Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘U’
Glossary of technical terms for the use of metallurgical engineers
Terms starting with alphabet ‘U’
U-bend die – It is a die, normally used in press-brake forming, which is machined horizontally with a square or rectangular cross-sectional opening that provides two edges over which metal is drawn into a channel shape.
U-bend stress corrosion test – It evaluates a metal’s susceptibility to stress corrosion cracking (SCC) by bending a metal strip into a U-shape and exposing it to a corrosive environment. The applied strain or stress, along with the corrosive environment, can lead to the formation of cracks, indicating stress corrosion cracking susceptibility.
Ubiquitous computing – It is a scenario where computer science is made to appear everywhere.
Ugine-Sejournet process – It is a direct extrusion process for metals which uses molten glass to insulate the hot billet and to act as a lubricant.
ULCOLYSIS process – It is an electrolysis process which operates at steelmaking temperature with a molten salt electrolyte made of a slag (pyro-electrolysis).
ULCORED process – It is a direct reduction process, which produces direct reduced iron in a shaft furnace, either from natural gas or from reducing gas obtained by gasification of coal. Off-gas from the shaft is recycled into the process after carbon di-oxide has been captured, which leaves the direct reduction plant in a concentrated stream and goes to storage. The direct reduction iron step produces a solid product which is then melted using an electric arc furnace. The objective of the ULCORED process was to reduce the natural gas consumption needed to produce direct reduced iron. It is achieved by replacing traditional reforming technology with partial oxidation of natural gas. Combined with direct reduced iron carbon di-oxide capture and storage device, ULCORED can reduce 70 % carbon di-oxide emission compared with the average in the blast furnace route. The concept of the ULCORED process involves separating carbon di-oxide out of the process gas. It is characterized by an effort to adopt gas based direct reduction process to a minimized emission of green- house gases, using carbon di-oxide capture and storage technology and at the same time to a minimized use of energy. The process is designed in a way which allows for the extraction and storage of carbon di-oxide. The process is hence also dependent on carbon di-oxide capture and storage with a similar in-process capture. The process is based on the utilization of a shifter to convert the carbon mono-oxide gas from the shaft to hydrogen together with a carbon di-oxide removal unit. This opens up a new innovative evolution of the process concept. The main features of the ULCORED direct reduction process include (i) use of oxygen instead of air resulting into an off gas of nearly 100 % carbon di-oxide which is needed only to be compressed, (ii) there are possibilities to reduce the requirement of natural gas by 15 % to 20 %, and (iii) coal, biomass, bio waste gasification and hydrogen can be used as an alternative to carbon di-oxide capture and storage natural gas.
ULCOS (ultra-low carbon di-oxide steelmaking) programme – It a cooperative European research and development initiative. It seeks ways to bring about further drastic reductions in carbon di-oxide emissions from steel production. The programme’s key objective is to search for breakthrough process routes that could, in the future, when fully developed, demonstrate the potential of large cuts in carbon di-oxide emissions for the production of steel from iron ore. The programme aims to reduce carbon di-oxide emissions compared to today’s production technologies by a minimum of 50 %. Achieving such an ambitious target needs the kind of paradigm shift in the steel production which ls going to change the way steel plants presently operate around the world. ULCOS is part of a worldwide steel-industry programme designed to identify steelmaking technologies with the potential of substantial reduction of the carbon di-oxide. Under this programme attempts are being made to find an answer of making steel in the most sustainable way. ULCOS programme has four steps namely (i) process concept-building, (ii) large-scale demonstration, (iii) large-scale experimentation of a first commercial plant. (iv) deployment of the technology.
ULCOWIN process – It is an electrolysis process which operates slightly above 100 deg C in a water alkaline solution populated by small grains of ore (electro-winning process).
U-groove weld – It is a type of groove weld. It uses a U-shaped opening between two materials to be joined, typically on thicker materials. This shape allows for better control of the weld pool, resulting in a strong, robust weld. It is frequently used for thick plates where a V-groove needs excessive filling.
UL listed – It is product certification which indicates the product meets safety standards determined by ‘underwriters-laboratories’.
Ultimate analysis – It is the chemical analysis of solid, liquid, or gaseous fuels. In the case of coal or coke, it is the determination of carbon, hydrogen, sulphur, nitrogen, oxygen, and ash.
Ultimate elongation – It is the elongation at rupture.
Ultimate limit state (ULS) – This methodology forms the foundation of structural calculations and analyses, helping engineers design structures which can withstand both extreme events and everyday usage. Ultimate limit state safeguards against structural failure. It pertains to the maximum load-carrying capacity of a structure before it reaches a point of collapse or failure. Ultimate limit state design focuses on ensuring that structures can endure extreme conditions without experiencing catastrophic failure. This involves complex mathematical models which account for (i) material strength, i.e., assessing the maximum stress materials can withstand before failing, (ii) extreme load types, i.e., including rare but severe events like earthquakes, hurricanes, floods, and accidental overloads, (iii) safety factors, i.e., applying margins of safety to account for uncertainties in material properties and load estimations, and (iv) environmental conditions, i.e., considering factors like temperature extremes which can affect material performance. By designing for the ultimate limit state, engineers make sure that even under the most demanding conditions, the structure remains intact, hence protecting lives and property.
Ultimate pressure – It is the limiting pressure approached in the vacuum system after sufficient pumping time to establish that further reductions in pressure is going to be negligible.
Ultimate strength – It is the maximum stress (tensile, compressive, or shear) a material can sustain without fracture. It is determined by dividing maximum load by the original cross-sectional area of the specimen. It is also known as nominal strength or maximum strength.
Ultimate tensile strength (UTS) – It is the maximum stress which a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate tensile strength is close to the yield point, whereas in ductile materials, the ultimate tensile strength can be higher. The ultimate tensile strength is normally found by performing a tensile test and recording the engineering stress against strain. The highest point of the stress–strain curve is the ultimate tensile strength and has units of stress. The equivalent point for the case of compression, instead of tension, is called the compressive strength. Tensile strengths are rarely of any consequence in the design of ductile members, but they are important with brittle members. They are tabulated for common materials such as alloys, composite materials, ceramics, plastics, and wood. The ultimate tensile strength of a material is an intensive property. Hence its value does not depend on the size of the test sample. However, depending on the material, it can be dependent on other factors, such as the preparation of the sample, the presence or otherwise of surface defects, and the temperature of the test environment and material.
Ultra accelerator – It is a generic term for a class of vulcanization accelerators which are very active and which are normally used in very small quantities (less than 1 part).
Ultra-clean steels – These are steels with exceptionally low levels of impurities and inclusions. These steels are characterized by minimal non-metallic particles (inclusions) embedded in the steel matrix, as well as low concentrations of impurities like sulphur, nitrogen, oxygen, and phosphorus. These steels have excellent mechanical properties and / or corrosive resistance. These steels are typically considered to be difficult to machine, which result in a reduced cutting tool life.
Ultra-fine-grained (UFG) steel – It refers to a type of steel with grain sizes typically less than 1 micro-meter. These steels are characterized by their sub-micrometer or even nano-meter-scale grain structure, which can lead to substantial improvements in strength, toughness, and other mechanical properties.
Ultra-fine particles (UFPs) – These are particulate matter of nanoscale size (less than 0.1 micrometers or 100 nanometers in diameter), Regulations do not exist for this size class of ambient air pollution particles, which are far smaller than the regulated particulate matter (PM10 and PM2.5) particle classes and are believed to have several more aggressive health implications than those classes of larger particulates. Although they remain largely unregulated, the World Health Organization has published good practice statements regarding measuring ultra fine particles. There are two main divisions which categorize types of ultra fine particles. Ultra fine particles can either be carbon-based or metallic, and then can be further subdivided by their magnetic properties. Electron microscopy and special physical laboratory conditions allow people to observe ultra fine particles morphology. Airborne ultra fine particles can be measured using a condensation particle counter, in which particles are mixed with alcohol vapour and then cooled, allowing the vapour to condense around them, after which they are counted using a light scanner. Ultra fine particles are both manufactured and naturally occurring. They are the main constituent of airborne particulate matter. Owing to their large quantity and ability to penetrate deep within the lung, ultra fine particles are a major concern for respiratory exposure and health.
Ultra-hard tool materials – These are very hard, wear-resistant materials, specifically, polycrystalline diamond and polycrystalline cubic boron nitride, which are fabricated into solid or layered cutting tool blanks for machining applications.
Ultra-high-carbon steel – It is a category of carbon steel with a carbon content of 1.25 % to 2 %, making it exceptionally hard and wear-resistant. It is characterized by its high hardness and brittle nature, making it unsuitable for cold working, but ideal for applications needing extreme hardness.
Ultra-high-density poly-ethylene (UHDP) – It is a type of poly-ethylene with a considerable higher molecular weight than standard high-density poly-ethylene (HDPE). It is characterized by its exceptionally long polymer chains, resulting in unique properties like high abrasion resistance, impact strength, and chemical resistance. Ultra-high-density poly-ethylene has a molecular weight ranging from 1 million grams per mol to 7 million grams per mol, considerably exceeding high-density poly-ethylene’s range of 300,000 grams per 500,000 grams per mol.
Ultra-high frequency – It is the ITU (International Telecommunication Union) designation for radio frequencies in the range between 300 megahertz and 3 gigahertz. It is also known as the decimeter band as the wavelengths range from one meter to one tenth of a meter.
Ultra-high modulus – It refers to materials, particularly fibres like carbon fibre and polyethylene, with exceptionally high values of modulus of elasticity. This means they are very stiff and resist deformation under stress, making them suitable for applications requiring high strength and stiffness.
