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Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘K’ 

• satyendra
• November 8, 2024
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• Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘K’,

Glossary of technical terms for the use of metallurgical engineers

Terms starting with alphabet ‘K’ 

Ka-band – It refers to a high-frequency microwave range (roughly 27 giga-hertz to 40 giga-hertz) of the electro-magnetic spectrum, known for enabling high-bandwidth, high-data-rate applications like satellite internet, mobile broadband, and high-resolution radar, though its shorter wave-lengths make it more susceptible to atmospheric interference (rain) than lower bands like Ku-band, needing advanced mitigation techniques. The ‘Ka’ comes from the German ‘Kurtz-above’, denoting its position above the original K-band.

Kaikaku – It is a critical element within the Lean manufacturing framework representing a profound paradigm shift, embodying the Japanese term for radical change. Distinguished from the incremental nature of continuous improvement, Kaikaku seeks to dismantle and radically overhaul existing processes. This method is particularly invoked when gradual improvements are insufficient to address the evolving challenges or objectives of an organization. Kaikaku is about breaking away from entrenched norms and methodologies to foster significant, comprehensive transformations. By adopting this approach, organizations aim to achieve monumental cost savings, boost efficiency to new heights, and elevate quality standards. The implementation of Kaikaku needs a bold vision and a willingness to re-engineer processes from the ground up, making it a potent tool for the organizations facing the need for drastic operational changes.

Kaizen – It is a concept referring to organizational activities that continuously improve all functions and involve all employees from the top management to the workers at the shop floor. Kaizen also applies to processes, such as marketing, purchasing and logistics, that cross organizational boundaries. Kaizen aims to eliminate waste and redundancies. Kaizen can also be referred to as zero investment improvement (ZII) because of its utilization of existing resources.

Kaizen Teian – It refers to a system of continuous improvement where employees actively participate in proposing and implementing small, incremental changes to improve their own work processes and the workplace environment. It is a bottom-up approach to Kaizen, focusing on empowering employees to identify and solve problems at the point of work.

Kaizen suggestion – It refers to a proposal for improvement submitted by an employee, frequently as part of a Kaizen suggestion scheme, to improve processes, products, or services within an organization. Kaizen, meaning ‘change for the better’ or ‘continuous improvement’, encourages employees to actively participate in identifying and solving problems, leading to incremental yet significant improvements.

Kahlbaum iron – It is an iron of more than 99.975 % purity.

Kalina cycle – The Kalina cycle is a variation of the Rankine cycle, using a mixture of ammonia and water as the working fluid. A key difference between single fluid cycles and cycles which use binary fluids is the temperature profile during boiling and condensation. For single fluid cycles, the temperature remains constant during boiling. As heat is transferred to the working medium (water), the water temperature slowly increases to boiling temperature, at which point the temperature remains constant until all the water has evaporated. In contrast, a binary mixture of water and ammonia (each of which has a different boiling point) increases its temperature during evaporation. This allows better thermal matching with the waste heat source and with the cooling medium in the condenser. Consequently, these systems achieve considerably greater energy efficiency.

Kalling-Dommarfvet process – It is a historical metallurgical method for desulphurizing molten iron using powdered burnt iron.

Kalman filter – It is an algorithm which uses a series of measurements observed over time, including statistical noise and other inaccuracies, to produce estimates of unknown variables that tend to be more accurate than those based on a single measurement, by estimating a joint probability distribution over the variables for each time-step. The filter is constructed as a mean squared error minimizer, but an alternative derivation of the filter is also provided showing how the filter relates to maximum likelihood statistics.

Kanban – It is a scheduling system for lean manufacturing. The system takes its name from the cards that track production within a factory. A goal of the kanban system is to limit the buildup of excess inventory at any point in production. Limits on the number of items waiting at supply points are established and then reduced as inefficiencies are identified and removed. Whenever a limit is exceeded, this points to an inefficiency that should be addressed. In kanban, problem areas are highlighted by measuring lead time and cycle time of the full process and process steps. One of the main benefits of kanban is to establish an upper limit to work in process (normally referred as ‘WIP’) inventory to avoid overcapacity.

Kanbara reactor (KR) – It is a mechanical mixer-type hot metal desulphurization facility. It is characterized by its acceleration of the desulphurization reaction through the submersion and rotation of an impeller in hot metal, and subsequent mechanical mixing of the hot metal and desulphurizing agent.

Kanbara reactor (KR) process – It is a method for desulphurizing hot metal. It involves using a mechanical mixer to stir the hot metal and a desulphurizing agent, accelerating the removal of sulphur from the iron. The process has been developed in Japan by Nippon Steel in the 1960s. Kanbara reactor process efficiently advances the desulphurization reaction by means of high-speed (around 120 revolutions per minute) rotation of the impeller. As a result, it enables the reduction of sulphur concentration in the hot metal to low levels of within several dozen ppm (parts per million) using only inexpensive lime as a desulphurizing agent, without the need for expensive magnesium. Desulfurizing agent costs can be significantly reduced by replacing injection-type desulphurization facilities which use magnesium and calcium carbide with Kanbara reactor.

Kangaroo crane – It is also known as a self-erecting or jumping crane. it is a type of tower crane which can lift itself to higher levels as a building grows, allowing it to reach extreme heights without needing larger cranes for setup. Its name comes from its ability to ‘jump’ by detaching its base, raising itself, and re-securing to the structure, much like a kangaroo hopping, making it crucial for sky-scraper construction.

Kano model – It is a theory for product development and customer satisfaction. This model provides a framework for understanding how different features of a product or service impact customer satisfaction, allowing organizations to prioritize development efforts effectively. As per the Kano model, customer preferences are classified into five distinct categories, each representing different levels of influence on satisfaction.

Kaolin – It is a clay mineral, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO4) linked through oxygen atoms to one octahedral sheet of alumina (AlO6). Kaolin is a soft, earthy, usually white, mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. It has a low shrink–swell capacity and a low cation-exchange capacity. In many parts of the world kaolin is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lower concentrations of iron oxide yield the white, yellow, or light orange colours of kaolin. Kaolin is an important raw material in several industries and applications.

Kaolinite – It is a soft, white, clay mineral [hydrated aluminum silicate, Al2Si2O5OH)4] formed from feldspar weathering, known as china clay and prized for its brightness, chemical inertness, and fine texture, making it necessary in paper, ceramics (porcelain), and paints. It is characterized by its 1:1 layered structure, low shrink-swell, and low cation-exchange capacity, giving it unique stability and utility across several industries.

Kaowool – It is a type of high-temperature mineral wool made from the mineral kaolin. It is a type of high-temperature mineral wool. It can withstand temperatures close to 1,650 deg C.

Kaplan-Meier estimator – It is also known as known a product-limit. It is a non-parametric estimator of the survival function in correlation survival analysis.

Kaplan turbine – It is a highly efficient, axial-flow, reaction turbine featuring adjustable propeller-like blades, designed to generate electricity from low-head (moderate water height) and high-flow (large water volume) hydroelectric sources, making it ideal for rivers and run-of-river projects by optimizing energy capture across varying conditions.

Kappa carbide (κ-carbide) – It i are a special class of carbide structure. It is a specific, ordered crystalline structure, typically with the formula (Fe,Mn)3AlC, which forms in advanced low-density steels containing high quantities of aluminum (Al) and manganese (Mn). It is important for strengthening these steels, providing a balance of high strength and ductility when finely dispersed, appearing as tiny particles (like rods or plates) within the metal matrix, and influencing the material’s overall mechanical properties

Kapton – It is the trade name for a polyimide film which emits low smoke and flame, resists hydraulic fluids, and has good low-temperature and high-temperature performance.

Karat – It is a unit for designating the fineness of gold in an alloy. In this system, 24 karat (24 k) is 1,000 fine or pure gold. Table 1 gives the most popular jewelry gold qualities.

Karman vortex street – When a body is placed in the middle of a media flow, separation occurs and vortices are formed on both sides if velocity or Reynolds number R is above a certain value. It is interesting to note, that after a vortex has formed on one side a similar vortex forms on the other side which causes the first one to be shed. That periodic vortices are shed from each side alternately was discovered by Karman after whom the vortex street is named. These usually undesirable vortices are utilized as the basis for the measurement in vortex flow meters.

Karst and Quaternary process – Karst refers to a landscape formed by the dissolution of soluble rocks like limestone, creating features like sinkholes, caves, and underground streams, while Quaternary processes encompass the geological events and landform changes that occurred during the most recent geological epoch, the Quaternary period, which includes periods of glaciation and significant climate fluctuations. Essentially, karst features can be significantly influenced by Quaternary processes like glacial meltwater, which can accelerate the dissolution of rock and shape karst landscapes.

Kata – It means a structured way of doing things or practice, i.e., the form and order of doing things. Obsession with quality and executing processes in the correct and appropriate order is deeply rooted in Japanese culture. Instead of rushing to fix a problem when a person has little to no insight, Kata encourages thinking before doing.

Kawabata evaluation system – It is a standardized method using specialized instruments to objectively measure a fabric’s mechanical and surface properties (like bending, shearing, compression, friction) to predict its subjective ‘hand’ or feel, allowing for engineered quality control, product development, and consistent tactile comfort in textiles. It translates human touch sensations into quantifiable data, bridging the gap between subjective perception and objective material science for consistent textile quality.

Kawasaki basic oxygen process (K-BOP) – In the operation of this process, 30 % of the oxygen is soft blown from a multi-hole lance set high above the steel bath, with the remainder injected through the base of the vessel using shrouded tuyere technology. This allows low turndown carbons (of the order of 0.02 % carbon to 0.04 % carbon), together with higher scrap-melting capabilities (e.g., 33 % against 30 % of the charge).

Kawasaki sinter automatic control (K-SAC) – It is an advanced automation and control system for sinter plants developed by the Japanese company Kawasaki Steel Corporation (KSC). It is designed to optimize the iron ore sintering process, which is a complex and energy-intensive step in iron-making. The Kawasaki sinter automatic control system is a process control system which raises plant automation to a new level by integrating a range of metallurgical models and providing comprehensive operational guidance. Its primary objectives include (i) improving productivity and quality, (ii) reducing operational costs, (iii) ensuring stable operation, and (iv) enhancing environmental compliance. Kawasaki sinter automatic control is part of a multi-level hierarchical automation structure (distributed control system, process computer, central computer system) which uses specialized sensors and advanced data processing to monitor and manage the several process parameters involved in sintering.

Kaya Identity – It is a formula which breaks down total carbon di-oxide emissions into four key drivers namely population (P), GDP (gross domestic product) per capita (G/P), energy Intensity (E/G), and carbon intensity (F/E), showing how these factors multiply to determine national or global carbon output, helping analyze pathways to reduce emissions.

Kayser hardness test – It is a method for determining the true hardness of metals at high temperatures.

KBR TRIG coal gasifier – The Transport Integrated Gasification (TRIG) technology was developed by the Southern company and KBR Inc. It is designed to process reactive low rank coals, including those with up to 50 % ash and high moisture content, and can be operated with steam and either air or O2 as the gasification medium. Air-blown operation is preferable for power generation, while O2 blown operation is better suited for syngas production. The system comprises a circulating gasifier, which consists of a mixing zone, riser, disengager, cyclone, standpipe, loop seal, and J-leg. This is designed to operate at high solids circulation rates and gas velocities, resulting in higher throughput, C conversion and efficiency. The raw syngas is formed in the riser portion of the unit, from which laden with unreacted solids it passes through a series of cyclones where the solids are removed. The ash material is recirculated through the riser to allow unconverted C to be utilized and to provide heat to the gasifier. As ash accumulates in the down comer, it is discharged from the unit. The gasifier operates at moderate temperatures and below the melting point of ash, which can increase the equipment reliability and availability. The latter is enhanced by the use of a downstream particulate filter, which eliminates water scrubbing and significantly reduces plant water consumption and effluent discharge.

Kc (Plane-stress fracture toughness) – It is is the critical stress intensity factor (Kc) which indicates a material’s resistance to crack propagation under conditions where the material’s thickness is small, allowing substantial plastic deformation (yielding) at the crack tip, leading to more ductile failure, unlike thicker sections which show plane-strain (brittle) fracture. It is a material property used in fracture mechanics to predict failure in components with pre-existing flaws, with higher Kc values signifying higher resistance to fracture.

