding currents to ensure human safety. In other contexts, it can be a metal plate on a ship’s hull or a close-fitting case for a blade.
Metal sponge – It is a porous metal material which has a high surface area. It can refer to the physical structure of materials like ‘sponge iron’, which is a porous iron produced by reducing iron ore, or to metals used as catalysts, like ‘palladium black’. The term is also used metaphorically for metals which absorb gases, such as hydrogen.
Metal spraying – It consists of coating metal objects by spraying molten metal against their surfaces.
Metal shrinkage – It refers to the reduction in volume which occurs when molten metal cools and solidifies, transitioning from a liquid to a solid state. This phenomenon is a result of the difference in density between the liquid and solid phases of the majority of the metals. As the metal cools, the atoms move closer together, causing a decrease in the overall volume of the material.
Metal stamping – It is a manufacturing process which uses a stamping press and dies to transform flat metal sheets into specific shapes by applying pressure. This cold-forming process can involve a variety of techniques, such as bending, punching, blanking, and embossing, to create parts for several industries.
Metal strain gauge – It is a device which measures strain (deformation) in an object by converting changes in the object’s physical dimensions into changes in electrical resistance. It typically consists of a patterned metal foil or wire on an insulating backing which is bonded to the object being measured. When the object is stressed, the gauge stretches or compresses, which alters the resistance of the metal filament, allowing the strain to be calculated.
Metal studs – These are threaded or unthreaded rods, bolts, or rivets which are attached to a surface or embedded into a base part, allowing for subsequent fastening of mating parts. They can be welded, cast, or potted into different materials, including metals and ceramics, to create a secure connection.
Metal target – It is an object composed of metal which can be characterized and positioned within a detection system, such as a walk-through metal detector, using electromagnetic properties like the polarizability tensor.
Metal thin-film sensor – The main body and the diaphragm of a metal thin-film sensor are normally made of stainless steel. The sensor can be produced with the required material thickness by machining the diaphragm in automatic precision lathes and then grinding, polishing and lapping it. On the side of the diaphragm not in contact with the medium, insulation layers, strain gauges, compensating resistors and conducting paths are applied using a combination of chemical vapour deposition (CVD) and physical vapour deposition (PVD) processes and are photo-litho-graphically structured using etching. These processes are operated under clean room conditions and in specialized plants, in some parts under vacuum or in an inert atmosphere, in order that structures of high atomic purity can be generated. The resistors and electrical conducting paths produced on the sensor are significantly smaller than a micrometer and are thus known as thin-film resistors. The metal thin-film sensor is very stable because of the materials used. In addition, it is resistant to shock and vibration loading as well as dynamic pressure elements. Since the materials used are weldable, the sensor can be welded to the pressure connection. It can be hermetically sealed without any additional sealing materials. As a result of the ductility of the materials, the sensor has a relatively low overpressure range but a very high burst pressure.
Metal tie – It normally refers to a metal cable tie, which is a fastener made from strong, durable metals like stainless steel to bundle, secure, or organize cables and other objects in demanding applications. Less commonly, it can refer to metal railway ties (sleepers) used in track infrastructure or a tie rod, a structural component used for bracing and support.
Metal transfer – It refers to the process in which molten metal droplets are transferred from the electrode to the workpiece during welding, frequently characterized by short circuits between the electrode and the base material, as seen in short circuit metal transfer mode. This method is normally used for welding thin metals and is effective in different positions and for materials such as conventional and stainless steels.
Metal treatment processes – These are the processes where the metal part remains essentially unchanged in shape but undergoes change in properties or appearance. Examples are heat treating, coating, anodizing, and surface hardening.
Metal vapour vacuum arc – It provides a means of creating a dense plasma from a conducting solid material, from which a high current ion beam can be extracted.
Metal wear particles – These are fragments of metal which break off from a surface because of the friction, wear, or stress. These particles are a product of the degradation of moving metal parts and can vary considerably in size, shape, and composition depending on the conditions under which they are formed, such as load, speed, and environment. They can be analyzed in applications like lubricant analysis to understand the condition and potential failure of machinery.
Metal welding – It is a fabrication process which joins two or more metal parts by melting the edges together, with or without the application of pressure or filler material. The heated metal fuses, creating a strong, permanent bond upon cooling.
Metal welding electrodes – These are used for different welding applications including electric arc welding. Electrodes for manual arc welding (sometimes referred to as stick welding) consist of a rod and a coating material. Metal welding electrodes are installed in the weld head to touch and maintain contact with the work-pieces through the full weld schedule. The stick electrodes are consumable, meaning they become part of the weld. Stick welding electrodes vary by size, material, strength, welding position, iron powder in the flux, and soft arc designation. Electrode size (2.5 millimeters, 3.2 millimeters, 4 millimeters and 5 millimeters etc.) indicates the diameter of the rod core. Each electrode has a certain current range. The welding current increases with the electrode size (diameter). The electrodes are normally manufactured in the length of 250 millimeters to 450 millimeters. Metal welding electrodes play three different roles during welding namely (i) maintaining uniform current density, (ii) concentrating current at welding points, and (iii) maintaining thermal balance during welding. As a rule, the alloy in the rod is similar to the material to be welded. It is made out of materials with a similar composition to the metal being welded.
Metal wire – It is a slender, flexible strand of metal, frequently made from steel, copper, or aluminum, used for purposes like electrical conductivity, fastening, or forming structural elements. It is typically circular in cross-section and can be produced in several diameters, either as a single strand or twisted into cables.
Metal working – It consists of making a change, with the exception of shearing or blanking, in the shape or contour of a metal part without intentionally altering its thickness. It means the plastic deformation of a billet or a blanked sheet between tools (dies) to get the final configuration. Metal forming processes are typically classified as bulk forming and sheet forming.
Metal-working fluids – These are liquids used in metal-working processes like machining and grinding to cool, lubricate, and clean the work area. These are crucial for optimizing performance by reducing friction and heat, dissipating heat, removing chips, and preventing corrosion on both the work-piece and tools. Metal-working fluids are complex mixtures which can contain oils, emulsifiers, and different additives, and are categorized by their composition as either oil-based, water-based (soluble or semi-synthetic), or synthetic.
Metal working processes -These are the deformation processes in which a metal billet or blank is shaped by tools or dies. In metal working, an initially simple work-piece (e.g., a billet or a blanked sheet) is plastically deformed between tools (or dies) to get the desired final configuration. The design and control of such processes depend on the characteristics of the work-piece material, the conditions at the tool / work-piece interface, the mechanics of plastic deformation (metal flow), the equipment used, and the finished-product requirements. These factors influence the selection of tool geometry and material as well as processing conditions (e.g., work-piece and die temperatures, and lubrication). Because of the complexity of several metal working operations, models of different types, such as analytical, physical, or numerical models are frequently relied upon to design such processes.
Metal working saw – It is a cutting tool, either a handheld device like a hacksaw or a larger machine like a bandsaw or chop saw, which uses a toothed blade to cut metal. These saws are designed for cutting metal materials into desired lengths or shapes.
Metal working tools – These are implements used to shape, form, cut, and join metal to create objects. They include both manual hand tools, like hammers and files, and power-driven machine tools, such as lathes and drills, and are necessary for processes like fabrication, cutting, and casting. These tools are designed for precision and durability, enabling the transformation of raw metal into functional or decorative parts and structures.
Metal wrap – It is a protective covering for metal products used in storage and transport, designed to prevent damage from corrosion, abrasion, and moisture. These wraps are typically made from durable, multi-layered materials, frequently incorporating a ‘volatile corrosion inhibitor’ (VCI) additive which releases a vapour to prevent rust and degradation. Metal wraps can also refer to a type of solar cell design or a jewelry-making technique, depending on the context.
Metal yield – It refers to the quantity of usable metal recovered after a processing stage, typically melting or casting, compared to the quantity of metal input. It is essentially a measure of efficiency, indicating how much of the starting material is successfully transformed into a usable product, with the remainder frequently ending up as scrap or waste. High yield is desirable as it reduces waste and costs. Metal yield is expressed in percentage.
Metamorphic rocks – These are the rocks which have undergone a change in texture or composition as the result of heat and / or pressure.
Metamorphism – It is the process by which the form or structure of rocks is changed by heat and pressure.
Meta-morphogenic (metamorphosed) deposits – These deposits of iron ore are pre-existing primarily sedimentary deposits which are transformed under conditions of high temperature and pressure. Under such conditions, hydrous ferric oxides and siderite normally become hematite and magnetite. Metamorphic processes are sometimes supplemented by hydro-thermal-metasomatic formation of magnetite ores.
Metamorphosed iron formations – These include the metamorphosed bedded ferruginous rocks composed usually of alternating thin layers of fine-grained quartz and ferric oxides. The iron is normally present in the mineral form of magnetite or hematite, along with lesser amounts of iron silicates and iron carbonates. Essentially all of the Precambrian sedimentary iron formations are of this type. The metamorphosed types also include those in which the original form of the ores has been obscured by extensive recrystallization. Some of these iron formations are important economically as iron ores because of their amenability to beneficiation by fine grinding and by concentration of the ore minerals principally by magnetic methods.
Metastable – It means a material which is not truly stable with respect to some transition, conversion, or reaction but stabilized kinetically either by rapid cooling or by some molecular characteristics as, for example, by the extremely high viscosity of polymers. It also means possessing a state of pseudo-equilibrium which has a free energy higher than that of the true equilibrium state.
Metastable alloys – These are materials which exist in a state of relative stability, but are not the most thermodynamically stable form for a given composition and temperature. They are not in their lowest energy state, but are kinetically hindered from transitioning to a more stable phase, meaning they can persist for a considerable time. Essentially, they are ‘trapped’ in a state which is not the most energetically favourable, but also not immediately unstable.
Metastable beta – It is a beta-phase composition which can be partially or completely transformed to martensite, alpha, or eutectoid decomposition products with thermal or strain-energy activation during subsequent processing or service exposure.
Metastable beta-alloys – These are titanium-based alloys which are designed to retain their high-temperature, body-centered cubic (BCC) beta phase even at room temperature after quenching. These alloys are strengthened through age hardening and are characterized by a balance of desirable properties, including high strength, low elastic modulus, excellent fatigue resistance, and good formability. They are used in demanding applications because of their strength-to-weight ratio and other unique characteristics like shape memory and super-elasticity.
Metastable equilibrium – It exists when additional energy is required to be introduced before the object can reach true stability.
Metastable melting point – It refers to the temperature at which a metastable phase can melt, typically occurring at a lower temperature than the stable phase, and necessitating a certain degree of undercooling for its formation.
Metastable phase – It is a state of a system which is temporarily stable, meaning it can exist for a substantial period even though it is not in the lowest possible energy state. It is like being in a small valley of potential energy rather than the lowest valley, and it needs a small quantity of ‘activation energy’ to transition to a more stable state. Examples include supercooled water, which remains liquid below its freezing point, or metastable materials used in engineering which have unique properties.
Metastable state – It is an excited state of a system which is stable enough to last for a much longer time than a typical excited state, but it is not the most stable, lowest-energy state. It acts as a temporary energy trap, remaining in this state until a large enough disturbance allows it to transition to a more stable state, like the ground state. This concept is important, especially for laser operation where a population inversion is needed.
Metastability – It is an intermediate energetic state within a dynamical system other than the system’s state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball is only slightly pushed, it will settle back into its hollow, but a stronger push can start the ball rolling down the slope.
Meta-surfaces – These are two-dimensional structures composed of a periodic array of antennas with a thickness smaller than the wavelength of incident electromagnetic waves, which introduce abrupt phase changes to scattered waves, allowing for advanced control over light propagation.
Meta-Xylene, m-xylene – It is an aromatic hydrocarbon. It is one of the three isomers of di-methyl-benzene known collectively as xylenes. The m– stands for meta–, indicating that the two methyl groups in m-xylene occupy the diametrically opposite substituent positions 1 and 3. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and p-xylene. All have the same chemical formula C6H4(CH3)2. All xylene isomers are colourless and highly flammable.
Meteorology – It is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting.
Meteorological elements – These refer to the variables used to quantify climate in a specific region, including average temperature, precipitation, wind, pressure, cloudiness, and humidity. These elements are necessary for understanding the expected weather patterns and characteristics of an area during a certain month or season.
Meter – It is the fundamental unit of length in the metric system and the International System of Units (SI). It is equivalent to 39.37 inches. It was originally intended to be, and being very nearly, equal to one ten-millionth of the distance from the equator to the pole measured on a meridian. It was defined from 1889 to 1960 as the distance between two lines on a platinum-iridium bar (the ‘International Prototype Meter’) preserved at the International Bureau of Weights and Measures near Paris. From 1960 to 1983, it was defined as 1,650,763.73 wave-lengths of the orange-red radiation of krypton 86 under specified conditions. Now it is defined as 1/299,792,458 of the distance light travels in a vacuum in one second. Meter is also an instrument for measuring, especially one that automatically measures and records the quantity of something, as of gas, water, miles, or time, when it is activated.
Metering – It is the act of using a meter for measurement. It is the use of meters to measure how much gas, electricity, or water is used.
Meter prover – It is a system which is used to check or ‘prove’ a flow meter. A close-fitting sphere is launched into a pipe of known inside diameter. The flow medium pushes the sphere through a measured length of pipe between two sphere detection devices. By knowing the transit time and the exact volume between the two stations, a flow rate is calculated and compared with the meter reading.
Meter run – It is a section of pipeline in which a meter is installed to measure the volume of fluid passing through the line.
Meter tube – It is the pipe section which houses the orifice plate and can include straightening vanes to reduce flow disturbances, with its dimensions determined by the orifice to pipe diameter ratio, known as the beta ratio.
Methacrylate group – It is a functional group derived from methacrylic acid, consisting of a C=C double bond adjacent to a carbonyl group (C=O). It is the anion or ester of methacrylic acid and is known for its ability to polymerize into different plastics and resins, like Plexiglas [poly (methyl methacrylate)].
Methacrylate monomer – It is a type of organic compound that serves as a building block for creating polymers, most notably poly (methyl methacrylate) (PMMA). These monomers are versatile, can be synthesized from both fossil and renewable sources, and are used in a wide variety of applications, including adhesives, coatings, and plastics like acrylic glass. The process of turning these monomers into polymers involves a chain reaction called polymerization, where several individual monomer molecules link together to form a long-chain
Methacrylic – It refers to a class of polymers related to acrylics, with poly (methyl methacrylate) (PMMA) being the most common type. These polymers are known for their transparency, hardness, and durability, although they show brittleness and limited resistance to extreme temperatures and solvents.
Methacrylic acid (MAA) – It is a chemical compound, specifically an organic acid, that is an alpha, beta-unsaturated monocarboxylic acid. It is a colourless, viscous liquid with a pungent, acrid odor. MAA is a building block for various esters, most notably methyl methacrylate (MMA) and poly (methyl methacrylate) (PMMA).
Methanation – It is the transformation of syngas into methane, involving the reaction of carbon mono-oxide and hydrogen to produce methane and water, and is significant for its industrial applications, including the reduction of carbon mono-oxide impurities in hydrogen production.
Methane – It is a chemical compound with the chemical formula CH4 (one carbon atom bonded to four hydrogen atoms). It is the simplest alkane, and the main constituent of natural gas. It is an economically attractive fuel, although capturing and storing it is difficult since it is a gas at standard temperature and pressure. It is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Methane is an organic compound, and among the simplest of organic compounds. Methane is also a hydrocarbon.
Methane capture – It is the process of collecting methane gas from sources like landfills and fossil fuel production to prevent its release into the atmosphere. This captured methane can then be used as a renewable energy source or for other purposes, mitigating its impact as a potent greenhouse gas.
Methane compressor – It is a device which increases the pressure of methane gas, which is the main component of natural gas and biogas. By reducing the volume and increasing the pressure, methane can be transported over long distances, stored more efficiently, or processed further for several applications, such as injecting it into the natural gas grid.
Methane partial oxidation – It is a chemical process where methane (CH4) reacts with a limited quantity of oxygen to produce a mixture of hydrogen (H2) and carbon mono-oxide (CO), known as synthesis gas or syngas. Unlike complete combustion, which yields only carbon di-oxide and water, this controlled process aims to maximize the H2 and CO products, making it a key method for producing syngas. This reaction is highly exothermic and typically occurs at high temperatures, frequently catalyzed.
Methane steam reforming – It is an industrial process which reacts methane with high-temperature steam, in the presence of a catalyst, to produce hydrogen and carbon mono-oxide. This endothermic reaction needs heat to proceed and is the most common method for producing hydrogen from natural gas on a large scale. The main chemical reaction is CH4 + H2O = CO + 3H2. .
Methane sulphonic acid (MSA) – It is an organo-sulphuric, colourless liquid with the molecular formula CH3SO3H and structure H3C-S(=O)2-OH. It is the simplest of the alkyl-sulphonic acids (R-S(=O)2-OH). Salts and esters of methane-sulphonic acid are known as mesylates (or methane-sulphonates, as in ethyl methane-sulphonate). It is hygroscopic in its concentrated form. Methane-sulphonic acid can dissolve a wide range of metal salts, several of them in considerably higher concentrations than in hydrochloric acid (HCl) or sulfuric acid (H2SO4).
Methanogenic phase – It refers to the stage in biogas production where methane and carbon di-oxide are formed from the hydrogen produced during the acidogenic phase, utilizing acetate and other substrates.
Methanol – It is the primary alcohol used in the chemical process called transesterification to produce biodiesel from vegetable oils or animal fats. Biodiesel itself is a fuel made of fatty acid methyl esters (FAME) which can be used in diesel engines alone or blended with petroleum diesel. Methanol is preferred due to its low cost and high reactivity.
Methanol steam reforming – It is defined as a process which utilizes methanol and water to generate hydrogen (H2) and carbon di-oxide (CO2) through reactions facilitated by high temperature and catalysts. It is characterized by low reaction temperature, high hydrogen yield, and low carbon mono-oxide (CO) content, although it faces challenges such as being endothermic and needing substantial external heat.
Methanol synthesis – It is the industrial process of producing methanol by reacting hydrogen with carbon mono-oxide (CO) and / or carbon di-oxide (CO2) over a catalyst, typically at high temperatures and pressures. This process is used to create methanol from synthesis gas (syngas), which can be derived from sources like natural gas or coal, or through newer methods which use captured CO2 and hydrogen produced from renewable energy.
Methanol to gasoline process – It is a method for converting methanol into gasoline, utilizing zeolite catalysts to produce low-sulphur gasoline from hydro-carbons. This process is advantageous because of its ability to efficiently produce gasoline from methanol derived from natural gas and flare gases.
Methodical approach – It is a systematic and organized way of doing something, following a clear, step-by-step process with care and attention to detail. It involves planning and executing tasks in a logical sequence to ensure thoroughness and minimize mistakes.
Method of least squares – It is a statistical technique used to find the best-fitting curve or line for a set of data points. It works by minimizing the sum of the squared differences (residuals) between the observed values and the values predicted by the curve. This method is fundamental in regression analysis and is used to predict behaviour, model relationships between variables, and perform error analysis.
Method of measurement – It is a logical sequence of operations, described generically, used in the performance of measurements. Methods of measurement can be qualified in various ways, such as (i) substitution method, (ii) differential method, and (iii) null method.
Method validation – It is a documented process to confirm that an analytical method is suitable for its intended purpose by demonstrating its accuracy, precision, and reliability. This involves rigorous testing to prove the method’s performance characteristics, such as specificity, linearity, and robustness, are consistent and acceptable for its specific application. It is a critical part of good laboratory practice and is frequently needed for quality control and regulatory compliance.
Methyl-acetylene-propadiene-stabilized (MPS) – It is a fuel gas mixture containing methyl-acetylene (propyne) and propadiene, stabilized with other hydro-carbons like propane and butane. It is frequently referred to by the trade name MAPP gas and is normally used for cutting, welding, and heating in those processes. Unlike liquefied petroleum gas (LPG), Methyl-acetylene-propadiene-stabilized is specifically classified as a fuel gas.
Methyl-cyclo-hexane – It is a cyclic alkane with the chemical formula C7H14. It consists of a cyclo-hexane ring with a methyl group (CH3) attached to one of the carbons. It is a colourless liquid with a faint, petroleum-like odour and is used as a solvent and in the production of other organic chemicals.
Methylene chloride – It is also known as dichloromethane (CH2Cl2). It is a solvent which shows weak reactivity with aluminum at room temperature but causes substantial thickness reduction of aluminum at high temperatures, particularly over 14 millimeters per year at 120 deg C in its liquid phase.
Methylene di-aniline (MDA) – It is an organic compound with the formula CH2(C6H4NH2)2. It is a colourless solid, although commercial samples can appear yellow or brown. It is produced on an industrial scale, mainly as a precursor to polyurethanes.
Methyl diethanolamine (MDEA) – It is a tertiary amine compound with the chemical formula CH3N(C2H4OH)2. It is a colourless, viscous liquid with a faint ammonia odour. Methyl diethanolamine is mainly used as a gas sweetening agent in the chemical, oil refining, and natural gas industries to remove hydrogen sulphide (H2S) and carbon di-oxide (CO2) from gas streams.
Methylene diphenyl diisocyanate (MDI) – It is an aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. The 4,4′ isomer is most widely used, and is also known as 4,4′-diphenylmethane diisocyanate. This isomer is also known as pure MDI. MDI reacts with polyols in the manufacture of polyurethane. It is the most produced diisocyanate.
Methylene green – It is a cationic dye which is normally studied for its adsorption properties, particularly in the context of removing pollutants from industrial waste-water using different adsorbents, including agricultural waste.
Methyl ester – It is a chemical compound formed by replacing the hydrogen atom of the carboxyl group (-COOH) in a fatty acid with a methyl group (-CH3). Essentially, it is a fatty acid with a methyl group attached to the oxygen of the carboxyl group.
Methyl ethyl ketone (MEK) – It is also known butanone, or ethyl methyl ketone. It is an organic compound with the formula CH3C(O)CH2CH3. This colourless liquid ketone has a sharp, sweet odour reminiscent of acetone. It is produced industrially on a large scale, but occurs in nature only in trace amounts. It is partially soluble in water, and is normally used as an industrial solvent. It is an isomer of another solvent, tetrahydrofuran.
Methyl ethyl ketone peroxide – It is a chemical compound categorized as a peroxide, with the formula being a solution in dimethyl phthalate, and is utilized mainly as a curing agent for unsaturated polyester resins and related applications.
Methyl isobutyl ketone (MIBK) – It is an organic compound with the condensed chemical formula (CH3)2CHCH2C(O)CH3. This ketone is a colourless liquid which is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose.
Methyl mercaptan – It is also known as methanethiol (CH3SH). It is a toxic and highly flammable colourless gas with a pungent, foul odour frequently compared to rotten cabbage. It is is used industrially as an odourant to detect leaks in otherwise odourless gases like natural gas. Because of its toxicity, methyl mercaptan is considered a regulated toxic substance and can cause health effects like irritation, narcosis, and, in high concentrations, more severe issues.
Methyl mercury – It is an organometallic cation with the formula (CH3Hg)+. It is the simplest organomercury compound. Methyl mercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a bio-accumulative environmental toxicant with a 50-day half-life.
Methyl methacrylate (MMA) – It is an organic compound with the formula CH2=C(CH3)COOCH3. This colourless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly (methyl methacrylate) (PMMA).
Metrics – These are quantifiable measurements used by an organization to track, analyze, and evaluate its performance and progress toward strategic goals. By using a combination of metrics, organizations can monitor the health of different functions like finance, sales, and operations to make informed decisions, identify areas for improvement, and gauge the effectiveness of their strategies.
Metric system – It is a decimal-based system of measurement used globally, based on seven base units for physical quantities like length, mass, and time, which include the meter, kilogram, and second. It uses prefixes for multiples and fractions of base units, such as kilo- (1000) and centi- (1/100), which makes conversions straightforward. The modern version of the metric system is the International System of Units (SI).
Metric ton – It is a unit of measurement for mass. It is equal to 1,000 kilograms, or one megagram (one million grams). When people talk about a ton, in countries which use the SI (International System of Units) system of units, they mean the metric ton. The metric ton is normally abbreviated to ‘t’
Metrology – It is the science of measurement. Metrology includes all aspects, both theoretical and practical, with reference to measurements, whatever their uncertainty, and in whatever fields of science or technology they occur.
Metropolis Monte Carlo (MMC) algorithm – It is a simulation technique which utilizes random movements of particles to explore different configurations of a system, assessing the potential energy of these states to efficiently find the equilibrium state, regardless of the initial configuration. It incorporates a probabilistic acceptance criterion for new states based on the change in potential energy, allowing the system to eventually reach equilibrium even if some transitions increase energy.
Meyer hardness test – It is a hardness test which measures a material’s resistance to indentation by dividing the applied load by the projected area of the indentation, not the surface area. This mean pressure, calculated as Hm = 4P/[Pi(d square)], where ‘P’ is the load and ‘d’ is the indentation diameter, provides a more fundamental measure of hardness, especially for cold-worked materials where the value remains constant regardless of load.
‘Mf’ temperature – For an alloy system, it is the temperature at which martensite formation on cooling is essentially finished.
MGD – It means million gallons per day. It is a measure of water flow. It is frequently used for indicating the treatment capacity of waste treatment plants or production capacity of drinking water treatment plants.
M-glass – It is a high beryllia (BeO2) content glass which is designed especially for high modulus of elasticity.
MHI gasifier – The Mitsubishi Heavy Industries (MHI) gasifier is based upon the Combustion Engineering air-blown slagging gasifier and co-developed between Combustion Engineering (and its subsequent owners) and Mitsubishi Heavy Industries. It has a dry feed system, suitable for low rank coals having high moisture contents. It is an air blown two-stage entrained bed slagging gasifier utilizing membrane water-wall construction.
Mho – It is the reciprocal of an ohm, representing a unit of electrical conductivity, which has been renamed to Siemens (S) by International Organization for Standardization.
Micas – These are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock.
Mica Schist – It is a type of micaceous refractory rock used for lining cupolas and other melting furnaces. It is a type of metamorphic rock composed mainly of platy mica minerals (like muscovite and biotite) and quartz. It is formed under medium-grade metamorphic conditions from precursor rocks like mudstones or shales. Its key characteristic is ‘schistosity’ i.e., the parallel alignment of mica minerals which causes the rock to split easily into thin, flaky layers.
Mica strainer – It is a perforated sheet of mica used as a filter during the casting of molten metal. It is also called a mica strainer core. It is a thin, inorganic, non-contaminating, and non-moisture-absorbent material. The main applications of a mica strainer are in foundries which produce non-ferrous and some smaller ferrous castings, including brass, bronze, aluminum, and sand castings.
Micellar electro-kinetic chromatography (MEKC) – It is a hybrid technique which combines aspects of capillary electrophoresis and chromatography to separate both neutral and charged molecules. It works by adding surfactants to a buffer, which form micelles which act as a pseudo-stationary phase. Solutes separate based on how they partition between these micelles and the aqueous buffer, driven by an electric field.
Micellar solutions – These are aqueous solutions of surfactants which contain amphiphilic aggregates formed at concentrations above the critical micellar concentration (CMC), which can be either monodisperse or polydisperse depending on different factors such as surfactant structure and concentration.
Micelle – It is a sub-microscopic unit of structure built up from ions or polymeric molecules.
Michell equation – It refers to a set of equations used to describe the equilibrium of elastic solids, specifically addressing compatibility conditions necessary for the deformation of materials under stress, such as in the case of an elastic sphere under uniform pressure.
Michelson interferometer – It utilizes interference to make precise measurements of wave-length, distances, and refractive indices by splitting a light beam into two paths, introducing a phase difference, and then recombining them to form an interference pattern. The derivation of its key equations involves understanding the path difference between the two beams and how this difference relates to the observed interference pattern.
Micro – It refers to technology and processes operating at a miniature scale, typically involving dimensions from micro-meters to milli-meters. It can also refer to the prefix for one millionth and is used across various fields, such as micro-electronics, micro-systems engineering, and micro-materials science, to describe very small components, frequencies, or quantities. In relation to composites, it denotes the properties of the constituents, i.e., matrix, reinforcement, and interface only, and their effects on the composite properties.
Micro-accelerometer – It is a miniaturized device which measures acceleration, gravity, and vibration by using micro-machined structures integrated with electronic circuits, frequently based on MEMS (micro-electro-mechanical systems) technology. It detects the displacement of a small mass relative to fixed electrodes or uses principles like the piezo-electric effect to convert motion into an electrical signal. These sensors are normally used in automotive safety and structural monitoring.
Micro-alloyed steels – These are carbon-manganese steels containing deliberately added alloying elements totalling in the range of 0.05 % to 0.10 %. Alloying elements which are effective in modifying steel properties when present in such small quantities include boron, vanadium, and niobium. These steels are also sometimes called high strength low alloy (HSLA) steels. These steels are a group of low carbon steels which utilize small quantities of alloying elements to attain yield strengths higher than 275 mega-pascals in the as-rolled or normalized condition. These steels have better mechanical properties and sometimes better corrosion resistance than as-rolled carbon steels. Also, since the higher strength of the micro-alloyed steels can be achieved at lower carbon contents, the weldability of several micro-alloyed steels is comparable to or better than that of the mild steel. A major advantage of these steels is that in the case of forgings, careful control of forge processing temperatures can eliminate subsequent heat treatment. Mechanical properties developed by controlled hot working conditions are similar to those developed by conventional hardening and tempering treatments for components where strength and toughness are needed.
Micro-alloyed ferrite-pearlite steels – These steels use additions of alloying elements such as niobium and vanadium to increase strength (and thereby increase load-carrying ability) of hot rolled steel without increasing carbon and / or manganese contents. The mechanical properties of the micro-alloyed steels result, however, from more than just the mere presence of micro-alloying elements. Austenite conditioning, which depends on the complex effects of alloy design and rolling techniques, is also an important factor in the grain refinement of hot rolled micro-alloyed steels. Grain refinement by austenite conditioning with controlled rolling methods has resulted in improved toughness and high yield strengths in the range of 345 MPa to 620 MPa. The different types of micro-alloyed ferrite-pearlite steels include (i) vanadium micro-alloyed steels, (ii) niobium micro-alloyed steels, (iii) niobium-molybdenum steels, (iv) vanadium-niobium micro-alloyed steels, (v) vanadium-nitrogen micro-alloyed steels, (vi) titanium micro-alloyed steels, (vii) niobium-titanium micro-alloyed steels, and (viii) vanadium-titanium micro alloyed steels. These steels can also include other elements for improved corrosion resistance and solid-solution strengthening, or improved hardenability (if transformation products other than ferrite-pearlite are desired).
Micro-alloying – It is a steelmaking technology in which small quantities of alloying elements (vanadium, niobium, or titanium) are used to retard recrystallization of austenite, thereby allowing a wider range of rolling temperatures for controlled rolling. Without retarding recrystallization, as in normal hot rolling, the pancake-type grains do not form and a fine grain size cannot be developed in these ferrite-pearlite steels.
Micro-alloying additions – These refer to the small quantities of elements such as niobium, titanium, or vanadium which are incorporated into steel to improve its mechanical properties by influencing the austenite to ferrite transformation, forming precipitates, and affecting hardenability and microstructural development.
Micro-alloying elements – These are those alloying elements which are added in small quantities singly or in combinations for refining the grain micro-structure or facilitating the precipitation hardening. Examples of microalloying elements are niobium, vanadium, titanium, molybdenum or boron.
Micro-analysis – It consists of the analysis of samples smaller than 1 milligram.
Micro and nano steel mills – These are steel mills with a capacity of 0.2 million ton per annum to 0.5 million ton per annum utilizing endless rolling to achieve an operating cost lower than a 1 million ton per annum steel plant.
Micro-bands – These consist of thin, sheetlike volumes of constant thickness in which cooperative slip occurs on a fine scale. These are an instability which carry exclusively the deformation at medium strains when normal homogeneous slip is precluded. The sheets are aligned at +/- 55-degree to the compression direction and are confined to individual grains, which usually contain two sets of bands.
Microbe– It is also known as micro-organism. It is an organism of microscopic size, which can exist in its single-celled form or as a colony of cells. Microbes are tiny living things that are found all around us. They are too small to be seen by the naked eye.
Microbial electrolysis cell (MEC) – It is a bio-electro-chemical system which uses micro-organisms and a small electrical voltage to convert organic matter into hydrogen gas. Microbes in an anaerobic anode chamber oxidize organic waste, and their electrons are transferred to a cathode chamber where water is electrolyzed to produce hydrogen (H2). This process is a promising way to generate clean hydrogen while simultaneously treating waste-water.
Microbially (micro-biologically) induced corrosion (MIC) – It is corrosion which is caused by the presence and activities of micro-organisms. Micro-organisms are the organisms which cannot be seen individually with the unaided human eye, including microalgae, bacteria, and fungi. Microbially induced corrosion can cause various forms of localized corrosion, including pitting, dealloying, enhanced erosion corrosion, enhanced galvanic corrosion, stress corrosion cracking, and hydrogen embrittlement. As a result of microbially induced corrosion, corrosion can occur at locations where it is not predicted, and it can occur at very high rates. The iron and steel materials undergo microbially induced corrosion. Furthermore, microbially induced corrosion can also take place in seawater, fresh water, distilled / demineralized water, hydrocarbon fuels, process chemicals, foods, soils, human plasma, saliva, and sewage.
Microbial metallurgy – It is also known as bio-hydro-metallurgy or bio-mining. It, is the field which studies and applies the interactions between micro-organisms and minerals to extract and recover metals from ores and other solid materials.
Micro-cantilever – It is a small, beam-like structure which is fixed at one end and is used as a sensor in micro-electro-mechanical systems (MEMS). It bends or vibrates in response to external forces, such as a change in mass or surface stress, which can be detected to measure physical, chemical, or biological substances with high sensitivity.
Micro cast process – It is a metal forming technique used to produce miniature metal parts with extremely fine details, frequently in the micro-meter range. It is an advanced version of investment casting, also known as lost-wax or lost-mould casting. Specialized materials and controlled parameters are necessary to successfully cast these small, intricate components.
Microcavity – It is a microscopic cavity, frequently found in advanced optical devices or microfluidic systems. In an optical context, itis a structure which confines light in a small space to improve light-matter interactions, with a size comparable to the wavelength of light. In a broader engineering sense, it can also refer to a tiny hole or cavity created by processes like micro-machining.
Microchip – It is a set of electronic circuits on one small plate of semi-conductor material, normally silicon.
Microchip capillary electrophoresis – It is a highly effective separation method which utilizes integrated microchips for the separation of small molecules, offering advantages in miniaturization and compatibility with different functional units.
Micro-circuit drawing – It specifies the engineering requirements and establishes item identification for a microcircuit. It is prepared to establish the physical and functional characteristics necessary to ensure microcircuit interchangeability. It includes (i) outline and mounting requirements, (ii) performance requirements, (iii) schematic diagrams showing functional electrical elements of the microcircuit, (iv) marking requirements, (v) identification of input and output pin functions, and (vi) quality assurance provisions.
Micro-climate – It is a local set of atmospheric conditions which differ from those in the surrounding areas, frequently slightly but sometimes substantially. The term can refer to areas as small as a few square meters or smaller or as large as several square kilometers. Since climate is statistical, which implies spatial and temporal variation of the mean values of the describing parameters, micro-climates are identified as statistically distinct conditions which occur and / or persist within a region.
Micro-column – It refers to a small-scale structure or component, typically with dimensions in the micrometer to sub-millimeter range, used in specialized applications such as micro-electromechanical systems (MEMS), gas chromatography, and material testing.
Micro combined heat and power – It is the equipment which generates process or space heat and electric power, of a size useful for a single building.
Micro-controller – It is a micro-processor which is integrated with memory and input/output circuits. It is useful for embedded control.
Micro-crack – It is a crack of microscopic proportions. It is also termed micro-fissure.
Micro-crystalline – It describes a material composed of very small crystals which are only visible under a microscope. This structure results in desirable properties like high strength, wear resistance, and corrosion resistance, depending on the specific material. Examples include microcrystalline silicon for electronics and microcrystalline wax for industrial applications like coatings and lubricants.
Micro-crystalline silicon – It is a mixed-phase semiconductor material composed of tiny silicon crystallites embedded in an amorphous silicon matrix. It is produced using lower-temperature deposition methods like plasma-enhanced chemical vapour deposition (PECVD) compared to poly-crystalline silicon. This structure allows it to have properties of both crystalline silicon (like stability) and amorphous silicon (like a broader light absorption spectrum), making it useful for applications such as solar cells and thin-film transistors.
Micro-damage – It is the formation of microscopic cracks and other defects in a material, which occurs under mechanical stress, particularly cyclic loading, and can lead to eventual failure. It is a key concept in the field of damage mechanics, which studies the effects of this microstructural damage on a material’s overall macroscopic properties, such as strength, stiffness, and fracture resistance.
Micro-electro-mechanical systems (MEMS) – These are electro-mechanical systems of microscopic size. These can be sensors or actuators. Micro-electro-mechanical systems is the technology of microscopic devices incorporating both electronic and moving parts. These devices are made up of components between 1 micrometer and 100 micrometers in size. These devices normally range in size from 20 micrometers to 1 millimeter, although components arranged in arrays can be more than 1,000 square millimeters. They normally consist of a central unit which processes data (an integrated circuit chip such as microprocessor) and several components which interact with the surroundings (such as microsensors).
Micro-electronics – It consists of that part of the field of electronics which is dealing with integrated circuits.
Micro-emulsions (semi-synthetics) – Sometimes, a metal working operation needs a lubricant which provides outstanding flushing, cooling, and improved lubricating qualities. Micro-emulsions are ideal for use on galvanized, hot rolled, cold rolled, and stainless steel. Micro-emulsions provide some film strength from the combination of emulsifiers, water-soluble corrosion inhibitors, wetting agents, organic and inorganic salts, and sometimes extreme pressure agents. Micro-emulsions are emulsions in which the dispersed particles are in the range of 0.01 mm to 0.06 mm. These emulsions are usually translucent or transparent in appearance. Their small particle size provides excellent penetration and cooling for various types of metal working. Micro-emulsions can be sprayed, roller-coated or used in a flood-type coolant system.
Micro-etching – It is the development of micro-structure for microscopic examination. The normal magnification exceeds 25× (50× in some countries).
Micro-fabrication – It is a set of engineering processes for creating microscopic structures and devices, most commonly on silicon wafers, but also using other materials like glass, polymers, and plastics. These processes build intricate features for applications in fields like semiconductors, microelectronics for creating devices like MEMS (micro-electro-mechanical systems) and micro-fluidic chips. Techniques include photo-lithography, etching, deposition, and doping, which use ‘top-down’ methods (shaping from a bulk material) or ‘bottom-up’ methods (assembling small parts).
Micro-farad – It is a unit of electrical capacitance, defined as one-millionth of a farad. It is a practical and common unit for measuring the ability of a component, like a capacitor, to store an electrical charge. For example, a capacitor with a value of 450 micro-farad can store 450 micro-farads of charge.
Micro-features – These are small-scale components or geometric patterns with at least one dimension below 1 millimeter. They are created using specialized micro-fabrication techniques and are critical for applications like micro-electro-mechanical systems (MEMS) and cooling systems. The properties of a surface can be altered by adding micro-scale patterns, which can be used to increase effective surface area.
Micro-filtration (MF) – It is a pressure-driven membrane filtration process which uses membranes with pores typically ranging from 0.1 micro-meters to 10 micrometers to physically remove suspended solids, micro-organisms, and other particles from liquids.
Micro-finishing – It is also known as superfinishing or micro-machining. It is a precision machining process which refines the surface of a work-piece to achieve an extremely smooth and accurate finish. It involves removing a thin layer of material (frequently just a few micrometers thick) to eliminate surface imperfections like tool marks, burrs, and other irregularities left by previous machining operations. This results in a surface with very low roughness and improved dimensional accuracy, which is crucial for applications where friction, wear, and performance are critical.
