| A Filtering: Mimics human ear`s frequency response. |
| A/D Converter: (Also A/D or ADC) Short for analog-to-digital converter. Converts real-world analog signals into a digital format that can be processed by a computer. |
| AAO : Army acquisition objective [Military] |
| ABCQ : Associaco Brasileira de Contrele de Qualidade (Brazilian Association for Quality Control)
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| Abiotic: not biotic; not formed by biologic processes. |
| Abnormal Failure: An artificially induced failure of a component, usually as a result of "abnormals" testing for regulatory agency safety compliance. |
| ABNT: Associaco Brasileira de Normas Tecnicas (Brazilian Association for Technical Standardization)
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| Abrasion Resistance: The ability of a material to resist mechanical wear. |
| Absolute Pressure Transducer: A transducer that has an internal reference chamber sealed at or close to 0 psia (full vacuum) and normally provides increasing output voltage for increases in pressure. |
| Absolute Pressure: Gage pressure plus atmospheric pressure. |
| Absolute viscosity (Dynamic) : The force in newton required to move a fluid layer of one square meter area and a thickness of one meter with a velocity of one meter per second.
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| Absolute Zero: Temperature at which thermal energy is at a minimum. Defined as 0 Kelvin, calculated to be -273.15 ?C or -459.67?F. |
| Absorbed Dose: The amount of a chemical that enters the body of an exposed organism. |
| Absorption Factor: The fraction of a chemical making contact with an organism that is absorbed by the organism. |
| Absorption spectrum: Spectrum of electromagnetic radiation absorbed by matter when radiation of all frequencies is passed through it.
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| Absorption(of water vapor): Retention (of water vapor) by penetration into the bulk of a material. |
| Absorption: The penetration of atoms, ions, or molecules into the bulk mass of a substance.
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| AC Linearity: A dynamic measurement of how well an A/D performs. In an ideal A/D converter, a pure sine wave on the analog input appears at the digital output as a pure (sampled) sine wave. In the real world, however, spurious signals due to nonlinear distortion within the A/D appear in the digital output. These anomalies are usually combinations of harmonics of the fundamental and intermodulation products, produced when the fundamental and its harmonics beat with the sampled frequency. |
| ACC: Adaptive Cruise Control; the ACC system scans the area ahead of a car for objects - mainly other cars - and applies the brakes automatically if a collision is likely to occur.
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| Acceleration: The first derivative of velocity with respect to time. Units expressed in "g". |
| Accelerometer: A transducer which converts mechanical motion into an electrical signal that is proportional to the acceleration value of the motion.tec |
| acceptable daily Intake (ADI). Estimate of the largest amount of chemical to which a person can be exposed on a daily basis that is not anticipated to result in adverse effects (usually expressed in mg/kg/day). |
| Access Protocol: A defined set of procedures that function as an interface between a user and a network and enable the user to employ the services of that network. |
| Accuracy: The combined error of nonlinearity, repeatability, and hysteresis expressed as a percent of full scale output. |
| ACE : Automated Calibration Equipment
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| Achromatic Lens: Lens for which all light colors have the same focal length.
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| Acidified: The addition of an acid (usually nitric or sulfuric) to a sample to lower the pH below 2.0. The purpose of acidification is to `fix? a sample so it won?t change until it is analyzed |
| Acoustics: The degree of sound. The nature, cause, and phenomena of the vibrations of elastic bodies; which vibrations create compressional waves or wave fronts which are transmitted through various media, such as air, water, wood, steel, etc. |
| Acquisition Time: This term relates to sampling A/Ds which utilize a track/hold amplifier on the input to acquire and hold the analog input signal. Acquisition time is the time required by the T/H amplifier to settle to its final value after it is placed in the track module. |
| ACRS: Advisory Committee on Reactor Safeguards.tec |
| Activated Carbon: Adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). These particles or granules have a high capacity to selectively remove certain trace and soluble materials from water. |
| Active Filter: An active filter is one that uses active devices such as operational amplifiers to synthesize the filter response function. This technique has an advantage at high speeds because the need for inductors is eliminated.te |
| Active Transport: An energy-expending mechanism by which a cell moves a chemical across the cell membrane from a point of lower concentration to a point of higher concentra- tion, against the diffusion gradient. |
| Actual Ratio, Haskel The number obtained by dividing the area of the air barrel I.D. by the cross - sectional area of the plunger/piston exposed to the fluid |
| Acute Exposure: single exposure to a toxic substance which results in severe biological harm or death. Acute exposures are usually characterized as lasting no longer than a day. |
| Acute Toxicity: The ability of a substance to cause poisonous effects resulting in severe biological harm or death soon after a single exposure or dose. Also, any severe poisonous effect resulting from a single short-term exposure to a toxic substance. |
| Adaptive Equalization: Receiver technique that compensates for distortions in transmission media. |
| Address: The label or number identifying the memory location where a unit of information is stored. |
| Adhesion: (1) the attractive force between adjacent surfaces in a frictional contact; (2) the state in which two surfaces are held together by interfacial forces.
