Dictionary of Engineering

a: Category : electricity(see ampere)
a axis: Category : mechanical engineering; The angle that specifies the rotation of a machine tool about the x axis.
A block: Category : civil engineering; A hollow concrete masonry block with one end closed and the other open and with a web between, so that when the block is laid in a wall two cells are produced.
A frame: Category : building construction engineering; A dwelling whose main frames are in the shape of the letter A.Two poles supported in an upright position by braces or guys and used for lifting equipment. Also known as double mast.
A size: Category : engineering; One of a series of sizes to which trimmed paper and board are manufactured, for size AOf a sheet of paper, the dimensions 8.5 inches by 11 inches (216 millimeters by 279 millimeters).
abandon: Category : engineering; To stop drilling and remove the drill rig from the site of a borehole before the intended depth or target is reached.
abat-jour: Category : building construction; A device that is used to deflect daylight downward as it streams through a window.
abattoir: Category : industrial engineering; A building in which cattle or other animals are slaughtered.
abat-vent: Category : building construction; A series of sloping boards or metal strips, or some similar contrivance, to break the force of wind without being an obstruction to the passage of air or sound, as in a louver or chimney cowl.
ablatograph: Category : engineering; An instrument that records ablation by measuring the distance a snow or ice surface falls during the observation period.
abnormal reading: Category : industrial engineering(see abnormal time)
abnormal time: Category : industrial engineering; During a time study, an elapsed time for any element which is excessively longer or shorter than the median of the elapsed times. Also known as abnormal reading.
abort branch: Category : control systems; A branching instruction in the program controlling a robot that causes a test to be performed on whether the tool-center point is properly positioned, and to reposition it if it drifts out of the acceptable range.
Abrams' law: Category : civil engineering; In concrete materials, for a mixture of workable consistency the strength of concrete is determined by the ratio of water to cement.
abrasion test: Category : mechanical engineering; The measurement of abrasion resistance, usually by the weighing of a material sample before and after subjecting it to a known abrasive stress throughout a known time period, or by reflectance or surface finish comparisons, or by dimensional comparisons.
abrasive belt: Category : mechanical engineering; A cloth, leather, or paper band impregnated with grit and rotated as an endless loop to abrade materials through continuous friction.
abrasive blasting: Category : mechanical engineering; The cleaning or finishing of surfaces by the use of an abrasive entrained in a blast of air.
abrasive cloth: Category : mechanical engineering; Tough cloth to whose surface an abrasive such as sand or emery has been bonded for use in grinding or polishing.
abrasive cone: Category : mechanical engineering; An abrasive sintered or shaped into a solid cone to be rotated by an arbor for abrasive machining.
abrasive disk: Category : mechanical engineering; An abrasive sintered or shaped into a disk to be rotated by an arbor for abrasive machining.
abrasive jet cleaning: Category : engineering; The removal of dirt from a solid by a gas or liquid jet carrying abrasives to ablate the surface.
abrasive machining: Category : mechanical engineering; Grinding, drilling, shaping, or polishing by abrasion.
abreast milling: Category : mechanical engineering; A milling method in which parts are placed in a row parallel to the axis of the cutting tool and are milled simultaneously.
abreuvoir: Category : civil engineering; A space between stones in masonry to be filled with mortar.
ABS: Category : mechanical engineering(see antilock braking system)
absolute altimeter: Category : engineering; An instrument which employs radio, sonic, or capacitive technology to produce on its indicator the measurement of distance from the aircraft to the terrain below. Also known as terrain-clearance indicator.
absolute altitude: Category : engineering; Altitude above the actual surface, either land or water, of a planet or natural satellite.
absolute block system: Category : civil engineering; A block system in which only a single railroad train is permitted within a block section during a given period of time.
absolute blocking: Category : civil engineering; A control arrangement for rail traffic in which a track is divided into sections or blocks upon which a train may not enter until the preceding train has left.
absolute efficiency: Category : engineering acoustics; The ratio of the power output of an electroacoustic transducer, under specified conditions, to the power output of an ideal electroacoustic transducer.
absolute expansion: Category : thermodynamics; The true expansion of a liquid with temperature, as calculated when the expansion of the container in which the volume of the liquid is measured is taken into account, in contrast with apparent expansion.
absolute instrument: Category : engineering; An instrument which measures a quantity (such as pressure or temperature) in absolute units by means of simple physical measurements on the instrument.
absolute magnetometer: Category : engineering; An instrument used to measure the intensity of a magnetic field without reference to other magnetic instruments.
absolute pressure gage: Category : engineering; A device that measures the pressure exerted by a fluid relative to a perfect vacuum, used to measure pressures very close to a perfect vacuum.
absolute pressure transducer: Category : engineering; A device that responds to absolute pressure as the input and provides a measurable output of a nature different than but proportional to absolute pressure.
absolute scale: Category : thermodynamics(see absolute temperature scale)
absolute specific gravity: Category : mechanics; The ratio of the weight of a given volume of a substance in a vacuum at a given temperature to the weight of an equal volume of water in a vacuum at a given temperature.
absolute stop: Category : civil engineering; A railway signal which indicates that the train must make a full stop and not proceed until there is a change in the signal. Also known as stop and stay.
absolute temperature scale: Category : thermodynamics; A scale with which temperatures are measured relative to absolute zero. Also known as absolute scale.
absolute volume: Category : engineering; The total volume of the particles in a granular material, including both permeable and impermeable voids but excluding spaces between particles.
absolute weighing: Category : engineering; Determination of the mass of a sample and expressing its value in units, fractions, and multiples of the mass of the prototype of the international kilogram.
absolute zero: Category : thermodynamics; The temperature of -273.16°C, or -459.69°F, or 0 K, thought to be the temperature at which molecular motion vanishes and a body would have no heat energy.
absorber capacity: Category : chemical engineering; During natural gas processing, the maximum volume of the gas that can be processed through an absorber without alteration of specified operating conditions.
absorber plate: Category : engineering; A part of a flat-plate solar collector that provides a surface for absorbing incident solar radiation.
absorbing boom: Category : civil engineering; A device that floats on the water and is used to stop the spread of an oil spill and aid in its removal.
absorbing well: Category : civil engineering; A shaft that permits water to drain through an impermeable stratum to a permeable stratum.
absorption bed: Category : civil engineering; A sizable pit containing coarse aggregate about a distribution pipe system, absorbs the effluent of a septic tank.
absorption column: Category : engineering(see absorption tower)
absorption cycle: Category : mechanical engineering; In refrigeration, the process whereby a circulating refrigerant, for example, ammonia, is evaporated by heat from an aqueous solution at elevated pressure and subsequently reabsorbed at low pressure, displacing the need for a compressor.
absorption dynamometer: Category : engineering; A device for measuring mechanical forces or power in which the mechanical energy input is absorbed by friction or electrical resistance.
absorption field: Category : civil engineering; Trenches containing coarse aggregate about distribution pipes permitting septic-tank effluent to seep into surrounding soil. Also known as disposal field.
absorption hygrometer: Category : engineering; An instrument with which the water vapor content of the atmosphere is measured by means of the absorption of vapor by a hygroscopic chemical.
absorption loss: Category : civil engineering; The quantity of water that is lost during the initial filling of a reservoir because of absorption by soil and rocks.
absorption meter: Category : engineering; An instrument designed to measure the amount of light transmitted through a transparent substance, using a photocell or other light detector.
absorption number: Category : engineering; A dimensionless group used in the field of gas absorption in a wetted-wall column, represents the liquid side mass-transfer coefficient.
absorption plant: Category : chemical engineering; A facility to recover the condensable portion of natural or refinery gas.
absorption process: Category : chemical engineering; A method in which light oil is introduced into an absorption tower so that it absorbs the gasoline in the rising wet gas, the light oil is then distilled to separate the gasoline.
absorption refrigeration: Category : mechanical engineering; Refrigeration in which cooling is effected by the expansion of liquid ammonia into gas and absorption of the gas by water, the ammonia is reused after the water evaporates.
absorption system: Category : mechanical engineering; A refrigeration system in which the refrigerant gas in the evaporator is taken up by an absorber and is then, with the application of heat, released in a generator.
absorption tower: Category : engineering; A vertical tube in which a rising gas is partially absorbed by a liquid in the form of falling droplets. Also known as absorption column.
absorption trench: Category : civil engineering; A trench containing coarse aggregate about a distribution tile pipe through which septic-tank effluent may move beneath earth.
absorption-emission pyrometer: Category : engineering; A thermometer for determining gas temperature from measurement of the radiation emitted by a calibrated reference source before and after this radiation has passed through and been partially absorbed by the gas.
absorptivity: Category : thermodynamics; The ratio of the radiation absorbed by a surface to the total radiation incident on the surface.
Abt track: Category : civil engineering; One of the cogged rails used for railroad tracking in mountains and so arranged that the cogs are not opposite one another on any pair of rails.
abutment: Category : civil engineering; A surface or mass provided to withstand thrust, for example, end supports of an arch or a bridge.
abutting joint: Category : design engineering; A joint which connects two pieces of wood in such a way that the direction of the grain in one piece is angled (usually at 90°) with respect to the grain in the other.
abutting tenons: Category : design engineering; Two tenons inserted into a common mortise from opposite sides so that they contact.
ac: Category : electricity(see alternating current)
accelerated aging: Category : engineering; Hastening the deterioration of a product by a laboratory procedure in order to determine long-range storage and use characteristics.
accelerated life test: Category : engineering; Operation of a device, circuit, or system above maximum ratings to produce premature failure, used to estimate normal operating life.
accelerated weathering: Category : engineering; A laboratory test used to determine, in a short period of time, the resistance of a paint film or other exposed surface to weathering.
accelerating incentive: Category : industrial engineering(see differential piece-rate system)
acceleration: Category : mechanics; The rate of change of velocity with respect to time.
acceleration analysis: Category : mechanical engineering; A mathematical technique, often done graphically, by which accelerations of parts of a mechanism are determined.
acceleration measurement: Category : mechanics; The technique of determining the magnitude and direction of acceleration, including translational and angular acceleration.
acceleration of free fall: Category : mechanics(see acceleration of gravity)
acceleration of gravity: Category : mechanics; The acceleration imparted to bodies by the attractive force of the earth, has an international standard value of 980.665 cm/s² but varies with latitude and elevation. Also known as acceleration of free fall, apparent gravity.
acceleration signature: Category : industrial engineering; A printed record that shows the pattern of acceleration and deceleration of an anatomical reference point in the performance of a task.
acceleration tolerance: Category : engineering; The degree to which personnel or equipment withstands acceleration.
acceleration-error constant: Category : control systems; The ratio of the acceleration of a controlled variable of a servomechanism to the actuating error when the actuating error is constant.
accelerator: Category : mechanical engineering; A device for varying the speed of an automotive vehicle by varying the supply of fuel.
accelerator jet: Category : mechanical engineering; The jet through which the fuel is injected into the incoming air in the carburetor of an automotive vehicle with rapid demand for increased power output.
accelerator linkage: Category : mechanical engineering; The linkage connecting the accelerator pedal of an automotive vehicle to the carburetor throttle valve or fuel injection control.
accelerator pedal: Category : mechanical engineering; A pedal that operates the carburetor throttle valve or fuel injection control of an automotive vehicle.
accelerator pump: Category : mechanical engineering; A small cylinder and piston controlled by the throttle of an automotive vehicle so as to provide an enriched air-fuel mixture during acceleration.
accelerogram: Category : engineering; A record made by an accelerograph.
accelerograph: Category : engineering; An accelerometer having provisions for recording the acceleration of a point on the earth during an earthquake or for recording any other type of acceleration.
accelerometer: Category : engineering; An instrument which measures acceleration or gravitational force capable of imparting acceleration.
accelerometry: Category : industrial engineering; The quantitative determination of acceleration and deceleration in the entire human body or a part of the body in the performance of a task.
accent lighting: Category : civil engineering; Directional lighting which highlights an object or attracts attention to a particular area.
acceptability: Category : engineering; State or condition of meeting minimum standards for use, as applied to methods, equipment, or consumable products.
acceptable quality level: Category : industrial engineering; The maximum percentage of defects that has been determined tolerable as a process average for a sampling plan during inspection or test of a product with respect to economic and functional requirements of the item. Abbreviated AQL.
acceptable reliability level: Category : industrial engineering; The required level of reliability for a part, system, device, and so forth, may be expressed in a variety of terms, for example, number of failures allowable in 1000 hours of operating life. Abbreviated ARL.
acceptance criteria: Category : industrial engineering; Standards of judging the acceptability of manufactured items.
acceptance number: Category : industrial engineering; The maximum allowable number of defective pieces in a sample of specified size.
acceptance sampling: Category : industrial engineering; Taking a sample from a batch of material to inspect for determining whether the entire lot will be accepted or rejected.
acceptance test: Category : industrial engineering; A test used to determine conformance of a product to design specifications, as a basis for its acceptance.
acceptor: Category : chemical engineering; A calcined carbonate used to absorb the carbon dioxide evolved during a coal gasification process.
access: Category : civil engineering; Freedom, ability, or the legal right to pass without obstruction from a given point on earth to some other objective, such as the sea or a public highway.
access door: Category : building construction; A provision for access to concealed plumbing or other equipment without disturbing the wall or fixtures.
access flooring: Category : civil engineering(see raised flooring)
access hole: Category : engineering(see manhole)
access road: Category : civil engineering; A route, usually paved, that enables vehicles to reach a designated facility expeditiously.
access tunnel: Category : civil engineering; A tunnel provided for an access road.
accessory: Category : mechanical engineering; A part, subassembly, or assembly that contributes to the effectiveness of a piece of equipment without changing its basic function, may be used for testing, adjusting, calibrating, recording, or other purposes.
accident frequency rate: Category : industrial engineering; The number of all disabling injuries per million worker-hours of exposure.
accident severity rate: Category : industrial engineering; The number of worker-days lost as a result of disabling injuries per thousand worker-hours of exposure.
accident-cause code: Category : industrial engineering; Sponsored by the American Standards Association, the code that classifies accidents under eight defective working conditions and nine improper working practices.
accommodation: Category : control systems; Any alteration in a robot's motion in response to the robot's environment, it may be active or passive.
accordion door: Category : building construction; A door that folds and unfolds like an accordion when it is opened and closed.
accordion partition: Category : building construction; A movable, fabric-faced partition which is fitted into an overhead track and folds like an accordion.
accordion roller conveyor: Category : mechanical engineering; A conveyor with a flexible latticed frame which permits variation in length.
accretion: Category : civil engineering; Artificial buildup of land due to the construction of a groin, breakwater, dam, or beach fill.
accumulated discrepancy: Category : engineering; The sum of the separate discrepancies which occur in the various steps of making a survey.
accumulative timing: Category : industrial engineering; A time-study method that allows direct reading of the time for each element of an operation by the use of two stopwatches which operate alternately.
accustomization: Category : engineering; The process of learning the techniques of living with a minimum of discomfort in an extreme or new environment.
acetate process: Category : chemical engineering; Acetylation of cellulose (wood pulp or cotton linters) with acetic acid or acetic anhydride and sulfuric acid catalyst to make cellulose acetate resin or fiber.
acetone-benzol process: Category : chemical engineering; A dewaxing process in petroleum refining, with acetone and benzol used as solvents.
acetylene cutting: Category : engineering(see oxyacetylene cutting)
acetylene generator: Category : engineering; A steel cylinder or tank that provides for controlled mixing of calcium carbide and water to generate acetylene.
acetylene torch: Category : engineering(see oxyacetylene torch)
acfm: Category : chemical engineering(see actual cubic feet per minute)
acid blowcase: Category : chemical engineering(see blowcase)
acid cleaning: Category : engineering; The use of circulating acid to remove dirt, scale, or other foreign matter from the interior of a pipe.
acid conductor: Category : chemical engineering; A vessel designed for refortification of hydrolyzed acid by heating and evaporation of water, or sometimes by distillation of water under partial vacuum.
acid egg: Category : chemical engineering(see blowcase)
acid gases: Category : chemical engineering; The hydrogen sulfide and carbon dioxide found in natural and refinery gases which, when combined with moisture, form corrosive acids, known as sour gases when hydrogen sulfide and mercaptans are present.
acid lining: Category : engineering; In steel production, a silica-brick lining used in furnaces.
acid number: Category : engineering; A number derived from a standard test indicating the acid or base composition of lubricating oils, it in no way indicates the corrosive attack of the used oil in service. Also known as corrosion number.
acid polishing: Category : engineering; The use of acids to polish a glass surface.
acid process: Category : chemical engineering; In paper manufacture, a pulp digestion process that uses an acidic reagent, for example, a bisulfite solution containing free sulfur dioxide.
acid recovery plant: Category : chemical engineering; In some refineries, a facility for separating sludge acid into acid oil, tar, and weak sulfuric acid, with provision for later reconcentration.
acid sludge: Category : chemical engineering; The residue left after treating petroleum oil with sulfuric acid for the removal of impurities.
acid soot: Category : engineering; Carbon particles that have absorbed acid fumes as a by-product of combustion, hydrochloric acid absorbed on carbon particulates is frequently the cause of metal corrosion in incineration.
acid treatment: Category : chemical engineering; A refining process in which unfinished petroleum products, such as gasoline, kerosine, and diesel oil, are contacted with sulfuric acid to improve their color, odor, and other properties.
aciding: Category : engineering; A light etching of a building surface of cast stone.
acid-water pollution: Category : engineering; Industrial wastewaters that are acidic, usually appears in effluent from the manufacture of chemicals, batteries, artificial and natural fiber, fermentation processes (beer), and mining.