Ultra-high molecular-weight poly-ethylene (UHMWPE, UHMW) – It is a subset of the thermo-plastic poly-ethylene. It is also known as high-modulus poly-ethylene (HMPE). It has extremely long chains, with a molecular mass typically between 2 million and 6 million amu (atomic mass unit). The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. Ultra-high molecular-weight poly-ethylene is odourless, tasteless, and nontoxic. It embodies all the characteristics of high-density poly-ethylene (HDPE) with the added traits of being resistant to concentrated acids and alkalis, as well as numerous organic solvents. It is highly resistant to corrosive chemicals except oxidizing acids. It has extremely low moisture absorption and a very low coefficient of friction. It is self-lubricating and is highly resistant to abrasion, in some forms being 15 times more resistant to abrasion than carbon steel. Its coefficient of friction is considerably lower than that of nylon and acetal and is comparable to that of poly-tetra-fluoro-ethylene (PTFE, Teflon), but ultra-high molecular-weight poly-ethylene has better abrasion resistance than poly-tetra-fluoro-ethylene. Ultra-high molecular-weight poly-ethylene is a durable and low-friction material used in conveyor components to reduce wear and improve material flow.
Ultra-high-strength steels – Structural steels with very high strength levels are frequently referred to as ultrahigh-strength steels. The designation ultra-high-strength is arbitrary since no universally accepted strength level for the term has been established. Also, as structural steels with higher and higher strength have been developed, the strength range for which the term is applied has gradually increased. Presently, those commercial structural steels capable of a minimum yield strength of 1,380 mega pascals (MPa) are referred as ultra-high strength steels.
Ultra-high vacuum (UHV) – It is the vacuum regime characterized by pressures lower than around 0.000001 pascals. Ultra-high vacuum conditions are created by pumping the gas out of a ultra-high vacuum chamber. At these low pressures the mean free path of a gas molecule is higher than around 40 kilometers, so the gas is in free molecular flow, and gas molecules will collide with the chamber walls many times before colliding with each other. Almost all molecular interactions hence take place on several surfaces in the chamber.
Ultra-light steel – It refers to a category of steel designed and engineered to be considerably lighter than traditional steel while maintaining its strength and structural integrity. It is a key focus of research and development, particularly in industries like automotive and aerospace, where reducing weight is crucial for performance and fuel efficiency.
Ultra-low carbon bainitic (ULCB) steels – These are a class of steel with low carbon content (normally less than 0.005 % or 50 parts per million) which are processed to develop a bainitic micro-structure. These steels are known for their high strength and toughness, achieved through a combination of micro-structure refinement and controlled processing. Low carbon in these steels contribute to their good weldability and toughness.
Ultra-low carbon steel – It is a type of steel with a very low carbon content, typically below 0.005 %. This makes it highly ductile and suitable for applications needing deep drawing or where inter-granular corrosion resistance is crucial. Ultra-low carbon steels have relatively low strength compared to other steel types. These steels are also known as deep drawing steels (DDS) or interstitial-free (IF) steels.
Ultra-low cement castable – It is deflocculated castable which contains higher than 0.2 % and up to 1 % calcium oxide on a calcined basis.
Ultra-microscope – It is a microscope with a system which lights the object in a way that allows viewing of tiny particles through light scattering, and not light reflection or absorption.
Ultra-microscopic – It means too small to be seen with an ordinary microscope, i.e., below the resolution of the microscope.
Ultra-precision finishing – It is the finishing by machining processes used to alter surface characteristics such as finish, waviness, roundness, etc., with substantial removal of the work material. Examples include lapping and polishing of optical lenses, computer chips, or magnetic heads, and honing of cylinder liners.
Ultrasonic atomization – It is a process where high-frequency sound waves are used to break down a liquid into tiny droplets, creating a mist or aerosol. This is achieved by exciting capillary waves on the liquid surface, which eventually collapse and eject droplets. The process is energy-efficient and can produce a narrow droplet size distribution.
Ultrasonic beam – It is a beam of acoustical radiation with a frequency higher than the frequency range for audible sound, i.e., above around 20 kilohertz.
Ultrasonic cleaning – It means immersion cleaning aided by ultrasonic waves which cause micro-agitation. It involves the use of high-frequency sound waves (above the upper range of human hearing, or around 18 kilohertz) to remove a variety of contaminants from parts immersed in aqueous media. The contaminants can be dirt, oil, grease, buffing / polishing compounds, and mould release agents, just to name a few. Materials which can be cleaned include metals, glass, ceramics, and so on. Ultrasonic agitation can be used with a variety of cleaning agents. Typical applications found in the metals industry are removing chips and cutting oils from cutting and machining operations, removing buffing and polishing compounds prior to plating operations, and cleaning greases and sludge from rebuilt components for automotive and aircraft applications. Ultrasonic cleaning is powerful enough to remove tough contaminants, yet gentle enough not to damage the substrate. It provides very good penetration and cleaning in the smallest crevices and between tightly spaced parts in a cleaning tank.
Ultrasonic coupler (ultrasonic soldering and ultrasonic welding) – It consists of elements through which ultrasonic vibration is transmitted from the transducer to the tip.
Ultrasonic C-scan inspection – It is a method for displaying the relative attenuation of ultrasonic waves across the surface (plan view) of a structural component. An ultrasonic transducer is used to scan the surface of a material mechanically in an x-y raster scan mode while generating and receiving waves. Either the material is immersed in a water bath or columns of water are provided between the transducer and the material as a medium for ultrasonic energy transmissions. The received wave signals are electronically conditioned and measured to determine relative energy losses of the wave as it progresses through the material at each particular location on the sample. Ultrasonic C-scan has been used extensively to determine both the initial integrity of a manufactured part and the void content, and to follow the initiation and progression of damage resulting from environmental loading.
Ultrasonic fatigue testing – It involves cyclic stressing of material at frequencies typically in the range of 15 kilohertz to 25 kilohertz. The major advantage of using ultrasonic fatigue is its ability to provide fatigue-limit and near threshold data within a reasonable length of time. High-frequency testing provides rapid evaluation of the high cycle fatigue limit of engineering materials. Fatigue crack growth at extremely slow crack propagation rates is also possible with ultrasonic frequency testing. Ultrasonic fatigue testing is applicable to majority of the engineering materials, including metals, ceramics, glasses, plastics, and composites. Test data can be used for screening of high-cycle fatigue properties or extending the fatigue data already available from conventional frequency fatigue testing.
Ultrasonic frequency – It is a frequency, associated with elastic waves, which is higher than the highest audible frequency, normally regarded as being higher than 20 kilohertz.
Ultrasonic impact grinding – It is the material removal by means of an abrasive slurry and the ultrasonic vibration of a non-rotating tool. The abrasive slurry flows through a gap between the work-piece and the vibrating tool. Material removal occurs when the abrasive particles, suspended in the slurry, are struck on the downstroke of the vibrating tool. The velocity imparted to the abrasive particles causes micro-chipping and erosion as the particles impinge on the work-piece.
Ultrasonic inspection – It is a non-destructive method in which beams of high-frequency sound waves are introduced into materials for the detection of surface and sub-surface flaws in the material. The sound waves travel through the material with some attendant loss of energy (attenuation) and are reflected at interfaces. The reflected beam is displayed and then analyzed to define the presence and location of flaws or discontinuities. Majority of the ultrasonic inspection is done at frequencies between 0.1 mega-hertz and 25 mega-hertz well above the range of human hearing, which is around 20 Hetz to 20 kilo-hertz.
Ultrasonic leak detector – It is an instrument which detects ultrasonic energy produced by molecular turbulence that occurs in the transition from the laminar to turbulent flow of a gas through an orifice and that converts this energy to the audible range.
Ultrasonic machining – It is a process for machining of hard, brittle, non-metallic materials which involves the ultrasonic vibration of a rotating diamond core drill or milling tool. Rotary ultrasonic machining is similar to the conventional drilling of glass and ceramic with diamond core drills, except that the rotating core drill is vibrated at an ultrasonic frequency of 20 kilohertz. Rotary ultrasonic machining does not involve the flow of an abrasive slurry through a gap between the work-piece and the tool. Instead, the diamond tool contacts and cuts the work-piece, and a liquid coolant, normally water, is forced through the bore of the tube to cool and flush away the removed material.
Ultrasonic motor – It is a motor which relies on a component oscillating at an ultrasonic frequency.
Ultrasonics – It is the term for the field of study pertaining to pressure oscillations in air or other media which are above the range of human hearing.
Ultrasonic soldering – It is a soldering process variation in which high-frequency vibratory energy is transmitted through molten solder to remove undesirable surface films and hence promote wetting of the base metal. This operation is normally accomplished without a flux.
Ultrasonic techniques for billet inspection – This technique is poor in terms of defect resolution because of the obscuration by scattered waves from other defects. It is necessary to consider the use of surface waves to identify surface defects and with conventional methods the provision of a suitable couplant at the normal billet speeds and temperatures is normally problematical. Also, the generation of surface waves requires good control over the entry angle and with the types of surface condition commonly experienced with continuous cast material this is usually in doubt. An alternative approach to overcome these coupling problems is to resort to the use of electromagnetic methods but this still is subject to the limitations of defect detection.