Micro-finishing grinding – It is a precision grinding process which uses extremely fine abrasive (50 micrometers and finer).
Micro-fissure – It is a crack of microscopic proportions. It is also termed micro-crack.
Micro-fluidic fuel cells – These are defined as a novel fuel cell technology characterized by low fabrication costs, flexible material selection, and high performance at room temperature, although they currently face challenges related to water management, portability, and power output.
Micro-fluidic device – It is an instrument which manipulates and processes fluids within micrometer-scale channels, frequently integrated into a ‘lab-on-a-chip’. These devices use very small volumes of fluid and feature components like micro-channels, reaction chambers, and sensors to perform laboratory tests or chemical analyses. They enable the miniaturization of complex processes with advantages such as reduced sample and reagent use, faster analysis times, and portability.
Micro-fluidic technology – It is an engineering discipline which involves the manipulation of tiny volumes of fluids using microchannels with dimensions of tens to hundreds of micro-meters. It is a multi-disciplinary field which integrates concepts from chemistry, physics, biology, and micro-electronics to create lab-on-a-chip devices that can automate, integrate, and miniaturize processes like mixing, separation, and chemical analysis.
Micro-forming – It is a technological process normally defined as the production of parts or structures with at least two dimensions in the sub-millimeter range. Most of the developments in this area have been driven by the needs of the electronics industry for mass produced miniature parts. Major challenges in micro forming fall into one of the four broad categories namely (i) material of the work piece, (ii) tooling, (iii) equipment, and (iv) process control. As an example, the flow and failure behaviour of a work-piece with only one or several grains across the section subjected to large strains can be very different from that of its poly-crystalline counterpart used in macro bulk forming processes. Micro forming operations include cold heading and extrusion of wire.
Micro-fractography – It is a key technology used to clarify the failure mechanisms of machines and structures by analyzing fracture surfaces in different contexts, including corrosion fatigue and high-temperature failures.
Micro-fracture – It refer to a small crack in a material caused by stress. It is a tiny crack in a substance, frequently from mechanical stress, which can be seen only under magnification. It is a type of wear that allows a grain to maintain its sharpness while experiencing a slow rate of wear under high stress conditions. It is dependent on the crystalline nature of the grain.
Micro fuel cell – It is a compact, small-scale device which generates electricity through a chemical reaction, designed for low-power electronic devices. These devices convert chemical energy into electrical energy, and are frequently used in portable electronics or in low-power remote applications. Unlike traditional fuel cells, they are made small and need new designs to operate effectively.
Micro gas turbine – It is a compact, high-speed, heat engine which produces power in the 25 kilowatts to 500 kilowatts range, frequently by converting fluid energy into mechanical energy. These turbines are characterized by their small size, low vibration and noise, fuel flexibility, and ability to be used in distributed generation for electricity and heat (combined heat and power).
Micro-gears – These are small gears with dimensions typically less than 20 millimeters in diameter or with a module less than 200 micro-meters, fabricated using precision manufacturing techniques. They are necessary components in micro-mechanical systems for applications like micro-fluidics where they transmit motion and torque in a miniaturized format.
Micro-generation – It consists of small-scale electric power production to provide the needs of a small building or individual consumer.
Micro-graph – It is a graphic reproduction of the surface of a sample at a magnification greater than 25×. If produced by photographic means it is called a photo-micrograph (not a micro-photograph).
Micro-grid – It is a local electrical network of distributed energy resources (DERs) like generators and storage systems, and loads, which acts as a single controllable entity and can operate independently in ‘island mode’ or connected to the main utility grid. It is designed to provide reliable, clean, and economic power to a defined area, such as a campus, or industrial park, by managing its own generation, distribution, and storage.
Micro-grinding – It is a precision grinding process which uses extremely fine abrasive (50 micro-meters and finer).
Micro-gripper – It is a micro-electro-mechanical system (MEMS) device designed to grasp and manipulate objects at the microscopic scale, frequently used in micro-assembly. It integrates components like jaws, an actuator (which can be electrostatic, piezoelectric, or thermal), and a sensor to perform precise pick-and-place operations on micro-objects.
Micro-groove – It is a precisely fabricated, narrow channel or groove with dimensions in the micro-meter range, used in applications like micro-fluidics, and micro-electro-mechanical systems. They are engineered to leverage principles like capillary action for liquid transport or to influence the behaviour of materials, such as alignment or reducing friction and wear in mechanical components.
Micro-hardness – It is the hardness of a material as determined by forcing an indenter such as a Vickers or Knoop indenter into the surface of a material under very light load, Normally, the indentations are so small that they are to be measured with a microscope. It is capable of determining hardnesses of different micro-constituents within a structure, or of measuring steep hardness gradients such as those encountered in case hardening.
Micro-hardness number – It is a commonly used term for the more technically correct term micro-indentation hardness number.
Micro-hardness test – It is a microscopic method for determining a material’s hardness by pressing a diamond indenter into its surface with a specific load. The hardness is calculated by measuring the size of the resulting indentation and dividing the applied force by the indentation’s surface area. Common methods include Vickers and Knoop, and this technique is ideal for thin materials, thin films, and individual microscopic features where macro-hardness testing causes failure.
Micro-indentation – In hardness testing, it is the small residual impression left in a solid surface when an indenter, typically a pyramidal diamond stylus, is withdrawn after penetrating the surface. Typically, the dimensions of the micro-indentations are measured to determine micro-indentation hardness number, but newer methods measure the displacement of the indenter during the indentation process to use in the hardness calculation. The precise size needed to qualify as a ‘micro indentation’ has not been clearly defined. However, typical measurements of the diagonals of such impressions range from approximately 10 micrometers to 200 micrometers, depending on normal force and material.t is also the process of indenting a solid surface, using a hard stylus of prescribed geometry and under a slowly applied normal force, normally for the purpose of determining its micro-indentation hardness number.
Micro-indentation hardness number – It is a numerical quantity, normally stated in units of pressure (kilogram per square millimeter), which expresses the resistance to penetration of a solid surface by a hard indenter of prescribed geometry and under a specified, slowly applied normal force. The prefix ‘micro’ indicates that the indentations produced are typically between 10 micrometers and 200 micrometers across.
Micro-indentation hardness test – In a micro-indentation hardness test, a calibrated machine is used to force a diamond indenter of specific geometry, under a test load of 1 gram-force to 1,000 gram-force, into the surface of the test material and to measure the diagonal or diagonals optically. It is also known as micro-hardness test.
Micro- jet – It is a jet which has at least one dimension under 1 millimeter and can refer to different things such as a stream of fluid, or a specialized milling machine. In the fluid dynamics and scientific context, micro-jets are small, high-speed streams of fluid or bubbles generated by microscopic nozzles or created by laser-induced shock waves. It can also refer to the micro-jet grinding mill, a piece of industrial equipment.
Micro-lug – It is a test coupon used to evaluate the effectiveness of magnesium treatment in the production of ductile iron. The resulting micro-structure, viewed under a microscope, provides a rapid indication of the success of the treatment, which is crucial for achieving the desired mechanical properties in the finished product.
Micro-machined devices – These are defined as components produced from sheets of metal or slices of silicon which can function as micro-sensors or micro-actuators, frequently integrated with circuits to perform several tasks in mechanical and electronic systems. They are characterized by their ability to be manufactured in volume with cost effectiveness, facilitating the development of micro-electro-mechanical systems (MEMS) for diverse applications.
Micro-machining – It is a manufacturing process which removes material at the micro-scale to create highly precise components with feature sizes typically between 1 micrometer and 500 micrometers. Common techniques include photo-lithography and etching for semiconductors, LIGA (German acronym for Lithographie, Galvanoformung, and Abformung meaning lithography, electroplating, and moulding) for high-aspect-ratio parts, and different mechanical micro-machining methods for metals, plastics, and ceramics. This technology is essential for producing complex micro-scale parts for applications like micro-electro-mechanical systems (MEMS), medical devices, and other micro-electronics.
Micro-magnetics – It is a continuum theory used to describe the magnetic behaviour of materials at the micrometer to nanometer scale by treating magnetization as a continuous vector field. It is a computational field which models how magnetic materials respond to external fields and internal energies by solving equations for both static and dynamic behaviour, resolving features like magnetic domain walls without needing to simulate individual atoms. This allows for the simulation and design of magnetic devices in applications like data storage and sensors.
Micro-manometer – It is an instrument which operates on the manometer principle, designed to minimize capillary effects and meniscus reading errors, with high accuracy for pressure measurement, particularly useful as a calibration standard.
Micro-mechanical analysis – It is the study of heterogeneous materials, such as composites, at the level of their individual constituents (e.g., fibres and matrix) to predict the overall mechanical behaviour of the material. It uses the known properties of these constituent materials and their interactions to estimate the composite’s effective properties, like stiffness and strength, and understand phenomena like damage onset and propagation. This approach allows for the prediction of properties which can be difficult to measure experimentally.
Micro-mechanical properties – These properties refer to the characteristics of materials which are determined by the micro-mechanical processes of deformation and fracture, which link the material’s morphology to its mechanical properties. These properties can be directly visualized and characterized using techniques such as electron and scanning force microscopy.
Micro-mechanics – It consists of the analysis of the structural behaviour of composites on a constituent (matrix, reinforcement, and interface) level.
Micro-mechanism – It refer to a mechanical device with components smaller than one millimeter, or to the study of the mechanical behaviour of materials at a microscopic level. The former involves designing and fabricating tiny, functional mechanical systems, while the latter focuses on how the micro-scale structure of a material affects its overall properties.
Micro-mesh – It is a sieve with precisely square openings in the range of 10 micrometers to 120 micrometers produced by electro-forming.
Micro-mesh sizing – It is the process of sizing micro-mesh particles using an air or a liquid suspension process.
Micro-meter – It is also known as a micrometer screw gauge (MSG). It is a device incorporating a calibrated screw for accurate measurement of the size of components. Micrometers are normally, but not always, in the form of calipers (opposing ends joined by a frame). The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil. The spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil. Micrometer is also a unit of length in the International System of Units (SI) equaling 0.000001 metre, i.e., one millionth of a metre (or one thousandth of a millimeter.
Micro-milling process – It is a high-precision machining technique used for the fabrication of micro-sized features in different materials, aimed at creating accurate models and improving the tribological performance of components.
Micro-mixing performance – It refers to the efficiency of mixing at a micro-scale, which can considerably improve mass transfer and reduce mixing time, hence controlling processes such as crystallization and nano-particle synthesis. It is influenced by factors such as channel size and the introduction of external energy fields to achieve uniform and stable mixing environments.
Micro-motor – It is either a very small electric motor, or a self-propelled, microscopic particle which moves autonomously in a chemical solution. The electric motor version is a low-power, compact motor, frequently direct current-driven and used for precise control or power in miniaturized devices. The self-propelled version, sometimes called a nano-motor, is a synthetic machine which converts chemical energy into motion.
Micro-organisms (pathogens) – The pathogenic micro-organisms enter in to water body through sewage discharge as a major source or through the waste water from industries. Organic matter is described as bio-degradable if it is readily decomposed by the action of micro-organisms. The micro-organisms exist as a mixture of bacteria, fungi and Protozoa. In heavily polluted water, they are visible as pink, yellow, brown slimy growths which are frequently called ‘sewage funguses. The micro-organisms utilize pollutive organic compounds for their growth and nutrition and produce simple products, thereby reducing the amount of pollution. There are two types of metabolism, aerobic and anaerobic. Aerobic micro-organisms use oxygen to carry out oxidation reactions such as the (i) carbohydrates, phenols etc. are converted to carbon dioxide and water, (ii) organic nitrogen compounds are converted to carbon dioxide, water, amines and ammonia, (iii) organic sulphur compounds are converted to sulphides, and (iv) organic phosphorus compounds are converted to phosphates. Biodegradation of these compounds rapidly decreases the dissolved oxygen, and creates a biochemical oxygen demand in the polluted water. Heavily polluted water has little or no dissolved oxygen. Under these conditions only anaerobic micro-organisms can exist. Under anaerobic conditions, the anaerobic micro-organisms cause these reactions to occur namely (i) carbohydrates are converted into methane, (ii) organic sulphur compounds and sulphates are converted into sulphides, (iii) organic phosphorus compounds are converted to phosphine, (iv) organic nitrogen compounds are converted to nitrate, and then ammonia.
Micro palletization – It is also referred to as micro-pelletizing. It is an agglomeration technique which transforms fine, powdered materials into small, uniform, free-flowing pellets, typically ranging in size from 20 mesh to 60 mesh (around 0.85 millimeters to 0.25 millimeters in diameter). The main goal of micro-pelletizing is to process fine materials to make them easier and safer to handle, transport, and apply. This process is distinct from traditional, larger-scale pelletizing in that it produces much smaller, frequently denser, pellets.
Micro-phase separation – It is the spontaneous self-assembly of different polymer chains within a material into distinct nano-meter-scale domains. This happens since the polymer segments are chemically incompatible, but the covalent bonds between them prevent complete separation. The result is an ordered, nano-structured material, such as lamellar, cylindrical, or spherical structures, which can considerably influence the material’s overall properties.
Micro-phone – It is a transducer which changes sound into electrical signals.
Micro-photograph – It is an image, captured photographically or digitally, of the magnified microstructure of a metal sample as viewed through a microscope.
Micro-pipette – It is a precision laboratory instrument used to measure and transfer minuscule liquid volumes in the micro-litre range. Engineering principles are applied in their design for mechanical accuracy, ergonomics, and material durability to ensure precise, reliable, and reproducible handling of liquids in different applications.
Micro-pore – It consists of the pores in a sintered product which can only be detected under a microscope.
Micro-pore carbon block – It is a type of porous carbon material, characterized by having a large number of pores with diameters less than 2 nanometers. These micropores considerably increase the surface area of the carbon block, improving its capacity for adsorption and filtration. Micropore carbon blocks are frequently used in industrial applications like blast furnace linings, water filtration, and gas purification. In case of blast furnace, It is made from calcined anthracite under high temperature with other additives by extruding, baking and processing. Typical properties are better micro porosity, permeability, and anti-erosion from iron liquid. Micro-pore carbon block is used in lay hearth of blast furnace.
Micro-porosity – It is the extremely fine porosity in castings caused by shrinkage or gas evolution, apparent on radiographic film as mottling.
Micro-porous material – It is a material containing pores with diameters less than 2 nano meters. Examples of micro-porous materials include zeolites and metal-organic frameworks.
Micro-porous membrane – It is a thin structure with a precisely controlled interconnected network of tiny holes which are too small to allow water droplets to pass through but large enough to permit water vapour to pass. These membranes are typically made from polymers.
Micro-processor – It is a computer with its logical, arithmetic and control functions implemented on one or a few integrated circuits.
Micro-processor-based control – It is an advanced control system utilizing microprocessors for precise and automated process operation. Regular monitoring is necessary for software updates, functionality, and calibration.
Micro product – It refers to a minimal, highly focused digital product or a physical product with a small physical size, frequently in the millimeter or micrometer range. In a digital context, it is a product with just the most attractive features, designed for rapid delivery and market testing. In manufacturing, it is a product with very fine physical dimensions, created using micro-manufacturing techniques like micro-milling or 3D printing at a micro-scale.
Micro-pulverizer – It is a machine which disintegrates powder agglomerates by strong impacts from small hammers fastened to a solid disk which rotates at a very high velocity.
Micro-pump – It is a miniaturized device which transports or distributes small volumes of liquid, typically in the micrometer range. They are essential components in micro-fluidic systems and can be categorized as either mechanical (using moving parts like diaphragms or gears) or non-mechanical (using energy conversion, like electroosmotic flow). These pumps are important for applications like lab-on-a-chip devices, and chemical analysis because of their small size, accuracy, and ability to manipulate tiny fluid quantities.
Micro-radiography – It is an imaging technique which uses low-energy X-rays to reveal the fine internal structure of a material sample. It is mainly a diagnostic tool for viewing features and flaws in opaque materials, such as alloys, which cannot be seen with a traditional light microscope.
Micro-reactor – It is a device where reactions take place in channels with dimensions typically less than 1 millimeter, offering advantages like precise temperature control and improved heat and mass transfer because of a high surface-area-to-volume ratio. In nuclear engineering, a micro-reactor is a compact, transportable nuclear fission reactor designed to produce 1 megawatt to 20 megawatts of power for different applications, including providing electricity to remote areas or industrial sites.
Micro-roughness – It refers to the fine, microscopic irregularities on a surface, characterized by small-scale peaks and valleys with a feature length typically between 1 micrometer and 10 micrometers. This microscopic texture is a component of the overall surface texture and considerably affects the surface’s physical properties, such as friction, wear, and adhesion. Processes like plasma spraying, acid etching, and blasting are used to create micro-roughness on materials.
Micro-scale – It refers to objects and phenomena occurring at a size typically between 100 and 100 . It describes miniaturized components and systems, like those used in micro-electro-mechanical systems (MEMS) for applications such as sensors, and it also describes the length scale of physical processes, such as heat transfer in microchannels or the smallest eddies in turbulent flow.
Microscope – It is a laboratory instrument used to examine objects which are too small to be seen by the naked eye. A microscope is capable of producing a magnified image of a small object. There are several types of microscopes, and they can be grouped in different ways.
Microscopic – It means being invisible to the eye unless aided by a microscope. It is visible at magnifications above 25×.
Microscopic cross-section – It is a measure of the probability that an incident particle interacts with a single nucleus in a material. It is defined as an effective ‘target area’ for a nucleus, with units of area, such as barns (10 to the power -24 square centimeter. This value quantifies the likelihood of a specific reaction and is dependent on the type of particle, its energy, and the target material.
Microscopic morphology – It is the study of the size, shape, and structure of a material’s internal components at a microscopic level, such as grains, phases, pores, and cracks. It is an important aspect of materials science since a material’s microscopic structure fundamentally influences its physical and chemical properties and performance. This analysis is performed using different microscopy techniques, including electron and optical microscopes.
Microscopic scale – It refers to the level of detail where objects and events are too small to be seen with the naked eye and need magnification, such as with a microscope. It is the scale of individual components like atoms, molecules, particles, and their contacts, where engineering analysis frequently involves specific properties, mechanical laws, and numerical simulations like the ‘discrete element method’ (DEM). This differs from the macroscopic scale, which deals with larger, human-sized objects and their overall behaviour.
Microscopic stresses – These are also called micro-stresses. These are scalar properties of the sample, such as percent of cold work or hardness, that are without direction and result from imperfections in the crystal lattice. Micro-stresses are associated with strains within the crystal lattice which traverse distances on the order of or less than the dimensions of the crystals. Micro-stresses vary from point to point within the crystal lattice, altering the lattice spacing and broadening the diffraction peak. Micro-stresses can be determined from the X-ray diffraction-peak position and breadth. Microscopic stress is the residual stress in a material within a distance comparable to the grain size.
Microscopy – It is the science of investigating small objects and structures using a microscope.
Micro-scratches – These are tiny, frequently microscopic abrasions on a surface which are typically invisible to the naked eye under normal light but become visible under certain conditions, such as bright or direct light. They are a form of surface damage which can make a surface appear dull and are caused by the accumulation of several tiny scratches from everyday activities.
Micro-second – It refers to a unit of time defined as one millionth of a second.
Micro-section – It is a small, prepared sample of a metal or alloy which is used for microscopic examination to analyze the material’s internal structure, or microstructure. This is also known as a cross-section or metallographic preparation. The analysis provides important information about the material’s physical and mechanical properties.
Micro-segregation – All metallic materials contain solute elements or impurities which are randomly distributed during solidification. The variable distribution of chemical composition on the microscopic level in a microstructure, such as dendrites and grains, is referred to as micro-segregation. It is the segregation within a grain, crystal, or small particle. Since the micro-segregations normally deteriorate the physical and chemical properties of materials, they are to be kept to a minimum.
Micro-sensor – It is a miniaturized device, frequently a component of a micro-electro-mechanical system (MEMS), designed to detect and convert physical, or chemical parameters from its environment into measurable electrical signals. These devices typically have dimensions ranging from micro-meters to a few millimeters.
Micro-separation – It is a field of technology and engineering which utilizes micro-structured equipment units (with dimensions between sub-millimeters and sub-microns) to perform classical unit operations such as extraction, distillation, and absorption.
Micro-shrinkage – It is a casting imperfection, not detectable microspically, consisting of inter-dendritic voids. Micro-shrinkage results from contraction during solidification where the opportunity to supply filler material is inadequate to compensate for shrinkage. Alloys with wide ranges in solidification temperature are particularly susceptible.
Micro-shrinkage cavities – Micro-shrinkage cavities are aggregates of sub-surface discontinuities which are found in the cast materials. These cavities are normally found in the foundry castings close to the gate. These cavities occur if metal at the gate solidifies while some of the metal beneath is still liquid. Also, micro-shrinkage can be found deeper in the part when the liquid metal enters from the light section into heavy section where metal can solidify in the light section before the heavy section.
Micro-slip – It is small relative tangential displacement in a contacting area at an interface, when the remainder of the interface in the contacting area is not relatively displaced tangentially. Micro-slip can occur in both rolling and stationary contacts. The term micro-slip is sometimes used to denote the micro-slip velocity. This usage is not recommended.
Micro, small, and medium enterprises – These enterprises are defined based on investment in plant / machinery or equipment and annual turnover.
Micro-spectroscopy – It is a technique which combines a microscope with a spectrometer to perform chemical and structural analysis on microscopic areas of a metallic sample. It provides a detailed, spatially resolved chemical map of the microstructure, giving metallurgists critical information which cannot be obtained with conventional, bulk-analysis methods.
Micro-strain – It is the strain over a gauge length comparable to inter-atomic distances. These are the strains being averaged by the macro-strain measurement. Micro-strain is not measurable by existing techniques. Variance of the micro-strain distribution can, however, be measured by X-ray diffraction.
Micro-strainer – It is a physical filtration device which uses a finely woven screen, frequently on a rotating drum, to remove suspended solids, algae, and plankton from liquids. It is used in applications like water and wastewater treatment for preliminary or tertiary treatment, as well as in other industries to protect equipment from clogging by removing fine particles.
Micro-stress – It is the residual stress in a material within a distance comparable to the grain size.
Micro-strip – It is a planar transmission line which is fabricated by printed circuit board technology and which is used for micro-wave-frequency signals.
Micro-strip antenna -It is a planar antenna which is fabricated by printed circuit board technology.
Micro-structure – It is a structure with heterogeneities which can be seen through a microscope. it is the structure of an object, organism, of material as revealed by a microscope at magnifications higher than 25×. The micro-structure of ferrous alloys is a basic tenet of physical metallurgy. The composition and processing establish the micro-structure and the micro-structure influences several properties and service behaviour of steel. For maintaining control of the quality of steel products and to diagnose problems in processing, testing, or service, the micro-structure is to be identified first and, in some cases, quantified.
Micro-structure monitoring – A decisive criterion for the quality of hot rolled strip is whether it lies within the tolerance range specified by the customer for tensile and yield strength. To document this quality, the rolling mill operator has traditionally been forced to subject samples taken from ongoing production to an extensive (and expensive) series of tests. This testing not only slows down production speed but can also provide unreliable results depending on the intervals between the samples. The solution to overcome these shortcomings, a new ‘Micro-structure Monitor’ system is used, now determines these quality parameters online during the production process, hence reducing the need for costly laboratory measurements and the time needed to conclude those tests. Additionally, the ‘Micro-structure Monitor’ enables process parameters, such as coiling temperature, to be optimized with regard to target mechanical values.
Micro-system – It is a miniaturized system that integrates components like sensors, actuators, and micro-electronics to perform specific functions, with characteristic dimensions in the micrometer to millimeter range. These systems, often referred to as MEMS (micro-electro-mechanical systems), combine multiple disciplines such as electronics, mechanics, optics, and chemistry to create intelligent, highly integrated solutions for several applications.
Micro-technology engineering – It is the design, fabrication, and integration of miniature devices and systems with dimensions in the micrometer range (1 micrometer to 1000 micrometers). This multi-disciplinary field combines mechanical, electronic, materials, and physics engineering to create functional components like micro-electronics, micro-electro-mechanical systems (MEMS), and micro-fluidic devices for several applications.
Micro-tester – It is a specialized instrument used to measure the mechanical properties of materials on a microscopic scale, frequently through a technique called micro-hardness testing. This differs from macro-hardness testing, which uses larger samples and heavier loads.
Micro-throwing power – It is the ability of a plating solution or a specified set of plating conditions to deposit metal in pores or scratches.
Micro-tone – It is an instrument for cutting thin sections of soft samples.
Micro-turbine – It is a small-scale gas turbine which generates electricity, typically ranging from 25 kilowatts to 250 kilowatts, by burning gaseous or liquid fuels. Characterized by their compact size, high rotational speeds, and ability to run on different fuels like natural gas, propane, or biogas, they are used for distributed generation and can achieve high overall efficiencies (up to 85 %) when used for combined heat and power (CHP).
Micro-void – It is a microscopic void or cavity within a material, formed during manufacturing or service life. These voids can appear in a variety of materials, including composites, metals, and solder joints, and can negatively impact mechanical properties like strength and reliability. They are a critical factor in the performance of engineered components, influencing processes such as material fracture and material flow during composite manufacturing.
Micro-void coalescence (MVC) – It is the ductile micro-mechanism of fracture which occurs because of the nucleation of microscale voids, followed by their growth and eventual coalescence. Initiation is caused by particle cracking or interfacial failure between an inclusion or precipitate particle and the surrounding matrix.
Micro-void coalescence (MVC) – It is a fracture mechanism, particularly common in ductile materials, where small voids or cavities within the material combine and grow together, eventually leading to the material’s failure. This process is a crucial step in ductile fracture, following void nucleation and growth.
Micro-wave – It is a part of the radio spectrum with wavelengths shorter than 100 millimeters.
Micro-wave heating – It is a volumetric process which uses electromagnetic waves to generate heat directly within a material, rather than from an external source. This occurs through the interaction of the microwaves with the material’s polar molecules, which rotate and cause friction, and mobile ions, which move rapidly. This internal heating mechanism allows for rapid and selective heating, which can reduce processing times and improve energy efficiency in applications like chemical synthesis, drying, and material sintering.
Micro-wave oven – It is a heating appliance which uses micro-wave energy.
Micro-wave pyrolysis – It is an engineering process which uses microwave energy to heat organic materials, like biomass or waste plastics, in an oxygen-free environment to decompose them into valuable products such as bio-oil, gas, and char. It is considered a more efficient, rapid, and controllable method compared to conventional pyrolysis since the microwaves directly heat the material internally, leading to faster and more uniform heating rates.
Micro-wave radiation – It consists of electro-magnetic radiation in the wave-length range of 0.3 millimeters to 1 metre (3 million angstrom to I billion angstrom).
Micro-wave radio -It is the sub-set of radio technique using wave-lengths which are in the range of 3 giga-hertz or higher.
Micro-wave sintering – It is a heating process in which a composite absorbs electromagnetic radiation, generating heat internally and distributing it throughout the material. This method is distinguished from traditional sintering techniques by its fast-heating rates, lower sintering temperatures, and improved physical and mechanical properties.
Micro-wave technique – This inspection technique is fairly new in its concept and whilst it has been applied in a few very specific applications in a laboratory environment. The proposed application of the technique to in-line inspection of the billets in a steel plant is thought to be unique. The detector can be mounted some tens of millimeters away from the billet surface and that must be of benefit since it reduces its susceptibility to mechanical damage. The inspection area is, however, relatively large and therefore one is to expect that it is responsive only to large area defects or to cracks of either longitudinal or transverse orientation. This form of detector shows enough merit to be considered but the capital cost of each detector head is high.
Micum index – The coke mechanical strength are indicated as micum 10 (M10) and micum 40 (M40) which are indices of resistance to abrasion and fragmentation, respectively.
Micum / Irsid test – In it a representative sample of +25 mm ‘round hole’ coke is placed in the specified tumbler drum and rotated for 100 revolutions. The coke is removed, screened and replaced in the drum and subjected to a further 400 revolutions in the drum. The test is based on the international standard ISO 556. The values reported are (i) M40 value which is the percentage of coke remaining on the +40 mm ‘round hole screen’ after 100 revolutions, (ii) M10 value which is the -10 mm ‘round hole screen’ coke after 100 revolutions, (iii) I20 value which is the percentage of coke remaining on the +20 mm ‘round hole screen’ after 500 revolutions, and (iv) I10 value which is the -10 mm ‘round hole screen’ coke after 500 revolutions. Larger values of M40 and I20 and smaller value of M10 and I10 normally indicate coke with higher strength.
Middle-infrared radiation – It consists of infrared radiation in the wave-length range of 3 micrometers to 30 micrometers (30,000 angstroms to 300,000 angstroms).
Middling – It is a product intermediate between concentrate and tailing and containing enough of a valuable mineral to make retreatment economical.
Mid-hinge – In statistics, it is the average of the first and third quartiles and is hence is a measure of location. Equivalently, it is the 25 % trimmed mid-range or 25 % mid–summary, it is an L-estimator. MH(X)=Q1,3(X)¯=Q1(X)+Q3(X)2=P25(X)+P75(X)2=M25(X)The midhinge is related to the interquartile range (IQR), the difference of the third and first quartiles, which is a measure of statistical dispersion. The two are complementary in sense that if one knows the midhinge and the interquartile range, one can find the first and third quartiles.
Mid-Infrared (MIR) spectroscopy – It is an analytical technique which uses infrared light in the 2.525 micrometer range (4,000,400 per centimeter) to determine the molecular composition and structure of a sample. By measuring the absorption of this specific wave-length of light, it identifies and analyzes functional groups within materials like solids, liquids, and gases by observing how their chemical bonds vibrate and absorb energy.
Mid-range – In statistics, the mid-range is a measure of central tendency of a sample and is defined as the arithmetic mean of the maximum and minimum values of the data set. It The mid-range is closely related to the range, a measure of statistical dispersion defined as the difference between maximum and minimum values. The two measures are complementary in sense that if one knows the mid-range and the range, one can find the sample maximum and minimum values.
Midrex process – It is an ironmaking process, developed for the production of direct reduced iron (DRI). It is a gas-based shaft furnace process is a solid-state reduction process which reduces iron ore pellets or lump ore into direct reduced iron without their melting using reducing gas normally formed from natural gas. The process involves three major unit operations namely (i) iron ore reduction, (ii) gas preheating, and (iii) natural gas reforming. The heart of the Midrex process is its shaft furnace. It is a cylindrical, refractory-lined vessel and is a key component of the direct reduction process. It is flexible as well as a versatile reactor. It can use natural gas, a syngas from coal, coke oven gas, or exhaust gas from Corex process as the reducing gas. It operates at slightly above atmospheric pressure and at operating temperatures which are around 950 deg C.
MIG welding – It is metal inert-gas welding. It is a non-standard term for flux cored arc welding and gas metal arc welding.
Migmatite – It is the rock which consists of thin, alternating layers of granite and schist.
Migration – It normally refers to the process of moving a system or data from one environment to another, frequently with the goal of upgrading, improving, or optimizing the system. This can involve moving applications, databases, or infrastructure, and can need changes to the data format or structure.
Mike mark – It is a narrow continuous line near the rolled edge caused by a contacting micro-meter.
Mil – It is one thousandth of an inch 0.001 which is equal to 25.4 micrometers. It is a unit of length used in measuring the diameter of glass fiber strands, wire, and so on.
Mild steel – It is carbon steel with a maximum of around 0.25 % carbon and containing 0.4 % to 0.7 % manganese, 0.1 % to 0.5% silicon, and some residuals of sulphur, phosphorus, and / or other elements. Mild steel has properties which are suitable for most general engineering applications. Because of its high iron content, mild steel has excellent magnetic properties, it is hence defined as being ‘ferromagnetic’. It has a relatively higher melting point between 1,450 deg C to 1,520 deg C. This melting point means that mild steel is more ductile when heated, making it especially suitable for drilling, cutting, forging, and welding, hence easy to fabricate.
Mild wear – It is a form of wear which is characterized by the removal of material in very small fragments. Mild wear is an imprecise term, frequently used in research, and contrasted with severe wear. In fact, the phenomena studied normally involve the transition from mild to severe wear and the factors which influence this transition. Mild wear can be appreciably higher than can be tolerated in practice. With metallic sliders, mild wear debris normally consists of oxide particles.
Mile – It is a British imperial unit and United States customary unit of length. Both are based on the older English unit of length equal to 5,280 English feet, or 1,760 yards. The yard has been formally redefined with respect to SI units as 0.9144 meters, making the mile exactly 1609.344 meters (1.609344 kilometres). For everyday use, five miles equates roughly to eight kilometres.
Milk of lime – It is also known as lime milk or lime slurry. It is a suspension of calcium hydroxide [Ca(OH)2] particles in water. It is a highly alkaline (basic) material (pH around 12.5) with a large number of industrial uses, as well as health and safety considerations.
Mill – It is a plant in which in which ore is treated and metals are recovered or prepared for smelting and also in which metals are hot worked, cold worked, or melted and cast into standard shapes suitable for secondary fabrication into commercial products. It is also a production line, normally of four or more stands, for hot or cold rolling metal standard shapes such as bar, rod, plate, sheet, or strip. It is also a single machine or hot rolling, cold rolling, or extruding metal. Examples include blooming mill, cluster mill, four-high mill, and Sendzimir mill. It is also a shop term for a milling cutter. It is also a machine or group of machines for grinding or crushing ores and other minerals. It is also a machine for grinding or mixing material, e.g., a ball mill, and a revolving drum used for the grinding of ores in preparation for treatment. It also consists of grinding or mixing a material, e.g., milling a powder metallurgy material. Common mills for the preparation of a powder are ball mill, hammer mill, disk mill, roll mill, vortex mill rod mill, and impact mill.
Mill addition – It is a material which is added to the ball milling charge of a frit.
Mill certificate – It is the test certificates provided by the steel mill indicating the chemical analysis and physical properties of a specific batch of steel.
Mill charge – It is the total quantity of material inside a grinding mill, consisting of both the material being ground and the grinding media, such as steel balls or rods. The composition, volume, and motion of the mill charge are critical for the efficiency of the grinding process and are optimized by adjusting the ratio of grinding media to ore and the mill’s speed.
Milled fibre – It is continuous glass strands which are hammer milled into very glass fibres. These are useful as inexpensive filler or anti-crazing reinforcing fillers for adhesives.
Mill edge – It is the normal edge produced in hot rolling of sheet metal. This edge is customarily removed when hot rolled sheets are further processed into cold rolled sheets.
Milled material – It is a substance which has been reduced to a finer powder or particle size through the process of milling, which can involve grinding, crushing, or cutting. The purpose of milling is to prepare plant materials for chemical extraction or machining metal into a specific shape.
Miller-Bravais indices – These are the indices used for the hexagonal system. They involve use of a fourth axis, ‘a3’, coplanar with and at 120-degree to ‘a1’ and ‘a2’.
Miller indices – It is a system for identifying planes and directions in any crystal system by means of sets of integers. The indices of a plane are related to the intercepts of that plane with the axes of a unit cell. It is the indices of a direction, to the multiples of lattice parameter which that represent the coordinates of a point on a line parallel to the direction and passing through the arbitrarily chosen origin of a unit cell.
Miller indices (for lattice planes) – These are the reciprocals of the fractional intercepts a plane makes on the three axes. The symbols are (hkl).
Miller number – It is a measure of slurry abrasivity as related to the instantaneous mass-loss rate of a standard metal wear block at a specific time on the cumulative abrasion-corrosion time curve.
Miller timing – It is a valve timing modification in internal combustion engines which involves leaving the intake valve open longer into the compression stroke. This allows some of the air-fuel mixture to be pushed back into the intake manifold, shortening the effective compression stroke while the expansion stroke remains longer. This technique improves thermal efficiency and reduces emissions by lowering compression and peak combustion temperatures.
Mill finish – It is a non-standard (and typically non-uniform) surface finish on mill products which are delivered without being subjected to a special surface treatment (other than a corrosion-preventive treatment) after the final working or heat-treating step.
Mill, grinding – Grinding mills are size reductions machines which frequently follow crushers in the processes where finer products are desired after crushing. Different grinding machines are normally named as mills, for example rod mills, ball mills, and attrition mills. Because of the name, verb milling is also been used as a synonym for grinding. A wide range of mills has been developed each for particular applications. Some types of mills can be used to grind a large variety of materials whereas others are used for certain specific grinding requirements.
Milligrams per litre – It is a unit of measurement which expresses a concentration, i.e., the mass (weight) of one material dissolved into a volume of another material.
Milling – It is sometimes also known as fine grinding, pulverizing or comminution. It is the process of reducing materials to a powder of fine or very fine size. It is distinct from crushing or granulation, which involves size reduction of a material to a smaller size. Milling is used to produce a variety of materials which either have end uses themselves or are raw materials or additives used in the manufacture of other products. Milling is also a machining process which is used to create features such as holes, cavities, threads, and surfaces through cutting operations, which can involve the application of coolants to manage temperature and improve tool performance.
Milling circuit – It can be either open or closed. The milling circuit is the complete mill system from beginning to end, which includes feed mechanism, mill, classifier, separator, product collector, etc. In a closed mill circuit, the oversize particles are returned from the post milling processes to be regrinding, while in an open circuit the process there is no feedback loop.
Milling cutter – It is a rotary cutting tool which is provided with one or more cutting elements, called teeth, which intermittently engage the work-piece and remove material by relative movement of the work-piece and cutter.
Milling fluid, milling liquid – It is an organic liquid, such as hexane, in which ball milling is carried out. The liquid serves to reduce the heat of friction and resulting surface oxidation of the particles during grinding, and to provide protection from other surface contamination.
Milling machine – It is a power-driven machine tool which uses rotating cutters to remove material from a work-piece, shaping it to desired dimensions and forms. It is a versatile machine capable of producing different features like flat surfaces, slots, and even gears.
Milling, machining – It means removal of metal with a milling cutter.
Milling ore – It is the ore which contains sufficient valuable mineral to be treated by milling process.
Milling, powder technology – It is the mechanical comminution of a material, normally in a ball mill, to alter the size or shape of the individual particles, to coat one component of a mixture with another, or to create uniform distributions of components.
Milling technique – It is the process of breaking down relatively coarse materials to achieve fine particle sizes, frequently using rotating cylindrical vessels containing loose balls, and is utilized in several applications including the separation of valuable minerals from gangue and preparation of ultrafine powders.
Milling temperature – It is a critical parameter in the ball milling process which influences the structure and properties of the end product, where higher temperatures can improve solid-state reactions and promote the formation of metastable phases.
Million metric standard cubic metre (MMSCM) – It is the term which is used to designate gas volume and gas flow rates in pipelines (MMSCM per hour or MMSCM per day).
Million tons per annum – It is a unit of measurement which quantifies the mass of a material produced or processed in millions of tons over the course of one year.
Milli-roentgen – It is one-thousandth of a roentgen (R), a legacy unit of measurement for exposure to X-rays and gamma rays. The concept is used in metallurgy for industrial radiography, a non-destructive testing method which examines the internal structure of metal parts and welds for flaws.
Milli-scope – It is an instrument which gives an electrical warning when melt reaches a pre-determined temperature.
Milli-volts – It is a unit of electric potential equal to one thousandth of a volt.
Mill lacquer – It is the organic protective coating applied to steel parts, normally pipes or tubes, to protect the parts during shipping. This material cannot be removed by the normal galvanized cleaning methods.
Millman’s theorem – It is a theorem stating the relation between branch currents and voltages for multiple sources in parallel.
Mill product – It is a commercial product of a rolling mill.