Ackerman linkage: Category : mechanical engineering(see Ackerman steering gear)
acme screw thread: Category : design engineering; A standard thread having a profile angle of 29º and a flat crest, used on power screws in such devices as automobile jacks, presses, and lead screws on lathes. Also known as acme thread.
acme thread: Category : design engineering(see acme screw thread)
acoubuoy: Category : engineering; An acoustic listening device similar to a sonobuoy, used on land to form an electronic fence that will pick up sounds of enemy movements and transmit them to orbiting aircraft or land stations.
acoustic array: Category : engineering acoustics; A sound-transmitting or sound-receiving system whose elements are arranged to give desired directional characteristics.
acoustic center: Category : engineering acoustics; The center of the spherical sound waves radiating outward from an acoustic transducer.
acoustic clarifier: Category : engineering acoustics; System of cones loosely attached to the baffle of a loudspeaker and designed to vibrate and absorb energy during sudden loud sounds to suppress these sounds.
acoustic coupler: Category : engineering acoustics; A device used between the modem of a computer terminal and a standard telephone line to permit transmission of digital data in either direction without making direct connections.
acoustic delay: Category : engineering acoustics; A delay which is deliberately introduced in sound reproduction by having the sound travel a certain distance along a pipe before conversion into electric signals.
acoustic detection: Category : engineering; Determination of the profile of a geologic formation, an ocean layer, or some object in the ocean by measuring the reflection of sound waves off the object.
acoustic fatigue: Category : mechanics; The tendency of a material, such as a metal, to lose strength after acoustic stress.
acoustic feedback: Category : engineering acoustics; The reverberation of sound waves from a loudspeaker to a preceding part of an audio system, such as to the microphone, in such a manner as to reinforce, and distort, the original input. Also known as acoustic regeneration.
acoustic generator: Category : engineering acoustics; A transducer which converts electrical, mechanical, or other forms of energy into sound.
acoustic heat engine: Category : engineering; A device that transforms heat energy first into sound energy and then into electrical power, without the use of moving mechanical parts.
acoustic hologram: Category : engineering; The phase interference pattern, formed by acoustic beams, that is used in acoustical holography, when light is made to interact with this pattern, it forms an image of an object placed in one of the beams.
acoustic horn: Category : building construction(see horn)
acoustic jamming: Category : engineering acoustics; The deliberate radiation or reradiation of mechanical or electroacoustic signals with the objectives of obliterating or obscuring signals which the enemy is attempting to receive and of deterring enemy weapons systems.
acoustic labyrinth: Category : engineering acoustics; Special baffle arrangement used with a loudspeaker to prevent cavity resonance and to reinforce bass response.
acoustic line: Category : engineering acoustics; The acoustic equivalent of an electrical transmission line, involving baffles, labyrinths, or resonators placed at the rear of a loudspeaker and arranged to help reproduce the very low audio frequencies.
acoustic ocean-current meter: Category : engineering; An instrument that measures current flow in rivers and oceans by transmitting acoustic pulses in opposite directions parallel to the flow and measuring the difference in pulse travel times between transmitter-receiver pairs.
acoustic position reference system: Category : engineering; An acoustic system used in offshore oil drilling to provide continuous information on ship position with respect to an ocean-floor acoustic beacon transmitting an ultrasonic signal to three hydrophones on the bottom of the drilling ship.
acoustic radar: Category : engineering; Use of sound waves with radar techniques for remote probing of the lower atmosphere, up to heights of about 5000 feet (1500 meters), for measuring wind speed and direction, humidity, temperature inversions, and turbulence.
acoustic radiator: Category : engineering acoustics; A vibrating surface that produces sound waves, such as a loudspeaker cone or a headphone diaphragm.
acoustic radiometer: Category : engineering; An instrument for measuring sound intensity by determining the unidirectional steady-state pressure caused by the reflection or absorption of a sound wave at a boundary.
acoustic ratio: Category : engineering acoustics; The ratio of the intensity of sound radiated directly from a source to the intensity of sound reverberating from the walls of an enclosure, at a given point in the enclosure.
acoustic reflex enclosure: Category : engineering acoustics; A loudspeaker cabinet designed with a port to allow a low-frequency contribution from the rear of the speaker cone to be radiated forward.
acoustic regeneration: Category : engineering acoustics(see acoustic feedback)
acoustic seal: Category : engineering acoustics; A joint between two parts to provide acoustical coupling with low losses of energy, such as between an earphone and the human ear.
acoustic signature: Category : engineering; In acoustic detection, the profile characteristic of a particular object or class of objects, such as a school of fish or a specific ocean-bottom formation.
acoustic spectrograph: Category : engineering; A spectrograph used with sound waves of various frequencies to study the transmission and reflection properties of ocean thermal layers and marine life.
acoustic spectrometer: Category : engineering acoustics; An instrument that measures the intensities of the various frequency components of a complex sound wave. Also known as audio spectrometer.
acoustic strain gage: Category : engineering; An instrument used for measuring structural strains, consists of a length of fine wire mounted so its tension varies with strain, the wire is plucked with an electromagnetic device, and the resulting frequency of vibration is measured to determine the amo
acoustic theodolite: Category : engineering; An instrument that uses sound waves to provide a continuous vertical profile of ocean currents at a specific location.
acoustic transducer: Category : engineering acoustics; A device that converts acoustic energy to electrical or mechanical energy, such as a microphone or phonograph pickup.
acoustic transformer: Category : engineering acoustics; A device, such as a horn or megaphone, for increasing the efficiency of sound radiation.
acoustic treatment: Category : building construction; The use of sound-absorbing materials to give a room a desired degree of freedom from echo and reverberation.
acoustic well logging: Category : engineering; A ground exploration method that uses a high-energy sound source and a receiver, both underground.
acoustical ceiling: Category : building construction; A ceiling covered with or built of material with special acoustical properties.
acoustical ceiling system: Category : building construction; A system for the structural support of an acoustical ceiling, lighting and air diffusers may be included as part of the system.
acoustical door: Category : building construction; A solid door with gasketing along the top and sides, and usually an automatic door bottom, designed to reduce noise transmission.
acoustical model: Category : civil engineering; A model used to investigate certain acoustical properties of an auditorium or room such as sound pressure distribution, sound-ray paths, and focusing effects.
acoustical treatment: Category : civil engineering; That part of building planning that is designed to provide a proper acoustical environment, includes the use of acoustical material.
acoustic-wave-based sensor: Category : engineering; A device that employs a surface acoustic wave, a thickness-shear-mode resonance (a resonant oscillation of a thin plate of material), or other type of acoustic wave to measure the physical properties of a thin film or liquid layer or, in combination with
acoustoelectronics: Category : engineering acoustics; The branch of electronics that involves use of acoustic waves at microwave frequencies (above 500 megahertz), traveling on or in piezoelectric or other solid substrates. Also known as pretersonics.
acquisition: Category : engineering; The process of pointing an antenna or a telescope so that it is properly oriented to allow gathering of tracking or telemetry data from a satellite or space probe.
acquisition and tracking radar: Category : engineering; A radar set capable of locking onto a received signal and tracking the object emitting the signal, the radar may be airborne or on the ground.
acre: Category : mechanics; A unit of area, equal to 43,560 square feet, or to 4046.8564224 square meters.
acrometer: Category : engineering; An instrument to measure the density of oils.
actinogram: Category : engineering; The record of heat from a source, such as the sun, as detected by a recording actinometer.
actinograph: Category : engineering; A recording actinometer.
actinometer: Category : engineering; Any instrument used to measure the intensity of radiant energy, particularly that of the sun.
action: Category : mechanics; An integral associated with the trajectory of a system in configuration space, equal to the sum of the integrals of the generalized momenta of the system over their canonically conjugate coordinates. Also known as phase integral.
activated sludge: Category : civil engineering; A semiliquid mass removed from the liquid flow of sewage and subjected to aeration and aerobic microbial action, the end product is dark to golden brown, partially decomposed, granular, and flocculent, and has an earthy odor when fresh.
activated-sludge effluent: Category : civil engineering; The liquid from the activated-sludge treatment that is further processed by chlorination or by oxidation.
activated-sludge process: Category : civil engineering; A sewage treatment process in which the sludge in the secondary stage is put into aeration tanks to facilitate aerobic decomposition by microorganisms, the sludge and supernatant liquor are separated in a settling tank, the supernatant liquor or effluent
active accommodation: Category : control systems; The alteration of preprogrammed robotic motions by the integrated effects of sensors, controllers, and the robotic motion itself.
active detection system: Category : engineering; A guidance system which emits energy as a means of detection, for example, sonar and radar.
active earth pressure: Category : civil engineering; The horizontal pressure that an earth mass exerts on a wall.
active illumination: Category : engineering; Lighting whose direction, intensity, and pattern are controlled by commands or signals.
active infrared detection system: Category : engineering; An infrared detection system in which a beam of infrared rays is transmitted toward possible targets, and rays reflected from a target are detected.
active leaf: Category : building construction; In a door with two leaves, the leaf which carries the latching or locking mechanism. Also known as active door.
active sludge: Category : civil engineering; A sludge rich in destructive bacteria used to break down raw sewage.
active solar system: Category : mechanical engineering; A solar heating or cooling system that operates by mechanical means, such as motors, pumps, or valves.
active sonar: Category : engineering; A system consisting of one or more transducers to send and receive sound, equipment for the generation and detection of the electrical impulses to and from the transducer, and a display or recorder system for the observation of the received signals.
active system: Category : engineering; In radio and radar, a system that requires transmitting equipment, such as a beacon or transponder.
active vibration suppression: Category : mechanical engineering; The prevention of undesirable vibration by techniques involving feedback control of the vibratory motion, whereby the forces designed to reduce the vibration depend on the system displacements and velocities.
active-cord mechanism: Category : mechanical engineering; A slender, chainlike grouping of joints and links that makes active and flexible winding motions under the control of actuators attached along its body.
activity: Category : systems engineering; The representation in a PERT or critical-path-method network of a task that takes up both time and resources and whose performance is necessary for the system to move from one event to the next.
activity chart: Category : industrial engineering; A tabular presentation of a series of operations of a process plotted against a time scale.
activity duration: Category : systems engineering; In critical-path-method terminology, the estimated amount of time required to complete an activity.
activity sampling: Category : industrial engineering(see work sampling)
actual cost: Category : industrial engineering; Cost determined by an allocation of cost factors recorded during production.
actual cubic feet per minute: Category : chemical engineering; A measure of the volume of gas at operating temperature and pressure, as distinct from volume of gas at standard temperature and pressure. Abbreviated acfm.
actual horsepower: Category : mechanical engineering(see actual power)
actual power: Category : mechanical engineering; The power delivered at the output shaft of a source of power. Also known as actual horsepower.
actual relative movement: Category : civil engineering(see slip)
actual time: Category : industrial engineering; Time taken by a worker to perform a given task.
actuate: Category : mechanical engineering; To put into motion or mechanical action, as by an actuator.
actuated roller switch: Category : mechanical engineering; A centrifugal sequence-control switch that is placed in contact with a belt conveyor, immediately preceding the conveyor which it controls.
actuating system: Category : control systems; An electric, hydraulic, or other system that supplies and transmits energy for the operation of other mechanisms or systems.
ada mud: Category : engineering; A conditioning material added to drilling mud to obtain satisfactory cores and samples of formations.
adamantine drill: Category : mechanical engineering; A core drill with hardened steel shot pellets that revolve under the rim of the rotating tube, employed in rotary drilling in very hard ground.
Adam's catalyst: Category : chemical engineering; Finely divided plantinum(IV) oxide, made by fusing hexachloroplatinic(IV) acid with NaNO₃.
adapter: Category : engineering; A device used to make electrical or mechanical connections between items not originally intended for use together.
adaptive branch: Category : control systems; A branch instruction in the computer program controlling a robot that may lead the robot to execute a series of instructions, depending on external conditions.
adaptive control: Category : control systems; A control method in which one or more parameters are sensed and used to vary the feedback control signals in order to satisfy the performance criteria.
adaptive robot: Category : control systems; A robot that can alter its responses according to changes in the environment.
adaptive structure: Category : engineering; A structure whose geometric and inherent structural characteristics can be changed beneficially in response to external stimulation by either remote commands or automatic means.
adaptive system: Category : systems engineering; A system that can change itself in response to changes in its environment in such a way that its performance improves through a continuing interaction with its surroundings.
adaptive-control function: Category : control systems; That level in the functional decomposition of a large-scale control system which updates parameters of the optimizing control function to achieve a best fit to current plant behavior, and updates parameters of the direct control function to achieve good d
adaptometer: Category : engineering; An instrument that measures the lowest brightness of an extended area that can barely be detected by the eye.
addendum: Category : design engineering; The radial distance between two concentric circles on a gear, one being that whose radius extends to the top of a gear tooth (addendum circle) and the other being that which will roll without slipping on a circle on a mating gear (pitch line).
addendum circle: Category : design engineering; The circle on a gear passing through the tops of the teeth.
adding tape: Category : engineering; A surveyor's tape that is calibrated from 0 to 100 by full feet (or meters) in one direction, and has 1 additional foot (or meter) beyond the zero end which is subdivided in tenths or hundredths.
additive synthesis: Category : engineering acoustics; A method of synthesizing complex tones by adding together an appropriate number of simple sine waves at harmonically related frequencies.
adhesional work: Category : thermodynamics; The work required to separate a unit area of a surface at which two substances are in contact. Also known as work of adhesion.
adhesive bond: Category : mechanics; The forces such as dipole bonds which attract adhesives and base materials to each other.
adhesive bonding: Category : engineering; The fastening together of two or more solids by the use of glue, cement, or other adhesive.
adhesive strength: Category : engineering; The strength of an adhesive bond, usually measured as a force required to separate two objects of standard bonded area, by either shear or tensile stress.
adiabatic: Category : thermodynamics; Referring to any change in which there is no gain or loss of heat.
adiabatic compression: Category : thermodynamics; A reduction in volume of a substance without heat flow, in or out.
adiabatic cooling: Category : thermodynamics; A process in which the temperature of a system is reduced without any heat being exchanged between the system and its surroundings.
adiabatic curing: Category : engineering; The curing of concrete or mortar under conditions in which there is no loss or gain of heat.
adiabatic engine: Category : mechanical engineering; A heat engine or thermodynamic system in which there is no gain or loss of heat.
adiabatic envelope: Category : thermodynamics; A surface enclosing a thermodynamic system in an equilibrium which can be disturbed only by long-range forces or by motion of part of the envelope, intuitively, this means that no heat can flow through the surface.
adiabatic expansion: Category : thermodynamics; Increase in volume without heat flow, in or out.
adiabatic extrusion: Category : engineering; Forming plastic objects by energy produced by driving the plastic mass through an extruder without heat flow.
adiabatic process: Category : thermodynamics; Any thermodynamic procedure which takes place in a system without the exchange of heat with the surroundings.
adiabatic vaporization: Category : thermodynamics; Vaporization of a liquid with virtually no heat exchange between it and its surroundings.
adit: Category : civil engineering; An access tunnel used for excavation of the main tunnel.
adjustable base anchor: Category : building construction; An item which holds a doorframe above a finished floor.
adjustable parallels: Category : engineering; Wedge-shaped iron bars placed with the thin end of one on the thick end of the other, so that the top face of the upper and the bottom face of the lower remain parallel, but the distance between the two faces is adjustable, the bars can be locked in posit
adjustable square: Category : engineering; A try square with an arm that is at right angles to the ruler, the position of the arm can be changed to form an L or a T. Also known as double square.
adjustable wrench: Category : engineering; A wrench with one jaw which is fixed and another which is adjustable, the size is adjusted by a knurled screw.
adjusting: Category : engineering; In measurement technology, setting or compensating a measuring instrument or a weight in such a way that the indicated value deviates as little as possible from the actual value.
adjutage: Category : engineering; A tube attached to a container of liquid at an orifice to facilitate or regulate outflow.
admittance: Category : electricity; A measure of how readily alternating current will flow in a circuit, the reciprocal of impedance, it is expressed in siemens.
adobe construction: Category : building construction; Wall construction with sun-dried blocks of adobe soil.