Ultrasonic testing – It is also known as ultrasonic non-destructive testing. It is a method of non-destructive testing (NDT) which uses high-frequency sound waves to examine materials and components without causing damage. It is a volumetric inspection method, meaning it can locate and access defects within the material, not just on the surface. This testing method involves ultrasonic sound waves being aimed, through a coupling medium, at the material to be tested. A proportion is bounced back at the interface but the remainder enters the material and bounce from the internal surface, to the external surface, where a transducer converts them into electrical energy. This is then monitored on a cathode ray tube where results are compared with those from a calibration standard. Any deviations from the standard are visible, hence indicating cracks or internal defects.
Ultrasonic thickness gauge – It is a non-destructive testing (NDT) tool which measures the thickness of materials by using high-frequency sound waves. These gauges send ultrasonic pulses through the material and measure the time it takes for the waves to travel through the material and return to the gauge after reflecting off the back surface. This time is then converted into a thickness measurement.
Ultrasonic transducer – It is a device which converts energy, such as electrical energy, into ultrasonic vibrations (sound waves above 20 kilohertz and vice versa. These transducers are crucial for several applications, including non-destructive testing, and distance measurement.
Ultrasonic velocity – It is the velocity at which ultrasonic waves travel through a medium. These waves have frequencies above 20 kilohertz, making them inaudible to humans. The velocity of ultrasound, like that of any sound wave, is determined by the properties of the medium it is traveling through, such as air, water, or other materials. In air, it is around 340 meters per seconds. However, the speed can be significantly higher in other mediums like water. In water, it is around 1,300 meters per seconds to 1,00 meters per seconds. Temperature can influence the velocity of sound in a medium.
Ultrasonic welding – It is a solid-state welding process in which materials are welded by locally applying high-frequency vibratory energy to a joint held together under pressure.
Ultrasound – It is the sound having a frequency above the range of normal human hearing. A combination of the former description of ‘ultrasonic sound’.
Ultra-thin polymer windows – In X-ray applications, these windows refer to membranes used as a barrier between a vacuum and a sample or detector. These windows are to be thin enough to allow X-rays to pass through effectively while also being robust enough to withstand pressure differences and maintain vacuum tightness. AP5 ultra-thin polymer windows are the highest performing X-ray windows available for low and high energy X-ray analysis. [AP stands for Antero-Posterior. This refers to the direction in which the X-rays pass through the body, from the front (anterior) to the back (posterior)] AP5 windows are ideal for applications which need maximum transmission of low energy X-rays, high mechanical strength, light rejection, vacuum tightness, reliability, and increased solid angle. AP5 windows are used in applications where high temperature, light element detection is important and beryllium windows are ineffective. AP5 windows are similar in application to AP3 windows but are designed to work for detectors larger than 100 square millimeters where AP3 windows are too small. Ultra-thin polymer windows are crucial for several X-ray techniques, including soft X-ray spectroscopy, X-ray microscopy, and the development of X-ray tubes.
Ultrathin window detectors – These detectors use a thin polymer window in place of the beryllium window. The polymer window is far more transparent to low-energy X-rays. The ultrathin window is sufficient for isolating the delicate vacuum inside the detector from the environment inside the microscope column, but it is far more fragile than the standard beryllium window and is to be treated carefully. Ultrathin window detectors offer enormous potential for qualitative analysis, although quantification can be difficult because of the complicated X-ray / sample effects.
Ultraviolet – It is pertaining to the region of the electro-magnetic spectrum from around 10 nanometers to 380 nanometers. The term ultraviolet without further qualification normally refers to the region from 200 nanometers to 380 nanometers.
Ultraviolet (UV) absorption spectroscopy – It is an analytical technique which measures the wavelength-dependent attenuation of ultraviolet, visible, and near-infrared light by an atomic or molecular species. It is used in the detection, identification, and quantification of several atomic and molecular species.
Ultraviolet light – It is a form of energy occupying a position in the spectrum of sunlight beyond the violet, and having wavelengths of less than 0.4 micrometers which is the limit of visible light. Ultraviolet rays are very active chemically, show bactericidal action, and cause several substances to fluoresce. Their action accelerates deterioration of rubber pats exposed to them and can initiate polymerization.
Ultraviolet radiation – It is also known as simply UV. It is electromagnetic radiation of wave-lengths of 10 nanometers to 380 nanometers, shorter than that of visible light, but longer than X-rays. It is part of the electromagnetic spectrum, and while invisible to the human eye, it can have both positive and negative effects, including promoting vitamin D production and potentially causing skin damage. UV radiation is present in sunlight and constitutes around 10 % of the total electromagnetic radiation output from the Sun.
Ultraviolet (UV) stabilizer – It is a chemical compound which, when admixed with a thermoplastic resin, selectively absorbs ultra-violate rays.
Umbrella group – It is a loose coalition of organizations formed for addressing some common issues affecting the organizational performance.
Umpire sample – It is a sample taken, prepared, and stored in a way agreed upon by both parties to settle a dispute. It is essentially a neutral, agreed-upon sample used to resolve disagreements about the quality or characteristics of a product or material.
Unaccounted for loss – It is that portion of a boiler heat balance which represents the difference between 100 % and the sum of the heat absorbed by the unit and all the classified losses expressed as percent.
Unalloyed steel – It is also known as carbon steel. It is steel which mainly consists of iron and carbon, with minimal quantities of other elements considered residual. It is characterized by having no intentionally added alloying elements. The term ‘unalloyed’ distinguishes it from alloy steels, which contain additional elements besides iron and carbon to modify properties.
Unary diagram – It is a phase diagram of a single component system. It is a pressure-temperature diagram in which three states (phases) are represented by the three fields (solid, liquid, and gas). As per the phase rule, three phases can exist in stable equilibrium only at a single point on a unary diagram. Stable equilibrium between any two phases occur along their mutual boundary and invariant equilibrium among all the three phases occurs at the triple point, where the three boundaries intersect.
Unbiased estimator – It is a sample statistic for which the mean of its sampling distribution is equal to the population parameter it is designed to estimate. An estimator whose expected value (namely the mean of the sampling distribution) equals the parameter it is supposed to estimate. This is considered a desirable property of an estimator. In general, unbiased estimators are preferred to biased estimators of population parameters. There are rare cases, however, when biased estimators are preferred since they are much more efficient than alternative estimators.
Unbond – It is an area within a bonded interface between two adherends in which the intended bonding action failed to take place, or where two layers of prepreg in a cured component do not adhere to each other. It is also used to denote specific areas deliberately prevented from bonding in order to simulate a defective bond, such as in the generation of quality standards samples.
Unburned brick – It is the brick manufactured by processes which do not involve firing of the finished product.
Unburned combustibles – It is the combustible portion of the fuel which is not completely oxidized.
Uncensored cases – In survival analysis, those subjects who experience the event of interest during the observation period of the study.
Uncertainty – It is the notion that any measurement which involves estimation of any quantity cannot be exactly reproducible. It is an expression of the degree to which a value (e.g., the future state of the climate system) is unknown. Uncertainty can result from lack of information or from disagreement about what is known or even knowable. It can have several types of sources, from quantifiable errors in the data to ambiguously defined concepts or terminology or uncertain projections of human behaviour. Uncertainty can hence be represented by quantitative measures (e.g., a range of values calculated by different models) or by qualitative statements (e.g., reflecting the judgment of a team of experts).
Uncertainty of measurement – It is a parameter, associated with the result of a measurement, which characterizes the dispersion of the values which can reasonably be attributed to the measurand. The parameter can be, for example, a standard deviation (or a given multiple of it), or the half width of an interval having a stated level of confidence. Uncertainty of measurement comprises, in general, many components. Some of these components can be evaluated from the statistical distribution of the results of series of measurements and can be characterized by experimental standard deviations. The other components, which can also be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information. It is understood that the result of the measurement is the best estimate of the value of the measurand, and that all components of uncertainty (including those arising from systematic effects) such as components associated with corrections and reference standards, contribute to the dispersion.
Uncertainty principle – It is, also known as Heisenberg’s indeterminacy principle. It is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position and momentum, can be simultaneously known. In other words, the more accurately one property is measured, the less accurately the other property can be known. More formally, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the product of the accuracy of certain related pairs of measurements on a quantum system, such as position ‘x’, and momentum ‘p’. Such paired-variables are known as complementary variables or canonically conjugate variables.
Uncoiler – It is an equipment, frequently referred to as a decoiler. It is used to unwind and feed coils of material such as metal into a processing line. It is a material handling equipment located at the beginning of a process line used to hold and safely pay off or uncoil the strip. It controls the speed and direction of the strip of metal as it unwinds from the coil and is sent to the line for processing, such as slitting or tube mill entry. It is normally used in several industries where continuous material flow is needed.
Unconventional metallurgy – It refers to metal systems. Some of these systems cannot be formed by melting and casting. These are fully homogeneous, fully dense, fine grained, segregation free, high strength materials. In majority of the cases, these systems do not compete with existing materials.
Unctuous – It is a general term expressing the slippery feel of a lubricant when rubbed with the fingers. However, it is recommended that this term not be used in English
Uncut value – It is the actual assay value of a core sample as opposed to a cut value which has been reduced by some arbitrary formula.
Undeformed material – It is a material which has not undergone any change in its original shape or size because of the application of force or external factors. It is in its original state, before any deformation has occurred.
Under-ageing – It is an artificial ageing treatment which fails to achieve maximum or optimum increase in mechanical properties / hardening. It is caused either by processing for an insufficient time or at too low a temperature.
Under-bead crack – It is a crack in the heat-affected zone of a weld normally not extending to the surface of the base metal.
Under-belt clearance – It is the vertical space between the conveyor belt and the components beneath it, such as pulleys or supports. Regular measurements and adjustments are essential to ensure adequate under-belt clearance, preventing issues like material jams.