Mill protection devices – These devices ensure that the forces applied to the roll chocks are not of such a magnitude to fracture the roll necks or damage the housing.
Mill scale – It is the flaky surface of hot worked steel and is formed by the oxidation of the steel surface during reheating, conditioning, hot rolling, and hot forming operations. It is one of the wastes generated in steel plants and represents around 2 % of the produced steel. It is a hard brittle coating of several distinct layers of iron oxides formed during the processing of steel and composed mainly of iron oxides and can contain varying quantities of other oxides and spinels, elements and trace compounds. It flakes off the steel easily. Mill scale is normally present on rolled steel and is frequently mistaken for a blue-coloured primer. The very high surface temperature combined with high rolling pressures result in a smooth, bluish grey surface. Under visual inspection, mill scale appears as a black metal powder made up of small particles and chips. Its physical state is solid and powdered. The specific gravity of mill scale is in the range of 5.7 to 6.2. Mill scale’s melting point is around 1,370 deg C and boiling point is around 2,760 deg C. It has a stable state and is insoluble in water and alkalis but soluble in most of strong acids. It is normally classified as non- dangerous waste material.
Mill scale powder – It consists of pulverized iron oxide scale which is a by-product of hot working of steel (e.g., rolling, and forging). The material is readily reduced to a soft spongy iron powder free of mineral inclusions and other solid impurities.
Mill stars – These are multi-pointed white iron or hard iron bodies used in a tumbling barrel to assist in polishing and cleaning.
Mill test reports – These test reports normally indicate the chemical analysis and physical properties of a specific batch of steel.
Mill tests – These consist of all the tests which are required by the material specification and which normally include both the heat analysis (chemical) and the physical properties.
Minable reserves – It consists of ore reserves which are known to be extractable using a given mining plan.
Mine – It is a site, either underground or open-pit, where valuable minerals, rocks, or ores are extracted from the earth. This can include anything from metallic ores like gold and silver to non-metallic resources like coal, salt, and diamonds
Mine car – It is a vehicle, frequently a small wagon or cart, which runs on rails inside a mine to transport materials like ore, coal, rock, or waste from the work area to a processing facility. These cars are a fundamental part of mining operations, used to haul extracted materials to the surface or to the bottom of the mine. They are typically pulled or pushed by locomotives or other machinery, but can also be manually trammed in smaller mines.
Mine explosion – It is a sudden, violent event in an underground mine caused by the ignition of a mixture of flammable gas (like methane) and / or combustible dust (like coal dust) with air. The ignition, frequently from a spark or flame, creates a rapid release of energy and a pressure wave which can travel through the mine, causing fatalities and destruction.
Mine fire – It is a smoldering or flaming fire in a mine, frequently underground, caused by ignition of combustible materials like coal, wood, or electrical equipment. They are dangerous events which can produce toxic gases, threaten worker safety, and cause substantial economic and environmental damage. Mine fires are frequently started by factors like self-heating of coal (spontaneous combustion), electrical malfunctions, and external sources of heat.
Mine flooding – It is the accumulation of water in a mine, which can be caused by the failure of dewatering systems after a mine closes or by the influx of water from rainfall, groundwater, or nearby water bodies into an active mine. This excess water can hinder or stop mining operations, cause safety hazards, damage equipment, and sometimes lead to the permanent abandonment of a mine if the inflow cannot be controlled.
Mine locomotive – It is a specialized vehicle designed for underground mines to transport materials, equipment, and personnel along narrow-gauge tracks. These locomotives can be powered by different methods, including diesel engines, batteries, or overhead trolley wires, and are built low to navigate confined spaces and steep gradients. They are a crucial part of modern mining operations, replacing older methods and improving efficiency and safety.
Mine plan – It is a comprehensive, strategic document which outlines the entire mining operation, from design and scheduling to financial projections. It details how a mineral deposit is going to be extracted to ensure the operation is safe, profitable, and sustainable over its life of mine. The plan includes geological data, mining methods, equipment, production forecasts, safety and environmental considerations, and financial budgets, acting as a roadmap for the mine’s development and day-to-day activities.
Mineral – It is a naturally occurring homogeneous substance having definite physical properties and chemical composition and, if formed under favourable conditions, a definite crystal form.
Mineral acid – It is also known as inorganic acid. It is an acid derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds. All mineral acids form hydrogen ions and the conjugate base when dissolved in water. Commonly used mineral acids are sulphuric acid (H2SO4), hydrochloric acid (HCl), and nitric acid (HNO3). These are also known as bench acids. Mineral acids range from super-acids (such as perchloric acid) to very weak ones (such as boric acid). Mineral acids tend to be very soluble in water and insoluble in organic solvents.
Mineral dressing – It is the physical and chemical concentration of raw ore into a product from which a metal can be recovered at a profit.
Mineral exploration – It is the process of searching for economically viable concentrations of minerals, which can include metals, industrial materials, and gemstones. It involves a range of activities from initial prospecting and remote sensing to detailed drilling and analysis to determine the deposit’s size, quality, and potential for profitable mining. The goal is to identify a commercial ore body before actual mining operations begin, although several exploration projects do not result in a mine.
Mineral-filled moulding compounds – These are polymer-based composite materials created by blending a base polymer (thermoplastic or thermosetting resin) with different natural or synthetic mineral fillers. The main purpose of adding these fillers is to modify the compound’s properties and / or reduce production costs.
Mineral-insulated copper-clad cable – It is a cable with an outer metal cover and insulated by powdered inorganic material, suitable for high temperature. It is one kind of fire-resistant cable.
Mineralized material – Mineralized material is the projection of mineralization in rock based on geological evidence and assumed continuity. It may or may not be supported by sampling but is supported by geological, geochemical, geophysical or other data. This material may or may not have economically recoverable mineralization.
Mineralizer – The purpose of a mineralizer is to facilitate the transport of insoluble ‘nutrient’ to a seed crystal by means of a reversible chemical reaction. Over time, the seed crystal accumulates the material which has been once in the nutrient and grows. Mineralizers are additives which aid the solubilization of the nutrient solid. When used in small quantities, mineralizers function as catalysts. Typically, a more stable solid is crystallized from a solution which consists of a less stable solid and a solvent. The process is done by dissolution-precipitation or crystallization process.
Mineral matter – It is the inorganic, naturally occurring solid material found in the earth’s crust, with a consistent chemical composition and a specific crystal structure. It is the main component of rocks and soils, but the term can also refer to any inorganic substance, or even specific inorganic compounds found within organic materials like coal.
Mineral matter, coal – It is defined as all inorganic, non-combustible material which is in or associated with coal which include discrete crystalline mineral particles, dissolved ions and other inorganic components in the pore water or surface water of the coal, and inorganic elements combined within the organic compounds of the coal macerals. The minerals existing in coal are a result of processes which occur throughout the entire history of coal formation. Its distribution is influenced by biological, hydrological and geochemical factors. Quartz and the clay minerals are the most widespread and abundant mineral found in coal. Other common minerals are feldspars and carbonate in the form of siderite, calcite and dolomite and sulphide minerals such as pyrite. Mineral matter can play a catalytic role which influences the decomposition of the coal and can also influence the reactivity of the resulting coke.
Mineral occurrence – A Mineral occurrence is an indication of mineralization, that is worthy of further investigation. The term Mineral occurrence does not imply any measure of volume / tonnage or grade / quality and hence is not part of a Mineral resource.
Mineralogical composition and crystal formation – The behaviour of refractories of identical composition also depends on the type of raw materials used and on the reactions achieved during firing of the bricks. A glassy phase is more susceptible to attack by slag than a tightly interlocked crystal lattice structure. Two methods are used to identify mineralization composition. In the first method polarizing microscope or scanning electron microscope (SEM) is used. In the second method X-ray diffraction analysis is done.
Mineral oil – It is a liquid obtained from refining crude oil to make gasoline and other petroleum products. Mineral oils used for lubrication are known specifically as base oils. More generally, mineral oil is a transparent, colourless oil, composed mainly of alkanes and cycloalkanes, related to petroleum jelly. It has a density of around 0.8 grams per cubic centimeter to 0.87 grams per cubic centimeter. Mineral oil is a liquid mixture of hydrocarbons obtained from petroleum by intensive treatment with sulphuric and oleum, or by hydrogenation, or a combination, and consisting predominantly of saturated C15-C50 hydrocarbons.
Mineral oil based hydraulic fluids – These fluids have a mineral oil base. These fluids have high performance at lower cost. These mineral oils are further classified as HH, HL and HM fluids. Type HH fluids are refined mineral oil fluids which do not have any additives. These fluids are able to transfer power but have lesser properties of lubrication and unable to withstand high temperature. These types of fluid have a limited usage in industries. Some of the uses are manually used jacks and pumps, and low-pressure hydraulic system etc. Type HL fluids are refined mineral oils which contain oxidants and rust inhibitors which help the system to be protected from chemical attack and water contamination. These fluids are mainly used in piston pump applications. HM is a version of HL type fluids which have improved anti-wear additives. These fluids use phosphorus, zinc, and sulphur components to get their anti-wear properties. These are the fluids mainly used in the high-pressure hydraulic system. Mineral origin refers to the natural processes that form minerals, which are inorganic substances with a definite chemical composition and crystalline structure. Key origins include crystallization from cooling magma, precipitation from hot fluids or evaporated water, and changes to existing rocks from heat and pressure.
Mineral origin – It refers to the natural processes which form minerals, which are inorganic substances with a definite chemical composition and crystalline structure. Key origins include crystallization from cooling magma, precipitation from hot fluids or evaporated water, and changes to existing rocks from heat and pressure.
Mineral particles – These are tiny fragments of naturally occurring inorganic solids, like quartz or clay, which come from the erosion and weathering of rocks. Their size, shape, and composition determine several physical properties of materials like soil and sediment, and they are essential components of the earth’s crust.
Mineral processing – It is the process of separating commercially valuable minerals from their ores in the field of extractive metallurgy. Depending on the processes used in each case, it is frequently referred to as ore dressing or ore milling.
Mineral products – Products of a mineral project can be foreseeably bought, sold or used, and can include (i) mined or produced ores, (ii) co-products, (iii) beneficiated ores, (iv) processed ore concentrates, and (v) by-products.
Mineral project – A mineral project produces mineral products from a mineral source with defined frame conditions, which provide the basis for environmental-socio-economic evaluation and decision-making. A mineral project is comprised of a defined activity or set of activities, which provide the basis for estimating environmental-socio-economic viability including costs and potential revenues associated with its implementation.
Mineral recovery – It is the process of extracting valuable minerals from ore or waste materials, using different physical and chemical techniques to separate and concentrate the desired minerals from the rest of the material. This can involve traditional mining from primary deposits or modern recycling from secondary sources like electronic waste or tailings, with the goal of maximizing yield, improving efficiency, and achieving resource sustainability.
Mineral reserve – It is the economically mineable part of a measured or indicated mineral resource demonstrated by at least a preliminary feasibility study. This study is to include adequate information on mining, processing, metallurgical, economic and other relevant factors which demonstrate, at the time of reporting, that economic extraction can be justified. A mineral reserve includes diluting materials and allowances for losses that may occur when the material is mined. It includes (i) Proved Mineral reserves, which include ‘Economically mineable part of Measured Mineral resource’, and (ii) Probable Mineral reserves which include ‘Economically mineable part of indicated or in some cases a Measured Mineral resource’.
Mineral reserve, probable – It is the economically mineable part of an Indicated and, in some circumstances, a measured mineral resource demonstrated by at least a preliminary feasibility study. This study is to include adequate information on mining, processing, metallurgical, economic, and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified.
Mineral reserve, proven – It is the economically mineable part of a measured mineral resource demonstrated by at least a preliminary feasibility study. This study is to include adequate information on mining, processing, metallurgical, economic, and other relevant factors that demonstrate, at the time of reporting, that economic extraction is justified.
Mineral resource – A Mineral resource is a concentration or occurrence of solid material of economic interest in or on the earth’s crust in such form, grade (or quality) that there are reasonable prospects for eventual economic extraction. The location, quantity, grade (or quality), continuity and other geological characteristics of a Mineral resource are known, estimated or interpreted from specific geological evidence and knowledge, including sampling. Mineral resources are sub divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories.
Mineral resource, indicated – It is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed.
Mineral resource, measured – It is that part of a mineral resource for which quantity, grade or quality, densities, shape, and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity.
Mineral resource utilization – It is the process of extracting, processing, and consuming naturally occurring minerals from the earth’s crust for different uses, such as in energy production, construction, and manufacturing. It involves the entire lifecycle from finding and mining a mineral deposit to its use in products and the potential for its recycling, with a growing focus on efficiency and sustainability to minimize environmental impact.
Minerals cycle – The minerals cycle starts with the exploration and subsequent primary mineral production, such as excavation, beneficiation, processing and value-addition in a mineral project(s), as well as site decommissioning and remediation. Mineral products reflect the primary entrance of raw materials into the stock available for economic value chains. During the length of stay within value-added chains, the mineral products and compositions can be altered in linear and cyclic processes. Regardless of any sharp definition boundaries, there is an overlapping field with the Specifications for the Application of United Nations Framework Classification (UNFC) to Anthropogenic resources. The Anthropogenic resource specifications provide rules of application of United Nations Framework Classification to sources, including mine tailings, buildings, infrastructure, consumer goods, and from all the material life cycle stages, including production, use and end-of-life. Secondary minerals (including recycled material) can be used to blend primary minerals to optimize the combined value. Exploration methods used to define primary mineral sources can be utilized to classify secondary sources like mine tailings, waste rock dumps and so on. In overlapping project conditions, the choice of which document to prefer is to be based on common sense. A combination of documents can be used as well for describing the different sub-projects.
Mineral silicates – These silicates are a group of rock-forming minerals which are composed mainly of silicon and oxygen, frequently with other metallic elements. They are the most abundant type of mineral in earth’s crust and are essential components of rocks, soils, and many industrial materials. The basic building block of all silicate minerals is the silicon-oxygen tetrahedron, a structure consisting of one silicon atom surrounded by four oxygen atoms in a tetrahedral shape. They are added to the coating for welding electrode to provides slag and give strength to the electrode covering.
Mineral sizers – The basic concept of the mineral sizer is the use of two rotors with large teeth, on small diameter shafts, driven at a low speed by a direct high torque drive system. This design produces three major principles which all interact when breaking materials using sizer technology. The unique principles are the three-stage breaking action, the rotating screen effect, and the deep scroll tooth pattern.
Mineral sources – The term ‘source’ as used in United Nations Framework Classification is equivalent to the term deposit for minerals projects. The Glossary of Geology defines minerals as ‘a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties’. Mineral sources are a potentially economically recoverable accumulation of a specific or a group of minerals.
Minerals reference point – The minerals reference point is a defined physical location within the scope of a mineral project at which a reported estimate is made. The minerals reference point can be the sales, transfer, or use point of a material from the project. It can be an intermediate stage, in which case the reported quantities account for losses prior to but not subsequent to the delivery point.
Minerals specifications – The Minerals specifications provide supplementary specifications for United Nations Framework Classification to classify mineral Projects, including metal ores, technical minerals, evaporates, aggregates and solid energy minerals such as coal and others in alignment with the Sustainable Development Goals (SDGs).
Mineral trapping – It is the process where dissolved carbon di-oxide (CO2) chemically reacts with minerals, typically metal oxides in rocks, to form stable carbonate minerals. This is considered a secure and permanent form of carbon storage, frequently used in carbon capture and storage (CCS) technologies, as it locks carbon di-oxide into a solid, geological form.
Mineral wool – It is a fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics. Applications of mineral wool include thermal insulation (as both structural insulation and pipe insulation), filtration, soundproofing, and hydroponic growth medium.
Miniature boiler – It is a fire pressure vessel which do not exceed these limits, (i) inside diameter of shell – 400 millimeters, (ii) overall length to outside of heads at centre – 1,050 millimeters, (iii) water heating surface – 1.85 square metre, or (iv) 690 kilo pascal (kPa) maximum allowable working pressure.
Miniature circuit breaker (MCB) – It is an automatic, electro-mechanical switch which protects an electrical circuit from damage caused by over-currents or short circuits. It is a reusable safety device which works by detecting abnormal conditions and automatically interrupting the flow of current, preventing damage to appliances and reducing the risk of fire.
Miniature fuel cell – It is a scaled-down fuel cell designed to generate electricity from chemical energy for small-scale, portable, or low-power applications like consumer electronics. Unlike traditional fuel cells, they are compact and can have specific design needs to fit within devices, frequently using low-temperature technologies like PEMFC (proton exchange membrane fuel cell or polymer electrolyte membrane fuel cell) or DMFC (direct methanol fuel cell) which can run on fuels like methanol, which is extracted from a liquid to provide a high energy density.
Miniaturized sensor – It is a sensing device with a very small physical size which can maintain or improve its functional capabilities. These devices are crucial for applications which need unobtrusive monitoring, such as wearable technology and environmental sensors, and their small scale frequently leads to improved sensitivity and lower power consumption. Miniaturization frequently utilizes nano-materials to achieve superior performance because of the to high surface areas and unique electro-chemical, photonic, and magnetic properties.
Mini blast furnace – Mini blast furnace is normally viewed as miniature version of the conventional large blast furnace with the internal volumes ranging from 35 cubic metres to 600 cubic metres.
Mini-grid – It is a localized, independent electricity network which consists of small-scale generators, a distribution network, and storage systems which supply a small group of customers. These systems are engineered to operate separately from the main national grid and are designed to meet local demand, frequently incorporating multiple power sources such as solar, wind, micro-hydro, or fossil fuel generators.
Mini-mills – These mills are normally defined as steel mills which melt scrap metal /direct reduced iron to produce commodity products. Although the mini-mills are subject to the same steel processing requirements after the caster as the integrated steel plants, they differ greatly in regard to their minimum efficient size, labour relations, product markets, and management style.
Minimized spangle – It is a hot dip galvanized coating of very small grain size, which makes the spangle less visible when the part is subsequently painted.
Minimized structure – It is a configuration of a system, like a molecule or a physical component, which has been optimized to achieve the lowest possible energy state or to meet a specific objective. This optimization can involve finding the most stable atomic arrangement in computational chemistry or minimizing material mass, cost, or stress. The process frequently uses numerical algorithms to systematically adjust the structure until the minimum is found.
Minimum batch size – It is the batch size for a break-even point in an economic analysis in which costs are determined as a function of units of output or volume of production. The break-even point occurs at the number of units for which the revenues equal the total costs.
Minimum bend radius – It is the minimum radius over which a metal product can be bent to a given angle without fracture.
Minimum concrete cover – It is the minimum distance from the surface of reinforcement steel to the nearest outer surface of the concrete. This cover protects the steel from corrosion, fire, and other environmental factors, and its needed thickness varies based on factors like exposure conditions and the size of the reinforcement bar.
Minimum conveying air velocity – It is the lowest speed of air needed to successfully transport a material through a pneumatic pipeline without it settling and causing a blockage. This speed is important since if the air velocity drops below this threshold, solids fall out of the gas stream, leading to a blockage, which is a major concern in systems like dilute phase conveying.
Minimum creep rate – It is the creep rate during steady-state (linear) creep behaviour (stage II).
Minimum cutting – It refers to the smallest depth of cut during drilling operations, which is considered to be 0.3 millimeters.
Minimum detectable leakage rate – It is the magnitude of the smallest leakage rate which can be unambiguously detected by a given leak detector in the presence of conditions existing at the time of test. This is normally known as sensitivity.
Minimum detectable signal – It is the smallest signal power which a receiver can reliably distinguish from background noise. It is defined as the minimum input signal level which can be detected and processed to provide a needed output, typically by having a specific signal-to-noise ratio (SNR) above the noise floor. Minimum detectable signal is a measure of receiver sensitivity, meaning a lower minimum detectable signal value indicates a more sensitive receiver.
Minimum efficient scale – It is the optimal level of output for an organization where average cost is minimized, beyond which diminishing marginal returns cause average cost to increase at an increasing rate. It is an important factor in determining the optimal size and equilibrium number of the organizations within an industry.
Minimum energy for ignition – It is the smallest quantity of energy from an electro-static spark which is needed to ignite a flammable gas, vapour, or dust / air mixture. It is a, important safety parameter which indicates how sensitive a substance is to ignition by electro-static discharges. A lower minimum energy for ignition value means the substance is more easily ignited by a spark.
Minimum energy performance – It refers to the established standards which buildings are to meet regarding energy efficiency, measured as energy consumption or calculated energy use per square meter per year, particularly for new constructions and major renovations of large existing buildings. These requirements consider several factors including climatic conditions, thermal characteristics, and energy systems to ensure a holistic approach to energy performance.
Minimum Euclidean distance – It is the smallest straight-line distance between any two distinct points in a set or between any two distinct waveforms in a signal constellation. It is calculated using the standard Euclidean distance formula, which is the square root of the sum of the squared differences of their coordinates, and finds the smallest value among all possible pairs.
Minimum film thickness – It is the smallest separation distance between two moving surfaces in contact, frequently defined as the minimum separation of bearing surfaces separated by a lubricating film. This distance is important for preventing direct metal-to-metal contact, which can cause damage and wear, and is a key parameter in designing bearings and gears for smooth operation and longevity.
Minimum flow area – It normally refers to the smallest cross-sectional area available for a fluid to flow through. In a heat exchanger, it is the smallest flow area in a central baffle space within a tube bundle, calculated based on the dimensions of the tubes and their arrangement, which can include contributions from both the gaps between the tubes and the clearance surrounding the bundle. It is the smallest area between the tubes in a bundle, calculated from the tube and baffle dimensions.
Minimum flow rate – It is the lowest continuous flow through a system which prevents damage by avoiding issues like excessive heat, vibration, and pressure fluctuations. For a pump, it is the minimum flow rate which can be sustained without causing undue wear and tear. In water meters, the minimum flow rate is the lowest rate at which the meter operates accurately.
Minimum fluidization velocity – It is the lowest velocity of a fluid (liquid or gas) needed to suspend a bed of solid particles, making it act like a fluid. At this velocity, the upward drag force from the fluid exactly counteracts the downward force of gravity on the particles, and the pressure drop across the bed equals the weight of the particles minus the buoyant force. This point marks the transition from a fixed bed to a fluidized state.
Minimum grain size – It can refer to either the smallest achievable particle size in a manufactured material or the smallest size found in a naturally occurring material. It is also the smallest particle size in a sintered material, aimed at improving properties. In geology, it is the smallest particle size within a sediment or sedimentary rock, determined through grain size analysis to understand depositional environments.
Minimum heat flux – It is the lowest rate of heat transfer per unit area which is needed to sustain film boiling, which occurs at the Leidenfrost point. At this point, the vapour film surrounding a heated surface becomes unstable, and the heat flux reaches its minimum before transitioning to a more unstable transition boiling regime.
Minimum horizontal stress – It is the smallest magnitude of the two horizontal principal stresses acting on a subterranean formation. It is a critical parameter in subsurface engineering, particularly for determining wellbore stability and the direction and propagation of hydraulic fractures, which grow perpendicular to the least principal stress.
Minimum induced drag – It is the condition where the spanwise distribution of lift is optimized to resemble a semi-ellipse, resulting in a constant downwash along the span, thereby minimizing the drag coefficient. This state occurs when any modification to the elliptic distribution increases the drag.
Minimum input voltage – It is the lowest voltage level needed to power a device, ensuring it operates correctly and performs its intended function. This is important for components like voltage regulators, which need a certain voltage drop across them to function, and other devices like solar charge controllers, which are to be supplied with enough voltage to start up.
Minimum load (Pmin) – In fatigue, it is the least algebraic value of applied load in a cycle.
Minimum miscibility pressure – It is the lowest pressure at which an injected gas and reservoir oil can become completely miscible, meaning they form a single-phase fluid. This pressure is critical for efficient enhanced oil recovery (EOR) since it is the threshold above which the gas can effectively displace the oil by enriching it, leading to higher oil recovery rates.
Minimum potential energy – It is the state of lowest energy for a system, which corresponds to its most stable configuration. This state is achieved when the system is in stable equilibrium, meaning any small displacement from this position results in a net force or torque pushing it back to the minimum energy state. Examples include a ball resting at the bottom of a hill or an object aligned with an external force field.
Minimum power density – It is the lowest level of power intensity which is needed to ensure a signal can be received with adequate strength, protecting receivers from interference. It is used to define the boundary of a broadcast area by calculating where a signal attenuates to this minimum level under specific propagation conditions.
Minimum pressure accumulating conveyor – It is a specialized conveyor which is designed to minimize pressure buildup between adjacent packages or cartons. Regular checks ensure efficient material flow.
Minimum quantity lubrication – It is an eco-friendly lubrication technique which uses a minimal quantity of lubricant, typically mixed with compressed air, to cool and lubricate the cutting zone in machining and other industrial processes. Instead of using large volumes of flood coolant, minimum quantity lubrication applies a fine mist of oil or fluid aerosol to the point of friction, which reduces fluid consumption, waste, and disposal costs while improving tool life and surface finish.
Minimum residual stress (MRS) – This term is applied to products, normally flat rolled, which have been processed to minimize internal stress of the kind that causes distortion when material is dis-proportionately removed from the two surfaces through mechanical or chemical means.
Minimum separation distance – It is the needed minimum space between two objects, such as buildings or facilities, to mitigate risks like fire, explosion, or structural damage, and its specific value depends on the context, like the materials involved, potential hazards, and applicable regulations. It is an important concept in several fields, including construction and explosives handling to ensure safety.
Minimum stress (Smin) – In fatigue, it is the stress which is having the lowest algebraic value in the cycle, tensile stress being considered positive and compressive stress negative.
Minimum stress-intensity factor (Kmin) – In fatigue, it is the minimum value of the stress-intensity factor in a cycle. This value corresponds to the minimum load when the load ratio is higher than 0 and is taken to be zero when the load ratio is 0.
Minimum temperature difference – It is the smallest temperature difference between two fluids in a heat exchanger. This value is crucial for optimizing a heat exchanger’s design, as it directly impacts efficiency, cost, and the amount of heat recovered. A smaller minimum temperature difference can lead to higher heat transfer efficiency and exergy recovery but needs a larger and more expensive heat exchange area.
Minimum ventilation rate – It refers to the prescribed levels of outdoor air supplied to occupied spaces to maintain satisfactory indoor air quality by reducing airborne contaminants.
Minimum wall thickness – It is the smallest possible thickness a component or structure can have while still maintaining its needed functionality, strength, and structural integrity. It is determined by different factors, such as the material, the manufacturing process (like 3D printing or injection moulding), intended use, and external forces like pressure, weight, or stress. In some fields, this minimum is formally specified by codes and standards.
Minimum work input – It is the theoretical least quantity of work needed to perform a process, as defined by the laws of thermodynamics. For a process like compression, this minimum is achieved through an ideal, reversible, and isothermal (constant temperature) process, as it minimizes energy wasted on temperature increases compared to processes like adiabatic compression. Actual work input is always higher than this minimum because of the inefficiencies.
Minimum yield strength – It is the lowest value of stress a material needs to have to withstand without permanent deformation, serving as a guaranteed safety threshold for engineers. It is a specification which a material consistently meets or exceeds to be used for a particular application, ensuring it does not deform permanently under its expected load.
Minimum yield stress – It is the lowest stress at which a material begins to undergo permanent, or plastic deformation. It marks the point where a material’s behaviour transitions from elastic (returning to its original shape) to plastic (permanent change). A lower yield point can occur in some materials, such as steel, where the stress drops after the initial yield before a lower, steady stress value is reached.
Mining – It is the process of extracting valuable minerals or other geological materials from the earth, typically from an ore or vein. It involves digging into the ground to remove substances like coal, metals, and oil, which can then be processed and separated. While traditionally associated with digging, modern mining can occur in open pits or underground.
Mining and quarrying – Mining is the process of extracting minerals from underground or surface deposits, while quarrying is a type of surface mining specifically for materials like stone, sand, and gravel used in construction. Mining is the broader term and can involve underground extraction for minerals, ores, coal, and oil, whereas quarrying focuses on shallow, open-pit extraction for building materials.
Mining engineering – It is the engineering discipline which deals with the extraction of minerals from the ground. It is associated with several other disciplines, such as mineral processing, exploration, excavation, geology, metallurgy, geotechnical engineering and surveying. A mining engineer can manage any phase of mining operations, from exploration and discovery of the mineral resources, through feasibility study, mine design, development of plans, production and operations to mine closure.
Mining equipment – It is the heavy machinery and tools used to extract and process minerals from the earth, including surface and underground operations. This equipment is designed for tasks like drilling, excavation, crushing, and hauling, and includes a wide range of items such as excavators, dump trucks, crushers, and drill rigs.
Mining machinery – It refers to the heavy-duty equipment used for extracting minerals and raw materials from the earth. This machinery is designed to increase productivity and efficiency in operations like excavation, material transportation, and processing, and can include surface mining equipment, underground mining equipment, and mineral processing machines. Examples include excavators, haul trucks, drill rigs, crushers, and continuous miners.
Mining process – The process of mining starts with the discovery of an ore deposit through extraction of iron ore and finally to returning the land to its natural state. It consists of several distinct steps. The first is discovery of the ore deposit which is carried out through prospecting or exploration to find and then define the extent, location, and value of the ore body. This leads to a mathematical resource estimation of the size and grade of the deposit. Exploration and evaluation consist of identification and quantification of ore bodies by using a range of geological, geophysical, and metallurgical techniques. In its simplest forms exploration involves drilling in remote areas to sample areas. The data from exploration activities is logged, mapped, analyzed, and interpreted frequently by using models. After the ore body has been evaluated, a detailed plan for mining is developed. This detailed plan identifies which ore bodies are to be mined and in what sequence in order to deliver the required ore product at an appropriate cost. The process of mine planning is an important step before the start of mine development and it continues on day-to-day basis once the mine becomes operational. To gain access to the ore deposit within an area, it is frequently necessary to mine through or remove waste material (also known as overburden) which is not of an interest. The total movement of ore and waste constitutes the mining process. Frequently, more waste than ore is mined during the life of a mine, depending on the nature and location of the ore deposit. Removal and placement of overburden is a major cost in the mining operation. Mining of the ore can be done either by surface mining, or by underground mining depending on the nature of the deposit. Underground mining includes the use of tunnels or vertical shafts to obtain ore from below earth’s surface. These shafts can penetrate down into the ground or sideways below the earth.
Mining projects – A mining project produces mineral products from a mineral source with defined frame conditions, which provide the basis for environmental-socio-economic evaluation and in decision-making. The project is comprised of a defined activity or set of activities, which provide the basis for estimating technical viability on the one hand (F-axis issues) and environmental-socio-economic viability, on the other (E-axis issues). In United Nations Framework Classification, a project can have quantities in several classes (i.e., reflecting products which are to be sold or used, products which are to be consumed by the project or not used (e.g., fuel and mine tailings) and quantities which are not to be associated with any project (e.g., unrecoverable quantities remaining in situ). In addition, a project can produce multiple products, defined as the quantities crossing the reference points through sub-projects which may or may not have the same categories.
Mining rescue – It is the specialized and coordinated effort to locate and extract trapped or injured miners following an accident, disaster, or other emergency. It involves trained teams using specialized equipment to navigate dangerous conditions, perform first aid, and clear hazards to ensure the survival of those who are trapped.
Mining report – A Mining report is understood as the current documentation of the state of development and exploitation of a deposit during its economic life including current mining plans. It is normally made by the operator of the mine. The study takes into consideration the quantity and quality of the minerals extracted during the reporting time, changes in the Economic Viability categories because of changes in prices and costs, development of relevant technology, newly imposed environmental or other regulations, and data on exploration conducted concurrently with mining. It presents the current status of the deposits, providing a detailed and accurate, up-to-date statement on the reserves and the remaining resources.
Mining shaft – It is a vertical or inclined passage dug from the surface down into the earth to provide access to underground mineral deposits. It serves multiple purposes, including transporting miners and materials, hoisting ore, pumping water, and providing ventilation for the underground mine.
Mining stope – It is a large underground excavation created by the removal of ore. These steplike rooms or chambers provide access to the orebody and are formed through a process called stoping, which involves drilling, blasting, and removing the valuable mineral. Stoping is a key method in underground mining for extracting a mineral deposit.
Mining tailings – These are the waste materials which are left behind after the desired minerals or metals are extracted from ore, typically consisting of crushed rock, water, trace metals, and processing chemicals.
Mining wastes – These are also known as mine-wastes. These are unwanted, currently uneconomic materials, both solid and liquid, generated during the extraction and processing of mineral resources. Mining waste comes from extracting and processing mineral resources. It includes materials such as topsoil overburden (which are removed to gain access to mineral resources), and waste rock and tailings (after the extraction of the valuable mineral).
Mini-plant – It a small-scale, scaled-down version of an industrial production plant used for testing, research, or small-batch production. These plants replicate the full process steps of a larger facility but are more cost-effective and flexible, frequently utilizing modular designs and capable of being located at production sites or research centers. It is designed to replicate its structure and processes in a laboratory setting, incorporating all process steps, connecting and recycle streams, and ensuring proper residence times and insulation.
Mini steel mill – It is a smaller-scale steel manufacturing facility which typically uses scrap metal as its primary raw material. Unlike integrated steel plants which process iron ore, mini mills focus on recycling and refining scrap to produce steel, frequently in the form of long products like reinforcement bars and structural shapes. These mills are characterized by their lower capital investment requirements and smaller operational scale. A typical mini mill has increased its output from 0.5 million tons per annum to 3 million tons per annum.
Minor actinides – These are a group of radioactive elements produced in nuclear reactors, distinct from uranium and plutonium. They are typically defined as neptunium, americium, and curium, though they also include other transuranic elements like berkelium and californium. These elements are significant since they contribute to the long-term hazard of spent nuclear fuel because of their high radioactivity and long half-lives.
Minor alteration – It is a change to an existing product which does not affect considerably its structural strength, weight, balance, and reliability. These alterations are simpler than major alterations and typically use ‘acceptable data’ (like manufacturer recommendations) instead of ‘approved data’ (like regulatory approvals) for installation.
Minor axis – It is the axis of minimum strength or stiffness, frequently called the ‘weak axis’, in a structural member. It is the orientation where a section has a lower capacity to resist bending moments and a higher tendency to deform or buckle. This is in contrast to the major axis, which is the ‘strong axis’ with higher bending resistance. For an ellipse, the minor axis is the shortest diameter perpendicular to the major axis.
Minor axis bending – It is when a structural member bends about its weaker axis, resulting in higher deflection and lower bending capacity compared to major axis bending. This type of bending occurs when the load is applied along the axis with the minimum moment of inertia, and it is an important consideration in structural engineering for safety and efficiency, as the member will be more susceptible to failure under these conditions.
Minor constituent – It is a trace component or element present in a material or system which is not a main ingredient but can influence its overall properties. These minor constituents are found in much smaller quantities than the major components but can still have substantial effects on performance, such as affecting the strength, durability, or chemical behaviour of the final product. Examples include trace elements like potassium oxide (K2O) or sulphur trioxide (SO3) in cement or small quantities of impurities in alloys.
Minor diameter – It is the smallest diameter of a screw thread. It is defined by an imaginary cylinder which touches the root of the thread. For an external thread, this is the diameter at the bottom of the grooves, while for an internal thread, it is the diameter at the top of the internal thread crests. It is also known as the root diameter or core diameter.
Minor hysteresis loop – It is a smaller hysteresis loop which forms within the bounds of the major hysteresis loop when a material is subjected to a driving field which does not reach saturation. It represents the material’s magnetic or thermal response under a cycling field which is below the point of full reversal, and it can reveal detailed information about microscopic reversal mechanisms and material properties which the major loop obscures.
Minor ingredient – It is a component used in small quantities in a mixture or product. The engineering focus is on the specialized systems and equipment needed to accurately measure, handle, and mix these small quantities, frequently under specific conditions like temperature control.
Minor injury – It is the injury other than a fatality or a lost time injury or minor treatment injury (MTI) which is treated by first aid or minor manipulation to provide relief for a strain or bruise. A minor injury does not need treatment by a professionally trained paramedic or physician and does not incur loss of work time other than time of shift on which it occurred. The injured person continues with his normal scheduled work.
Minor Poisson’s ratio – It is the negative ratio of the transverse strain to the longitudinal strain in a unidirectional fibre lamina during transverse loading, and it can be calculated using the relationship between the major Poisson’s ratio and the longitudinal and transverse Young’s moduli.
Minor principal stress – It is the minimum magnitude of normal stress acting on a principal plane, which is an orientation within a material where the shear stress is zero. It represents the lowest normal stress at a given point and is one of two principal stresses in a 2D stress state, the other being the major principal stress, or the highest normal stress.
Minor revision – It typically involves changes which do not affect the part’s form, fit, or function, such as fixing a spelling error, updating documentation, or making minor corrections to a drawing. These revisions are frequently for administrative purposes, do not need a full re-evaluation by reviewers, and maintain backward compatibility with previous versions of the product or document.
Minor treatment injury (MTI) – It is injury other than a fatality or lost time injury, which is treated by a paramedic or a physician without loss of work time other than time of the shift on which it occurred, and the injured person continues with his normal scheduled work.
Minus mesh – It is the portion of a powder sample which passes through a screen of stated size.
Minus sieve – It is the portion of a powder sample which passes through a standard sieve of a specified number.
Minutes of meeting (MoM) – It refers to the official written record of a meeting, documenting key discussions, decisions, resolutions, action items, and attendees, serving as a formal record for reference and accountability.
Mirror-finish grinding – It is a class of grinding processes in which extremely fine abrasive particles are used to achieve reflective surfaces of precise geometry. These methods are used in finishing such items as moulds and dies which are used for making contact lenses and optical components.
Mirror illuminator – It is a thin, half-round opaque mirror interposed in a microscope for directing an intense oblique beam of light to the object. The light incident on the object passes through one half of the aperture of the objective, and the light reflected from the object passes through the other half aperture of the objective.
Mirror region (ceramics, glassy materials) – It is the comparatively smooth region which symmetrically surrounds a fracture origin. The mirror region ends in a microscopically irregular manner at the beginning of the mist region.
Mirror system – It is an arrangement of one or more mirrors used to redirect, focus, or form images of light. These systems use a reflecting surface to guide light, and they are used in a wide range of applications, from simple plane mirrors for a flat image to complex systems with curved mirrors for focusing or steering light, like in telescopes or microscopes.
Misalignment – It is defined as an offset between two mating components. There are several causes of misalignment, but the most common is improper installation. Improper installation can be the result of several things, including incorrect mounting, poor assembly practices, and even damage during shipping.
Misalignment problem – It refers to the condition where the rotational centre-lines of two coupled components, most commonly shafts, are not collinear (do not lie on the same straight line) during operation. This deviation from the ideal position can be static (because of installation errors) or dynamic (because of thermal expansion, load stresses, or foundation settling) and leads to substantial operational issues.
Misalignment safety switch – It is a safety device which is designed to detect and respond to conveyor misalignment. Regular inspections and adjustments are essential for proper functionality and system safety.
Miscellaneous couplings – These couplings get their flexibility from a combination of the mechanisms described above or through a unique mechanism like spring couplings.
Misch-metal – It is a natural mixture of rare-earth elements (atomic numbers 57 through 71) in metallic form. It contains around 50 % cerium, the remainder being principally lanthanum and neodymium.
Miscible displacement – It is the process in which one fluid mixes with and displaces another fluid, exemplified by the leaching of salts from soil when added water interacts with the soil solution.
Miscibility – It is the property of two substances to mix in all proportions (i.e., to fully dissolve in each other at any concentration), forming a homogeneous mixture (a solution). Such substances are said to be miscible (etymologically equivalent to the common term ‘mixable’). The term is most frequently applied to liquids but also applies to solids and gases. An example in liquids is the miscibility of water and ethanol as they mix in all proportions.