KCS process – This process has been developed by Kawasaki Steel (now JFE). This process smelts chromite ore (FeCr2O4 plus other oxides). Stainless steel is produced with 160-ton converters, without any electric arc furnace (EAF) operation, but using dephosphorized hot metal, chromite ore, and ferro-alloys as the major charge materials. The hot metal is desulphurized and then fed into a K-BOP / K-OBM converter (SR-KCB). Chromite pellets, which are partially pre-reduced up to 60 % chromium content in a rotary kiln, are charged to the first reactor. Coke is also charged and serves as a heat source in the reactor. The charging rate of ore and coke and the oxygen blow rate are controlled to achieve suitable temperature for the melt. The liquid steel, which now contains around 11 % chromium to 16 % chromium and 5 % carbon to 6 % carbon is charged to the second KBOP / K-OBM converter. Primary decarburization (DC-KCB) is carried out using oxygen, argon, and nitrogen gases in this converter. Top and bottom oxygen blowing is used for lowering the carbon content of the liquid steel to around 1 % level. This is followed by mixed gas blowing only from the bottom. This is called the DC-KCB process and is similar to a modern AOD (argon oxygen decarburization) operation. The process reduces the carbon to around 0.15 %. Final decarburization and reduction are carried out in a VOD (vacuum oxygen decarburization) unit. The KCS process uses lesser quantity of scraps than the EAF-AOD process route. However, it needs liquid hot metal from a blast furnace and more process steps and more capital investment than the EAF-AOD route.

KDS Micronex (Kinetic disintegration system) – It is a patented, all-in-one machine which simultaneously grinds wet waste materials into fine, dry powder in a single step, using mechanical forces (kinetic energy) and centrifugal force, rather than external heat, to extract moisture. It efficiently combines grinding and drying, reducing energy use and simplifying processing for producing biofuels, fertilizers, or other valuable products from different organic wastes.

Kee Klamp – It is a structural pipe fitting commonly used in the construction of handrails and barriers. Fabricated installations comprise the fittings and separate tubing components, which can be sized on site.

Keel block – It is a standard test casting, for steel and other high-shrinkage alloys, consisting of a rectangular bar which resembles the keel of a boat, attached to the bottom of a large riser, or shrink head. Keel blocks which have only one bar are frequently called Y-blocks. Keel blocks which are having two bars are called double keel blocks. Test samples are machined from the rectangular bar, and the shrink head is discarded.

Keesom interaction -It is the interaction between two molecules with permanent dipole moments when they are placed in close proximity, where the positive end of one molecule aligns with the negative end of another, leading to an energy-minimized arrangement.

Kellogg-Rust-Westinghouse (KRW) gasifier – It is a pressurized, dry-feed, fluidized-bed gasifier which converts coal into syngas (synthesis gas) by mixing it with air / steam in a turbulent bed, using high-velocity jets for efficient contact and recycling unreacted char and sorbent for better conversion and sulphur capture, making it robust for different coals but needing careful management of tar.

Kelvin (K) – It is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute thermodynamic temperature scale which uses absolute zero as its null point.

Kelvin’s circulation theorem – It states that for an ideal (inviscid), barotropic fluid with conservative body forces (like gravity), the circulation (gamma) around a closed loop moving with the fluid remains constant over time (d gamma/dt). This means the total ‘swirling’ motion (circulation) of a fluid parcel group does not change unless viscosity, compressibility (non-barotropic), or non-conservative forces act, explaining lift generation on wings via the creation of starting vortices.

Kelvin connection – It is four-wire sensing. It is a high-precision method for measuring electrical resistance or voltage by using separate pairs of wires for current application (force) and voltage measurement (sense), effectively eliminating errors from wire resistance and contact points. It is important for low-resistance measurements (e.g., less than 1 ohm) and high-current scenarios.

Kelvin equation – It is a mathematical relationship which relates the vapour pressure of a liquid in a curved interface to the radius of curvature, accounting for surface tension and the contact angle. It is normally used in membrane characterization techniques to calculate pore diameters based on vapour pressure measurements.

Kelvin-Helmholtz instability – It is a fluid dynamics phenomenon occurring at the interface between two fluids (or within one fluid) with different velocities, causing small disturbances to grow into visible, swirling patterns like waves or vortices because of the velocity shear, mixing fluids, and transferring energy and momentum, normally seen in clouds, planetary atmospheres, and plasmas. It is driven by the velocity difference (destabilizing) against density differences (stabilizing), leading to fluid mixing and turbulence.

Kelvin temperature scale – It is an absolute temperature scale which starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol degree C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 deg C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15.

Kelvin-Stokes theorem – It is a theorem in calculus, useful in analytic solutions of problems in electro-magnetism.

Kelvin-Voigt model – It is a simple mechanical model for viscoelastic materials, representing them as a purely elastic spring and a viscous dashpot connected in parallel, describing materials which show both elastic (spring-like) and viscous (dashpot-like) behaviours, especially good for modeling creep (time-dependent deformation under constant stress) in polymers and rubbers. The total strain equals the sum of strains in the spring and dashpot, while the total stress is shared between them, governing material response over time.

Kendall’s coefficient of rank – Denoted as ‘t’ij, where i and j refer to two variables, Kendall’s coefficient of rank correlation reflects the degree of linear association between two ordinal variables, and is bounded between +1 for perfect positive correlation and –1 for perfect negative correlation.

Kentledge, kentledge weights – These are slabs or blocks of concrete or iron (normally pig iron, sometimes with a cast-in handle to assist moving). They are used as counterweights in cranes such as tower cranes or swing bridges. On construction sites, prior to the erection of a building, static load testing can use a large number of kentledge stacked onto a platform. This platform is used to drive piles into the ground beneath to test the integrity of the foundation.

Kerf – It is the width of the cut produced during a cutting process. It is the width of a cut made by a saw blade, torch, waterjet, laser beam, and so forth.

Kermel – It is a high-performance meta-aramid technical fibre which is naturally non-flammable, provides very good thermal insulation, and shows good resistance to mechanical stress and chemicals. It is characterized by its circular cross-section, low modulus for comfort, and lifelong colour fastness because of its spun-dyed manufacturing process.

Kernel – It is a core component of an operating system and serves as the main interface between the computer’s physical hardware and the processes running on it. The kernel enables multiple applications to share hardware resources by providing access to central processing unit (CPU), memory, disk input/output (I/O), and networking.

Kernel covariance – It is also called covariance function. It defines the similarity or correlation between data points, acting as a fundamental component in Gaussian processes to model function smoothness and structure by determining how much the output values at different inputs vary together. It is a symmetric, positive-definite function k(x, x’) which generates valid covariance matrices, encoding assumptions like smoothness or periodicity. It is important for making predictions and quantifying uncertainty in Bayesian modeling.

Kernel mode – It is also called supervisor mode. It is the highly privileged execution state where the operating system’s core (the kernel) runs with unrestricted access to all system resources, including memory and hardware, to manage critical functions like process scheduling, memory management, and device drivers, contrasting with the restricted user mode where applications run and id required to make system calls to access hardware.

Kernel size – It is the width of the window used in kernel density estimation, which acts as a spatial filter that determines the level of smoothing and detail in the density map. Smaller kernel sizes reveal local variations, while larger sizes provide a smoother representation of regional patterns.

Kerogen – It is the naturally occurring, solid, insoluble organic matter found in sedimentary rocks which serves as the precursor to oil and natural gas. It is insoluble in normal organic solvents because of its high molecular weight and complex cross-linked macro-molecular structure.

Kerosene – It is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Kerosene is widely used to power jet engines of aircraft (jet fuel), as well as some rocket engines in a highly refined form called RP-1. It is also commonly used as a cooking and lighting fuel.

Kerosene lamp – It is a portable light source which burns kerosene (paraffin) fuel, using a wick and frequently a glass chimney to create a steady, bright flame, normally used in areas without electricity or during power outages for tasks like cooking, heating, and illumination, though it poses safety and health risks from fumes and fire. These lamps feature a fuel tank, wick, adjustment knob to control brightness, and a glass globe for protection and airflow.

Kerr effect non-linearity – It describes how a material’s refractive index changes with light intensity, specifically as n = n0 + n2I, where ‘n’ is the refractive index, ‘n0’ is the linear index, ‘n2’ is the Kerr coefficient, and ‘I’ is light intensity. This third-order nonlinear optical effect means the material’s response is not proportional to the electric field (E) but to E square (intensity ‘I’), causing phenomena like self-focusing and self-phase modulation, important in optical fibres.

Kesternich test – It is also known as sulphur di-oxide testing. It is a corrosion test method which simulates the damaging effects of acid rain and industrial pollutants. It exposes materials to a controlled atmosphere of sulphur di-oxide (SO2) and moisture condensation to evaluate their corrosion resistance. The test is normally used to assess the performance of coatings, plated surfaces, and other materials which can be exposed to acidic environments.

Ketone – It is a class of organic compounds and a functional group composed of a carbonyl group between two carbon atoms. Ketones have the general formula R2C=O, where R can be any carbon-containing substituent.

Kettle – It is the molten zinc filled tank or pot where the metallurgical bonding of zinc and steel takes place.

Kettle reboiler – It is a horizontal shell-and-tube heat exchanger used at the bottom of distillation columns to boil liquid, creating vapour which rises back into the column to drive the separation process, while the unvapourized liquid is removed as the bottom product. Its simple design, high vapour quality, and reliability make it common in chemical and petro-chemical industries for efficient heat transfer and steady operation.

Kevlar – It is trade name for an organic polymer composed of aromatic polyamides having a para-type orientation (parallel chain extending bonds from each aromatic nucleus).

Kevlar fibre – It is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora.

Kevlar reinforcement – It is a unique form of material fortification used in conveyor belts, harnessing the strength and durability of Kevlar fibres. Essential routine inspections become imperative to validate the integrity and sustained performance of the reinforced conveyor belt.

Key – It is a machine element which is used to connect a rotating machine element to a shaft. The key prevents relative rotation between the two parts and can enable torque transmission. For a key to function, the shaft and rotating machine element must have a keyway and a keyseat, which is a slot and pocket in which the key fits. The whole system is called a keyed joint. A keyed joint can allow relative axial movement between the parts. In a furnace construction, key is the uppermost or the closing refractory brick of a curved arch.

Key brick – It is a brick made so that each narrow side is inclined at the same angle toward the end of the brick.

Key concepts – These are the fundamental, core ideas or principles which form the foundation for understanding a subject, topic, or text, acting as timeless, broadly applicable building blocks which help people grasp complex information beyond just memorizing details, enabling deeper comprehension and transferability across different contexts.

Key decision points – These are critical junctures or milestones in a project, process, or lifecycle where important, frequently irreversible choices are to be made, fundamentally influencing direction, success, resource allocation, and outcomes, acting as go / no-go gates for moving forward. They ensure alignment with objectives, manage risks, and involve assessing performance, budget, and requirements before committing to the next phase.

Key dimensions – These are the essential, defining characteristics or measures which provide a framework for understanding, analyzing, or categorizing something, whether it is a physical object (length, width, height), an organizational concept (scope, budget, time), product quality (performance, features, reliability), or data (customer, time, product) in data warehousing. They highlight the most critical aspects needed to describe, evaluate, or compare different entities within a specific context, helping to break down complexity into manageable, meaningful components.

K–epsilon model – It is a mathematical model used to describe turbulence behaviour and energy dissipation in fluid flow, facilitating the calculation of several required rate functions in several engineering applications.

Keyhole – It is a technique of welding in which a concentrated heat source, such as a plasma arc, penetrates completely through a work-piece forming a hole at the leading edge of the molten weld metal. As the heat source progresses, the molten metal fills in behind the hold to form the weld bead.

Keyhole sample – It is a type of sample containing a hole-and-slot notch, shaped like a keyhole, normally used in impact bend tests.

Keying – It is the deformation of metal particles during compacting to increase interlocking and bonding. In electrical connector, keying is used by electrical connectors to prevent mating in incorrect orientation. In graphics, keying is a technique for compositing two full frame images together.