Undercoat – It is a deposited coat of material which acts as a substrate for a subsequent thermal spray deposit.
Undercooling – It is also known as supercooling or freezing point depression. It is the process where a liquid or gas is cooled below its freezing point without solidifying or crystallizing. This state of being below the freezing point without solidification is a normal phenomenon in several natural and engineered systems.
Undercure – It is a condition of the moulded article resulting from the allowance of too little time and / or temperature or pressure for adequate hardening of the moulding.
Undercut – Undercut is a reduction in the base metal thickness at the weld toe. This is caused by an oversized liquid weld pool which can result from excessive amperage or oversized electrode. During the final or cover pass the exposed upper edges of the bevelled weld preparation tend to melt and to run down into the deposited metal in the weld groove. The result is a groove which can be either intermittent or continuous, with more or less sharp edges along the weld reinforcement.
Undercut shape – It is a shape in which material has been removed to create an overhang.
Underdraft – It is a condition wherein a metal curves downward on leaving a set of rolls because of higher speed in the upper roll.
Underfill – In weldments, it is a depression on the face of the weld or root surface extending below the surface of the adjacent base metal. It is also a portion of a forging which that has insufficient metal to give it the true shape of the impression.
Underfilm corrosion – It is the corrosion which occurs under organic films in the form of randomly distributed threadlike filaments or spots. In several cases this is identical to filiform corrosion.
Underfiring – It consists of firing a porcelain enamel coating at a lower temperature than that desired, allowing an insufficient length of time in the furnace, or applying too heavy a layer of the enamel. Likely to cause blisters or boiling of the ground coat through the cover coat, or the enamel ground coat can fish-scale before the cover coat can be applied and fired.
Underground conveyor – It is a conveyor system positioned below the earth’s surface, normally utilized in mining or tunneling contexts. Ensuring regular maintenance is essential to uphold the dependability and safety of underground conveyors functioning in demanding environments.
Underground storage tank (UST) – It is a tank which is located at least partially underground and which is designed to hold gasoline or other petroleum products or chemicals.
Under-reporting – It normally refers to some issue, incident, and statistic etc., which individuals, responsible agencies, or organizations have not reported, or have reported as less than the actual level or amount. Under-reporting of accidents and incidences, for example, makes it hard to figure the actual number of accidents and incidences in the organization. of crimes. Under reporting is an emphasis on injury rates as a measure, particularly when related to reward systems, can lead to such events not being reported so as to ‘maintain’ performance. Under-reporting is a failure in data reporting.
Under-sampling – It means sampling a signal at less than the Nyquist rate. It can produce alias frequencies or other artifacts.
Underside bed cover – It is the metal sheeting used to shield the lower side of a conveyor.
Underside take-up – It is a take-up segment situated beneath the bed of a belt conveyor.
Under size – It consists of particles in a screen overflow which are smaller than the normal dimensions of the screen apertures. It is also the smaller of two classified products. In the case of ore pulp or fine coal, the undersize is the overflow and the oversize is the underflow. Under size is a drill hole which is not to size because of gauge loss on the bit and / or the reaming shell with which it has been drilled. It is also a bit or reaming shell, the diametric dimensions of which are less than specified as standard. Under size is also that part of a crushed material which passes through a screen. It is also the material in a product of size smaller than the reference size which can be expressed as a percentage of the product.
Undersize powder – It consists of powder particles smaller than the minimum permitted by a particle size specification.
Understeer – It is a vehicle dynamics terms used to describe the sensitivity of the vehicle to changes in steering angle associated with changes in lateral acceleration. This sensitivity is defined for a level road for a given steady state operating condition by the International Organization for Standardization (ISO) in document 8855. Whether the vehicle is understeer depends on the rate of change of the understeer angle.
Understeer angle – It is the quantity of additional steering (at the road wheels, not the hand wheel) which is to be added in any given steady-state maneuver beyond the Ackermann steer angle which is the steer angle at which the vehicle travels around a curve when there is no lateral acceleration needed (at negligibly low speed).
Understeer gradient (U) – It is the rate of change of the understeer angle with respect to lateral acceleration on a level road for a given steady state operating condition.
Understressing – It means applying a cyclic stress lower than the endurance limit. This can improve fatigue life if the member is later cyclically stressed at levels above the endurance limit.
Under-tensioning – It is the condition in which a conveyor belt is insufficiently tensioned, leading to sagging or inadequate support. Regular assessments are needed to prevent under-tensioning and ensure optimal belt tension for efficient material handling.
Underwater cutting and welding – These are metal-working techniques used by underwater divers in underwater construction, marine salvage and clearance diving applications. Majority of the underwater welding is direct current wet stick welding, and majority of the underwater metal cutting is immersed oxygen-arc and shielded metal-arc cutting, though other technologies are available and sometimes used. These processes are mostly applied to steel structures as that is the most common arc-weldable material used in the underwater environment.
Underwriters Laboratories (UL) – It is a safety organization which provides third-party certification, ensuring products meet safety standards and are safe for use. Underwriters Laboratories is particularly well-known for its role in electrical safety, having established standards and testing for electrical devices and components. It develops and publishes industry standards for electrical products, ensuring they meet safety requirements.
Undulating surface – It is the surface which is not flat, but rather has a wavy or rippled shape, like the surface of a wave in the ocean or the hills of a landscape. It describes a surface which goes up and down in a smooth, flowing pattern.
Uneconomic occurrence – It is the materials of estimated quantity, which are too low in grade or for other reasons are not considered potentially economic. Hence, uneconomic occurrence is not a part of a Mineral resource. If quantity and quality are considered worthy of reporting, it is to be recognized that an Uneconomic occurrence cannot be exploited without major technological and / or economic changes, which are not currently predictable.
Unequal angle – It is structural steel profile resembling an ‘L’ shape where the two legs (sides) are of different lengths. This differs from an equal angle, where both legs are of the same length. The unequal legs provide flexibility in applications where varying support or structural needs are needed.
Unequal section – In metal casting, It is a section which has certain areas very large as compared to other areas.
Unfired pressure vessel – It is a vessel designed to withstand internal pressure, neither subjected to heat from products of combustion nor an integral part of a fired pressure vessel system.
Uniaxial compaction – It is a powder compaction method that uses pressure applied in a single direction, typically through a punch, to compress powder into a solid form. This process is normally used to form tablets, metal compacts, and other solid objects from powders. The applied pressure is directed along a single axis, normally through a punch which moves into a die cavity filled with powder.
Uniaxial compression – It refers to applying a load or stress to a material in only one direction, normally along the length of a cylindrical sample, while the other dimensions are free to expand or contract. This type of compression is frequently used to measure the strength of materials, especially rocks and soils.
Uniaxial compression testing – It is a method used to determine the compressive strength of a material by applying a compressive load along a single axis. This test is frequently used to evaluate the short-term strength and elastic properties of rocks, concrete, and other materials. It involves subjecting a sample to a controlled and increasing compressive stress until it fails, and then measuring the stress at failure.
Uniaxial hot pressing – It is a process in which pressure is applied in a single direction to a powdered material while simultaneously heating it to a high temperature. This combined heat and pressure compacts and densifies the powder, typically to create a solid, dense product. The process is used for several materials, including ceramics, metals, and composites.
Uniaxial load – It is a condition whereby a material is stressed in only one direction along the axis or centre-line of component parts.
Uniaxial strain – It is an increase (or decrease) in length resulting from a stress acting parallel to the longitudinal axis of the sample.
Uniaxial stress – It is a state of stress in which two of the three principal stresses are zero.
Uniaxial tension – It refers to the application of a pulling force (tension) on a material along a single direction or axis. This type of loading is a fundamental test used to characterize the mechanical properties of materials, particularly isotropic materials.
Uniaxial tension testing – It is a mechanical test where a material sample is subjected to a single, uniform pulling force (tension) along one axis until it fractures. This test is a fundamental way to determine a material’s mechanical properties like yield strength, Young’s modulus, and ultimate tensile strength.
Unibody – It is a type of body / frame construction in which the body of the vehicle, its floor pan and chassis form a single structure. Such a design is normally lighter and more rigid than a vehicle having a separate body and frame.
Unicode – It is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world’s writing systems that can be digitized. Version 16.0 of the standard defines 154,998 characters and 168 scripts used in different ordinary, literary, academic, and technical contexts. Several common characters, including numerals, punctuation, and other symbols, are unified within the standard and are not treated as specific to any given writing system.
Unidirectional compacting – It means compacting of powder in one direction.
Unidirectional composite – It is a type of composite material where all reinforcing fibres are aligned in a single, parallel direction. This alignment provides the material with its highest strength and stiffness in that direction. Essentially, it is a composite with fibres running in one direction only.
Unidirectional flux – It is also called unidirectional flow. It refers to the movement of something (like data, energy, or fluid) in a single direction, without any ability to flow back or change direction. In different contexts, it describes systems where information or materials are processed or transported in a non-reversible way.
Unidirectional laminate – It is a reinforced plastic laminate in which substantially all of the fibres are oriented in the same direction.
Unified life-cycle engineering (ULCE) – It is also known as concurrent engineering. It is a design approach which considers the entire product life cycle, from initial design to disposal, to optimize quality and reduce costs. It integrates different engineering disciplines and utilizes computer-aided tools to assess and improve product quality throughout its lifecycle. Unified life-cycle engineering goes beyond traditional design, considering not just the design phase but also manufacturing, operation, maintenance, and eventual disposal of a product.