Miscibility gap – It is a region in a phase diagram for a mixture of components where the mixture exists as two or more phases i.e., a region of composition of mixtures where the constituents are not completely miscible. The miscibility gap is defined as ‘Area within the coexistence curve of an isobaric phase diagram (temperature vs composition) or an isothermal phase diagram (pressure vs composition)’. A miscibility gap between isostructural phases can be described as the solvus, a term which is also used to describe the boundary on a phase diagram between a miscibility gap and other phases. Thermo-dynamically, miscibility gaps indicate a maximum (e.g., of Gibbs energy) in the composition range.
Misclassification – It is the act of incorrectly assigning someone or something to a wrong group or category.
Misclassification rate – It also known as the error rate. It is a metric used to evaluate the performance of a classification model. It is defined as the proportion of total instances which have been incorrectly predicted by the model.
Misfit – It refers to a difference between the stress-free dimensions or properties of two or more components that are intended to fit together. This mismatch leads to internal stresses and strains within the material or structure.
Misfit dislocation – It is a line defect which occurs at the interface between two materials when their crystal lattices are not perfectly aligned. This lattice mismatch creates stress, which is released by forming these dislocations, which are typically edge dislocations located in the interface plane. They are important in applications like heteroepitaxial growth and metal matrix composites since they can influence material properties, such as strength and electronic performance.
MIS Grangcold process – It is a method of cold-bonded pelletization for iron ore fines, developed by the former Grängesberg company in Sweden. Unlike conventional pelletizing, which uses high-temperature firing, this process achieves pellet hardness through a chemical reaction with a cement-based binder.
Mismatch – It is the misalignment or error in register of a pair of forging dies. It is also applied to the condition of the resulting forging. The acceptable quantity of this displacement is governed by blueprint or specification tolerances. Within tolerances, mismatch is a condition; in excess of tolerance, it is a serious defect. Defective forgings can be salvaged by hot-reforging operations.
Mismatch tolerance – It refers to the maximum allowable difference or deviation between two components or features that are intended to be identical or perfectly aligned. Mismatch tolerance defines how much variation between those two supposedly identical components is acceptable before it affects the overall function or assembly. Mismatch tolerances are crucial for ensuring that parts fit together correctly in an assembly and function as intended. If the deviations are too large, parts might not assemble, fit poorly, or fail to function.
Misplaced core – It is an irregularity of wall thickness, e.g. one wall thicker than the other. It is caused by core out-of- alignment, careless coring-up and closing of mould, or rough handling after the mould is closed.
Misrun – It is a casting not fully formed because of solidification of metal before the mould is filled. It denotes an irregularity on a cast metal surface which is caused by incomplete filling of the mould because of the low pouring temperatures, gas back pressure from inadequate venting of the mould, and inadequate gating.
Missed detection – It is the failure to identify a fault, signal, or object that is actually present. This concept applies to different fields, such as a missed detection rate in fault monitoring, where it is the percentage of faults which have not been detected.
Missing at random – It is said of missing data when the probability of being missing on a variable is unrelated to the value of that variable had it been observed.
Missing data – It is the problem of data being absent for one or more variables in one’s study.
Missing phase – It most commonly refers to single-phasing, where one phase of a three-phase electrical system is lost, causing the system to operate on only two phases. This can damage equipment like motors, which can overheat, draw excessive current, or fail to start. The term can also refer to missing phase data in applications like magnetic resonance imaging, which requires interpolation to reconstruct the full signal.
Mission statement – It is more concrete than vision statement and is specific to the competitive advantage of the organization. It is used to prioritize the organizational activities. There are several benefits of a well-conceived and well-constructed mission statement. Mission statement is not optional. It is crucial that every organization, regardless of size or industry, make a concerted effort to study, develop, codify, and institutionalize a strategic mission statement. Mission is an assumed responsibility of the organization born from its social goals. Mission reflects the way in which vision can be transformed into a tangible existence for the organization. In other words, the organization exists since it creates value for the customers and satisfies their needs. The mission of the organization represents the reason for existence and for creating value for the organization. It synthesizes the existential law of the organization and explains its vision. The mission typically describes what the organization does to achieve its vision.
Mist – It is the suspension of liquid droplets formed when a finely divided liquid is suspended in the air, with a size ranging from 0.01 micrometers to 100 micrometers. Mists are generated in several processes. Mist is considered to be the main aerosol which is generated in the wet processes. Mist remains suspended in the air and has serious consequences on worker health and the environment.
Mistake minimization – It is a process utilized in design to minimize mistakes on system elements for which satisfactory design experience is available. The process involves rigorous application of standards and computerized design methods, reuse of successful designs where possible, and root-cause analysis to eliminate problems from prototypes.
Mist eliminator – It is a device designed to remove liquid droplets or solid particles from a gas stream. These devices, also called demisters or entrainment separators, work by using principles like impingement, diffusion, or centrifugal force to separate the liquid from the gas, which is important for protecting downstream equipment and ensuring process efficiency in different industries.
Mist formation – It refers to the generation of airborne particles from a fluid spray in high-speed machining operations, which can occur through mechanisms such as impaction, centrifugal force, and evaporation/condensation. This phenomenon can lead to health concerns and operational challenges, making it important to utilize fluids designed to minimize mist production.
Mist hackle (ceramics, glassy materials) – It consists of markings on the surface of a crack accelerating close to the effective terminal velocity, observable first as a mist on the surface and, with increasing velocity, revealing a fibrous texture elongated in the direction of cracking and coarsening up to the stage at which the crack bifurcates. Velocity bifurcation or velocity forking is the splitting of a single crack into two mature diverging cracks at or near the effective terminal velocity of approximately half the transverse speed of sound in the material.
Mist lubrication – It is the lubrication by an oil mist produced by injecting oil into a gas stream.
Mitchell bearing – It is a pad bearing in which the pads are free to take up a position at an angle to the opposing surface as per the hydrodynamic pressure distribution over its surface.
Mitigate – It is to lessen or minimize the negative impacts of a potential hazard or risk, such as a disaster, safety issue, or environmental threat. This is done through a proactive and systematic process of identifying potential problems and implementing strategies, such as engineering techniques, improved designs, and safety protocols, to prevent or reduce their severity before they happen.
Mitigation – Mitigation consists of factors or events which can prevent a hazard escalating to an accident, or can reduce the likelihood or severity of an accident. Mitigation can be provided by a number of means including engineered systems, procedures and providence i.e. ‘good luck’.
Mitigation effect – It is the reduction or lessening of a negative impact caused by a hazard or risk through specific actions, such as engineering controls or design changes. This can involve minimizing the consequences of a natural disaster (like making buildings more resistant to wind), reducing the likelihood of a man-made problem (like a system failure), or decreasing the severity of an environmental impact (such as urban heat).
Mitigation measures – These are actions or strategies taken to reduce or minimize the harmful effects of a potential or existing hazard, risk, or negative impact.
Mitigation strategy – It is a plan of action to reduce the severity, likelihood, or impact of a risk or hazardous event. These strategies involve a combination of engineering solutions like building more resilient infrastructure, implementing safety systems, and developing contingency plans to minimize the negative consequences of potential failures, disasters, or other undesirable events.
Mitis process – It is a specialized casting technique for producing malleable iron by adding a small amount of aluminum to wrought iron. The process is named for the resulting malleable cast iron, also known as ‘Mitis iron’. The Mitis casting process technique was developed in the late 19th century and allowed for the casting of low-carbon metal, which is ordinarily difficult to cast.
Mixed air temperature – It is the temperature of the air which results from combining two separate airstreams, typically return air and fresh outside air. It is calculated as a weighted average of the two streams’ temperatures, with the weights based on their flow rates. Understanding this temperature is important for HVAC (heating, ventilation, and air conditioning) system design and performance calculations.
Mixed-anion compound – It is a solid-state material containing a single phase but with two or more different types of anions, such as oxides, fluorides, or nitrides. This combination of different anions can create novel structures and properties which are not seen in single-anion compounds, leading to unique electronic, optical, and magnetic characteristics. Examples include oxy-fluorides and oxy-nitrides.
Mixed ash – It normally refers to a composition of different types of ash, most commonly the combination of fly ash and bottom ash produced from combustion processes. It is a material whose exact composition varies depending on the original fuel and the combustion method used.
Mixed‐bed drying – Mixed bed drying is a process of evaporative drying. The drying of the lignite coal is carried out in circulating fluidized bed where the hot bed material supplies heat for drying. Drying off‐gas is water vapour which is easy to be recovered and utilized. The drying off‐gas is cyclic utilization with heat transfer taking place in drying chamber where lignite coal gets dried.
Mixed-bed ion exchange units – These offer a higher water quality compared to twin bed systems. Mixed-bed ion exchange units hold a mixture of different ion exchange resins housed within a single ion exchange column. When a stream is introduced to the unit, the cation and anion exchange reactions take place simultaneously within the unit, which has the effect of addressing the sodium leakage issues which can compromise the quality of demineralized water produced by a twin-bed ion exchange system. While mixed-bed exchange units produce higher quality water, they also need a more involved resin regeneration process. Additionally, mixed-bed units are more susceptible to resin fouling and / or inferior system function because of the fluctuations in stream contents and are hence typically used downstream of other treatment measures.
Mixed construction – It is a building method which combines factory-made (precast) components with on-site (cast-in-situ) construction. This approach leverages the benefits of both pre-fabrication and traditional building techniques by using components like precast concrete beams and steel girders, while elements like the deck slab or foundations are cast on-site. The goal is to maximize structural and architectural advantages by combining different materials and construction processes.
Mixed convection – It refers to the heat transfer process which involves both forced and free convection, where the effects of the externally imposed flow and the buoyancy-driven flow are of comparable magnitude. This phenomenon occurs particularly when the forced fluid flow velocity is low and / or the temperature difference is large.
Mixed flow fan – It is a hybrid fan which combines characteristics of axial and centrifugal fans. It draws air in axially but the uniquely shaped impeller then directs it outward at an angle between 0-degree and 90-degree. This ‘mixed flow’ allows the fan to produce high airflow, like an axial fan, while also generating high pressure to overcome resistance in ductwork, like a centrifugal fan.
Mixed fluid cascade process – It is a method for liquefying natural gas using three separate mixed refrigerant cycles. These cycles are dedicated to pre-cooling, liquefaction, and sub-cooling, with each cycle using a different mixed refrigerant composition to achieve high energy efficiency. The process is complex and frequently needs optimization to minimize power consumption and maximize efficiency in producing liquefied natural gas (LNG).
Mixed friction – It is the state where both solid and fluid friction occur simultaneously between two surfaces, typically since the fluid lubricant film is not thick enough to completely separate the surfaces. This regime is common in machine elements like gears, seals, and piston rings, and it is characterized by a mix of boundary friction (from solid contact) and fluid friction (from lubricant shear).
Mixed grain size – It means the simultaneous presence of two grain sizes in substantial quantities, with one grain size appreciably larger than the others.
Mixed ionic and electronic conductor – It is a material which simultaneously conducts both ions and electrons (or holes). This dual conduction property allows for the transport of a formally neutral species, making these materials valuable for applications like solid oxide fuel cells, gas separation membranes, and sensors.
Mixed ionic electronic conducting material – It is a material which that conducts both ions and electrons simultaneously. This dual conduction allows for the transport of both charged atomic particles and electrons (or holes) through a single material, making mixed ionic electronic conducting materials valuable for applications like solid oxide fuel cells, batteries, and gas separation membranes.
Mixed liquor – In the activated sludge process, it is the fluid which results by blending settled primary wastewater or equalized influent with a culture of micro-organisms. This mixed liquor is passed through an aeration tank which provides an adequate oxygen rich environment for the microbes to eat and stabilize the organic matter in water.
Mixed liquor suspended solids (MLSS) – Suspended solids level is one of the most important control parameters in biological waste-water treatment processes. It is not only directly related to sludge settling properties and effluent quality, but also related to food / micro-organism ratio which is in turn related with all aspects of sludge properties. Mixed liquor suspended solids represent the total suspended solids including bacteria, dead biomass, and higher life forms, irrespective of biological activity. The organic portion of mixed liquor suspended solids is represented by ‘mixed liquor volatile suspended solids’ (MLVSS) which represents the biomass. Mixed liquor suspended solids is controlled by the sludge wasting rate. Typical mixed liquor suspended solids are dependent on the process type. The more concentrated is the mixed liquor suspended solids, the smaller is the equipment footprint and hence the popularity of membrane bioreactors (MBRs) in space constrained locations. Mixed liquor volatile suspended solids are 0.75 Mixed liquor suspended solids.
Mixed liquor volatile suspended solids (MLVSS) – It refers to the organic and volatile fraction of the suspended solids in the mixed liquor of an activated sludge waste-water treatment system. It mainly represents the micro-organisms and other organic matter which are responsible for consuming pollutants in the waste-water. Essentially, mixed liquor volatile suspended solids indicate the ‘active’ portion of the mixed liquor suspended solids (MLSS), which are the total suspended solids in the mixed liquor.
Mixed lubrication – The film thickness in thick-film lubrication can be reduced by (i) decrease of the viscosity (e.g. owing to temperature rise), (ii) decrease of the sliding speed, or (iii) increase of the load. The surfaces become close to each other and the normal load between the metal working tool and the work piece is supported partly by metal-to-metal contact of the surfaces and partly by the fluid film in hydrodynamic pockets in the surface roughness of the interfaces. This is usually referred to as mixed lubrication and also as the thin film or quasi-hydrodynamic regime. The film thickness is lower than three times of the surface roughness. The coefficient of friction can be as high as about 0.4 (hence, forces and power consumption can increase considerably), and wear can be significant. There is an optimum roughness for effective lubricant entrapment, with a recommended roughness of commonly 15 microns. The hydrodynamic pockets also serve as reservoirs for supplying lubricant to those regions at the interface which are starved for lubricants.
Mixed-matrix membrane – It is a composite material that combines a polymer matrix with dispersed inorganic micro- or nanoparticles, such as metal-organic frameworks (MOFs), zeolites, or covalent organic frameworks (COFs). These membranes aim to synergistically blend the easy processing of polymers with the superior separation performance and enhanced physical properties of porous inorganic fillers, making them promising for applications like gas separation and carbon di-oxide capture.
Mixed-mode bending – It is a standardized test used to characterize the fracture toughness of materials, especially composites, under a combination of mode I (opening) and mode II (in-plane shear) loading conditions. It achieves this by using a specialized fixture which simultaneously applies an opening force and a shear force to a sample with a pre-crack, where the ratio of the two modes can be adjusted by changing the lever arm length. The test is valuable for understanding a material’s resistance to delamination and is the most widely used method for characterizing mixed-mode delamination fracture toughness.
Mixed-mode crack opening – It is the combined opening (mode I) and sliding (mode II or mode III) of a crack, which occurs when a crack is subjected to a combination of normal and shear stresses. This phenomenon is important for understanding the behaviour of structures like bridges and composites, where cracks are not just pulled apart but also pushed or sheared. It involves a combination of opening and sliding displacements at the crack’s faces, influencing how the crack grows and the material fails.
Mixed-mode fracture – It is a type of material failure where a crack grows under a combination of different stress conditions, typically a mix of opening (Mode I), in-plane shear (Mode II), and out-of-plane shear (Mode III). This occurs in real-world situations where materials are subjected to multiple types of loading, such as tension, shear, and torsion, resulting in complex fracture surfaces which display characteristics of both brittle (cleavage) and ductile (dimples) failure.
Mixed oxide (MOX) fuel – It is a blend of oxides of plutonium and natural uranium, reprocessed uranium, or depleted uranium which behaves similarly (though not identically) to the low enriched uranium feed for which many nuclear reactors are designed. Mixed oxide fuel is an alternative to low enriched uranium fuel used in the light water reactors which predominate nuclear power generation.
Mixed plastic granule – It is a versatile recycled material produced from a blend of different post-consumer and post-industrial plastic wastes. These small pellets are typically about the size of a grain of rice and are reprocessed to create a uniform raw material suitable for manufacturing.
Mixed potential – It is the potential of a sample (or samples in a galvanic couple) when two or more electro-chemical reactions are occurring. It is also called galvanic couple potential.
Mixed potential theory – It is a hypothesis which describes electro-chemical processes as combinations of partial reduction and oxidation reactions, with the overall corrosion process being influenced by polarization at active anodic and cathodic sites. This theory helps predict the corrosion behaviour of materials in different corrosive environments.
Mixed resin – It is a combination of different resin components which have been thoroughly mixed for use in applications like composites. It can also refer to a mix of cation and anion exchange resins used together to purify water, frequently called a ‘mixed bed resin’.
Mixed salt – It is a salt compound containing more than one cation or anion, which are combined in a fixed proportion. For example, sodium potassium carbonate (Na2K2CO3) is a mixed salt since it contains both sodium (Na+) and potassium (K+) cations alongside the carbonate anion [(CO2)-3]. When dissolved in water, a mixed salt dissociates into all of its constituent ions.
Mixed salt solution – It is a solution containing multiple salts, such as the water-lithium bromide-calcium bromide (H2O-LiBr-CaBr2) and water-lithium chloride-calcium chloride (H2O-LiCl-CaCl2) systems, where the boiling point and enthalpy can be influenced by the molar fractions of the salts present.
Mixed-signal integrated circuit – It is a type of integrated circuit which combines both analogue and digital circuitry, facilitating the processing of both analogue signals and digital logic. Examples include analog-to-digital converters (ADC), digital-to-analog converters (DAC), and phase-locked loops (PLL).
Mixed soil – It refers to soil which has been combined with other materials to change its properties, either by physically blending it with binders like cement for soil improvement, or by creating a custom blend for different purposes. The term can also describe a raw material for manufacturing, made by mixing soil with other ingredients like minerals and chemicals.
Mixed storage – It is the practice of storing multiple different materials or different batches of the same material in a single storage bin or unit. This is a common configuration in warehousing and logistics which allows for the efficient use of space, especially when dealing with small quantities of different items.
Mixed variable – Some variables are between being categorical and numerical. For example, daily rainfall is exactly zero on all dry days, but is a continuous variable on rainy days. Wind speed is similar, with zero being calm. Frequently there is a single ‘special value’, here zero, and otherwise the variable is continuous. This is not always the case. For example, sunshine hours expressed as a fraction of the day length, is zero on cloudy days and 1 (or 100 %) on days with no cloud (or haze). In the analysis it is normal to treat the categorical and the numerical parts separately. However, categorical variables are normally summarized using frequencies and percentages.
Mixed Weibull distribution – It is a variation of the Weibull distribution used to model data with distinct sub-populations which can represent different failure characteristics over the lifetime of a product. Each sub-population has separate Weibull parameters calculated, and the results are combined in a mixed Weibull distribution to represent all of the sub-populations in one function.
Mixer – It is a circuit which combines two input signals to produce new output signals, either by adding them together in a linear mixer or by multiplying them in a non-linear mixer. The outputs typically include the original frequencies and their sum or difference, which can be processed further using filters.
Mixer, hot metal – It is a large tilting type holding furnace for hot metal. It keeps the hot metal molten until it is needed for transfer to a steelmaking furnace. The bottom and walls of the hot metal mixer are made of magnesite refractories and the roof of silica refractories.
Mixing chamber – It is that part of a welding or cutting torch in which a fuel gas and oxygen are mixed. It is also a device or space where two or more fluid streams combine to create a single, uniform mixture. These chambers are critical in different processes, such as in pumps, compressors, and chemical reactors, to ensure efficient blending of materials.
Mixing height – It is also known as mixing depth. It refers to the height above the surface to which pollutants or other constituents emitted or entrained into the lower atmosphere can be vertically dispersed by turbulence and convection.
Mixing law – It is a mathematical formula used to predict the properties of a mixture by combining the properties and volume fractions of its individual components. These laws are applied across different fields to estimate a mixture’s effective properties like dielectric constant, thermal conductivity, and density, and are used in several fields. They provide a way to calculate the properties of a composite material or a multi-component system based on the characteristics of its parts.
Mixing layer – It is a turbulent, well-mixed region at the surface of a fluid, such as the atmosphere or ocean, where properties like temperature, salinity, and moisture are relatively uniform because of the mixing from forces like wind, waves, or convection. In the atmosphere, it is the layer extending up to the mixing height, while in the ocean, it is the upper layer influenced by surface turbulence and exchange with the atmosphere.
Mixing, mix – In powder metallurgy, it is the thorough intermingling of powders of two or more different materials. It is not to be confused with blending.
Mixing power – It is the energy needed per unit time to overcome a fluid’s resistance to stirring in a mixing process. It is determined by factors like stirrer speed, impeller geometry, fluid viscosity and density, and the size and shape of the vessel. This power is calculated using equations that relate these variables, frequently expressed using dimensionless numbers like the power number (Np).
Mixing region – It is an area where fluids or substances blend together through processes like advection and turbulence. In a mixing region, initial inhomogeneities are reduced as the components are mixed, leading to a more uniform blend. Examples include a turbulent atmospheric layer where pollutants disperse, an area of the ocean where wastewater dilutes, or the blending zone in a chemical reactor.
Mixing rule – It is a mathematical equation used to estimate the properties of a mixture by combining the properties of its individual components. These rules are used in different fields to calculate properties like viscosity, density, and the parameters for thermodynamic models. In thermodynamics, mixing rules are used to calculate average values for a mixture’s attractive and repulsive forces from the individual components’ parameters, frequently using binary interaction parameters to account for specific molecular interactions.
Mixing temperature – It is the temperature at which different substances are combined, and it can refer to the specific temperature needed for a successful mix, the final temperature after mixing, or the temperature of a mixture of fluids. It is important for product quality, chemical processes, and physical phenomena like emulsification or atmospheric air blending.
Mixing tool – It is a device or implement used to combine two or more substances into a uniform mixture, with specific types used for different applications. Examples are large machinery for industrial processes like concrete or chemical mixing.
Mixing valve – It is a device which combines and controls the flow of two or more fluids, such as hot and cold water, to produce a desired output temperature or concentration. It is normally used in industrial settings to maintain consistent temperatures for processes. The valve regulates the proportion of each incoming fluid stream to maintain a consistent output temperature, even if the inlet temperature or pressure fluctuates.
Mixing zone – Water-quality-based effluent limits allow, where necessary, limited zones for the initial dilution of effluent where in-stream objectives can be exceeded, called mixing zones. These are areas which are small enough so as not to interfere with other water uses. They are established to limit the acute lethality of organisms passing through the effluent plume and ensure the protection of the water body as a whole from chronic toxicity. Mixing zone is also known as effluent plume.
Mixture – It is a material made up of two or more different substances which are mixed physically but are not combined chemically (i.e. a chemical reaction has not taken place which has changed the molecules of the substances into new substances). A mixture has two or more components which are thoroughly intermingled by mixing.
Mixture composition – It is the proportion of different components within a sample of a mixture, and it is variable rather than fixed. This can be expressed in different ways, such as mass percent, volume percent, or mole percent, and is determined by the specific arrangement and quantity of the substances which are physically, but not chemically, combined.
Mixture constituent – It is a single, individual substance within a mixture, such as oxygen or nitrogen in the air, or salt and water in saltwater. These individual substances are physically combined but are not chemically bonded, which means they keep their original properties and can be separated using physical means.
Mixture of ideal gases – It is a combination of multiple ideal gases which behave independently, with no intermolecular forces between them. Each gas component acts as if it occupies the entire volume alone, and the total pressure of the mixture is the sum of the partial pressures of each component, as described by Dalton’s law of partial pressures.
Mixture preparation – It is the process of combining two or more substances without a chemical reaction, so each substance retains its individual chemical identity. The process can be mechanical blending or the intentional creation of a solution, where the components are not in a fixed ratio and can be separated by physical means
MKS system – It is a measurement system which uses the meter (m), kilogram (kg), and second (s) as its base units for length, mass, and time, respectively. It is a metric system which forms the foundation for the modern International System of Units (SI). Other units like the newton (force), joule (work), and watt (power) are also part of this system.
Mnemonic device – It is a memory aid which uses patterns like phrases, acronyms, or rhymes to help people remember complex information more easily. It works by creating associations between new information and something simpler, making it easier to encode and retrieve, and can be used for several subjects.
Mobile cations – These are defined as positively charged ions which can migrate towards the cathode in an electric field, facilitating the deposition of metallic form at the electrode during mass transport processes.
Mobile communication – It refers to the communication of mobile phone users through a cellular network of base transceiver stations, enabling functions like calling and texting within varying coverage ranges. It encompasses the use of smartphones for internet-based services and facilitates several location-based services and information dissemination.
Mobile crane – Mobile crane is mounted on a carrier normally a truck which provides the mobility for the crane. This crane has two parts namely (i) a carrier which is frequently referred to as the ‘lower’ and (ii) a lifting component which includes the boom also referred to as the ‘upper’. These are mated together through a turntable which allows the upper to swing from side to side. The present-day hydraulic truck cranes are normally single engine machines, with the same engine powering the under-carriage and the crane. The upper is normally powered through hydraulics run through the turntable from the pump mounted on the lower. Earlier the hydraulic truck cranes had two engines. One in the lower is used for the crane to travel on the road and ran a hydraulic pump for the outriggers and jacks. The second in the upper ran the upper through a hydraulic pump of its own.
Mobile dislocations – It refer to dislocations within a material which can move and contribute to deformation. Their density evolves based on the rates of generation and annihilation, influenced by the material’s microstructural conditions and external strain rates.
Mobile equipments – They normally refer to vehicles or machinery which are capable of being driven or drawn on a highway. They refer to equipment such as earthmovers, tractors, diggers, farm machinery, and forklifts etc., which even when self-propelled, are not considered automobiles.
Mobile ions – These are charged atoms or molecules which are free to move within a substance, such as a liquid solution or a solid, and can conduct electricity. In liquids like saltwater or molten salts, they move freely, allowing the solution to act as an electrolyte. In solid-state materials, mobile ions can migrate under an electric field, affecting the material’s performance in devices like solar cells.
Mobile phase – In chromatography, it is the gas or liquid which flows through the chromatographic column. It is a sample compound in the mobile phase which moves through the column and is separated from compounds residing in the stationary phase.
Mobile phase composition – It is the specific mixture of solvents and additives used in chromatography, such as high-performance liquid chromatography (HPLC) or thin-layer chromatography (TLC), to separate analytes. The composition can be held constant or can be programmed to change over time. It is critical since it affects the separation of compounds by influencing their interaction with the stationary phase and the overall efficiency of the separation process.
Mobile source – In the context of air pollution, a mobile source refers to any vehicle, engine, or equipment which moves or can be moved from one location to another, generating air pollution as it operates.
Mobile phone – It is a handset which connects to the public switched telephone network by radio.
Mock up drill – It is a simulated emergency exercise conducted to test the effectiveness of emergency response procedures, evaluate the preparedness of personnel, and identify weaknesses in the emergency plan for a specific facility or project.
Modal analysis – It is an engineering technique which studies a structure’s natural vibration properties namely its natural frequencies, damping, and mode shapes. By understanding these inherent characteristics, engineers can predict and analyze a structure’s dynamic behaviour under external forces, helping them design safer, more efficient, and quieter products. This analysis can be done through simulation (theoretical modal analysis) or physical testing (experimental modal analysis).
Modal dispersion – It is the spreading of a light pulse in a multimode waveguide (like an optical fibre) because of different light paths, or modes, traveling at different speeds. This causes the modes to arrive at the receiver at different times, degrading the signal by making it impossible to distinguish between pulses, especially at higher data rates.
Modal interval – It is also called modal class. It refers to the class interval in a grouped frequency distribution which contains the highest frequency or the most data points.
Modbus – It is a brand name for a serial protocol for industrial control equipment communication.
Mode – It is one of the three classes of crack (surface) displacements adjacent to the crack tip. These displacement modes are associated with stress and strain fields around the crack tip and are designated ‘I’ (opening mode), ‘II’ (in-plane shear), and ‘III’ (out-of-plane shear, torsion). In reliability-centered maintenance, mode is the total collection of a set of events that are likely to cause a failed state. In statistics, it is the most commonly occurring value in a distribution. It is the most common or most probable value observed in a set of observations or sample. In statistics, mode is a way of expressing, in a (normally) single number, important information about a random variable or a population. the mode is the value that appears very frequently in a set of data values. If ‘X; is a discrete random variable, the mode is the value ‘x’ at which the probability mass function takes its maximum value. In other words, it is the value that is most likely to be sampled.
Mode ‘I’ fracture – It refers to the cracking of a material, which occurs when the maximum stress at the crack tip reaches the theoretical strength of the material, accompanied by a reduction in system energy.
Mode analysis – It is the process of identifying the natural vibration properties of a structure, including its natural frequencies, mode shapes, and damping. This can be done computationally (like through ‘finite element analysis’) or experimentally, and the results are used to understand how a structure vibrates and deforms under different forces. Essentially, mode analysis breaks down a complex vibration into a combination of these simpler, natural vibration states, which are called its ‘modes’.
Mode delamination – It refers to the separation of layers in composite materials, which can occur due to weak interfacial adhesion between the fibre and matrix, and is categorized into modes I, II, and III based on the type of mechanical loading involved, such as opening, sliding shear, and tearing shear.
Mode energy – It can be defined as the energy associated with a specific state or configuration of a system, such as the electronic mode in materials, which can be analyzed through models like the simplex model to calculate internal energy at high temperatures.
Mode fracture criterion – It refers to a method used to analyze the mixed-mode crack opening in adhesive bonds, which involves comparing the sum of strain energy release rate (SERR) components to a critical strain energy release rate value. It can include several formulations, such as the power-law criterion, to account for different modes of crack propagation.
Mode interference – It is a type of interference which disrupts a signal by introducing unwanted signals or modifying the intended signal, frequently occurring in communication systems.
Model-based analysis – It involves using mathematical or digital models to analyze, predict, and understand a system’s behaviour throughout its lifecycle, frequently replacing traditional document-based workflows with a single, authoritative digital source of truth. It encompasses methods like ‘model-based systems engineering’ (MBSE), where digital models represent requirements, architecture, and interfaces, and ‘model-based definition’ (MBD), which embeds all product information directly into 3D CAD (computer aided design) models.
Model-based control – It is an engineering discipline where a control system uses a mathematical model of the physical system for its controlling to predict behavior and optimize performance. This approach, also known as ‘model-based design’ (MBD) or model-based systems engineering’ (MBSE), uses models for analysis, simulation, and verification, which can improve system design, performance, and safety, and it allows for complex systems to be developed more efficiently by enabling validation before hardware implementation.
Model-based definition – It is an approach to product development which uses a single, intelligent 3D model as the single source of truth for all product and manufacturing information (PMI). This eliminates the need for separate 2D drawings by embedding all necessary data, such as dimensions, tolerances, and materials, directly into the 3D model. Model-based definition improves accuracy, communication, and collaboration across teams, and enables automation in manufacturing.
Model-based systems engineering – It is a methodology which uses digital models as the main tool for designing, analyzing, and managing complex systems, replacing traditional document-centric approaches. It involves creating a single, coordinated source of data which represents system needs, architecture, and behaviour, which helps engineers improve collaboration, reduce errors, and manage complexity across the entire system lifecycle.
Model building – It is the process of creating a representation of a real-world system or product. This can involve building physical scale models for visual and testing purposes, or creating digital models using software like CAD (computer aided design) for analysis, simulation, and design refinement. It also refers to developing machine learning models to identify patterns in data for predictive insights.
Model calibration – It is the process of adjusting a model’s parameters to make its outputs align with experimental measurements or real-world data. This is an iterative process of comparing the model’s predictions to observed data, and then modifying the input parameters to minimize the difference between the model and reality. The goal is to improve the model’s accuracy, reliability, and the trustworthiness of its predictions.
Model, engineering – Model comes after the drawings. It is made for the project and it personify how the project is going to look when it is complete. The benefit of making model is that it helps the engineers in identifying the difficulties. Everything is clear in a model, the design, elevation, as well as internal and external detailing. The engineering model is represented by a collection of predefined parameterized engineering drawings of mechanical parts, while the graph model is derived from the engineering model with different level of detailsIn automation, model serves as a blueprint for the automated process, defining the sequence of activities, the conditions under which they occur, and the resources required.
Model-free control – It is a control approach which utilizes continuously updated local modeling based on the input-output behaviour of a system, accounting for unknown, potentially non-linear and time-varying aspects without needing a formal modelling procedure.
Modelling – It is the creation of a simplified representation of something in a different field like science, engineering, or data analysis. Tit is a process of building a model to study, simulate, or predict an outcome. It consists of the use of computers to simulate a physical system. Computers perform the numerical analysis and frequently graphically display the results.
Modelling and simulation – It is the use of models (e.g., physical, mathematical, behavioural, or logical representation of a system, entity, phenomenon, or process) as a basis for simulations to develop data utilized for managerial or technical decision making. In the computer application of modelling and simulation a computer is used to build a mathematical model which contains key parameters of the physical model. The mathematical model represents the physical model in virtual form, and conditions are applied that set up the experiment of interest. The simulation starts, i.e., the computer calculates the results of those conditions on the mathematical model, and outputs results in a format which is either machine-readable or human-readable, depending upon the implementation.
Modelling concept – It is the abstract representation of a system, process, or idea, used to analyze, design, and understand it. This involves creating a simplified facsimile (a physical, mathematical, or logical replica_ which can be used for different purposes, such as testing, simulation, and data analysis, ultimately reducing costs and improving efficiency.
Modelling error – It is the difference between the actual physical system and its mathematical, physical, or logical representation. These errors can arise from two main sources namely conceptual errors, which stem from inaccurate assumptions or simplifications in the model’s design, and instance errors, which result from numerical approximations (like discretization in finite element analysis) and implementation details.
Modelling work – It is the process of creating simplified representations of systems, products, or processes to understand, analyze, and predict their behaviour. This can involve physical models, mathematical equations, or computer-based simulations, and the models are used for tasks like design optimization, problem identification, and project management.
Model, mathematical – It is a mathematical description of the physical behaviour underlying a manufacturing process which is used to predict performance of the process in terms of operating parameters. Very frequently process models are reduced to software and are manipulated with computers.
Model parameter – It refers to the crucial process of identifying, selecting, and specifying the quantifiable values or variables which define a system’s behaviour within a particular theoretical or computational model. These parameters are necessary for accurately simulating, analyzing, and predicting the performance of an engineered system, structure, or process.
Model predictions – These refer to the outputs generated by a model which aim to provide insights based on the underlying data. They are to be sufficiently precise, and their accuracy can be assessed using methods such as confidence intervals and the prediction profile likelihood, which propagates uncertainty from experimental data to the predictions.
Model predictive control (MPC) – It is a control strategy which uses a mathematical model of a system to predict its future behaviour and optimize control actions over a defined time horizon. It is an advanced control method widely used in industrial processes and systems, particularly where constraints and multiple inputs / outputs are involved.
Model, process – It is a graphical or mathematical representation of a process. It includes all the steps, activities, or tasks involved in the process, the sequence in which they occur, and the relationships between them.
Model scale – It is the ratio of the linear dimensions of a physical or digital model to the actual dimensions of the real object (prototype) it represents. This ratio, frequently expressed as a fraction or a ratio (e.g., 1:100 or 1/100), ensures that the model is geometrically proportional to the prototype.
Model, statistical – In statistical analysis, the word ‘model’ is used in several ways and means different things, depending on the discipline. Statistical models form the bedrock of data analysis. A statistical model is a simple description of a process which can have given rise to observed data. A model is a formal expression of a theory or causal or associative relationship between variables, which is regarded by the analyst as having generated the observed data. A statistical model is always a simplified expression of a more complex process, and hence, the analyst is to anticipate some degree of approximation a priori. A statistical model which can explain the greatest amount of underlying complexity with the simplest model form is preferred to a more complex model. There are several probability distributions which are key parts of models in statistics, including the normal distribution and the binomial distribution.
Model structure – It is the organization of components in a model, which can be physical, mathematical, or computational. A structural model is a specific type of model used to represent the static features of a system, focusing on its components, relationships, and overall design. Key engineering examples include physical scale models for testing, mathematical models of loads and components, and software diagrams that depict the system’s components and their connections.
Model study – It is a systematic approach which uses a physical, mathematical, or logical representation (a model) of a system, entity, or process to understand its behaviour, explore design alternatives, predict performance, and validate assumptions before creating the actual, frequently larger or more complex, real-world artifact or system.
Model updating – It is an iterative process of adjusting the parameters of a numerical model (like a finite element model) to better match its predictions to experimental results from a real structure. This process aims to improve the model’s accuracy and reliability by reducing the discrepancy between its simulated behaviour and the actual behaviour of the physical object. It is frequently used for damage detection and for creating more validated models for future analysis.
Modem – It means modulator-demodulator which is an interface between a computer system and a telephone network.
Mode of operation – It is a specific way a system, device, or process functions or operates under certain conditions, defining its configuration, performance parameters, and behaviour.
Moderate climate – It has mild temperatures which are neither too hot nor too cold, with moderate rainfall and small seasonal changes. It is characterized by comfortable, non-extreme weather conditions, frequently with mild summers and cool winters.
Moderate impact – It is a level of harm which is not minor but not severe, causing a substantial adverse effect which can involve degradation of services, damage to assets, financial loss, or non-life-threatening injury to individuals. The impact is noticeable and can interfere with fundamental functions, but it can frequently be mitigated or corrected with proper management or corrective actions.
Moderate temperature – It is one which is neither too hot nor too cold, falling in a comfortable and balanced range. This typically refers to temperatures which are pleasant for most people, frequently considered to be around 20 deg C to 25 deg C for general comfort, though this can vary by individual and local climate norms.
Moderator – It is a substance which slows neutrons down in a ‘thermalʼ reactor to enable fission to take place. The term ‘thermal’ refers to the energy of the neutrons after moderation (slowing).
Modern composite material – It is an engineered material made from two or more constituent materials with considerably different physical or chemical properties. These materials are combined on a macroscopic scale to create a new material which is superior to its individual components, frequently possessing higher strength, stiffness, or other properties tailored for specific applications. Examples include fibre-glass and carbon-fibre reinforced polymers, which combine reinforcing fibres with a matrix material like resin.
Modern control theory – It is a framework for analyzing and designing complex systems using state-space representation and advanced mathematical techniques. It uses first-order differential equations to model systems based on their state variables, which are the minimum set of variables needed to predict the system’s future behaviour. This time-domain approach differs from classical control theory, which frequently relies on frequency-domain analysis and is limited to single-input / single-output systems.
Modern manufacturing – It is the use of advanced technologies, strategic planning, and efficient organizational structures to produce goods from raw materials. It involves applying physical, chemical, and digital processes to transform materials into more valuable products, frequently through mass production or highly customized and versatile methods. Key characteristics include complex machinery, a focus on quality and efficiency, and the integration of automation and data-driven systems.
Modes – It is the three classes of crack (surface) displacements adjacent to the crack tip. These displacement modes are associated with stress-strain fields around the crack tip and are designated class I, class II, and class III and represent opening, sliding, and tearing displacements respectively.
Modes of variation – It refer to the distinct patterns or directions of variability in a dataset, frequently identified through statistical methods like ‘principal component analysis’ (PCA). These modes, which are like principal axes of variation, are ordered by how much of the total variance they represent, with the first mode capturing the most variation. They provide a way to describe the main ways a set of data points are spread out or how a shape can change.
Mode stability – It refers to the condition under which laser oscillation can maintain a steady-state output without transitioning to unstable multimode states, typically determined by the relationship between external feedback and cavity parameters. Unstable modes arise when certain reflectance thresholds are exceeded, leading to a potential shift from single-mode to multimode output.
Mode solution – It refers to a uniform stationary solution characterized by specific values of modal amplitudes, which satisfy corresponding equations derived from system parameters, and can include trivial and nontrivial stationary states in the context of laser systems.