Keyless entry systems – These refer to security systems which allow access to vehicles or buildings without the use of traditional keys, typically utilizing encrypted signals, such as those based on the Keeloq protocol, which employs 64-bit keys and encrypts 32-bit blocks.

Keyless locking device – It is a distinctive mechanical apparatus which is utilized for linking shafts devoid of a traditional key, necessitating regular scrutiny to ensure precise alignment and secure fastening, mitigating the risk of inadvertent disconnection.

Key optical component – It is a fundamental device which manipulates light (generates, transmits, reflects, focuses, or detects it) to enable photonic systems, acting as important building blocks for technologies like telecommunications, imaging, and astronomy, including elements such as lenses, mirrors, optical fibres, lasers, and detectors. These components work together to control light’s path, intensity, or spectrum for specific applications, ranging from basic reflection to complex signal processing.

Key parameters – These are the important, measurable factors or variables which considerably impact a system’s performance, quality, or outcome, acting as critical indicators for control, analysis, and decision-making in fields like engineering (e.g., temperature, pressure), finance (e.g., risk, profit), or programming (e.g., sort criteria). They define how well something works and are important for meeting requirements or optimizing results, with their alteration having major consequences.

Key performance indicator (KPI) – A Key performance indicator is a metric for measuring project success. Key performance indicators are established before project execution begins.

Key physical parameters – These refer to important measurable properties in industrial production processes which are monitored to improve product quality and optimize energy consumption. These parameters are critical for ensuring process transparency and supporting data-driven modeling for complex production environments.

Key process – It is a vital, high-impact sequence of activities which directly creates value, generates revenue, or fulfills the core mission of an organization, impacting customers and strategic goals, such as sales, product development, or order fulfillment, and hence needing focused management for efficiency and success. These are the necessary ‘how’ behind an organization’s value proposition, differentiating them from supporting or management processes.

Key process parameters – These are essential variables in a manufacturing or industrial process, like temperature, pressure, or time, which considerably influence overall performance, efficiency, consistency, and output quality, even if not directly tied to a specific ‘critical quality attribute’ (CQA) like a final product’s purity. They are to be monitored to ensure the process runs smoothly and reliably, distinguishing them from ‘critical process parameters’ (CPPs) which directly affect final product quality.

Keystone – It is the wedge-shaped stone at the apex of a masonry arch or typically round-shaped one at the apex of a vault. In both cases it is the final piece placed during construction and locks all the stones into position, allowing the arch or vault to bear weight.

Key stop – It is a method of restricting the travel of a ball valve from fully open to fully closed and vice versa. The stem key bears against the ends of an arc machined in or attached to the adaptor plate.

Keyway – It is a recess in a shaft or hub designed to receive a key, facilitating the prevention of relative movement between two parts.

K-factor – It is the ratio between the unknown and standard X-ray intensities used in quantitative analyses. It is also the coefficient of thermal conductivity. The quantity of heat which passes through a unit cube of material in a given time when the difference in temperature of two opposite faces is one degree. In sheet metal, K-factor is a unitless ratio (0 to 1) representing the location of the neutral axis (the line that neither stretches nor compresses during bending) within the material’s thickness, important for accurately calculating flat patterns. It helps determine bend allowance and bend deduction, preventing errors by accounting for material compression on the inside and stretching on the outside of a bend, with typical values ranging from 0.25 to 0.5.  In electrical engineering, the K-factor quantifies a transformer’s ability to handle harmonic distortion from non-linear loads (like computers, light emitting diodes, and variable frequency drives), indicating extra heating. A higher K-factor means more harmonics and hence more heat, needing special K-rated transformers with larger conductors and cooling for safe operation, preventing overheating and failure. It is a measure of the ratio of these harmonic-induced losses to normal 60 hertz losses, helping size transformers for modern, sensitive electronic equipment.  In statistics, the k-factor (tolerance factor) is a multiplier used to calculate tolerance intervals, which provide a range that contains a specified proportion of a population with a certain level of confidence. The value of the k-factor depends on several parameters namely (i) the sample size (n), the desired proportion of the population to be covered (p), and (iii) the confidence level (frequently denoted as 1-alpha) which the interval actually contains the specified proportion.

kg dry air – It refers to a unit of mass representing one kilogram of dry air, which is used in calculations involving the humidity ratio and the physical properties of air mixtures.

kHz switching frequency – It defines how fast an electronic circuit (like a power converter or sensor) rapidly turns components on and off, measured in kilohertz (thousands of cycles per second), impacting efficiency, component size (smaller for higher frequency), and performance characteristics like heat and noise. A 40 kHz frequency means 40,000 on / off cycles per second, allowing smaller inductors but potentially increasing switching losses, balancing these trade-offs is key.

Kick-back – It is abnormal feed-back which results from slippage or rejection of the work-piece in the die taper when the dies are too oily or the taper is too steep. Kick-back manifests itself as a heavy endwise vibration which causes considerable resistance to feeding of the work-piece.

Kicker – It is also called column starter. It is a small, short concrete upstand (plinth) built at the base of where a column or wall is going to be cast, serving as a precise guide, support, and stop for the main formwork, ensuring correct alignment, preventing leakage, and creating a strong connection between floor and vertical elements.

Kick fluid – It refers to unwanted formation fluids (gas, oil, water) entering a well-bore during drilling, caused by formation pressure exceeding the drilling fluid’s hydrostatic pressure, creating a dangerous kick which, if uncontrolled, can lead to a blow-out. The fluid itself can be any combination of these reservoir fluids, with gas being the most hazardous.

Kick-off meeting – The first meeting between a project team and stakeholders. It serves to review project expectations and to build enthusiasm for a project.

Kick plates – These are specially crafted protective barricades strategically positioned along the conveyor sides to avert material spillage or protrusion. Periodic examinations are mandatory to ascertain their stability and sustained efficacy.

Kic (Plane-strain fracture toughness) – It is the critical stress intensity factor. The critical stress intensity factor for plane strain Kic is measured by bending the sample with artificially created single sharp crack of predefined or measurable size and geometry that is intentionally made larger than any other crack that might be present or developed in the specimen during the load to assure that it is this artificial crack that becomes critical under the load. It is defined as the plane strain fracture toughness. It is a measure of the resistance of a material to crack extension under predominantly linear-elastic conditions (i.e., low toughness conditions when there is little to no plastic deformation occurring at the crack tip).

Kieselguhr – It is a diatomaceous earth (diatomite) is a form of silica composed of the siliceous shells of unicellular aquatic plants of microscopic size. Kieselguhr is heat resistant. It is a finely porous material used for thermal insulation to 1,100 deg C. It is used as an abrasive in metal polishes. In the chemical industry, it is also used as a filter to clarify syrups and sugar and as a filling material in paper, paints, ceramics, soap and detergents.

Kikuchi diffraction pattern – It is a pair of bright (excess) and dark (defect) lines formed in ‘transmission electron microscopy’ (TEM) from thicker crystalline samples, resulting from Bragg diffraction of inelastically scattered electrons, creating ‘roads’ in orientation space used for precise crystal alignment and orientation mapping. These lines appear as bands (Kikuchi bands) corresponding to specific crystal planes (hkl), with the bright line further from the beam and the dark line closer, offering a detailed map of crystal structure.

Kikuchi lines – These are light and dark lines superimposed on the background of a single-crystal electron-diffraction pattern caused by diffraction of diffusely scattered electrons within the crystal. It is the pattern provides information on the structure of the crystal.

Killed steel – It is that steel which is treated with a strong deoxidizing agent such as silicon or aluminum in order to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification. Killed steels are made by complete deoxidation of the liquid steel before it is cast so that no gas evolution occurs during solidification. These are the steels to which normally aluminum, silico-manganese, ferro-silicon, or ferro-manganese is added as deoxidizing agents. Properly killed steel is more uniform in analysis and is comparatively free from aging. However, for the same carbon and manganese content killed steels are harder than rimmed steels. Normally, all steels above 0.25 % carbon are killed. Also, all forging grades of steels, structural steels from 0.15 % carbon to 0.25 % carbon and some special steels in the low carbon range are killed. Only killed steels can be cast in continuous casting machines.

Kiln – It is a large furnace which is used for baking, drying, or burning firebrick or refractories, or for calcining ores or other substances.

Kiln discharge head – The kiln discharge head serves two purposes. One purpose is to provide a place for product to leave the kiln, so that it can move on to subsequent processing. The second purpose is to mount the kiln burner in a counter-current system. The product discharge area is where product leaves the kiln. Typically, the product then moves on to cooling or subsequent processing if needed.

Kiln-dried – It means wood has been artificially dried in a large oven (a kiln) to precisely control heat, humidity, and airflow, quickly reducing its moisture content to a stable, workable level (frequently 10 % to 19 %) for uses like furniture, flooring, or construction, preventing warping, shrinking, and pest issues better and faster than natural air-drying.

Kiln furniture – It consists of devices and implements inside furnaces used during the heating of manufactured individual pieces, such as pottery or other ceramic or metal components. Kiln furniture is made of refractory materials, i.e., materials that withstand high temperatures without deformation. Kiln furniture can account for up to 80 % of the mass of a kiln charge.

Kiln inlet head – The kiln inlet head has exhaust gas system which is typically much larger when working with a direct-fired kiln. Here, exhaust gases and any small particulates leave the system and typically go through exhaust gas treatment to remove contaminants before being discharged into the environment or sent to waste heat gas boiler for waste heat recovery. The exhaust gas system on a kiln often needs an afterburner and heat exchanger or quench tower to cool the gases before they enter the bag filter.

Kiln marks – These are irregularities on the surface of refractories caused by deformation under load during burning.

Kiln refractories – Refractory serves the purpose of insulating and protecting the shell of the drum from the high temperatures within, and also minimizing heat loss. Refractory lining is an important component of the rotary kiln. An important factor determining the service life of the refractory lining is the mechanical stability of the shell. The thickness, physical properties, and chemical composition of the refractories used for the lining are decided by the process to be carried out. For example, in the kiln used for iron ore reduction, low-iron alumina or magnesium – spinel bricks are used, while in a cement kiln usually magnesite brick lining in the clinker zone and acid-insulating brick made from silicate compounds in the preheating zone are used. Interlocking bricks (with tapered groove and tongue) are used in large diameter rotary kilns. Monolithic refractories are also used in some applications. Qualities of refractories and lining techniques improve significantly the service life of linings. Insulating bricks lining is very desirable for heat retention but have not proved useful in kilns in larger diameter kilns.

Kiln, rotary – A rotary kiln is an inclined, rotating cylindrical reactor through which a charge moves continuously. The rotary kiln is a thermal processing furnace used for processing solid materials at extremely high temperatures in order to cause a chemical reaction or physical change. They are normally used to carry out processes such as (i) calcination, (ii) thermal desorption, (iii) organic combustion, (iv) sintering/induration, (v) heat setting, and (vi) many more processes.

Kiln sizing – It is the complex process of determining the optimal dimensions (length and diameter) of a kiln to meet specific material processing requirements and production capacity. It is a customized design process which combines engineering principles with extensive thermal and chemical analysis of the material to be processed.

Kilo – It is a decimal unit prefix in the metric system denoting multiplication by one thousand (1000). It is used in the International System of Units, where it has the symbol ‘k’, in lowercase.

Kilobyte – It is a unit of data measurement, typically meaning 1,024 bytes in binary contexts (memory / RAM) and sometimes loosely 1,000 bytes in decimal contexts (storage / networking), representing a fundamental small unit for measuring digital information, like a short text paragraph, reflecting binary system’s base-2 math.

Kilocalorie – It is a unit of heat energy equal to the energy needed to raise 1 kilogram of water by 1 degree Celsius, normally used in thermal calculations, though the SI (International System of Units) unit is the joule (J). It is defined as 1,000 small calories, around 4.184 kilojoules (kJ). It indicates a practical measure of thermal energy, especially when dealing with water or in contexts like HVAC (heating, ventilation, and air conditioning), representing a large, easily visualized quantity of heat.

Kilogram – It is the SI (International System of Units) base unit of mass, redefined in 2019 to link to fundamental physical constants, specifically the Planck constant (h), rather than a physical artifact (like the old platinum-iridium cylinder). The current definition sets the kilogram as exactly 6.62607015 x 10 to the power -34 kilograms meter squared per second. This is realized practically using Kibble balances, which link mass to electromagnetic force and quantum effects, allowing for highly precise and stable mass calibration.