ADP: Category : engineering(see automatic data processing)
ADR studio: Category : engineering acoustics; A sound-recording studio used in motion-picture and television production to allow an actor who did not intelligibly record his or her speech during the original filming or video recording to do so by watching himself or herself on the screen and repeatin
adsorption system: Category : mechanical engineering; A device that dehumidifies air by bringing it into contact with a solid adsorbing substance.
advance signal: Category : civil engineering; A signal in a block system up to which a train may proceed within a block that is not completely cleared.
advance slope grouting: Category : engineering; A grouting technique in which the front of the mass of grout is forced to move horizontally through preplaced aggregate.
advance slope method: Category : engineering; A method of concrete placement in which the face of the fresh concrete, which is not vertical, moves forward as the concrete is placed.
advanced programmatic risk analysis: Category : industrial engineering; A method for managing engineering programs with multiple projects and strict resource constraints which balances both technical and management risks.
advanced sewage treatment: Category : civil engineering(see tertiary sewage treatment)
adz: Category : design engineering; A cutting tool with a thin arched blade, sharpened on the concave side, at right angles on the handle, used for rough dressing of timber.
adz block: Category : mechanical engineering; The part of a machine for wood planing that carries the cutters.
aerated flow: Category : engineering; Flowing liquid in which gas is dispersed as fine bubbles throughout the liquid.
aeration tank: Category : engineering; A fluid-holding tank with provisions to aerate its contents by bubbling air or another gas through the liquid or by spraying the liquid into the air.
aerial cableway: Category : mechanical engineering(see aerial tramway)
aerial photogrammetry: Category : engineering; Use of aerial photographs to make accurate measurements in surveying and mapmaking.
aerial photographic reconnaissance: Category : engineering(see aerial photoreconnaissance)
aerial photography: Category : engineering; The making of photographs of the ground surface from an aircraft, spacecraft, or rocket. Also known as aerophotography.
aerial photoreconnaissance: Category : engineering; The obtaining of information by air photography, the three types are strategic, tactical, and survey-cartographic photoreconnaissance. Also known as aerial photographic reconnaissance.
aerial reconnaissance: Category : engineering; The collection of information by visual, electronic, or photographic means while aloft.
aerial ropeway: Category : mechanical engineering(see aerial tramway)
aerial spud: Category : mechanical engineering; A cable for moving and anchoring a dredge.
aerial survey: Category : engineering; A survey utilizing photographic, electronic, or other data obtained from an airborne station. Also known as aerosurvey, air survey.
aerial tramway: Category : mechanical engineering; A system for transporting bulk materials that consists of one or more cables supported by steel towers and is capable of carrying a traveling carriage from which loaded buckets can be lowered or raised. Also known as aerial cableway, aerial ropeway.
aeroballistics: Category : mechanics; The study of the interaction of projectiles or high-speed vehicles with the atmosphere.
aerobic digestion: Category : chemical engineering; Digestion of matter suspended or dissolved in waste by microorganisms under favorable conditions of oxygenation.
aerobic lagoon: Category : civil engineering; An aerated pond in which sewage solids are placed, and are decomposed by aerobic bacteria. Also known as aerobic pond.
aerobic pond: Category : civil engineering(see aerobic lagoon)
aerobic-anaerobic interface: Category : civil engineering; That point in bacterial action in the body of a sewage sludge or compost heap where both aerobic and anaerobic microorganisms participate, and the decomposition of the material goes no further.
aerobic-anaerobic lagoon: Category : civil engineering; A pond in which the solids from a sewage plant are placed in the lower layer, the solids are partially decomposed by anaerobic bacteria, while air or oxygen is bubbled through the upper layer to create an aerobic condition.
aerochlorination: Category : civil engineering; Treatment of sewage with compressed air and chlorine gas to remove fatty substances.
aerodrome: Category : civil engineering(see airport)
aerodynamic balance: Category : engineering; A balance used for the measurement of the forces exerted on the surfaces of instruments exposed to flowing air, frequently used in tests made on models in wind tunnels.
aerodynamic trajectory: Category : mechanics; A trajectory or part of a trajectory in which the missile or vehicle encounters sufficient air resistance to stabilize its flight or to modify its course significantly.
aeroelasticity: Category : mechanics; The deformation of structurally elastic bodies in response to aerodynamic loads.
aerofall mill: Category : mechanical engineering; A grinding mill of large diameter with either lumps of ore, pebbles, or steel balls as crushing bodies, the dry load is airswept to remove mesh material.
aerofilter: Category : civil engineering; A filter bed for sewage treatment consisting of coarse material and operated at high speed, often with recirculation.
aerograph: Category : engineering; Any self-recording instrument carried aloft by any means to obtain meteorological data.
aerometeorograph: Category : engineering; A self-recording instrument used on aircraft for the simultaneous recording of atmospheric pressure, temperature, and humidity.
aerometer: Category : engineering; An instrument to ascertain the weight or density of air or other gases.
aerophotography: Category : engineering(see aerial photography)
aerosol generator: Category : mechanical engineering; A mechanical means of producing a system of dispersed phase and dispersing medium, that is, an aerosol.
aerospace engineering: Category : engineering; Engineering pertaining to the design and construction of aircraft and space vehicles and of power units, and to the special problems of flight in both the earth's atmosphere and space, as in the flight of air vehicles and in the launching, guidance, and c
aerospace industry: Category : engineering; Industry concerned with the use of vehicles in both the earth's atmosphere and space.
aerostatic balance: Category : engineering; An instrument for weighing air.
aerosurvey: Category : engineering(see aerial survey)
aerotrain: Category : engineering; A train that is propelled by a fan jet engine and floats on a cushion of low-pressure air, traveling at speeds up to 267 miles (430 kilometers) per hour.
aesthesiometer: Category : engineering(see esthesiometer)
affreightment: Category : industrial engineering; The lease of a vessel for the transportation of goods.
after top dead center: Category : mechanical engineering; The position of the piston after reaching the top of its stroke in an automotive engine.
afterboil: Category : mechanical engineering; In an automotive engine, coolant boiling after the engine has stopped because of the inability of the engine at rest to dissipate excess heat.
afterburning: Category : mechanical engineering; Combustion in an internal combustion engine following the maximum pressure of explosion.
aftercondenser: Category : mechanical engineering; A condenser in the second stage of a two-stage ejector, used in steam power plants, refrigeration systems, and air conditioning systems.
aftercooler: Category : mechanical engineering; A heat exchanger which cools air that has been compressed, used on turbocharged engines.
aftercooling: Category : mechanical engineering; The cooling of a gas after its compression.
afterfilter: Category : mechanical engineering; In an air-conditioning system, a high-efficiency filter located near a terminal unit. Also known as final filter.
afterrunning: Category : mechanical engineering; In an automotive engine, continued operation of the engine after the ignition switch is turned off. Also known as dieseling, run-on.
agger: Category : civil engineering; A material used for road fill over low ground.
aggregate bin: Category : engineering; A structure designed for storing and dispensing dry granular construction materials such as sand, crushed stone, and gravel, usually has a hopperlike bottom that funnels the material to a gate under the structure.
aggregate interlock: Category : engineering; The projection of aggregate particles or portions thereof from one side of a joint or crack in concrete into recesses in the other side so as to effect load transfer in compression and shear, and to maintain mutual alignment.
aggregate production scheduling: Category : industrial engineering; A type of planning at a broad level without consideration of individual products and activities in order to develop a program of output that will meet future demand under given constraints.
aggressive carbon dioxide: Category : chemical engineering; The carbon dioxide dissolved in water in excess of the amount required to precipitate a specified concentration of calcium ions as calcium carbonate, used as a measure of the corrosivity and scaling properties of water.
agile manufacturing: Category : industrial engineering; Operations that can be rapidly reconfigured to satisfy changing market demands.
agitating speed: Category : mechanical engineering; The rate of rotation of the drum or blades of a truck mixer or other device used for agitation of mixed concrete.
agitating truck: Category : mechanical engineering; A vehicle carrying a drum or agitator body, in which freshly mixed concrete can be conveyed from the point of mixing to that of placing, the drum being rotated continuously to agitate the contents.
agitator: Category : mechanical engineering; A device for keeping liquids and solids in liquids in motion by mixing, stirring, or shaking.
agitator body: Category : mechanical engineering; A truck-mounted drum for transporting freshly mixed concrete, rotation of internal paddles or of the drum prevents the setting of the mixture prior to delivery.
agricultural pipe drain: Category : civil engineering; A system of porous or perforated pipes laid in a trench filled with gravel or the like, used for draining subsoil.
agricultural robot: Category : control systems; A robot used to pick and harvest farm products and fruits.
AGV: Category : industrial engineering(see automated guided vehicle)
aided tracking: Category : engineering; A system of radar-tracking a target signal in bearing, elevation, or range, or any combination of these variables, in which the rate of motion of the tracking equipment is machine-controlled in collaboration with an operator so as to minimize tracking err
aided-tracking mechanism: Category : engineering; A device consisting of a motor and variable-speed drive which provides a means of setting a desired tracking rate into a director or other fire-control instrument, so that the process of tracking is carried out automatically at the set rate until it is ch
aided-tracking ratio: Category : engineering; The ratio between the constant velocity of the aided-tracking mechanism and the velocity of the moving target.
aiguille: Category : engineering; A slender form of drill used for boring or drilling a blasthole in rock.
aiming circle: Category : engineering; An instrument for measuring angles in azimuth and elevation in connection with artillery firing and general topographic work, equipped with fine and coarse azimuth micrometers and a magnetic needle.
aiming screws: Category : mechanical engineering; On an automotive vehicle, spring-loaded screws designed to secure headlights to a support frame and permit aiming of the headlights in horizontal and vertical planes.
air: Category : mechanical engineering(see air-injection reactor)
air aspirator valve: Category : mechanical engineering; On certain automotive engines, a one-way valve installed on the exhaust manifold to allow air to enter the exhaust system, provides extra oxygen to convert carbon monoxide to carbon dioxide. Also known as gulp valve.
air bag: Category : mechanical engineering; An automotive vehicle passenger safety device consisting of a passive restraint in the form of a bag which is automatically inflated with gas to provide cushioned protection against the impact of a collision.
air belt: Category : mechanical engineering; The chamber which equalizes the pressure that is blasted into the cupola at the tuyeres.
air bind: Category : engineering; The presence of air in a conduit or pump which impedes passage of the liquid.
air bleeder: Category : mechanical engineering; A device, such as a needle valve, for removing air from a hydraulic system.
air brake: Category : mechanical engineering; An energy-conversion mechanism activated by air pressure and used to retard, stop, or hold a vehicle or, generally, any moving element.
air breaking: Category : engineering(see airblasting)
air bypass valve: Category : mechanical engineering; Also known as diverter valve.
air cap: Category : mechanical engineering; A device used in thermal spraying which directs the air pattern for purposes of atomization.
air casing: Category : engineering; A metal casing surrounding a pipe or reservoir and having a space between to prevent heat transmission.
air chamber: Category : mechanical engineering; A pressure vessel, partially filled with air, for converting pulsating flow to steady flow of water in a pipeline, as with a reciprocating pump.
air change: Category : engineering; A measure of the movement of a given volume of air in or out of a building or room in a specified time period, usually expressed in cubic feet per minute.
air check: Category : engineering acoustics; A recording made of a live radio broadcast for filing purposes at the broadcasting facility.
air classifier: Category : mechanical engineering; A device to separate particles by size through the action of a stream of air. Also known as air elutriator.
air cleaner: Category : engineering; Any of various devices designed to remove particles and aerosols of specific sizes from air, examples are screens, settling chambers, filters, wet collectors, and electrostatic precipitators.
air compressor: Category : mechanical engineering; A machine that increases the pressure of air by increasing its density and delivering the fluid against the connected system resistance on the discharge side.
air conditioner: Category : mechanical engineering; A mechanism primarily for comfort cooling that lowers the temperature and reduces the humidity of air in buildings.
air conditioning: Category : mechanical engineering; The maintenance of certain aspects of the environment within a defined space to facilitate the function of that space, aspects controlled include air temperature and motion, radiant heat level, moisture, and concentration of pollutants such as dust, micro
air conveyor: Category : mechanical engineering(see pneumatic conveyor)
air cooling: Category : mechanical engineering; Lowering of air temperature for comfort, process control, or food preservation.
air course: Category : building construction(see airway)
air curtain: Category : mechanical engineering; A stream of high-velocity temperature-controlled air which is directed downward across an opening, it excludes insects, exterior drafts, and so forth, prevents the transfer of heat across it, and permits air-conditioning of a space with an open entrance.
air cushion: Category : mechanical engineering; A mechanical device using trapped air to arrest motion without shock.
air cycle: Category : mechanical engineering; A refrigeration cycle characterized by the working fluid, air, remaining as a gas throughout the cycle rather than being condensed to a liquid, used primarily in airplane air conditioning.
air cylinder: Category : mechanical engineering; A cylinder in which air is compressed by a piston, compressed air is stored, or air drives a piston.
air density: Category : mechanics; The mass per unit volume of air.
air diffuser: Category : building construction; An air distribution outlet, usually located in the ceiling and consisting of deflecting vanes discharging supply air in various directions and planes, and arranged to promote mixing of the supplied air with the air already in the room.
air diving: Category : engineering; A type of diving in which the diver's breathing medium is a normal atmospheric mixture of oxygen and nitrogen, limited to depths of 190 feet (58 meters).
air drain: Category : civil engineering; An empty space left around the external foundation wall of a building to prevent the earth from lying against it and causing dampness.
air drill: Category : mechanical engineering; A drill powered by compressed air.
air drying: Category : engineering; Removing moisture from a material by exposure to air to the extent that no further moisture is released on contact with air, important in lumber manufacture.
air duct: Category : engineering(see airflow duct)
air ejector: Category : mechanical engineering; A device that uses a fluid jet to remove air or other gases, as from a steam condenser.
air eliminator: Category : mechanical engineering; In a piping system, a device used to remove air from water, steam, or refrigerant.
air elutriator: Category : mechanical engineering(see air classifier)
air engine: Category : mechanical engineering; An engine in which compressed air is the actuating fluid.
air entrainment: Category : engineering; The inclusion of minute bubbles of air in cement or concrete through the addition of some material during grinding or mixing to reduce the surface tension of the water, giving improved properties for the end product.
air escape: Category : design engineering; A device that is fitted to a pipe carrying a liquid for releasing excess air, it contains a valve that controls air release while preventing loss of liquid.
air filter: Category : engineering; A device that reduces the concentration of solid particles in an airstream to a level that can be tolerated in a process or space occupancy, a component of most systems in which air is used for industrial processes, ventilation, or comfort air conditionin
air flotation: Category : chemical engineering(see dissolved air flotation)
air grating: Category : building construction; A fixed metal grille on the exterior of a building through which air is brought into or discharged from the building for purposes of ventilation.
air hammer: Category : mechanical engineering(see pneumatic hammer)
air heater: Category : mechanical engineering(see air preheater)
air hoist: Category : mechanical engineering; A lifting tackle or tugger constructed with cylinders and pistons for reciprocating motion and air motors for rotary motion, all powered by compressed air. Also known as pneumatic hoist.
air horn: Category : mechanical engineering; In an automotive engine, the upper portion of the carburetor barrel through which entering air passes in quantities controlled by the choke plate and the throttle plate.
air horsepower: Category : mechanical engineering; The theoretical (minimum) power required to deliver the specified quantity of air under the specified pressure conditions in a fan, blower, compressor, or vacuum pump. Abbreviated air hp.
air hp: Category : mechanical engineering(see air horsepower)
air inlet: Category : mechanical engineering; In an air-conditioning system, a device through which air is exhausted from a room or building.
air knife: Category : engineering; A device that uses a thin, flat jet of air to remove the excess coating from freshly coated paper.
air lift: Category : mechanical engineering(see air-lift pump); Equipment for lifting slurry or dry powder through pipes by means of compressed air.
air meter: Category : engineering; A device that measures the flow of air, or gas, expressed in volumetric or weight units per unit time. Also known as airometer.
air mileage indicator: Category : engineering; An instrument on an airplane which continuously indicates mileage through the air.
air mileage unit: Category : engineering; A device which derives continuously and automatically the air distance flown, and feeds this information into other units, such as an air mileage indicator.
air monitoring: Category : civil engineering; A practice of continuous air sampling by various levels of government or particular industries.
air motor: Category : mechanical engineering; A device in which the pressure of confined air causes the rotation of a rotor or the movement of a piston.
air nozzle: Category : mechanical engineering; In an automotive engine, a device for supplying air to the air-injection reactor.
air outlet: Category : mechanical engineering; In an air-conditioning system, a device at the end of a duct through which air is supplied to a space.
air pocket: Category : engineering; An air-filled space that is normally occupied by a liquid. Also known as air trap.
air preheater: Category : mechanical engineering; A device used in steam boilers to transfer heat from the flue gases to the combustion air before the latter enters the furnace. Also known as air heater, air-heating system.
air propeller: Category : mechanical engineering; A rotating fan for moving air.
air pump: Category : mechanical engineering; A device for removing air from an enclosed space or for adding air to an enclosed space.
air puncher: Category : engineering; A machine consisting essentially of a reciprocating chisel or pick, driven by air.
air purge: Category : mechanical engineering; Removal of particulate matter from air within an enclosed vessel by means of air displacement.
air receiver: Category : mechanical engineering; A vessel designed for compressed-air installations that is used both to store the compressed air and to permit pressure to be equalized in the system.
air register: Category : engineering; A device attached to an air-distributing duct for the purpose of controlling the discharge of air into the space to be heated, cooled, or ventilated.
air regulator: Category : mechanical engineering; A device for regulating airflow, as in the burner of a furnace.
air reheater: Category : mechanical engineering; In a heating system, any device used to add heat to the air circulating in the system.
air release valve: Category : mechanical engineering; A valve, usually manually operated, which is used to release air from a water pipe or fitting.
air resistance: Category : mechanics; Wind drag giving rise to forces and wear on buildings and other structures.
air ring: Category : engineering; In plastics forming, a circular manifold which distributes an even flow of cool air into a hollow tubular form passing through the manifold.
air sampling: Category : engineering; The collection and analysis of samples of air to measure the amounts of various pollutants or other substances in the air, or the air's radioactivity.
air scoop: Category : design engineering; An air-duct cowl projecting from the outer surface of an aircraft or automobile, which is designed to utilize the dynamic pressure of the airstream to maintain a flow of air.
air screw: Category : mechanical engineering; A screw propeller that operates in air.
air separator: Category : mechanical engineering; A device that uses an air current to separate a material from another of greater density or particles from others of greater size.
air shaft: Category : building construction; An open space surrounded by the walls of a building or buildings to provide ventilation for windows. Also known as air well.
air shot: Category : engineering; A shot prepared by loading (charging) so that an air space is left in contact with the explosive for the purpose of lessening its shattering effect.
air space: Category : engineering; An enclosed space containing air in a wall for thermal insulation.
air spring: Category : mechanical engineering; A spring in which the energy storage element is air confined in a container that includes an elastomeric bellows or diaphragm.
air starting valve: Category : mechanical engineering; A device that admits compressed air to an air starter.
air stripping: Category : chemical engineering; The process of bubbling air through water to remove volatile organic substances from the water.
air surveillance: Category : engineering; Systematic observation of the airspace by visual, electronic, or other means, primarily for identifying all aircraft in that airspace, and determining their movements.
air surveillance radar: Category : engineering; Radar of moderate range providing position of aircraft by azimuth and range data without elevation data, used for air-traffic control.
air survey: Category : engineering(see aerial survey)
air sweetening: Category : chemical engineering; A process in which air or oxygen is used to oxidize lead mercaptides to disulfides instead of using elemental sulfur.
air system: Category : mechanical engineering; A mechanical refrigeration system in which air serves as the refrigerant in a cycle comprising compressor, heat exchanger, expander, and refrigerating core.
air thermometer: Category : engineering; A device that measures the temperature of an enclosed space by means of variations in the pressure or volume of air contained in a bulb placed in the space.
air toxics: Category : engineering(see hazardous air pollutants)
air valve: Category : mechanical engineering; A valve that automatically lets air out of or into a liquid-carrying pipe when the internal pressure drops below atmospheric.
air well: Category : building construction(see air shaft)
air-actuated: Category : engineering; Powered by compressed air.
air-arc furnace: Category : engineering; An arc furnace designed to power wind tunnels, the air being superheated to 20,000 K and expanded to emerge at supersonic speeds.
air-assist forming: Category : engineering; A plastics thermoforming method in which air pressure is used to partially preform a sheet before it enters the mold.
air-atomizing oil burner: Category : engineering; An oil burner in which a stream of fuel oil is broken into very fine droplets through the action of compressed air.
airblasting: Category : engineering; A blasting technique in which air at very high pressure is piped to a steel shell in a shot hole and discharged. Also known as air breaking.
airborne collision warning system: Category : engineering; A system such as a radar set or radio receiver carried by an aircraft to warn of the danger of possible collision.
airborne detector: Category : engineering; A device, transported by an aircraft, whose function is to locate or identify an air or surface object.
airborne electronic survey control: Category : engineering; The airborne portion of very accurate positioning systems used in controlling surveys from aircraft.
airborne intercept radar: Category : engineering; Airborne radar used to track and (
airborne magnetometer: Category : engineering; An airborne instrument used to measure the magnetic field of the earth.
airborne profile recorder: Category : engineering; An electronic instrument that emits a pulsed-type radar signal from an aircraft to measure vertical distances between the aircraft and the earth's surface. Abbreviated APR. Also known as terrain profile recorder (TPR).
airborne radar: Category : engineering; Radar equipment carried by aircraft to assist in navigation by pilotage, to determine drift, and to locate weather disturbances, a very important use is locating other aircraft either for avoidance or attack.
airborne waste: Category : engineering; Vapors, gases, or particulates introduced into the atmosphere by evaporation, chemical, or combustion processes, a frequent cause of smog and an irritant to eyes and breathing passages.
air-bound: Category : engineering; Of a pipe or apparatus, containing a pocket of air that prevents or reduces the desired liquid flow.
air-breathing: Category : mechanical engineering; Of an engine or aerodynamic vehicle, required to take in air for the purpose of combustion.
