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DICTIONARY OF AUTOMOTIVE TERMS (A - E) A: Abbreviation or symbol for absolute temperature , absorption coefficient , acceleration , adenine , ampere , amplitude , angular acceleration , area , attenuation coefficient , fine-structure constant , helium nucleus, Helmhotz free energy , magnetic vector potential , relative atomic mass , a stereoisomer of a sugar, substitution on a carbon atom next to one common to two condensed aromatic nuclei, substitution on the carbon atom next to the hetero-atom in ahetero-cyclic compound, and substitution on the carbon atom of a chain next to the functional group. A-2 tire: A term used for tire sizes 16.00 and larger in nominal cross section. Also called earthmover or off-the-road tire. AA: Abbreviation for "Automobile Association" a term used in Great Britain. aa: A term of Hawaiian origin for lava flows with a rough, jagged surface. AAA: Acronym for "American Automobile Association" or "Alberta Automobile Association." AABM: Acronym for "Association of American Battery Manufacturers, Inc." AAE: Acronym for "Association of Automotive Employers" (Poland).

Dictionary of Automotive Terms

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A: Abbreviation or symbol for absolute temperature, absorption coefficient, acceleration, adenine, ampere, amplitude, angular acceleration, area, attenuation coefficient, fine-structure constant, helium nucleus, Helmhotz free energy, magnetic vector potential, relative atomic mass, a stereoisomer of a sugar, substitution on a carbon atom next to one common to two condensed aromatic nuclei, substitution on the carbon atom next to the hetero-atom in ahetero-cyclic compound, and substitution on the carbon atom of a chain next to the functional group. A-2 tire: A term used for tire sizes 16.00 and larger in nominal cross section. Also called earthmover or off-the-road tire. AA: Abbreviation for "Automobile Association" a term used in Great Britain. aa: A term of Hawaiian origin for lava flows with a rough, jagged surface. AAA: Acronym for "American Automobile Association" or "Alberta Automobile Association." AABM: Acronym for "Association of American Battery Manufacturers, Inc." AAE: Acronym for "Association of Automotive Employers" (Poland).

AAIA: Acronym for "Automotive Aftermarket Industry Association". AALA: Acronym for "American Automobile Labelling Act." aalenian: The oldest stage of the Middle-Jurassic. AAM: Acronym for "Alliance of Automobile Manufacturers". AAP: Acronym for "auxiliary acceleration pump". A arm:See A-arm

A-arm: A suspension linkage formed in the shape of an "A" or "V" found commonly on the front suspension. The sides of the two legs of the A-arm are connected to the chassis by rubber bushings and the peak of the A-arm is attached to the wheel assembly. In this way, the wheel can freely move up and down. Sometimes there is an upper A-arm, a lower A-arm, or both upper and lower A-arms. The British call it a "wishbone."Also see double wishbone

A-arm suspension:See double wishbone


Acronym for "air aspirator system". abacus: [1] The uppermost part of a column capital or pilaster, on which the architrave rests. [2] A bead frame. Used as an arithmetic calculating aid.

abampere: A unit of electric current in the CGS electromagnetic system of units. One abampere equals 10A. abamurus: A supporting wall or buttress, built to add strength to another wall. abandonment: A voluntary surrender of legal rights or title to a mining claim. abatjour: An opening to admit light and generally to deflect it downwards; a skylight. abaxial: Rays of light which do not coincide with the optical axis of a lens system. ABC: [1] Acronym for "aerial bunched conductors" [2] Acronym for "automatic beam control". ABDC: Acronym for after bottom dead center. A term used in timing the relation of the spark and the crankshaft. Abel flashpoint apparatus:

A petroleum-testing apparatus for determining the flash-point. Abelian group: A group in which the group operation is commutative. It is important in the study of rings and vector spaces. aberration: [1] An apparent change of position of a heavenly body, due to the speed of light having a finite ratio to the relative velocity of the source and the observer. [2] In an image-forming system, e.g., an optical or electronic lens, failure to produce a true image, e.g., a point object as a point image. Geometrical aberrations include spherical aberration, coma, astigmatism, curvature of the field, and distortion.See chromatic aberration

abhesive: A substance which prevents two materials sticking together, e.g., Teflon on frying pans. ability:See climbing ability cold cranking ability

ABL: Acronym for "atmospheric boundary layer" panel. ablation: [1] Any one of the processes by which snow and ice are lost from a glacier, mainly by melting and evaporation (sublimation). [2] Removal of surface layers of a meteorite and tektites during flight. ablative polymer: A material which degrades controllably in an aggressive environment, especially on re-entry space-craft. Extreme temperatures are reached on heat shield, so it is protected with ablation shield made of e.g., silicone polymer. The same principle is used in intumescent paints for fire

resistance. Abney law: A rule stating that if a spectral color is desaturated by the addition of white light, and if its wave length is less than 570 nm, its hue then moves towards the red end of the spectrum, while if the wavelength is more than 570 nm its hue moves towards the blue. Abney level: Hand-held instrument in which angles of steep sights are measured while simultaneously viewing a spirit-level bubble. Abney mounting: A form of mounting for a concave diffraction grating, in which the eyepiece (or photographic plate holder) is fixed at the center of curvature of the grating and the slit can move around the circumference of the Rowland circle, to bring different orders of spectrum into view. abnormal glow discharge: A discharge carrying current in excess of that which is required to cover the cathode completely with visible radiation. abnormal reflection: Reflection from the ionosphere of a radio wave whose frequency is greater than the critical frequency. aboard:See lighter aboard ship

aboard ship:See lighter aboard ship

A-bomb:See atomic bomb

A bone:

Nickname for a Ford Model "A". abort: To terminate a vehicle's flight either by failure or deliberate action to prevent dangerous consequences; if manned, a predetermined sequence of events is followed to ensure the safety of the crew. ABPV: Acronym for "air bypass valve". abradant: A substance, usually in powdered form, used for grinding.Also see abrasive

abrade: To scratch or tear away two surfaces in contact by relative motion. Abram's law: A rule that the ratio of water to cement for chemical action to impart strength to concrete is 0.85:1. abrasion: [1] Wearing or rubbing away some surface because of friction. [2] Mechanical wearing away of rocks by rubbing during movement. abrasion hardness: Resistance to abrasive wear, under specified conditions, of metal or mineral. abrasive: A hard grit used for sanding or grinding. It is usually in powdered form, used for the removal of material by scratching and grinding, e.g., silicon carbide powder (carborundum).Also see bonded abrasive

coated abrasive non-woven abrasive

abrasive blast cleaning: A method for preparing steel for painting whereby abrasive particles, e.g., copper slag, are projected under pressure through a nozzle. Very effective in removing rust and mill scale, leaving an anchor pattern (a pattern of minute projections) on the substrate affording good paint adhesion. abrasive cleaner: A cleanser with some hard grit used to remove the grime and oils from a surface. abrasive disc: A circular plate (often made of plastic with hard grit embedded into it) used for grinding or sanding.

abrasive paper: Sandpaper (a paper upon which sand or hard grit has been glued) used for sanding or grinding. abrasive wear: A mechanism of wear due to the presence in one or both surfaces of hard particles (e.g., carbide in steels), or to hard particles trapped between them. A/B roll editing: Video editing using two source players (A and B) enabling dubbing from both. Necessary if scenes are to be superimposed. A/B roll printing: A method of film printing with alternate scenes assembled in two rolls, each having black spacing equivalent in length to the omitted scene; double printing from the two allows the inclusion of fade and dissolve effects and avoids visible splice marks between scenes in 16 mm printing.

ABS: [1] Acronym for "anti-lock brakes. The acronym ABS comes from the German anti blockier system. [2] Acronym for "acylonitrile-butadiene-styrene."Also see copolymer

abscissa: For rectilineal axes of coordinates, the distance of a point from the axis of ordinates measured in a direction parallel to the axis of abscissae, which is usually horizontal. The sign convention is that measurements to the right from the axis of ordinates are positive, measurements to the left negative. absolute: A conic (a quadric in three dimensions) formed by the assemblage of the points at infinity on a line (in general two points). Its form determines the metrical properties of the geometrical system being operated. Thus in Euclidean geometry, the absolute is the degenerate conic comprising the line at infinity taken twice, while in non-Euclidean geometry, the absolute is either a real conic (hyperbolic geometry) or an imaginary conic (elliptic geometry).Also see manifold absolute pressure sensor POA suction throttling valve

absolute address: A computer code designation of a specific memory location as determined by the hardware. absolute age: The geological age of a fossil, mineral, rock or event, generally given in years. absolute ampere: The standard MKS unit of electric current; replaced the international ampere in 1948.