Kilogram-force – It is a non-SI (International System of Units) unit of force representing the weight of a 1-kilogram mass under standard earth gravity, defined as around 9.80665 Newtons (N), used historically in gravitational metric systems (MKS) for practical applications like material testing (Vickers hardness) and construction, despite the modern SI system preferring Newtons for force.

Kilohertz -It is a unit of frequency equal to 1,000 hertz, representing 1,000 cycles or oscillations per second, normally used for radio waves, audio signals (digital audio sampling rates), and electronic circuit speeds (like processor clock frequencies). It provides a convenient way to measure faster events than single Hertz but slower than mega-hertz (MHz) or giga-hertz (GHz).

Kilonewton – It is a unit of force equal to 1,000 Newtons (N) and is used to measure large forces like engine thrust, structural loads, and safety limits, where 1 kilonewton represents the force needed to accelerate 1,000 kilograms at 1 meter per square second or roughly 100 kilograms of weight on earth. It is a convenient SI (International System of Units) unit for structural design, simplifying calculations for high-magnitude forces.

Kilovolt (kV) – It is a unit of electrical potential equal to 1,000 volts.

Kilovoltage peak – It is the maximum electrical potential difference applied across an X-ray tube, representing the highest energy level (in kilo-volts) which accelerates electrons to strike the anode, thereby determining the penetrating power (quality) and intensity (quantity) of the X-ray beam, which controls image contrast and patient dose in medical imaging. A higher kilo-voltage peak creates more energetic, penetrating X-rays, affecting image density and contrast, making it a fundamental control for image quality.

Kilovolt-ampere – It is a unit of measurement of apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). Volt-amperes product is equal to the real power, measured in watts. The volt-ampere is dimensionally equivalent to the watt. In SI (International System of Units) units, 1 V x A = 1 W. VA rating is most used for generators and transformers, and other power handling equipment, where loads can be reactive (inductive or capacitive).

Kilovolts constant potential – It means the potential in kilovolts of a constant potential generator. It also refers to a steady, unchanging voltage level, measured in kilovolts (thousands of volts), used in applications like X-ray imaging, where a constant electrical pressure is applied to accelerate electrons, ensuring consistent beam quality and image contrast, unlike fluctuating AC (alternating current) power. In essence, it is the precise, stable electrical potential (voltage) supplied by a generator to an X-ray tube, allowing for controlled production of X-ray photons.

Kilowatt hour – It is a measure of electrical energy. It consists of 1,000 watts of electricity used for one hour.

Kimberlite – It is a variety of peridotite which is the most common host rock of diamonds.

Kimberlite diatremes – These are carrot-shaped, volcanic pipes formed by explosive eruptions of deep-mantle kimberlite magma, bringing diamonds and mantle fragments to the surface. These are characterized by fragmented rock (breccia) with angular country rock and mantle pieces, forming crucial diamond-mining structures.

Kindling point – It is also called auto-ignition temperature. It is the lowest temperature at which a given substance spontaneously ignites in a normal atmosphere without an external source of ignition such as a flame or spark, i.e. when the ambient temperature is sufficiently high to provide the activation energy needed or combustion. Substances which spontaneously ignite at naturally occurring temperatures are termed pyrophoric.

Kinematic analysis – It is an analysis to determine the position, velocity, and acceleration of all bodies in a mechanical system at a sequence of user-specified time steps. This type of analysis is frequently used to check the range of motion and to determine whether the design will allow motion / velocity / acceleration to be in the expected range.

Kinematic assumption – It is a simplifying hypothesis about the motion or deformation (displacements, velocities) of a structure or body, used to analyze its behaviour without focusing on the forces causing it, frequently simplifying complex mechanics problems, such as the Bernoulli-Euler beam theory’s assumption that plane sections remain plane during bending. These assumptions define the geometric relationships and possible movements within a system, like a robotic arm or a collapsing bridge, to make calculations feasible.

Kinematic chain – It is an assembly of rigid bodies (links) connected by joints (pairs) which allows for constrained, relative motion, forming the basis of mechanisms like robot arms or car suspensions. It becomes a mechanism when one link is fixed, defining specific movement, and a machine when it performs work, with a classic example being the four-bar linkage or slider-crank system.

Kinematic determinacy – It is a term used in structural mechanics to describe a structure where material compatibility conditions alone can be used to calculate deflections. A kinematically determinate structure can be defined as a structure where, if it is possible to find nodal displacements compatible with member extensions, those nodal displacements are unique. The structure has no possible mechanisms, i.e. nodal displacements, compatible with zero member extensions, at least to a first-order approximation.

Kinematic error – It is the deviation between a machine’s actual motion (position and orientation) and its ideal, commanded motion, arising from imperfections in manufacturing, assembly, and component wear, manifesting as unwanted linear (positioning, straightness) and angular (roll, pitch, yaw) displacements. It is important for high-precision systems like machine tools.

Kinematic hardening – It refers to a type of strain hardening during plastic deformation where the initial yield surface translates in stress space without altering its shape or size, effectively capturing the Bauschinger effect.

Kinematic hardening hypothesis – It is a material hardening rule in plasticity theory which states which during plastic deformation, the yield surface translates as a rigid body in the stress space without changing its size or shape.

Kinematic hardening model – It describes how a material’s yield surface translates (shifts) in stress space without changing size or shape, capturing phenomena like the Bauschinger effect (easier yielding in the reverse direction after tension). This model is crucial for cyclic loading (fatigue, ratcheting), modeling metal plasticity by showing that work hardening in one direction reduces yield stress in the opposite direction, unlike isotropic hardening where the surface expands.

Kinematic hardening rule – It describes how a material’s yield surface translates (shifts) in stress space without changing size or shape, modeling the Bauschinger effect, where tension hardening leads to compression softening, capturing realistic cyclic plasticity by moving the yield surface’s centre in the direction of plastic flow, important for accurate simulation of material behaviour under complex loads.

Kinematic joint – It is a connection between two mechanical links which allows for specific relative motion (like rotation or sliding) while constraining other motions, forming the fundamental building block of mechanisms to create controlled movement, such as a hinge, pin, or cam follower. These joints define degrees of freedom, classifying them as lower pairs (surface contact, like a pin joint) or higher pairs (line / point contact, like a cam), necessary for analyzing and designing machines.

Kinematic model – It is a mathematical description of a mechanical system’s motion (position, velocity, acceleration) without considering the forces causing it, focusing purely on the geometry of links and joints, crucial for designing robots, mechanisms, and vehicles to understand their work-space and movement capabilities. It essentially defines how something moves (kinematics) versus why it moves (dynamics).

Kinematic pair – It is a connection between two machine elements (links) which allows for specific, constrained relative motion, forming the fundamental joint in a mechanism, like a hinge or a sliding joint, enabling controlled movement for tasks such as transmitting or modifying motion. These pairs are important for designing machines, as they dictate how components interact.

Kinematic relation – It defines the mathematical connection between the motion (positions, velocities, accelerations) of different parts in a mechanical system, or the link between an object’s displacement and its resulting internal deformation (strain), without considering the forces causing the motion, focusing purely on geometry and movement. These relationships describe how components move relative to each other, forming the basis for designing mechanisms, and analyzing structural movement.

Kinematic relationship – It defines how different parts of a mechanical system move and relate to each other geometrically, describing positions, velocities, and accelerations without considering the forces causing the motion, frequently expressed through mathematical equations linking joint movements (like robot arms) or displacements to strains in structures. Basically, it is the ‘geometry of motion’ for mechanisms, analyzing linkage movements, coordinate transformations, and motion constraints in systems like engines.

Kinematics – It describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the forces which cause them to move.

Kinematics of mechanisms – It studies the motion (position, velocity, acceleration) of machine parts without considering forces, focusing on the geometry of movement to design systems for specific motion requirements, contrasting with dynamics (forces). A mechanism is a key part of a machine, a linkage designed to transmit controlled motion from an input to an output, frequently using interconnected links and joints like sliders or pivots.

Kinematic tensors – These are mathematical objects in continuum mechanics which describe motion, deformation, and strain of materials, extending scalars and vectors to represent complex directional relationships, like the deformation tensor or rate-of-deformation tensors, necessary for formulating how points, shapes, and material configurations change over time without considering forces. They are multi-dimensional arrays (rank 2 tensors are 3×3 matrices) whose components transform specifically under coordinate changes, capturing directional dependence in motion analysis.

Kinematic viscosity – It is defined as the resistance of liquid to flow. It refers to the thickness of the oil and is determined by measuring the amount of time taken for a given oil to pass through an orifice of a specified size. It is the ratio of absolute viscosity to the specific gravity of the oil at the temperature at which the viscosity is measured. Its unit is ‘stokes’. For practical purposes, viscosity of petroleum oils is expressed in time in seconds taken by a given quantity of oil to flow through a standard capillary tube. It is expressed as Saybolt universal seconds at 40 deg C or at 100 deg C.

Kinematic wear marks – In ball bearings, it is a series of short curved marks on the surface of a bearing race because of the kinematic action of imbedded particles or asperities rolling and spinning at the ball or roller contact points. The length and curvature of these marks depend on the degree of spinning and on the distance from the spinning axis of the rolling element.

Kinetic calculation – It refers to determining the energy of motion (kinetic energy, KE = 1/2m xv square) for moving objects, or computationally analyzing reaction rates and system dynamics, frequently involving parameters like reaction rates, activation energy, or flow rates, using mathematical models and data analysis to understand system behaviour, crucial in fields like chemical processing, and dynamics.

Kinetic coefficient of friction (Mk) – It is the coefficient of friction under conditions of macroscopic relative motion between two bodies. It is a unitless ratio representing the resistance between two surfaces already in relative motion, calculated as the kinetic friction force (Fk) divided by the normal force (N) (Fk = Mk x N), and it is typically lower than the static coefficient since it takes less force to keep an object moving than to start it moving. This value depends on the materials and surface roughness, determining how ‘slippery’ moving parts are and is important for designing systems like engines, brakes, and conveyor belts.

Kinetic disintegration system (KDS) – It is an innovative grinder-dryer which uses the heat from mechanical grinding (comminution) and centrifugal force to simultaneously reduce particle size and extract moisture from wet materials (waste) into fine, dry powders, eliminating the need for separate drying steps, external heat, and reducing energy use. It turns wet waste into valuable, uniform, pathogen-free products like fertilizer or fuel feedstock.

Kinetic energy – The kinetic energy of an object is the energy which it possesses because of its motion. It is calculated by virtue of its mass and velocity and is equal to half its mass times its velocity squared Kinetic energy of atoms or molecules increases with temperature as the heat (energy) transferred into the substance is converted into kinetic energy with resulting increase in the velocities of the particles.

Kinetic energy density – It is the kinetic energy of a moving system (like a fluid or solid body) per unit of volume, representing the intensity of motion within a space, calculated using mass density (d) and velocity (v), basically 1/2d x v square, making it analogous to dynamic pressure and is important for analyzing fluid flow, impact, and material dynamics.

Kinetic energy index – It frequently refers to a performance metric for systems like flywheels, quantifying energy storage (KE = 1/2m x v square), while normally, ‘kinetic energy’ (KE) is the energy of motion, important for dynamic analysis in vehicles, fluid mechanics, and impacts, measured in Joules (J). Specific applications include calculating vehicle crash safety, analyzing wind / hydro power, and assessing material fracture in mining, showing kinetic energy’s importance in design and performance evaluation.

Kinetic energy recovery system – It captures a vehicle’s kinetic energy (energy of motion) normally lost during braking, stores it (in batteries or flywheels), and redeploys it as a power boost for acceleration, improving fuel efficiency and performance. Kinetic energy recovery systems convert kinetic energy into another form (electrical or mechanical) during deceleration, then back into mechanical power for propulsion when needed, chiefly applicable to road vehicles.

Kinetic equations – These are mathematical expressions which describe the evolution of distribution functions of particles in a plasma, determined self-consistently from their positions and velocities, particularly in the presence of electro-magnetic fields.