Modification – It is the treatment of molten hypoeutectic (8 % to 13 % silicon) or hypereutectic (13 % to 19 % silicon) aluminum-silicon alloys for improving the mechanical properties of the solid alloy by refinement of the size and distribution of the silicon phase. It involves additions of small percentages of sodium, strontium, or calcium (hypoeutectic alloys) or of phosphorus (hypereutectic alloys).
Modified ASTM acetic acid salt intermittent spray (MASTMAASIS) test – It is used to predict the alloy system’s exfoliation corrosion (EFC) susceptibility.
Modified binder – It is a base binder, typically asphalt, which has been altered with additives like polymers or other agents to improve its performance characteristics, such as resistance to high-temperature rutting, fatigue, and low-temperature cracking. This modification improves the binder’s physical and chemical structure, making it more durable and resilient, especially under extreme temperature variations and heavy traffic loads.
Modified bitumen – It is the bitumen which has been improved by adding 2 % to 8 % of polymers, which can be plastic or rubber, to improve its strength and rheological properties. This modification results in increased elastic response, cohesive properties, fracture strength, and ductility.
Modified cam-clay model – It is an elastoplastic constitutive model used in geotechnical engineering to simulate the stress-deformation behaviour of soils like clay. Alternatively, it can refer to a modified cam mechanism in mechanical engineering, where the shape of the cam is altered from its basic form to achieve a specific, non-standard follower motion, as seen in some internal combustion engines and automated machinery.
Modified concrete – It is a type of concrete which has had substances like polymers, chemicals, or other admixtures added to the standard mixture of cement, water, and aggregate. This addition alters and typically improves the concrete’s properties, making it stronger, more durable, and more resistant to water, abrasion, and chemicals.
Modified Lottman test – It is a method for assessing moisture damage resistance in asphalt mixtures, defined by comparing the tensile strength of water-conditioned samples to that of unconditioned samples. It works by calculating the ‘tensile strength ratio’ (TSR), which involves subjecting one set of samples to partial saturation and freeze-thaw cycles and another to just freeze-thaw cycles, then measuring the indirect tensile strength of both. A tensile strength ratio higher than 0.8 indicates that the material is resistant to moisture damage.
Modified parabolic flow characteristic – It is an inherent flow characteristic which provides equal percentage characteristic at low closure member travel and around a linear characteristic for upper portions of closure member travel.
Modified Proctor test – It is a laboratory procedure used to determine the optimum moisture content (OMC) at which soil achieves its maximum dry density (MDD) through a higher level of compaction than the standard test. This is achieved by using a heavier rammer and more blows per layer, which is particularly important for projects needing heavier compaction. The test produces a compaction curve, which plots dry density against moisture content, allowing engineers to understand the soil’s properties for construction purposes.
Modified Reynolds equation – It is a mathematical formulation which alters the standard Reynolds equation to account for factors not included in the original, such as surface roughness, pressure-dependent viscosity, or non-Newtonian fluid properties. It is used in lubrication analysis and other fluid dynamics applications to more accurately predict fluid behaviour under complex conditions, leading to improved performance in engineering designs.
Modified Reynolds’ number – It is a variation of the standard Reynolds’ number used for specific fluid flow applications, such as non-Newtonian fluids or two-phase flows. It accounts for the fluid’s properties, like a power-law fluid’s apparent viscosity or the average viscosity in a two-phase mixture, which are not handled by the original formula. This modification allows for more accurate characterization of the flow regime (laminar vs. turbulent) in these complex scenarios.
Modified sample – It is an original sample which has been altered or changed to change its properties, concentrate an analyte, or serve a new purpose, as per the context. Examples include a material altered through etching or thermal oxidation to change its properties, a sample concentrated to prepare it for laboratory analysis, or a sampling scheme changed to incorporate quality history. The specific definition depends on the field, such as chemistry, engineering, or statistics.
Modifying factors – These are considerations used to convert Mineral resources to Ore reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors.
Modular belt structure – It is a conveyor belt composed of individual interlocking modules. Periodic checks are necessary to assess module integrity, alignment, and overall belt condition.
Modular bridge – It is a bridge built from pre-fabricated sections or ‘modules’ which are constructed off-site and then assembled at the job site for rapid installation. This method, also known as ‘accelerated bridge construction’ (ABC), uses components like beams, decks, and support structures to create a finished bridge, frequently in a shorter timeframe and with less disruption than traditional methods.
Modular building – It is a prefabricated building which consists of repeated sections called modules. Modularity involves constructing sections away from the building site, then delivering them to the intended site. Installation of the prefabricated sections is completed on site.
Modular concept – It is a design approach where a system is divided into smaller, self-contained units or ‘modules’ which can be independently created, modified, and exchanged. These modules interact with each other through standardized interfaces, allowing for a system to be flexible, scalable, and easier to customize or maintain compared to a single, tightly integrated system.
Modular construction – It is a process in which a building is constructed off-site, under controlled plant conditions, using the same materials and designing to the same codes and standards as conventionally built facilities, but in about half the time. Buildings are produced in ‘modules’ which when put together on site, reflect the identical design intent and specifications of the most sophisticated site-built facility without compromise.
Modular helium reactor – It is an advanced, high-efficiency nuclear reactor which uses helium gas as a coolant, graphite as a moderator, and TRISO (TRi-structural ISOtropic) fuel particles. These reactors are designed with passive safety features and a modular, standardized design, allowing them to be potentially more cost-effective to manufacture. While frequently used for electricity generation with a gas turbine, they can also provide high-temperature heat for industrial processes.
Modular multilevel converter – It is a type of power converter topology which uses a series of identical, individually controllable submodules to generate a high-quality, stepped alternating current or direct current voltage. These converters are modular and scalable, making them suitable for high-voltage applications like HVDC (high voltage direct current) transmission, renewable energy integration, and large motor drives. Key advantages include modularity, scalability, fault tolerance (a faulty submodule can be bypassed), and a reduction in the need for large output filters.
Modular organization – It is a structure where organizational operations are divided into separate, semi-autonomous units or modules. These modules can operate independently but are coordinated and integrated to achieve the organization’s overarching goals. This structure allows the organization to outsource specific functions or processes to external providers, focusing on core competencies while maintaining flexibility and efficiency.
Modular ratio – It is the ratio of the Young’s modulus of elasticity of two different materials, normally used in composite structures like reinforced concrete. It is expressed as m = Es/Ec, where ‘Es’ is the modulus of elasticity of steel and ‘Ec’ is the modulus of elasticity of concrete. This ratio is used to convert the area of one material to an equivalent area of another for stress and strain calculations, allowing engineers to analyze composite sections as if they are made of a single, homogeneous material.
Modular reactor – It is a type of nuclear reactor which is smaller than a conventional one and is built in modules at a factory before being transported to a site for assembly and installation. These ‘small modular reactors’ (SMRs) typically have a power output of up to 300 MW per module and are designed for faster deployment, reduced construction time, and lower costs through standardized, factory-based production.
Modulated differential scanning calorimetry – It is a thermal analysis technique which adds a small oscillation to the normal linear heating rate of a sample. This modulation separates thermal events into a ‘reversing’ (heat capacity-related) and a ‘non-reversing’ (kinetic) component, providing more detailed information than conventional differential scanning calorimetry by separating complex or overlapping transitions and allowing for the direct measurement of heat capacity.
Modular structure automation – Modular structure automation brings an agility and flexibility to production never before seen. It brings a completely new way of thinking by subdividing process line tasks into smaller, more manageable building blocks. By acting like building blocks, the modules can be replicated and used to number up or number down in order meet rapidly changing capacity demands. By simply changing a few modules, a completely new product can be produced. Highly developed standard solutions make it easy to implement logic and communication to external systems.
Modulation – It is the impression of information on a carrier wave for transmission.
Modulating – It is a term which is used for describing the method of controlling flow through a valve by varying the pressure drop across it.
Modulating burners – In these burners, the delivered output is automatically varied continuously between a minimum and maximum value, for optimum delivery of the thermal output in relation to system requirements.
Modulating control – It is a method of regulating a system by continuously adjusting a variable to maintain a desired setpoint, unlike simple on/off control. It uses a modulating control valve or a similar device which can operate at any intermediate position between fully open and fully closed, allowing for precise adjustments of flow, temperature, or pressure. This is achieved by an actuator responding to signals from a control system, which receives feedback from sensors to make fine-tuned adjustments.
Modulating frequency – It refers to the frequency of the signal which varies the instantaneous frequency of a carrier wave in frequency modulation, where the degree of frequency deviation is dependent on the amplitude of the modulating signal.
Modulation frequency – It is the frequency of the original or baseband signal that is used to alter the frequency of a carrier wave. In the process of frequency modulation, the instantaneous frequency of the carrier wave is varied in direct proportion to the amplitude of this modulating signal. The modulation frequency determines the rate at which the carrier’s frequency changes, while the amplitude of the modulating signal determines the amount of frequency deviation.
Modulation technique – It is a method for varying a carrier signal to encode and transmit information. This is done by superimposing a lower-frequency message signal onto a higher-frequency carrier wave by altering the carrier’s amplitude, frequency, or phase. This process enables signals to be sent over long distances through mediums like radio waves or optical fibres.
Modulation transformer – It is part of a radio transmitter which is used to impress modulation on one amplifying stage.
Module – It is a self-contained unit with a specific function and clearly defined interfaces, used to construct larger systems from smaller, manageable parts. This concept, known as modularity, applies to several fields, allowing for increased flexibility, reusability, and maintainability by breaking down complexity. A module can be a physical component, or an assembly of parts which are designed to work together.
Module design – It is an approach which divides a complex system into smaller, independent, and interchangeable components called modules. Each module is designed with a specific function and standardized interfaces, allowing it to be developed, tested, and maintained separately. This method improves flexibility, scalability, and reliability, and is used across different fields.
Modulus – It is the stress needed to produce a certain elongation (strain) normally 100 %. In elastomers, it is a good indication of toughness and resistance to extrusion.
Modulus, initial – It is the slope of the initial straight portion of a stress-strain or load-elongation curve. Modulus of elasticity (E) – It is the measure of rigidity or stiffness of a material. It is the ratio of stress, below the proportional limit, to the corresponding strain. If a tensile stress of 13.8 MPa results in an elongation of 1 %, the modulus of elasticity is 13.8 MPa divided by 0.01, or 1,380 MPa. In terms of the stress-strain curve, the modulus of elasticity is the slope of the stress-strain curve in the range of linear proportionality of stress to strain. It is also known as Young’s modulus. For materials which do not conform to Hooke’s law throughout the elastic range, it is the slope of either the tangent to the stress-strain curve at the origin or at low stress, the secant drawn from the origin to any specified point on the stress-strain curve, or the chord connecting any two specific points on the stress-strain curve is normally taken to be the modulus of elasticity. In these cases, the modulus is referred to as the tangent modulus, secant modulus, or chord modulus, respectively.
Modulus of resilience – It is the quantity of energy stored in a material when loaded to its elastic limit. It is determined by measuring the area under the stress-strain curve up to the elastic limit.
Modulus of rigidity – It is also known as shear modulus. It is the ratio of shear stress to the corresponding shear strain for shear stresses below the proportional limit of the material. Values of modulus of rigidity are normally determined by torsion testing. It is also known as shear modulus.
Modulus of rupture – It is the nominal stress at fracture in a bend test or torsion test. In bending, modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar section modulus.
Modulus of rupture (MOR), Modulus of deformation (refractories) – During thermal stress, normally combined with altered physical-chemical conditions because of infiltration, strain conditions occur in refractory brickwork which can lead to brick rupture or crack formation. In order to determine the magnitude of rupture stress, the resistance to deformation under bending stress (rupture strength) is measured. Determination of the modulus of deformation in the cold state is carried out, together with modulus of rupture, on a test bar resting on two bearing edges. In general, a high ductility is looked for in refractory bricks, i.e., a large deformation region without rupture, which means a high value of the ratio of modulus of rupture to modulus of deformation. The modulus of rupture is defined as the maximum stress of a rectangular test piece of specific dimensions which can withstand maximum load until it breaks, expressed in MPa.
Modulus of rupture in bending (Sb) – It is the value of maximum tensile or compressive stress (whichever causes failure) in the extreme fibre of a beam loaded to failure in bending computed from the flexure equation ‘Sb = Mc/I’, where ‘M’ is maximum bending moment, computed from the maximum load and the original moment arm, ‘c’ is the initial distance from the neutral axis to the extreme fibre where failure occurs, and ‘I’ is the initial moment of inertia of the cross section about the neutral axis.
Modulus of rupture in torsion (Ss) – It is the value of maximum shear stress in the extreme fibre of a member of circular cross section loaded to failure in torsion computed from the equation ‘Ss = Tr/J’, where ‘T’ is maximum twisting moment, ‘r’ is original outer radius, and ‘J’ is the polar moment of inertia of the original cross section.
Modulus of toughness – It is the quantity of work per unit volume of a material needed to carry that material to failure under static loading.
Modulus, secant – It is idealized Young’s modulus derived from a secant drawn between the origin and any point on a non-linear stress-strain curve. On materials whose modulus changes with stress, the secant modulus is the average of the zero applied stress point and the maximum stress point being considered.
Modulus, tangent – It is the slope of the line at a pre-defined point on a static stress-strain curve, expressed in force per unit area per unit strain. This is the tangent modulus at that point in shear, tension, or compression, as the case may be.
Mohr’s circle – It is a graphical representation to visualize the transformation of stresses (normal and shear) on different planes at a point within a stressed body. It essentially allows for the determination of principal stresses, maximum shear stress, and stresses on inclined planes, offering insights into how materials behave under stress.
Mohr-Coulomb criterion – It is a model used in engineering and geology to predict when a material, like soil or rock, is going to fail by shear. It defines the shear strength of a material as the sum of its cohesion (an inherent strength) and a frictional component that is proportional to the normal stress on the failure plane. This relationship is expressed mathematically as T = To + S x tan A, where ‘T’ is the shear stress, ‘S’ is the normal stress, ‘To’ is the cohesion, and ‘A’ is the angle of internal friction.
Mohs hardness – Mohs hardness is defined by how well a substance will resist scratching by another substance. It is rough measure of the resistance of a smooth surface to scratching or abrasion, expressed in terms of a scale devised by the German mineralogist Friedrich Mohs in 1812. The Mohs hardness of a mineral is determined by observing whether its surface is scratched by a substance of known or defined hardness. To give numerical values to this physical property, minerals are ranked along the Mohs scale, which is composed of 10 minerals that have been given arbitrary hardness values. These minerals, in decreasing order of hardness, are diamond -10, corundum – 9, topaz – 8, quartz – 7, othoclase (feldspar) – 6, apatite – 5, fluorite – 4, calcite – 3, gypsum – 2, and talc – 1.
Mohs hardness test – It is a scratch hardness test for determining comparative hardness using 10 standard minerals, from talc (the softest) to diamond (the hardest).
Mohs scale – It is a qualitative, ordinal scale which ranks minerals from 1 (softest) to 10 (hardest) based on their relative scratch resistance. Developed by Friedrich Mohs in 1812, it works by comparing a mineral’s ability to scratch or be scratched by other minerals with known hardness values. This scale is a convenient tool for mineral identification, especially in the field.
Moire pattern – It consists of a pattern developed from interference or light blocking when gratings, screens, or regularly spaced patterns are superimposed on one another.
Moiety – It is a portion of a molecule, normally complex, having a characteristic chemical property.
Moire fringes – These are a large-scale interference pattern of light and dark bands which appears when two repetitive patterns, like gratings or screens, are overlaid at a slight angle, rotated, or have different pitches. They are a visible distortion which can be used to measure displacements and strains in materials and are frequently observed in fields like optics, physics, and even photography because of their interference with patterns in the scene.
Moist air – It is the air which includes the variable component of water vapour, contrasting with dry air, which does not contain water vapour.
Moist environment – It is a setting with high humidity or ample water, which supports specific types of life and processes. This term can describe natural habitats like rainforests which have plenty of water and high humidity, or a controlled setting.
Moisture – It is the water in the liquid or vapour phase.
Moisture absorption – It is the pickup of water vapour from air by a material. It relates only to vapour withdrawn from the air by a material and is to be distinguished from water absorption, which is the gain in weight because of the take-up of water by immersion.
Moisture concentration – It is the weight percentage of water (H2O) present in a hygroscopic environment, which can vary from 0 % to 3 % in increments of 0.5 %. It influences frequency parameters, with higher concentrations leading to a decrease in these parameters, particularly for lower modes.
Moisture content – It is the quantity of moisture in a material determined under prescribed conditions and expressed as a percentage of the mass of the moist sample, i.e., the mass of the dry substance plus the moisture present.
Moisture content measurement – It is the process of quantifying the quantity of water in a material, typically expressed as a percentage of the material’s total mass. It is determined by calculating the ratio of the mass of water to the total mass of the material, and can be measured directly (e.g., by drying a sample) or indirectly using different techniques like electrical resistance, capacitance, or spectroscopy.
Moisture distribution – It is the spatial arrangement or pattern of water content within a material or over an area. It describes how moisture is spread out, which can be uneven and change over time, and is important for understanding how moisture moves through a substance, whether it is a material like soil, or across the earth’s surface.
Moisture diffusion – It is the movement of liquid water and / or water vapour through a product structure, driven by a vapour pressure gradient and influenced by factors such as mass diffusivity, temperature, and boundary conditions. This process occurs simultaneously with heat transfer and is important for moisture removal.
Moisture equilibrium – It is the condition reached by a sample when it no longer takes up moisture from, or gives up moisture to, the surrounding environment.
Moisture exposure – It is the condition of a material or environment being exposed to water, which can be from humidity in the air or direct contact with water, leading to different effects like material degradation, physical damage, or changes in its properties. In materials science, it frequently refers to the process of water absorption that can cause a loss of mechanical strength or other undesirable changes, while in building science, it can refer to mould or damage from leaks.
Moisture in steam – It consists of particles of water carried in steam, expressed as the percentage by weight.
Moisture loss – It is the boiler flue gas loss representing the difference in the heat content of the moisture in the exit gases and that at the temperature of the ambient air.
Moisture management – It is the process of controlling the movement of moisture from one place to another, particularly away from a surface. It refers to the strategies used to prevent water damage from sources like rain and condensation.
Moisture penetration – It refers to the process by which water vapour enters solid materials, potentially leading to changes in their physical, chemical, and mechanical properties. In applications such as thermal insulation, moisture can considerably increase thermal conductivity and decrease thermal resistance, posing challenges for material integrity.
Moisture permeability – It is a material property which measures the rate at which water vapour can pass through a specific area of a substance over a given time and under set temperature and humidity conditions. It quantifies how resistant a material is to the diffusion of water vapour. This property is typically expressed in units like grams per square meter per hour or per 24 hours.
Moisture resistance – It refers to the ability of pellets to withstand moisture adsorption during storage, which can affect their physical strength, energy density, and combustion efficiency. It is typically assessed through a moisture adsorption test, with the equilibrium moisture content (EMC) serving as a key indicator of this resistance.
Moisture retention – It is the ability of a material to hold onto water over time, which is important for soil. It is a measure of how well a substance can absorb and keep moisture, and a higher moisture retention capacity means it can hold more water. This characteristic is important for maintaining hydration and preventing dehydration.
Moisture risk – It is the potential for damage or deterioration caused by excessive moisture, affecting building structures, materials, and indoor air quality. This can lead to several problems like mould growth, corrosion, material decay, and health issues for occupants. It is a key consideration in engineering and construction, with assessments often involving building simulations that analyze how heat, air, and mass transfer in different climates can lead to moisture accumulation.
Moisture sorption – It is the process of a material absorbing or releasing moisture to reach an equilibrium with its surrounding environment at a constant temperature. The relationship between the equilibrium moisture content and the water activity (or relative humidity) is known as a moisture sorption isotherm.
Moisture sorption isotherm – It is a graphical representation which shows the equilibrium relationship between the moisture content of a material and the water activity at a constant temperature. It shows how much moisture a substance absorbs or releases when exposed to different levels of relative humidity, providing insight into its moisture-binding properties. This information is important for determining optimal conditions for storage and processing of products.
Moisture transport – It is the movement of water in its different phases (liquid, vapour) through a medium. This movement is driven by different physical processes, such as diffusion, capillary action, and convection, and is a critical factor in several fields.
Moisture vapour – It is the gaseous form of water, essentially an invisible vapour which is always present in the atmosphere. It is a natural part of the air, and its presence is measured as humidity. It is created through the evaporation or boiling of liquid water and can be transformed back into a liquid through condensation.
Moisture vapour transmission (MVT) – It consists of a rate at which water vapour passes through a material at a specified temperature and relative humidity.
Moisture, workable – It is that range of moisture content within which sand fills, rams, draws, and dries to a satisfactory mould, and within which the sand does not dry out too fast to mould and patch.
Molality – It is the number of moles of solute per kilogram of solvent, serving as a concentration unit which remains independent of temperature and volume changes. It is particularly useful in studying properties related to freezing and boiling points.
Molal solution – It is the concentration of a solution expressed in moles of solute divided by 1,000 grams of solvent.
Molar basis – It refers to the measurement of loading capacity in terms of moles of a substance, indicating that metal-organic frameworks (MOFs) have a high acid gas loading capacity on a molar basis despite potentially lower loading capacity on a mass basis.
Molar composition – It refers to the proportion of a specific component in a mixture, expressed in terms of moles relative to the total number of moles of all components in the system.
Molar concentration – It is the number of moles of a substance per unit volume of solution, typically expressed in moles per litre.
Molar enthalpy – It is the total heat content of a system per mole. It is an extensive property which is calculated by dividing the total enthalpy change (delta H) of a system by the number of moles (n) involved, expressed with the formula ‘delta H/n’. The unit of measurement is typically joules per mole or kilojoules per mole.
Molar entropy – It is the measure of the disorder or randomness in one mole of a pure substance under standard conditions, defined as the entropy per mole of a substance (normally in joules per mole per kelvin). It represents the quantity of thermal energy which is unavailable to do work and helps comparison of the entropy of different substances or predict the spontaneity of chemical reactions. A substance’s molar entropy increases with higher complexity, mass, and a less condensed state (gases have higher entropy than liquids, which have higher entropy than solids).
Molar fraction – It is a measure of concentration which represents the ratio of the number of moles of a specific component to the total number of moles of all components in a mixture. It is a dimensionless quantity, always between 0 and 1, and is calculated using the formula Xi = Ni/N total, where ‘Ni’ is the number of moles of component ‘I’, and ‘N total’ is the total number of moles in the mixture.
Molar Gibbs free energy – It is the change in Gibbs free energy per mole of a substance during a chemical or physical transformation, which helps determine the spontaneity of a process. It is also known as molar free energy and is fundamentally linked to chemical potential, representing the energy available to do work under constant temperature and pressure.
Molarity – It is the number of gram-molecular weights of a compound dissolved in 1 litre of solution.
Molar mass – It is defined as the mass of a given substance divided by the quantity of the substance, and is expressed in grams per mol (g/mol). This makes the molar mass an average of several particles or molecules (potentially containing different isotopes), and the molecular mass the mass of one specific particle or molecule. The molar mass is normally the more appropriate quantity when dealing with macroscopic (weigh-able) quantities of a substance.
Molar percentage – It is the ratio of the moles of a specific component to the total moles of all components in a mixture, expressed as a percentage. It is calculated by multiplying the mole fraction of the component by 100 %. Molar percentage is a way to express the concentration of a solution, similar to volume or mass percent.
Molar solution – It is the aqueous solution which contains 1 mole (gram-molecular weight) of solute in 1 litre of the solution.
Molasses – It is a binding agent used to hold sand grains together to form moulds and cores for casting. It is an economical and environmentally friendly organic binder, especially the blackstrap variety, which can be used in place of expensive synthetic resinous binders. Molasses is a viscous byproduct of the sugar refining process, and when diluted with water, it serves as a non-toxic binding agent for foundry sand.
Mole – One mole is the mass numerically equal (in grams) to the relative molecular mass of a substance. It is the quantity of substance of a system which contains as many elementary units (6.02 × 10 to the power 23) as there are atoms of carbon in 0.012 kilograms of the pure nuclide 12 carbon, the elementary unit is to be specified and can be an atom, molecule, ion, electron, photon, or even a specified group of such units.
Molecular-beam epitaxy (MBE) – It is an epitaxy method for thin-film deposition of single crystals. Molecular beam epitaxy is a vacuum deposition process which is used to form epitaxial films on semi-conductor materials and in the manufacture of semiconductor devices, including transistors. Molecular-beam epitaxy is used to make diodes and MOSFETs (MOS field-effect transistors) at micro-wave frequencies, and to manufacture the lasers used to read optical discs (such as compact disks and digital video disks).
Molecular chain – It is a linear or branched sequence of atoms covalently linked together, very frequently in a polymer. These chains, formed by repeating monomer units, are important since their length, structure, and composition directly determine the bulk physical properties of a material, such as its strength, melting point, and flexibility. Engineers design and manipulate molecular chains to achieve specific material behaviours.
Molecular design – It is an engineering discipline focused on creating molecules with specific properties for targeted applications, such as materials for solar cells. It uses computer-aided design (CAD) and predictive models to identify and optimize new molecular structures, manipulating atoms and functional groups to achieve desired functions like improved energy density.
Molecular diameter – It refers to the estimated physical size of a molecule, which is a key property for applications like gas separation, fluid flow, and materials science. It is not a single, universally fixed value, as different calculation methods exist, such as the kinetic diameter (the effective size for collision) or diameters derived from physical models like the Lennard-Jones potential.
Molecular disorder – It is the lack of perfect organizational uniformity in the arrangement of molecules, which is a key concept in materials engineering for controlling a material’s properties. It is related to entropy, a measure of randomness in a system, and is engineered to create materials with specific beneficial properties like improved flexibility or targeted functionality.
Molecular dynamics simulation – It is a computational method which tracks the physical movements of atoms and molecules over a period of time to model how a system evolves. It works by numerically solving Newton’s laws of motion for a system of interacting particles, using formulas to calculate the forces between atoms and update their positions and velocities at very small-time steps. These ‘virtual experiments’ are used to study a wide range of phenomena, from chemical reactions to the behaviour of bio-molecules, providing insights into a system’s structure, flexibility, and dynamics.
Molecular electronics – It is an inter-disciplinary field of engineering which uses individual molecules or small groups of molecules as the fundamental components of electronic devices, such as wires, transistors, and diodes. This approach is a form of nano-technology which aims to create smaller and more efficient circuits than those possible with conventional silicon technology, extending Moore’s law beyond its current limits. The engineering aspect involves designing, fabricating, and characterizing these molecular-scale components and devices.
Molecular emission – The energetic emitting volume of a spectroscopic source can contain small molecules in addition to free atoms. Like the atoms, the molecules produce optical emission which reflects change in the energies of the outer electrons of the molecule. Unlike the atoms, the molecules have numerous vibrational and rotational levels associated with each electronic state. Each electronic transition in the molecule produces an emission band composed of individual lines reflecting the vibrational and rotational structure of the electronic states involved in the transition. Molecular bands appear in a recorded spectrum as intense edges, out of which develop at higher or lower wave-lengths less intense lines with a spacing which increase with distance from the edge. The edge is the band head. Composed of many closely spaced lines, molecular bands can dominate a region of the spectrum, complicating detection of emission from other species in that region. Emission sources are frequently designed to minimize molecular emission. Less frequently, band intensities are used in place of atomic line intensities to measure concentration.
Molecular engineering – It is a multi-disciplinary field which applies engineering principles to design and create materials and systems at the molecular level. It involves manipulating molecules to achieve specific properties and functions, combining concepts from several disciplines. This can range from building materials from the ‘bottom-up’, one molecule at a time, to designing complex molecular systems for several applications.
Molecular flow – It prevails in the high and ultra-high vacuum ranges. In these regimes the molecules can move freely, without any mutual interference. Molecular flow is present where the mean free path length for a particle is very much larger than the diameter of the pipe.
Molecular formula – It defines a chemical compound by showing the exact number and type of atoms in a single molecule, using chemical symbols with numeric subscripts. For example, the molecular formula for water is H2O, indicating two hydrogen atoms and one oxygen atom. It is distinct from a structural formula, which shows the arrangement of these atoms and bonds, or an empirical formula, which represents the simplest whole-number ratio of atoms.
Molecular fluorescence spectroscopy – It is an analytical technique which measures the fluorescence emission characteristic of a molecular, as opposed to an atomic, species. The emission results from electronic transitions between molecular states and can be used to detect and / or measure trace amounts of molecular species.
Molecular formula – Molecular formulae simply indicate the numbers of each type of atom in a molecule of a molecular substance. They are the same as empirical formulae for molecules that only have one atom of a particular type, but otherwise can have larger numbers. An example of the difference is the empirical formula for glucose, which is CH2O (ratio 1:2:1), while its molecular formula is C612O6 (number of atoms 6:12:6). For water, both formulae are H2O. A molecular formula provides more information about a molecule than its empirical formula, but is more difficult to establish.
Molecular hydrogen – It has chemical formula H2. It is defined as a colourless, odourless, tasteless, and highly flammable di-atomic gas composed of two hydrogen atoms covalently bonded together. It is known for its high diffusion rate and is used in several applications, including as a fuel, in the hydrogenation of oils, and as a coolant because of its low liquid state temperature. Because of its flammability, it needs careful handling, especially when pressurized.
Molecular layer deposition – It is a vapour-phase technique for building ultra-thin films, particularly organic or organic-inorganic hybrid materials, one molecular layer at a time through sequential, self-limiting surface reactions. This process allows for the precise and conformal coating of complex 3D structures, leading to the development of tailored materials for applications in electronics, energy, and biomedical devices. Molecular layer deposition is frequently considered the organic version of ‘atomic layer deposition’ (ALD).
Molecular mass – It is the mass of a given molecule. Units of daltons (Da) are frequently used. Different molecules of the same compound can have different molecular masses since they contain different isotopes of an element. The derived quantity relative molecular mass is the unitless ratio of the mass of a molecule to the atomic mass constant (which is equal to one dalton). The molecular mass and relative molecular mass are distinct from but related to the molar mass.
Molecular mechanics – It is a computational method which uses classical physics to calculate the energy of a molecular system based on the positions of its atoms. It models molecules as a system of balls (atoms) connected by springs (bonds) and uses force fields to describe interactions like bond stretching, bending, and non-bonded forces, allowing for the prediction of properties like molecular shape, flexibility, and relative energies. This technique is widely used in computational studies to simulate large systems like materials.
Molecular mobility – It is the ability of molecules to move or rearrange within a material, and it encompasses different motions like vibration, rotation, and translation. This mobility is a key property that influences a material’s physical characteristics, such as its viscosity, elasticity, and durability. It is affected by factors like temperature and external forces, and understanding it is important for predicting stability and performance.
Molecular morphology – It refers to the shape, size, and arrangement of molecules, especially within a material. It describes the large-scale structure, such as the arrangement of polymer chains in crystalline or amorphous regions, which influences the material’s bulk properties. While it can also describe the supramolecular assembly of polymers, it is not typically used for the structure of individual molecules.
Molecular motion – It is the continuous, random movement of atoms and molecules within a substance because of their kinetic energy. This motion can be in the form of vibration, rotation, or translation (movement from one place to another) and is directly related to temperature, which is a measure of the average kinetic energy. The higher the temperature, the faster and more vigorous the molecules move.
Molecular orbital – It is a region in which one or more electrons can be found in a molecule (as opposed to that within an individual atom).
Molecular orientation – It is the specific arrangement and positioning of molecules in space. It can refer to the alignment of molecules in a solid material, which affects its properties, or the orientation of reactant molecules during a chemical reaction, which determines if a collision is successful.
Molecular properties – These are the physical, chemical, and electronic characteristics of a molecule which are determined by its structure and composition. These properties include things like molecular weight, polarity, and bond angles, and they dictate a molecule’s behaviour, reactivity, and how it interacts with other substances.
Molecular scale – It refers to the size of individual molecules and their interactions, which is typically studied using methods like computational simulations to understand their properties and behaviour. It refers to the size range at which molecular dynamics or Monte Carlo simulations are performed, typically involving a limited number of molecules (100 to 1,000,000) to study their motion and properties based on statistical mechanics.
Molecular seal – It is a seal which is basically of the wind back type, but that is used for sealing vapours or gases. Because of this use, the grooves and lands are dimensioned differently from those of a wind-back seal.
Molecular sieving – It is a separation process using porous materials with uniform pore sizes to selectively filter molecules based on their size and shape. The pores act as a sieve, allowing smaller molecules to pass through while retaining or slowing down larger ones, enabling the separation of mixtures. Common examples of these materials include zeolites, which are alumino-silicates with precisely defined micro-pores.
Molecular size distribution – It is the range of different sizes or molecular weights which exist within a sample of molecules, as no real-world material is composed of molecules of exactly the same size. It is a key parameter for understanding a material’s properties, with its distribution affecting characteristics like performance, processability, and stability. Molecular size distribution is frequently described by average values (such as number-average and weight-average molecular weight) and can be determined using techniques like size exclusion chromatography (SEC).
Molecular spectrum – It consists of the spectrum of electro-magnetic radiation emitted or absorbed by a collection of molecules as a function of frequency, wave number, or some related quantity.
Molecular structure – It is the manner in which electrons and nuclei interact to form a molecule, as clarified by quantum mechanics and the study of molecular spectra.
Molecular velocity – It is the speed at which gas molecules move in random motion, with the most common measure being the root mean square (RMS) velocity, calculated as the square root of 3RT/M, where ‘R’ is the ideal gas constant [8.314 J/(mol·K))], ‘T’ is the absolute temperature in Kelvin , and ‘M’ is the molar mass of the gas in kilograms per mole. This speed is directly proportional to the square root of the temperature and inversely proportional to the square root of the molar mass. Hence, as temperature increases, molecular speed increases, and for gases at the same temperature, lighter molecules move faster than heavier ones.
Molecular weight – It consists of the sum of the atomic weights of all the atoms in a molecule. Atomic weights (and hence molecular weights) are relative weights arbitrarily referred to an assigned atomic weight of exactly 12.0000 for the most abundant isotope of carbon, 12 carbon. The definition of molecular weight is most authoritatively synonymous with relative molecular mass. However, in common practice, use of this terminology is highly variable. When the molecular weight is given with the unit Da, it is frequently as a weighted average similar to the molar mass but with different units. The terms molecular mass, molecular weight, and molar mass can be used interchangeably in less formal contexts where unit-correctness and quantity-correctness is not needed. The molecular mass is more commonly used when referring to the mass of a single or specific well-defined molecule and less commonly than molecular weight when referring to a weighted average of a sample. In case of composites, it is the sum of the atomic weights of all the atoms in a molecule. A measure of the chain length for the molecules which make up the polymer.
Molecular weight measurement – It is the process of determining the mass of a molecule, which is the sum of the atomic masses of all its constituent atoms. It is calculated by adding the atomic weights of every element in the chemical formula and is typically expressed in daltons (Da), or atomic mass units (amu). Molecular weight measurements are important for analyzing complex mixtures like crude oil and can be conducted through techniques involving viscosity data, vapour pressure osmometry, or evaporation loss assessments.
Molecule – It is the smallest portion of a substance which can exist by itself and retain the properties of the substance. Molecules consist of multiple atoms and a particular molecule has a specific number of atoms arranged in a specific way. For example, water is a molecule consisting of two hydrogen atoms and one oxygen atom, the hydrogen atoms are bound to opposite sides of the oxygen atom with an angle of around 104.5-degree between the two hydrogen atoms. A molecule can be thought of either as a structure built of atoms bound together by chemical forces or as a structure in which two or more positively charged nuclei are maintained in some definite geometrical configuration by attractive forces from the surrounding cloud of electrons. Besides chemically stable molecules, short-lived molecular fragments termed free radicals can be observed under special circumstances.
Mole fraction – It is the ratio of the moles of a single component to the total moles of all components in a mixture. It is a dimensionless quantity used to express the composition of a solution or mixture.
Mole number – It refers to the quantity of a substance measured in moles, which is a unit that quantifies the quantity of solute in a solution. It is used in the context of calculating concentrations such as molality, defined as the number of moles of solute per kilogram of solvent.
Mol fraction – It is the ratio of the moles of one component in a mixture to the total moles of all components in the solution mixture.
Mollier diagram – It is the thermodynamic phase diagram for water / steam. The Mollier diagram is a small portion of data from the steam tables graphed onto enthalpy-entropy coordinates.
Molten bath – It is a heated, fluid mixture of salts, metals, or other materials used to uniformly and rapidly heat or clean objects immersed in it. These baths are common in industrial processes for tasks like metal heat treatment (including annealing, nitriding, and carburizing) and descaling, where they provide precise temperature control and rapid heat transfer.
Molten bitumen – It is bitumen which has been heated to a liquid state, making it easier to handle and use for applications like road construction and waterproofing. This process involves heating the viscous, semi-solid bitumen, frequently to temperatures between 140 deg C to 160 deg C, so it can be mixed with aggregates or other materials.
Molten carbonate fuel cell – It is a high-temperature fuel cell which uses a molten carbonate salt mixture as the electrolyte and operates at around 600 deg C to 650 deg C. It converts chemical energy into electrical energy and heat, and its high operating temperature allows it to internally reform hydro-carbon fuels like natural gas or biogas without an external reformer.
Molten glass – It is the glass which has been heated to a high temperature until it liquefies, becoming a hot, thick, and sticky liquid which can be shaped. It is the state of glass after its raw ingredients are fused and before it is cooled and solidified into a solid form.
Molten material – It is a substance which has been heated to a temperature above its melting point, causing it to become a hot, glowing liquid. This term is normally used for materials like rock (lava), metal, or glass which are normally solid but have been liquefied by intense heat.
Molten metal – It refers to metal which has been heated to a liquid state, typically by exceeding its melting point, or produced by reduction of metal oxides at temperatures above the melting point of metal. This liquid metal is then used for casting. The term signifies the metal’s transition from a solid to a liquid due to intense heat.
Molten metal flame spraying – It is a thermal spraying process variation in which the metallic material to be sprayed is in the molten condition.
Molten nitrate salt – It is a liquid state mixture of inorganic nitrate salts, very frequently a blend of sodium nitrate (NaNO3) and potassium nitrate (KNO3). It is used as a heat transfer fluid and a thermal energy storage medium, particularly in concentrated solar power (CSP) plants, because of its high thermal stability, low vapour pressure, and high heat capacity.
Molten phase – It is the liquid state of a substance which has been heated to a temperature above its melting point. It occurs when particles gain enough energy to overcome their fixed positions in the solid structure, allowing them to move more freely. For example, molten iron is liquid iron formed at high temperatures in a furnace, while molten ionic compounds have ions which are free to move and can conduct electricity, which is why they are used in electrolysis.
Molten salt baths – These are anhydrous, fused chemical baths used at high temperatures for a variety of industrial cleaning applications. Among the more common uses of these baths include (i) removal of organic polymers and coatings, (ii) dissolution of sand, ceramic, and glassy materials, and (iii) stripping of plasma carbide coatings. In addition, molten salt baths may be used to pretreat cast iron surfaces before brazing and bonding operations. Molten salt baths for cleaning applications are chemically active or reactive fluids with unique process capabilities. They are quite distinct from other molten salt compositions which are used for simple heat transfer or heat treatment applications. Equipment requirements for successful use of these processes also differ from molten salt heat transfer or heat treatment equipment. Larger volumes of insoluble cleaning by-products are normally formed which are to be effectively and safely collected and removed from the baths.
Molten salt corrosion – It is the rapid degradation of metals when they are exposed to high-temperature molten salts, which can dissolve protective oxide layers and promote electro-chemical reactions. This process can be accelerated by the presence of impurities like moisture or oxygen and results in the formation of sulphides, oxides, and other compounds which weaken the metal structure.