absolute ceiling: The height at which the rate of climb of an aircraft, in standard atmosphere, would be zero; the maximum height attainable under standard conditions. absolute electrometer: A high-grade attracted-disk electrometer in which an absolute measurement of potential can be made by weighing the attraction between two charged disks against gravity. absolute filter: A filter which removes most particulate matter from gases. absolute humidity: The mass (actual amount) of water vapor present in a unit of volume of moist air. absolute instrument: An instrument which measures a quantity directly in absolute units, without the necessity for previous calibration. absolute permeability:See permeability

absolute pressure: Pressure measured from a starting point of zero in perfect vacuum. When measured by the absolute pressure scale, atmospheric pressure is 14.7 psi or 29.92 inches of mercury (in-Hg).Also see manifold absolute pressure sensor

absolute pressure sensor:See manifold absolute pressure sensor barometric absolute pressure sensor

absolute reaction rate: The reaction rate determined from statistical thermodynamics; uses the assumption of the theory of absolute reaction rates that the rate of a

chemical reaction is governed by the rate of crossing an energy barrier or of forming an activated complex. absolute temperature: Temperature measured with respect to absolute zero, i.e., the zero of the kelvin thermodynamic scale of temperature, a scale which cannot take negative values. absolute temperature scale: Also called the absolute scale temperature as measured on a scale in which the hypothetical lowest limit of physical temperature is assigned the value zero. The Kelvin scale is an example of the absolute temperature scale. absolute units: Units derived directly from the fundamental units of a system and not based on arbitrary numerical definitions. The differences between absolute and international units were small; both are now superseded by the definitions of SI units. absolute wavemeter: A wavemeter in which the frequency of the injected radio-frequency signal is by calculation of physical properties (circuit elements or dimensions) of a resonant circuit line or cavity. absolute weight: The weight (or mass) of a body in a vacuum. absolute zero: The point at which there is a total absence of heat, minus 459.67F (-273.15C). absorbance: [1] The logarithm of the ratio of the intensity of light incident on a sample to that transmitted by it. It is usually directly proportional to the concentration of the absorbing substance in a solution.

[2] The capacity of materials such as textile fibers and paper to absorb liquids. absorbed dose: Quantity of energy imparted by ionizing radiation to a unit mass of biological tissue. Unit is the gray. absorbent: Substance with the ability to take up or absorb another substance. absorber: Any material which converts energy of radiation or particles into another form, generally heat. Energy transmitted is not absorbed. Scattered energy is often classed with absorbed energy.Also see direct-acting shock impact absorber absorber lever-type shock double-tube shock absorber absorber monotube shock friction shock absorber absorber self-levelling shock gas shock absorber absorber shock absorber single-tube shock absorber. telescopic shock absorber UV absorber

air shock absorber arc absorber adjustable shock absorbers damper

absorber rod:See control rod

absorber tower:See shock absorber tower

absorbing:See energy absorbing steering column energy absorbing bumper

absorbing bumper:See energy absorbing bumper

absorbing material: Any medium used for absorbing energy from radiation of any type.

absorbing steering:See energy absorbing steering column

absorbing steering column:See energy absorbing steering column

absorptance: A measure of the ability of a body to absorb radiation; the ratio of the radiant flux absorbed by the body to that incident on the body. absorption: The use of reagents to remove unwanted antibodies or antigens from a mixture.Also see acoustic absorption air absorption atmospheric absorption sound absorption

absorption band: A dark gap in the continuous spectrum of white light transmitted by a substance which exhibits selective absorption. absorption capacitor: A capacitor connected across a spark gap to damp the discharge. absorption coefficient: [1] The volume of gas, measured at stp, dissolved by unit volume of a liquid under normal pressure (i.e., one atmosphere). [2] The fraction of the energy which is absorbed. [3] The reduction of amplitude, for a beam of radiation or other wave system incident on a discontinuity in the medium through which it is propagated, or in the path along which it is transmitted. [4] In a medium, the natural logarithm of the ratio of incident and emergent energy or amplitude for a beam of radiation passing through unit thickness of a medium.Also see acoustic absorption coefficient

absorption discontinuity:See absorption edge

absorption dynamometer: A dynamometer which absorbs and dissipates the power which it measures, e.g., the ordinary rope brake and the Froude hydraulic brake. absorption edge: The wavelength at which there is an abrupt discontinuity in the intensity of an absorption spectrum for electromagnetic waves, giving the appearance of a sharp edge in its photograph. The transition is due to one particular energy-dissipating process. absorption factor:See acoustic absorption factor

absorption hygrometer: An instrument by which the quantity of water vapor in air may be measured. absorption inductor:See interphase transformer

absorption lines: Dark lines in a continuous spectrum caused by absorption by a gaseous element. The positions (i.e., wavelengths) of the dark absorption lines are identical to those of the bright lines given by the same element in emission. absorption nebula:See dark nebula

absorption plant: Plant where oils are removed from natural gas by absorption in suitable oil. absorption refrigerator:

[1] A plant in which ammonia is continuously evaporated from an aqueous solution under pressure, condensed, allowed to evaporate, and then reabsorbed. [2] A refrigerator which creates low temperatures by using the cooling effect formed when a refrigerant is absorbed by chemical substance. absorption spectrum: The system of absorption bands or lines seen when a selectively absorbing substance is placed between a source of white light and a spectroscope. absorption wavemeter: A wavemeter which depends on a resonance absorption in a tuned circuit, constructed with very stable inductance and capacitance. absorptive power:See absorptance

absorptivity:See absorptance

ABS override button: A button or switch which disengages the automatic anti-lock braking system so that the driver can operate the brakes himself. ABS relay valve: An electrically controlled valve which modulates the air pressure in the ABS. abundance:See relative abundance frequency

abundance ratio: For a naturally occurring element, the proportion or percentage of one isotope to the total. abundant number:

A natural number for which the sum of the proper factors is greater than the number itself, e.g., 18 is abundant since 1+2+3+6+9>18. Compare deficient number and perfect number. abut: The action of two gear teeth making contact. abutment: [1] A part which stops the motion of another part from proceeding any farther. [2] A cement raised shoulder secured to the side of the road to prevent a vehicle from going over the edge. [3] The contact made between opposing teeth of two gears. abutment load: In stopping or other deep-level excavation, weight transferred to the adjacent solid rock by unsupported roof. abutting edge: The side or edge of a panel which joins another panel. abutting joint: a timber joint whose plane is at right angles to the fibers, the fibers of both joining pieces being in the same straight line. ABV: Acronym for "air bypass valve". abyssal: term describing the ocean floor environment between ca4000 and 6000 m. abyssal deposits: Pelagic marine sediments, accumulating in depths of more than 2000 m including, with increasing depth, calcareous oozes, siliceous oozes and red clay (500 m).

abyssal plain: a flat region of the deep ocean floor with a slope of less than 1:1000. abyssopelagic: relating to the open waters of the abyssal zone. A/C: [1] An abbreviation for air conditioning or air conditioner. [2] An abbreviation for "across corners" which indicates the distance on a nut (for instance) from one corner to the opposite corner rather than the distance from one flat surface (A/F) to the opposite (which would be the size of wrench needed to install or remove the nut). The purpose of the A/C dimension is to know how large a hole might be needed to insert a recessed nut. AC: [1] A vehicle brand of which the 1925-48 models are classic cars. [2] Acronym for "alternating current." [3] Acronym for "air conditioning" or "air conditioner." [4] Symbol for actinium [5] The transformation temperature on heating of the phase changes of iron or steel, subscripts indicating the designated change, e.g., Ac1 is the eutectoid (723C) and Ac3 the ferrite/austenite phase boundary. AC-3: Trade name for the digital audio coding used in 35 mm motion picture film to provide six-channel surround sound. It uses data blocks recorded optically between the perforations, leaving room for a conventional soundtrack. It is also suitable for multi-channel TV audio, as well as video software and home cinema. AC Ace: A vehicle brand of which the 1954-61 Ace models are milestone cars.

AC Aceca: (pronounced ah-SEEK-uh) A vehicle brand of which the 1955-61 Aceca models are milestone cars.

acanthite: An ore of silver, Ag2S, crystallizing in the monoclinic system. ACAP: Acronym for "Associao do comrcio automovvel de Portugal". ac balancer: An arrangement of transformers or reactors used to equalize the voltages between the wires of a multiple-wire system. Also called static balancer. ac bias: A high-frequency signal applied to a magnetic tape recording head along with the signal to be recorded. This stabilizes magnetic saturation and improves frequency response, at the same time reducing noise and distortion. The bias signal frequency has to be many times the highest recording frequency. AC Buckland: A vehicle brand of which the 1949 Buckland Open Tourer is a milestone car.

ac-boundary layer:See stokes layer


Abbreviation for "accessories." ACC: [1] Acronym for "Automatic Cruise Control." [2] A term found on a cruise control switch which indicates the direction the switch needs to be moved to increase the speed (accelerate) of the vehicle. ACCC: Acronym for "air conditioner clutch compressor" signal. accelerate: [1] To increase the speed of a vehicle. Opposite of decelerate. [2] To accelerate an adhesive is to speed up a chemical reaction or a curing process. For example, you can speed up the drying time of an adhesive or sealer by increasing the temperature. Also, by adding a chemical curing agent, or accelerator, to a base compound. accelerated aging test: A stability test for cables using twice normal working voltage. It is claimed this give quick results that correlate with service records. accelerated fatigue test: Test which applies a cyclic loading schedule, which can be of varying frequency and/or amplitude, to a machine or component simulating its loading in service, but at a higher rate, to determine its safe fatigue life before it is reached in service. accelerate-stop distance: The total distance, under specified conditions, in which an aircraft can be brought to rest after accelerating to critical speed for an engine failure at take-off. accelerating chain: The section of an electron beam tube or system, e.g., cathode-ray tube or electron microscope, in which electrons are accelerated by voltages on accelerating electrodes. Also used in particle accelerators.