Unified numbering system for metals and alloys – It provides methods of correlating several internationally used metal and alloy numbering systems currently published by engineering bodies, societies, trade associations, and producers of metals and alloys. This numbering system is normally referred to through majority of engineering industries. The system helps avoid the confusion caused by the use of more than one identification number for the same type of metal or alloy. Such uniformity provides an efficient method for referencing and cross-referencing material types. The unified numbering system identifies nine series of designations for ferrous metals and their alloys. Each unified numbering system designation consists of a single-letter prefix followed by five digits. In majority of the cases the letter is suggestive of the family of metals identified, e.g., ‘A’ for aluminum, ‘F’ for cast irons, ‘T’ for tool steel, and ‘S’ for stainless steels.
Uniform approach – It means conforming to one principle, standard or rule. It seeks to develop and assess broad adaptation strategies on the basis of a comprehensive perception of vulnerability which can exist. (e.g., across sectors, across regions and across development challenges).
Uniform building code – It is a standardized set of regulations which govern the design, construction, alteration, and repair of buildings. These codes are intended to protect public health, safety, and general welfare by ensuring buildings are built in accordance with established standards. Uniform building code aims to provide consistent standards for safe construction across different jurisdictions, minimizing variations and ensuring that buildings meet the same safety expectations.
Uniform corrosion – It is a type of corrosion attack (deterioration) uniformly distributed over a metal surface. It is the corrosion which proceeds at approximately the same rate over a metal surface. It is also called general corrosion.
Uniform deformation – It refers to a change in shape or size of an object where the change is consistent and evenly distributed throughout the object. This means that the deformation occurs uniformly across the object, rather than being localized or concentrated in specific areas.
Uniformly distributed impact tests – These tests are used to evaluate the ability of materials to withstand impacts where the force is spread evenly over a surface. Examples include testing the impact resistance of materials like plastics or composites. These tests help engineers understand how materials behave under impact and can be used to design safer and more durable products.
Uniform distribution – Uniform distributions are appropriate for cases when the probability of achieving an outcome within a range of outcomes is constant. An example is the probability of observing a crash at a specific location between two consecutive post miles on a homogenous section of freeway.
Uniform elongation – It is the elongation at maximum load and immediately preceding the onset of necking in a tensile test.
Uniform fine grain (UFG) microstructure – It refers to a material with a high density of small, evenly distributed grains, typically less than 1 micrometer in size. This microstructure is characterized by a high fraction of high-angle grain boundaries (HAGBs), which contribute to improved mechanical properties like strength and toughness.
Uniformity – It is a measure of the homogeneity of a substance’s composition or character.
Uniform report format – It is a standard format which is used for uniform reporting.
Uniform reporting – It refers to the standardized method of collecting, organizing, and presenting data within an organization to ensure consistency, accuracy, and compliance across all reporting processes.
Uniform sections – In metal castings, these are the sections which re having uniform wall thickness.
Uniform strain – It is the strain occurring prior to the beginning of localization of strain (necking). It is the strain to maximum load in the tension test.
Unijunction transistor – It is a three terminal semi-conductor device with a definite switching characteristic and only one P-N junction.
Uninterruptible power supply (UPS) – It is also called uninterruptible power source. It is a type of continual power system which provides automated backup electric power to a load when the input power source or mains power fails. An uninterruptible power supply differs from a traditional auxiliary / emergency power system or standby generator in that it provides near-instantaneous protection from input power interruptions by switching to energy stored in battery packs, super-capacitors or flywheels. The on-battery run-times of most uninterruptible power supplies are relatively short (only a few minutes) but sufficient to ’buy time’ for initiating a standby power source or properly shutting down the protected equipment. Almost all uninterruptible power supplies also contain integrated surge protection to shield the output appliances from voltage spikes. A uninterruptible power supply is typically used to protect hardware such as computers, data centers, tele-communications equipment or other electrical equipment where an unexpected power disruption can cause injuries, fatalities, serious business disruption or data loss. Uninterruptible power supply units range in size from ones designed to protect a single computer (around 200 volt-ampere rating) to large units powering entire data centres or buildings.
Union – It is a pipe fitting which is similar to a coupling except that it is designed to allow quick and convenient disconnection of pipes for maintenance or fixture replacement.
Unipolar motor – It is a heteropolar motor. In this design all currents flow in only one direction.
Unique process – It is a distinctive, original method or approach which is used to achieve a specific result, offering a competitive advantage or a memorable experience. It is frequently characterized by a distinct set of steps, tools, or techniques that differentiate it from other processes.
Unique product – It is the product which is the only one of its kind, possessing qualities or attributes that distinguish it from other products in the market. This uniqueness can stem from several factors, including innovation, superior quality, exceptional customer experience, or a strong brand identity.
Unit based pricing – It is a method where the cost of a product or service is stated per unit of measure, such as per kilogram, per litre, or per item. This helps the customers to compare the cost of different packages or quantities to make more informed buying decisions.
Unit cell – It is a parallelepiped element of crystal structure, containing a certain number of atoms, the repetition of which through space builds up the complete crystal.
Unit cost – It is the total expense incurred by the organization to produce, store and sell one unit of a product. Unit cost can be represented by the equation ‘unit cost = variable cost per unit of product + total fixed cost / output’. Unit costs include fixed costs, overhead costs, material costs and manpower costs.
United Nations Framework Classification (UNFC) – UNFC has been designed to meet, to the extent possible, the needs of applications pertaining to (i) policy formulation based on resource studies, (ii) resources management functions, (iii) corporate business processes, and (iv) financial capital allocation. UNFC is a principles-based system in which the products of a resource project are classified on the basis of the three fundamental criteria of environmental-socio-economic viability (E), technical feasibility (F), and degree of confidence in the estimate (G), using a numerical coding system. Combinations of these criteria create a three-dimensional system. Categories (e.g., E1, E2, E3) and, in some cases, sub-categories (e.g., E1.1) are defined for each of the three criteria. The first set of Categories (the E axis) designates the degree of favourability of environmental-socio-economic conditions in establishing the viability of the project, including consideration of market prices and relevant legal, regulatory, social, environmental and contractual conditions. The second set (the F axis) designates the maturity of technology, studies and commitments necessary to implement the project. These projects range from early conceptual studies through to a fully developed project that is producing, and reflect standard value chain management principles. The third set of categories (the G axis) designates the degree of confidence in the estimate of the quantities of products from the project. The Categories and Sub-categories are the building blocks of the system, and are combined in the form of “Classes”. UNFC can be visualized in three dimensions, or represented in a practical two-dimensional abbreviated version.
United Nations Framework Classification (UNFC) for resources – It is a resource project-based and principles-based classification system for defining the environmental-socio-economic viability and technical feasibility of projects to develop resources. UNFC provides a consistent framework to describe the level of confidence of the future quantities produced by the project. Sources, such as solar, wind, geothermal, hydro-marine, bioenergy, injection for storage, hydrocarbons, minerals, nuclear fuels and water, are the feedstock to resource projects from which products can be developed. The sources may be in their natural or secondary (anthropogenic sources, tailings, etc.) state. Products of the project may be bought, sold or used, including electricity, heat, hydrocarbons, hydrogen, minerals, and water. It is noted that with some projects, such as for renewable energy, the products (electricity, heat, hydrogen etc.) are different from the sources (wind, solar irradiation etc.). In other projects the products and sources may be similar e.g., in petroleum projects both the sources and products are oil and / or gas, although the fluid state and properties may change from reservoir to surface conditions.
United Nations Framework Convention on Climate Change (UNFCCC) – The Convention took effect in March 1994. It has universal membership. The 198 countries that have ratified the Convention are called Parties to the Convention. Preventing ‘dangerous’ human interference with the climate system is the ultimate aim of the UNFCCC. The ultimate objective of the Convention is to stabilize greenhouse gas concentrations ‘at a level that would prevent dangerous anthropogenic (human induced) interference with the climate system’. It states that ‘such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened, and to enable economic development to proceed in a sustainable manner’. The aim of UNFCCC is achieved by encouraging countries to work together on adaptation and mitigation measures, including reducing greenhouse gas emissions.
United Nations Industrial Development Organization (UNIDO) – It is a specialized agency of the United Nations dedicated to promoting industrial development, particularly in developing countries, to achieve inclusive and sustainable growth. UNIDO aims to encourage and accelerate industrialization, inclusive globalization, and environmental sustainability. UNIDO provides technical cooperation, research, policy advice, and knowledge transfer to member countries.
Unit factor – It is a conversion factor which expresses the relationship between different units of measurement, allowing for unit conversions. It essentially acts as a ratio where the numerator and denominator represent the same value but in different units, making the entire fraction equal to one. Unit factor consists of statements used in converting between units.
Unit plot plan – Unit plot plan shows the coordinates of steel column centre-lines and extremities of buildings. The equipment arrangement drawing is an updated unit plot plan where equipment outlines are added to the unit plan drawing. It shows the positions of equipment with outlines drawn to scale. Several viable drawings are normally made in order to optimize and meet process needs.
Unit load depth – In forklift operation, it refers to the distance from the face of the forks to the centre of gravity of the load being lifted. This measurement is crucial for determining the forklift’s load capacity, since the rated capacity is based on a specific load centre, typically 500 millimeters.
Unit of length (meter) – The meter is the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second.
Unit of mass (kilogram) – The kilogram is the unit of mass which is equal to the mass of the international prototype of the kilogram.
Unit of time (second) – The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.
Unit of electric current (ampere) – The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 0.0000002 newtons per meter of length.