Kinetic exergy – It is the maximum useful work obtainable from the motion (velocity) of a system relative to the environment, basically its kinetic energy expressed as work potential relative to a ‘dead state’ (environmental equilibrium).

Kinetic expressions – These refer to mathematical formulations which describe the rates of chemical reactions and the relationships between different factors affecting these rates, such as pressure and concentration.

Kinetic friction – It is the friction under conditions of macroscopic relative motion between two bodies. This term is sometimes used as a synonym for kinetic coefficient of friction. However, it can also be used merely to indicate that the type of friction being indicated is associated with macroscopic motion rather than static conditions.

Kinetic friction coefficient (Mk) – It is a unitless ratio representing the resistance between two surfaces already in relative motion, calculated as the kinetic friction force (Fk) divided by the normal force (N) i.e., Mk = Fk/N, indicating how much force is needed to keep an object sliding. It is normally lower than the static coefficient since it takes more force to start motion than to maintain it, depending on material properties and surface roughness.

Kinetic hydrate inhibitors – These are water-soluble polymers which delay hydrate nucleation and initial crystal growth, preventing gas hydrate plugging in pipelines and ensuring the free flow of fluids. They function as either hydrate growth delay inhibitors or hydrate agglomeration inhibitors, with only small quantities needed for effective prevention of gas hydrate formation.

Kinetic inhibitors – These are water-soluble polymers which interact with hydrate nucleation processes to delay crystal growth, preventing gas hydrate plugging in pipelines. They act as hydrate growth delay inhibitors and agglomeration inhibitors, ensuring the free flow of fluids.

Kinetic model – It is a mathematical framework describing how a system’s components (reactants, particles) change over time, focusing on reaction rates, movement, and interactions, rather than just equilibrium states, to predict system behaviour like product yields, energy flow, and performance in reactors, important for optimizing processes in chemical, and physical systems. It combines reaction kinetics (speed of reactions) with fluid dynamics (hydrodynamics) for accuracy in real-world applications like gasification.

Kinetic parameter – It is a quantitative value which describes the rate or speed of a process or reaction, such as chemical reaction rate constants (k), or activation energy (Ea), used to model, optimize, and predict system performance, efficiency, and product yield in chemical, and materials engineering. These values are derived from experimental data and kinetic models, helping engineers to control how fast things happen, unlike thermodynamic parameters which describe feasibility.

Kinetic rate constant (k) – It is a crucial proportionality coefficient in reaction kinetics which quantifies how fast a reaction occurs, independent of reactant concentrations but highly dependent on temperature, pressure, and catalysts. It links the reaction rate to reactant concentrations and determines the reaction’s speed – a higher ‘k’ means a faster reaction, important for designing reactors, optimizing processes, and predicting system behaviour in chemical, and environment engineering.

Kinetics – it is also known as chemical kinetics or reaction kinetics. It is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a reaction occurs but in itself tells nothing about its rate.

Kinetics analysis – It studies the causes of motion, focusing on the relationship between forces, torques, and resulting movement or reaction rates, differentiating from kinematics (motion description) and used in several fields like chemical engineering (reaction rates) to understand why things move or change, optimizing design, performance, and understanding mechanisms.

Kinetic study – It is the systematic investigation of reaction rates (how fast processes occur) and the underlying mechanisms, analyzing factors like temperature, pressure, and concentration to develop models for reactor design, process optimization, and understanding complex chemical or physical transformations, important for everything from chemical plants to materials science.

Kinetic theory of gases – It defines a gas as countless tiny particles in constant, random motion, explaining macroscopic properties like pressure, temperature, and viscosity by their microscopic collisions, stating pressure comes from wall impacts, and linking average kinetic energy directly to absolute temperature, important for understanding gas dynamics, heat transfer, and material properties.

Kingpin – It is a critical pivot shaft in steering systems, allowing wheels to turn, or a robust pin on a semi-trailer which locks into a tractor’s fifth wheel, enabling articulation and load transfer between the tractor and trailer. It is a central component for vehicle motion, providing steering axis in cars and coupling in heavy vehicles, with its inclination influencing steering stability and self-centering.

King post – It is a central vertical post used in architectural or bridge designs, working in tension to support a beam below from a truss apex above, whereas a crown post, though visually similar, supports items above from the beam below.

King post truss – It is used for simple roof trusses and short-span bridges. It is the simplest form of truss in that it is constructed of the fewest truss members (individual lengths of wood or metal). The truss consists of two diagonal members that meet at the apex of the truss, one horizontal beam that serves to tie the bottom end of the diagonals together, and the king post which connects the apex to the horizontal beam below.

Kingsbury bearing – It is a pad bearing in which the pads are free to take up a position at an angle to the opposing surface according to the hydrodynamic pressure distribution over its surface.

Kink – It features local curvature of the same direction on adjacent sides of the sheet metal.

Kink band (deformation) – In polycrystalline materials, it is a volume of crystal which has rotated physically to accommodate differential deformation between adjoining parts of a grain while the band itself has deformed homogeneously. This occurs by regular bending of the slip lamellae along the boundaries of the band.

Kink banding – It is the localized formation of sharp, angular folds (kinks) within layered or crystalline materials, creating a distinct, deformed zone which accommodates stress, especially under compression, by tilting crystal planes or layers to a new orientation, leading to failure in composites or structural weakening in ropes and geological strata. It is a form of buckling or plastic deformation where a thin band abruptly changes orientation, marked by kink planes or boundaries.

Kinking – It is a temporary or permanent distortion of belting caused by doubling the belt on itself.

kinking angle – It is the angle at which a material’s internal structure (like layers or fibres in composites, or dislocations in crystals) deviates or rotates under stress, forming a localized band of shear deformation (a ‘kink band’) to accommodate compressive strain, frequently preceding fracture, and it is important in predicting failure in layered materials like composites and geological formations.

kip (Kilo-pound) – It is a unit of force equal to 1,000 pounds-force, mainly used in structural and civil engineering in some countries handle large loads more conveniently. It simplifies calculations for heavy forces in building, bridge design, and aerospace by avoiding large numbers of pounds, and is frequently expressed as ‘kip’ or ‘K’, sometimes as ‘kipf’ (kip-force) to distinguish it from mass.

Kirchhoff’s circuit laws – These are two equalities that deal with the current and potential difference (normally known as voltage) in the lumped element model of electrical circuits. These are widely used in electrical engineering. They are also called Kirchhoff’s rules or simply Kirchhoff’s laws. These laws can be applied in time and frequency domains and form the basis for network analysis. Both of Kirchhoff’s laws can be understood as corollaries of Maxwell’s equations in the low-frequency limit. They are accurate for direct current circuits, and for alternating current circuits at frequencies where the wave-lengths of electro-magnetic radiation are very large compared to the circuits.

Kirchhoff’s current law – This law states that the current entering any junction is equal to the current leaving that junction, i.e., i1 +i2 + i3 +i4, where ‘i’ is the current. This law, also called Kirchhoff’s first law, or Kirchhoff’s junction rule, states that, for any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node, or equivalently the algebraic sum of currents in a network of conductors meeting at a point is zero. Kirchhoff equations – In fluid dynamics, these equations describe the motion of a rigid body in an ideal fluid.

Kirchhoff hypothesis – It is also called Kirchhoff-Love theory. It simplifies thin plate analysis by assuming that straight lines normal (perpendicular) to the mid-surface of a plate remain straight and normal after deformation, meaning there’s no transverse shear deformation and thickness do not change, allowing for a 2D model for bending stresses and deflections. It is an extension of Euler-Bernoulli beam theory, important for structural mechanics, especially for thin structures where deflection is small relative to thickness.

Kirchhoff’s Laws – These are two fundamental rules for analyzing circuits. Kirchhoff’s current law states that current entering a junction equals current leaving (conservation of charge), while Kirchhoff’s voltage law says the sum of voltages (rises and drops) in any closed loop is zero (conservation of energy). These laws, also known as the junction and loop rules, are necessary for solving complex circuits where simple series / parallel analysis fails.

Kirchhoff-love plate theory – It is also called classical plate theory. It is a fundamental model for analyzing thin plates under transverse loads, assuming they remain thin and rigid perpendicular to their surface, meaning shear deformation is ignored, allowing prediction of deflections, stresses, and moments by reducing the 3D problem to a 2D analysis of mid-surface displacement. It is an extension of Euler-Bernoulli beam theory, ideal for thin structures, using key assumptions (like normals staying normal) to derive governing equations for bending.

Kirchhoff’s voltage law – This law states that the sum of all the voltages around a loop is equal to zero, i.e., v1 + v2 + v3 +v4 = 0, where ‘v’ is the voltage. This law, also called Kirchhoff’s second law, or Kirchhoff’s loop rule, states that the directed sum of the potential differences (voltages) around any closed loop is zero.

Kirkendall effect – It is a diffusional process that occurs at the interface of two materials with unequal diffusivities, resulting in void formation because of the faster diffusion of one material over the other, as observed in diffusion couples. This effect is characterized by the movement of the interface toward the faster-diffusing material and the compensation of material flow through vacancy diffusion. It is the motion of the interface between two metals which occurs because of the difference in diffusion rates of the metal atoms.

Kirkpatrick model -It is a 4-level framework for evaluating training effectiveness, assessing ‘reaction, learning, behaviour, and results, widely used in several fields to measure if a technical programme improved skills, changed job performance, and impacted organizational goals like efficiency or quality. It helps engineers and managers understand if training works, from participant satisfaction (Level 1) to concrete organizational outcomes (Level 4).

Kirsch equations – These are a set of formulas from elasticity theory which calculate stress and displacement around a circular hole (like a well-bore or tunnel) in an infinite, elastic, and homogeneous solid, revealing stress concentrations and distributions caused by far-field stresses and internal / external pressures. These equations are important in rock mechanics and petroleum engineering for analyzing well-bore stability and fracture initiation by determining radial and hoop stresses.

Kirsch solution – It is a classic elasticity solution describing stress changes around a circular hole in an infinite plate, used in geo-mechanics (like oil / gas drilling) to find stresses (radial, tangential, shear) around a well-bore by modeling far-field stresses, wellbore pressure, and pore pressure, assuming linear elastic, homogeneous, and isotropic rock.

Kirksite alloy – It is a specific zinc-aluminum alloy (around 94 % zinc, 6 % aluminum) mainly used for low-cost, low-volume tooling like dies for sheet metal forming, plastic moulding, and general non-stressed components, valued for its excellent fluidity, low melting point for accurate casting, machinability, and plating ability, offering a faster, cheaper alternative to steel tools for prototyping.

KIscc – It is the threshold stress intensity for stress corrosion cracking. It is abbreviation for the critical value of the plane strain stress-intensity factor which produces crack propagation by stress-corrosion cracking of a given material in a given environment.

Kish – It is the free graphite which forms in molten hyper-eutectic cast iron as it cools. In castings, the kish can segregate toward the cope surface, where it lodges at or immediately beneath the casting surface.

Kish graphite – It is a high-quality, naturally occurring flake graphite which forms as a by-product on the surface of molten iron during ironmaking, precipitating out as carbon atoms crystallize when the iron cools, frequently seen as light, flaky dust rising from the melt. Named from a German word for impurities, it is basically pure carbon, valuable for its crystalline structure, and can be recovered from industrial waste for use in batteries or advanced materials after purification.

Kiss cut – It is a form of die cutting where the top layer of material is cut without cutting through the bottom attached material.

Kissing (touching) – It consists of gating with minimum metal left at casting breakoff point, having a gate just ‘kiss’ the surface.

Kit drawing – It identifies an item or group of items with instructions for their use. It does not necessarily define a complete functional assembly. It is prepared when it is desired to identify all of the items required to perform a specific operation in kit form. It includes (i) a parts list of the contents of the kit including the identification of each item, (ii) documents which are a part of the kit, (iii) pictorial representations, (iv) special tool requirements for installation of the kit, and (v) retest or recalibration requirements.

Kjeldahl nitrogen – It is also known as Total Kjeldahl Nitrogen (TKN). It refers to the sum of nitrogen compounds present in organic substances, ammonia (NH3), and ammonium (NH4+) within a sample. This method is used to quantify the total nitrogen content in various materials like food, soil, water, and waste-water.