accelerating electrode: An electrode in a thermionic valve or cathode-ray tube maintained at a high positive potential with respect to the electron source. It accelerates electrons in their flight to the anode but does not collect a high proportion of them. accelerating machine:See accelerator

accelerating potential: The potential applied to an electrode to accelerate electrons from a cathode. accelerating-well ports: These ports prevent momentary leanness during the period that occurs between the opening of the air valve and the actual discharge of fuel from the secondary nozzles. acceleration: The rate of change of velocity or speed. Velocity is steady and is measured in distance per time (e.g., feet per second, miles per hour, kilometers per hour). Acceleration keeps increasing and is measured in velocity per time (e.g., feet (or meters) per second per second or feet (or meters) per second squared). It is a vector quantity and has both magnitude and direction.Also see angular acceleration lateral acceleration sluggish acceleration yaw acceleration

acceleration due to gravity: (g) Acceleration with which a body would fall freely under the action of gravity in a vacuum. This varies according to the distance from the Earth's center, but the internationally adopted value is 9.80665ms-2.Also see Helmert's formula

acceleration enrichment:

The action of increasing the fuel/air mixture during acceleration in order to improve the vehicle's speed and its smooth response. acceleration error: The error in an airborne magnetic compass due to maneuvering; caused by the vertical component of the Earth's magnetic field when the center of gravity of the magnetic element is displaced from normal. acceleration pump:See auxiliary acceleration pump

acceleration slip regulation: (ASR) The Bosch term for traction control. acceleration stress: The influence of acceleration (or deceleration) on certain physiological parameters of the human body. Man can withstand transverse accelerations better than longitudinal ones, which have a profound effect on the cardiovascular system. The degree of tolerance also depends on the magnitude and duration of the acceleration. acceleration tolerance: The maximum acceleration force that a person can withstand before "blacking out" or otherwise losing control. accelerator: [1] In automobiles, this is the "gas pedal" which is attached by linkage to the throttle in the carburetor or to the fuel injection system. It regulates the amount of fuel which is sent to the engine. In motorcycles, the accelerator is located on the right-hand twist grip or an actuating lever. [2] A device, similar to a catapult, but generally

mounted below deck level, for assisting the acceleration of aircraft flying off aircraft carriers. Land versions have been tried experimentally. [3] A chemical which is added to something to make a process happen more quickly. For example, a chemical may be added to paint to cause it to dry faster. The opposite is "retarder." A material added to an adhesive to speed up its cure or to chemically convert the whole mass to a solid. Accelerators differ from catalysts in that they are a part of the chemical reaction and lose their chemical identity as a result. [4] A substance which increases the efficient action of an enzyme [5] Any substance increasing the speed of the vulcanization process of rubber. The principal types are aldehyde derivatives of Schiff's bases: butyraladehyde-butylideneaniline, di-orthotolylguanidine, diphenylguanidine, benzthiazyl disulphide, tetramethylthiuran disulphide and zinc dimethyl-dithiocarbamate. [6] A special circuit board which is placed within a computer to speed up some aspect of its operation. [7] Machine used to accelerate charged particles to very high energies such as betatron, cyclotron, linear

accelerator, synchrocyclotron, and synchrotron. [8] A chemical used to increase the rate of development, e.g., sodium carbonate or borax [9] Any muscle or nerve which increases rate of action.Also see depress the accelerator ease up on the accelerator step on the accelerator take foot off the accelerator

accelerator board: A circuit board plugged into a computer motherboard to increase the operating speed of a computer. accelerator interlock: A connection between the gas pedal and the automatic transmission. accelerator pedal: The accelerator, gas pedal, or throttle pedal. accelerator pump: A small cylinder and piston usually located inside the carburetor that sprays an extra amount of fuel into the engine during acceleration. It improves acceleration by giving more boost and reducing a momentary lag in power. It is actuated by depressing the pedal. accelerometer: [1] A transducer used to provide a signal proportional to the rate of acceleration of a vibrating or other body, usually employing the piezoelectric principle. [2] An instrument which measures the amount of acceleration in a specific direction.Also see impact accelerometer vertical-gust recorder

acceptable quality level: (AQL) A manufactured good that may not be perfect but does reach a level of shape, size, and performance, etc. that will make it work and last as long as the manufacturer expects. acceptance angle: The solid angle within which all incident light reaches the photocathode of a phototube. acceptance test: An examination of a part or its assembly to determine if it meets a prescribed standard. acceptor: [1] The reactant in an induced reaction whose rate of reaction with a third substance is increased by the presence of the inductor. [2] The atom which accepts electrons in a co-ordinate bond. [3] Impurity atoms introduced in small quantities into a crystaline semiconductor and having a lower valency than the semiconductor, from which they attract electrons. In this way holes are produced, which effectively become positive charge carriers; the phenomenon is known as p-type conductivity.Also see donor impurity

acceptor level:See energy levels

access: A way of reaching something that is usually hidden or covered.Also see access panel

Access Cab: A type of pickup truck (by Toyota) which as a second row of seating; but unlike a crew cab (which has four full size doors) it has a "half-door" that can be opened only after the main door is opened. The seating is usually a

little more cramped than in a crew cab. Also called club Cab, extended Cab, king Cab, xtracab, supercab, or cab Plus access charge: A financial charge for access to a computer or telecommunications network. access eye: A screwed plug provided in soil, waste and drain pipes at bends and junctions, to clear a stoppage. access hole: An opening through which you can reach something. It is usually covered with a panel. accessible hermetic: Assembly of motor and compressor inside a single bolted housing unit. accessories: Items and packages of equipment which are beyond the standard equipment supplied in a new vehicle. accessory:See accessories

accessory gearbox: A gearbox, driven remotely from an aero-engine, on which aircraft accessories, e.g., hydraulic pump and electrical generator, are mounted. accessory minerals: Minerals which occur in small, often minute, amounts in igneous rocks; their presence or absence makes no difference to classification and nomenclature. accessory package:

A set of features or appointments which may be ordered at extra cost on a new vehicle. accessory plates: Quartz-wedge, gypsum plate and mica plate. Used with petrological microscope to help determine the optical character of a mineral as an aid in its examination. accessory shoe: A mounting bracket on the body of a camera to which separate units such as a flash or range-finder may be fitted. access panel: The cover which conceals the engine on a mid-engine vehicle. Also called engine cover.Also see hood

access time: The time interval between the instant at which data are called from memory and the instant at which the data can be used. It can vary from microseconds with fast store to minutes with magnetic tape. access to store: Entry or extraction of data from a memory location. The method and speed of access depends on the type of memory.Also see backing store fast store random access memory serial access memory

accident:See car accident

accident damage: The destruction caused to a vehicle's bodywork when it is involved in an accident.

ac circuit: A circuit which passes alternating current as opposed to direct current, e.g., it may have a capacitor in series, which blocks direct current. ac commutator motor: An ac motor which embodies a commutator as an essential part of its construction.Also see ac series motor compensated induction motor repulsion motor Schrage motor

Accord: A model of automobile manufactured by Honda

. Click for books on Honda Accord

accordion: The method of folding a leaflet or insert so that it opens out and closes in a zig-zag fashion. The British term is concertina fold. accretion: [1] The process in which a celestial body, particularly an evolved star in a binary system, is enlarged by the accumulation of extraneous matter falling in under gravity [2] The process of enlargement of a continent by the tectonic coalescences of exotic crustal fragments. accretion disc: The disc of material at the edge of a black hole, which has been attracted from a neighboring star and which emits X-rays as its inner edge disappears into the gravitational field of the hole.

accumulation point: A mathematical term which says that of a set of points, one such that every neighborhood of it includes at least one point of the set. accumulator: [1] A storage battery for an electric car. [2] A pressurized container for an automatic leveling suspension system. [3] A part of the hydraulic system which is charged by the fluid pump, absorbs fluctuating fluid delivery, stores fluid at pressure, and can provide a rapid flow of fluid under pressure. [4] A vessel that stores hydraulic fluid under pressure. [5] A storage tank which receives liquid refrigerant from evaporator and prevents it from flowing into the suction line before vaporizing. [6] A refrigerant storage device used on General Motors and Ford systems that receives vapor and liquid refrigerant from the evaporator. The accumulator, which contains "desiccant," performs a function similar to that of a receiver-drier: it separates liquid from the vapor, retains the liquid and releases the vapor to the compressor. Always located on the low side of the system. [7] A special storage register associated with the arithmetic logic unit, used for holding the results of a computation or data transferAlso see accumulator piston fuel accumulator hydraulic accumulator pressure accumulator

accumulator battery: A storage battery (i.e., the main battery in your vehicle). accumulator box: A vessel usually made of plastic which contains the plates and electrolyte of an accumulator. accumulator drier: A device which is part of the air conditioning system. It is made up of a tank, filter, drying agent, and a vapor return tube. It is usually found on the

evaporator outlet. It stores the excess refrigerant and removes the moisture from the refrigerant (thus the name "drier").Also see receiver drier

accumulator grid: The lead grid which forms one of the plates of a lead-acid accumulator having pasted plates. accumulator piston: A unit found in the automatic transmission to assist the servo to apply the brake band quickly and smoothly. accumulator system: In an automatic transmission, it includes a hydraulic accumulator piston which is controlled by a valve. accumulator traction:See battery traction

accumulator valve: A device which operates the hydraulic accumulator piston in an automatic transmission. accumulator vehicle:See battery traction