Unit of thermodynamic temperature (kelvin) – The kelvin (K), unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The unit kelvin and its symbol K is also used to express an interval or a difference in temperature. In addition to the thermodynamic temperature (symbol T), expressed in kelvin, use is also made of Celsius temperature (symbol t) defined by the equation t = T – To where To = 273.15 K by definition. To express Celsius temperature, the unit ‘degree Celsius’ which is equal to the unit ‘kelvin’ is used; in this case ‘degree Celsius’ is a special name used in place of ‘kelvin’. An interval or difference of Celsius temperature can be, however, expressed in kelvins as well as degrees Celsius.
Unit of amount of substance (mole) – The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities are to be specified and can be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. In the definition of the mole, it is understood that unbound atoms of carbon-12, at rest, and in their ground state, are referred to.
Unit of luminous intensity (candela) – The candela is the luminous intensity, in a given direction, of a source which emits monochromatic radiation of frequency 540 x (10 to the power 12) hertz and which has a radiant intensity in that direction of (1/683) watt per steradian.
Unit power – It is the net quantity of power needed during machining or grinding to remove a unit volume of material in unit time.
Unit vector – It is a vector which has a magnitude (length) of exactly 1. It is used to specify a particular direction without regard to magnitude. It is frequently used to represent directions, such as normal directions. Unit vectors are frequently chosen to form the basis of a vector space, and every vector in the space can be written as a linear combination form of unit vectors.
Univariant equilibrium – It refers to a state where only one independent intensive variable (like temperature or pressure) can be varied while maintaining the equilibrium of the system. This means that if one variable changes, the other is also to change to preserve the equilibrium condition.
Universal beam (UB) – It is also known as parallel flange beam. It can be I-beam or H-beam. It is a structural steel member. It features a profile which has a central web connecting the two parallel end units (flanges). For each specific beam, the surface of the top (or outside) of each flange is parallel with the surface of the bottom (or inside) of that flange. The flange essentially has a constant thickness. The web is also of a constant thickness. The thickness of the web is not equal to the thickness of the flanges. There are a large numbers sizes and shapes of universal beams which are specified in different national and international standards. Universal beam has the most efficient cross-sectional profile since majority of its material is located away from the neutral axis providing a high second moment of area, which in turn increases the stiffness, hence resistance to bending and deflection. Universal beams are designed to withstand high loads and are normally used in construction and civil engineering for structural support. In a structural steel frame work, it forms the main horizontal member spanning between adjacent columns or as a secondary member transmitting floor loading to the main beams. The web of a universal beam resists shear forces, while its flanges resist most of the bending moment experienced by the beam.
Universal column (UC) – H-beam is also known as universal column. It is an economical section with more optimized section area distribution, and more strength-to-weight ratio. It is also been called wide flange beam. The use of these beams is very common.
Universal forging mill – It is a combination of four hydraulic presses arranged in one plane equipped with billet manipulators and automatic controls. It is used for radial or draw forging.
Universal gas constant – It is denoted as ‘R’. It is a physical constant which appears in the ideal gas law (PV=nRT). It relates the pressure, volume, temperature, and number of moles of an ideal gas. Essentially, ‘R’ is a constant of proportionality which converts the number of moles and temperature into units of pressure and volume.
Universal joint – It is also called a universal coupling or U-joint. It is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is normally used in shafts which transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90-degree to each other, connected by a cross shaft. The universal joint is not a constant-velocity joint. Universal joints are also sometimes called by numerous eponymous names such as cardan joint, Hooke joint or Hooke’s joint, Spicer joint, and Hardy Spicer joint.
Universal mills – Universal mills have roll configuration, where there are two horizontally mounted rolls and two vertically mounted rolls which are driven through transmission of bevel gear wheels. The vertical rolls act by edging effect on lateral sides of the work piece, which leads to creating its lateral ‘walls’, precision angles and sharp edges. The edging rolls are used to be mounted from the front of the mill stand, less frequently from the rear side, but sometimes also from both sides of the mill. Universal mills are used for rolling of slabs, universal plates, and universal steel sections such as beams etc. To enable rolling of wide-flange beams, the vertical rolls are mounted in the same plane with axes of rolls placed horizontally. Only the horizontal rolls are driven.
Universal mill stand –The universal rolling mill stand is a four-way rolling stand used in the rolling of section normally beams, where in the section is shaped from all four sides. It consists of two vertically mounted rolls and two horizontally mounted rolls. The vertical rolls are idle and are arranged between the bearing chocks of the horizontal rolls in the vertical plane. Vertical rolls are used to control the width of the work piece bar simultaneously during rolling.
Universal shears – These shears are usually designed for higher product speeds and normally used for head end and tail end cropping as well as for cobble cutting. In these shears the cutting is initiated by automatic pulse. Universal shears are generally of continuous running type.
Universal waste – It is a subcategory of hazardous waste which is widely generated by both households and industries, and includes items like batteries, fluorescent lamps, mercury-containing devices, and certain pesticides. It is characterized by a relatively lower risk to human health and the environment when properly handled and transported. Universal waste regulations streamline the collection and disposal of these materials, encouraging proper recycling and treatment.
Universe – Universe is synonymous with population and is found primarily in older statistical textbooks. Majority of the newer textbooks and statistical literature use population to define the experimental units of primary interest.
Unload area – It is the designated region in a conveyor system where materials are systematically removed or offloaded. Regular inspections and upkeep are imperative to ensure the efficiency of material unloading processes and to prevent bottlenecks or disruption.
Unload chute – It is a channel or passage designed for the controlled discharge of materials from the conveyor. Routine checks are necessary to prevent blockages, ensure proper alignment, and maintain the integrity of the unload chute.
Unload station – It is a designated area along the conveyor line where materials are unloaded or transferred. Periodic inspections are necessary to maintain the functionality, safety, and efficiency of the unload station.
Unlubricated sliding – It is the sliding without lubricant but not necessarily under completely dry conditions. Unlubricated sliding is frequently used to mean ‘not intentionally lubricated’, but surface species such as naturally formed surface oxides and other interfacial contaminants can act in a lubricious manner in nominally lubricated sliding.
Unmeasured heterogeneity – It is an unmeasured characteristic of one’s cases which is related to one or more explanatory variables in the study, as well as the study endpoint. Part or all of the supposed ‘effect’ of the explanatory variables on the study endpoint is actually attributable to this unmeasured confounding factor.
Unmixed zone – At fusion line, it is a thin layer of the base metal which melts during welding but does not mix with the filler metal. It solidifies with a cast-like micro-structure, retaining the original composition of the base metal rather than the chemically different weld filler.
Unnotched Charpy impact strength – In contrast to notched Charpy impact strength, it is a measure of a material’s resistance to fracture under impact loading without a pre-existing notch. It essentially determines how much energy a material can absorb before fracturing when subjected to a sudden impact.
UN number – It is a four-digit code used to note hazardous and flammable substances.
Unpaired electron – It is an electron which occupies an orbital of an atom singly, rather than as part of an electron pair. Each atomic orbital of an atom (specified by the three quantum numbers ‘n’, ‘l’, and ‘m’) has a capacity to contain two electrons (electron pair) with opposite spins. As the formation of electron pairs is frequently energetically favourable, either in the form of a chemical bond or as a lone pair, unpaired electrons are relatively uncommon in chemistry, because an entity that carries an unpaired electron is usually rather reactive. In organic chemistry they typically only occur briefly during a reaction on an entity called a radical. However, they play an important role in explaining reaction pathways.
Unsaturated compound – It is a molecule which contains at least one double or triple bond between carbon atoms, as opposed to only single bonds. These double or triple bonds are the defining feature of unsaturated compounds. Examples include alkenes (with double bonds) and alkynes (with triple bonds).
Unsaturated polyester resin (UPR) – It is a liquid polymer which becomes solid upon curing, frequently with the aid of a cross-linking agent like styrene and a hardener. It is a type of polyester resin formed by the reaction of polyacids and poly-alcohols, with the presence of unsaturated double bonds along the polymer chain. This structure allows for further polymerization and the formation of a rigid, durable material.
Unsaturated steam – It is the most common form of steam. It normally contains wetness from non-vapourized water molecules which are carried over into the distributed steam. It is also known as wet steam.
Unsaturation – It is a chemical condition occurring in carbon compounds when the full combining power of two adjacent atoms is not satisfied by other elements, resulting in double or triple bonds. These bonds are available for reaction with sulphur (vulcanization) and are susceptible to rupture (breakage) or cross linking on exposure to heat or light resulting in deterioration of properties.
Unshaped refractory – It is a mixture consisting of aggregate and bond, prepared ready for use either directly in the condition in which they are supplied or after addition of one or more suitable liquids and which satisfies the requirements of refractoriness. Such a mixture can contain metallic, organic, or inorganic fibrous material and can be either dense or insulating. An insulating mixture is one whose true porosity is not less than 45 % when determined as per International Organization for Standardization (ISO) standard ISO 5016, using a test piece fired to specified conditions.
Unshielded twisted pair – It means two wires wrapped around each other, but without a conductive cover.
Unspecified method – It is a situation in which a method’s behaviour or implementation is not clearly or explicitly described. This means the details of how the method works are left undefined or unspecified, potentially allowing for variations across different implementations or situations.
Unsprung mass – It is sometimes called unsprung weight. Unsprung mass of a vehicle is the mass of the suspension, wheels or tracks (as applicable), and other components directly connected to them. This contrasts with the sprung mass (or weight) supported by the suspension, which includes the body and other components within or attached to it. Components of the unsprung mass include the wheel axles, wheel bearings, wheel hubs, tyres, and a portion of the weight of driveshafts, springs, shock absorbers, and suspension links. Brakes that are mounted inboard (i.e., as on the drive shaft, and not part of the wheel or its hub) are part of a vehicle’s sprung mass.