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| Adiabatic Efficiency: Ratio between measured shaft power and the adiabatic compression power, referring to measured mass flow (0100). |
| ADN: (Advanced Digital Network)
Usually refers to a 56Kbps leased-line.
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| ADSL - Asymmetrical DSL The data rate from the ISP is greater than the data rate to the ISP. For example, ADSL would deliver 6 million bits per second (6Mb/s) to the home, but only 384 thousand bits per second (384Kb/s) from the home to the ISP.
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| ADSL: (Asymmetric Digital Subscriber Line)
A DSL line where the upload speed is different from the download speed. usually the download speed is much greater. |
| Adsorbate: The material being removed by the adsorption process |
| Adsorbent: The material (activated carbon) that is responsible for removing the undesirable substance in the adsorption process. |
| Adsorption: The retention of atoms, ions, or molecules onto the surface of another substance.
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| Advection: The process of transfer of fluids (vapors or liquid) through a geologic formation in response to a pressure gradient that may be caused by changes in barometric pressure, water table levels, wind fluctuations, or infiltration.
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| AEC: Atomic Energy Commission, 1947-1974. Broken up in 1974 into the Energy Research and Development Administration (ERDA) and the Nuclear Regulatory Commission (NRC). EDRA later became the Department of Energy. |
| Aeration: The process of bringing air into contact with a liquid (typically water), usually by bubbling air through the liquid, spraying the liquid into the air, allowing the liquid to cascade down a waterfall, or by mechanical agitation. Aeration serves to (1) strip dissolved gases from solution, and/or (2) oxygenate the liquid. The rate at which a gas transfers into solution can be described by Ficks First Law.
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| Aerobic: Able to live, grow, or take place only when free oxygen is present.
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| Aerosol: A suspension of liquid or solid particles in gas. |
| Aggregate: Coarse mineral material (e.g., sand, gravel) that is mixed with either cement to form concrete or tarry hydrocarbons to form asp |
| Agrochemical: Synthetic chemicals (pesticide and fertilizers) used in agricultural production. |
| Air Actuator: An elastomeric bellow with specially designed metal end closures used in place of pneumatic or hydraulic cylinders. A device which induces action or motion with compressed air being the medium through which the power is transmitted. |
| Air Amplifier: A component on a compressed air line designed to increase in magnitude the flow by releasing small amounts of compressed air at high velocity through an internal, ring shaped nozzle. This column of air released through the front creates a vacuum behind, thus pulling ambient air through the rear and pushing ambient air in fro |
| Air Cycling valve,Haskel The air cycling assembly used to direct the flow of air alternately to one side of the air piston and then the other, to produce the reciprocating(back and forth) motion needed to make the pump function |
| Air Cylinder: A component made up of a cylinder barrel, end covers, a piston rod, a steel or stainless steel piston. A device which induces action or motion with compressed air being the medium through which the power is transmitted. |
| Air Dryer: A device for drying compressed air by means of condensation obtained by over-compression or cooling, absorption, adsorption or a combination of the above methods.