AC current sine wave: Wave form of single frequency alternating current; wave whose displacement is sine of angle proportional to time or distance. Ace: An American trucker's colloquial term for someone with a class "A" licence.Also see AC Ace

ACEA: Acronym for "Association des Constructeurs europens dAutomobiles" (i.e., European Automakers Association). Aceca:See AC Aceca

acet-: Prefix from the Latin acetum meaning vinegar. acetate film: Film with its photographic emulsion coated on a base of cellulose triacetate, of low flammability. aceto-: Prefix from the Latin acetum meaning vinegar. acetylene: [1] Ethyne HCCH. A colorless, poisonous gas, owing its disagreeable odor to impurities; soluble in ethanol, in acetone (25 times its volume at standard temperature and pressure) and in water. Boiling point -84C, relative density 0.91. Prepared by the action of water on calcium carbide and catalytically from naphtha. [2] A gas composed of two parts of carbon and two parts of hydrogen. When burned in an atmosphere of oxygen, it produces one of the highest flame temperatures obtainable for welding. [3] Also used for illuminating, acetic acid synthesis and for manufacturing derivativesAlso see oxygen acetylene cutting

acetylene bottle:See acetylene cylinder

acetylene cutting:See oxygen acetylene cutting

acetylene cylinder: A specially built container manufactured according to I.C.C. Standards. Used to store and ship acetylene. Also called acetylene tank or acetylene bottle

acetylene hose: A flexible medium used to carry gases from regulators to the torch. It is made of fabric and rubber. acetylene regulator: An automatic valve used to reduce acetylene cylinder pressures to torch pressures and to keep the pressures constant. acetylene tank: acetylene cylinder. acetyl group: Ethanoyl group CH3CO-. The radical of acetic acid. aceval: Abbreviation for air combat evaluation.

AC generator: [1] An electromagnetic generator for producing alternating emf and delivering ac to an outside circuit. [2] A generator produces direct current (DC) while an alternator produces alternating current (AC). Because alternators were introduced to automobile electrical systems after generators had been in use for some time, some people referred to the new alternator as "AC generator." ache:See head ache rack

ache rack:See head ache rack

achromatic lens: A lens designed to minimize chromatic aberration. The simplest form consists of two component lenses, one convergent, the other divergent, made of glasses having different dispersive powers, the ratio of their focal lengths being equal to the ratio of the dispersive powers. achromatic prism: An optical prism with a minimum of dispersion but a maximum of deviation. achromatic sensation: A visual perception of grey. Represented by the equal energy point on a chromaticity diagram. achromatic stimulus: Stimulus which produces an achromatic sensation. acid:Also see battery acid chromic acid

oxalic acid

acid brittleness: The brittleness developed in steel in pickling bath, through evolution of hydrogen. acid condition in system: Condition in which refrigerant or oil in system is mixed with fluids that are acid in nature. acid cure: In extraction of uranium from its ores, lowering of gangue carbonates by puddling with sulphuric acid before leach treatment. acid deposition: Acid compounds emitted into the atmosphere which then return to the surface either in the form in which they were discharged or as new compounds formed by reaction in the atmosphere. Includes dry deposition, usually of sulphur and nitrogen oxides near the source, and wet deposition which follows when acids are washed from the atmosphere by precipitation (i.e., acid rain and occult deposition. acid drift: The process by which ores, pulps, and products become acidic through pick-up of atmospheric oxygen through standing. acid dyes: Dyes which have their color associated with the negative ion or radical. acid egg: A pump for sulphuric acid, of simple and durable construction, with few moving parts. The acid is run into a pressure vessel, usually egg-shaped, from which it can be forcibly expelled by compressed air. acid fixer: Fixing solution (hypo) with the addition of an acid (sodium bisulphite or potassium metabisulphite) to prevent staining.

acidizing: Improving the flow of oil from a limestone formation by pumping acid into it. acid mine water: Water containing sulphuric acid as a result of the breakdown of the sulphide minerals in rocks. Acid mine water causes corrosion of mining equipment, and may contaminate water supplies into which it drains. acid process: [1] A steel-making process in which the furnace is lined with a siliceous refractory, and for which iron low in phosphorous is required, as this element is not removed. [2] Any pulp digestion process utilizing an acid regent, e.g., a bisulphite liquor with some free sulphur dioxide. acid rain: [1] When the smoke created by factories and vehicle exhausts is taken by the wind and joined with rain clouds, the mixture is often acidic. As a result the rain that falls to the ground (and even on your car) may damage whatever it strikes. [2] A form of wet deposition in which acid molecules or particles in the atmosphere are returned to the surface having been washed out by rain or snow as it falls. The unnatural acidity (pH 3-5.5) is caused mainly by the oxides of sulphur and nitrogen from the burning of coal and oil. acid refractory:See silica

acid resist foils: Blocking foils for use in etching metal. The foil is stamped on to paper and the excess foil blocked on to the metal rule or other object which is then exposed to an acidic etching fluid such as ferric chloride. acid rock:

An igneous rock with more than 63% quartz. acid slag: Furnace slag in which silica and alumina exceed lime and magnesia. acid smut:See acid soot

acid soot: A pollutant, consisting of particles of carbon bound together by water containing sulphuric acid, formed as a by-product of the incomplete combustion of carbon-based fuel. Also called acid smut. acid steel: Steel made by an acid process. acid stop: Weak acid photography processing solution used immediately after the developer to halt its chemical activity and neutralize it before fixing. AC Ignition System:See continuous AC Ignition System

Ackermann:See Ackermann steering

Ackermann steering: [1] A double-pivoting steering system where the outer ends of the steering arms are bent slightly inward so that when the vehicle is making a turn, the inside wheel will turn more sharply than the outer wheel. This is done to compensate for the greater distance the outside wheel must travel. Notice 20 degrees on left wheel and 30 degrees on right wheel [2] Arrangement whereby a line extended from the track-arms, when the wheels are set straight ahead, should meet on the chassis centerline at 2/3 of the wheelbase from the front, allowing the inner stub-axle to move through a greater angle than the outer. Ackermann angle: The toe-out or toe-in of a vehicle with Ackermann steering when the wheels are positioned straight ahead. Ackermann axle: In a vehicle with Ackermann steering (at the front of the vehicle), it is a non-rotating axle that is steerable and has two pivot points (one on each end of the axle) with vertical kingpins. acknowledgement signal: A signal transmitted along a circuit from B to A when triggered by a signal from A to B. A-class insulation: Insulating material which will withstand temperatures up to 105C. ACL BI-MET: Acronym for "air cleaner bi-metal sensor". ACL DV: Acronym for "air cleaner duct and valve vacuum" motor.

ACM: Abbreviation for Association for Computing Machinery, a US professional association. ac magnet: Electromagnet excited by alternating current having normally a laminated magnetic circuit.Also see shaded pole

acme screw-thread: A thread having a profile angle of 29 and a flat crest and root, used for example for lathe lead screw for easy engagement by a split nut. acmite: A variety of aegirine; also used for the NaFe+3Si2 O6 end-member. ac motor: An electric motor which operates from a single or polyphase alternating current supply.Also see capacitor motor induction motor synchronous motor

acnode:See double point

acoustic absorption: Transfer of energy into thermal energy when sound is incident at an interface. acoustic absorption coefficient: The ratio of the acoustic energy absorbed by a surface to that which is incident on the surface. For an open window this can be 1.00, for painted plaster 0.02. The value varies with the frequency of the incident sounds, e.g., for 2 cm glass fiber it is 0.04 at 125 Hz, 0.80 at 4000 Hz. Also called acoustic absorption factor.

acoustic absorption factor: The ratio of the acoustic energy absorbed by a surface to that which is incident on the surface. For an open window this can be 1.00, for painted plaster 0.02. The value varies with the frequency of the incident sounds, e.g., for 2 cm glass fiber it is 0.04 at 125 Hz, 0.80 at 4000 Hz. Also called acoustic absorption coefficient. acoustical inertia: The quantity M, where M is the part of the acoustical reactance which corresponds to the inductance of an electrical reactance: is the pulstance, given by 2f is the frequency in hertz. Also called acoustical mass. acoustical mass: The quantity M, where M is the part of the acoustical reactance which corresponds to the inductance of an electrical reactance: is the pulstance, given by 2f is the frequency in hertz. Also called acoustical inertia. acoustical stiffness: For an enclosure of volume V, the quantity given by S-pc/V, where c is velocity of propagation of sound and p is density. It is assumed that the dimensions of the enclosure are small compared with the sound wavelength and that the walls around the volume do not deflect. acoustic amplifier: An amplifier of mechanical vibrations. acoustic branch: A branch of the dispersion curve (frequency against wavenumber q) for crystal lattice vibrations for which is proportional to q for small q. For a crystal containing n atoms per unit cell, the dispersion curve has 3n branches of which three are acoustic branches. The branches are characterized by different patterns of movement of the atoms.Also see optic branch

acoustic center:

The effective source point of the spherically divergent wave system observed at distinct points in the radiation field of an acoustic transducer. acoustic compliance: The reciprocal of the acoustic stiffness. acoustic construction: Building construction which aims at the control of transmission of sound, or of mechanical vibration giving rise to sound, particularly unwanted noises. The parts of the structure are separated by air-spaces or acoustic absorbing material and can be decoupled by the interposing of springs. acoustic coupler: A device which enables a digital signal to be transmitted over the telephone network using an ordinary telephone handset. acoustic delay line: A device, magnetostrictive or piezoelectric, e.g., a quartz bar or plate of suitable geometry, which reflects an injected sound pulse many times within the body. acoustic distortion: Distortion in sound-reproducing systems. acoustic emission: Non-destructive testing method of investigating deformation and failure processes in materials by the signals generated when the elastic waves released by them are detected at the materials' surfaces. acoustic feedback: Instability or oscillation in a second reproduction system caused by the microphone or pick-up receiving vibrations from the loudspeaker. acoustic filter: Filter which uses tubes and resonating boxes in shunt and series as reactance elements, providing frequency cut-offs in acoustic wave

transmission, as in an electric wave filter. acoustic grating: A diffraction grating for production of directive sound. Spacings are much larger than in optical gratings due to the longer wavelength of sound waves. Both transmission and reflection grating are used. acoustic impedance: the complex ratio of sound pressure on surface to sound flux through surface, having imaginary (reactance) and real (resistance) components, respectively. Unit is the acoustic ohm. acoustic interferometer: Instrument in which measurements are made by study of interference pattern set up by two sound or ultrasonic waves generated at the same source. acoustic lens: A system of slats or disks to spread or converge sound waves. acoustic microscope: Microscope based on acoustic waves (longitudinal compressions and rarefactions of density) at microwave frequencies the interaction of an acoustic wave with a material is sensitive to its elastic properties. Images can be created by modulating a display with the intensity received by a detector/specimen system scanned synchronously (ultrasonic imaging). Coupling between electrical signals and acoustic vibrations exploits the piezoelectric effect. acoustic model: A scale model of a room (e.g., concert hall) or structure which is used to measure qualities important for architectural acoustics and noise control (e.g., sound distribution). The scale is typically between 1:10 and 1:20. In order to adjust the wavelength, the frequency has to be increased by a factor of 10-20. acoustic ohm:

Unit of acoustic resistance, reactance, and impedance, equal to 105Pasm-3. acoustic perspective: The quality of depth and localization inherent in a pair of ears, which is destroyed in a single channel for sound reproduction. It is transferable with two microphones and two telephone ear-receivers with matched channels, and more adequately realized with three microphones and three radiating receivers with three matched channels. acoustic plaster: Rough or flocculent plaster which has good acoustic absorbing properties and which can be used for covering walls. Added to the mix is fine aluminum, which evolves gas on contact with water and so aerates the mass. These tiny holes lower the acoustic impedance and so reduce the reflection of incidence sound waves. acoustic pressure:See sound pressure

acoustic radiator: Device to generate and radiate sound. The more common radiators are (1) vibrating elastic systems (membrane, string, vocal cord) which cause a fluctuating pressure in the surrounding medium; (2) electrically driven membranes and plates (loudspeaker, sonar transducer); (3) vortices in turbulent fluid flow. acoustic ratio: The ratio between the directly radiated sound intensity from a source, at the ear of a listener (or a microphone), and the intensity of the reverberant sound in the enclosure. The ratio depends on the distance from the source, the polar distribution of the radiated sound power, and the period of reverberation of the enclosure. acoustic reactance:See acoustic impedance

acoustic resistance:See acoustic impedance

acoustic resonance: Enhancement of response to an acoustic pressure of a frequency equal or close to the eigenfrequency of the responding system. When a system is at resonance, the imaginary part of its impedance is zero. Prominent in Helmholtz resonators, organ, and other pipes and vibrating strings. acoustics: [1] The science of sound waves including production and propagation properties. [2] The characteristics of a room which determine the quality of sound transmission inside.Also see architectural acoustics atmospheric acoustics

acoustic saturation: The aural effectiveness of a source of sound amid other sounds; it is low for a violin, but high for a triangle. The relative saturation of instruments indicates the number required in an auditorium of given acoustic properties. acoustic scattering: Irregular and multi-directional reflection and diffraction of sound waves produced by multiple reflecting surfaces the dimensions of which are small compared to the wavelength; or by certain discontinuities in the medium through which the wave is propagated. acoustic spectrometer: An instrument designed to analyze a complex sound signal into its wavelength components and measure their frequencies and relative intensities.Also see real-time analyzer

acoustic spectrum: Graph showing frequency distribution of sound energy emitted by source. acoustic streaming:

Generation of constant flows by a strong sound wave. Acoustic streaming is a non-linear effect. It is responsible for the motion of the light particles (lycopodium spores) in a Kundt's tube.Also see quartz wind

acoustic survey: Determination of the porosity of a rock by measuring the time required for a sonic impulse to travel through a given distance. acoustic suspension: Sealed-cabinet system of loudspeakers in which the main restoring force of the diaphragm is provided by the acoustic stiffness of the enclosed air. acoustic telescope: An array of microphones. The signals of the microphones are added with certain phase-delays so as to generate desired directions.Also see directional microphone

acoustic tile: A tile made of soft, sound-absorbing substance. acousto-optic modulator: A telecommunication device in which acoustic waves in an optical medium from a grating used to diffract an optical signal and thus effectively turn it on or off. acquisition fee: A charge for processing a lease and is probably not negotiable. On a shorter term lease, the acquisition fee can have a large impact on the cost of the lease. ACR: Abbreviation for approach control radar. acro-:

Prefix from Greek akros (), topmost, farthest, terminal. Acrobat: Trade name for a computer application which converts text, line drawings, and half-tones into a stream of alphanumeric text while retaining the format of the original. Such a page description file (PDF) is an extension of the Adobe PostScript language and can be read by any type of computer. acronical rising: The rising of a star at nightfall. acronical setting: The setting of a star at nightfall. acronychal: British term for "acronical". across corners: (A/C) The distance on a nut (for instance) from one corner to the opposite corner rather than the distance from one flat surface (A/F) to the opposite (which would be the size of wrench needed to install or remove the nut). The purpose of the A/C dimension is to know how large a hole might be needed to insert a recessed nut. across flats: (A/F) The distance on a nut (for instance) from one flat surface to the opposite flat surface, i.e., this is the size of the wrench needed to install or remove the nut.Also see across corners.

acroterium: A base or mounting on the apex and/or extremities of a pediment, for the support of an ornamental figure or statuary.

ACR tubing: Tubing used in air conditioners and refrigerators. The ends are sealed to keep tubing clean and dry. acrux: A bright white supergiant star in the constellation Crux. A visual binary consisting of two spectroscopic binary components. Distance 80 pc. Also called Alpha Crucis. acrylate: A polymer used to strengthen rubber (e.g., ethyl acrylate). acrylic: A term relating to a type of paint made by polymerizing acrylonitrile. acrylic fibers: Continuous filaments or, more fibers from linear polymers which are synthesized from several monomers containing at least 85% by weight of acrylonitrile. acrylic finish: A final coating of paint which uses acrylic paint, often where the pigment and an acrylic paint are mixed together.Also see two-pack paint.

acrylic paint: A type of paint made by polymerizing acrylonitrile. acrylic resin: A thermoplastic synthetic polymer made by polymerizing an acrylic derivative such as acrylonitrile, acrylic acid, ethyl acrylate, and methacrylate. It is used for adhesives, protective coatings, and paint finishes. ACS:

[1] Abbreviation for active control system [2] Abbreviation for attitude control system [3] Abbreviation for air conditioning system . ac series motor: A series motor which operates from an ac supply with laminated field construction and usually a compensating winding. AC Shelby Cobra: A vehicle brand of which the 1962-67 Shelby Cobra models are milestone cars. ACT: [1] Acronym for "air charge temperature." [2] Acronym for active control technology.Also see active control system

act:See Motor Vehicle Safety Act

acting:See double-acting dual-acting single-acting

actinic radiation: Ultraviolet waves, which have enhanced biological effect by inducing chemical change; basis of the science of photochemistry. actinic rays: Electromagnetic waves of wavelength that can cause a latent image, potentially able to be developed, in a photographic emulsion. They include an extension at each end of the visible spectrum and X-rays. actino-:

Prefix from Greek aktis (). actinolite: A monoclinic calcium magnesium iron member of the amphibole group, green in color and usually showing an elongated or needle-like habit; occurs in metamorphic and altered basic igneous rocks. action: [1] The performance of a scene to be recorded on camera [2] The film record of this performance as picture only, separate from the sound record [3] The time integral of kinetic energy (E) of a conservative dynamic system undergoing a change, given by this formula:Also see capillary action caster action mist action oscillating action parallel action locking pliers reciprocating action

action brakes:See servo action brakes

action locking:See parallel action locking pliers

action locking pliers:See parallel action locking pliers

activate: To change an adhesive film from a dry or inactive state to a useful, sticky state. activated:See cable activated

activated alumina:

Chemical which is a form of aluminum oxide. it is used as a drier or desiccant. activated carbon: [1] A highly porous carbon which is able to absorb gases and fluids. It is usually found in small pellets so that the surface area is greater than a large chunk of it. Also it has a number of pores on each pellet to increase the surface area more. Thus the greater surface area means greater ability to absorb. Used to clean air. Also called activated charcoal. [2] Carbon obtained from vegetable matter by carbonization in the absence of air, preferably in a vacuum. Activated carbon has the property of absorbing large quantities of gasses. Important for gas masks, adsorption of solvent vapors, clarifying of liquids, and in medicine. activated carbon canister: An automotive filter in which activated carbon has been placed so that gas tank fuel vapors, which have accumulated when the vehicle is not running, are trapped in the filter. When the engine is running, hot air is forced into the filter and push out the vapors into the engine. In this way, pollution is reduced and conservation of the fuel is maintained. Also called activated charcoal trap or charcoal canister. activated cathode: Emitter in thermionic devices comprising a filament of basic tungsten metal, alloyed with thorium, which is brought to the surface by process of activation, such as heating without electric field. activated charcoal: Charcoal treated with acid to increase its adsorptive powerAlso see activated carbon charcoal

activated charcoal trap:See activated carbon canister

activated sintering: Sintering of a compact in the presence of a gaseous reactant. Also called reaction sintering.

activating agent:See activator

activation: [1] Alteration of the surface of a metal to a chemically active state. Compare passivation [2] Induction of radioactivity in otherwise non-radioactive atoms, e.g., in a cyclotron or reactor. activation cross-section: The effective cross-sectional area of a target nucleus undergoing bombardment by e.g., neutrons for radioactivation analysis. Measured in barns.Also see cross-section

activator: [1] A substance which is used to speed up the process of curing a tire. [2] Surface-active chemical used in a flotation process to increase the attraction to a specific mineral in an aqueous pulp of collector ions from the ambient liquid and increase in aerophilic quality. Also called activating agent. active array: An antenna array in which the individual elements are separately excited by integrated circuit or transistor amplifiers. active braking time: The length of time (excluding the driver's reaction time) a vehicle takes to come to a complete stop after the brakes are applied. active component: The component of the vector representing an alternating quantity which is in phase with some reference vector; e.g., the active component of the current, commonly called the active current.Also see

active current active voltage active volt-amperes

active control: Modern technique of noise or vibration control using one or more sources that generate signals with the aim of making the resulting total signal smaller. Used for example for the control of low-frequency airborne noise and vibration of machinery.Also see antisound

active control system: (ACS) An advanced automatic flight control system designed to provide several special features, for example activation of flight control surfaces to minimize gust loads and bending stresses in the wing by detection and response to normal accelerations, provision of stability to a naturally unstable aircraft and implementation of pilot maneuver demands. All these characteristics improve aircraft behavior and performance, but the active control system demands extensive integration between aerodynamics, structure, and electronic system design to achieve these advantages with reliability and safety. active current: The component of a vector representing the ac in a circuit which is in phase with the voltage of the circuit. The product of this and the voltage gives power. active device: A component capable of controlling voltages or currents, to produce gain or switching action in a circuit, valves, diodes, and transistors, and integrated circuits are all classed as active devices or components. active electrode: The electrode of an electrical precipitator which is kept at a high potential. Also called discharge electrode.. active filter:

A filter which combines amplification with conventional passive filter components (capacitance, inductance, resistance) to enhance fixed or tunable passband or rejection characteristics. active galaxy: A galaxy which emits unusually large amounts of radiation from a compact central source, such as Seyfert galaxy, N galaxy, quasar, or BL Lac object. active homing: A guidance system where the missile contains the transmitter for illuminating the target and the receiver for the reflected energy. active lattice: The regular pattern of arrangement of fissionable and non-fissionable materials in the core of a lattice reactor. active lines: Lines which are effective in establishing a picture. active material: In a storage battery, peroxide of lead (brown) in positive plates and metallic lead (gray) in negative plates upon which sulphuric acid acts. active materials: [1] General term for essential materials required for the functioning of a device, e.g., iron or copper in a relay or machine, electrode materials in a primary or secondary cell, emitting surface material in a valve, or photocell, phosphorescent and fluorescent material forming a phosphorescent and fluorescent material forming a phosphor in a cathoderay tube, or that on the signal plate of a TV camera. [2] Term applied to all types of radioactive isotopes. active noise control system:See anti-noise system

active power:

The time average over one cycle of the instantaneous input powers at the points of entry of a polyphase circuit.Also see active volt-amperes

active safety: The opposite of passive safety. Passive safety involves seat belts, airbags, bumpers, etc. so that in the event of an accident the passengers are protected. Active safety involves factors which will assist the driver in avoiding an accident. They include brakes, steering, handling response, acceleration, etc. active satellite: A satellite equipped for sending out probing signals and receiving returned information. A passive satellite receives information only on the state of the target. active sun: The Sun during periods of intense sunspot activity. active suspension: While conventional suspension uses springs and shock absorbers to isolate the vehicle from the bouncing movement of the wheels when it contacts rough roads, active suspension uses power actuators which are controlled by a computer. These actuators place the wheels of the vehicle in the best position to accommodate rough roads as well as compensate for different load levels. active transducer: Any transducer in which the applied power controls or modulates locally supplied power, which becomes the transmitted signal, as in a modulator, a radio transmitter or a carbon microphone. active voltage: The component of a vector representing the voltage which is in phase with the current in a circuit.

active volt-amperes: The product of the active voltage and the amperes in a circuit, or of the active current (amperes) and the voltage of the circuit; equal to the power in watts. Also called active power. activities:See Kaizen Activities

activity: [1] The magnitude of the oscillations of a piezoelectric crystal relative to the exciting voltage [2] The rate at which transformations occur in a radionuclide. Unit is the becquerelAlso see catalytic activity low temperature activity specific activity

activity factor:See blade activity factor

ac transformer: an electromagnetic device which alters the voltage and current of an ac supply in inverse ratio to one another. It has no moving parts and is very efficient. ACTS: Acronym for "air charge temperature sensor". actual cash value: (ACV) The amount of money a dealer has invested in the purchase of a used vehicle and any additional costs to repair the unit in order to get it ready for resale. actual throat: A welding term which describes the distance from the face of a weld to the root of the weld.

actuate: The action of bringing a part or assembly into operation. actuating lever: A triggering device used to bring a part or assembly into operation. actuating switch: A triggering device used to bring a part or assembly into operation. actuation:See variable valve actuation

actuator: [1] A Device which controls or operates another device. [2] The portion of a regulating valve which converts mechanical fluid, thermal energy, or electrical energy into mechanical motion to open or close the valve seatsAlso see hydraulic actuators

actuator arm: An arm connecting the diaphragm to the contact breaker platform in an advance mechanism. Also called diaphragm link.. Acura: A vehicle brand from the Honda manufacturers. Click for books on Acura

acutance: Objective formulation of the sharpness of a photographic image, expressed as where . "N" is the number of increments between "A" and "B", DB-DA is the average gradient of density curve, and D/x is the maximum gradient curve.

ACV: [1] Acronym for "actual cash value." [2] Acronym for "air control valve" [3] Acronym for air cushion vehicle (i.e., hovercraft). ad:See classified ad

A-D: Analogue-to-digital, referring to the conversion of signals. adamantine:See lustre

adaptation layer:See ATM adaptation layer

adapter: [1] A device used to connect two different types or sizes of electrical terminals [2] An arrangement for using types of photographic material in a camera different from that for which it was designed; e.g., filmpack in a plate camera, or a smaller plate than normal [3] A device for the interchange of lenses between different types of camera [4] A connector which links two items usually of dissimilar structure or size. (Also spelled "adaptor")Also see bit adapter bit adapter caliper mounting bracket carburetor adapter engine adapter increasing adapter ratchet adapter reducing adapter transmission adapter wheel adapter.

adaptive array: A radar antenna (either a phased array or an active array) whose gain, directivity and side lobes can be adjusted automatically to optimize the radar's performance under specific operating conditions. adaptive control: The ability of a control unit to adapt its closed-loop operation to changing operating conditions -- such as engine wear, fuel quality or altitude -- to maintain proper air-fuel mixture control, ignition timing or idle rpm. Also referred to as self-learning. adaptive differential pulse code modulation: A form of differential pulse code modulation in which the basic step size is varied continually to suit the rate of change of the signal. A further refinement is to transmit only differences from a continually adjusted prediction of the signal. These measures greatly reduce the required bandwidth. adaptive radiation: Evolutionary diversification of species from a common ancestral stock, filling available ecological niches. Also called divergent adaptation. adaptor carburetor: A device attached to a gasoline carburetor which permits an internal combustion engine to run either on gas or liquefied petroleum gas (LP gas). adapter plate: A plate which is placed between two different parts in order to link them. (Also spelled "adaptor plate")Also see transfer plate

Adcock antenna: A directional antenna consisting of pairs of vertical wires, spaced by one half wavelength or less, and fed in phase opposition; a figure-of-eight radiation pattern results, and arrays of Adcock antennas can be used for direction-finding.