Unstable crack growth – It is a general term describing a situation in which the elastic strain energy released by an increment of crack growth by any mechanism (i.e., static load, fatigue, creep, or corrosion) is sufficient to cause the crack to grow another increment in length, in other words, for the crack to become self-propagating.
Unstable equilibrium – It refers to a state where a system is in balance, but any small disturbance causes it to move away from that balance, leading to a change in position or state. In this scenario, the potential energy of the system increases as it deviates from the equilibrium point, frequently resulting in the system shifting to a new equilibrium state which is lower in energy. This concept is crucial in understanding how systems behave under different forces and conditions.
Unsteady flow – It refers to a flow where the fluid properties (like velocity, pressure, density) change with time at any given point.
Unsupported length – It refers to the distance between points where a structural member, like a column or beam, is laterally supported, meaning it is free to deflect or buckle between those points. In simpler terms, it is the ‘clear length’ of the member between supports.
Unsymmetric laminate – It is a laminate having an arbitrary stacking sequence without midplane symmetry.
UOE process – It is short for U-ing, O-ing, and expanding. It is a method which is used to manufacture large-diameter steel pipes. It involves forming a steel plate into a U-shape, then bending it into an O-shape, and finally, expanding the pipe to its final diameter. This process is normally used for producing pipes used in oil and gas transportation, offshore structures, and water supply. In UOE process, different steps are (i) crimping in which the edges of the steel plate are crimped (formed) into a circular arc to prepare them for welding, (ii) U-ing in which the crimped plate is pressed into a U-shape using a U-press., (iii) O-ing in which the U-shaped plate is further formed into a circular or O-shape using an O-press, (iv) welding in which the seam where the edges meet is welded, creating a circular pipe, and (v) expanding in which the pipe is finally expanded to achieve the desired diameter using a mechanical expander or internal pressure. The UOE process is known for its ability to produce high-quality, large-diameter pipes efficiently and economically.
Up-cut milling – It is also known as conventional milling. It is a machining process where the milling cutter’s direction of rotation is opposite to the direction of the work-piece’s movement. This means the cutter moves against the work-piece as it removes material. Chip thickness increases progressively from the start to the end of the cut.
Upender – It is a conveyor accessory or system designed to rotate materials from a horizontal to a vertical position or vice versa. Regular inspections and lubrication are essential to ensure the smooth operation and safety of upender devices.
Upper bainite – It is a microstructure in steel formed at higher temperatures (typically 550 deg C to 400 deg C) during isothermal transformation from austenite. It consists of laths (thin plates) of ferrite (iron with very little dissolved carbon) arranged in sheaves (clusters), with carbides (like cementite) typically forming between the ferrite laths, rather than within them. This contrasts with lower bainite, where carbides also precipitate within the ferrite laths.
Upper bound – It is a limit which defines the maximum value a quantity or function can reach. It is frequently used in algorithms and mathematics to describe a worst-case scenario or the maximum growth rate of an algorithm. In mathematics, an upper bound of a set is a number higher than or equal to all elements in the set.
Upper-bound analysis – It is a method of establishing a maximum limit or value which a quantity or process can reach. It is used to set a ceiling on potential values or performance, frequently in a worst-case scenario, providing a safety margin or understanding of the maximum possible outcome.
Upper bound elemental technique (UBET) – It is a numerical method used in computational simulation, particularly in metal forming processes like forging and extrusion. It provides an approximate, but frequently faster, solution for predicting loads, metal flow, and preform shapes compared to more complex methods. Upper bound elemental technique leverages the principle of upper bound theory to calculate an upper limit on the load required for a given process.
Upper bound method – It is based on calculations of the energy of deformation. Calculation of the velocity field is needed in this method. This approach has been now substituted by the finite element method (FEM). There are, however, some advantages of this method, which allow formulation of efficient optimization tasks for industrial processes.
Upper-bound theorem of plasticity – It is a method used to determine the collapse load of a structure by postulating a kinematically admissible collapse mechanism. It provides an estimate of the collapse load which is always higher than or equal to the true collapse load. This means the calculated load using the upper-bound method is an over-estimate, providing a safety margin in structural analysis.
Upper control limit (UCL) – It is a horizontal line on the control chart which defines the maximum acceptable variation from the process mean. It is one of the three key elements of a control chart, along with the centre-line (representing the process mean) and the lower control limit (LCL). The upper control limit, along with the local control limit, helps determine when a process is potentially ‘out of control’. The upper control limit serves as a threshold to indicate when a data point can be a result of special causes (non-random variation) and not just common causes (random variation within the process).
Upper critical strain – It is the minimum quantity of cold work needed prior to annealing or solution treatment to produce a fine recrystallized equiaxed grain structure by eliminating the cold worked structure of elongated grains.
Upper critical temperature – It is the temperature above which austenite is the stable phase. It is also called the A3 temperature.
Upper punch -It is the member of the compacting tool set or die which closes the die and forms the top of the part being produced.
Upper ram – It is the part of a pneumatic or hydraulic press which is moving in an upper cylinder and transmits pressure to the upper punch or set of upper punches.
Upper specification limit (USL) – It is the highest acceptable value for a quality characteristic or measurement, beyond which a product or service is considered defective or not meeting customer requirements. It is part of a specification range, along with the lower specification limit (LSL), and defines the acceptable range for a particular parameter. Upper specification limit along with the lower specification limit sets the boundaries of what is acceptable for a product or service, frequently reflecting the ‘voice of the customer’ (VOC).
U-press – It is a hydraulic press having a U-forming forming die. In this press, the plate is formed into a U-shape. The steel plate with bent edge is loaded in the vertical and horizontal direction, so that the steel plate is uniformly bent into U-shape and the mouth is close together. It is very important to control the edge opening of spring-back plate and its symmetry around the plane of symmetry.
Upsampling – It is the sampling at higher than the Nyquist rate, which makes filter design easier.
Upset – It is the localized increase in cross-sectional area of a work-piece or weldment resulting from the application of pressure during mechanical fabrication or welding. It is also that portion of a welding cycle during which the cross-sectional area is increased by the application of pressure. Upset also is bulk deformation resulting from the application of pressure in welding. The upset can be measured as a percent increase in interfacial area, a reduction in length, or a percent reduction in thickness (for lap joints).
Upset butt welding – It is a non-standard term for upset welding.
Upset cavities – These cavities can be located entirely within the heading tool, entirely within the gripper dies, or divided between the heading tool and gripper dies. The location depends largely on the severity of the upset and the preferred location of flash either for convenience in trimming or for satisfying dimensional requirements in the trimmed area. Simple forgings, needing an upset of minimum or near-minimum severity, are frequently upset with the entire cavity within the heading tool. Conversely, forgings needing an upset of higher severity are frequently forged with the entire cavity within the gripper dies.
Upset conveyor – It is a specialized conveyor which is used to invert or flip materials for processing or inspection purposes. Consistent maintenance checks are crucial to uphold the functionality, alignment, and safety features of upset conveyors.
Upset dies – These are the tools used in the upset forging process. These are the specialized tools which capture the work-piece and control the deformation.
Upset distance – It is the total loss of axial length of the work-pieces from the initial contact to the completion of the weld. In flash welding, the upset distance is equal to the platen movement from the end of flash time to the end of upset.
Upset forging – It is also known as upsetter forging or heading. It is a metal forming process which increases the diameter of a metal work-piece by compressing its length. This is achieved by heating the metal and then forcing it through a die to reduce its length and expand its diameter. It is one of the most common methods of forging used today.
Upset pressing – It is the pressing of a powder compact in several stages, which results in an increase in the cross-sectional area of the part prior to its ejection.
Upsetter – It is a horizontal mechanical press which is used to make parts from bar stock or tubing by upset forging, piercing, bending, or otherwise forming in dies. It is also known as a header.
Upsetting – It is the working of metal so that the cross-sectional area of a portion or all of the stock is increased.
Upsetting process – It is a deformation process where a work-piece, typically a rod or billet, is compressed to shorten its length while increasing its diameter. This process is normally used in forging, especially for mass-producing components like bolts, screws, and engine valves.
Upsetting ratio – It is the ratio of the initial billet length to the initial billet diameter. It is a crucial factor in determining the feasibility and potential issues like buckling during the upsetting process. Specifically, it is the ratio of the length of the stock which is to be upset to the initial diameter of the stock.
Upset welding (UW) – It is a resistance welding process utilizing both heat and deformation to form a weld. The heat is produced by resistance to the flow of electrical current at the interface of the abutting surfaces to be joined. The deformation results from force on the joint in combination with softening from the electrical resistance heat. Upset welding typically results in solid-state welds (no melting at the joint). The deformation at the weld joint provides intimate contact between clean adjoining surfaces, allowing formation of strong metallurgical bonds. If any melting does occur during upset welding, the molten metal is typically extruded out of the weld joint area. A wide variety of shapes and materials can be joined using upset welding in either a single-pulse or continuous mode. Wire, bar, strip, and piping can be joined end to end with a single pulse of welding current. Seams on pipe or tubing can be joined using continuous upset welding by feeding a coiled strip into a set of forming rolls, resistance heating the edges with wheel electrodes, and applying a force to upset the edges together. Upset welds have similar characteristics to inertia friction welds, which are also solid-state welds. The amount of deformation is normally less for upset welds, and the deformation can be more precisely controlled using upset welding.
Upstream – It is the direction opposite to the material flow within a conveyor system. Maintenance checks in the upstream section are essential to detect and address issues which can impede the smooth movement of materials downstream.