Airco-Hoover sweetening: Category : chemical engineering; Removal of mercaptans from gasoline by caustic and water washes, then heating the dried gasoline and passing it with some oxygen through a reactor containing a slurry of diatomaceous earth impregnated with copper chloride, the oxygen regenerates the catal
air-compressor unloader: Category : mechanical engineering; A device for control of air volume flowing through an air compressor.
air-compressor valve: Category : mechanical engineering; A device for controlling the flow into or out of the cylinder of a compressor.
air-cooled engine: Category : mechanical engineering; An engine cooled directly by a stream of air without the interposition of a liquid medium.
air-cooled heat exchanger: Category : mechanical engineering; A finned-tube (extended-surface) heat exchanger with hot fluids inside the tubes, and cooling air that is fan-blown (forced draft) or fan-pulled (induced draft) across the tube bank.
aircraft detection: Category : engineering; The sensing and discovery of the presence of aircraft, major techniques include radar, acoustical, and optical methods.
aircraft impactor: Category : engineering; An instrument carried by an aircraft for the purpose of obtaining samples of airborne particles.
air-cure: Category : chemical engineering; To vulcanize at ordinary room temperatures, or without the aid of heat.
air-cushion vehicle: Category : mechanical engineering; A transportation device supported by low-pressure, low-velocity air capable of traveling equally well over water, ice, marsh, or relatively level land. Also known as ground-effect machine (GEM), hovercraft.
air-cut: Category : engineering; Referring to the inadvertent mechanical incorporation of air into a liquid system.
air-distributing acoustical ceiling: Category : building construction; A suspended acoustical ceiling in which the board or tile is provided with small, evenly distributed mechanical perforations, designed to provide a desired flow of air from a pressurized plenum above.
airdraulic: Category : mechanical engineering; Combining pneumatic and hydraulic action for operation.
air-exhaust ventilator: Category : mechanical engineering; Any air-exhaust unit used to carry away dirt particles, odors, or fumes.
airfield: Category : civil engineering; The area of an airport for the takeoff and landing of airplanes.
airflow duct: Category : engineering; A pipe, tube, or channel through which air moves into or out of an enclosed space. Also known as air duct.
airflow orifice: Category : engineering; An opening through which air moves out of an enclosed space.
airflow pipe: Category : engineering; A tube through which air is conveyed from one location to another.
air-fuel mixture: Category : mechanical engineering; In a carbureted gasoline engine, the charge of air and fuel that is mixed in the appropriate ratio in the carburetor and subsequently fed into the combustion chamber.
air-handling system: Category : mechanical engineering; An air-conditioning system in which an air-handling unit provides part of the treatment of the air.
air-handling unit: Category : mechanical engineering; A packaged assembly of air-conditioning components (coils, filters, fan humidifier, and so forth) which provides for the treatment of air before it is distributed.
air-heating system: Category : mechanical engineering(see air preheater)
air-injection reactor: Category : mechanical engineering; A unit installed in an automotive engine which mixes fresh air with hot exhaust gases in the exhaust manifold to react with any gasoline that has escaped unburned from the cylinders. Abbreviated AIR.
air-injection system: Category : mechanical engineering; A device that uses compressed air to inject the fuel into the cylinder of an internal combustion engine. Also known as thermactor.
air-inlet valve: Category : mechanical engineering; In a heating/air-conditioning system of a motor vehicle, a valve in the plenum blower assembly that permits selection of either inside or outside air.
air-knife coating: Category : engineering; An even film of coating left on paper after treatment with an air knife.
air-lance: Category : engineering; To direct a pressurized-air stream to remove unwanted accumulations, as in boiler-wall cleaning.
airless spraying: Category : engineering; The spraying of paint by means of high fluid pressure and special equipment. Also known as hydraulic spraying.
air-lift hammer: Category : mechanical engineering; A gravity drop hammer used in closed die forging in which the ram is raised to its starting point by means of an air cylinder.
air-lift pump: Category : mechanical engineering; A device composed of two pipes, one inside the other, used to extract water from a well, the lower end of the pipes is submerged, and air is delivered through the inner pipe to form a mixture of air and water which rises in the outer pipe above the water
air-line lubricator: Category : mechanical engineering(see line oiler)
air-lock strip: Category : building construction; The weather stripping which is fastened to the edges of each wing of a revolving door.
air-mixing plenum: Category : mechanical engineering; In an air-conditioning system, a chamber in which the recirculating air is mixed with air from outdoors.
airometer: Category : engineering(see air meter); An apparatus for both holding air and measuring the quantity of air admitted into it.
air-permeability test: Category : engineering; A test for the measurement of the fineness of powdered materials, such as portland cement.
airplane flare: Category : engineering; A flare, often magnesium, that is dropped from an airplane to illuminate a ground area, a small parachute decreases the rate of descent.
air-pollution control: Category : engineering; A practical means of treating polluting sources to maintain a desired degree of air cleanliness.
airport: Category : civil engineering; A terminal facility used for aircraft takeoff and landing and including facilities for handling passengers and cargo and for servicing aircraft. Also known as aerodrome.
airport engineering: Category : civil engineering; The planning, design, construction, and operation and maintenance of facilities providing for the landing and takeoff, loading and unloading, servicing, maintenance, and storage of aircraft.
airproof: Category : engineering(see airtight)
air-raid shelter: Category : civil engineering; A chamber, often underground, provided with living facilities and food, for sheltering people against air attacks.
air-seasoned: Category : engineering; Treated by exposure to air to give a desired quality.
Airslide conveyor: Category : mechanical engineering; An air-activated gravity-type conveyor, of the Fuller Company, using low-pressure air to aerate or fluidize pulverized material to a degree which will permit it to flow on a slight incline by the force of gravity.
airspeed head: Category : engineering; Any instrument or device, usually a pitot tube, mounted on an aircraft for receiving the static and dynamic pressures of the air used by the airspeed indicator.
airspeed indicator: Category : engineering; A device that computes and displays the speed of an aircraft relative to the air mass in which the aircraft is flying.
air-standard cycle: Category : thermodynamics; A thermodynamic cycle in which the working fluid is considered to be a perfect gas with such properties of air as a volume of 12.4 cubic feet per pound at 14.7 pounds per square inch (approximately 0.7756 cubic meter per kilogram at 101.36 kilopascals) an
air-standard engine: Category : mechanical engineering; A heat engine operated in an air-standard cycle.
air-supply mask: Category : engineering(see air-tube breathing apparatus)
air-suspension encapsulation: Category : chemical engineering; A technique for microencapsulation of various types of solid particles, the particles undergo a series of cycles in which they are first suspended by a vertical current of air while they are sprayed with a solution of coating material, and are then moved
air-suspension system: Category : mechanical engineering; Parts of an automotive vehicle that are intermediate between the wheels and the frame, and support the car body and frame by means of a cushion of air to absorb road shock caused by passage of the wheels over irregularities.
airtight: Category : engineering; Not permitting the passage of air. Also known as airproof.
air-to-air resistance: Category : civil engineering; The resistance provided by the wall of a building to the flow of heat.
air-tube breathing apparatus: Category : engineering; A device consisting of a smoke helmet, mask, or mouthpiece supplied with fresh air by means of a flexible tube. Also known as air-supply mask.
air-tube clutch: Category : mechanical engineering; A clutch fitted with a tube whose inflation causes the clutch to engage, and deflation, to disengage.
air-water jet: Category : engineering; A jet of mixed air and water which leaves a nozzle at high velocity, used in cleaning the surfaces of concrete or rock.
air-water storage tank: Category : engineering; A water storage tank in which the air above the water is compressed.
airway: Category : building construction; A passage for ventilation between thermal insulation and roof boards.
Airy points: Category : engineering; The points at which a horizontal rod is optionally supported to avoid its bending.
Airy stress function: Category : mechanics; A biharmonic function of two variables whose second partial derivatives give the stress components of a body subject to a plane strain.
aisleway: Category : civil engineering; A passage or walkway within a factory, storage building, or shop permitting the flow of inside traffic.
Aitken dust counter: Category : engineering; An instrument for determining the dust content of the atmosphere. Also known as Aitken nucleus counter.
Aitken nucleus counter: Category : engineering(see Aitken dust counter)
alarm gage: Category : engineering; A device that actuates a signal either when the steam pressure in a boiler is too high or when the water level in a boiler is too low.
alarm system: Category : engineering; A system which operates a warning device after the occurrence of a dangerous or undesirable condition.
alarm valve: Category : engineering; A device that sounds an alarm when water flows in an automatic sprinkler system.
albedometer: Category : engineering; An instrument used for the measurement of the reflecting power, that is, the albedo, of a surface.
Alberger process: Category : chemical engineering; A method of manufacturing salt by heating brine at high pressure and passing it to a graveler which removes calcium sulfate, the salt crystallizes as the pressure is reduced and thus is separated from the brine.
alcohol thermometer: Category : engineering; A liquid-in-glass thermometer that uses ethyl alcohol as its working substance.
alcoholimeter: Category : engineering(see alcoholometer)
alcoholmeter: Category : engineering(see alcoholometer)
alcoholometer: Category : engineering; A device, such as a form of hydrometer, that measures the quantity of an alcohol contained in a liquid. Also known as alcoholimeter, alcoholmeter.
aligning drift: Category : mechanical engineering; A rod or bar that is used for aligning parts during assembly.
alignment correction: Category : engineering; A correction applied to the measured length of a line to allow for not holding the tape exactly in a vertical plane of the line.
alignment pin: Category : design engineering; Pin in the center of the base of an octal, loctal, or other tube having a single vertical projecting rib that aids in correctly inserting the tube in its socket.
alignment wire: Category : civil engineering(see ground wire)
alkali ion diode: Category : engineering; In testing for leaks, a device which senses the presence of halogen gases by the use of positive ions of alkali metal on the heated diode surfaces.
alkaline wash: Category : chemical engineering; The removal of impurities from kerosine,used for illuminating purposes, by caustic soda solution.
Alkar process: Category : chemical engineering; Catalytic alkylation of aromatic hydrocarbons with olefins to produce alkylaromatics, for example, production of ethylbenzene from benzene and ethylene.
alkylate bottom: Category : chemical engineering; Residue from fractionation of total alkylate which boils at a higher temperature than aviation gasolines.
alkylation: Category : chemical engineering; A refinery process for chemically combining isoparaffin with olefin hydrocarbons.
allège: Category : building construction; A part of a wall which is thinner than the rest, especially the spandrel under a window.
Allen screw: Category : design engineering; A screw or bolt which has an axial hexagonal socket in its head.
Allen wrench: Category : design engineering; A wrench made from a straight or bent hexagonal rod, used to turn an Allen screw.
alligator shears: Category : engineering; A cutting tool with a fixed lower blade and a movable upper blade (shearing arm) that moves in an arc around a fulcrum pin, used mainly for shearing applications that do not require great accuracy.
alligator wrench: Category : design engineering; A wrench having fixed jaws forming a V, with teeth on one or both jaws.
allocate: Category : industrial engineering; To assign a portion of a resource to an activity.
allowable bearing value: Category : civil engineering; The maximum permissible pressure on foundation soil that provides adequate safety against rupture of the soil mass or movement of the foundation of such magnitude as to impair the structure imposing the pressure. Also known as allowable soil pressure.
allowable load: Category : mechanics; The maximum force that may be safely applied to a solid, or is permitted by applicable regulators.
allowable soil pressure: Category : civil engineering(see allowable bearing value)
allowable stress: Category : mechanics; The maximum force per unit area that may be safely applied to a solid.
allowance: Category : design engineering; An intentional difference in sizes of two mating parts, allowing clearance usually for a film of oil, for running or sliding fits.
allowed hours: Category : industrial engineering(see standard hour)
allowed time: Category : industrial engineering; Amount of time allowed each employee for personal needs during a work cycle.
all-translational system: Category : control systems; A simple robotic system in which there is no rotation of the robot or its components during movements of the robot's body.
all-weather airport: Category : civil engineering; An airport with facilities to permit the landing of qualified aircraft and aircrewmen without regard to operational weather limits.
alpha-ray vacuum gage: Category : engineering; An ionization gage in which the ionization is produced by alpha particles emitted by a radioactive source, instead of by electrons emitted from a hot filament, used chiefly for pressures from 10⁻³ to 10 torrs. Also known as alphatron.
alphatron: Category : engineering(see alpha-ray vacuum gage)
alt: Category : engineering(see altitude)
altazimuth: Category : engineering; An instrument equipped with both horizontal and vertical graduated circles, for the simultaneous observation of horizontal and vertical directions or angles. Also known as astronomical theodolite, universal instrument.
alt-azimuth mounting: Category : engineering(see altitude-azimuth mounting)
alternate energy: Category : engineering; Any source of energy other than fossil fuels that is used for constructive purposes.
alternating current: Category : electricity; Electric current that reverses direction periodically, usually many times per second. Abbreviated ac.
alternating stress: Category : mechanics; A stress produced in a material by forces which are such that each force alternately acts in opposite directions.
alternating-current welder: Category : engineering; A welding machine utilizing alternating current for welding purposes.
altigraph: Category : engineering; A pressure altimeter that has a recording mechanism to show the changes in altitude.
altimeter: Category : engineering; An instrument which determines the altitude of an object with respect to a fixed level, such as sea level, there are two common types: the aneroid altimeter and the radio altimeter.
altimeter corrections: Category : engineering; Corrections which must be made to the readings of a pressure altimeter to obtain true altitudes, involve horizontal pressure gradient error and air temperature error.
altimeter setting: Category : engineering; The value of atmospheric pressure to which the scale of an aneroid altimeter is set, after United States practice, the pressure that will indicate airport elevation when the altimeter is 10 feet (3 meters) above the runway (approximately cockpit height).
altimeter-setting indicator: Category : engineering; A precision aneroid barometer calibrated to indicate directly the local altimeter setting.
altimetry: Category : engineering; The measurement of heights in the atmosphere (altitude), generally by an altimeter.
altitude azimuth: Category : engineering; An azimuth determined by solution of the navigational triangle with altitude, declination, and latitude given.
altitude chamber: Category : engineering; A chamber within which the air pressure, temperature, and so on can be adjusted to simulate conditions at different altitudes, used for experimentation and testing.
altitude curve: Category : engineering; The arc of a vertical circle between the horizon and a point on the celestial sphere, measured upward from the horizon.
altitude datum: Category : engineering; The arbitrary level from which heights are reckoned.
altitude difference: Category : engineering; The difference between computed and observed altitudes, or between precomputed and sextant altitudes. Also known as altitude intercept, intercept.
altitude intercept: Category : engineering(see altitude difference)
altitude-azimuth mounting: Category : engineering; A two-axis telescope mounting in which the azimuth of the direction in which the telescope is pointed is determined by rotation about a vertical axis and the corresponding altitude is determined by rotation about a horizontal axis, computer-controlled mot
aluminize: Category : engineering; To apply a film of aluminum to a material, such as glass.
A-mast: Category : engineering; An A-shaped arrangement of upright poles for supporting a mechanism designed to lift heavy loads.
ambient: Category : engineering; Surrounding, especially, of or pertaining to the environment about a flying aircraft or other body but undisturbed or unaffected by it, as in ambient air or ambient temperature.
American basement: Category : building construction; A basement located above ground level and containing the building's main entrance.
American bond: Category : civil engineering; A bond in which every fifth, sixth, or seventh course of a wall consists of headers and the other courses consist of stretchers. Also known as common bond, Scotch bond.
American caisson: Category : civil engineering(see box caisson)
American filter: Category : engineering(see disk filter)
American melting point: Category : chemical engineering; A temperature 3°F (1.7°C) higher than the American Society for Testing and Materials Method D87 paraffin-wax melting point.
American standard beam: Category : civil engineering; A type of I beam made of hot-rolled structural steel.
American standard channel: Category : civil engineering; A C-shaped structural member made of hot-rolled structural steel.
American standard pipe thread: Category : design engineering; Taper, straight, or dryseal pipe thread whose dimensions conform to those of a particular series of specified sizes established as a standard in the United States. Also known as Briggs pipe thread.
American standard screw thread: Category : design engineering; Screw thread whose dimensions conform to those of a particular series of specified sizes established as a standard in the United States, used for bolts, nuts, and machine screws.