ADD: Acronym for "airstream direction detector" which is used for aircraft stall protection. add-drop multiplexer: Equipment used to add data originating from a particular source or group of sources to a synchronous digital hierarchy data stream, or conversely to extract data destined for a particular source or group of sources. addendum: [1] The radial distance between the major and pitch cylinders of an external thread. [2] The radial distance between the minor and pitch cylinders of an internal thread the height from the pitch circle to the tip of the tooth on a gearwheel. addition agent: A substance added to the electrolyte in an electro deposition process in order to improve the character of the deposit formed. The agent does not take part in the main electrochemical reaction. additive: A substance (liquid or powder) which is added to gasoline or oil and is intended to improve the characteristics of the original product.Also see anti-knock additive fuel additive oil additive

additive constant: A survey term used in the computation of distance by tacheometric methods. It is that length (usually constant and small) which must be added to the product of staff intercept and multiplying constant to give the true distance of the object.Also see anallatic lens

additive printer: Photographic or motion picture printer or enlarger in which the intensity and color of the exposing light is controlled by the separate variation of its red, green, and blue components. additive process: Color reproduction in which the picture is presented by the combination (addition) of red, green, and blue light representing these three components in the original subject; it is effectively obsolete for general photography and cinematography but is the basis for color TV display. ADEFA: Acronym for "Asociacion de Fabricas de Automotores" (Argentina). adenine: (A) One of the five bases in nucleic acids. It pairs with thymine in DNA and uracil in RNA. ADF: Abbreviation for automatic direction finding. adhara: Avery bright blue-white giant star in the constellation Canis Major, which is a visual binary. Distance 200 pc. Also called Epsilon Canis Majoris. adhere: To stick or be glued to something. adherend: [1] Each surface that is to adhere to another [2] A material which is bonded by an adhesive. adhesion: [1] The force which causes two surfaces to adhere, the sticking together of surfaces in contact with each other

[2] The bonding of materials with adhesives (glues, cements, binders, etc), in which the intermolecular forces between adhesive and adherend provide the bonds. [3] The intimate sticking together of metallic surfaces under compressive stresses by bonds which form as a function of stress, time, and temperature. The speed of formation is related to dislocation, and may occur virtually instantaneously under high shear stresses.Also see cold welding

[4] The ability of paint, primer, or glue to stick to the surface to which it is applied. [5] The ability of a tire to grip the surface of the road. [6] Mutual forces between two magnetic bodies linked by magnetic flux, or between two charged non-conducting bodies which keeps them in contact [7] Intermolecular forces which hold matter together, particularly closely contiguous surfaces of neighboring media, e.g., liquid in contact with a solid.Also see intercoat adhesion failure limits of adhesion

adhesion failure:See intercoat adhesion failure

adhesive: [1] A substance (like glue) that is used to join two substances. An adhesive must bond both mating surfaces through specific adhesion (molecular attraction), through mechanical anchoring (by flowing into holes in porous surfaces), or through fusion (partial solution of both surfaces in the adhesive or its solvent vehicle). Various descriptive adjectives are used with the term adhesive to indicate types, such as: a. physical form liquid adhesive, film adhesive, etc. b. composition resin adhesive, rubber adhesive, silicone based, mastic, etc. c. end use metal-to-metal adhesive, plastic adhesive, rubber adhesive d. application sprayable adhesive, hot melt adhesive, etc.

[2] Agent for joining materials by adhesion, usually polymeric material. May be based on thermoplastic resin (e.g., polystyrene cement) or thermoset (e.g., epoxy resin). Viscosity is important for gap filling (high, as in epoxies) or surface penetration (low, as in cyano-acrylates). Also called binder, cement, or glueAlso see automotive adhesive air drying adhesives impact adhesive separate-application adhesive

adhesive binding: Unsewn binding in which the back of the sections are trimmed and roughened before adhesive is applied to bind the leaves and the cover. adhesive film: A thin layer of dried adhesive. Also describes a class of adhesives provided in dry film form with or without reinforcing fabric and which are cured by means of heat and pressure. adhesive tape: A tape with a sticky substance on one side. It usually comes in a roll of various widths. Sometimes used to insulate electrical wires (e.g., electrical tape) or to wrap a larger object (e.g., duct tape). Often the non-sticky side is shiny (but not always). adhesive wear: Mechanism of wear due to the welding together and subsequent shearing off of the contact areas between two surfaces sliding over one another. adhesive weight: Lead wheel weights which have a sticky backing. It comes in strips and is applied to a wheel rim. Also called tape weight.. adiabatic: A property of being able to maintain heat evenly. It does not gain any heat or lose it.Also see

thermal efficiency

adiabatic change: A change in the volume and pressure of the contents of an enclosure without exchange of heat between the enclosure and its surroundings. adiabatic compression: Compressing refrigerant gas without removing or adding heat. adiabatic curve: The curve obtained by plotting pressure against volume in the adiabatic equation. adiabatic demagnetization: A method of obtaining very low temperatures. A paramagnetic salt is cooled to 1K by liquid helium. The salt is magnetized under isothermal conditions and then magnetized under adiabatic conditions. As a result the temperature falls. Temperatures below 10-2K can be obtained this way. adiabatic efficiency: [1] Of a steam engine or turbine, the ratio of the work done per unit mass of steam to the available energy represented by adiabatic heat drop. [2] Of a compressor, the ratio of that work required to compress a gas adiabatically to the work actually done by the compressor piston or impeller. adiabatic engine: An engine which is very efficient in transferring combustion heat to those parts of the engine which are being cooled by the flow of anti-freeze coolant -- thus maintaining an even temperature of the engine. In this way the engine is warm enough for efficient running and it does not overheat. adiabatic equation: The equation PV = constant, expressing the law of variation of pressure (P) with the volume (V) of a gas during an adiabatic change, being the ratio of the specific heat of the gas at constant pressure to that at constant volume. The value of is approximately 1.4 for air at standard temperature

and pressure. adiabatic expansion: An adiabatic change in which a substance expands. adiabatic heating: Self-heating effect which occurs in extruder or injection molding barrel from action of rotating screw on polymer melt. Attributed to dissipation of mechanical shear forces as heat. Important in injection molding of rubbers. Also called shear heating.Also see damping

adiabatic lapse rate: The rate of decrease of temperature which occurs when a parcel of air rises adiabatically through the atmosphere. adiabatic process: A process which occurs without interchange of heat with surroundings. adiactinic: Said of a substance which does not transmit photochemically active radiation, e.g., safelights for darkroom lamps. adinole: An argillaceous rock that has undergone albitization during contactmetamorphism. adipo-: Prefix from Latin adeps "fat". A-display: Co-ordinate display on a cathode-ray tube in which a level time base represents distance and vertical deflections of beam indicate echoes. adit:

A horizontal passage or tunnel into a mine. adjacent channel: A channel whose frequency is immediately above or below that of the required signal. adjust: The action of putting something into its proper alignment or position. It may involve one component (e.g., He adjusted the gasket to fit properly.) or a series of components (e.g., He adjusted the poor idle -- might mean he set the ignition timing, adjusted the carburetor screws, changed the choke setting, cleaned or replaced the spark plugs, etc.)Also see tweak

adjustable: A characteristic of something that can be changed, removed, or give different properties.Also see height adjustable steering column

adjustable bottom bracket: [1] A component of a bicycle through which the crank fits. It has two bearing cups on either side. One cup is fixed in place while the other is removable or adjustable. [2] This is the older type of bottom bracket before sealed cartridge bottom brackets became prevalent. The adjustable bottom bracket requires fixed and adjustable cup tools to properly tension the bearings. The bearings are not sealed, but they're easily accessible for cleaning and lubrication.Also see bottom bracket

adjustable cup: The left-hand cup in a bottom bracket of a bicycle, used in adjusting the bottom bracket bearings and removed during bottom bracket overhaul. The other cup is the fixed cup. adjustable off-idle air bleed:

Some emissions-era Rochester carburetors have a separate air passage to bleed air past an adjustment screw into the idle system. this screw is preset by the factory to produce precise off-idle air/fuel mixture ratios to meet emission-control requirements. adjustable part throttle: (APT) a supplementary circuit on some carburetors that can be adjusted to control part-throttle mixtures more accurately than a fixed orifice. The APT detours around the main jet, going directly from the float bowl to the discharge nozzle feed well. adjustable-pitch propeller:See propeller

adjustable-port proportioning valve: Air and fuel valves for oil or gas burners, motor operated in unison by automatic temperature-control equipment. adjustable rocker arm: A type of rocker arm with an adjusting nut that can be tightened or loosened to adjust valve lash. adjustable shock:See adjustable shocks

adjustable shock absorbers: Shocks with adjustable jounce and rebound characteristics can be stiffened to compensate for wear or to fine tune a suspension for a particular application such as rough roads, heavy loads, or racing. adjustable shocks: Shock absorbers which can compensate for varying needs of stiffness or softness. Manual types (especially on motorcycles) require that you physically make the adjustment from one level to another. Automatic types are controlled by a computer as it senses particular changes in road


adjustable spanner: British term for adjustable wrench. adjustable steering:See height adjustable steering column

adjustable steering column:See height adjustable steering column

adjustable variable exhaust port: A device used on two-stroke engines which automatically alters or varies the exhaust port size. adjustable wrench: A crescent wrench or pipe wrench. A tool which has a fixed jaw and a movable jaw which is controlled by a spiral gear. It is used to install or remove bolts and nuts of various sizes. The wrench itself comes in a variety of lengths and jaw sizes. A crescent wrench has smooth jaws while a pipe wrench has serrated jaws. British term is "adjustable spanner." adjusted:See factory adjusted

adjuster: A device for moving something into the correct position or into a different position such as a seat adjuster.Also see automatic adjuster

automatic wear adjuster brake adjuster horizontal adjuster jet adjuster ride-height adjuster

adjuster cam: A device for moving the shoes on drum brakes closer to the drum itself so that there is less travel when the brakes are applied. adjusting:Also see electrode adjusting tool headlight adjusting screw self-adjusting

adjusting gage:See adjusting gauge

adjusting gauge: A tool used to determine the small distance between two parts so that they can be brought within specifications. adjusting screw: A small screw usually found on carburetors, brakes, or headlights which change the way something operates, such as increasing or decreasing the amount of fuel entering the engine; or changing the idle speed; or tightening up the brakes; or changing the setting on rocker arms; or the level of the headlights.Also see headlight adjusting screw tappet adjusting screw valve adjusting screw

adjusting shim: A thin washer or plate which reduces or increases the clearance between two components (depending upon where they are placed). While some valves are adjusted by screws on the rocker arm, others are set by inserting a shim to make the same adjustment.