Molten salt electrolysis – It is a process where an electric current passes through a molten salt, causing it to decompose into its constituent elements or compounds. This is done by melting the salt so its ions are free to move and conduct electricity, then using an external power source to force a non-spontaneous chemical reaction. The process is used industrially to produce highly reactive pure metals like sodium and aluminum.
Molten salt reactor – It is a type of nuclear reactor which uses molten salts as either the main coolant, the fuel, or both. Unlike traditional reactors which use solid fuel rods, molten salt reactors can have liquid fuel, where uranium or thorium is dissolved directly into the molten salt. This design offers potential advantages such as passive safety features, higher operating temperatures for higher efficiency, and the ability to operate at lower pressures, reducing risks and construction costs.
Molten state – It is when a solid substance is heated above its melting point and becomes a liquid. In this liquid form, the particles have enough energy to move freely, unlike in their fixed, solid positions. The term is frequently used for materials which are solid at room temperature, such as metals, rocks, and salts, and is the result of a substance melting because of high temperatures.
Molten steel – It is the steel which has been heated to a liquid state, typically around 1,370 deg C, and is used in the casting and shaping of different products. It is the liquid form of steel, created by melting it in a furnace, and is used in foundries and continuous casting machines to pour into moulds to form shapes like slabs, blooms, billets and beams.
Molten weld pool – It is the liquid state of a weld prior to solidification as weld metal.
Molybdate – It is a compound containing an oxyanion with molybdenum in its highest oxidation state of +6 [(O-)-Mo(=O)22−(O-)]. Molybdenum can form a very large range of such oxyanions, which can be discrete structures or polymeric extended structures, although the latter are only found in the solid state.
Molybdenite – It is a mineral consisting of molybdenum di-sulphide (MoS2) which is the main commercial source of molybdenum. It resembles graphite, has a metallic lustre, and is frequently found in thin, platy, or massive forms.
Molybdenum – It is a chemical element. it has symbol Mo and atomic number 42. It is carbide former, and prevents brittleness. It maintains the steel strength at high temperatures. It is present in several steels. Air-hardening steels always have 1 % or more of molybdenum. Molybdenum provides the ability in steel to harden in air. It adds greatly to the penetration of hardness and increases toughness of an alloy steel. It causes steel to resist softening at high temperatures, which defeats the purpose of hot working. If the alloy steel has below 0.02 % molybdenum, then steel can be hot worked with little difficulty. It is used very widely because of its powerful effect in increasing hardenability and also because in low alloy steels, it reduces susceptibility to temper brittleness. It forms stable carbides, raises the temperature at which softening takes place on tempering, and increases resistance to creep. In high-speed steel, it can be used to replace around twice its weight of tungsten. The corrosion resistance of stainless steel is improved by the addition of molybdenum.
Molybdenum addition – It refers to the incorporation of molybdenum into alloys, such as stainless steel and iron aluminides, to improve properties like pitting resistance, corrosion potential, and adhesion of passive films on surfaces. It is shown to have a higher effect on improving these properties compared to other elements like chromium.
Molybdenum carbide – It has chemical formulas are Mo2C.and MoC. It is a hard, refractory ceramic compound of molybdenum and carbon, known for its high melting point, hardness, and corrosion resistance. Because of its unique structure and properties, it is used in applications needing high-temperature and wear resistance, such as cutting tools, and as a catalyst in chemical reactions like hydrogenation.
Molybdenum content – It refers to the quantity of molybdenum present in an alloy, which influences its crystalline structure and properties, such as electro-chemical behaviour and corrosion resistance. Higher molybdenum content can lead to the formation of both crystalline and amorphous phases in the deposit.
Molybdenum deposits – These are natural accumulations of molybdenum-bearing minerals, mainly the mineral molybdenite (MoS2), from which the metal is commercially extracted. These deposits are frequently associated with porphyry copper deposits or are found in large, intrusive granitic rocks. They are mined as either a main source or as a byproduct of copper and tungsten mining.
Molybdenum di-sulphide – It is an inorganic compound with the chemical formula MoS2. It is a transition metal dichalcogenide, meaning it consists of a transition metal (molybdenum) and two sulphur atoms. Molybdenum di-sulphide is known for its layered structure and unique properties, making it a promising material for several applications, including lubrication, catalysis, and electronics.
Molybdenum di-thio-carbamate – It is an organo-molybdenum compound used as an additive in lubricants to reduce friction and wear, improve fuel economy, and protect against extreme pressure. Under the high-pressure, high-temperature conditions of a rubbing surface, molybdenum di-thio-carbamate forms a protective, layered film of molybdenum di-sulphide (MoS2) on the metal, which is highly effective at reducing friction. This compound is widely used in automotive engine oils, industrial lubricants, greases, and metal-working fluids.
Molybdenum mine – It is a site where molybdenum is extracted from the earth, either as the main goal of the operation or as a by-product of copper mining. Molybdenum is mainly mined from molybdenite (MoS2) ore bodies, which are classified as primary mines (molybdenum is the sole objective), by-product mines (copper is the main objective), or co-product mines (both are recovered).
Molybdic oxide – It is a chemical compound, or a family of compounds, consisting of molybdenum and oxygen. The most common form is molybdenum (VI) oxide (MoO3), a yellow or greenish powder which is used as a catalyst, in pigments, and in electronics. Molybdic oxides are also known for their semi-conductor properties and can exist in different oxidation states.
Moment – It is an expression which involves the product of a distance and a physical quantity such as a force or electric charge. Moments are normally defined with respect to a fixed reference point and refer to physical quantities located some distance from the reference point
Moment capacity – It is the ability of a structural element to withstand bending moments without failure, with design equations which are based on failure mechanisms and compared to finite element results to ensure accuracy and safety.
Moment coefficient – It is a value which indicates the effect of loads on a structure, reflecting the internal moments at specific points, and can vary depending on the type of load (positive for hanging loads and reversed for point support loads).
Moment connections – These refer to the locations in a structural frame where beams and columns are joined, allowing the frame to resist bending moments. These connections can be either bolted or welded, depending on the design requirements and seismic considerations.
Moment distribution method – It is a relaxation technique for structural analysis which uses a series of approximations to achieve a desired accuracy, allowing for a quantitative solution to structural problems and improving understanding of the relationship between load and deformation.
Moment equilibrium – It is the condition in which the sum of moments acting on a structure is balanced, ensuring that external forces and moments are in equilibrium along specified directions.
Moment of inertia – Moment of inertia of a rigid body is defined relative to a rotational axis. It is the ratio between the torque applied and the resulting angular acceleration about that axis. It plays the same role in rotational motion as mass does in linear motion. A body’s moment of inertia about a particular axis depends both on the mass and its distribution relative to the axis, increasing with mass and distance from the axis.
Moment parameter – It is the ultimate moment of resistance per unit width of a reinforced concrete slab, which is important for determining its load-carrying capacity under different loading conditions.
Moment-rotation behaviour – It refers to the relationship between the applied moment and the resulting rotation at beam-column connections, which can be classified as pinned, semi-rigid, or rigid. This behaviour is characterized by moment-rotation curves which help assess the stiffness and strength of precast connections under different load levels.
Momentum – It is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction.
Momentum balance – It is a principle derived from Newton’s laws of motion which states the total momentum of a system remains constant unless acted upon by an external force. It is applied in fields like engineering to relate forces to changes in momentum and is used to analyze fluid flow, motion, and other physical processes. Essentially, the rate of change in a system’s momentum is equal to the vector sum of all external forces acting on it.
Momentum balance equation – It is a fundamental principle which states the rate of change of momentum in a system equals the net force acting on it, which is expressed as the sum of external forces (like pressure, gravity, and friction) and the rate of momentum entering and leaving the system. Momentum balance equations express the conservation of momentum in a flow field, balancing momentum fluxes with body and surface forces. These equations can be represented in both point form and vector form and consist of scalar equations valid along Cartesian directions.
Momentum conservation – It is a principle which states that the total momentum of an isolated system remains constant over time, as long as no external forces act upon it. Momentum, defined as an object’s mass multiplied by its velocity (p = m x v), is a vector quantity, and the total momentum of all objects within the system before an event, like a collision, is equal to the total momentum after the event. In fluid dynamics, momentum conservation refers to the principle that the change in momentum of a fluid at a point, influenced by factors such as advection, pressure gradients, viscous stresses, and gravitational forces, is equal to the sum of external and internal forces acting on the fluid.
Momentum diffusion – It normally refers to the diffusion, or spread of momentum between particles (atoms or molecules) of matter, frequently in the fluid state. This transport of momentum can occur in any direction of the fluid flow. Momentum diffusion can be attributed to either external pressure or shear stress or both.
Momentum diffusivity – It is also known as kinematic viscosity. It is a measure of a fluid’s ability to transfer momentum through its viscosity. It quantifies how quickly momentum spreads through a fluid because of the shear stress and molecular motion, and it is defined as the ratio of the fluid’s dynamic viscosity to its density.
Momentum flow rate – It refers to the quantity of momentum per unit time flowing through a given area, which is influenced by the velocity profile in the boundary layer and is less than the rate which occurs without the boundary layer.
Momentum flux – It is the transfer of momentum within a fluid, resulting from the movement of molecules and the interaction between layers of the fluid, influenced by viscosity and shear stress. It describes how momentum is exchanged between a flowing fluid and a solid surface due to friction.
Momentum thrust – It is the force generated by a propulsion system because of the change in momentum of the fluid or mass it expels. It is calculated as the product of the mass flow rate and the change in velocity of the exiting fluid. This force is the main component of a propulsion system’s total thrust and is responsible for moving the object forward.
Monatomic – It is a combination of the words namely ‘mono’ and ‘atomic’, and means ‘single atom’. It is normally applied to gases. A monatomic gas is a gas in which atoms are not bound to each other. Examples at standard conditions of temperature and pressure include all the noble gases (helium, neon, argon, krypton, xenon, and radon), though all chemical elements will be monatomic in the gas phase at sufficiently high temperature (or very low pressure). The thermodynamic behavior of a monatomic gas is much simpler when compared to polyatomic gases because it is free of any rotational or vibrational energy.
Mond process – It is a process for extracting and purifying nickel. The main features consist of forming nickel carbonyl by reaction of finely divided reduced metal with carbon mono-oxide, then decomposing the nickel carbonyl to deposit purified nickel on small nickel pellets.
Monel – It is a group of nickel-copper alloys valued for their high strength, exceptional corrosion resistance, and ability to withstand extreme temperatures. It is composed mainly of nickel and copper, with smaller quantities of iron, manganese, and other elements, Monel is used in demanding applications.
Monel alloys – Monel are a group of alloys of nickel (from 52 % to 67 %) and copper, with small quantities of iron, manganese, carbon, and silicon. Monel alloys are also known as Monel metal. Monel alloys are not cupro-nickel alloys since they have less than 60 % copper. Monel alloys are mainly nickel-copper alloys. There are several types of Monel alloys. The present popular grades are Monel alloy 400, Monel alloy 405, and Monel alloy 500. Monel alloy 400 is also known as ‘Historic Monel’ and ‘alloy 400’.
Monitor-Evaluate-Adjust (M-E-A) cycle – It is an iterative management framework used to improve strategies, projects, and systems. It is a feedback loop which enables continuous learning and adaptation by systematically tracking progress, assessing effectiveness, and making necessary adjustments. This cycle is crucial for ensuring that an initiative stays on track, remains relevant, and achieves its desired outcomes in a dynamic environment.
Monitor function – It is the process which checks the normal operation of a plant and its equipment on a regular basis, providing updates to personnel regarding operational conditions. It includes the ability to detect deviations and activate exception logic to manage failure conditions.
Monitoring – It is the systematic and continuous collection and analysis of information about the progress of a development intervention. Monitoring is done to ensure that all the people who need to know about an intervention are properly informed, and so that decisions can be taken in a timely manner. In a nuclear facility, it is the measurement of radiation levels, concentrations, surface area concentrations or quantities of radioactive material and the use of the results of these measurements to evaluate potential exposures and doses.
Monitoring approach – Under this approach, process parameters and specific consumption at each point of the process is closely monitored to ensure that it does not go off the norms for a long period. In case of notice of any deviation, corrective actions are taken to bring back the process parameters and the specific consumption within the norm. This approach adopts the real time monitoring of the consumption through a centralized control centre.
Monitoring area – It is a defined geographic or virtual space which is systematically observed to collect data for a specific purpose, such as environmental surveillance, cyber-security, or power grid management. The size and boundaries of this area are determined by the scope and scale of what is being monitored, considering factors like the movement of wildlife or the extent of an environmental impact.
Monitoring data – It is the information collected continuously to track and analyze the status, performance, and quality of a system or process over time. This data can be used to ensure accuracy and reliability, detect issues like anomalies or degradation, and inform decision-making. It is used in different fields.
Monitoring instrument – It is a device used to track, measure, and record key process variables or performance indicators. These instruments are used in different fields to provide data for manual oversight or to be integrated into automated control systems. They frequently work in conjunction with software that logs data, provides alerts for critical situations, and visualizes trends through dashboards and graphs.
Monitoring of energy consumption – Continuous monitoring of the energy at various processes has a positive effect on the energy conservation efforts. This monitoring indicates where the process is going off the normal and timely corrective action to bring the process back to normal has a very positive effect towards the energy conservation. These days supervisory control and data acquisition (SCADA) system is used for the energy monitoring. SCADA system gathers all plant site energy information and manages the load dispatch. Energy information to SCADA system is provided by remote PLCs and field instruments. Energy management optimization tools are used for high performance energy process data management and for the recording of time series – both historic and forecasts- of measured and calculated data. For this real time process data is collected from various data acquisition systems through interfaces and stored in the database as time histories.
Monitoring of exposure – It is the systematic measurement of exposure to work related health hazards from, for instance, chemical substances, noise, vibration, or radiation.
Monitoring process – It encompasses a range of activities aimed at improving the operational efficiency by tracking, analyzing, and evaluating key parameters within the organization. The extent to which it is then operationalized depends on the appropriate decision-making by the persons who are level of BPM maturity in the organization.
Monitoring programme – It is a systematic plan which outlines the procedures for assessing the environmental effects of a project, including objectives, implementation, and reporting of results, while relying on accurate baseline information and protocols for interpreting monitoring outcomes.
Monitoring, reporting, and verification (MRV) – It is a systematic process which is used to track, document, and authenticate data related to emissions and other environmental metrics, ensuring transparency and accountability in environmental management and climate action.
Monitoring scheme – It is a systematic process of collecting, analyzing, and using information to track progress toward defined goals and objectives. It involves identifying key indicators, gathering data regularly, and using the resulting information to guide decision-making, ensure a project stays on track, and make necessary adjustments for improvement.
Monitoring sensor – It is a device which detects and responds to changes in its environment by converting a physical input into a signal which can be processed, transmitted, and analyzed. These sensors are used to gather continuous or periodic data on specific parameters such as temperature, pressure, humidity, or power fluctuations to enable real-time monitoring without constant human intervention.
Monitoring signal – It is data collected from a system or device which is analyzed to track its performance, detect anomalies, or predict failures. These signals can be continuous data like vibration, velocity, or voltage, or they can be more abstract indicators like the presence of a power output or the completion of a communication protocol. Analyzing these signals allows for real-time adjustments and proactive maintenance, ensuring the system operates within expected parameters.
Monitoring station – It is a dedicated location or facility equipped with systems to collect, analyze, and potentially transmit data about specific parameters, such as environmental conditions or system performance, for monitoring and surveillance purposes.
Monitoring system – It is a set of processes, tools, and procedures to continuously track and analyze the performance of a system, application, or person. It collects data to provide real-time insights, detect issues, and trigger alerts when parameters fall outside normal ranges, helping to ensure optimal performance and security. These systems are used to make data-driven decisions and improve efficiency.
Monitoring technique – It is a systematic method for observing, collecting data, and analyzing it over time to track the progress of a system, process, or project. These techniques are used to ensure things are functioning correctly, efficiently, and safely, enabling timely decision-making and corrective actions when needed. They can range from simple manual inspections to complex technological solutions like sensors, software, and real-time analytics.
Monitoring wells – These are the wells which are installed for the purpose of collecting samples such as groundwater and soil gas. Analytical results from samples are used to characterize the extent of contamination, the direction of groundwater flow, and the types and quantities of contaminants present in the groundwater.
Monitor nozzle – It is a large, powerful nozzle used in fire-fighting and hydraulic mining which can be manually or remotely directed, rotating 360-degree horizontally and having limited vertical movement. It is designed to deliver a powerful stream or fog of water or foam to combat fires, frequently from a distance, and its effectiveness depends on its design and the specific fire conditions.
Monkey cooler – In a blast furnace, it is the smaller of a series of three water coolers protecting the cinder notch. The largest is the cooler, while the in-between cooler is the intermediate cooler.
Monoacetin – It is also known as glyceryl mono-acetate. It is a liquid chemical compound with the empirical formula C5H10O4, comprising 35 % to 40% monoacetin, 35 % to 40 % diacetin, 10 % to 13 % glycerin, and 9 % to 15 % triacetin in its typical mixture. It is odourless and colourless, with a molecular mass of 134.13 daltons and a boiling point of 280 deg C. It is a mono-glyceride of acetic acid which has several applications, including as an emulsifier, solvent, and in the production of explosives and dyes.
Monatomic gas – It is a gas made up of single, unbonded atoms, like helium or argon. The term ‘mono-atomic’ combines ‘mono’ (one) and ‘atomic’, and these gases have simpler thermodynamic behaviour than di-atomic or poly-atomic gases since they lack rotational and vibrational energy components. They are found as individual atoms since their outer electron shells are full, making them chemically stable and unreactive.
Mono-bloc burners – These are the burners in which the fan and pump are an integral part of the burner forming a single body. Mono-bloc burners are normally used in output ranges varying from tens of kilowatts to several megawatts output.
Mono-block – It is a component or structure which is constructed from a single, solid piece. This term is normally used for integrated units where multiple parts are combined into one integral piece, such as a mono-block pump (where the pump and motor are one unit) or a mono-block engine (where the cylinder head and block are cast as one).
Mono-block pump – It is a type of pump where the motor and pump are integrated into a single unit, mounted on a common shaft. This compact design eliminates the need for a separate coupling and reduces energy loss, making it space-saving, easier to install, and efficient. These pumps are widely used for several industrial applications
Mono-calcium aluminate – It has the chemical formula CaA2O4 (or CaO·Al2O3). It is a mineral and a key component of calcium aluminate cements. It is formed by heating appropriate proportions of calcium carbonate and aluminum oxide, and it melts incongruently at 1,390 deg C. Mono-calcium aluminate is also known for its rapid reaction with water, forming hydrates that contribute to the initial strength development in calcium aluminate cements.
Mono-calcium di-aluminate – It is chemically represented as CaO·2Al2O3. It is a mineral compound composed of calcium oxide (CaO) and aluminum oxide (Al2O3) in a 1:2 molar ratio. It is a type of calcium aluminate and is frequently found in calcium aluminate cements, which are used in several applications like high alumina cement, advanced bio-materials, and cement-polymer composites.
Mono-calcium ferrite – It has formula CaO.Fe2O3. It is a binary calcium ferrite mineral with the chemical formula CaFe2O4. It is a crystalline ceramic material composed of calcium oxide (CaO) and iron(III) oxide (Fe2O3).
Mono calcium hexa aluminate – It is also known as calcium hexa-aluminate or CA6. It is a ceramic material with the chemical formula CaAl12O19. It is a type of calcium aluminate, which are compounds formed by heating calcium oxide and aluminum oxide. CA6 is particularly known for its high structural stability, resistance to alkali corrosion, and its potential in refractory materials and catalyst carriers.
Mono-cast process – It is a specialized casting technique where the entire mould is created as a single, solid piece. This differs from more traditional sand-casting methods, which use separate flasks (the cope and drag) to create the mould. The term is also used to refer to ‘mono-block castings’, such as an engine block cast as a single unit. Mono-cast process (also known as quasi-mono process) is also a method of growing a near-single-crystal silicon ingot using a standard multi-crystalline casting furnace. Unlike the traditional Czochralski (CZ) process, which pulls a single, cylindrical crystal from molten silicon, the mono-cast method places single-crystal ‘seed’ ingots at the bottom of the crucible. As the molten silicon cools, it crystallizes and follows the structure of the seed, resulting in a large, block-shaped ingot with a structure that is predominantly mono-crystalline.
Mono-chromatic – It consists of electro-magnetic radiation having a single wavelength or an extremely small range of wave-lengths, or particles having a single energy or an extremely small range of energies.
Mono-chromatic beam – It is a beam of light or other electro-magnetic radiation that consists of a single wave-length or frequency. In simpler terms, it is light of a single colour. While true single-wavelength radiation is rare, monochromatic beams are typically described as having a very narrow range of wave-lengths.
Mono-chromatic component – It refers to a single wave-length of light in a spectrum. It describes the individual, isolated wave-length passing through a mono-chromator.
Mono-chromatic emissive power – It is the rate at which a surface emits thermal radiation per unit area at a specific wave-length. It is a measure of the energy emitted per second per unit area within a unit wave-length around that specific wave-length. This is different from total emissive power, which is the sum of all radiation emitted over all wave-lengths and directions.
Mono-chromatic, homogeneous – It means of the same wave-length.
Mono-chromatic laser – It is a light source which emits light consisting of a narrow band of wave-lengths, producing light of essentially one wave-length.
Mono-chromatic objective – It is an objective, normally of fused quartz, which has been corrected for use with mono-chromatic light only.
Mono-chromatic wave – It is a wave which has a single frequency and wave-length, meaning it is a ‘pure’ wave of a single colour or tone, unlike poly-chromatic waves (like sunlight) which are a mixture of several wave-lengths. This constant frequency and wave-length mean the wave’s energy, which is directly related to its frequency, also remains constant. Lasers are a common source of highly mono-chromatic light.
Mono-chromator – It is a device for isolating mono-chromatic radiation from a beam of poly-chromatic radiation.
Monoclinic – It means having three axes of any length, with two included angles equal to 90-degree and one included angle not equal to 90-degree.
Monoclinic crystal system – It is one of the seven crystal systems in crystallography. It is characterized by three unequal axes, with two axes perpendicular to each other and the third axis at an oblique angle to the plane formed by the other two. In simpler terms, it has three axes of different lengths, and only two of them are at right angles.
Monoclinic material – It is a type of anisotropic material which has one plane of material symmetry, meaning points on one side are mirror images of points on the other. This symmetry reduces the number of independent elastic constants in its stiffness matrix to 13, down from the 21 found in an ortho-rhombic material. Common examples include minerals like gypsum and orthoclase feldspar, and certain compounds like borax.
Mono-component signal – It is a non-stationary signal characterized by a slow varying amplitude and a positive instantaneous frequency (IF), which involves only one mode of oscillation in each cycle, excluding complex riding waves. Examples include deterministic slow frequency-modulated quasi-harmonic signals and narrow-band random vibration signals.
Monocoque – It is a construction technique where the external shell or skin of an object, like a car body, bears most of the structural load and is integrated with the chassis. This is different from traditional designs that use a separate frame, creating a stronger, lighter, and more rigid structure by making the body panels an integral part of the structural frame. The term comes from the French ‘single shell’, highlighting how the entire body acts as a single, load-bearing unit.
Mono-crystal – It is a solid material with a single, continuous crystal lattice which extends throughout the entire sample, with no grain boundaries. This unique structure eliminates the defects found at grain boundaries, giving mono-crystals superior mechanical, optical, and electrical properties which are important for applications in electronics and optics. Examples include high-efficiency solar cells and turbine blades.
Mono-crystalline – It describes a solid material composed of a single, continuous crystal structure throughout its entire mass. This single-crystal structure, frequently made from highly purified silicon, is highly uniform, allowing electrons to have higher freedom of movement, which leads to higher efficiency in applications like solar cells.
Mono-crystalline diamond – It is a synthetic diamond with a single, continuous crystal structure, making it exceptionally hard and durable. Produced using high-pressure / high-temperature (HPHT) methods, it possesses properties similar to natural diamond, like high thermal conductivity and wear resistance. Its uniform, single-crystal structure allows for the creation of atomically sharp cutting edges, making it valuable for high-precision applications like micro-milling, lapping, and polishing.
Mono-crystalline silicon – It is a form of silicon where the entire solid is a single, continuous crystal, making its atomic structure uniform and free of grain boundaries. This property makes it ideal for electronics and high-efficiency solar cells since it allows for superior electrical conductivity and charge carrier flow. It is manufactured by growing a large single crystal, called an ingot, from molten silicon using methods like the Czochralski process, which is then sliced into wafers.
Mono detail drawing – It is a technical drawing which defines a single part completely. It provides all necessary information for manufacturing that specific part, including its configuration, dimensions, tolerances, materials, and finishes, on a single sheet. This is in contrast to a multi-detail drawing, which shows two or more related parts on one sheet.
Mono-ethanol-amine (MEA) – It is a naturally occurring organic chemical compound with the formula HOCH2CH2NH2 or C2H7NO. The molecule is bifunctional, containing both a primary amine and a primary alcohol. It is a colourless, viscous liquid with an odour reminiscent of ammonia.
Mono-filament – It is a single, continuous strand of synthetic or metallic material produced by extruding a melted polymer through a die, then cooling, stretching, and annealing it. It is known for its durability, strength, and defined geometry, making it suitable for applications such as technical textiles for filtration and screen printing, high-strength ropes.
Mono-hydrate – It is a chemical compound which contains one molecule of water for every molecule of the main substance. This water molecule is referred to as water of hydration and is incorporated into the crystal structure of the compound. It is represented by writing the substance’s chemical formula followed by a dot and ‘H2O’, for example, Salt.H2O.
Mono-layer – It is the basic laminate unit from which cross-plied or other laminate types are constructed. It is also, a ‘single’ layer of atoms or molecules which is adsorbed on or applied to a surface.
Mono-layer coating – It is a single, closely-packed layer of molecules or atoms deposited on a surface to alter its properties, such as for corrosion protection or improved dispersion of nano-particles. These coatings can be applied through techniques like electro-plating or self-assembly, which creates self-assembled monolayers (SAMs) which are crucial for several applications.
Monolithic construction – It is a method where a structure, or a large section of it, is built as a single, continuous piece, frequently by casting concrete without joints. This creates a more seamless, unified structure which is stronger and more resilient than traditionally assembled buildings, using techniques like pouring concrete for walls, floors, and roofs at once.
Monolithic integrated circuit – It is an electronic circuit built on a single piece of semiconductor material, typically silicon, where all components like transistors and resistors are fabricated and interconnected within that single crystal. The term ‘monolithic’ comes from Greek words meaning ‘single’ and ‘stone’, signifying the circuit is formed from a single piece of material, similar to a sculpture carved from a single block. This approach allows for high-density, high-speed circuits which that are small and reliable.
Monolithic material – It is a single, continuous piece of material with no joints or seams, analogous to a ‘single stone’. This term applies to different fields, from large structures like concrete walls to micro-scale components like integrated circuits. The lack of joints provides superior strength and durability compared to assembled or composite materials.
Monolithic micro-wave integrated circuit – It is an integrated circuit which operates in micro-wave frequencies and which can be fabricated by printed circuit board technology.
Monolithic refractories – Monolithic refractories are special mixes or blends of dry granular or cohesive plastic materials used to form virtually joint free linings. They are unshaped refractory products which are installed as some form of suspension that ultimately harden to form a solid mass. Most monolithic formulations consist of large refractory particulates (an aggregate), fine filler materials (which fill the inter particle voids) and a binder phase (that gels the particulates together in the green state). Types of these refractories are castable refractories, insulating castables, plastic refractories, ramming mixes, patching refractories, coating refractories, mortars, gunning and fettling mixes etc. Monolithic refractories represent a wide range of mineral compositions and vary greatly in their physical and chemical properties. Some are low in refractoriness while others approach high purity brick compositions in their ability to withstand severe environments. Various means are employed in the placement of monolithic refractories like ramming, casting, guniting, spraying, and sand slinging etc.
Monomer – It is a simple molecule capable of combining with a number of like or unlike molecules to form a polymer. It is a repeating structure unit within a polymer. It is a single molecule which can react with like or unlike molecules to form a polymer. It is the smallest repeating structure of a polymer (mer). For addition polymers, this represents the original unpolymerized compound.
Monomer concentration – It is the measure of the quantity of monomer molecules dissolved in a solution, typically expressed in moles per litre (molarity). This concentration is a critical parameter which influences reaction rates, polymer properties, and product characteristics, such as the thickness, pore size, and cross-linking degree of a membrane. Optimizing monomer concentration is necessary for controlling polymerization processes and achieving desired polymer structures.
Monomer molecules – These are small molecules which combine to form larger chemical compounds known as polymers, through simple repeating structures and covalent bonds.
Mono-molecular – It describes something with the thickness of a single molecule, such as a mono-molecular film which is a layer one molecule thick, frequently formed on a surface. It can also refer to a mono-molecular reaction, a chemical reaction which involves a single molecule rearranging to form one or more product molecules.
Mono-olefins – These are a type of alkene, which are hydrocarbons (compounds made of hydrogen and carbon) containing one carbon-carbon double bond. They are also referred to as monoalkenes or simply olefins. The general formula for acyclic (non-cyclic) mono-olefins is CnH2n, meaning there are twice as many hydrogen atoms as carbon atoms in the molecule. Alkenes are a class of unsaturated hydrocarbons which contain at least one carbon-carbon double bond (C=C). When an alkene has only one carbon-carbon double bond, it is called a mono-olefin or mono-alkene.
Mono-pile foundation – It is a single, large-diameter steel pipe driven or drilled into the seabed to support an offshore structure, very frequently a wind turbine. It consists of a hollow cylindrical shaft embedded in the soil and a transition piece above the seabed which connects to the tower. This deep foundation design transfers all loads from the structure, such as wind and wave forces, to the soil through its large diameter and depth.
Mono-ply belt – Mono-ply belt has single ply carcass. The one-ply carcass provides over 2,000 kilo newtons per meter tension. It has low elongation which allows short take-up strokes. Single layer carcass structure provides optimum troughing as well as provides high bendability hence, allowing small-diameter pulleys. Besides high bendability, the belt has impact-resistance. The thin carcass allows thick cover rubber layers, extending belt life span.
Mono-rail – It is a railway system which uses a single rail as its track, which can be elevated or at ground level. The term can also refer to the track beam or the vehicles which travel on it. There are two main design types namely top-running, where the vehicle’s wheels run on top of the rail, and suspended, where the vehicle hangs from the rail.
Monoscope – It is a raster scan video device which generates a single fixed image for test or identification purposes.
Monotectic – It is an isothermal reversible reaction in a binary system, in which a liquid on cooling decomposes into a second liquid of a different composition and a solid. It differs from a eutectic in that only one of the two products of the reaction is below its freezing range.
Monotectic equilibrium – It refers to a three-phase reaction where a liquid phase decomposes into a solid phase and a different liquid phase upon cooling. This involves a miscibility gap where two liquid phases are immiscible and coexist, like oil and water. The reaction can be represented as L1 = L2 + S, where ‘L1’ is the initial liquid, ‘L2’ is the second liquid phase, and ‘S’ is the solid phase.
Monotone loading – It is a type of loading which involves a monotonically increasing load applied to a structure until a specific level is reached or mechanical failure occurs.
Monotonic loading – It is a testing procedure in which the load on the sample progressively increases or decreases, but does not oscillate in value.
Monotron – It is an instrument for measuring indentation hardness. It is fitted with two dials, one to measure depth of penetration, the other the load.
Monotron hardness test – It is an obsolete method of determining indentation hardness by measuring the load needed to force a spherical penetrator into a metal to a specified depth.
Monotropism – It is the ability of a solid to exist in two or more forms (crystal structures), but in which one form is the stable modification at all temperatures and pressures. Ferrite and martensite are a monotropic pair below the temperature at which austenite begins to form, e.g., in steels. Its alternate spelling is monotrophism.
Mono-valent – It mainly refers to a substance (atom, ion, or functional group) which has a valence of one. This means it can form only one chemical bond or carries a single positive or negative charge.
Mono-valent alkali metal – It is an element from Group 1A of the periodic table (like sodium and potassium) which readily loses its single valence electron to form a +1 ion. These metals are known for their high reactivity and are used in applications such as batteries, as well as in the production of glass and soap. Their chemical properties are exploited in processes like ion exchange and their unique structural properties are studied in areas like materials science and soil mechanics.
Mono-valent ion – It is an atom, ion, or chemical group with a valence of one, meaning it can form a single bond or has a single positive (+1) or negative (-1) charge. This single charge is either a result of losing one electron to form a cation or gaining one electron to form an anion. Common examples include sodium (Na+) and chloride (Cl-) ions.
Monsoon – It is traditionally a seasonal reversing wind accompanied by corresponding changes in the precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscillation of the Intertropical Convergence Zone (ITCZ) between its limits to the north and south of the equator. The term monsoon is normally used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is also sometimes used to describe locally heavy but short-term rains.
Monte Carlo analysis – It is a mathematical technique which uses repeated random sampling to model the probability of different outcomes in uncertain events, providing a range of possible results and their likelihood. It is used in fields like project management, and engineering to assess risk by simulating numerous scenarios based on variables with probability distributions. By running thousands of iterations, it gives a clearer picture of what can go wrong than a single-point analysis.
Monte Carlo approach – It is a computational method which uses repeated random sampling to solve complex problems with uncertainty. Instead of a single analytical solution, it generates a multitude of possible outcomes by simulating a system with random inputs, allowing engineers to estimate a range of results and their probabilities. This method is widely used to model everything from structural formation to complex systems, since it embraces randomness to find probable solutions.
Monte Carlo model – It is a computational technique which uses random sampling to simulate a range of possible outcomes for an uncertain event. It is used in several fields to model complex systems, assess risk, and make predictions by repeatedly running simulations with different inputs. The core idea is to represent uncertain variables with probability distributions and then generate numerous random samples from those distributions to explore a wide array of potential scenarios.
Monte Carlo sampling technique – It is a computational method which uses repeated random sampling to get numerical results for problems with uncertainty. Instead of solving for a single outcome, engineers simulate a system several times by generating random inputs based on probability distributions to estimate the range of possible outcomes. This approach is especially useful for problems which are too complex to solve analytically, such as estimating cost and schedule risks in projects or modeling physical processes like thermal radiation.
Monte Carlo simulation – It is a method of generating information for a simulation when events occur in a random way. The Monte Carlo method uses unrestricted random sampling in a computer simulation in which the results are run off repeatedly to develop statistically reliable answers.
Monte Carlo techniques – It consists of calculation of the trajectory of incident electrons within a given matrix and the pathway of the X-rays generated during interaction.
Monticellite – They are gray silicate minerals of the olivine group with compositions CaMgSiO4 and CaFeSiO4, respectively. Most monticellites have the pure magnesium end-member composition but rare ferroan monticellites and magnesio-kirschsteinite are found with between 30 mol. %and 75 mol. % of the iron end member.
Months of inventory – It is the ratio of the end-of-period inventory to average monthly level of sales for the period.
Montmorillonite – It is a soft, clay mineral known for its ability to absorb large quantities of water and swell significantly. It is a phyllosilicate, meaning it has a layered structure, and is a major component of bentonite clay. Montmorillonite’s unique properties, such as high surface area, cation exchange capacity, and swelling ability, make it valuable in several applications.
Moody’s friction factor – It is a dimensionless quantity used in fluid mechanics to represent the resistance to flow in a pipe due to friction. It is defined graphically by the Moody diagram, which plots the friction factor against the Reynolds number for different levels of pipe relative roughness. The Moody friction factor is used to calculate pressure drop and head loss in pipes.
Moonbeam – It is a device attached to the end of a lead brace which allows a pile to be driven with a side batter.
Moore’s law – It is the observation that the number of transistors possible in an integrated circuit doubles approximately every two years.
Mooring chain – It is a heavy-duty, interconnected steel chain designed to anchor floating vessels and offshore structures to the seabed. These chains are critical components in mooring systems, engineered for high tensile and fatigue resistance, and exceptional corrosion resistance, making them suitable for harsh marine environments. They are made from grades of high-strength low-alloy (HSLA) steel, and their strength is classified by grades such as R3, R4, and R5, with properties defined by standards like the ‘minimum breaking load’ (MBL).
Morphological features -These refer to the observable characteristics of a material or system’s structure, shape, and form, which can be studied at different scales from microscopic to macroscopic. This can include the physical features of a material’s surface or internal structure, as well as the shapes of objects in digital images or the parameters of a design solution. Analyzing morphological features is important for understanding a material’s properties, performance, and behaviour.
Morphological matrix – In a formalized process for developing design concepts, it is a list of all functions needed by the design, including all of the conceivable ways of accomplishing each function.
Morphology – It is the characteristic shape, form, or surface texture or contours of the crystals, grains, or particles of (or in) a material, normally on a microscopic scale. It is the overall form of a polymer structure, i.e., crystallinity, branching, molecular weight, and so on.
Morphotropic phase boundary – It is the compositional interface in a solid solution where two distinct crystal phases coexist, leading to a significant improvement of material properties, particularly piezoelectric and dielectric constants. This occurs since the material’s structure is unstable at the boundary, which allows for higher polarization movement and improved electro-mechanical coupling. The morphotropic phase boundary is critical for engineering high-performance piezoelectric materials used in sensors, actuators, and other transducers.
Morse code – It is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy. Morse code is a method of transmitting text by long and short impulses and varying delays between them.
Mortar mix – It is a blend of a binder (like cement or lime), a fine aggregate (such as sand), and water, used to bond masonry units like bricks, stones, or blocks. The mix is designed to be a pliable paste that hardens into a strong, durable material, providing structural cohesion while distributing load and creating a weathertight joint. The specific proportions of a mortar mix are determined by factors like the type of masonry, the needed strength, and the application.
Mortars – Mortars are normally neither classified under refractory brick nor monolithic refractories. These are finely ground refractory materials, which become plastic when mixed with water. These are used to bond the brickwork into solid unit, to provide cushion between the slightly irregular surfaces of the brick, to fill up spaces created by a deformed shell, and to make a wall gas-tight to prevent penetration of slag into the joints. Mortars must have good water retention properties and must not sediment. In this way, premature penetration of water in the refractory bricks after laying, causing the mortar to dry out, can be avoided. Refractory mortars can be with ceramic bonding (bonding starting at 800 deg C), chemical bonding or hydraulic bonding (bonding starting at 20 deg C). The composition and characteristics of the mortar materials, grain size and consistency are the important properties of the mortars.
Mosaic crystal – It is an imperfect single crystal composed of regions which are slightly disoriented relative to each other.
Mosaic structure – In crystals, it is a sub-structure in which adjoining regions have only slightly different orientations.
Moscovium – It is a synthetic, superheavy, and radioactive chemical element with atomic number 115, named in honour of the Moscow region of Russia where it was first synthesized. It is extremely unstable, with a very short half-life, and only a few atoms have been created, which decay almost instantly into lighter elements.
MOSFET – It is metal oxide semi-conductor field effect transistor, a class of transistor using a single type of charge carrier and with a very thin insulating layer between current channel and control gate. If a person counts those built into integrated circuits, nearly all transistors are MOSFETs.
Mossbauer effect – It is the process in which gamma-radiation is emitted or absorbed by nuclei in solid matter without imparting re-coil energy to the nucleus and without Doppler broadening of the gamma-ray energy.
Mossbauer spectroscopy – It is an analytical technique which measures recoilless absorption of gamma-rays which have been emitted from a radioactive source as a function of the relative velocity between the absorber and the source.
Mossbauer spectrum – It is a plot of the relative absorption of gamma-rays against the relative velocity between an absorber and a source of gamma-rays.