American system drill: Category : mechanical engineering(see churn drill)
American Table of Distances: Category : engineering; Published data concerning the safe storage of explosives and ammunition.
ammeter: Category : engineering; An instrument for measuring the magnitude of electric current flow. Also known as electric current meter.
ammonia absorption refrigerator: Category : mechanical engineering; An absorption-cycle refrigerator which uses ammonia as the circulating refrigerant.
ammonia compressor: Category : mechanical engineering; A device that decreases the volume of a quantity of gaseous ammonia by the amplification of pressure, used in refrigeration systems.
ammonia condenser: Category : mechanical engineering; A device in an ammonia refrigerating system that raises the pressure of the ammonia gas in the evaporating coil, conditions the ammonia, and delivers it to the condensing system.
ammonia liquor: Category : chemical engineering; Water solution of ammonia, ammonium compounds, and impurities, obtained from destructive distillation of bituminous coal.
ammonia meter: Category : engineering; A hydrometer designed specifically to determine the density of aqueous ammonia solutions.
ammonia synthesis: Category : chemical engineering; Chemical combination of nitrogen and hydrogen gases at high temperature and pressure in the presence of a catalyst to form ammonia.
ammonia valve: Category : engineering; A valve that is resistant to corrosion by ammonia.
ammonoxidation: Category : chemical engineering(see ammoxidation)
ammoxidation: Category : chemical engineering; A process in which mixtures of propylene, ammonia, and oxygen are converted in the presence of a catalyst, with acrylonitrile as the primary product. Also known as ammonoxidation, oxyamination.
amortize: Category : industrial engineering; To reduce gradually an obligation, such as a mortgage, by periodically paying a part of the principal as well as the interest.
amount limit: Category : industrial engineering; In a test for a fixed quantity of work, the time required to complete the work or the total amount of work that can be completed in an unlimited time.
ampacity: Category : electricity; Current-carrying capacity in amperes, used as a rating for power cables.
amperage: Category : electricity; The amount of electric current in amperes. Abbreviated amp.
ampere: Category : electricity; The unit of electric current in the rationalized meter-kilogram-second system of units, defined in terms of the force of attraction between two parallel current-carrying conductors. Abbreviated a, A, amp.
ampere-hour meter: Category : engineering; A device that measures the total electric charge that passes a given point during a given period of time.
amperometric transducer: Category : engineering; A transducer in which the concentration of a dissolved substance is determined from the electric current produced between two electrodes immersed in the test solution when one of the electrodes is kept at a selected electric potential with respect to the
amphibious: Category : mechanical engineering; Said of vehicles or equipment designed to be operated or used on either land or water.
amplifier: Category : engineering; A device capable of increasing the magnitude or power level of a physical quantity, such as an electric current or a hydraulic mechanical force, that is varying with time, without distorting the wave shape of the quantity.
amplifier-type meter: Category : engineering; An electric meter whose characteristics have been enhanced by the use of preamplification for the signal input eventually used to actuate the meter.
amplify: Category : engineering acoustics; To strengthen a signal by increasing its amplitude or by raising its level.
amplitude-frequency response: Category : engineering(see frequency response)
amplitude-modulated indicator: Category : engineering; A general class of radar indicators, in which the sweep of the electron beam is deflected vertically or horizontally from a base line to indicate the existence of an echo from a target. Also known as deflection-modulated indicator, intensity-modulated ind
amylograph: Category : engineering; An instrument used to measure and record the viscosity of starch and flour pastes and the temperature at which they gelatinize.
analemma: Category : civil engineering; Any raised construction which serves as a support or rest.
analog output: Category : control systems; Transducer output in which the amplitude is continuously proportional to a function of the stimulus.
analog readout: Category : engineering; A scale on a balance that continuously indicates measurement values by the position of an index mark, either a line or a pointer, opposite a graduated scale which is usually marked with numbers.
analytic mechanics: Category : mechanics; The application of differential and integral calculus to classical (nonquantum) mechanics.
analytical aerotriangulation: Category : engineering; Analytical phototriangulation, performed with aerial photographs.
analytical balance: Category : engineering; A balance with a sensitivity of 0.1-0.01 milligram.
analytical centrifugation: Category : engineering; Centrifugation following precipitation to separate solids from solid-liquid suspensions, faster than filtration.
analytical nadir-point triangulation: Category : engineering; Radial triangulation performed by computational routines in which nadir points are utilized as radial centers.
analytical orientation: Category : engineering; The computational steps required to determine tilt, direction of principal line, flight height, angular elements, and linear elements in preparing aerial photographs for rectification.
analytical photogrammetry: Category : engineering; A method of photogrammetry in which solutions are obtained by mathematical methods.
analytical photography: Category : engineering; Photography, either motion picture or still, accomplished to determine (by qualitative, quantitative, or any other means) whether a particular phenomenon does or does not occur.
analytical phototriangulation: Category : engineering; A phototriangulation procedure in which the spatial solution is obtained by computational routines.
analytical radar prediction: Category : engineering; Prediction based on proven formulas, power tables, or graphs, considers surface height, structural and terrain information, and criteria for radar reflectivity together with the aspect angle and range to the target.
analytical radial triangulation: Category : engineering; Radial triangulation performed by computational routines.
analytical three-point resection radial triangulation: Category : engineering; A method of computing the coordinates of the ground principal points of overlapping aerial photographs by resecting on three horizontal control points appearing in the overlap area.
analytical ultracentrifuge: Category : engineering; An ultracentrifuge that uses one of three optical systems (schlieren, Rayleigh, or absorption) for the accurate determination of sedimentation velocity or equilibrium.
anchor and collar: Category : design engineering; A door or gate hinge whose socket is attached to an anchor embedded in the masonry.
anchor bolt: Category : civil engineering; A bolt used with its head embedded in masonry or concrete and its threaded part protruding to hold a structure or machinery in place. Also known as anchor rod.
anchor buoy: Category : engineering; One of a series of buoys marking the limits of an anchorage.
anchor charge: Category : engineering; A procedure that allows several charges to be preloaded in a seismic shot hole, the bottom charges are fired first, and the upper charges are held down by anchors.
anchor log: Category : civil engineering; A log, beam, or concrete block buried in the earth and used to hold a guy rope firmly. Also known as deadman, ground anchor.
anchor nut: Category : design engineering; A nut in the form of a tapped insert forced under steady pressure into a hole in sheet metal.
anchor pile: Category : civil engineering; A pile that is located on the land side of a bulkhead or pier and anchors it through such devices as rods, cables, and chains.
anchor plate: Category : civil engineering; A metal or wooden plate fastened to or embedded in a support, such as a floor, and used to hold a supporting cable firmly.
anchor rod: Category : civil engineering(see anchor bolt)
anchor station: Category : civil engineering(see anchorage)
anchor wall: Category : civil engineering(see deadman)
anchorage deformation: Category : civil engineering; The shortening of tendons due to their modification or slippage when the prestressing force is transferred to the anchorage device. Also known as anchorage slip.
anchorage slip: Category : civil engineering(see anchorage deformation)
anchored bulkhead: Category : civil engineering; A bulkhead secured to anchor piles.
Andrade's creep law: Category : mechanics; A law which states that creep exhibits a transient state in which strain is proportional to the cube root of time and then a steady state in which strain is proportional to time.
Andrews's curves: Category : thermodynamics; A series of isotherms for carbon dioxide, showing the dependence of pressure on volume at various temperatures.
anelasticity: Category : mechanics; Deviation from a proportional relationship between stress and strain.
anemobiagraph: Category : engineering; A recording pressure-tube anemometer in which the wind scale of the float manometer is linear through the use of springs, an example is the Dines anemometer.
anemoclinometer: Category : engineering; A type of instrument which measures the inclination of the wind to the horizontal plane.
anemogram: Category : engineering; A record made by an anemograph.
anemometer: Category : engineering; A device which measures air speed.
anemoscope: Category : engineering; An instrument for indicating the direction of the wind.
anemovane: Category : engineering; A combined contact anemometer and wind vane used in the Canadian Meteorological Service.
aneroid: Category : engineering(see aneroid barometer); Containing no liquid or using no liquid.
aneroid altimeter: Category : engineering; An altimeter containing an aneroid barometer that actuates the indicator.
aneroid barograph: Category : engineering; An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen which graphs a record on a rotating drum. Also known as aneroidograph, barograph, barometrograph.
aneroid barometer: Category : engineering; A barometer which utilizes an aneroid capsule. Also known as aneroid.
aneroid calorimeter: Category : engineering; A calorimeter that uses a metal of high thermal conductivity as a heat reservoir.
aneroid capsule: Category : engineering; A thin, disk-shaped box or capsule, usually metallic, partially evacuated and sealed, held extended by a spring, which expands and contracts with changes in atmospheric or gas pressure. Also known as bellows.
aneroid diaphragm: Category : engineering; A thin plate, usually metal, covering the end of an aneroid capsule and moving axially as the ambient gas pressure increases or decreases.
aneroid flowmeter: Category : engineering; A mechanism to measure fluid flow rate by pressure of the fluid against a bellows counterbalanced by a calibrated spring.
aneroid liquid-level meter: Category : engineering; A mechanism to measure fluid depth by pressure of the fluid against a bellows which in turn acts on a manometer or signal transmitter.
aneroid valve: Category : mechanical engineering; A valve actuated or controlled by an aneroid capsule.
aneroidograph: Category : engineering(see aneroid barograph)
angel echo: Category : engineering; A radar echo from a region where there are no visible targets, may be caused by insects, birds, or refractive index variations in the atmosphere.
angle back-pressure valve: Category : mechanical engineering; A back-pressure valve with its outlet opening at right angles to its inlet opening.
angle bar: Category : building construction; An upright bar at the meeting of two faces of a polygonal window, bay window, or bow window.
angle bead: Category : building construction; A strip, usually of metal or wood, set at the corner of a plaster wall to protect the corner or serve as a guide to float the plaster flush with it.
angle beam: Category : engineering; Ultrasonic waves transmitted for the inspection of a metallic surface at an angle measured from the beam center line to a normal to the test surface.
angle blasting: Category : engineering; Sandblasting, or the like, at an angle of less that 90º.
angle block: Category : engineering; A small block of wood used to fasten adjacent pieces, usually at right angles, or glued into the corner of a wooden frame to stiffen it. Also known as glue block.
angle board: Category : design engineering; A board whose surface is cut at a desired angle, serves as a guide for cutting or planing other boards at the same angle.
angle bond: Category : civil engineering; A tie used to bond masonry work at wall corners.
angle brace: Category : engineering; A brace across the interior angle of two members that meet at an angle. Also known as angle tie.
angle brick: Category : engineering; Any brick having an oblique shape to fit an oblique, salient corner.
angle clip: Category : civil engineering; A short strip of angle iron used to secure structural elements at right angles.
angle closer: Category : engineering; A specially shaped brick used to close the bond at the corner of a wall.
angle collar: Category : design engineering; A cast-iron pipe fitting which has a socket at each end for joining with the spigot ends of two pipes that are not in alignment.
angle divider: Category : design engineering; A square for setting or bisecting angles, one side is an adjustable hinged blade.
angle dozer: Category : mechanical engineering; A power-operated machine fitted with a blade, adjustable in height and angle, for pushing, sidecasting, and spreading loose excavated material as for opencast pits, clearing land, or leveling runways. Also known as angling dozer.
angle equation: Category : engineering; A condition equation which expresses the relationship between the sum of the measured angles of a closed figure and the theoretical value of that sum, the unknowns being the corrections to the observed directions or angles, depending on which are used in
angle fillet: Category : engineering; A wooden strip, triangular in cross section, which is used to cover the internal joint between two surfaces meeting at an angle of less than 180º.
angle fishplates: Category : civil engineering; Plates which join the rails and prevent the rail joint from sagging where heavy cars and locomotives are used. Also known as angle, angle bar.
angle float: Category : engineering; A trowel having two edge surfaces bent at 90?, used to finish corners in freshly poured concrete and in plastering.
angle gauge: Category : civil engineering; A template used to set or check angles in building construction.
angle gear: Category : mechanical engineering(see angular gear)
angle globe valve: Category : engineering; A globe valve having an angular configuration that permits it to be fitted at bends in pipework.
angle hip tile: Category : building construction(see arris hip tile)
angle joint: Category : engineering; A joint between two pieces of lumber which results in a change in direction.
angle lacing: Category : civil engineering; A system of lacing in which angle irons are used in place of bars.
angle method of adjustment: Category : engineering; A method of adjustment of observations which determines corrections to observed angles.
angle of action: Category : mechanical engineering; The angle of revolution of either of two wheels in gear during which any particular tooth remains in contact.
angle of advance: Category : mechanical engineering(see angular advance)
angle of bite: Category : mechanical engineering(see angle of nip)
angle of depression: Category : engineering; The angle in a vertical plane between the horizontal and a descending line. Also known as depression angle, descending vertical angle, minus angle.
angle of deviation: Category : engineering(see deviation)
angle of dip: Category : engineering(see dip)
angle of elevation: Category : engineering; The angle in a vertical plane between the local horizontal and an ascending line, as from an observer to an object, used in astronomy, surveying, and so on. Also known as ascending vertical angle, elevation angle.
angle of external friction: Category : engineering; The angle between the abscissa and the tangent of the curve representing the relationship of shearing resistance to normal stress acting between soil and the surface of another material. Also known as angle of wall friction.
angle of fall: Category : mechanics; The vertical angle at the level point, between the line of fall and the base of the trajectory.
angle of friction: Category : engineering(see angle of repose)
angle of impact: Category : mechanics; The acute angle between the tangent to the trajectory at the point of impact of a projectile and the plane tangent to the surface of the ground or target at the point of impact.
angle of lead: Category : design engineering(see lead angle)
angle of nip: Category : mechanical engineering; The largest angle that will just grip a lump between the jaws, rolls, or mantle and ring of a crusher. Also known as angle of bite, nip.
angle of obliquity: Category : design engineering(see angle of pressure)
angle of orientation: Category : mechanics; Of a projectile in flight, the angle between the plane determined by the axis of the projectile and the tangent to the trajectory (direction of motion), and the vertical plane including the tangent to the trajectory.
angle of pressure: Category : design engineering; The angle between the profile of a gear tooth and a radial line at its pitch point. Also known as angle of obliquity.
angle of recess: Category : mechanical engineering; The angle that is turned through by either of two wheels in gear, from the coincidence of the pitch points of a pair of teeth until the last point of contact of the teeth.
angle of rest: Category : engineering; The maximum slope at which a heap of any loose or fragmented solid material will stand without sliding, or will come to rest when poured or dumped in a pile or on a slope. Also known as angle of repose.
angle of thread: Category : design engineering; The angle occurring between the sides of a screw thread, measured in an axial plane.
angle of torsion: Category : mechanics; The angle through which a part of an object such as a shaft or wire is rotated from its normal position when a torque is applied. Also known as angle of twist.
angle of twist: Category : mechanics(see angle of torsion)
angle of wall friction: Category : engineering(see angle of external friction)
angle of wrap: Category : design engineering; On a band brake mechanism, the distance, expressed in degrees, that the brake band wraps around the brake flange.
angle paddle: Category : engineering; A hand tool used to finish a plastered surface.
angle plate: Category : design engineering; An L-shaped plate or a plate having an angular section.
angle post: Category : building construction; A railing support used at a landing or other break in the stairs.
angle press: Category : mechanical engineering; A hydraulic plastics-molding press with both horizontal and vertical rams, used to produce complex moldings with deep undercuts.
angle rafter: Category : building construction; A rafter, such as a hip rafter, at the angle of the roof.
angle section: Category : civil engineering; A structural steel member having an L-shaped cross section.
angle stile: Category : building construction; A narrow strip of wood used to conceal the joint between a wall and a vertical wood surface which makes an angle with the wall, as at the edge of a corner cabinet.
angle structure: Category : civil engineering; A method of building a tower for mechanical strength in which braces are placed at angles with respect to the vertical support rods.
angle strut: Category : civil engineering; An angle-shaped structural member which is designed to carry a compression load.
angle valve: Category : design engineering; A manually operated valve with its outlet opening oriented at right angles to its inlet opening, used for regulating the flow of a fluid in a pipe.
angle variable: Category : mechanics; The dynamical variable w conjugate to the action variable J, defined only for periodic motion.
angle-control section: Category : civil engineering(see crossover)
angle-stem thermometer: Category : engineering; A device used to measure temperatures in oil-custody tanks, the angle of the calibrated stem may be 90? or greater to the sensitive portion of the thermometer, as needed to fit the tank shell contour.
angling dozer: Category : mechanical engineering(see angle dozer)
angstrom: Category : mechanics; A unit of length, 10^-10 meter, used primarily to express wavelengths of optical spectra. Abbreviated A, ?. Also known as tenthmeter.
angular acceleration: Category : mechanics; The time rate of change of angular velocity.
angular accelerometer: Category : engineering; An accelerometer that measures the rate of change of angular velocity between two objects under observation.
angular advance: Category : mechanical engineering; The amount by which the angle between the crank of a steam engine and the virtual crank radius of the eccentric exceeds a right angle. Also known as angle of advance, angular lead.
angular bitstalk: Category : mechanical engineering(see angular bitstock)
angular bitstock: Category : mechanical engineering; A bitstock whose handles are positioned to permit its use in corners and other cramped areas. Also known as angular bitstalk.
angular clearance: Category : design engineering; The relieved space located below the straight of a die, to permit passage of blanks or slugs.
angular cutter: Category : mechanical engineering; A tool-steel cutter used for finishing surfaces at angles greater or less than 90? with its axis of rotation.
angular error of closure: Category : engineering(see error of closure)
angular gear: Category : mechanical engineering; A gear that transmits motion between two rotating shafts that are not parallel. Also known as angle gear.
angular impulse: Category : mechanics; The integral of the torque applied to a body over time.
angular lead: Category : mechanical engineering(see angular advance)
angular length: Category : mechanics; A length expressed in the unit of the length per radian or degree of a specified wave.
angular milling: Category : mechanical engineering; Milling surfaces that are flat and at an angle to the axis of the spindle of the milling machine.
angular pitch: Category : design engineering; The angle determined by the length along the pitch circle of a gear between successive teeth.
angular rate: Category : mechanics(see angular speed)
angular shear: Category : mechanical engineering; A shear effected by two cutting edges inclined to each other to reduce the force needed for shearing.
angular speed: Category : mechanics; Change of direction per unit time, as of a target on a radar screen, without regard to the direction of the rotation axis, in other words, the magnitude of the angular velocity vector. Also known as angular rate.
angular travel error: Category : mechanics; The error which is introduced into a predicted angle obtained by multiplying an instantaneous angular velocity by a time of flight.