adjusting sleeve: A small threaded cylinder on the end of the tie rod which shortens or lengthens the rod to make changes in the toe-in and toe-out. adjusting spanner:See brake adjusting spanner

adjusting tool:Also see brake adjusting tool electrode adjusting tool

adjusting wrench:See brake adjusting wrench

adjustment: [1] Changing or modifying the position or alignment of two components. [2] The distance of travel that a component has.Also see fore and aft adjustment idle mixture adjustment screw idle speed adjustment

adjustment screw:See idle mixture adjustment screw

Adler: The brand name of a vehicle. With required application the 1925-48 models are classic cars. admiralty brass:See Tobin bronze

admission: The point in the working cycles of a steam or internal-combustion engine at which the intake valve allows entry of the working fluid into the cylinder. admittance:

Property which permits the flow of current under the action of a potential difference. The reciprocal of impedance. a-dos:See dos-a-dos

Adrastea: A tiny natural satellite of Jupiter, discovered in 1979 by the Voyager 2 mission. Distance from the planet 129,000 km; diameter 24 km. A-drier:See a-dryer

ADS: Abbreviation for air data system. A-dryer: A paint dryer which has the heating elements below the paint drying line. ADS: Acronym for "Association of Diesel Specialists". adsorbent: Substance with the property to hold molecules of fluids without causing a chemical or physical change. adsorption: The bonding that takes place when a gas or vapor comes into contact with a solid. The opposite is desorption. adsorption canister:See activated carbon canister


A milky or bluish sheen shown by moonstone. advance: [1] The act of changing the ignition timing so that the spark occurs earlier in the cycle. The opposite is retard. [2] It may refer to the device which makes this adjustment. [3] The length of railway track beyond a signal which is covered by that signalAlso see angle of advance automatic advance centrifugal advance electronic spark advance ignition advance mechanical advance ported vacuum advance spark advance speed control vacuum advance vacuum advance

advance capsule:See vacuum advance

advance curve: As the speed of the engine increases the ignition advance also increases. On paper, a pattern is drawn as a curve to represent this relationship. advanced: [1] A condition in which something occurs early. [2] A product which is on the cutting edge of technology and shows the latest in new ideas and concepts. advanced gas-cooled reactor: (AGR) Carbon-dioxide-cooled, graphite-moderated reactor using slightly enriched uranium oxide fuel clad in stainless steel, in use in the UK. advanced intelligent network: A form of intelligent network, developed in the US from 1987 onward, in which signalling, software, and accounting procedures are designed to allow service providers to compete freely for network users' business.

advanced mobile phone system: (AMPS) The American forerunner of the UK total access communications system. Developed by Bell in 1978, AMPS like TACS, is an analog cellular system using frequency modulation. advanced rim taper: A rim where both bead seats are tapered 5. advance mechanism:See vacuum advance mechanism

advance metal: Copper-base alloy with 45% nickel. advance spring: A small spring which pulls the advance weight back.See picture in advance weight

advance unit:See vacuum advance unit

advance weight: One of two small weights located in a centrifugal advance assembly.

advance workings:

In flat seams, mining in which the whole face is carried forward, no support pillars being left. advantage ratio: Ratio between the radiation dosage received at any point in a nuclear reactor and that of a reference position. advection: The transference of any quantity by horizontal motion of the air. advection fog: Fog produced by the advection of warm moist air across cold ground. advection layer: The region immediately adjacent to the event horizon where matter is being continuously pulled into the black hole. advertising: A colloquial term for a police car with its emergency lights flashing. Ae: The transformation temperature at equilibrium of the phase changes in iron and steel, subscripts indicating the designated change. Also called A. AE: Abbreviation for automatic exposure. AEA: Acronym for "Automotive Electric Association" or "Automotive Electronic Association". aeolian tone: A musical note set up by vortex action on a stretched string when it is placed in a stream of air.Also see

Strouhal number

aeolotropic: Having physical properties which vary with direction or position.Also see anisotropic

AERA: Acronym for "Automotive Engine Rebuilders Association." aeration: A foaming of a liquid because air has been introduced into the fluid. When it occurs in certain liquids, it decreases the efficiency of the liquid. aeration test burner: (ATB) Burner for measuring the combustion characteristics of commercial gases. aerial: British term for antenna.Also see retractable aerial whip aerial

aerial bunched conductors: (ABC) Method of power transmission where the three conductors are twisted into a thicker insulated cable. More expensive but better at surviving blizzard conditions than normal separate conductors. aerial fog: Fog caused by exposure of portions of the film to air in the processing machine. aerial radiometric surveying: Use of low-flying aircraft to measure gamma-ray intensity due to natural radioactive emissions or radioactive contamination over large areas. Scintillators are used with photomultipliers whose signals are fed to multichannel analyzers to distinguish the energies of the gamma rays

received from a wide area; typically 90% of the gamma rays can be recorded from an area with linear dimensions about five times the aircraft's height above the ground. Also called airborne radiometric surveying. aerial ropeway: An apparatus for the overhead transport of materials in carriers running along an overhead cable or cables supported on towers. aerial surveying: A process of surveying by photographs taken from the air, the photographs being of two types: 1. those giving a vertical or plan view; 2. those giving an oblique or bird's-eye view.Also see vertical aerial photograph oblique aerial photograph

AERO: Abbreviation for "Air Education and Recreation Organization" in the UK. aero-: Prefix from Greek aer () indicating "air". aero-acoustics: Branch of acoustics that treats sound generation and transmission by fluid flow. aerobar: An extension to bicycle handlebars which project forward to give the rider an alternate riding position and a lower, more aerodynamic position. His elbows rest in the pads while he grabs the upright ends of the bars. Aerobars were popularized by triathletes and Greg LeMond.

aerobars: Sometimes referred to as Tri bars. Aerobars popularized by triathletes and Greg LeMond, are attached to handlebars in order to provide a rider with a lower, more aerodynamic position. aerobic sealer: A substance (such as room temperature vulcanizing (RTV), a common silicone rubber sealing compound) that requires the presence of oxygen to hold parts together.Also see anaerobic sealer

aerodynamic: The efficient flow of air around an object. aerodynamic balance: [1] A balance, usually but not necessarily in a wind tunnel, designed for measuring aerodynamic forces or moments. [2] Means for balancing air loads on flying control surfaces, so that the pilot need not exert excessive force, particularly as speed increases. The principle is to use aerodynamic forces, either directly on a portion of the control surface ahead of the hinge line or indirectly through a small auxiliary surface with a powerful moment arm, to counterbalance the main airloads. An example of the first is the horn balance, and of the second the balance tab. aerodynamic braking: Use of a planet's atmosphere to reduce the speed of space vehicles. aerodynamic center: The point about which the pitching moment coefficient is constant for a range of airfoil incidence. aerodynamic coefficient: A non-dimensional measure of aerodynamic force, pressure, or moment that expresses the characteristics of a particular shape at a given incidence to the airflow. Typically the lift coefficient is given by CL=L/VS, where L is the lift, is the air density, V is the air speed, and S is a typical area of

the body (e.g., wing area). Similarly for drag coefficient. aerodynamic damping: The suppression of oscillations by the inherent stability of a aircraft or of its control surfaces. aerodynamic drag: The resistance of the air to forward movement, sometimes called "air resistance." This is a factor of the shape of the vehicle (drag coefficient and frontal area), the objects which stick out (i.e., mirrors, mufflers, bumpers), the amount of turbulence at the rear of the vehicle, the nature of the vehicle's skin surface, and the amount of air going through the vehicle for cooling and ventilation. The faster you go, the greater the air friction (air friction = velocity x velocity). The faster you go, the greater the amount of power needed to overcome this drag (power = velocity x velocity x velocity). aerodynamic heating: The heating of a vehicle passing through the atmosphere, caused by friction and compression of air (or other gas). aerodynamics: The study of the flow of air as it passes over and around a moving object as well as the forces which the air makes on the object. An airplane, for instance, needs positive lift to get it airborne and negative lift to help it land. Thus the shape of a land vehicle (car, bicycle, etc.) either promotes positive or negative lift. Race cars may use spoilers and wings (air foils) to control lift. In vehicle design, the airflow is monitored in a wind tunnel. As well, aerodynamics also studies the most efficient shapes for increased speed and fuel economy. aerodynamic sound:See fl