Kleingarn acid management system – By adopting this regeneration technology, the costs of replacement of the spent pickling liquors with new acid can be reduced. This technology needs less initial investment. Application of Kleingarn acid management system as regeneration method helps in reducing waste volume by saving the amount of hydrochloric acid being used. This regeneration method also can ease the recycling of acid wastes. Kleingarn acid management system not only needs less initial investment but at the same time it helps in reducing spent pickling liquor volume. Regeneration of spent pickling liquor using Kleingarn acid management system can assist in increasing the acid strength and reducing the iron concentration at the same time. Experiments are needed to be carried out in order to obtain the optimum pickle rate using this regeneration method. This regeneration process can be repeated until the dedicated hydrochloric acid bath tank needs to be emptied for cleaning or repair. Once the dedicated hydrochloric acid bath tank is emptied, fresh solution is to be made up using partly spent acid from other tanks plus fresh acid. The regeneration of hydrochloric acid using Kleingarn acid management system has ecological advantages.

Klemm colour etching – It is a metallographic technique which uses a controlled corrosion process to deposit a thin, colored sulfide-based film on a metal surface, revealing grain structure, phase composition, and other microstructural features.

K-lines – Once the photoelectric effect creates a vacancy in the K-shell, the excited state relaxes by filling the vacancy with an electron from an outer orbital. Only certain transitions are allowed because of quantum mechanical rules called selection rules. The transitions which follow the selection rules are termed allowed (diagram) lines, those that do not are called forbidden, and those that result in atoms with two or more vacancies in inner orbitals at the time of the emission are called satellite (non-diagram) lines. The number of K-lines, and the exact one observed for an element, depends in part on the number of filled orbitals.

Klink – It is the internal crack which frequently opens transversely upon further reductions. Klink is formed since the rapid heating of larger sections results in differential expansion which can locally exceed the tensile strength of the interior of the section.

Klinkenberg correction – It is a petro-physical method to adjust gas permeability measurements in porous rocks to find the rock’s true liquid permeability, accounting for the ‘gas slippage effect’ where gas molecules slip along pore walls, causing over-estimation. This effect occurs since gas, unlike liquids, does not stick to surfaces, leading to higher apparent flow rates in small pores (like in low-permeability shales), so the correction extrapolates to infinite pressure (no slip) to find intrinsic permeability.

Klinkenberg effect – It describes how gas flows more easily through porous media (like rock) than liquids, because of the gas molecules ‘slipping’ along pore walls, especially in small pores, boosting flow and making gas permeability seem higher than liquid permeability. This ‘slip flow’ happens when the gas’s mean free path approaches pore size, reducing resistance and increasing gas flow rate, needing corrections (Klinkenberg correction) to estimate the true permeability (absolute permeability) from gas measurements, particularly at low pressures and in low-permeability materials.

Klinkenberg permeability – It is the equivalent liquid permeability of a porous rock, found by correcting gas permeability measurements for the ‘gas slippage’ (Klinkenberg effect) which occurs at low pressures, where gas molecules slip along pore walls, over-estimating permeability compared to liquid flow. It is determined by plotting measured gas permeability against the inverse of mean pressure and extrapolating to infinite pressure, yielding a value closer to true absolute permeability (like with water).

Klystron – It is a specialized linear-beam vacuum tube which is used as an amplifier for high radio frequencies, from ultra-high frequency up into the microwave range. It is an evacuated electron-beam tube in which an initial velocity modulation imparted to electrons in the beam subsequently results in density modulation of the beam. This device is used as an amplifier or oscillator in the microwave region.

K-mass – It is an epoxy-based intumescent coating to provide fire protection. It works by endothermic reaction rather than insulation.

Knapsack problem – It is an optimization problem in combinatorial optimization which involves the optimal assignment of items to a single knapsack, where the objective is to maximize the total value without exceeding the knapsack’s capacity. It encompasses different types, including binary, subset sum, bounded, and unbounded knapsack problems, as well as those with special constraints. It derives its name from the problem faced by someone who is constrained by a fixed-size knapsack and is required to fill it with the most valuable items. The problem frequently arises in resource allocation where the decision-makers have to choose from a set of non-divisible projects or tasks under a fixed budget or time constraint, respectively.

Kneading – It is the process of mixing water with blended clay (clay with additional minerals) to make it plastic. Kneading of the brick earth occurs after clay has been weathered, and blended and is the last step in the preparation of brick earth before moulding it into the shape.

Knee braces These are braces which are strategically angled against other structural supports to provide vertical stabilization for conveyors. Regular checks are necessary for maintaining the angular stability and structural integrity of knee braces.

Knife coating – It is a method of coating a substrate (normally paper or fabric) in which the substrate, in the form of a continuous moving web, is coated with a material, the thickness of which is controlled by an adjustable knife or bar set at a suitable angle to the substrate.

Knife edge conveyor belt – It is an innovative conveyor belt design featuring an ultra-thin, sharp edge crafted for the seamless transfer of small or delicate items. Regular evaluations are vital to preserve the sharpness and overall integrity of the knife edge.

Knife gate valve – A knife gate valve works by lifting a plate with a planar or ‘knife’ edge from the path of flow which can literally cut through different impediments during closing thereby creating complete closure against a soft sealing surface. This soft sealing surface normally dictates use in rather low-pressure systems and is not designed to handle high pressure. The knife gate valve is primarily designed for isolation or on / off service rather than a throttled or partial-flow application.

Knife-line attack – It is the inter-granular corrosion of an alloy, normally stabilized stainless steel, along a line adjoining or in contact with a weld after heating into the sensitization temperature range.

Knife mark – It is a continuous scratch (which also can be creased) near a slit edge, caused by sheet contacting the slitter knife.

Knife valves – These valves are used in systems which deal with slurries or powders. They are mainly used for on and off purposes; whether or not the slurry or powder flows or not. A knife gate valve can be used for fibrous material because it can cut through to close the valve.

Knitted fabric composite – It is a high-performance material combining a 3D knitted textile structure (using fibres like glass, carbon, or aramid) with a binding matrix (like thermoset or thermoplastic polymers) to create a strong, lightweight, and frequently flexible material with tailored properties for demanding applications, offering design flexibility and efficiency over traditional woven composites.

Knitted fabrics – In composites, these are the fabrics produced by inter-looping chains of yarn.

Knock – In a spark ignition engine, It is the uneven burning of the air / fuel charge which causes violent, explosive combustion and an audible metallic hammering noise. Knock results from premature ignition of the last part of the charge to burn.

Knock-down – It consists of a collection of parts / sub-assemblies of an equipment which are required to be assembled at the site where the equipment is to be installed and commissioned. The parts are typically manufactured at the manufacturing plant, and then sent to the erection site for final assembly.

Knock-down factor – It is a reduction factor used in engineering, particularly for thin-walled structures to account for the substantial drop between theoretically predicted strength (like buckling load from linear analysis) and actual experimentally observed strength, mainly because of the imperfections (geometric deviations, material variations). It is normally the ratio of the actual or experimental load to the theoretical load, helping designers create safer structures by applying a conservative multiplier to ideal calculations.

Knock-off riser – It is the riser with a small attachment and can be knocked off with a hammer.

Knock-on effect – It is also known as ripple / domino effect. It describes the unintended, cascading, or secondary consequences which occur in one part of a complex system because of a change or event in another part, leading to further changes which can propagate or amplify, impacting overall performance, safety, or cost. These effects highlight the inter-connectedness of components, where a modification (e.g., material change, design tweak) triggers a chain reaction, sometimes beneficial but frequently detrimental, requiring careful analysis, frequently through methods like HAZOP (Hazard and Operability).

Knock-out – It is the removal of sand cores from a casting. It is also the jarring of an investment casting mould to remove the casting and investment from the flask. It is a mechanism for freeing formed parts from a die used for stamping, blanking, drawing, forging, or heading operations. It is also a partially pierced hole in a sheet metal part, where the slug remains in the hole and can be forced out by hand if a hole is needed. Knock-out is also means ejecting of a compact from a die cavity.

Knock-out drum – It is a pressure vessel in industrial plants which separates liquids (oil, water) from gas or vapour streams, frequently before they go to a flare system, compressor, or turbine. It works by slowing down the gas flow, allowing heavier liquid droplets to fall out by gravity, preventing damage to downstream equipment and ensuring safe, efficient flare operation by removing hazardous liquid carryover.

Knock-out mark – It is a small protrusion, such as a button or ring of flash, resulting from depression of the knockout pin from the forging pressure or the entrance of metal between the knockout pin and the die.

Knock-out pin – It is a power-operated plunger installed in a die to aid removal of the finished forging.

Knock-out punch – It is a punch which is used for the ejection of compacts.

Knock phenomenon – It is abnormal combustion in an engine where parts of the fuel-air mixture auto-ignite prematurely, creating uncontrolled pressure spikes and a distinct metallic ‘pinging’ sound, potentially causing severe engine damage. Instead of a smooth flame front from the spark plug, pockets of fuel explode independently, leading to high-frequency pressure oscillations and harmful effects like power loss and component failure.

Knock quality – It defines a fuel’s resistance to premature ignition (auto-ignition) in a spark-ignition engine, preventing the damaging, metallic ‘pinging’ sound (knocking / detonation) from uncontrolled explosions in the cylinder, and is measured by octane rating, with higher numbers indicating better knock quality and improved engine efficiency. Good knock quality allows for higher compression ratios, boosting power and efficiency, while poor quality leads to performance loss and potential engine damage.

Knoevenagel condensation – It is defined as a reaction involving the condensation of aldehydes or ketones with a compound to form arylidene derivatives, typically facilitated by conditions which include the presence of a base and specific solvents.  Knoevenagel condensation is a very important transformation in organic synthesis and is widely used for carbon–carbon bond formation. It has been used for the synthesis of important chemical intermediates, and polymers. This reaction is normally catalyzed by a base, an acid, or a heterogeneous neutral support.

Knoop hardness number (HK) – It is a number related to the applied load and to the projected area of the permanent impression made by a rhombic-based pyramidal diamond indenter having included edge angles of 172-degree 30-minute and 130-degree 0-minute computed from the equation ‘HK = P/0.072089d square’, where ‘P’ is the applied load, kgf, and ‘d’ is the length of the long diagonal of the impression in millimeters. In reporting Knoop hardness numbers, the test load is stated.

Knoop hardness test – It is an indentation hardness test using calibrated machines to force a rhombic-based pyramidal diamond indenter having specified edge angles, under specified conditions, into the surface of the material under test and to measure the long diagonal after removal of the load.

Knots per hour (KPH) – It is a distinctive unit of measurement indicating the conveyor system’s speed in terms of knots, demanding precise calculations and adjustments to fine-tune and optimize conveyor performance.

Knowledge – It can be defined as (i) awareness or familiarity gained by experience (of a person, fact, or thing), (ii) a person’s range of information which can be either a theoretical or practical understanding of a subject, language, etc. or the sum of what is known or both, and (iii) true, justified belief which means certain understanding, as opposed to opinion. Knowledge is the key resource, for the organizational strength. It is fundamentally different from the other traditional key resources such as land, labour, and even capital. The organization needs systematic work on the quality of knowledge and the productivity of knowledge. The performance capacity, if not the survival, of the organization in the knowledge society has become increasingly dependent on these two factors related to knowledge.

Knowledge base – It is a collection of formulas, rules, and lessons learned that, when connected to a computerized database and manipulated with artificial intelligence methods, allows decisions to be made which approximate those made by humans, but much faster.

Knowledge-based engineering – It is an engineering approach which captures and embeds product design knowledge (rules, algorithms, data) into software systems to automate and reuse complex design processes, allowing for the rapid generation of new, similar products from new specifications, hence boosting efficiency, consistency, and innovation in industries. It integrates CAD (computer-aided design), AI (artificial intelligence), and object-oriented programming, making CAD models ‘intelligent’ by including product understanding and process logic, not just geometry.

Knowledge-based expert systems – These are the most common types of knowledge-based systems. These systems mimic human experts’ decision-making processes, making them helpful for complex analyses, calculations and predictions. In addition to presenting solutions, they provide specific explanations for the problems which they are solving.