angular velocity: Category : mechanics; The time rate of change of angular displacement.
angular-contact bearing: Category : mechanical engineering; A rolling-contact antifriction bearing designed to carry heavy thrust loads and also radial loads.
angulator: Category : engineering; An instrument for converting angles measured on an oblique plane to their corresponding projections on a horizontal plane, the rectoblique plotter and the photoangulator are types.
aniline point: Category : chemical engineering; The minimum temperature for a complete mixing of aniline and materials such as gasoline, used in some specifications to indicate the aromatic content of oils and to calculate approximate heat of combustion.
animal balance: Category : engineering; A balance designed to weigh living animals, with a readout or display relatively unaffected by the pulse or movements of the animal.
animal power: Category : mechanical engineering; The time rate at which muscular work is done by a work animal, such as a horse, bullock, or elephant.
anisotropic membrane: Category : chemical engineering; An ultrafiltration membrane which has a thin skin at the separating surface and is supported by a spongy sublayer of membrane material.
anker: Category : mechanics; A unit of capacity equal to 10 U.S. gallons (37.854 liters), used to measure liquids, especially honey, oil, vinegar, spirits, and wine.
anneal: Category : engineering; To treat a metal, alloy, or glass with heat and then cool to remove internal stresses and to make the material less brittle. Also known as temper.
annealing furnace: Category : engineering; A furnace for annealing metals or glass. Also known as annealing oven.
annealing oven: Category : engineering(see annealing furnace)
annealing point: Category : thermodynamics; The temperature at which the viscosity of a glass is 10^13.0 poises. Also known as annealing temperature, 13.0 temperature.
annealing temperature: Category : thermodynamics(see annealing point)
annual cost comparison: Category : industrial engineering; A method of selecting from among several alternative projects or courses of action on the basis of their annual costs, including depreciation.
annular auger: Category : design engineering; A ring-shaped boring tool which cuts an annular channel, leaving the core intact.
annular gear: Category : design engineering; A gear having a cylindrical form.
annular nozzle: Category : design engineering; A nozzle with a ring-shaped orifice.
annular section: Category : engineering; The open space between two concentric tubes, pipes, or vessels.
annunciator: Category : engineering; A signaling apparatus which operates electromagnetically and serves to indicate visually, or visually and audibly, whether a current is flowing, has flowed, or has changed direction of flow in one or more circuits.
anomalous expansion: Category : thermodynamics; An increase in the volume of a substance that results from a decrease in its temperature, such as is displayed by water at temperatures between 0 and 4?C (32 and 39?F).
anomaly finder: Category : engineering; A computer-controlled data-plotting system used on ships to measure and record seismic, gravity, magnetic, and other geophysical data and water depth, time, course, and speed.
anonymous dimensionless group 1-4: Category : chemical engineering; Four of the dimensionless groups, used to solve problems in transfer processes, gas absorption in wetted-wall columns, and laminar boundary-layer flow.
antenna tilt error: Category : engineering; Angular difference between the tilt angle of a radar antenna shown on a mechanical indicator, and the electrical center of the radar beam.
antichlor: Category : chemical engineering; A chemical used in the manufacture of paper or textiles to remove excess chlorine or bleaching solution.
anticollision radar: Category : engineering; A radar set designed to give warning of possible collisions during movements of ships or aircraft.
anticreeper: Category : civil engineering; A device attached to a railroad rail to prevent it from moving in the direction of its length.
antidieseling solenoid: Category : mechanical engineering(see idle-stop solenoid)
antifriction bearing: Category : mechanical engineering; Any bearing having the capability of reducing friction effectively.
antifriction material: Category : engineering; A machine element made of Babbitt metal, lignum vitae, rubber, or a combination of a soft, easily deformable metal overlaid on a hard, resistant one.
anti-g suit: Category : engineering(see g suit)
antiknock blending value: Category : engineering; The numerical improvement by an antiknock additive to gasoline octane, often a greater amount than the additive's own octane value.
antiknock rating: Category : engineering; Measurement of the ability of an automotive gasoline to resist detonation or pinging in spark-ignited engines.
antilock braking system: Category : mechanical engineering; For vehicles, a sensor-control system found in braking systems which prevents wheel lockup while allowing the brakes to continue slowing the wheel. Abbreviated ABS.
antimagnetic: Category : engineering; Constructed so as to avoid the influence of magnetic fields, usually by the use of nonmagnetic materials and by magnetic shielding.
antinoise microphone: Category : engineering acoustics; Microphone with characteristics which discriminate against acoustic noise.
antiozonant: Category : chemical engineering; A protective agent which can be added to rubber during processing to diminish the deteriorating effects of ozone.
antipercolator: Category : mechanical engineering; In an automotive engine, a valve in the carburetor that is designed to vent vapor when the throttle plate is closed, prevents fuel from dropping into the carburetor due to unvented pressure.
antirad: Category : chemical engineering; An inhibitor incorporated into rubber during manufacturing to reduce the degrading effects of radiation.
antiradar coating: Category : engineering; A surface treatment used to reduce the reflection of electromagnetic waves so as to avoid radar detection.
antirattle spring: Category : mechanical engineering; In an automotive vehicle, a spring installed to hold parts in the clutches and the disk brakes together, prevents rattling.
anti-redeposition agent: Category : chemical engineering; An additive used in a detergent to help prevent soil from resettling on a fabric after it has been removed during washing.
antireflection coating: Category : engineering; The application of a thin film of dielectric material to a surface to reduce its reflection and to increase its transmission of light or other electromagnetic radiation.
antiskid plate: Category : engineering; A sheet of metal roughed on both sides and placed between piled objects, such as boxes in a freight car, to prevent sliding.
antismudge ring: Category : building construction; A frame attached around a ceiling-mounted air diffuser, to minimize the formation of rings of dirt on the ceiling.
antitheft device: Category : mechanical engineering; A piece of equipment installed on an automotive vehicle in order to prevent or slow down theft, designs include mechanical locks on the steering wheel and ignition switch as well as other means of shutting off the ignition system, shutting off fuel flow,
AOQL: Category : industrometer
aperiodic waves: Category : electricity; The transient current wave in a series circuit with resistance R, inductance L, and capacitance C when R²C = 4L.
aperture disk: Category : engineering; A disk with a small round opening used in a densitometer to vary the amount of light or the area to be measured.
apex: Category : engineering; In architecture or construction, the highest point, peak, or tip of any structure.
apical angle: Category : mechanics; The angle between the tangents to the curve outlining the contour of a projectile at its tip.
apophorometer: Category : engineering; An apparatus used to identify minerals by sublimation.
apothecaries' dram: Category : mechanics(see dram)
apothecaries' ounce: Category : mechanics(see ounce)
apothecaries' pound: Category : mechanics(see pound)
apparent expansion: Category : thermodynamics; The expansion of a liquid with temperature, as measured in a graduated container without taking into account the container's expansion.
apparent force: Category : mechanics; A force introduced in a relative coordinate system in order that Newton's laws be satisfied in the system, examples are the Coriolis force and the centrifugal force incorporated in gravity.
apparent gravity: Category : mechanics(see acceleration of gravity)
apparent motion: Category : mechanics(see relative motion)
apparent source: Category : engineering acoustics(see effective center)
apparent weight: Category : mechanics; For a body immersed in a fluid (such as air), the resultant of the gravitational force and the buoyant force of the fluid acting on the body, equal in magnitude to the true weight minus the weight of the displaced fluid.
appliance: Category : engineering; A piece of equipment that draws electric or other energy and produces a desired work-saving or other result, such as an electric heater, a radio, or an electronic range.
appliance panel: Category : engineering; In electric systems, a metal housing containing two or more devices (such as fuses) for protection against excessive current in circuits which supply portable electric appliances.
applied research: Category : engineering; Research directed toward using knowledge gained by basic research to make things or to create situations that will serve a practical or utilitarian purpose.
applied strategic research: Category : engineering; Research done to provide a basic understanding of a current applied project.
applied trim: Category : building construction; Supplementary and separate decorative strips of wood or moldings applied to the face or sides of a frame, such as a doorframe.
approach: Category : mechanical engineering; The difference between the temperature of the water leaving a cooling tower and the wet-bulb temperature of the surrounding air.
approach signal: Category : civil engineering; A railway signal warning an engineer of a signal ahead that displays a restrictive indication.
approach vector: Category : control systems; A vector that describes the orientation of a robot gripper and points in the direction from which the gripper approaches a workpiece.
apron conveyor: Category : mechanical engineering; A conveyor used for carrying granular or lumpy material and consisting of two strands of roller chain separated by overlapping plates, forming the carrying surface, with sides 2-6 inches (5-15 centimeters) high.
apron feeder: Category : mechanical engineering; A limited-length version of apron conveyor used for controlled-rate feeding of pulverized materials to a process or packaging unit. Also known as plate-belt feeder, plate feeder.
apron lining: Category : building construction; The piece of boarding which covers the rough apron piece of a staircase.
apron piece: Category : building construction; A beam that supports a landing or a series of winders in a staircase.
apron rail: Category : building construction; A lock rail having a raised ornamental molding.
apron wall: Category : building construction; In an exterior wall, a panel which extends downward from a windowsill to the top of a window below.
aqualung: Category : engineering; A self-contained underwater breathing apparatus (scuba) of the demand or open-circuit type developed by J.Y. Cousteau.
aqueduct: Category : civil engineering; An artificial tube or channel for conveying water.
arbitration: Category : industrial engineering; A semijudicial means of settling labor-management disputes in which both sides agree to be bound by the decision of one or more neutral persons selected by some method mutually agreed upon.
arbor collar: Category : engineering; A cylindrical spacer that positions and secures a revolving cutter on an arbor.
arbor hole: Category : design engineering; A hole in a revolving cutter or grinding wheel for mounting it on an arbor.
arbor press: Category : mechanical engineering; A machine used for forcing an arbor or a mandrel into drilled or bored parts preparatory to turning or grinding. Also known as mandrel press.
arbor support: Category : engineering; A device to support the outer end or intermediate point of an arbor.
arc force: Category : mechanics; The force of a plasma arc through a nozzle or opening.
arc of action: Category : mechanical engineering(see arc of contact)
arc of approach: Category : design engineering; In toothed gearing, the part of the arc of contact along which the flank of the driving wheel contacts the face of the driven wheel.
arc of recess: Category : design engineering; In toothed gearing, the part of the arc of contact wherein the face of the driving wheel touches the flank of the driven wheel.
arc process: Category : chemical engineering; A former process that used electric arcs for fixation (oxidation) of atmospheric nitrogen to manufacture nitric acid.
arc triangulation: Category : engineering; A system of triangulation in which an arc of a great circle on the surface of the earth is followed in order to tie in two distant points.
arch: Category : civil engineering; A structure curved and so designed that when it is subjected to vertical loads, its two end supports exert reaction forces with inwardly directed horizontal components, common uses for the arch are as a bridge, support for a roadway or railroad track, or
arch band: Category : civil engineering; Any narrow elongated surface forming part of or connected with an arch.
arch beam: Category : civil engineering; A curved beam, used in construction, with a longitudinal section bounded by two arcs having different radii and centers of curvature so that the beam cross section is larger at either end than at the center.
arch brace: Category : building construction; A curved brace, usually used in pairs to support a roof frame and give the effect of an arch.
arch bridge: Category : civil engineering; A bridge having arches as the main supports.
arch center: Category : civil engineering; A temporary structure for support of the parts of a masonry or concrete arch during its construction.
arch corner bead: Category : building construction; A corner bead which is cut on the job, used to form and reinforce the curved portion of arch openings.
arch dam: Category : civil engineering; A dam having a curved face on the downstream side, the curve being roughly a portion of a cylinder whose axis is vertical.
arch girder: Category : civil engineering; A normal H-section steel girder bent to a circular shape.
arch press: Category : mechanical engineering; A punch press having an arch-shaped frame to permit operations on wide work.
arch rib: Category : civil engineering; One of a set of projecting molded members subdividing the undersurface of an arch.
arch ring: Category : civil engineering; A curved member that provides the main support of an arched structure.
arch truss: Category : civil engineering; A truss having the form of an arch or arches.
arched construction: Category : building construction; A method of construction relying on arches and vaults to support walls and floors.
arch-gravity dam: Category : civil engineering; An arch dam stabilized by gravity due to great mass and breadth of the base.
Archimedes' screw: Category : mechanical engineering; A device for raising water by means of a rotating broad-threaded screw or spirally bent tube within an inclined hollow cylinder.
architectural acoustics: Category : civil engineering; The science of planning and building a structure to ensure the most advantageous flow of sound to all listeners.
architectural engineering: Category : civil engineering; The branch of engineering dealing primarily with building materials and components and with the design of structural systems for buildings, in contrast to heavy construction such as bridges.
architectural millwork: Category : civil engineering; Ready-made millwork especially fabricated to meet the specifications for a particular job, as distinguished from standard or stock items or sizes. Also known as custom millwork.
architectural volume: Category : civil engineering; The cubic content of a building calculated by multiplying the floor area by the height.
arcometer: Category : engineering; A device for determining the density of a liquid by measuring the apparent weight loss of a solid of known mass and volume when it is immersed in the liquid.
arcticization: Category : engineering; The preparation of equipment for operation in an environment of extremely low temperatures.
are: Category : mechanics; A unit of area, used mainly in agriculture, equal to 100 square meters.
area coverage: Category : engineering; Complete coverage of an area by aerial photography having parallel overlapping flight lines and stereoscopic overlap between exposures in the line of flight.
area drain: Category : civil engineering; A receptacle designed to collect surface or rain water from an open area.
area landfill: Category : civil engineering; A sanitary landfill operation that takes care of the solid waste of more than one municipality in a region.
area meter: Category : engineering; A mechanism to measure fluid flow rate through a fixed-area conduit by the movement of a weighted piston or float supported by the flowing fluid, includes rotameters and piston-type meters.
area of use: Category : engineering; For a balance depending on gravitational acceleration, an area that includes a sufficient number of locations providing a mean value for the gravitational acceleration of the given balance.
area survey: Category : engineering; A survey of areas large enough to require loops of control.
area triangulation: Category : engineering; A system of triangulation designed to progress in every direction from a control point.
area wall: Category : civil engineering; A retaining wall around an areaway.
areaway: Category : civil engineering; An open space at subsurface level adjacent to a building, providing access to and utilities for a basement.
Argand lamp: Category : engineering; A gas lamp having a tube-shaped wick, allowing a current of air inside as well as outside the flame.
argentometer: Category : engineering; A hydrometer used to find the amount of silver salt in a solution.
Arkansas stone: Category : engineering; A whetstone made of Arkansas stone, for sharpening edged tools.
arm conveyor: Category : mechanical engineering; A conveyor in the form of an endless belt or chain to which are attached projecting arms or shelves which carry the materials.
arm elevator: Category : mechanical engineering; A chain elevator with protruding arms to cradle fixed-shape objects, such as drums or barrels, as they are moved upward.
arm solution: Category : control systems; The computation performed by a robot controller to calculate the joint positions required to achieve desired tool positions.
armor plate: Category : building construction; A metal plate which protects the lower part of a door from kicks and scratches, covering the door to a height usually 39 inches (l meter) or more.
armored faceplate: Category : design engineering; A tamper-proof faceplate or lock front, mortised in the edge of a door to cover the lock mechanism.
armored front: Category : design engineering; A lock front used on mortise locks that consists of two plates, the underplate and the finish plate.
arm-tool aggregate: Category : industrial engineering; A biomechanical unit comprising the arm and the tool that it holds and manipulates.
aromatization: Category : chemical engineering; Conversion of any nonaromatic hydrocarbon structure to aromatic hydrocarbon, particularly petroleum.
arostat process: Category : chemical engineering; A process in which aromatic molecules are saturated by catalytic hydrogenation to produce high-quality jet fuels, low-aromatic-content solvents, and high-purity cyclohexane from benzene.
array radar: Category : engineering; A radar incorporating a multiplicity of phased antenna elements.
array sonar: Category : engineering; A sonar system incorporating a phased array of radiating and receiving transducers.
arrestment device: Category : engineering; A locking mechanism installed on a balance for holding one of several levers in place, serves to protect the balance.
arris fillet: Category : building construction; A triangular wooden piece that raises the slates of a roof against a chimney or wall so that rain runs off.
arris gutter: Category : building construction; A V-shaped wooden gutter fixed to the eaves of a building.
arris hip tile: Category : building construction; A special roof tile having an L-shaped cross section, made to fit over the hip of a roof. Also known as hip tile.
arris rail: Category : civil engineering; A rail of triangular section, usually formed by slitting diagonally a strip of square section.
arris tile: Category : building construction; Any angularly shaped tile.
arrissing tool: Category : engineering; A tool similar to a float, but having a form suitable for rounding an edge of freshly placed concrete.
arrisways: Category : civil engineering; Diagonally, in respect to the manner of laying tiles, slates, bricks, or timber. Also known as arriswise.
arriswise: Category : civil engineering(see arrisways)
arrival rate: Category : industrial engineering; The mean number of new calling units arriving at a service facility per unit time.
articulated drop chute: Category : engineering; A drop chute, for a falling stream of concrete, which consists of a vertical succession of tapered metal cylinders, so designed that the lower end of each cylinder fits into the upper end of the one below.
articulated leader: Category : mechanical engineering; A wheel-mounted transport unit with a pivotal loading element used in earth moving.
articulated structure: Category : civil engineering; A structure in which relative motion is allowed to occur between parts, usually by means of a hinged or sliding joint or joints.
articulated train: Category : engineering; A railroad train whose cars are permanently or semipermanently connected.
articulation: Category : control systems; The manner and actions of joining components of a robot with connecting parts or links that allow motion.
articulation point: Category : chemical engineering(see cut point)
artificial atmosphere: Category : chemical engineering; A mixture of gases used in industrial operations in place of air, classified as an active, or process, atmosphere, or an inactive, or protective, atmosphere.
artificial ear: Category : engineering acoustics; A device designed to duplicate the frequency response, acoustic impedance, threshold sensitivity, and relative perception of loudness, consisting of a special microphone enclosed in a box with properties similar to those of the human ear.
artificial ground: Category : electricity; A common correction for a radio-frequency electrical or electronic circuit that is not directly connected to the earth.