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| Air Gap: An open vertical drop, or vertical empty space, that separates a drinking (potable) water supply to be protected from another water system in a water treatment plant or other location. This open gap prevents the contamination of drinking water by backsiphonage or backflow because there is no way raw water or any other water can reach the drinking water. |
| Air Motor: Is a compact, low mass unit giving smooth, non-vibrating power. Several types include vane, piston, percussion and turbine type motors
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| Air Padding: Pumping dry air into a container to assist with the withdrawal of a liquid or to force a liquefied gas such as chlorine out of a container. |
| Air Pressure Amplifier An air pump that is driven by part of the incoming compressed air supply , enabling it to cycle and pump the balance of the supply to a higher output pressure. |
| Air Receiver: A receptacle which serves to store compressed air for heavy demands in excess of compressor capacity.
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| Air Stripping: A treatment process used to remove dissolved gases and volatile substances from water. Large volumes of air are bubbled through the water being treated to remove (strip out) the dissolved gases and volatile substances. |
| Alarm Contact: A switch that operates when some pre-set low, high or abnormal condition exists |
| Alarm, Deviation: Warns that a process has exceeded or fallen below a certain range around the set point. Alarms can be referenced at a fixed number of degrees, plus or minus, from set point.
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| AlGaAs : Aluminum gallium arsenide |
| Algae: Microscopic plants which contain chlorophyll and live floating or suspended in water. They also may be attached to structures, rocks or other submerged surfaces. They are food for fish and small aquatic animals. Excess algal growths can impart tastes and odors to potable water. Algae produce oxygen during sunlight hours and use oxygen during the night hours. Their biological activities appreciably affect the pH and dissolved oxygen of the water |
| Algal Bloom: Sudden, massive growths of micro- scopic and macroscopic plant life, such as green or blue- green algae, which develop in lakes and reservoirs |
| Algicide: Any substance or chemical specifically formulated to kill or control algae |
| Alias Frequency : A false lower-frequency component that occurs in analog data that is sampled from data that is originally digitized at too low a frequency.
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| Aliased Imaging: This is a technique, commonly applied to Direct Digital Synthesis, for using intentional aliasing as a source of high-frequency signals. |
| Aliasing: In a sampled data system, the analog input must be sampled at a rate of at least twice the bandwidth of the signal in order to avoid loss of data (Nyquist Theorem). Adhering to the Nyquist Theorem prevents in-band "alias" signals, which are beat frequencies between the analog signal and the sampling clock that inherently occur. |
| Aliphatic Hydroxy Acids: Organic acids with carbon atoms arranged in branched or unbranched open chains rather than in rings. |
| Alloy 11: A compensating alloy used in conjunction with pure copper as the negative leg to form extension wire for platinum-platinum rhodium thermocouples Types R and S. |
| Alloy 200/226: The combination of compensating alloys used with tungsten vs. tungsten 26% rhenium thermocouples as extension cable for applications under 200?C. |
| Alloy 203/225: The combination of compensating alloys used with tungsten 3% rhenium vs. tungsten 150 rhenium thermocouples as extension cable for applications under 200?C. |
| Alloy 405/426: The combination of compensating alloys used with tungsten 5% rhenium vs. tungsten 26% rhenium thermocouples as extension cable for applications under 870?C. |
| Alpha Decay: The emission of a nucleus of a helium atom from the nucleus of an element, generally of a heavy element, in the process of its radioactive decay. |
| Alpha Particle: The nuclei of a helium (with two neutrons and two protons each) that are discharged by radioactive decay of many heavy elements, such as uranium-238 and plutonium-239. |
| Alpha Radiation: Radiation consisting of helium nuclei (atomic wt. 4, atomic number 2) that are discharged by radioactive disintegration of some heavy elements, including uranium-238, radium-226, and plutonium-239. |
| Alphanumeric: A character set that contains both letters and digits. |
| Alumel: An aluminum nickel alloy used in the negative leg of a Type K thermocouple (Trade name of Hoskins Manufacturing Company). |
| AM: Amplitude Modulation |
| Ambient Compensation: The design of an instrument such that changes in ambient temperature do not affect the readings of the instrument. |
| Ambient Conditions: The conditions around the transducer (pressure, temperature, etc.) |
| Ambient Pressure: Pressure of the air surrounding a transducer. |
| Ambient Temperature: The average or mean temperature of the surrounding air which comes in contact with the equipment and instruments under test.