Knowledge-based system (KBS) – It is a computer programme which reasons and uses a knowledge base to solve complex problems. The term can refer to a broad range of systems. However, all knowledge-based systems have two defining components namely (i) an attempt to represent knowledge explicitly, called a knowledge base, and (ii) a reasoning system which allows them to derive new knowledge, known as an inference engine.

Knowledge engineer – Knowledge engineer is a professional engaged in the science of building advanced logic into computer systems in order to try to simulate human decision-making and high-level cognitive tasks. A knowledge engineer supplies some or all of the ‘knowledge’ which is eventually built into the technology.

Knowledge engineering – It is the engineering process of creating the knowledge bases, involving knowledge acquisition, representation, and validation, making it a core part of artificial intelligence.

Knowledge integration – It refers to the process of merging two or more originally unrelated knowledge structures into a single structure.

Knowledge management – It is simply defined as doing what is needed to get the most out of knowledge resources. It focuses on organizing and making available important knowledge, wherever and whenever it is needed. It is all about the application of the available knowledge in the organization in different situations faced during its functioning. It is the organizational discipline which promotes an integrated approach to the creation, capture, organization, access and use of the organizational knowledge assets. These assets include structured databases, textual information such as policy and procedure documents, and most importantly, the tacit knowledge and expertise resident in the heads of individual employees. Knowledge management is the systematic management of the organizational knowledge assets for creating value and meeting its tactical and strategic requirements. It consists of the initiatives, processes, strategies, and systems which sustain and enhance the storage, assessment, sharing, refinement, and creation of knowledge. The organization is needed to define knowledge management in terms of its objectives. It is the activity which is being practiced by several organizations all over the world. In the process of knowledge management, the organizations comprehensively gather information by using numerous methods and tools. The gathered information is then organized, stored, shared, and analyzed using defined techniques. The analysis of such information is done based on resources, documents, people, and their skills. Properly analyzed information is then stored as ‘knowledge’ of the organization. This knowledge is later used for activities such as organizational decision making and training new employees etc.

Knowledge management cycle – It is a process of transforming information into knowledge within the organization. It constitutes as a continuous cycle of three processes, namely (i) knowledge creation and improvement, (ii) knowledge distribution and circulation, and (iii) knowledge addition and application. The knowledge management cycle explains how knowledge is captured, processed, and distributed in the organization. It is the deliberate and systematic collaboration of the organizational human resource, technologies, and processes. It is styled and structured in order to add value through reuse and innovation.

Knowledge management system – It expresses a deliberate, systematic and synchronized approach to ensure the full utilization of the organizational knowledge base, combined with the potential of employees’ skills, competencies, thoughts, innovations, and ideas to create a more efficient and effective organization. It incorporates both holding and storing of the knowledge perspective, with respect to the intellectual assets. It has four sub-systems consisting of (i) knowledge discovery system, (ii) knowledge capture system, (iii) knowledge sharing system, and (iv) knowledge application system.

Knowledge plane – It is the component in knowledge-defined net-working responsible for modeling network behaviour and decision-making, utilizing machine learning algorithms to create knowledge which informs actions related to resource management, network configurations, and other applications.

Knowledge, skills, and abilities – They define the essential attributes needed for job performance. Knowledge is what the person knows (facts, information, theory), skills are what the person does (learned tasks, like coding or speaking a language), and abilities are the capacity of the person to do something (natural aptitudes, like problem-solving or critical thinking). Employers use knowledge, skills, and abilities to evaluate if a candidate has the right mix of understanding, practical proficiency, and inherent talent for a role, frequently detailed in job descriptions or application papers.

Knowledge structure – It is the organized, interconnected system of facts, concepts, procedures, and strategies which experts use, representing how knowledge elements (like ideas, rules, or components) are arranged, linked, and applied to solve problems, moving from basic facts to complex theories (e.g., Ohm’s Law integrating multiple concepts). These structures are important for building expertise in fields like structural engineering (material properties, load resistance) and are modeled in ‘knowledge-based engineering’ (KBE) for intelligent systems, using representations like frames or scripts for complex situations.

Known data – It refers to factual information or raw facts (like numbers, text, symbols) which are collected, organized, and understood within a specific context, serving as the foundation for reasoning, analysis, and decision-making, transforming into meaningful ‘information’ once processed and interpreted, and frequently categorized as quantitative (numerical) or qualitative (descriptive).

Known deposit – It is also called known source. It is a deposit or source which has been demonstrated to exist by direct evidence. More detailed specifications can be found in relevant source-specific aligned systems.

Known source – It is also called known deposit for minerals. It refers to one where the existence of a substantial quantity of recoverable material or energy has been demonstrated by direct evidence.

Known technological options – These are technologies which exist in operation or pilot plant stage to-date is known as known technological options. It does not include any new technologies which needs drastic technological breakthroughs.

Knuckle area – It is the area of transition between sections of different geometry in a filament- wound part, e.g., where the skirt joins the cylinder of the pressure vessel. It is also called Y-joint.

Knuckle joint – It is a type of pin joint designed to connect components which are predominantly under tensile load, though they can handle compressive loads if guided. The main function is to provide a flexible link which accommodates slight misalignment and pivoting motion, without transmitting torque. It is a mechanical joint that connects two rods or pipes at an angle, allowing limited angular movement and rotation between them. It consists of a spherical ball and socket joint, with a cylindrical extension called the knuckle.

Knuckle-joint drive system – It refers to a mechanical assembly which connects two rods or links to mainly transmit axial tensile force, while allowing for a limited quantity of angular movement (pivoting in a single plane) between them. It is also normally used in press machines to generate high force.

Knuckle-joint press – It is a press whose action is based on a hinged joint and flywheel. This type of press has a relatively long extrusion dwell, particularly useful for preventing the springing back of the surface metal. Knuckle-joint presses are available with press forces from 2,000 kilonewton to 10,000 kilonewton and bolster widths from 1,500 millimeters to 4,000 millimeters, fixed or adjustable stroke.

Knuckle-lever press – It is a heavy short-stroke press in which the slide is directly actuated by a single toggle joint which is opened and closed by a connection and crack. It is used for embossing, coining, sizing, heading, swaging, and extruding.

Knuckle / stadium brick – Knuckle / stadium brick is required to have good resistance to molten metal erosion and thermal shock.

Knudsen absolute manometer – It is an instrument to measure absolute pressures.

Knudsen diffusion – It is a type of gas transport in porous materials where molecules predominantly collide with the pore walls rather than with each other, occurring when the pore size is comparable to or smaller than the gas’s mean free path. This mechanism becomes dominant at low pressures or in fine pores (e.g., less than 50 nano-meters), making wall collisions the main factor determining the diffusion rate, unlike bulk diffusion, which relies on gas-gas collisions.

Knudsen diffusion coefficient (Dk) – It quantifies gas transport in porous media when molecules collide more with pore walls than with each other, occurring when the mean free path (lambda) is larger than the pore diameter (d) (high Knudsen number, Kn = lambda/d is higher than 1. It is calculated using kinetic theory, relating pore size, temperature, and molecular properties for straight pores, describing diffusion in rarefied conditions.

Knudsen effect – It describes gas transport (diffusion or flow) in porous materials or narrow channels where the mean free path (MFP) of gas molecules becomes comparable to or larger than the pore or channel dimensions, causing molecules to collide more with the walls than with each other, altering flow behaviour and frequently reducing overall gas flux or thermal conductivity. It is substantial in low-pressure conditions or microporous media, characterized by the Knudsen number (Kn is less than 0.1), where traditional continuum flow breaks down and molecular interactions with boundaries dominate.

Knudsen equation – It describes gas flow in the free molecular flow regime (Knudsen number less than 1), where molecules collide more with channel walls than each other, dominating mass transfer, especially in micro-channels / nano-channels or high vacuum. It relates gas flux (flow rate) to pressure difference, temperature, and tube dimensions, frequently using the Knudsen diffusion coefficient (Dik) for transport through pores. It is a key concept for understanding gas dynamics in rarefied conditions, contrasting with continuum flow.

Knudsen flow – It describes the movement of fluids with a Knudsen number near unity, that is, where the characteristic length in the flow space is of the same order of magnitude as the mean free path. Depending on the source there is a range mentioned of 0.1 is less than ‘Kn’ is less than 10 for which Knudsen flow occurs. Knudsen flow is the transitional range between viscous flow and molecular flow. It is prevalent in the medium vacuum range.

Knudsen layer – It is a thin, non-equilibrium region near a solid or liquid surface where gas molecules transition from their surface interactions to bulk fluid behaviour, characterized by gas-surface collisions dominating over inter-molecular collisions, leading to an anisotropic velocity distribution at the surface becoming more isotropic further away. It is important in micro-scale / nano-scale flows and evaporation, acting as a kinetic boundary layer where continuum flow assumptions break down and rneed specialized modeling.

Knudsen number (Kn) – It is a dimensionless quantity in fluid dynamics representing the ratio of a gas’s mean free path (average distance between molecular collisions, lambda) to a characteristic length scale (L), used to determine if a fluid can be treated as a continuous medium or needs kinetic theory. A small Kn (e.g., less than 0.01) means frequent collisions, validating the continuum assumption (Navier-Stokes equations), while a large Kn indicates rarefied flow (slip flow, transition flow, free-molecule flow) where individual molecule behaviour matters.

Knudsen separation – It is a gas separation method which exploits differences in molecular weight by passing gas mixtures through porous membranes with extremely small pores, where gas molecules collide more with the pore walls than with each other, allowing lighter molecules (like hydrogen) to pass through faster, a principle used in isotope separation (like uranium) and hydrogen purification.

Knurling – It is impressing a design into a metallic surface, normally by means of small, hard rollers which carry the corresponding design on their surfaces.

Knurling tool – It is a machining tool with patterned, hardened rollers used on lathes to press a texture (like diamond, straight, or diagonal lines) onto a rotating work-piece, creating raised ridges for improved grip, aesthetics, or to secure press-fit components without cutting the metal. The tool’s wheels deform the material (cold forming) rather than removing it, adding texture for better traction on handles (like hammers, bar-bells) or decorative finishes.

Knurl thumb adjustable nut – It is a specialized nut designed for accumulating conveyors, allowing tool-free adjustments to the pressure required for product movement. Regular checks ensure optimal functionality and pressure settings.

Kobayashi – It refers to a commonly used multistep model in pyrolysis which consists of two competing reactions, which convert coal into char and volatiles at different temperature levels, allowing for varied final volatile yields.

K-OBM (Kassel-OBM) converter – It is a type of steelmaking technology which uses a combination of top and bottom blowing oxygen to refine molten iron and produce steel. The K-OBM process improves bath mixing and metallurgical reactions, resulting in cleaner steel with fewer inclusions and impurities compared to traditional basic oxygen furnace (BOF) converters.

Kobetsu Kaizen – It is a Japanese term meaning ‘focused improvement’ or ‘targeted improvement’. It is a core pillar of ‘total productive maintenance’ (TPM) where small, cross-functional teams target and eliminate specific losses (like break-downs, defects, or delays) in a particular machine or process to achieve rapid, substantial gains in productivity and ‘overall equipment effectiveness’ (OEE). It involves systematic problem-solving, analysis (like failure analysis), and implementing small changes to create big results, frequently focusing on achieving ‘zero losses’ (break-downs, defects, and accidents).

K-OBM-S process – It has been developed by Voest Alpine Industrieanlagenbau (VAI) and evolved from Kawasaki’s K-BOP process. The K-OBM-S process initiated with tuyeres installed in the converter bottom. However, two installations are side-blown reactors. Hence, a K-OBM-S converter is top-blown with a lance and bottom or side blown with tuyeres. It is very similar to a modern AOD. However, in the K-OBM-S process, hydrocarbons, such as natural gas or propane, are used for tuyere protection and this can be helpful in increasing the refractory life.

Kocks mechanical analysis – It is also known as the Kocks–Mecking approach or Kocks–Mecking–Estrin model. It is a dislocation density-based constitutive modeling framework used to describe the strain hardening behaviour of crystalline materials, particularly metals and alloys. It links the macroscopic mechanical behaviour (stress-strain curves) to the evolution of the underlying micro-structure at a microscopic level.