artificial monument: Category : engineering; A relatively permanent object made by humans, such as an abutment or stone marker, used to identify the location of a survey station or corner.
artificial nourishment: Category : civil engineering; The process of replenishing a beach by artificial means, such as the deposition of dredged material.
artificial recharge: Category : civil engineering; The recharge of an aquifier depleted by abnormally large withdrawals, by the use of injection wells and other techniques.
artificial variable: Category : industrial engineering; One type of variable introduced in a linear program model in order to find an initial basic feasible solution, an artificial variable is used for equality constraints and for greater-than or equal inequality constraints.
artificial weathering: Category : engineering; The controlled production of changes in materials under laboratory conditions to simulate actual outdoor exposure.
asbestos-cement cladding: Category : building construction; Asbestos board and component wall systems, directly supported by wall framing, forming a wall or wall facing.
as-built drawing: Category : engineering(see as-fitted drawing)
as-built schedule: Category : industrial engineering; The final schedule for a project, reflecting the actual scope, actual completion dates, actual duration of the specified activities, and start dates.
ascending branch: Category : mechanics; The portion of the trajectory between the origin and the summit on which a projectile climbs and its altitude constantly increases.
ascending vertical angle: Category : engineering(see angle of elevation)
as-fitted drawing: Category : engineering; A drawing as amended after completion of an industrial facility in order to provide an accurate record of the details of the entire installation in their final form. Also known as as-built drawing, as-made drawing.
ash: Category : engineering; An undesirable constituent of diesel fuel whose quantitative measurement indicates degree of fuel cleanliness and freedom from abrasive material.
ash collector: Category : engineering(see dust chamber)
ash conveyor: Category : mechanical engineering; A device that transports refuse from a furnace by fluid or mechanical means.
ash dump: Category : engineering; An opening in the floor of a fireplace or firebox through which ashes are swept to an ash pit below.
ash furnace: Category : engineering; A furnace in which materials are fritted for glassmaking.
ash pan: Category : engineering; A metal receptacle beneath a fireplace or furnace grating for collection and removal of ashes.
ash pit: Category : building construction; The ash-collecting area beneath a fireplace hearth.
ash pit door: Category : engineering; A cast-iron door providing access to an ash pit for ash removal.
ashlar: Category : civil engineering; Masonry with an exposed side of square or rectangular stones.
ashlar line: Category : building construction; The outer line of a wall above any projecting base.
as-made drawing: Category : engineering(see as-fitted drawing)
aspect: Category : civil engineering; Of railway signals, what the engineer sees when viewing the blades or lights in their relative positions or colors.
aspect angle: Category : engineering; The angle formed between the longitudinal axis of a projectile in flight and the axis of a radar beam.
asphalt cutter: Category : mechanical engineering; A powered machine having a rotating abrasive blade, used to saw through bituminous surfacing material.
asphalt heater: Category : engineering; A piece of equipment for raising the temperature of bitumen used in paving.
asphalt leveling course: Category : civil engineering; A layer of an asphalt-aggregate mixture of variable thickness, used to eliminate irregularities in contour of an existing surface, prior to the placement of a superimposed layer.
asphalt overlay: Category : civil engineering; One or more layers of asphalt construction on an existing pavement.
asphalt pavement: Category : civil engineering; A pavement consisting of a surface layer of mineral aggregate, coated and cemented together with asphalt cement on supporting layers.
asphalt soil stabilization: Category : civil engineering; The treatment of naturally occurring nonplastic or moderately plastic soil with liquid asphalt at normal temperatures to improve the load-bearing qualities of the soil.
aspirating burner: Category : engineering; A burner in which combustion air at high velocity is drawn over an orifice, creating a negative static pressure and thereby sucking fuel into the stream of air, the mixture of air and fuel is conducted into a combustion chamber, where the fuel is burned i
aspiration meteorograph: Category : engineering; An instrument for the continuous recording of two or more meteorological parameters, with the ventilation being provided by a suction fan.
aspiration psychrometer: Category : engineering; A psychrometer in which the ventilation is provided by a suction fan.
aspiration thermograph: Category : engineering; A thermograph in which ventilation is provided by a suction fan.
aspirator: Category : engineering; Any instrument or apparatus that utilizes a vacuum to draw up gases or granular materials.
assay balance: Category : engineering; A sensitive balance used in the assaying of gold, silver, and other precious metals.
assembling bolt: Category : civil engineering; A threaded bolt for holding together temporarily the several parts of a structure during riveting.
assembly: Category : mechanical engineering; A unit containing the component parts of a mechanism, machine, or similar device.
assembly line: Category : industrial engineering; A mass-production arrangement whereby the work in process is progressively transferred from one operation to the next until the product is assembled.
assembly machine: Category : mechanical engineering; A machine in a manufacturing facility that produces a configuration of some practical value from discrete components.
assembly method: Category : industrial engineering; The technique used to assemble a manufactured product, such as hand assembly, progressive line assembly, and automatic assembly.
assembly-line balancing: Category : industrial engineering; Assigning numbers of operators or machines to each operation of an assembly line so as to meet the required production rate with a minimum of idle time.
assets: Category : industrial engineering; All the resources, rights, and property owned by a person or a company, the book value of these items as shown on the balance sheet.
assignable cause: Category : industrial engineering; Any identifiable factor which causes variation in a process outside the predicted limits, thereby altering quality.
Assmann psychrometer: Category : engineering; A special form of the aspiration psychrometer in which the thermometric elements are well shielded from radiation.
assumed plane coordinates: Category : engineering; A local plane-coordinate system set up at the convenience of the surveyor.
astatic galvanometer: Category : engineering; A sensitive galvanometer designed to be independent of the earth's magnetic field.
astatic governor: Category : mechanical engineering(see isochronous governor)
astatic gravimeter: Category : engineering; A sensitive gravimeter designed to measure small changes in gravity.
astatic magnetometer: Category : engineering; A magnetometer for determining the gradient of a magnetic field by measuring the difference in reading from two magnetometers placed at different positions.
astatic wattmeter: Category : engineering; An electrodynamic wattmeter designed to be insensitive to uniform external magnetic fields.
astatized gravimeter: Category : engineering; A gravimeter, sometimes referred to as unstable, where the force of gravity is maintained in an unstable equilibrium with the restoring force.
astern: Category : engineering; To the rear of an aircraft, vehicle, or vessel, behind, from the back.
astragal front: Category : design engineering; A lock front which is shaped to fit the edge of a door with an astragal molding.
astral lamp: Category : engineering; An Argand lamp designed so that its light is not prevented from reaching a table beneath it by the flattened annular reservoir holding the oil.
astroballistics: Category : mechanics; The study of phenomena arising out of the motion of a solid through a gas at speeds high enough to cause ablation, for example, the interaction of a meteoroid with the atmosphere.
astrolabe: Category : engineering; An instrument designed to observe the positions and measure the altitudes of celestial bodies.
astronomical instruments: Category : engineering; Specific kinds of telescopes and ancillary equipment used by astronomers to study the positions, motions, and composition of stars and members of the solar system.
astronomical theodolite: Category : engineering(see altazimuth)
astronomical traverse: Category : engineering; A survey traverse in which the geographic positions of the stations are obtained from astronomical observations, and lengths and azimuths of lines are obtained by computation.
asymmetric rotor: Category : mechanical engineering; A rotating element for which the axis (center of rotation) is not centered in the element.
asymmetric top: Category : mechanics; A system in which all three principal moments of inertia are different.
asynchronous control: Category : control systems; A method of control in which the time allotted for performing an operation depends on the time actually required for the operation, rather than on a predetermined fraction of a fixed machine cycle.
asynchronous device: Category : control systems; A device in which the speed of operation is not related to any frequency in the system to which it is connected.
asynchronous timing: Category : industrial engineering; A simulation method for queues in which the system model is updated at each arrival or departure, resulting in the master clock being increased by a variable amount.
at: Category : mechanics(see technical atmosphere)
ata: Category : mechanics; A unit of absolute pressure in the metric technical system equal to 1 technical atmosphere.
athermalize: Category : engineering; To make independent of temperature or of thermal effects.
atm: Category : mechanics(see atmosphere)
atmidometer: Category : engineering(see atmometer)
atmometer: Category : engineering; The general name for an instrument which measures the evaporation rate of water into the atmosphere. Also known as atmidometer, evaporation gage, evaporimeter.
atmosphere: Category : mechanics; A unit of pressure equal to 101.325 kilopascals, which is the air pressure measured at mean sea level. Abbreviated atm. Also known as standard atmosphere.
atmospheric cooler: Category : mechanical engineering; A fluids cooler that utilizes the cooling effect of ambient air surrounding the hot, fluids-filled tubes.
atmospheric distillation: Category : chemical engineering; Distillation operation conducted at atmospheric pressure, in contrast to vacuum distillation or pressure distillation.
atmospheric impurity: Category : engineering; An extraneous substance that is mixed as a contaminant with the air of the atmosphere.
atmospheric steam curing: Category : engineering; The steam curing of concrete or cement products at atmospheric pressure, usually at a maximum ambient temperature between 100 and 200?F (40 and 95?C).
atom probe: Category : engineering; An instrument for identifying a single atom or molecule on a metal surface, it consists of a field ion microscope with a probe hole in its screen opening into a mass spectrometer, atoms that are removed from the specimen by pulsed field evaporation fly th
atomic force microscope: Category : engineering; A device for mapping surface atomic structure by measuring the force acting on the tip of a sharply pointed wire or other object that is moved over the surface.
atomic moisture meter: Category : engineering; An instrument that measures the moisture content of coal instantaneously and continuously by bombarding it with neutrons and measuring the neutrons which bounce back to a detector tube after striking hydrogen atoms of water.
atomic power plant: Category : mechanical engineering(see nuclear power plant)
atomization: Category : mechanical engineering; The mechanical subdivision of a bulk liquid or meltable solid, such as certain metals, to produce drops, which vary in diameter depending on the process from under 10 to over 1000 micrometers.
atomizer: Category : mechanical engineering; A device that produces a mechanical subdivision of a bulk liquid, as by spraying, sprinkling, misting, or nebulizing.
atomizer burner: Category : mechanical engineering; A liquid-fuel burner that atomizes the unignited fuel into a fine spray as it enters the combustion zone.
atomizer mill: Category : mechanical engineering; A solids grinder, the product from which is a fine powder.
atomizing humidifier: Category : mechanical engineering; A humidifier in which tiny particles of water are introduced into a stream of air.
attached thermometer: Category : engineering; A thermometer which is attached to an instrument to determine its operating temperature.
attemperation: Category : engineering; The regulation of the temperature of a substance.
attemperation of steam: Category : mechanical engineering; The controlled cooling, in a steam boiler, of steam at the superheater outlet or between the primary and secondary stages of the superheater to regulate the final steam temperature.
attenuate: Category : engineering acoustics; To weaken a signal by reducing its level.
attic: Category : building construction; The part of a building immediately below the roof and entirely or partly within the roof framing.
attic tank: Category : building construction; An open tank which is installed above the highest plumbing fixture in a building and which supplies water to the fixtures by gravity.
attic ventilator: Category : building construction; A mechanical fan located in the attic space of a residence, usually moves large quantities of air at a relatively low velocity.
atticurge: Category : building construction; Of a doorway, having jambs which are inclined slightly inward, so that the opening is wider at the threshold than at the top.
attraction gripper: Category : control systems; A robot component that uses adhesion, suction, or magnetic forces to grasp a workpiece.
attribute sampling: Category : industrial engineering; A quality-control inspection method in which the sampled articles are classified only as defective or nondefective.
attributes testing: Category : engineering; A reliability test procedure in which the items under test are classified according to qualitative characteristics.
attrition mill: Category : mechanical engineering; A machine in which materials are pulverized between two toothed metal disks rotating in opposite directions.
Atwood machine: Category : mechanical engineering; A device comprising a pulley over which is passed a stretch-free cord with a weight hanging on each end.
audible leak detector: Category : engineering; A device used as an auxiliary to the main leak detector for conversion of the output signal into audible sound.
audio patch bay: Category : engineering acoustics; Specific patch panels provided to terminate all audio circuits and equipment used in a channel and technical control facility, this equipment can also be found in transmitting and receiving stations.
audio spectrometer: Category : engineering acoustics(see acoustic spectrometer)
audio system: Category : engineering acoustics(see sound-reproducing system)
audio taper: Category : engineering acoustics; A special type of potentiometer used in a volume-control apparatus to compensate for the nonlinearity of human hearing and give the impression of a linear increase in audibility as volume is raised. Also known as linear taper.
audio-frequency meter: Category : engineering; One of a number of types of frequency meters usable in the audio range, for example, a resonant-reed frequency meter.
audiometer: Category : engineering; An instrument composed of an oscillator, amplifier, and attenuator and used to measure hearing acuity for pure tones, speech, and bone conduction.
audio-modulated radiosonde: Category : engineering; A radiosonde with a carrier wave modulated by audio-frequency signals whose frequency is controlled by the sensing elements of the instrument.
audiphone: Category : engineering acoustics; A device that enables persons with certain types of deafness to hear, consisting of a plate or diaphragm that is placed against the teeth and transmits sound vibrations to the inner ear.
auger bit: Category : design engineering; a A bit shaped like an auger but without a handle, used for wood boring and for earth drilling.
auger boring: Category : engineering(see auger drilling); The hole drilled by the use of auger equipment.
auger conveyor: Category : mechanical engineering(see screw conveyor)
auger drilling: Category : engineering; A method of drilling in which penetration is accomplished by the cutting or gouging action of chisel-type cutting edges forced into the substance by rotation of the auger bit. Also known as auger boring.
auger packer: Category : mechanical engineering; A feed mechanism that uses a continuous auger or screw inside a cylindrical sleeve to feed hard-to-flow granulated solids into shipping containers, such as bags or drums.
auget: Category : engineering; A priming tube, used in blasting. Also spelled augette.
augette: Category : engineering(see auget)
auralization: Category : engineering acoustics(see virtual acoustics)
autoadaptivity: Category : control systems; The ability of an advanced robot to sense the environment, accept commands, and analyze and execute operations.
autoclave: Category : engineering; An airtight vessel for heating and sometimes agitating its contents under high steam pressure, used for industrial processing, sterilizing, and cooking with moist or dry heat at high temperatures.
autoclave curing: Category : engineering; Steam curing of concrete products, sand-lime brick, asbestos cement products, hydrous calcium silicate insulation products, or cement in an autoclave at maximum ambient temperatures generally between 340 and 420?F (170 and 215?C).
autoclave molding: Category : engineering; A method of curing reinforced plastics that uses an autoclave with 50-100 pounds per square inch (345-690 kilopascals) steam pressure to set the resin.
autofrettage: Category : engineering; A process for manufacturing gun barrels, prestressing the metal increases the load at which its permanent deformation occurs.
autogenous grinding: Category : mechanical engineering; The secondary grinding of material by tumbling the material in a revolving cylinder, without balls or bars taking part in the operation.
autogenous healing: Category : engineering; A natural process of closing and filling cracks in concrete or mortar while it is kept damp.
autogenous mill: Category : mechanical engineering(see autogenous tumbling mill)
autogenous tumbling mill: Category : mechanical engineering; A type of ball-mill grinder utilizing as the grinding medium the coarse feed (incoming) material. Also known as autogenous mill.
autoignition: Category : mechanical engineering; Spontaneous ignition of some or all of the fuel-air mixture in the combustion chamber of an internal combustion engine. Also known as spontaneous combustion.
automanual system: Category : civil engineering; A railroad signal system in which signals are set manually but are activated automatically to return to the danger position by a passing train.
automated guided vehicle: Category : industrial engineering; In a flexible manufacturing system, a driverless computer-controlled vehicle equipped with guidance and collision-avoidance systems and used to transport workpieces and tools between work stations. Abbreviated AGV.
automated guided vehicle system: Category : control systems; A computer-controlled system that uses pallets and other interface equipment to transport workpieces to numerically controlled machine tools and other equipment in a flexible manufacturing system, moving in a predetermined pattern to ensure automatic, acc
automatic: Category : engineering; Having a self-acting mechanism that performs a required act at a predetermined time or in response to certain conditions.
automatic balance: Category : engineering; A balance capable of performing weighing procedures without the intervention of an operator.
automatic batcher: Category : mechanical engineering; A batcher for concrete which is actuated by a single starter switch, opens automatically at the start of the weighing operations of each material, and closes automatically when the designated weight of each material has been reached.
automatic calibration: Category : engineering; A process in which an electronic device automatically performs the recalibration of a measuring range of a weighing instrument, for example an electronic balance.
automatic check-out system: Category : control systems; A system utilizing test equipment capable of automatically and simultaneously providing actions and information which will ultimately result in the efficient operation of tested equipment while keeping time to a minimum.
automatic choke: Category : mechanical engineering; A system for enriching the air-fuel mixture in a cold automotive engine when the accelerator is first depressed, the choke plate opens automatically when the engine achieves normal operating temperature.
automatic control: Category : control systems; Control in which regulating and switching operations are performed automatically in response to predetermined conditions. Also known as automatic regulation.
automatic control balance: Category : engineering; An automatic balance fitted with an accessory which determines whether a package has been filled within preselected limits. Also known as checkweigher.
automatic control system: Category : control systems; A control system having one or more automatic controllers connected in closed loops with one or more processes. Also known as regulating system.
automatic controller: Category : control systems; An instrument that continuously measures the value of a variable quantity or condition and then automatically acts on the controlled equipment to correct any deviation from a desired preset value. Also known as automatic regulator, controller.
automatic coupling: Category : mechanical engineering; A device which couples rail cars when they are bumped together.
automatic data processing: Category : engineering; The machine performance, with little or no human assistance, of any of a variety of tasks involving informational data, examples include automatic and responsive reading, computation, writing, speaking, directing artillery, and the running of an entire fa
automatic dialog replacement studio: Category : engineering acoustics(see ADR studio)
automatic door bottom: Category : engineering; A movable plunger, in the form of a horizontal bar at the bottom of a door, which drops automatically when the door is closed, sealing the threshold and reducing noise transmission. Also known as automatic threshold closer.