Most penetrating particle size – It is the particle diameter which a filter is least efficient at capturing. This size is the result of a balance between different filtration mechanisms namely larger particles are more easily captured by inertial impaction, while smaller particles are more effectively captured by Brownian diffusion. The MPPS is the particle size where neither mechanism dominates, making it the most likely to pass through the filter. For several air filters, the most penetrating particle size is typically between 0.1 micrometers and 0.4 micrometers.
Most probable failure point – It is the point on the boundary between ‘safe’ and ‘failure’ which is closest to the origin in a normalized space, representing the combination of random variables which has the highest probability of failure. It is a critical concept in structural reliability analysis, used with methods like the ‘first-order reliability method’ (FORM) to estimate the risk of a system failing and to identify the most significant uncertainties in the design.
Mother board -It is the central printed circuit board (PCB) which acts as the computer’s backbone, connecting all major components like the CPU (central processing unit), RAM (random-access memory), and expansion cards, and providing power and a communication pathway between them. It is a critical component which allows the processor to interact with storage, graphics, and peripheral devices, and it is to be engineered to support specific protocols and hardware combinations.
Mother liquor – It is also known as spent liquor. It is the solution remaining after a component has been removed by a process such as filtration or more commonly crystallization. It is encountered in chemical processes.
Motion – It is defined as the change in position of an object with respect to time and its surroundings. It is a fundamental concept which describes movement, whether it is a simple change in location or a more complex shift in orientation.
Motion control – It is that part of automation which deals with accurately controlling the movements of machines.
Motion conversion actuators – These actuators are generally used to adapt a common translational motion from the actuator’s output to a rotary valve. The rod which moves axially from the translational motion actuator is connected to a disk and the connection is pivoted. The disk itself is also pivoted about its centre. This system of pivots allows the translational motion to be converted into the rotation of the disk, which opens or close the rotary valve. The main advantage of this set-up is that an inexpensive translational motion actuator can be used with rotary valves. The key draw-back is that the applications in which this can be used is very limited. Specifically, this set-up is useless in the common case where the rotary motion needed is greater than 90-degree.
Motion parameters – These are the quantitative measures used to describe an object’s movement, such as its position, velocity, and acceleration, as well as rotational and translational parameters. They can also refer to specific parameters which define a system’s motion, like the tool path in manufacturing or seismic intensity for earthquakes, and are necessary for analyzing, controlling, or reconstructing motion in several applications.
Motion resistance – It is the force which opposes or hinders movement. It is a general term encompassing several forces which act against an object’s motion, such as friction, air resistance, and rolling resistance. These forces can cause an object to slow down, stop, or change direction. In case of a conveyor system, it consists of the resistances namely main, additional, inclination, and special, when moving a conveyor belt on a conveyor system.
Motion simulation – It is a computer-based process which analyzes and predicts the movement of mechanical systems. It uses techniques like kinematics and dynamics to simulate how parts move, interact, and behave under different conditions, providing detailed quantitative information on things like position, velocity, acceleration, and forces. This allows engineers to create virtual prototypes and test designs without physical models, which helps in optimizing performance and avoiding costly mistakes before building the final product.
Motivational engineering – It is a field which uses principles of motivation science to understand and influence the behaviour of professionals to achieve organizational goals. It involves recognizing that motivation is driven by both internal factors (like interest and satisfaction) and external factors (like pay and recognition) and then applying this understanding to create systems that foster commitment, focus, and high performance.
Motive fluid – It is a high-pressure fluid (like steam) which provides the energy to produce motion or flow in another fluid or system. It is used in devices such as ejectors to convert its static pressure energy into kinetic energy, creating a suction flow to move other substances, and in steam engines to do mechanical work.
Motive force – It is the force which causes motion or is applied in the direction of motion, while resistant force is the force acting in the opposite direction. The term also refers to more specific concepts like electro-motive force (EMF) in electrical circuits and magneto-motive force (MMF) in magnetic circuits. Motive force is to be higher than resistant force for an object to accelerate, and the two forces are equal if the object moves at a constant velocity.
Motive power – It is the source of energy needed to drive mechanical movements in machines, such as hydraulic oil in injection moulding machines, which is pumped at high pressure to actuate cylinders and motors.
Motor – It a device which uses petrol, gas, and electricity etc. to produce movement and makes a machine work. A motor converts electric, pneumatic or fluid power into mechanical force and motion, normally a rotating shaft output. It is a prime mover.
Motor alignment adjustment – It involves the meticulous positioning of equipment motors to guarantee efficient power transmission. It is imperative to conduct regular inspections and fine-tune the alignment to sustain optimal motor performance.
Motor control centre (MCC) – It is an assembly to control some or all electric motors in a central location. It consists of multiple enclosed sections having a common power bus and with each section containing a combination starter, which in turn consists of motor starter, fuses or circuit breaker, and power disconnect. A motor control centre can also include push buttons, indicator lights, variable-frequency drives, programmable logic controllers, and metering equipment. It can be combined with the electrical service entrance for the building.
Motor controller – It is the electrical apparatus which regulates and protects an electric motor, which can be as simple as an on-off switch or a servo system for precision machine tools.
Motor drive – It is the system in which the motor is located and makes it spin. It is called the drive, and is also referred to as the electric drive or motor drive. In general, it is the device which controls the motor. Drives designed for electric motors are also called electric drives.
Motor efficiency – It is the ratio of a motor’s useful mechanical output power to its electrical input power, measuring how effectively it converts electrical energy into mechanical energy. It is calculated as the output power (Pout) divided by the input power (Pin), i.e., N = Pout/Pin, or by subtracting losses (Ploss) from the input power, i.e., N = Pin – Ploss)/Pin. This ratio is always less than 100 % since some energy is lost as heat, friction, and other factors during the conversion process.
Motor-generator (MG) set – It is a set of machines which consists of one or more motors mechanically coupled to one or more generators. In motor generator set, the generator delivers direct current of appropriate amperage and voltage.
Motor inertia – It is a measure of a rotating object’s resistance to changes in its rotational speed, influenced by its mass and how that mass is distributed. It determines how much torque is needed to accelerate or decelerate the motor, and it is calculated using a formula which considers the mass and distance from the axis of rotation. Engineers are to account for motor inertia when designing systems to ensure proper performance, efficiency, and controllability.
Motor insulation – It is the material which prevents electrical short circuits and protects the motor’s windings from electrical stress, heat, and contamination. It is critical for safety, efficiency, and longevity, and is frequently categorized by an insulation class, which indicates the maximum temperature the material can withstand during operation.
Motorized pulley inspection – It is a compact, motor-driven pulley integral to the conveyor system, needing periodic inspections for proper functioning, lubrication, and overall health.
Motorized roller conveyor system – It is a conveyor system with rollers powered by individual motors. Regular inspections are essential for assessing roller and motor health, alignment, and overall functionality.
Motor octane number – It measures a gasoline’s resistance to knock under high-speed, high-temperature conditions which simulate highway driving. It is determined using a specific single-cylinder test engine under strenuous conditions (900 revolutions per minute engine speed, 149 deg C intake temperature). Since motor octane number is a more critical indicator of a fuel’s performance under load, it is typically 8 to 12 points lower than the Research Octane Number (RON) and is not displayed on fuel pumps.
Motor oil – It is a specialized lubricating fluid for internal combustion engines, formulated with base oils (either mineral or synthetic) and a blend of additives to reduce friction and wear, cool engine parts, clean the engine of deposits, and protect against corrosion. Its performance is critical for engine longevity and efficiency, and it is characterized by properties like viscosity, which can change depending on temperature.
Motor power – It is the mechanical energy output per unit of time, calculated as the product of torque and rotational speed. It represents the rate at which a motor performs work and is typically measured in horsepower (HP) or kilowatts (kW). Choosing the correct motor power is necessary for equipment operation to ensure efficiency and prevent overload or wasted energy.
Motor torque – It is the twisting or rotational force a motor produces. It is a measure of the force which can cause an object to rotate around an axis, and it directly relates to a motor’s ability to accelerate quickly or perform heavy work, such as pulling a heavy load or climbing a steep hill. Torque is measured in newton-meters (Nm).
Motorized variac – It is a type of variable autotransformer which uses a motor to automatically and remotely adjust the output alternating current voltage, offering precise and continuous control without manual intervention. Unlike a standard variac with a manual knob, a motorized version adds convenience and precision, making it ideal for applications requiring remote control or continuous adjustments in settings like industrial testing, laboratories, and other electrical applications.
Motor operated (MO) – The term is used for valves which are operated by an electric motor.
Motor soft starter – It is a device which reduces the inrush current when an electric motor is first connected to the power supply.
Mottled cast iron – It is the iron which consists of a mixture of variable proportions of gray cast iron and white cast iron. Such a material has a mottled fracture appearance.
Mottled iron – It is also known as mottled cast iron. It is a type of cast iron which shows a distinctive, mottled or marbled appearance because of the uneven distribution of graphite within its structure. This characteristic appearance arises during the solidification process when some areas cool and solidify as white cast iron (cementite) while others solidify as gray cast iron (graphite).
Mottling, pressure – It is non-uniform surface appearance resulting from uneven pressure distribution between adjacent layers of the product.
Mould – It is the part or parts making up the confining form in which a powder is pressed or a sintered compact is repressed or coined. The term is frequently used to mean mould assembly. In case of composites, it is the cavity or matrix into or on which the plastic composition is placed and from which it takes form. It is also to shape plastic parts or finished articles by heat and pressure. It is the assembly of all the parts which function collectively in the moulding process.
Mouldability – It refers to the ability of the moulding sand to be compacted uniformly and shaped around a pattern, and to hold that shape to create a stable mould cavity. It is a critical property for producing high-quality, defect-free metal castings.
Mouldability controller – It is a patented device used to maintain the consistent ‘moldability index’ of the sand mix. This is critical for achieving reliable and high-quality castings, especially in sand casting processes.
Mouldable ceramic fibre – It is also called mouldable refractory ceramic fibre. It is ceramic fibre with inorganic and / or organic binder which can be moulded.
Mouldable refractory – It is the unshaped refractory, supplied ready for use, with a high workability, made up of aggregate, bond and liquid, and which hardens after placing by the action of heat. As per the type of product, the main bond can be ceramic, chemical, or organic. Plastic refractory materials are normally supplied in soft, pre-formed blocks or slices and placed by ramming (mechanical or manual).
Mould base – It is the structural foundation of an injection mould which houses and supports the mould’s working components, like the cavities and cores. It provides the framework for the ejection system, ensures precise alignment, and is used to attach the mould to the injection moulding machine. Essentially, it is the ‘skeleton’ which holds everything together while the core inserts create the final product shape.
Mould blower – It is a moulding equipment for blowing sand mixture onto the pattern with compressed air. It allows for faster production than gravity roll-over dump.
Mould cavity – It is the precisely shaped void within a mould which is filled with molten metal to form a casting. It is the impression left after a pattern, a replica of the final part, is removed from the compacted moulding material, such as sand. This cavity has the exact shape of the desired casting’s external surface.
Mould coating – It is a liquid-based suspension of refractory materials applied to a mould or core to create a smooth, protective barrier between the molten metal and the mould surface. This coating prevents the molten metal from penetrating the porous mould, reduces casting defects, and results in a cleaner, more accurate final casting. The liquid evaporates, leaving a thin, uniform layer of refractory material.
Mould conveyor – It is a system which moves sand moulds horizontally from stations like pouring to others like solidification or shakeout. These systems can be belt-based, walking-type, or resonance channels, designed for the specific needs of moving moulds efficiently and safely through the foundry process, frequently including features for cooling, cooling, and transferring moulds with castings.
Mould, continuous casting machine – Moulds play an important role in the process of continuous casting of liquid steel. They are the heart of the continuous casting process. In the process of continuous casting, liquid steel is poured from the tundish into the casting mould through the submerged entry nozzle (SEN) immersed in the liquid steel. The moulds are water cooled. Solidification of liquid begins in the mould by indirect cooling. The cooling process in the mould is known as primary cooling process. The mould is basically an open-ended box structure, containing a water-cooled inner lining fabricated from a high purity copper alloy. Small quantities of alloying elements are added to increase the strength. Mould water transfers heat from the solidifying shell. The working surface of the copper face is frequently plated with chromium or nickel to provide a harder working surface, and to avoid copper pickup on the surface of the cast strand, which can facilitate surface cracks on the cast steel. The depth of the mould can range from 0.5 metre to 2 metre depending on the casting speed and section size.
Mould cover half – It is known as the cope. It is the top half of a two-part moulding flask, which is a container used to hold the casting sand. The bottom half is called the drag.
Mould dimensions -These are the measurements of a mould, such as its length, width, and depth, which are determined by the product’s geometry and are to account for material shrinkage. In casting, mould dimensions can refer to the specific measurements of the cast product, like slabs, blooms, or billets, which affect the surface-to-volume ratio.
Moulded edge – It is an edge which is not physically altered after moulding for use in final form, and particularly one which does not have fibre ends along its length. In case of a conveyor system, it is the solid rubber belt edge formed in a mould or against edge irons. Another option is cut edges. The technical differences are small. Steel cord conveyor belts always have moulded edges.
Mould filling – It is the process where molten or liquid material is injected into a mould cavity to form a specific shape. This stage is critical in manufacturing, particularly for plastics, rubber, and metal casting, and involves carefully controlling factors like pressure, temperature, and injection speed to ensure the material fills the mould completely and uniformly before it solidifies. A key part of this process is the material displacing air to prevent defects like voids and air traps.
Moulded interconnect device (MID) – It is an injection-moulded thermo-plastic part with integrated electronic circuit traces. The use of high temperature thermo-plastics and their structured metallization open a new dimension of circuit carrier design to the electronics industry This technology combines plastic substrate / housing with circuitry into a single part by selective metallization.
Moulded net – It is the description of a moulded part which needs no additional processing to meet dimensional requirements.
Moulded part – It is a component formed by using a mould to shape a pliable material, such as plastic or metal. This manufacturing process, known as moulding, creates complex geometries through methods like injection moulding, blow moulding, or compression moulding, resulting in high-volume, high-accuracy parts used in industries ranging from automotive to electronics.
Moulded product – It is an item manufactured by shaping a pliable or liquid raw material into a specific form using a rigid frame called a mould. This process uses a mould to create multiple copies of an object after the material cools and hardens inside the mould.
Moulded surface – It refers to the exterior finish of a manufactured part made by a moulding process, like injection moulding, which can have a variety of textures and potential defects.
Mould-electro-magnetic stirrer (M-EMS) – It is located in the mould, as the name suggest. It carries out the in-mould stirring (sometimes termed as primary electro-magnetic stirrer). A rotary type mould-electro-magnetic stirrer is normally the first choice when selecting billet / bloom stirring equipment. The rotating magnetic field produced gives a circular motion in the liquid steel. The central equiaxed zone is enlarged since the rotational flow promotes the fracturing of the tips of the columnar dendrites, which then serve as nuclei for equiaxed crystal formations in the central zone. Further, the rotational flow flushes the solidification front, hence preventing inclusions and gas bubbles from being entrapped. Still further, the centrifugal force developed results in the lighter phases (i.e. inclusions and gas bubbles moving towards the centre of the strand away from the solidification front. Linear mould-electro-magnetic stirrer is used for larger rectangular strand sections. Two stirrers are then placed horizontally along the cast product wide sides, and the benefits are similar to those obtained with rotary stirring. mould-electro-magnetic stirrer has been traditionally built into the mould in an internal design, where the coil was removed from the caster with the mould. For each mould exchange, electric cables and possibly water hoses were to be connected / disconnected to the coil. New casting machines have external design in which the coil is built around the mould and remains in the casting machine during mould exchange.
Mould facing – It refers to the application of a specially prepared layer of sand, known as facing sand, to the inner surface of a mould cavity. This thin layer is the only part of the mould which comes into direct contact with the hot, molten metal during casting.
Mould flux – It is a synthetic slag, mainly composed of minerals and carbon sources, which is continuously added to the surface of molten steel during the continuous casting process. Its main functions are to act as a lubricant between the solidifying steel and the mould, provide thermal insulation, and absorb impurities from the steel. This helps improve the surface quality of the steel, increase casting efficiency, and extend the life of the mould.
Mould, foundry – It is the form, made of sand, metal, or refractory material, which contains the cavity into which molten metal is poured to produce a casting of desired shape. It is also a die.
Mould geometry – It is the specific shape and configuration of a mould, which is the negative of the final desired product’s shape. It includes the detailed design of the cavity (the female part) and the core (the male part) which, when pressed together, create a void for molten material to fill and solidify into a specific form. This geometry dictates the final product’s shape, size, and other characteristics.
Mould hardener – It is a chemical agent, typically an ester or an acid-cured resin, which reacts with a binder to rapidly solidify the sand mould or core. This process, known as hardening, provides the mould with the strength needed to withstand the pressure of molten metal during casting. The term can also refer to the entire binder system, which includes the binder itself and the hardener, such as the alpha set no-bake system.
Moulding – It is the forming of a polymer or composite into a solid mass of prescribed shape and size by the application of pressure and heat for given times. It is sometimes used to denote the finished part.
Moulding bench – It is a workbench used for making small, lightweight moulds, frequently for non-ferrous metal castings. It is positioned at a height which is convenient for a standing worker and is equipped with tools, patterns, and flasks to support the process of ramming sand into moulds.
Moulding, bench – It is making sand moulds by hand tamping loose or production patterns at a bench without assistance of air or hydraulic action.
Moulding board – It is a smooth, flat wooden board used as a stable base for creating a sand mould. It provides a level surface to support the flask (moulding box) and the pattern as the moulder packs sand around it to form the mould cavity.
Moulding cycle – It is the period of time needed for the complete sequence of operations on a moulding press to produce one set of mouldings. It is also the operations which is necessary to produce a set of mouldings without reference to the total time taken.
Moulding floor – It refers to the ground or floor area where large sand moulds are made manually for medium and heavy castings. This method, called floor moulding, uses the foundry floor as part of the mould, typically without a flask, and is suitable for pieces that are too large for a bench or moulding machine.
Molding, floor – It is the making sand moulds from loose or production patterns of such size that they cannot be satisfactorily handled on a bench or moulding machine, the equipment being located on the floor during the entire operation of making the mould.
Moulding gravel – It is the coarser and more permeable grades of moulding sand normally used in production casting of exceptional size and weight.
Moulding machine – It is a machine for making sand moulds by mechanically compacting sand around a pattern.
Moulding, machine – It is the making of sand moulds from production patterns on moulding machines.
Moulding material – It is a substance used to create moulds for casting, with the most common type being molding sand which is a mixture of sand, clay, and water that holds its shape when moistened or heated. Other materials like plaster, metal, and rubber can also be used depending on the application and desired properties of the final casting.
Moulding, pit – It is a moulding method in which the drag is made in a pit or hole in the floor.
Moulding powder or compound – It consists of plastic material in varying stages of pellets or granulation, and consisting of resin, filler, pigments, reinforcements, plasticizers, and other ingredients, ready for use in the moulding operation.
Moulding press – It is a press used to form powder metallurgy compacts.
Moulding pressure – It is the pressure which is applied to the ram of an injection machine, compression press, or transfer press to force the softened plastic to fill the mould cavities completely.
Moulding process – It is a manufacturing process which shapes a liquid or pliable material by using a rigid frame called a mould. The material is forced into the mould cavity, where it cools and hardens into the final product’s shape. Common examples include injection moulding, compression moulding, and blow moulding, which are used to create a vast range of plastic and rubber products.
Moulding sands – It is the foundry sands containing more than 5 % natural clay, normally between 8 % and 20 %.
Moulding technology – It is a manufacturing process which shapes pliable raw materials, like plastic, metal, or ceramic, using a rigid frame called a mould or matrix. This process is used to mass-produce items by forcing the material into a mould cavity, where it cools and solidifies to take on the final product’s shape. Different methods exist, with common examples including injection moulding and compression moulding.
Mould inserts – These are pre-made components, frequently metal, which are placed inside a mould before plastic is injected to form a single, integrated product. The molten plastic flows around and bonds with the insert, resulting in a finished part which combines the properties of both materials, such as adding strength or a functional element like a threaded screw hole to a plastic part. This process, called insert moulding, is used to create more durable and functional products.
Mould interface – It is the boundary where two separate components in a moulding process come together, such as the point where molten metal meets the mould, or the mechanical connection between the mould and the moulding machine. In manufacturing, the interface can be a critical area for heat transfer, material contact, or mechanical alignment, which influences factors like part quality and processing efficiency.
Mould jacket – It consists of wood or metal form which is slipped over a sand mould for support during pouring of a casting. In case of continuous casting, a mould jacket is a water-cooled housing which surrounds the copper mould tube, providing structural support and thermal management for cooling the molten metal into a solid strand.
Mould layout – For an economical mould layout, the sprue is to be located to minimize the size of the bounding box enclosing the entire casting (including the gating channels), so that a smaller mould is needed. This also applies to multi cavity layout, where the sprue and runner(s) are shared by multiple cavities.
Mould machine – It is also called moulding machine. It is a device which shapes a material into a specific form using a mould, such as an injection moulding machine which injects melted plastic into a mould cavity. It can also refer to a machine in a foundry which uses tools to create sand moulds for casting. The main function is to automate and accelerate the process of creating precise, consistent parts.
Mould oscillation – Mould oscillation is necessary to minimize friction and sticking of the solidifying shell, avoidance of shell tearing, and liquid steel breakouts. Breakouts can cause major damage to equipment and a large machine downtime is needed because of clean up and repairs. Friction between the shell and mould is reduced through the use of mould lubricants such as oils or powdered fluxes. Oscillation is achieved either hydraulically or through motor driven cams or levers which support and reciprocate (or oscillate) the mould. Mould oscillating cycles vary in frequency, stroke, and pattern. However, a common approach is to employ what is called ‘negative strip’, a stroke pattern in which the downward stroke of the cycle enables the mould to move down faster than the section withdrawal speed. This enables compressive stresses to develop in the shell which increase its strength by sealing surface fissures and porosity.
Mould oven – It is a specialized industrial oven used to bake and harden moulds before they receive molten metal. This critical process dries out moisture and strengthens the mould, which prevents defects like gas porosity and ensures a high-quality finished metal casting.
Mould powders – Continuous casting mould 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. The mould powder improves the performance of the casting process and reduces the surface defects. The main functions of the mould powder are (i) to protect liquid steel against oxidation, (ii) to provide lubrication for the solidifying steel, (iii) to control, optimize, and insulate the heat transfer from the liquid steel to the mould and the ambient in horizontal and vertical directions, (iv) to absorb the inclusions from the liquid steel to produce cleaner cast steel product, and (v) to provide chemical protection to the liquid steel from oxidation and other undesired reactions. The high basicity of the mould powder increases its capability to assimilate non-metallic inclusions.
Mould-release agent – It is a lubricant, liquid, or powder (frequently silicone oils and waxes) used to prevent sticking of moulded articles in the cavity.
Mould seam – It is a vertical groove formed at the point of the mould halves. It can also be referred to as a parting line.
Mould shift – It is a casting defect which results when the parts of the mould do not match at the parting line.
Mould shrinkage – It is the immediate shrinkage which a moulded part undergoes when it is removed from a mould and cooled to room temperature. It is also the difference in dimensions, expressed in millimeter per millimeter, between a moulding and the mould cavity in which it has been moulded (at normal-temperature measurement). It is the incremental difference between the dimensions of the moulding and the mould from which it was made, expressed as a percentage of the mould dimensions.
Mould strength – It is the ability of a mould material to maintain its shape and resist deformation under different conditions. It is a critical property in manufacturing, particularly for casting, and is measured under different conditions, such as when the mould is wet (green strength), after it has been dried (dry strength), and at high temperatures (hot strength). A high mould strength is necessary to prevent the mould from collapsing or being eroded by molten metal.
Mould surface – It refers to the outer texture and finish of a mould used in rotational moulding, which is typically achieved through methods like sand or grit blasting to create a matte finish, since highly polished moulds are not suitable for this process. The surface finish affects the adhesion of the powder and the uniformity of the final moulded product. It is also the side of a laminate which faces the mould (tool) during cure in an autoclave or hydroclave.
Mould temperature – It is the surface temperature of the mould cavity, which is important for controlling the cooling and solidification of molten material, especially in injection moulding. Proper and even mould temperature is essential for ensuring the quality, dimensional accuracy, and structural integrity of the final product by preventing defects like warping, shrinkage, and surface imperfections. The ideal temperature varies depending on the specific material being used.
Mould wall – It is a structural component of a building created using specialized formwork to shape concrete. It refers to a structural element for walls, frequently double-curved, made by filling a system of formwork and reinforcement with concrete. Mould wall is also the boundary of a ‘mould’ (a container or die) from which a part is cast. It refers to the physical wall of a mould used in manufacturing to create a part when liquid material inside solidifies and takes the shape of the mould cavity.
Mould wash – It is an aqueous or alcoholic emulsion or suspension of different materials which is used to coat the surface of a casting mould cavity.
Mould weight – It is a heavy object, frequently made of cast iron, which is placed on top of a sand mould before pouring molten metal. The purpose of the weight is to prevent the static pressure of the molten metal from lifting the top half of the mould, called the cope, and causing a defective casting.
Mounted anode – It is a sacrificial anode that is mechanically attached, or mounted, to a structure to provide cathodic protection against corrosion. This is a common installation method for large structures like pipelines and offshore platforms, where the anode is fixed using methods like welding or specialized inserts to withstand forces. Examples of mounting styles include flush-mounted and stand-off, chosen based on factors like drag, space, and the needed current output.
Mounting – It is a means by which a sample for metallographic examination can be held during preparation of a section surface. The sample can be embedded in plastic or secured mechanically in clamps.
Mounting artifact – It is a false structure introduced during the mounting stages of a surface-preparation sequence.
Mounting resin – It consists of thermo-setting or thermo-plastic resins which is used to mount metallographic samples.
Mouse, computer – It is a hand-held pointing device which detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of the pointer (called a cursor) on a display, which allows a smooth control of the graphical user interface of a computer.
Mouse cursor – It is the on-screen visual indicator, like an arrow or blinking line, which shows the position of a user’s input from a pointing device such as a mouse, touchpad, or trackball. It allows users to navigate and interact with a graphical user interface (GUI) by clicking on icons, selecting text, or activating menus and buttons.
Movable stop – It is a feature found in some mechanisms or systems which allows for a point of termination or adjustment to be physically moved or repositioned. It is essentially a stop which can be adjusted to different locations.
Movement factor – It mainly deals with the movement of men and materials. A good layout is to ensure short moves and always tends towards completion of product. It also includes inter-departmental movements and material handling equipment. This includes the flow pattern reduction of unnecessary handling, space for movement, and analysis of handling methods.
Moving average filter – It is a simple digital signal processing technique used to smooth out noise from a time-series signal by calculating a series of averages of a specified number of consecutive data points. It is a type of low-pass filter which averages a sliding window of data, with the oldest value being replaced by the newest as the window moves along. This process helps reduce random fluctuations in the data, making the underlying trend easier to see.
Moving average processes – These are stationary time series which are characterized by a linear relationship between observations and past innovations. The order of the process ‘q’ defines the number of past innovations on which the current observation depends.
Moving bed bioreactor (MBBR) – Moving bed bioreactor process is a fixed film process in which the micro-organisms grow on plastic media. The media are made from high density polyethylene or polypropylene with a diameter of 13 millimeters to 25 millimeters and hence have a large surface area which helps the biomass to grow inside the surface and are in constant motion due to the compressed air which is blown from under the tank. The process has been applied in a variety of industrial wastewater treatment applications in aerobic and anaerobic modes with or without denitrification depending on the mode of mixing.
Moving bed gasifier – It is a type of gasifier where fuel moves down through a fixed bed, supported by a grate, as it undergoes gasification. This ‘plug’ flow is typically counter-current, with an oxidant entering at the bottom and flowing upward as the fuel moves down. Moving bed gasifiers are known for their low mixing and heat transfer, making them well-suited for large coal pieces and certain types of bio-mass but less effective for fine particles or caking coals.
Moving bed heat exchanger – It is a device which transfers heat between a fluid and a flowing bed of granular solid particles, frequently using gravity to move the particles. It is an indirect heat exchanger where a working fluid flows through tubes or plates, while the granular solids move in contact with these surfaces to either absorb heat from the fluid or give heat to it. Moving bed heat exchangers are known for their efficiency, robustness, and application in high-temperature systems like concentrated solar power plants and waste heat recovery.
Moving blade – It is a component which rotates and generates power from a fluid flow, such as the blades on a turbine. It is contrasted with a ‘fixed blade,’ which is stationary and used to redirect the fluid flow onto the next set of moving blades. Moving blades are subject to high stress from rotation, vibration, and temperature, which can cause wear and deformation over time.
Moving coil – It is an analog measuring instrument which uses the interaction between a coil and a magnetic field to measure electrical current or voltage. When a current flows through a coil suspended in a permanent magnetic field, the resulting torque causes the coil to rotate, moving a pointer along a calibrated scale to indicate the measurement. These devices, frequently called PMMC (permanent magnet moving coil) instruments, are highly accurate but only work for direct current (DC).
Moving range (MR) – It is the difference between the two consecutive individual values used as ‘range’ when number of items in a group is one.
Moving substrate – It is a component in wastewater treatment systems, such as ‘moving bed bio-film reactors (MBBRs), where bio-film develops on a substrate which is in motion, typically made of plastic wheels, allowing for improved treatment efficiency compared to stationary systems.
MPH – It means miles per hour (a unit of speed). It is used for vehicle speed on a speedometer.
MRI – It is magnetic resonance imaging. It a technique for examining the interiors of using sensitive measurements of the magnetic fields of atomic nuclei.
M-section – It consists of light weight beams which are mainly used in the construction of pre-engineered housing. These beams are produced in lighter weights, normally 10 kilograms per metre to 15 kilograms per metre.
M-shell – It is the third layer of electrons surrounding the nucleus of an atom, having electrons characterized by the principal quantum number 3.
MSME – It means micro, small, and medium enterprises. These are defined based on investment in plant / machinery or equipment and annual turnover
‘Ms’ temperature – For any alloy system, it is the temperature at which martensite starts to form on cooling.
MTBF – It is ‘Mean Time between Failures’. It is a measure of reliability which represents the average time a system or component is expected to operate before experiencing a failure. It is a crucial metric for assessing the dependability of repairable systems and is calculated by dividing the total operating time by the number of failures within that time. A higher MTBF indicates a more reliable system, meaning it is expected to operate for a longer period before needing repair.
MTTF – It is ‘Mean Time to Failure’. It is a reliability metric which represents the average time a non-repairable system or component operates before experiencing a failure. It essentially indicates the expected lifespan of a product that is replaced rather than repaired after failure. A higher MTTF signifies a more reliable product with a longer operational lifespan.
MTTR – It is ‘Mean Time to Restore (or Repair)’. It is a metric which measures the average time it takes to fix a malfunctioning system or piece of equipment and return it to full operational status. It essentially represents how quickly a system can be brought back online after a failure.
Muck – It is the ore or rock which has been broken by blasting.
Muck sample – It is a representative piece of ore which is taken from a muck pile and then assayed to determine the grade of the pile.
Mud – It is a term frequently used to designate plastic lining materials.
Mud cracks – These are microscale fractographic artifacts created when a liquid dries on the fracture surface. These cracks are frequently associated with (i) incomplete removal of a cleaning agent from a fracture surface prior to examination in the scanning electron microscope, or (ii) dried solutions created from stress-corrosion cracking conditions.
Mud daubing – It is the act of coating or smearing a surface with a thick, sticky substance like mud.
Mud drum – It is a component of a water-tube boiler, typically located at the bottom, which serves as a collection point for impurities and sediment in the boiler water. It is designed to trap ‘mud’ (impurities) which settles out of the water, preventing it from circulating and potentially causing damage to the boiler.
Mud gun – It is equipment installed near taphole in the cast house for pushing taphole mass under pressure in the taphole for the purpose of closing it. Mud gun performs one of the most important and critical operations of the tap hole. Closing a blast furnace tap hole under any condition is a key safety requirement.
Mud gun filling machine – These machines are used for the automatic filling of the mud gun.
Mud lining – It is a protective barrier or layer made of soil, frequently mixed with water or other binders, to provide containment or protection in civil engineering, oil drilling, and construction. The specific composition and application of ‘mud lining’ can vary considerably depending on the industry. In civil and environmental engineering, mud lining is a barrier for preventing the leakage of fluids, such as in landfills, waste lagoons, and water reservoirs.
Mud-stone – It is a type of sedimentary rock formed from the accumulation of silt and clay-sized particles, typically resulting in a fine-grained texture.
Muff coupling examination – It is a flexible coupling which is used to connect shafts in equipments systems, needing routine checks for wear, alignment, and secure attachment.
Muffle furnace – It is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash. After the development of high-temperature heating elements, new muffle furnaces quickly moved to electric designs. Today, a muffle furnace is often a front-loading box-type oven or kiln for high-temperature applications such as fusing glass, creating enamel coatings, ceramics and soldering and brazing articles. They are also used in testing laboratories to determine what proportion of a sample is non-combustible and non-volatile (i.e., ash).
Muliductor power source – It is a device used in foundry and casting operations to convert standard three-phase, 60-cycle electrical current into a single-phase, medium-frequency (180-cycle) current. This conversion is specifically engineered to power an induction furnace, where it produces a strong and controlled stirring action for melting metal. The stirring effect helps create a more uniform melt and temperature distribution.
Muller – It is a machine used to mix and temper sand with additives like clay and water to create a consistent, mouldable mixture for metal casting. It uses a combination of heavy rollers which crush and knead the sand and plows which lift and fold it, ensuring the additives are uniformly distributed across the sand grains. This mechanical process replaces manual mixing, increasing efficiency and consistency for making strong casting moulds.
Muller-Lyer illusion – It is an optical illusion consisting of three stylized arrows. When viewers are asked to place a mark on the figure at the midpoint, they tend to place it more towards the ‘tail’ end. Muller-Lyer illusion shows the difference between perception and reality. In case of visual inspection, the difference of perception between two inspectors depends upon training and experience and the mental and physical state of the observers at the time the observation is made. Perception can be affected by fatigue and health. Fatigue reduces the efficiency and visual ability of the observer. These problems lead to inaccurate interpretation of physical data. An ideal inspection is the one in which all of the factors namely training, experience, lighting, and environmental conditions are optimized.
Mullen test – It consists of measurement of bursting strength of foil in kilograms force per square centimeter. Testing machine applies increasing pressure to 645 square millimeters of the sample until it ruptures. In a conveyor system, Mullins effect is a particular aspect of the mechanical response in filled rubbers in which the stress-strain curve depends on the maximum load encountered. The phenomenon can be idealized as an instantaneous and irreversible softening of the stress-strain curve that occurs whenever the load increases beyond its prior all-time maximum value. At times, when the load is less than a prior maximum, nonlinear elastic behaviour prevails.
Mulling – It is the mixing and kneading of foundry moulding sand with moisture and clay to develop suitable properties for moulding. It is the intensive mixing process used to homogenize and activate the bonding agents in moulding sand. A special machine called a sand muller combines sand, clay (typically bentonite), and water to create a cohesive and pliable mixture for making casting moulds.
Mulling and tempering – It is the thorough mixing of sand with a binder, either natural or added, with lubricant of other fluid, as water.
Mullite – It is a rare silicate mineral formed during contact metamorphism of clay minerals. It can form two stoichiometric forms: 3Al2O3.2SiO2 or 2Al2O3.SiO2. Unusually, mullite has no charge-balancing cations present. As a result, there are three different aluminium sites namely two distorted tetrahedral and one octahedral. Mullite is present in the form of needles in porcelain. It is produced during different melting and firing processes, and is used as a refractory material, because of its high melting point of 1,840 deg C. Mullite morphology is important for its application. There are two common morphologies for mullite. One is a platelet shape with low aspect ratio and the second is a needle shape with high aspect ratio. If the needle shape mullite can form in a ceramic body during sintering, it has an effect on both the mechanical and physical properties by increasing the mechanical strength and thermal shock resistance. The most important condition relates to ceramic chemical composition. If the silica and alumina ratio with low basic materials such as sodium and calcium is adjusted, the needle shape mullite forms at around 1,400 deg C and the needles interlocks. This mechanical interlocking contributes to the high mechanical strength of porcelain.
Mullite refractories – Mullite refractories are manufactured from fused and sintered mullite grains and also with mullite forming natural minerals like sillimanite and andalusite.
Mullite refractory castable – It is mainly composed of mullite, whose components are Al2O3 and SiO2. The melting point of mullite is 1,910 deg C so that it has good refractoriness. This product presents the characteristics of low thermal expansion, good wear resistance, and good thermal resistance.
Multi-agent system – It refers to a system where multiple individual, autonomous agents work together, communicate, and coordinate to achieve individual or collective goals. Unlike a single-agent system, which acts alone, a multi-agent system uses cooperation and interaction to solve complex problems more efficiently, adapt to dynamic environments, and scale up by adding more agents.
Multi-axial – It refers to a condition or loading where stresses or forces act along more than one axis simultaneously. This creates a complex state of stress in a material, unlike uniaxial conditions where stress is applied in only one direction. Multi-axial stress is important in analyzing the fatigue, failure, and damage of components under real-world conditions, which rarely involve forces along a single axis.
Multi-axial fatigue – It is a general term which can be used to describe loading and / or loading plus geometry conditions resulting in complex states of stresses and strains, either locally or globally. More specifically, multiaxial loading results in a state of stress and / or strain, which manifests as two or more components in the stress or strain tensor.
Multi-axial loading – It is the application of forces or stresses in more than one direction simultaneously on a material or structure. This contrasts with uniaxial loading, which involves forces in a single direction. Examples include a shaft under combined bending and torsional loads, or a component experiencing stresses from multiple sources like welding, thermal gradients, and boundary conditions.
Multi-axial stresses – It is a stress state in which two or three principal stresses are not zero.
Multi-block approach – It is a methodology for analyzing complex systems by partitioning variables into meaningful groups or ‘blocks’ to find relationships between them. It is used in different fields like data analysis, chemical engineering, and computational fluid dynamics to simplify complex problems, find associations between different data sources, and improve efficiency or computation. Key applications include analyzing complex datasets like sensory and instrumental measurements, monitoring large-scale processes, and improving computational efficiency for problems like fluid flow simulation.
Multibody system – It is the study of the dynamic behaviour of inter-connected rigid or flexible bodies, each of which can undergo large translational and rotational displacements.
Multi-circuit winding – In filament winding, a winding which needs more than one circuit before the band repeats by laying adjacent to the first band.
Multi-channel analyzer (MCA) – It is an instrument which splits an input signal into a number of channels with respect to a particular parameter of the input.
Multi-chip module (MCM) – It is generically an electronic assembly (such as a package with a number of conductor terminals or ‘pins’) where multiple integrated circuits (ICs or ‘chips’), semi-conductor dies and / or other discrete components are integrated, normally onto a unifying substrate, so that in use it can be treated as if it is a larger integrated circuit. Other terms for multi-chip module packaging include heterogeneous integration or hybrid integrated circuit. The advantage of using multi-chip module packaging is that it allows a manufacturer to use multiple components for modularity and / or to improve yields over a conventional monolithic integrated circuit approach.
Multi-collinearity – It is the situation in a regression model in which two are more predictors are highly correlated with each other, leading to poor-quality coefficient estimates. Multi-collinearity is a term used to describe when two variables are correlated with each other. In statistical models, multi-collinearity causes problems with the efficiency of parameter estimates. It also raises some philosophical issues, since it becomes difficult to determine which variables (both, either, or none), are causal and which are the result of illusory correlation.