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| Ammeter: An instrument used to measure current.
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| Amontons Law: States that the pressure of a gas, at constant volume, varies directly with the absolute temperature.
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| Ampere (amp): A unit used to define the rate of flow of electricity (current) in a circuit; units are one coulomb (6.25 x 108 electronics) per second. |
| Amperometric Titration: A means of measuring concentrations of certain substances in water (such as strong oxidizers) based on the electric current that flows during a chemical reaction |
| Amplifier: A device which draws power from a source other than the input signal and which produces as an output an enlarged reproduction of the essential features of its input. |
| Anaerobic: Able to live, grow, or take place where free oxygen is not present.
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| Analog Ground: In high-speed acquisition applications, system ground is generally physically separated into analog and digital grounds in an attempt to suppress digital switching noise and minimize its effect on noise-sensitive analog signal processing circuitry. Input signal conditioners, amplifiers, references, and A/D converters are usually connected to analog ground.
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| Analog Output: A voltage or current signal that is a continuous function of the measured parameter. |
| Analog-to-Digital Converter (A/D or ADC) A device or circuit that outputs a binary number corresponding to an analog signal level at the input.
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| Analyzer An instrument that provides quantitative and qualitative measureements of the composition of a mixture or compound. |
| Anechoic Chamber : An enclosure especially designed with walls that absorb sound or radiation, creating an essentially free-field environment for testing.
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| Anemometer: An instrument for measuring and/or indicating the velocity of air flow.
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| Angle of Incidence: Angle between direction of motion of waves and a line perpendicular to surface the waves are striking
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| Angle of Reflection: Angle between direction of motion of waves and a line perpendicular to surface the waves are reflected from.
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| Angle of Refraction: Angle between direction of motion of waves and a line perpendicular to surface the waves have been refracted from.
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| Angstrom: Ten to the minus tenth meters (10-10) or one millimicron, a unit used to define the wave length of light. Designated by the symbol ?. |
| Angular Frequency: The motion of a body or a point moving circularly, referred to as the circular frequency O which is the frequency in cycles per second (cps) multiplied by the term (2) and expressed in radians per second (2pf).
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| Anion: A negatively charged ion (Cl-, NO3-, S2- etc.) |
| Anode: The positive pole or electrode of an electrolytic system, such as a battery. The anode attracts negatively charged particles or ions (anions). |
| Anodic Protection: A technique to reduce the corrosion rate of a metal by polarizing it into its passive region, where dissolution rates are low.
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| Anodizing : Forming a conversion coating on a metal surface by anodic oxidation; most often applied to aluminum.
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| ANSI: American National Standards Institute. |
| Anti-reset Windup: This is a feature in a three-mode PID controller which prevents the integral (auto reset) circuit from functioning when the temperature is outside the proportional band.
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| Antimatter: Material made from antifermions. We define the fermions that are common in our universe as matter and their antiparticles as antimatter. In the particle theory there is no a priori distinction between matter and antimatter. The asymmetry of the universe between these two classes of particles is a deep puzzle for which we are not yet completely sure of an explanation. |
| Antiparticle: For every fermion type there is another fermion type that has exactly the same mass but the opposite value of all other charges (quantum numbers). This is called the antiparticle. For example, the antiparticle of an electron is a particle of positive electric charge called the positron. Bosons also have antiparticles except for those that have zero value for all charges, for example a photon or a composite boson made from a quark and its corresponding antiquark. In this case there is no distinction between the particle and the antiparticle, they are the same object. |
| Apparent Power: A value of power for AC circuits that is calculated as the product of RMS current times RMS voltage, without taking the power factor into account. |
| Applet: A small Java program that can be embedded in an HTML page. Applets differ from full-fledged Java applications in that they are not allowed to access certain resources on the local computer, such as files and serial devices (modems, printers, etc.), and are prohibited from communicating with most other computers across a network. The common rule is that an applet can only make an Internet connection to the computer from which the applet was sent. |
| Application Program: A computer program that accomplishes specific tasks, such as word processing. |
| Appurtenance: Machinery, appliances, structures and other parts of the main structure necessary to allow it to operate as intended, but not considered part of the main structure. |
| Archie (software): A tool (software) for finding files stored on anonymous FTP sites. You need to know the exact file name or a substring of it. By 1999 Archie had been almost completely replaced by web-based search engines. back when FTP was the main way people moved files over the Internet archie was quite popular. |
| Archimedes principle: The buoyant force is equal to the weight of the displaced fluid.