automatic drill: Category : design engineering; A straight brace for bits whose shank comprises a coarse-pitch screw sliding in a threaded tube with a handle at the end, the device is operated by pushing the handle.
automatic fire pump: Category : mechanical engineering; A pump which provides the required water pressure in a fire standpipe or sprinkler system, when the water pressure in the system drops below a preselected value, a sensor causes the pump to start.
automatic flushing system: Category : civil engineering; A water tank system which provides automatically for the periodic flushing of urinals or other plumbing fixtures, or of pipes having too small a slope to drain effectively.
automatic ignition: Category : engineering; A device that lights the fuel in a gas burner when the gas-control valve is turned on.
automatic indexing: Category : control systems; The procedure for determining the orientation and position of a workpiece with respect to an automatically controlled machine, such as a robot manipulator, that is to perform an operation on it.
automatic microfiller: Category : engineering; A device used to place microfilm in jackets at relatively high speeds.
automatic mold: Category : engineering; A mold used in injection or compression molding of plastic objects so that repeated molding cycles are possible, including ejection, without manual assistance.
automatic press: Category : mechanical engineering; A press in which mechanical feeding of the work is synchronized with the press action.
automatic pumping station: Category : chemical engineering; An installation on a pipeline that automatically provides the proper pressure when a fluid is being transported.
automatic ranging: Category : engineering(see autoranging)
automatic record changer: Category : engineering acoustics; An electric phonograph that automatically plays a number of records one after another.
automatic regulation: Category : control systems(see automatic control)
automatic regulator: Category : control systems(see automatic controller)
automatic sampler: Category : mechanical engineering; A mechanical device to sample process streams (gas, liquid, or solid) either continuously or at preset time intervals.
automatic screw machine: Category : mechanical engineering; A machine designed to automatically produce finished parts from bar stock at high production rates, the term is not an exact, specific machine-tool classification.
automatic shut-off: Category : engineering acoustics; A switch in some tape recorders which automatically stops the machine when the tape ends or breaks.
automatic slips: Category : engineering; A pneumatic or hydraulic device for setting and removing slips automatically. Also known as power slips.
automatic stoker: Category : mechanical engineering; A device that supplies fuel to a boiler furnace by mechanical means. Also known as mechanical stoker.
automatic test equipment: Category : engineering; Test equipment that makes two or more tests in sequence without manual intervention, it usually stops when the first out-of-tolerance value is detected.
automatic threshold closer: Category : engineering(see automatic door bottom)
automatic time switch: Category : engineering; Combination of a switch with an electric or spring-wound clock, arranged to turn an apparatus on and off at predetermined times.
automatic track shift: Category : engineering acoustics; A system used with multiple-track magnetic tape recorders to index the tape head, after one track is played, to the correct position for the start of the next track.
automatic tuning system: Category : control systems; An electrical, mechanical, or electromechanical system that tunes a radio receiver or transmitter automatically to a predetermined frequency when a button or lever is pressed, a knob turned, or a telephone-type dial operated.
automatic volume compressor: Category : engineering acoustics(see volume compressor)
automatic volume expander: Category : engineering acoustics(see volume expander)
automatic wet-pipe sprinkler system: Category : engineering; A sprinkler system, all of whose parts are filled with water at sufficient pressure to provide an immediate continuous discharge if the system is activated.
automatic zero setting: Category : engineering; A system for automatic correction of zero-point drifts or for compensation of soiling of load receivers on a balance by means of a special accessory component.
automatic-control block diagram: Category : control systems; A diagrammatic representation of the mathematical relationships defining the flow of information and energy through the automatic control system, in which the components of the control system are represented as functional blocks in series and parallel arr
automatic-control error coefficient: Category : control systems; Three numerical quantities that are used as a measure of the steady-state errors of an automatic control system when the system is subjected to constant, ramp, or parabolic inputs.
automatic-control frequency response: Category : control systems; The steady-state output of an automatic control system for sinusoidal inputs of varying frequency.
automatic-control servo valve: Category : control systems; A mechanically or electrically actuated servo valve controlling the direction and volume of fluid flow in a hydraulic automatic control system.
automatic-control stability: Category : control systems; The property of an automatic control system whose performance is such that the amplitude of transient oscillations decreases with time and the system reaches a steady state.
automatic-control transient analysis: Category : control systems; The analysis of the behavior of the output variable of an automatic control system as the system changes from one steady-state condition to another in terms of such quantities as maximum overshoot, rise time, and response time.
automatic-type belt-tensioning device: Category : mechanical engineering; Any device which maintains a predetermined tension in a conveyor belt.
automechanism: Category : control systems; A machine or other device that operates automatically or under control of a servomechanism.
automobile: Category : mechanical engineering; A four-wheeled, trackless, self-propelled vehicle for land transportation of as many as eight people. Also known as car.
automobile chassis: Category : mechanical engineering; The automobile frame, together with the wheels, power train, brakes, engine, and steering system.
automotive air conditioning: Category : mechanical engineering; A system for maintaining comfort of occupants of automobiles, buses, and trucks, limited to air cooling, air heating, ventilation, and occasionally dehumidification.
automotive body: Category : engineering; An enclosure mounted on and attached to the frame of an automotive vehicle, to contain passengers and luggage, or in the case of commercial vehicles the commodities being carried.
automotive brake: Category : mechanical engineering; A friction mechanism that slows or stops the rotation of the wheels of an automotive vehicle, so that tire traction slows or stops the vehicle.
automotive engine: Category : mechanical engineering; The fuel-consuming machine that provides the motive power for automobiles, airplanes, tractors, buses, and motorcycles and is carried in the vehicle.
automotive engineering: Category : mechanical engineering; The branch of mechanical engineering concerned primarily with the special problems of land transportation by a four-wheeled, trackless, automotive vehicle.
automotive frame: Category : engineering; The basic structure of all automotive vehicles, except tractors, which is supported by the suspension and upon which or attached to which are the power plant, transmission, clutch, and body or seat for the driver.
automotive ignition system: Category : mechanical engineering; A device in an automotive vehicle which initiates the chemical reaction between fuel and air in the cylinder charge.
automotive steering: Category : mechanical engineering; Mechanical means by which a driver controls the course of a moving automobile, bus, truck, or tractor.
automotive suspension: Category : mechanical engineering; The springs and related parts intermediate between the wheels and frame of an automotive vehicle that support the frame on the wheels and absorb road shock caused by passage of the wheels over irregularities.
automotive transmission: Category : mechanical engineering; A device for providing different gear or drive ratios between the engine and drive wheels of an automotive vehicle, a principal function being to enable the vehicle to accelerate from rest through a wide speed range while the engine operates within its mo
automotive vehicle: Category : mechanical engineering; A self-propelled vehicle or machine for land transportation of people or commodities or for moving materials, such as a passenger car, bus, truck, motorcycle, tractor, airplane, motorboat, or earthmover.
autonomous robot: Category : engineering; A robot that not only can maintain its own stability as it moves, but also can plan its movements.
autonomous vehicle: Category : engineering; A vehicle that is able to plan its path and to execute its plan without human intervention.
autopatrol: Category : mechanical engineering; A self-powered blade grader. Also known as motor grader.
autoradar plot: Category : engineering(see chart comparison unit)
autoradiography: Category : engineering; A technique for detecting radioactivity in a specimen by producing an image on a photographic film or plate. Also known as radioautography.
autorail: Category : mechanical engineering; A self-propelled vehicle having both flange wheels and pneumatic tires to permit operation on both rails and roadways.
autoranging: Category : engineering; Automatic switching of a multirange meter from its lowest to the next higher range, with the switching process repeated until a range is reached for which the full-scale value is not exceeded. Also known as automatic ranging.
autoreducing tachymeter: Category : engineering; A class of tachymeter by which horizontal and height distances are read simultaneously.
autosled: Category : mechanical engineering; A propeller-driven machine equipped with runners and wheels and adaptable to use on snow, ice, or bare roads.
autostability: Category : control systems; The ability of a device (such as a servomechanism) to hold a steady position, either by virtue of its shape and proportions, or by control by a servomechanism.
auxanometer: Category : engineering; An instrument used to detect and measure plant growth rate.
auxiliary dead latch: Category : design engineering; A supplementary latch in a lock which automatically deadlocks the main latch bolt when the door is closed. Also known as auxiliary latch bolt, deadlocking latch bolt, trigger bolt.
auxiliary latch bolt: Category : design engineering(see auxiliary dead latch)
auxiliary power plant: Category : mechanical engineering; Ancillary equipment, such as pumps, fans, and soot blowers, used with the main boiler, turbine, engine, waterwheel, or generator of a power-generating station.
auxiliary rafter: Category : building construction; A member strengthening the principal rafter in a truss.
auxiliary reinforcement: Category : civil engineering; In a prestressed structural member, any reinforcement in addition to that whose function is prestressing.
auxiliary rim lock: Category : design engineering; A secondary or extra lock that is surface-mounted on a door to provide additional security.
auxiliary rope-fastening device: Category : mechanical engineering; A device attached to an elevator car, to a counterweight, or to the overhead dead-end rope-hitch support, that automatically supports the car or counterweight in case the fastening for the wire rope (cable) fails.
auxiliary thermometer: Category : engineering; A mercury-in-glass thermometer attached to the stem of a reversing thermometer and read at the same time as the reversing thermometer so that the correction to the reading of the latter, resulting from change in temperature since reversal, can be computed
auxograph: Category : engineering; An automatic device that records changes in the volume of a body.
auxometer: Category : engineering; An instrument that measures the magnification of a lens system.
availability: Category : systems engineering; The probability that a system is operating satisfactorily at any point in time, excluding times when the system is under repair.
availability ratio: Category : industrial engineering; The ratio of the amount of time a system is actually available for use to the amount of time it is supposed to be available.
available draft: Category : mechanical engineering; The usable differential pressure in the combustion air in a furnace, used to sustain combustion of fuel or to transport products of combustion.
available energy: Category : mechanical engineering; Energy which can in principle be converted to mechanical work.
available heat: Category : mechanical engineering; The heat per unit mass of a working substance that could be transformed into work in an engine under ideal conditions for a given amount of heat per unit mass furnished to the working substance.
available motions inventory: Category : industrial engineering; A list of all motions available to a human for performing a specific task.
avalanche protector: Category : mechanical engineering; Guard plates installed on an excavator to prevent loose material from sliding into the wheels or tracks.
average acoustic output: Category : engineering acoustics; Vibratory energy output of a transducer measured by a radiation pressure balance, expressed in terms of watts per unit area of the transducer face.
average outgoing quality limit: Category : industrial engineering; The average quality of all lots that pass quality inspection, expressed in terms of percent defective. Abbreviated AOQL.
average sample number: Category : industrial engineering; An anticipated number of pieces that must be inspected to determine the acceptability of a particular lot.
averaging: Category : control systems; The reduction of noise received by a robot sensor by screening it over a period of time.
averaging device: Category : engineering; A device for obtaining the arithmetic mean of a number of readings, as on a bubble sextant.
averaging pitot tube: Category : engineering; A flowmeter that consists of a rod extending across a pipe with several interconnected upstream holes, which simulate an array of pitot tubes across the pipe, and a downstream hole for the static pressure reference.
aviation method: Category : engineering; Determination of knock-limiting power, under lean-mixture conditions, of fuels used in spark-ignition aircraft engines.
avionics: Category : engineering; The design and production of airborne electrical and electronic devices, term is derived from aviation electronics.
avogram: Category : mechanics; A unit of mass, equal to 1 gram divided by the Avogadro number.
avoidable delay: Category : industrial engineering; An interruption under the control of the operator during the normal operating time.
avoirdupois pound: Category : mechanics(see pound)
avoirdupois weight: Category : mechanics; The system of units which has been commonly used in English-speaking countries for measurement of the mass of any substance except precious stones, precious metals, and drugs, it is based on the pound (approximately 453.6 grams) and includes the short ton
awl: Category : design engineering; A point tool with a short wooden handle used to mark surfaces and to make small holes, as in leather or wood.
awning window: Category : building construction; A window consisting of a series of vertically arranged, top-hinged rectangular sections, designed to admit air while excluding rain.
ax: Category : design engineering; An implement consisting of a heavy metal wedge-shaped head with one or two cutting edges and a relatively long wooden handle, used for chopping wood and felling trees.
axed brick: Category : engineering; A brick, shaped with an ax, that has not been trimmed. Also known as rough-axed brick.
axhammer: Category : design engineering; An ax having one cutting edge and one hammer face.
axial fan: Category : mechanical engineering; A fan whose housing confines the gas flow to the direction along the rotating shaft at both the inlet and outlet.
axial force diagram: Category : civil engineering; In statics, a graphical representation of the axial load acting at each section of a structural member, plotted to scale and with proper sign as an ordinate at each point of the member and along a reference line representing the length of the member.
axial hydraulic thrust: Category : mechanical engineering; In single-stage and multistage pumps, the summation of unbalanced impeller forces acting in the axial direction.
axial lead: Category : electricity; A wire lead extending from the end along the axis of a resistor, capacitor, or other component.
axial load: Category : mechanics; A force with its resultant passing through the centroid of a particular section and being perpendicular to the plane of the section.
axial modulus: Category : mechanics; The ratio of a simple tension stress applied to a material to the resulting strain parallel to the tension when the sides of the sample are restricted so that there is no lateral deformation. Also known as modulus of simple longitudinal extension.
axial moment of inertia: Category : mechanics; For any object rotating about an axis, the sum of its component masses times the square of the distance to the axis.
axial nozzle: Category : mechanical engineering; An inlet or outlet connection installed in the head of a shell-and-tube exchanger and aligned normal to the plane in which the tube lies.
axial rake: Category : mechanical engineering; The angle between the face of a blade of a milling cutter or reamer and a line parallel to its axis of rotation.
axial relief: Category : mechanical engineering; The relief behind the end cutting edge of a milling cutter.
axial runout: Category : mechanical engineering; The total amount, along the axis of rotation, by which the rotation of a cutting tool deviates from a plane.
axial-flow compressor: Category : mechanical engineering; A fluid compressor that accelerates the fluid in a direction generally parallel to the rotating shaft.
axial-flow pump: Category : mechanical engineering; A pump having an axial-flow or propeller-type impeller, used when maximum capacity and minimum head are desired. Also known as propeller pump.
axial-type mass flowmeter: Category : engineering; An instrument in which fluid in a pipe is made to rotate at a constant speed by a motor-driven impeller, and the torque required by a second, stationary impeller to straighten the flow again is a direct measurement of mass flow.
axis: Category : mechanics; A line about which a body rotates.
axis of freedom: Category : design engineering; An axis in a gyro about which a gimbal provides a degree of freedom.
axis of rotation: Category : mechanics; A straight line passing through the points of a rotating rigid body that remain stationary, while the other points of the body move in circles about the axis.
axis of sighting: Category : engineering; A line taken through the sights of a gun, or through the optical center and centers of curvature of lenses in any telescopic instrument.
axis of symmetry: Category : mechanics; An imaginary line about which a geometrical figure is symmetric. Also known as symmetry axis.
axis of torsion: Category : mechanics; An axis parallel to the generators of a cylinder undergoing torsion, located so that the displacement of any point on the axis lies along the axis. Also known as axis of twist.
axis of twist: Category : mechanics(see axis of torsion)
axle: Category : mechanical engineering; A supporting member that carries a wheel and either rotates with the wheel to transmit mechanical power to or from it, or allows the wheel to rotate freely on it.
axle box: Category : engineering; A bushing through which an axle passes in the hub of a wheel.
axle ratio: Category : mechanical engineering; In an automotive vehicle, the ratio of the speed in revolutions per minute of the drive shaft to that of the drive wheels.
axometer: Category : engineering; An instrument that locates the optical axis of a lens, particularly a lens used in eyeglasses.
azel mounting: Category : engineering(see altazimuth mounting)
azeotropic distillation: Category : chemical engineering; A process by which a liquid mixture is separated into pure components with the help of an additional substance or solvent.
azimuth: Category : engineering; In directional drilling, the direction of the face of the deviation tool with respect to magnetic north.
azimuth alignment: Category : engineering acoustics; The condition whereby the center lines of the playback- and recording-head gaps are exactly perpendicular to the magnetic tape and parallel to each other.
azimuth angle: Category : engineering; An angle in triangulation or in traverse through which the computation of azimuth is carried.
azimuth bar: Category : engineering(see azimuth instrument)
azimuth circle: Category : design engineering; A ring calibrated from 0 to 360? over a compass, compass repeater, radar plan position indicator, direction finder, and so on, which provides means for observing compass bearings and azimuths.
azimuth dial: Category : engineering; Any horizontal circle dial that reads azimuth.
azimuth error: Category : engineering; An error in the indicated azimuth of a target detected by radar.
azimuth indicator: Category : engineering; An approach-radar scope which displays azimuth information.
azimuth instrument: Category : engineering; An instrument for measuring azimuths, particularly a device which fits over a central pivot in the glass cover of a magnetic compass. Also known as azimuth bar, bearing bar.
azimuth line: Category : engineering; A radial line from the principal point, isocenter, or nadir point of a photograph, representing the direction to a similar point of an adjacent photograph in the same flight line, used extensively in radial triangulation.
azimuth scale: Category : engineering; A graduated angle-measuring device on instruments, gun carriages, and so forth that indicates azimuth.
azimuth transfer: Category : engineering; Connecting, with a straight line, the nadir points of two vertical photographs selected from overlapping flights.
azimuth traverse: Category : engineering; A survey traverse in which the direction of the measured course is determined by azimuth and verified by back azimuth.
azimuth-adjustment slide rule: Category : engineering; A circular slide rule by which a known angular correction for fire at one elevation can be changed to the proper correction for any other elevation.
azimuth-stabilized plan position indicator: Category : engineering; A north-upward plan position indicator (PPI), a radarscope, which is stabilized by a gyrocompass so that either true or magnetic north is always at the top of the scope regardless of vehicle orientation.
Azusa: Category : engineering; A continuous-wave, high-accuracy, phase-comparison, single-station tracking system operating at C-band and giving two direction cosines and slant range which can be used to determine space position and velocity of a vehicle (usually a rocket or a missile)

exaVAR

Menu

User login

Dictionary of Engineering

Latest News