Multi-component system – It is a system consisting of two or more distinct components, which can be chemical substances, parts of a larger whole, or even different types of particles. The specific definition depends on the field of study, but it normally refers to a mixture or combination where the behaviour and properties are influenced by all of the individual parts.
Multi-criteria decision-making – It is the process of selecting the best option from multiple alternatives when faced with multiple, frequently conflicting criteria, such as cost, quality, and performance. It provides a structured and quantitative approach to complex decisions by using methods to evaluate alternatives against criteria and assigning weights to reflect their importance, ultimately helping people to make rational and justified choices.
Multi-crystalline silicon – It is a semiconductor material composed of several small silicon crystals with different orientations, created by solidifying molten silicon into a large, square ingot. It is mainly used to manufacture less expensive poly-crystalline solar cells and is known for being more affordable than mono-crystalline silicon but slightly less efficient.
Multi-crystalline silicon cell – It is a solar cell made from a block of silicon which contains several small, individual crystals of different orientations. These cells are produced by melting silicon, then allowing it to cool and solidify into a large, cubic ingot, a process called directional solidification. Multi-crystalline silicon cells are a cost-effective alternative to mono-crystalline silicon cells, though they normally have lower efficiency.
Multi-crystalline wafer -It is a thin slice of silicon composed of multiple, randomly oriented crystal grains, unlike a single-crystal wafer. These wafers are made by casting molten silicon into ingots, which are then cut into wafers. While this process makes multi-crystalline wafers cheaper to produce and frequently square or rectangular for better packing, it results in grain boundaries which slightly decrease solar cell efficiency compared to their mono-crystalline counterparts.
Multics – It is an influential early time-sharing computer operating system, first released in 1969.
Multi-disciplinary design optimization – It is a field of engineering which uses optimization methods for solving the design problems incorporating a number of disciplines. Multi-disciplinary design optimization allows designers to incorporate all relevant disciplines simultaneously. The optimum of the simultaneous problem is superior to the design found by optimizing each discipline sequentially, since it can exploit the interactions between the disciplines. However, including all disciplines simultaneously significantly increases the complexity of the problem.
Multi-disciplinary team (MDT) – This team consists of a group of professionals from different fields who work together to achieve a common goal. These teams bring together diverse expertise to address complex issues, and develop comprehensive solutions, The team consists of individuals with varying professional backgrounds and skill sets. Despite the different backgrounds, the team members unite around a common objective or project.
Multi-effect distillation – It is an industrial process which uses multiple stages, or ‘effects’, to efficiently desalinate seawater or purify other liquids by evaporation and condensation. In each effect, the heat from the condensation of vapour in one stage is used to evaporate water in the next, which operates at a lower pressure and temperature. This system maximizes energy reuse and can be powered by low-pressure steam, waste heat, or electricity.
Multi-effect evaporation – It is a process which uses multiple stages, or ‘effects’, to efficiently concentrate a solution by evaporating a solvent, normally water. Each effect operates at a lower pressure and temperature than the last, using the vapour from the previous effect as the heat source for the next, which considerably reduces energy consumption compared to single-effect evaporation.
Multi-effect evaporator – It is an industrial equipment which uses a series of stages (effects) to efficiently evaporate a solvent, very frequently water, from a solution. In this system, the vapour produced in the first effect (at the highest pressure) is used as the heating source for the next effect, which operates at a lower pressure and temperature. This design maximizes energy efficiency, as only the first effect needs an external heat source like steam.
Multi-filament yarn – It consists of a large number (500 to 2000) of fine, continuous filaments (frequently 5 to 100 individual filaments), normally with some twist in the yarn to facilitate handling.
Multi-fuel burner – It is a burner by means of which more than one fuel can be burned.
Multi-functional reactor – It is a single unit which performs both a chemical reaction and at least one other operation, such as separation, heat exchange, or mass transfer. This integration offers benefits like increased efficiency, higher conversion, compactness, and energy savings by combining functions which otherwise needs separate equipment. Examples include reactive distillation and membrane reactors.
Multi-generation energy system – It is an integrated system which uses a single primary energy source to simultaneously produce multiple forms of useful energy, such as electricity, heating, and cooling, along with other products like fresh-water or hydrogen. The goal is to improve overall energy efficiency by reducing wasted energy compared to using separate, conventional systems for each output. These systems can combine different technologies to create more sustainable and resource-efficient solutions.
Multi-grade oil – It is an oil having relatively little change in viscosity over a specified temperature range.
Multi hearth furnaces – These furnaces are a variation of the rotary hearth furnace with several levels of round stationary hearths with rotating rabble arms which gradually plow granular or small lump materials radially across the hearths, causing them to eventually drop through ports to the next level.
Multi-hole die – It is an extrusion die, with more than one hole, allowing multiple extrusions to be made simultaneously from one billet.
Multi-hole injector – It is a fuel injector with multiple small nozzles which spray fuel, typically ranging from 4 holes to 12 holes, into an engine’s combustion chamber. This design improves fuel atomization, leading to more efficient combustion, better fuel economy, and reduced emissions compared to single-hole injectors. These injectors are normally used in both diesel and gasoline direct injection (GDI) engines and operate under high pressure to achieve superior spray dispersion and mixing with air.
Multi-input multi-output (MIMO) – It refers to systems with multiple inputs and multiple outputs, contrasting with simpler single-input, single-output systems. It is normally used in wireless communications to increase data rates and reliability by using multiple antennas at both the transmitter and receiver to send and receive multiple data streams simultaneously. Beyond communications, multi-input multi-output concepts apply to areas like control systems, where multiple variables are manipulated to control multiple outputs, and mechanical systems, such as structural testing with multiple shakers and sensors.
Multi-input single-output (MISO) system – It is a control or communication system which uses multiple input signals to produce a single output. It is a control system which utilizes multiple input signals to manage a single output, frequently applied in power system models to improve controller design and performance under different operating conditions. A key application is split-range control, where different inputs (manipulated variables) are used to control a single output (controlled variable) to extend its operating range.
Multi-layer 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.
Multi-layer film – It is a composite material made of multiple distinct layers of different materials, stacked and bonded together to achieve superior properties not available in a single material. These films are created through processes like coextrusion or lamination and are used in a wide range of applications, including optics for manipulating light, and electronics for components like dielectric layers or lithographic masks. The engineering focus is on controlling the film’s mechanical, optical, and chemical properties by carefully selecting and arranging the individual layers.
Multi-level conveyor structure – It is a conveyor system with multiple tiers or levels, necessitating frequent inspections for stability, alignment, and material flow on each level.
Multi-loop controller – It is a control system which uses multiple feedback loops to simultaneously regulate different variables or processes within a single system. This architecture, frequently involving an inner and an outer loop, improves stability and performance by allowing independent control of each loop while coordinating overall system coherence. These controllers are used for complex applications, such as controlling temperature and pressure in a machine simultaneously.
Multi-meter – It is a test instrument that can measure current, voltage, or resistance (though not concurrently).
Multinomial logistic regression – It is a logistic regression model for a study end point with more than two values.
Multi-mode analysis – It is a method which studies the interaction of multiple vibration modes within a structure or analyzes a process with multiple operational states. It is used to evaluate how a structure responds to forces by considering its multiple natural frequencies and amplitudes simultaneously. In process engineering, it involves analyzing systems which can switch between different steady-state modes, such as a production line which transitions between different batch processes or continuous states.
Multi-objective model – It is an optimization approach which measures the trade-off between multiple conflicting or non-conflicting objectives, allowing decision-makers to identify Pareto-optimal solutions within a given context.
Multi-objective optimization – It is the process of finding the best solution to a problem with two or more, frequently conflicting, goals which are to be optimized simultaneously. Instead of a single ‘best’ answer, multi-objective optimization produces a set of solutions called the Pareto optimal set, where improving one objective can cause another to worsen. This approach helps engineers make trade-offs in complex designs, such as balancing a product’s performance with its cost and environmental impact.
Multi-objective optimization methods – These refer to techniques used to find the best possible solution to problems which involve multiple objectives, such as maximizing profits or minimizing costs and resource usage in different fields of study.
Multi-pass equal-channel angular extrusion – It is a severe plastic deformation (SPD) process where a workpiece is repeatedly forced through a die with two intersecting channels of equal cross-section. This process induces large shear strains, considerably refining the material’s grain structure without altering its overall dimensions. Each pass through the die, or ‘multi-pass’, involves rotating the workpiece (or not, depending on the processing route) before reinserting it for the next pass, further improving grain refinement.
Multi-pass equal-channel angular processing – It is a severe plastic deformation technique used to refine the grain structure of metallic materials. It involves repeatedly pressing a billet through a die with intersecting channels, subjecting the material to intense shear deformation without considerable changes to its cross-sectional dimensions. Multiple passes, with or without changes in the billet’s orientation between passes, are used to achieve larger accumulated strains and further refine the microstructure.
Multi-pass weld – It is a technique where multiple layers of weld metal are deposited one on top of another to fill a joint, which is necessary for welding thick materials. This method creates a stronger, larger weld compared to a single-pass weld and is used for joining thick sections, repairs, or build-ups. Each pass is a single layer of weld bead, with one pass often allowed to cool before the next is applied.
Multi-path effect – It is the phenomenon where a signal, such as a radio wave, arrives at a receiver through multiple paths, caused by reflection, diffraction, and scattering off objects like buildings or mountains. This results in the signal being received multiple times, with each copy having travelled a different distance, leading to phase and amplitude variations which can cause interference, signal fading, and inaccuracies in positioning or data transmission.
Multi-path propagation – It is the phenomenon where a radio signal reaches a receiver by travelling along two or more different paths, frequently because of reflection, diffraction, or refraction from objects like buildings or terrain. This causes the received signal to be a composite of multiple time-delayed, phase-shifted versions of the original, which can lead to signal distortion and interference known as multi-path fading.
Multi-path routing – It is a technique which uses multiple alternate paths to send data between two points in a network, instead of a single path. It improves network performance and reliability by enabling load balancing across different links, providing redundancy to mitigate failures, and potentially increasing overall bandwidth. This approach involves discovering, distributing traffic, and maintaining multiple routes from source to destination.
Multi-phase flow – It is a flow formed by a mixture of two or more distinct phases.
Multi-phase fluid dynamics – It is the study of the simultaneous flow of fluids in two or more different phases, such as gas, liquid, and solid. This field analyzes the complex interactions between these phases to design, optimize, and safely operate systems in several industries, including chemical, oil and gas, and mechanical engineering.
Multi-phase jet solidification (MJS) – It is a rapid prototyping process which involves extruding a heated powder-binder mixture through a nozzle to build parts layer by layer. The derivation of multi-phase jet solidification involves understanding the interplay of heat transfer, fluid dynamics, and material properties during the solidification process. This includes modeling the flow of the multiphase mixture, the heat transfer to cause solidification, and the evolution of the microstructure as the material transitions from liquid to solid.
Multi-phase mixture – It is a combination of two or more distinct, non-molecularly mixed phases (like a gas, liquid, or solid) flowing together. Examples include a gas-liquid flow with bubbles in a liquid, or a liquid-solid flow with particles suspended in a fluid. Engineering challenges involve modeling the complex interactions and transport phenomena within these mixtures, which are common in industrial and natural systems.
Multi-phase reactor – It is a vessel where chemical reactions occur involving two or more distinct phases, such as gas, liquid, or solid. These reactors are designed to handle complex interactions where mass and heat transfer between phases, like gas-liquid, gas-solid, liquid-solid, or gas-liquid-solid systems, are critical to the reaction’s outcome.
Multi-phase steel – It is a type of advanced high-strength steel (AHSS) characterized by a microstructure consisting of multiple phases, such as ferrite, martensite, bainite, and retained austenite, in considerable proportions. These phases are carefully engineered to achieve a balance of high strength and ductility, making them suitable for different demanding applications, particularly in the automotive industry for light-weighting and improved safety.
Multi-phase system – It is a system which contains two or more distinct phases of matter, such as solid, liquid, or gas, which can coexist and interact. These systems are critical in several industries, like oil and gas and chemical processing and are studied to understand complex phenomena like multi-phase flow, which is the simultaneous movement of these different phases.
Multi-photon absorption – It is a nonlinear process where a material simultaneously absorbs two or more photons to transition from a lower to a higher energy state. This is important in applications like three-dimensional (3D) microfabrication, where it enables high-resolution 3D printing (multi-photon lithography) and two-photon microscopy. It is particularly useful when the energy of a single photon is too low to cause excitation, as the combined energy of multiple photons can overcome this barrier.
Multi-photon ionization – It is the process where an atom or molecule absorbs two or more photons simultaneously, with their combined energy exceeding the ionization energy, causing an electron to be ejected and the molecule to become ionized. This phenomenon is enabled by high-intensity light sources, particularly lasers, and is a fundamental process in high-energy laser-matter interactions, plasma formation, and advanced spectroscopy techniques.
Multi-photon lithography – It is a 3D printing technique which uses a focused, high-intensity laser to selectively cross-link or polymerize a photo-sensitive resin. This process relies on multi-photon absorption, where a molecule absorbs two or more photons at once, which only occurs at the high peak intensity in the laser’s focal point (the ‘voxel’). By scanning this voxel, engineers can create intricate 3D structures with feature sizes down to the sub-micrometer scale for applications in optics and micro-machines.
Multiple – It is a piece of stock for forging which is cut from bar or billet lengths to provide the exact quantity of material for a single work-piece.
Multiple analysis of variance (MANOVA) – As the extension of ANOVA (analysis of variance) tool, the comparison can be gained across two or more outcome variables. Here the groups are the equivalent of a categorical predictor variable.
Multiple-cavity die – It is a foundry tool with more than one identical cavity, allowing for the casting of multiple identical parts in a single injection cycle. This process is used for high-volume production of small to medium-sized, identical components to increase efficiency and lower the cost per part.
Multiple-comparison procedure – It is a statistical procedure for comparing group means which avoids capitalization on chance.
Multiple constraints – It refers to the challenge of balancing several limiting factors, such as technical, economic, environmental, and social, to achieve a project’s objectives. It can also specifically mean applying multiple mathematical equations simultaneously to define relationships between design elements, such as in multipoint constraints (MPC) used in CAD (computer aided design) and structural analysis. The core challenge is to find a design that meets all requirements, which frequently needs trade-off analysis and optimization.
Multiple criteria – It refers to the principles or standards by which multiple aspects of a decision can be judged or decided, reflecting the values and levels of expertise of the participants involved in the decision-making process.
Multiple-die pressing – it is the simultaneous compaction of powder into several identical parts with a press tool consisting of a number of components.
Multiple effect distillation – It is a desalination method which utilizes heat and electricity to produce potable water through a series of chambers where seawater is evaporated and condensed using hot steam. This process involves multiple stages of evaporation and condensation to efficiently extract water from seawater.
Multiple emulsion – It is a complex dispersion where droplets of one emulsion are suspended inside droplets of another, such as a water-in-oil-in-water (W/O/W) or oil-in-water-in-oil (O/W/O) system.
Multiple etching – It is the sequential etching of a micro-section, with specific reagents attacking distinct micro-constituents.
Multiple feasibility – It refers to the comprehensive assessment of a proposed project across several distinct dimensions to determine its overall practicality and likelihood of success before committing substantial resources. This process ensures the project is sound from several perspectives, not just one.
Multiple frequency – It refers to a system or technique which operates or analyzes data using more than one frequency at a time, such as transmitting multiple signals simultaneously over a single channel (frequency-division multiplexing) or using different frequencies for improved cleaning or testing. It can also describe a system which resonates at several frequencies at once or a technique where signals are analyzed at different frequencies for a more complete understanding.
Multiple hearth furnaces – Multiple hearth furnaces used to be in a dominant position as a roasting furnace for sulphide ores (mainly pyrites in sulphuric acid production). It has now been almost completely replaced by fluidized-bed roasting equipment since the 1960s. A multiple hearth furnace consists of an internally lined steel cylinder with a number of horizontally mounted, lined platforms called hearths. The circular hearths are thinner near the centre, which has an opening for a vertical shaft. An adjustable-speed drive with overload protection turns the shaft at 0.2 revolutions per minute to 5 revolutions per minute. From 1 to 4 rabble arms per hearth are latched to the shaft in a gastight manner. These arms bear oblique stirring teeth to move the solids over the hearth. On one hearth, the motion is from centre to edge, on the next from edge to centre depending on the inclination of the stirring teeth. The openings in the hearths, through which the charge travels from the top of the furnace to the bottom, hence alternate from central to peripheral.
Multiple impeller system – It is a configuration with two or more impellers mounted on a single shaft within a vessel to improve mixing and fluid transfer. These systems are normally used in tall vessels for applications like gas-liquid reactions, where they can improve gas-liquid mass transfer, gas utilization, and heat transfer compared to a single impeller.
Multiple imputation – It is a means of filling in missing data which involves using the inter-relationships among variables in one’s analysis, along with random error, to estimate the missing values. This process is repeated to create multiple copies of one’s data; then one’s statistical analysis of the data is repeated with each copy of the dataset and the results are combined into one final set of results.
Multiple-input multiple-output – It is a wireless communication technology which uses multiple antennas at both the transmitting and receiving ends to boost data rates and signal reliability. It enables the simultaneous transmission and reception of multiple data streams over the same radio channel, which increases network capacity and performance.
Multiple-layer alloy plating – It is a technology for engineering desirable properties into thin surface layers through the use of carefully controlled deposit micro-structures. As implied by the name, multiple-layer alloy electro-deposition involves the formation of an inhomogeneous alloy consisting of lamellae of different composition. In case of a binary alloy composed of species A and B, each lamella of species A (or species B) in the film has a nearly uniform thickness tA (or tB). The modulation wave-length (t = tA + tB) characterizes the imposed compositional micro-structure and typically takes a value anywhere from angstroms to micrometers in thickness. Multiple-layer thin films with spatially periodic compositional microstructures of the type in case of a binary alloy are sometimes referred to as composition-modulated alloys (CMAs) or as superlattice alloys.
Multiple linear regression – It is a linear regression involving two or more independent variables. Simple linear regression, which is merely used to illustrate the basic properties of regression models, contains one explanatory variable and is rarely if ever used in practice.
Multiple loading conditions – These refer to the different scenarios where a structure or component is subjected to different types and combinations of loads at different times, as opposed to all loads acting simultaneously. This concept is critical for designing structures which can withstand a range of potential stressors, from static forces like dead loads to dynamic and environmental forces like wind or seismic events. By analyzing these different load combinations, engineers can create safer and more robust designs that account for worst-case scenarios.
Multiple material phase – It is a system or structure composed of two or more distinct materials or distinct physical states of the same material, each with its own chemical composition and mechanical properties. These phases are integrated to achieve improved performance characteristics which a single material cannot provide, such as improved structural strength, better rate capability, or energy efficiency. Examples include composite materials (like fibre-reinforced plastics), metal alloys with different microstructures, and systems using multiple phase change materials.
Multiple mould – It is composite mould made up of stacked sections. Each section produces a complete gate of castings. All castings are poured from a central down-gate. It also frequently refers to a multi-cavity mould, which contains multiple impressions for a single part, allowing for the production of several items in one casting cycle.
Multiple-pass weld – It is a weld made by depositing filler metal with two or more successive passes.
Multiple-ply belt – Multiple-ply belt is normally made up of two or more plies, or layers, of woven cotton, rayon, or a combination of these fabrics, bonded together by an elastomer compound. Belt strength and load support characteristics vary according to the number of plies and the fabric used. The multiple-ply conveyor belt was the most widely used belt through the mid-1960s, but today it has been replaced by reduced-ply belt.
Multiple punch press – It is a mechanical or hydraulic press which actuates several punches individually and independently of each other.
Multiple scattering event – It is a collision process which can be described as a sequence of binary scattering events that may or may not be elastic.
Multiple sensor system – It is a system which collects data from multiple sensors simultaneously to create a more complete and accurate understanding of an environment or object. This integration, known as multi-sensor fusion, uses data from different sensor types (like optical, radar, lidar, or pressure) to improve performance, improve accuracy, and handle complex situations where a single sensor is insufficient.
Multiple shear bands – These refer to the formation of several distinct zones of highly localized deformation within a material, occurring when a single shear band cannot adequately dissipate the applied energy. This phenomenon is frequently observed under conditions of high strain rates or in materials with limited homogeneous deformation modes, such as in metallic glasses under compression or rolling. The development of multiple shear bands can be influenced by factors like material composition, sample geometry, and the specific loading mode.
Multiple-slide machine – It is also called a four-way, or four-slide machine. It is a somewhat specialized item of stamping equipment, although it is very versatile within a limited area of stamping applications. It is a type of specialized metalworking equipment used for high-volume production of small stamped components from coil or wire stock. These machines utilize a system of cam-controlled tools operating at right angles to each other, allowing for complex shapes and bends to be formed in a single operation. They are particularly well-suited for producing parts like brackets, clips, electrical connectors, and clamps.
Multiple-slide press – It is a press with individual slides, built into the main slide or connected to individual eccentrics on the main shaft, which can be adjusted to vary the length of stroke and the timing.
Multiple spot welding – It is the spot welding in which several spots are made during one complete cycle of the welding machine.
Multiple steady states – These refer to a system which can have more than one stable operating condition for the same set of input parameters, where the rate of change of all state variables is zero. This phenomenon is frequently seen in chemical reactors because of the nonlinear relationships in mass and energy balance equations, where different initial conditions or small disturbances can lead the system to settle into different stable outputs, such as varying temperatures or concentrations.
Multiple strand conveyor chain – It is a conveyor chain with multiple parallel strands, needing regular assessments for wear, tension, and overall integrity.
Multiple stress creep recovery test – It is a test which is used to evaluate the high-temperature performance of asphalt binders by measuring their resistance to permanent deformation (rutting). It assesses this by subjecting a binder to repeated cycles of loading and recovery at two different stress levels and measuring the resulting strain and recovery to determine the non-recoverable creep compliance and percent recovery. These values help classify binders based on their expected traffic loads and service temperatures.
Multiple use – It normally refers to the management and utilization of a resource, like land or a building, for more than one purpose or function.
Multiplier phototube – It is a device in which incident electro-magnetic radiation creates electrons by the photo-electric effect. These electrons are accelerated by a series of electrodes called dynodes, with secondary emission adding electrons to the stream at each dynode.
Multiplexing – It is a technique for measuring multiple signals using a single analog-to-digital converter (ADC), where a multiplexer selects one input channel at a time and routes the signal for digitizing, resulting in a reduced effective sampling rate per channel proportional to the number of channels.
Multiplying factor – It means the number by which a data unit is multiplied to get the data in another unit. It is normally used for the conversion of units.
Multipoint constraint – It is an engineering concept in finite element analysis which links multiple nodes to a single equation, forcing them to move together as per a specific relationship. Unlike single-point constraints which fix a node’s movement, multipoint constraint connect a group of nodes to enforce more complex boundary conditions, such as simulating a symmetry plane or ensuring mesh compatibility between different parts of a model.
Multipoint transmission – It is a communication method where one source transmits data to multiple receivers, enabling one-to-many or many-to-many communication. It can involve a single central hub connecting to multiple remote sites (point-to-multipoint) or multiple devices sharing a single link to communicate with each other. A related technology, ‘coordinated multipoint’ (CoMP), involves multiple transmission points cooperating to improve signal quality for users.
Multipollutant control – It is the process of managing or removing multiple air pollutants simultaneously, frequently using a single system or integrated strategy, rather than addressing them one at a time. This approach is more efficient for sources which emit several pollutants, such as coal-fired power plants, and can lead to greater overall health and economic benefits compared to single-pollutant strategies. Examples of pollutants addressed include sulphur di-oxide (SO2), nitrogen oxides (NOx), particulate matter, and mercury.
Multi-port burner – It is a burner having a number of nozzles from which fuel and air are discharged.
Multi-port nozzle, plasma arc welding and cutting – It is a constricting nozzle containing two or more orifices located in a configuration to achieve a degree of control over the arc shape.
Multi-roll mills – These rolling mills consist of six, seven, twelve or twenty horizontally mounted rolls. In all these mills 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 mills are used for rolling of very thin sheets, strips and foils.
Multi-resolution analysis – It is a mathematical framework which decomposes a signal into a hierarchy of different resolution levels, separating it into approximation and detail components to allow for analysis of both low-frequency and high-frequency features. It uses a series of nested subspaces, scaling functions, and wavelets to systematically construct a signal’s representation at different scales. This process is foundational for techniques like the wavelet transform and is used in fields such as signal processing and image analysis for feature extraction and data representation.
Multi-scale approach – It is a strategy which analyzes phenomena by examining multiple levels of detail simultaneously, from the smallest components (like atoms or electrons) to the largest structures or systems. It is used to understand complex systems by connecting different scales of space and time, enabling more accurate prediction and design of materials and systems like composite materials and process systems. This method can be used in different ways, such as a ‘bottom-up. approach where micro-scale data is used to inform macro-scale models, or by using concurrent methods.
Multi-scale effects – It refer to the influence of multiple hierarchical levels in a material’s structure on its mechanical properties, particularly in improving fracture toughness and defect tolerance, as observed in silica. This concept highlights how variations at different scales can improve a material’s ductility and strength through mechanisms such as stress distribution and crack arrest.
Multi-scale image decomposition – It is a technique which represents an image as a combination of its components at different levels of resolution or ‘scales’. It separates an image into different layers, such as a smooth, low-frequency ‘cartoon’ component and a high-frequency ‘texture’ component, or a detailed layer and a background layer. This allows for more effective image analysis, manipulation, and processing by isolating features of different sizes.
Multi-scale modelling – It is a computational approach which uses multiple models at different scales to represent a system, combining micro-scale detail with macro-scale behaviour to achieve accuracy without sacrificing efficiency. This method is used in several fields to simulate complex phenomena by integrating information from different levels of resolution, such as combining molecular dynamics with continuum mechanics to study a material’s properties.
Multi-sensor system – It is a system which integrates data from multiple different types of sensors to collect a more complete and accurate representation of an environment or object. These systems use different sensors, such as optical, tactile, laser, radar, and chemical sensors, to monitor different signals simultaneously, providing a richer and more robust dataset for analysis than a single sensor can.
Multisim – It is a brand of computer software for electronic circuit simulation.
Multi slit rolling (MSR) – This process enables production of two, three, four or even five bars from one billet. The slitting process uses special passes and guides to prepare, shape and longitudinally separate the incoming material into two or more individual strands, which is then further rolled into the finished sizes. The process of slit rolling is to roll two or more bars simultaneously from a single billet. When compared with the conventional single strand continuous rolling, multi slit rolling process technology has reduced the number of passes. This process technology is very frequently used during the rolling of the ribbed reinforcement bars. The slit rolling process differs from conventional continuous rolling by the use of special roll passes and guides to prepare, shape and longitudinally separate the incoming billet into two or more individual strands for further rolling into the finished size. In principal, this process is achieved by (i) reducing the billet conventionally through the roughing and intermediate rolling mill stands to produce an acceptable section for the first special shaping pass at the forming stand, (ii) precise guidance of this rolling stock to the forming stand where it is reduced and shaped to form a symmetrical ‘forming section’ normally in the shape of a dog bone, (iii) further close guidance and control of the dog bone through the separating stand, where the rolling stock is reduced and shaped into a ‘slit pass’, designed to be easily separated into two equal sections of false round, and (v) a special guide on the delivery side of the separating stand ensures a clean slitting of the bar and now delivers multiple strand of equal sections to their respective finishing lines.
Multi-spectral image – It is a collection of images of the same scene, with each image layer captured at a specific and discrete wave-length band across the electro-magnetic spectrum. Unlike a standard digital camera which only captures red, green, and blue, a multi-spectral sensor can collect data from bands in the visible spectrum and beyond, such as near-infrared, short-wave infrared, and thermal infrared.
Multi-spectral imaging – It is a technique which captures image data across specific, narrow wave-length ranges of the electro-magnetic spectrum, including light invisible to the human eye, such as infrared and ultraviolet. Unlike standard RGB cameras which that use only red, green, and blue light, multi-spectral imaging uses multiple, frequently non-overlapping, spectral bands to gather detailed information about an object’s properties. This allows for the analysis of characteristics that are not visible in a regular colour photo, making it useful for several applications.
Multi-stage – It refers to a system, process, or method which involves multiple sequential or parallel stages to achieve a final outcome. This is seen in applications like multistage compressors, which use multiple series of compressors to achieve high pressure. It is a concept used to design complex systems which operate in steps, with each stage performing a specific function to contribute to the overall goal.
Multi-stage amplifier – It is an electronic circuit which combines two or more individual amplifier stages in series (cascade) to achieve a much higher overall voltage, current, or power gain than a single stage can provide. The output of one stage is fed into the input of the next, allowing each stage to amplify the signal further and producing a combined gain equal to the product of the individual stage gains.
Multi-stage burners – These burners are normally two-stage or three-stage burners which are set for running at one or more reduced output speeds or at maximum output with switchover from one stage to another stage which can be automatic or manual. Two-stage burners also include versions called progressive two-stage, where changeover from one stage to another is through a gradual increase in output and not with sudden step increases.
Multi-stage compression – It is a process where a gas is compressed in a series of stages, with each stage performing a portion of the total compression. The gas is cooled between stages, typically using an intercooler, to reduce its temperature and volume, which makes further compression more efficient and needs less power. This method is used to achieve higher final pressures than a single-stage compressor can efficiently, while also limiting the maximum temperature and pressure per cylinder.
Multi-stage compressor – It is a type of compressor which uses multiple stages of compression to achieve high pressure ratios, with each stage increasing the pressure of the gas sequentially. Between stages, the gas is cooled, which reduces its volume and makes further compression more efficient. This process allows for higher pressures to be reached than a single-stage compressor, while also using less energy and improving efficiency.
Multi-stage expansion – It refers to a process where expansion is broken down into multiple steps or stages to improve efficiency and performance. This is normally used in contexts like refrigeration systems with multiple expansion valves for better control, or power distribution network planning where infrastructure is expanded incrementally over time. It differs from single-stage methods by managing change in phases, leading to benefits like higher efficiency or more flexible, long-term planning.
Multi-stage flash distillation – It is a process for desalination where pre-heated seawater is flashed into steam in a series of stages, each at a progressively lower pressure, to produce fresh water. The heat from the steam is recovered by using it to preheat incoming seawater in heat exchangers within each stage, making it a thermal process which is reliable for large-scale operations but energy-intensive.
Multi-stage operation – It is a process which involves multiple sequential or parallel stages to achieve a final product or service. This approach is used across several fields, such as manufacturing, chemical processing, and electronics, to perform different steps of a process or to increase the overall performance and efficiency of a system. For example, a multi-stage pump increases pressure with each successive impeller, and a multi-stage amplifier increases the signal gain through a series of stages.
Multi-stage pump – It is a pump which contains two or more pump mechanisms with fluid being directed to flow through them in series.
Multi-stage system – It is a process or device which uses multiple, sequential components or stages to achieve a final result. These systems are common in different fields, from manufacturing to power generation, and are designed to perform tasks under different conditions or to achieve a higher level of efficiency by breaking down a complex process into smaller steps. Examples include multistage pumps and compression systems.
Multi stand pipe mill (MPM) – It is the continuous mandrel rolling process which has arrangement in tandem several rolling passes in a series of rolling stands to form a rolling line. This mill type elongates the hollow shell pierced in the piercing mill over a floating mandrel bar acting as an internal tool to produce the finished pipe. In recent times, rolling practice in mills of this type employs controlled instead of freely floating mandrel bars. The advantage of this process variant lies in fact that substantially shorter and fewer mandrel bars are required. The multi stand pipe mill (MPM) is part of an efficient seamless pipe hot rolling process from the hot pierced shell. The mill is normally composed of 8 stands of two grooved rolls inclined by 90-degree from one stand to another. The material is mounted on a cooled and lubricated mandrel and pushed to the first stand where rolling begins. The mandrel runs along the multi stand pipe mill with constant speed. The tube is then cut, calibrated, treated and controlled before delivery.
Multi-tubular fixed bed reactor – It is a type of chemical reactor where a catalyst is packed inside several parallel tubes. A heat transfer medium, typically a coolant, flows around the tubes in the shell to remove or add heat, making it ideal for exothermic or endothermic reactions. These reactors are designed to handle large volumes, improve heat and mass transfer, and control reaction temperature for processes like the oxidation of propylene to acrylic acid.
Multi-variable controller – It is a system designed to manage a process with multiple interconnected inputs and outputs simultaneously, unlike simpler single-loop controllers. It uses multiple manipulated variables to control multiple controlled variables, frequently employing advanced techniques like model-predictive control (MPC) to account for interactions between loops, which are common in complex systems like chemical plants.
Multi-variable regression – It is also known as multiple regression or multivariate regression. It is a statistical technique which examines the relationship between one dependent variable and two or more independent (predictor) variables. It aims to understand how changes in the independent variables collectively influence the dependent variable, allowing for predictions and insights into the relationships within the data.
Multi-variable studies – It is also known as multivariate studies. These studies involve the analysis of datasets where multiple measurements are taken on each experimental unit and the relationships among these measurements are examined. In essence, they analyze how several variables interact and influence an outcome simultaneously, rather than looking at each variable in isolation. This approach is useful for understanding complex systems where multiple factors play a role.
Multi-variable system – It is a process with multiple inputs and multiple outputs, where changes in any input can affect several outputs simultaneously. These systems need a coordinated control strategy since the different loops are frequently interconnected and interacting. Examples include chemical plants and cleanroom pressure control, all of which manage multiple manipulated and controlled variables.
Multivariate (or multivariable) analysis – It is an analysis in which one examines the simultaneous effect of two or more explanatory variables on a study end point.
Multivariate data – It is a dataset with more than two variables per observation, and multivariate analysis involves studying the relationships and interactions among these variables simultaneously. Unlike analyzing one variable at a time, this approach helps identify complex patterns, understand how multiple factors influence each other, and can be used to make predictions.
Multivariate normal distribution – It is a multi-dimensional version of the normal distribution which characterizes a collection of variables. If a set of variables has a multivariate normal distribution, then the variables are all inter-correlated and each individual variable is normally distributed.
Multivariate probability distribution – It describes the probabilities of a set of two or more random variables, showing how they might be related to each other. It’s essentially a joint probability distribution for a random vector, specifying the likelihood of different combinations of values for those variables.
Multivariate regression analysis – It is a statistical technique which models the linear relationship between multiple independent variables (predictors) and multiple dependent variables (responses). It helps engineers understand how several input factors (like temperature, pressure, or material properties) simultaneously influence different outcomes (like strength, efficiency, or product lifespan). This analysis is important for predicting system behaviour, identifying the most influential factors, and optimizing designs by finding the best balance between multiple performance metrics.
Multivariate statistics – It is a subdivision of statistics encompassing the simultaneous observation and analysis of more than one outcome variable, i.e., multivariate random variables. Multivariate statistics concerns understanding the different aims and background of each of the different forms of multivariate analysis, and how they relate to each other. The practical application of multivariate statistics to a particular problem can involve several types of univariate and multivariate analyses in order to understand the relationships between variables and their relevance to the problem being studied. In addition, multivariate statistics is concerned with multivariate probability distributions, in terms of both (i) how these can be used to represent the distributions of observed data, (ii) how they can be used as part of statistical inference, particularly where several different quantities are of interest to the same analysis.
Multi-walled carbon nano-tubes – These are cylindrical structures made of multiple concentric layers of carbon atoms, with each layer being a graphene sheet rolled into a tube. They are valued for their exceptional mechanical strength, high thermal and electrical conductivity, and large surface area. These properties make them useful in composites, electronics, and as catalyst supports.
Multi-zone model – It is a computational method which divides a building or system into multiple interconnected regions, or ‘zones’, to analyze the flow of air, heat, or other fluids. Each zone is treated as a single volume with uniform properties, and the model calculates the movement and exchange between these zones through ‘conductances’ representing openings like cracks or ducts. This approach allows for more detailed analysis than a single-zone model by accounting for pressure differences, temperature variations, and airflow dynamics within complex structures.
Murphy’s law – It is a popular adage which states, ‘anything that can go wrong, will go wrong’. It is a humorous and pessimistic observation which frequently highlights the tendency for errors to occur, especially in situations with multiple variables or a possibility for failure.
Mushet steel – It is an air hardened steel containing around 2 % carbon, 2 % manganese, and 7 % tungsten. It is also known as Robert Mushet’s Special Steel. It is at the time of its use is a self-hardening and air-hardening steel. It is considered to be both the first tool steel and the first air-hardening steel. It has been invented in 1868 by Robert Forester Mushet.
Mushroom-like structure – It is a formation with a central stem and a broader cap which appears in several fields, including geology and can also refer to specific architectural designs. In geology, it refers to ‘mushroom rocks’ eroded by wind. In fluid dynamics, it is a vortex structure formed by heated fluid, and in architecture, it is a type of column with a cap that resembles a mushroom.
Mushy region – It is also known as mushy zone, In the context of solidification or melting. It refers to a material state where both solid and liquid phases coexist, creating a mixture which is neither fully solid nor fully liquid. It is characterized by an enthalpy (a measure of heat content) which falls between the enthalpy of the solid and liquid phases. This region typically appears during solidification when the interface between solid and liquid is not sharp but rather a dendritic or branched structure. In a blast furnace, mushy zone
Mushy stage – It is the state between sold and liquid in alloys which freeze over a wide range of temperatures. It is a region where both solid and liquid phases coexist during melting or solidification.
Mushy zone – It is the zone in blast furnace where soft structure of the ferrous burden is formed at temperatures of around 1,100 deg C.
Music wire – It is the most widely used of all spring materials for small springs since this wire is the toughest. It has the highest tensile strength and can withstand higher stresses under repeated loading conditions than any other spring material. It is available in diameters from 0.12 millimeters to 3 millimeters. It has a usable temperature range from 0 deg C to 120 deg C. Music wire contracts under heat and can be plated.
Mutual capacitance – It refers to the capacitance measured between excitation and reception electrodes, needing at least two electrodes to form a measurement. It is characterized by changes in capacitance because of the disruption of capacitive coupling when an external object is present.
Mutual diffusion – It refers to the process in which different species in a multi-component solution diffuse at different rates, allowing for variations in diffusion coefficients and interactions, unlike binary diffusion where the components diffuse at the same speed. It is influenced by electrostatic interactions and requires knowledge of diffusion coefficients, electric conductivity, and transference numbers for accurate predictions.
Mutual gravitational attraction – It refers to the gravitational force which acts between particles because of their masses, causing them to exert forces on one another, as exemplified by particles located at the vertices of an equilateral triangle.
Mutual interaction – It refers to the process by which agents within a system communicate or influence each other, typically through message passing or by effecting changes in their shared environment.
Mutual interference – It refers to the phenomenon where multiple probes, particularly in directed-energy missions, become sources of unwanted radiation to each other when their downlink operations overlap in time, complicating signal separation and reception.
Mutually exclusive events – In probability theory, two events are said to be mutually exclusive if and only if they are represented by disjoint subsets of the sample space, namely, by subsets which have no elements or events in common. By definition the probability of mutually exclusive events A and B occurring is zero.
Mutually perpendicular planes – These refer to three planes which intersect at right angles, which are characteristic of orthotropic materials and are used to define their symmetry properties.
m-value – It is the increase in stress needed to cause a certain increase in plastic strain rate at a given level of plastic strain and a given temperature.
MXenes – These are a class of two-dimensional inorganic compounds along with MBorenes, which consist of atomically thin layers of transition metal carbides, nitrides, or carbonitrides. MXenes accept a variety of hydrophilic terminations. The first MXene was reported in 2011 at Drexel University’s College of Engineering, and was named by combining the prefix ‘MAX’ or ‘MX’ (for MAX phases), with ‘ene’ by analogy to graphene
Mylar – It is a trade name for a polyester film which is used as a release sheet in adhesive and composite bonding. It is also used as food packaging.
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