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| Calibration Gas Standard |
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A gas mixture that has been accurately analyzed against a known reference standard. This mixture can be used as a comparative standard for determinations on analytical instruments.
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| Calorie |
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The amount of heat required to raise the temperature of one gram of water at 15°C by one degree Celsius.
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| Carrier Gas |
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The gas which flows through a separation column of a gas chromatograph and propels a sample to a detector.
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| Catalyst |
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A substance which initiates or accelerates a chemical reaction.
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| CAS Number |
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A Chemical Abstract Services numbering system assigned to each new chemical as it is reported in the world’s literature. Virtually every commercially manufactured chemical has been assigned a CAS number which allows it to be easily identified.
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| Celsius |
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A temperature scale that has been set up so that ice melts at 0° and water boils at 100°C.
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| Certificate of Analysis (COA) |
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A printed guarantee by a gas producer that a particular gas has been analyzed to the levels of purity or impurity stated.
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| Certificate of Conformance (COC) |
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A printed guarantee by a gas producer that a particular gas meets a recognized standard.
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| Chromatography |
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An analytical method where a mixture is physically separated into its individual components.
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| Coefficient of Flow (CV) |
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Rate of flow through a regulator or other gas handling device measured in U.S. gallons per minute at 60°F with a pressure differential of 1 psig.
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| Compressed Gas |
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A gas in a container which meets one of the following criteria:
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Contained at pressures exceeding 40 psia at 70°F |
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Contained at pressures exceeding 104 psia at 130°F |
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A flammable liquid having a vapor pressure exceeding 40 psia at 100°F as determined by ASTM D-323-72 |
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| Compressed Gas Association (CGA) |
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A nonprofit technical organization which develops and promotes industry standards for the safe handling, transport and storage of compressed gases.
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| Corrosive |
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The ability of a chemical to attack another substance, causing irreversible damage. The term applies to substances which attack human tissue and other materials it may come in contact.
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| Cracking Pressure |
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The inlet pressure at which a gas begins to flow through a regulator, valve or other pressure-control device.
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| Creep |
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The slow increase in the outlet pressure of a regulator which may be caused by changes in
inlet pressure or failure of the regulator seat.
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| Critical Density |
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The density of a pure substance at its critical point.
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| Critical Point |
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The point of a temperature vs. pressure curve of a pure substance above which a gas cannot exist in both gas and liquid phases.
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| Critical Pressure |
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The pressure at the critical point above which a pure gas cannot be liquefied.
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| Critical Temperature |
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The temperature above which a gas cannot be liquefied by pressure alone.
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| Cryogenic Liquid |
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A liquid having a normal boiling point below -240°F. (-151.1°C).
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| Cryogenic Vessel |
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An insulated container for the storage, transport and dispensing of liquids having a boiling point below -130°F.
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| Cylinder |
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A container designed to safely hold compressed gases and which is designed and tested to meet government specified standards of construction.
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| Density |
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The mass of a substance divided by its volume.
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| Department of Transportation (DOT) |
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Federal agency that regulates the transport of hazardous materials per Title 49, Code of Federal Regulations.
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| Dewar |
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A vessel that is usually portable and is used to contain cryogenic liquids.
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| Dew Point |
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The temperature at which a gas vapor begins to condense as a liquid.
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