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| ARP: Address Resolution Protocol. An Internet protocol which runs on ethernets and token rings and maps Internet addresses to MAC addresses. |
| ARPANet (Advanced Research Projects Agency Network)
The precursor to the Internet. Developed in the late 60?s and early 70?s by the US Department of Defense as an experiment in wide-area-networking to connect together computers that were each running different system so that people at one location could use computing resources from another location. |
| ASCII: American Standard Code for Information Interchange. A seven or eight bit code used to represent alphanumeric characters. It is the standard code used for communications between data processing systems and associated equipment.
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| Aseptic: Free from the living germs of disease, fermentation or putrefaction. Sterile. |
| ASIC: Application specific integrated circuit. |
| ASME: American Society of Mechanical Engineers. |
| Assembler: A program that translates assembly language instructions into machine language instructions. |
| Assembly Language: A machine oriented language in which mnemonics are used to represent each machine language instruction. Each CPU has its own specific assembly language.
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| ASTM: American Society for Testing and Materials. |
| Astrophysics: The physics of astronomical objects such as stars and galaxies. |
| Asymmetry Potential: The potential developed across the glass membrane with identical solutions on both sides. Also a term used when comparing glass electrode potential in pH 7 buffer. |
| Asymptote: A line that is considered to be the limit to a curve. As the curve approaches the asymptote, the distance separating the curve and the asymptote continues to decrease, but the curve never actually intersects the asymptote.
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| Asynchronous Communication: This method of transferring data does so without a specific timing mechanism between the two communicating parties. The party receiving data is not expecting more data at any set interval |
| ATC: Automatic Temperature Compensation.
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| Atmospheric Pressure: Weight of the earths atmosphere over a unit area of the earths surface, measured with a mercury barometer at sea level. which corresponds to the pressure required to lift a column of mercury 760 mm. |
| Atomic Number : (symbolized Z): The number of protons in a nucleus. It determines the chemical properties of an element.
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| Atomic Weight: The nominal atomic weight of an isotope is given by the sum of the number of neutrons and protons in each nucleus. The exact atomic weight differs fractionally from that whole number because neutrons are slightly heavier than protons and the mass of the nucleus is also affected by the binding energy.
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| Attenuation Coefficient : The rate of optical power loss relative to the distance along the fiber.
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| Attenuation: Power loss in an electrical system. In cables, generally expressed in dB per unit length.
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| Auto-Zero: An automatic internal correction for offsets and/or drift at zero voltage input. |
| Automatic Reset: 1. A feature on a limit controller that automatically resets the controller when the controlled temperature returns to within the limit bandwidth set. 2. The integral function on a PID controller which adjusts the proportional bandwidth with respect to the set point to compensate for droop in the circuit, i.e., adjusts the controlled temperature to a set point after the system stabilizes.
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| Autopolarity : The ability of an instrument to measure and display an input of either polarity without switching the input leads.
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| Autoranging Time : For instruments with autoranging capability, the time interval between application of a step input signal and its display, including the time for determining and changing to the correct range.
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| Autotrophic: Designating or typical of organisms that derive carbon for the manufacture of cell mass from inorganic carbon (carbon dioxide).
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| Available Chlorine: A measure of the amount of chlorine available in chlorinated lime, hypochlorite compounds, and other materials that are used as a source of chlorine when compared with that of elemental (liquid or gaseous) chlorine |
| Avalanche Breakdown : A breakdown that is caused by the cumulative multiplication of charge carriers through field-induced impact ionization.
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| Avogadros Law: States that equal volumes of all gases under the same conditions of pressure and temperature contain the same number of molecules.
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| Avogadros Number: The number of molecules in 1 mole of any substance. Equal to 6.02 x 10^23 molecules.
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| AWG: American Wire Gage.
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| Axial Load: A load applied along or parallel to and concentric with the primary axis.
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Additions/Suggestions/Assistance