Kocks-Mecking analysis – It is a dislocation-based model used to understand and predict metal work hardening (strength increase during deformation) by relating flow stress to dislocation density, considering both dislocation generation (hardening) and recovery (softening) processes, frequently visualized through Kocks-Mecking plots (strain hardening rate against stress) to characterize material behaviour for design.

Kocks-Mecking mechanical model – It is a widely used, physically-based constitutive model which describes the strain hardening behaviour of crystalline materials, mainly metals and alloys. It relates the material’s flow stress to the evolution of its internal micro-structure, specifically the average dislocation density.

Kohn–Sham equations – These are defined as a set of equations which allow the electron density function of a multi-particle system to be derived from a single-particle wave equation, transforming the problem of ground state eigenvalues of a multi-electron system into a single-electron problem. They express the electron density as the sum of the squares of single electron wave functions and are solved self-consistently through an iterative process.

Kohn-Sham orbitals – These refer to the independent orbital contributions used to decompose the ground-state density of an interacting electron system, represented as a sum of orthonormal orbitals, ensuring that the total density matches that of a fictitious system of non-interacting electrons.

Kolmogorov equations – These are a set of partial differential equations which describe the evolution of probabilities in continuous-time Markov processes, fundamental to understanding random systems. They come in two main forms: the ‘forward equation’ (similar to the Fokker-Planck equation) which tracks how the probability distribution of the process changes over time, and the ‘backward equation’ which describes the expected future behaviour from a given state. These equations are important for modeling dynamic systems with inherent randomness.

Kolmogorov length scale (n) – It defines the smallest eddies in a turbulent flow, representing the size where viscous forces convert turbulent kinetic energy into heat, calculated as n = (v cube/e) to the power 1/4, with ‘v’ being kinematic viscosity and ‘e’ the energy dissipation rate, marking the transition to isotropic, dissipative scales.

Kolmogorov scale – It defines the smallest universal length, time, and velocity scales in turbulent fluid flow, representing the point where viscous forces dominate and turbulent kinetic energy is converted into heat, marking the end of the energy cascade from large eddies to small ones. These scales, denoted by n (length), tk (time), and vk (velocity), are determined by the fluid’s kinematic viscosity (v) and the energy dissipation rate (e).

Kolmogorov-Smirnov test – It is a statistical method for testing the hypothesis that two independent groups have identical distributions, utilizing the maximum absolute difference between their empirical distribution functions. It allows for exact control over the Type I error probability under random sampling conditions.

Kondo effect – It refers to the screening of localized spins by surrounding conducting electrons, leading to an increase in electrical conductance at low temperatures in materials doped with magnetic impurities.

Kondo model – It is sometimes referred to as the s-d model. It is a model for a single localized quantum impurity coupled to a large reservoir of delocalized and noninteracting electrons. The quantum impurity is represented by a spin-1/2 particle, and is coupled to a continuous band of noninteracting electrons by an anti-ferromagnetic exchange coupling J. The Kondo model is used as a model for metals containing magnetic impurities, as well as quantum dot systems.

Konimeter – It is also called Koniscope. It is a device used for assessing airborne dust concentration, especially in mines or industrial settings, by drawing air over a greased glass slide where particles collect, allowing for microscopic counting to estimate dust levels and assess occupational health risks like silicosis. Basically, it is a portable air sampler for quantifying harmful particulate matter in a work-space, though largely superseded by more advanced methods.

Kozeny constant – It is a dimensionless coefficient used in the Kozeny–Karman formula to describe the permeability of porous media, typically approximated to be around five for different particle structures and porosities.

Kozeny equation – It is a mathematical model which describes permeability in a porous medium, derived from a capillary bundle model involving capillaries with a range of radii. It serves as a foundational equation for understanding fluid flow through porous materials.

K-radiation – It is the characteristics X-rays produced by an atom when a vacancy in the K-shell is filled by one of the outer electrons.

Krafft point – It is also called Krafft temperature. It is the minimum temperature for ionic surfactants where their solubility sharply increases, allowing them to form micelles since the temperature is high enough for crystals to dissolve into monomers, reaching the ‘critical micelle concentration’ (CMC). Below this point, surfactants remain mostly crystalline solids, while above it, they readily form micelles, making them effective surfactants in solution.

Kraft lignin – It is the complex aromatic polymer separated as a major by-product during the Kraft pulping process (or sulphate process) used to make paper, historically burned for energy but increasingly seen as a valuable, renewable feedstock for sustainable chemicals, resins, and carbon materials because of its phenylpropane structure and reactive functional groups. It is extracted from ‘black liquor’ and differs structurally from natural lignin because of extensive chemical modification, fragmentation, and cross-linking during the harsh pulping conditions.

Kraft process – It is a wood-pulping process in which sodium sulphate is used in the caustic soda pulp-digestion liquor. It is also called kraft pulping or sulphate pulping.

Kraft pulping process – It engages in the removal of lignin from wood chips using a mixture of alkaline cooking chemicals, sodium hydro-oxide and sodium sulphide, known as white liquor. Following the delignification process, a resultant weak black liquor containing degraded lignin, oxidized inorganic compounds (sodium sulphate and sodium carbonate), organic materials and white liquor (sodium sulphide and sodium hydro-oxide), is pumped to the chemical recovery cycle. Its solids content is increased in evaporators to elevate its heat value before feeding it to the recovery boiler. The organic constituents of the concentrated black liquor are combusted and the sodium sulphate is reduced to sodium sulphide. As a result, an additional quantity of sodium sulphate is added to the black liquor to compensate for its loss, hence the term ‘kraft (sulphate) pulping process’. The heat from the combusted organic constituents of the black liquor produces an inorganic smelt enriched by sodium sulphide and sodium carbonate (known as green liquor, GL) in the recovery boiler. In the dissolving tank, the smelt is treated with a weak white liquor solution, forming the green liquor dregs sludge in which the solid, undissolved particles are known as dregs. The dissolved sodium carbonate content (GL) of the sludge is diverted back into the kraft pulping cycle and is converted to sodium hydro-oxide in the causticizing process.

Kriging interpolation technique – It is a statistical method which provides optimal attribute interpolations by utilizing a good variogram model, allowing for flexibility in the selection of appropriate interpolation techniques based on the natural attribute distribution. It also enables the assessment of interpolation accuracy and the derivation of confidence intervals for attribute values.

Kriging model – It is an unbiased estimation method used to predict the response values of unknown samples and their uncertainty, normally applied in surrogate-model optimization algorithms and engineering optimization. It combines a known global approximation function with a random process characterized by a mean of zero and a defined covariance structure.

Kritzinger – It refers to a classification system for digital twins, which categorizes them into three types—digital models, digital shadows, and digital twins—based on the directionality of data flow between virtual and physical representations.

Kroll process – It is a process for the production of metallic titanium sponge by the reduction of titanium tetra-chloride with a more active metal, such as magnesium or sodium. The sponge is further processed to granules or powder.

Krupp combined blowing-stainless (KCB-S) process – The production of stainless steels in the BOF converter using the top lance has been practiced prior to the arrival of the AOD process. After introduction of the AOD (argon-oxygen decarburization) process, Krupp Stahl AG modified the converter at its Bochum works so that combined blowing through the lance and tuyeres can be practiced for refining stainless steels. The process has been named Krupp combined blowing-stainless or KCB-S process. The simultaneous introduction of process gases helped in the increase of the decarburization rate. The blowing through a top lance and through the tuyeres below the bath surface helped in achieving very high decarburization rates. The increased decarburization rate has led to a reduction of up to 30 % in the refining time compared to a conventional AOD alone. Liquid steel from an EAF is charged to the converter. At the start of the blow, pure oxygen is injected simultaneously through the lance and side-wall tuyeres. After a desired process temperature is reached, different additions are made during the blow. The additions consist of calcined lime, ferro-alloys, and scrap. After a critical carbon level is reached, the oxygen content of the process gas is reduced by using inert gases such as nitrogen or argon. Oxygen to inert gas ratios of 4:1, 2:1, 1:1, 1:2 and 1:4 is used as decarburization to lower levels is pursued. When the carbon content of 0.15 % is reached, the use of the lance is discontinued and the process gases are introduced only through the tuyeres. When the desired aim carbon level is reached, the oxygen blow is discontinued and silicon is added as ferro-silicon to reduce the chromium oxide in the slag and to achieve the needed silicon specification level. The addition of calcined lime and other fluxing agents with the ferro-silicon leads to the lowering of the dissolved oxygen content and improves the desulphurization.

Krypton – It is a chemical element; it has symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace quantities in the atmosphere and is frequently used with other rare gases in fluorescent lamps. Krypton is chemically inert. Krypton, like the other noble gases, is used in lighting and photography.

K-series – It is the set of X-ray wave-lengths comprising K-radiation.

K-shell – It is the innermost shell of electrons which surrounds an atomic nucleus and constitutes the lowest available energy level of the electrons. It has electrons which are characterized by the principal quantum number 1.

ksi – It stands for kilo-pound per square inch. It is a unit of pressure or stress, equaling 1,000 psi (pounds per square inch). It is normally used to measure tensile strength and other material properties, especially for metals, providing a larger, more manageable number than psi for high-strength materials. For conversion, 1 ksi is around 6.895 mega-pascals (MPa).

KTB process – Additional developmental work on K-BOP process has led to a smelting reduction process for stainless steelmaking using separate reactors. In the KTB process, final decarburization (below 0.1 % C) is carried out in a top-blown RH (Ruhrstahl-Heraeus) degassing unit.

Ku-band – It is a microwave frequency range (12 giga-hertz to18 giga-hertz) used mainly for satellite communication, named ‘K-under’ for being below the K-band, and is key for ‘direct-to-home’ (DTH) television, and very-small-aperture terminals, offering smaller dishes but suffering from rain fade more than lower bands, needing careful link design.

Kurdjumov-Sachs (K-S) correspondence -It is a specific crystallographic orientation relationship observed between the parent austenite (face-centered cubic, FCC) phase and the product martensite or ferrite (body-centered cubic / body centered tetragonal, BCC/BCT) phase in steels and other alloys during displacive phase transformations.

Kurdjumov-Sachs orientation relationship – It defines a specific atomic alignment between a face-centered cubic (fcc) parent phase (like austenite) and a body-centered cubic (bcc) product phase (like ferrite) during solid-state transformations, most notably in steels, where a {111}fcc plane becomes parallel to a {110}bcc plane, and a specific <110>fcc direction aligns with a <111>bcc direction, minimizing interface energy and allowing for easier atomic matching.

Kyanite -It is a typically blue alumino-silicate mineral, found in aluminium-rich metamorphic pegmatites and sedimentary rock. It is the high-pressure polymorph of andalusite and sillimanite, and the presence of kyanite in metamorphic rocks generally indicates metamorphism deep in the earth’s crust. Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction.

Kyoto mechanisms – The three Kyoto mechanisms are (i) clean development mechanism (CDM), (ii) joint implementation (JI), and (iii) emissions trading (ET). Kyoto mechanisms (i) stimulate sustainable development through technology transfer and investment, (ii) help countries with Kyoto commitments to meet their targets by reducing emissions or removing carbon from the atmosphere in other countries in a cost-effective way, and (iii) encourage the private sector and developing countries to contribute to emission reduction efforts. Clean development mechanism and joint implementation are the two project-based mechanisms which feed the carbon market. Clean development mechanism involves investment in emission reduction or removal enhancement projects in developing countries which contribute to their sustainable development, while joint implementation enables developed countries to carry out emission reduction or removal enhancement projects in other developed countries.

Kyoto Protocol – It operationalizes the United Nations Framework Convention on Climate Change by committing industrialized countries and economies in transition to limit and reduce greenhouse gases (GHG) emissions in accordance with agreed individual targets. The Convention itself only asks those countries to adopt policies and measures on mitigation and to report periodically. The Kyoto Protocol is based on the principles and provisions of the Convention and follows its annex-based structure. It only binds developed countries, and places a heavier burden on them under the principle of ‘common but differentiated responsibility and respective capabilities’, because it recognizes that they are largely responsible for the current high levels of GHG emissions in the atmosphere. In Doha, Qatar, on 8 December 2012, the Doha Amendment to the Kyoto Protocol was adopted for a second commitment period, starting in 2013 and lasting until 2020.