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  2. Liquid nitrogen - Wikipedia

    en.wikipedia.org/wiki/Liquid_nitrogen

    Because the liquid-to-gas expansion ratio of nitrogen is 1:694 at 20 °C (68 °F), a tremendous amount of force can be generated if liquid nitrogen is vaporized in an enclosed space. In an incident on January 12, 2006 at Texas A&M University , the pressure-relief devices of a tank of liquid nitrogen were malfunctioning and later sealed.

  3. Units of textile measurement - Wikipedia

    en.wikipedia.org/wiki/Units_of_textile_measurement

    Den is a direct measure of linear density. [5] dtex (deci-tex): Grams per 10,000 metres of yarn. Dtex is a direct measure of linear density. [5] gr/yard: Grains per yard of yarn. Gr/yard is a direct measure of linear density, but is rarely used in the modern textile industry. ECC or NeC or Ne (English Cotton Count): The number of 840 yd lengths ...

  4. Moisture analysis - Wikipedia

    en.wikipedia.org/wiki/Moisture_analysis

    It is necessary to measure temperatures of both the condensation and evaporation, because the dew point is the equilibrium temperature at which water both condense and evaporate at the same rate. When cooling the mirror, the temperature keeps dropping after it has reached the dew point thus, the condensation temperature measurement is lower ...

  5. BET theory - Wikipedia

    en.wikipedia.org/wiki/BET_theory

    This may be performed using adsorption isotherms measured in different ways, including the adsorption of water vapour at temperatures near ambient, and adsorption of nitrogen at 77 K (the boiling point of liquid nitrogen). Different methods of measuring cement paste surface areas often give very different values, but for a single method the ...

  6. Cold trap - Wikipedia

    en.wikipedia.org/wiki/Cold_trap

    In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases (hydrogen, oxygen, and nitrogen) into a liquid or solid. [ 2 ] [ needs update ] The most common objective is to prevent vapors being evacuated from an experiment from entering a vacuum pump where they would condense and contaminate it.

  7. List of viscosities - Wikipedia

    en.wikipedia.org/wiki/List_of_viscosities

    For liquid, the dynamic viscosity is usually in the range of 0.001 to 1 Pascal-second, or 1 to 1000 centiPoise. The density is usually on the order of 1000 kg/m^3, i.e. that of water. Consequently, if a liquid has dynamic viscosity of n centiPoise, and its density is not too different from that of water, then its kinematic viscosity is around n ...

  8. Specific weight - Wikipedia

    en.wikipedia.org/wiki/Specific_weight

    The specific weight, also known as the unit weight (symbol γ, the Greek letter gamma), is a volume-specific quantity defined as the weight W divided by the volume V of a material: = / Equivalently, it may also be formulated as the product of density, ρ, and gravity acceleration, g: = Its unit of measurement in the International System of Units (SI) is newton per cubic metre (N/m 3), with ...

  9. Lifting gas - Wikipedia

    en.wikipedia.org/wiki/Lifting_gas

    The gaseous state of water is lighter than air (density 0.804 g/L at STP, average molecular mass 18.015 g/mol) due to water's low molar mass when compared with typical atmospheric gases such as nitrogen gas (N 2). It is non-flammable and much cheaper than helium. The concept of using steam for lifting is therefore already 200 years old.