Uptake – It is the duct used to convey the spent combustion gases from the boiler to the stack or chimney. It is also known as the flue vent and breeching.
Uptakes – They collect hot dirty blast furnace gas from the top of the furnace. They are four in numbers and send the collected gas to dust catcher through downcomer.
Upwelling – It is the upward movement of cold bottom water in the sea, which occurs when winds or currents displace the lighter surface water. The zones of upwelling are highly productive.
Uraninite – It is also known as pitchblende. It is a radioactive, uranium-rich mineral and ore with a chemical composition which is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the uranium causes the mineral to contain oxides of lead and trace quantities of helium.
Uranium (U) – It is a chemical element having atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays, normally by emitting an alpha particle. The half-life of this decay varies between 159,200 years and 4.5 billion years for different isotopes. Uranium is a moderately strong and ductile metal which can be cast, formed, and welded by a variety of standard methods. It is used in non-nuclear applications mainly because of its very high density (19.1 grams per cubic centimeter, 68 % higher than lead). Uranium is frequently selected over other very dense metals since it is easier to cast and / or fabricate than the refractory metal tungsten and much less costly than such precious metals as gold and platinum. Typical non-nuclear applications for uranium and uranium alloys include radiation shields, counterweights, and armour-piercing kinetic energy penetrators. Natural uranium contains around 0.7 % of the fissionable isotope U-235 and 99.3 % U-238. Ore of this isotopic ratio is processed by mineral beneficiation and chemical procedures to produce uranium hexa-fluoride (UF6). Isotopic separation is performed at this stage. This produces both enriched uranium hexa-fluoride, which contains more than the natural isotopic abundance of U-235 and is subsequently processed and used for nuclear applications, and depleted uranium hexa-fluoride, which typically contains 0.2 % U-235. Access to enriched uranium hexa-fluoride is tightly controlled, but depleted material can be used for industrial applications. The uranium hexa-fluoride is reduced to uranium tetra-fluoride (UF4), normally called green salt, by chemical reaction with hydrogen. The uranium tetra-fluoride is then reduced with magnesium or calcium in a closed vessel at high temperature, producing 150 kilograms to 500 kilograms ingots of metallic uranium normally referred to as derbies. These derbies are typically vacuum induction remelted and cast into the shapes needed for engineering components or for subsequent mechanical working. Alloying elements can also be added during this melting step. Ingot breakdown and primary fabrication processes, such as forging, rolling, and extruding, can be readily carried out between 550 deg C and 640 deg C or between 800 deg C and 900 deg C. The 650 deg C to 780 C range is avoided since cracking normally occurs at these temperatures. Secondary fabrication processes such as rolling, swaging, and straightening are normally done between room temperature and 500 deg C. Following heat treatment, machining to final dimensions can be carried out by majority of the conventional cutting and grinding techniques, but uranium and its alloys are normally considered difficult to machine. Hence, special tools and conditions are to be used.
Uranium carbide (UC) – It is a hard, refractory ceramic material composed of uranium and carbon. It is a type of carbide, and several forms exist, including UC, UC2, and U2C3. Uranium carbide is known for its high thermal conductivity and potential as a nuclear fuel.
Uranium di-oxide (UO2) – It is also known as urania. It is a black, crystalline compound of uranium and oxygen. It is a key component of nuclear fuel rods and is used in ceramics and pigments. Uranium di-oxide is a naturally occurring mineral, found in ores like pitchblende, and has a fluorite-type crystal structure.
Uranium nitride (UN) – IT is a nitride of uranium, specifically uranium mono-nitride (UN). It is a ceramic material used as a potential nuclear fuel, offering advantages like high thermal conductivity and uranium density. The word ‘nitride’ refers to a compound where nitrogen has a -3 oxidation state and is bonded to a metal, in this case, uranium.
Uranyl – It is the chemical name designating the (UO2)2+ group and compounds containing this group.
Urea – It is also called carbamide since it is a diamide of carbonic acid. It is an organic compound with chemical formula CO(NH2)2. This amide has two amino groups (–NH2) joined by a carbonyl functional group (–C(=O)–). It is hence the simplest amide of carbamic acid. Urea is a highly concentrated, solid, nitrogenous fertilizer, containing 46 % nitrogen. It is completely soluble in water hence nitrogen is easily available to crops. It contains nitrogen in a milder form which changes to ammoniacal forms and is retrieved by soil colloids for longer duration. Urea is available in granular form. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. Hence, it has a low transportation cost per unit of nitrogen nutrient. The most common impurity of synthetic urea is biuret, which impairs plant growth. Urea breaks down in the soil to give ammonium ions (NH4+). The ammonium is taken up by the plant through its roots. In some soils, the ammonium is oxidized by bacteria to give nitrate (NO3-), which is also a nitrogen-rich plant nutrient. The loss of nitrogenous compounds to the atmosphere and runoff is wasteful and environmentally damaging so urea is sometimes modified to improve the efficiency of its agricultural use.
Urethane – It can refer to (i) ethyl carbamate, a chemical compound which is an ester of carbamic acid, (ii) polyurethane, a polymer composed of a chain of organic units joined by carbamate (urethane) links, and (iii) carbamate, an organic compound derived from carbamic acid. Urethane is a versatile material normally used in conveyor components. It is known for its resilience, abrasion resistance, and chemical stability. Periodic assessments are necessary to ensure the integrity and functionality of urethane-based parts in the conveyor system.
Urethane lagging – It is the application of a layer of urethane material to pulley surfaces to enhance grip and reduce slipping with the conveyor belt. Regular inspections are crucial to maintain the effectiveness of urethane lagging, preventing issues like belt slippage.
Urethane plastics – These are plastics based on resins made by condensation of organic iso-cyanates with compounds or resins which contain hydroxyl groups. The resin is furnished as two component liquid monomers or prepolymers which are mixed in the field immediately before application. A great variety of materials are available, depending upon the monomers used in the prepolymers, polyols, and the type of diisocyanate used. These plastics are extremely abrasion and impact resistant.
U-section – It is also called C-section, or U-channel. It is a structural steel shape characterized by its ‘U’ shape, with a flat back and two parallel flanges extending outwards. In the normal series, the flanges with tapered internal faces have a maximum width of ‘0.5 x height + 25 mm’. There are U-sections which are thinner or thicker than the normal sections, and sections with parallel flanges. These sections are normally used in construction and manufacturing for load-bearing and non-load-bearing applications.
U-section dies – U-sections can be formed with simple radius dies by the bottoming method or with spring-loaded pad dies. In both cases, a second stroke with flat dies can be used to compensate for spring-back.
Used oil – It refers to any oil, whether refined from crude oil or synthetic, which has been used and, as a result of its use, has become contaminated with physical or chemical impurities. These impurities can include metal shavings, dirt, water, or chemicals, which affect the oil’s performance and make it unsuitable for its original purpose.
Use factor – It is the ratio of hours in operation to the total hours in that period.
Useful volume – It is the inner volume of the blast furnace between a plane through the centre-line of the tap hole and the stock-line level.
User-friendly interface – It is one which is designed to be intuitive, easy to understand, and navigate, ensuring users can complete tasks efficiently and without confusion. It prioritizes clarity, consistency, and simplicity to maximize usability and minimize user effort. Normally, the goal of user-friendly interface design is to produce a user interface which makes it easy, efficient, and enjoyable to operate an equipment in the way which produces the desired result (i.e. maximum usability). This normally means that the operator needs to provide minimal input to achieve the desired output, and also that the equipment minimizes undesired outputs to the user. User-friendly interfaces are composed of one or more layers, including a human–machine interface (HMI) which typically interfaces machines with physical input hardware (such as keyboard or mouse) and output hardware (such as computer monitor). A device which that implements an HMI is called a human interface device (HID).
Utilities – The term refers to the essential services and infrastructure which are necessary for a manufacturing plant to operate and produce goods. These include things like electricity, water, natural gas, compressed air, steam, and waste management. Utilities are not just a background service, but they are crucial for the availability, stability, and quality of manufacturing processes.
Utility cost – It is the cost incurred because of the consumption of power, water, utility gases, compressed air, and process steam etc. This cost contributes substantially to the production cost. In power intensive industries, power cost is not included under utility cost. It forms part of energy cost.
Utility flow diagram (UFD) – It is a special type of process flow diagram. It is a schematic representation of the energy utility systems within a process plant, showing all lines and other graphic means needed for the representation of transport, distribution, and collection of forms of energy. In a utility flow diagram, process equipment can be represented by boxes with inscriptions and with utility connections. The graphical symbols represent equipment and the lines represent flows of mass, energy, or energy carriers.
Utility frequency – It is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to an end-user. In majority of the countries of the world the utility frequency is standardized at 50 hertz, although in the Americas and parts of Asia it is typically 60 hertz.
Utility metering – It is the process of measuring and recording the consumption of electricity, water, or gas delivered by a utility organization to a customer. It involves using specialized devices called utility meters to quantify the resources used, which is then used to generate bills for the customer. It involves the use of meters provided by utilities to measure consumption.
Utility pole – It is a columnar structure which carries wires for electrical power distribution, cable television, telephone or similar services.
U-trough – It is a conveyor configuration resembling the shape of the letter ‘U’, normally used for handling bulk materials. Routine checks are essential to ensure the structural integrity, alignment, and material flow efficiency of U-trough conveyors.
UV stabilizers – These are chemicals added to paint to absorb the ultraviolet radiation present in sunlight. Ultra-violet radiation decomposes the polymer molecules in a paint film, and hence UV stabilizers are used to prolong paint life.
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