The square of the standard deviation.
Related Terms |
PSID
pounds per square inch differential.
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EMISSION SPECTROMETER
Works on the basis that atoms of metallic and other particular elements emit light at characteristic wavelengths when they are excited in a flame, arc, or spark. Excited light is directed through an entrance slit in the spectrometer. This light penetrates the slit, falls on a grate, and is dispersed and reflected. The spectrometer is calibrated by a series of standard samples containing known amounts of the elements of interest. By exciting these standard samples, an analytical curve can be established which gives the relationship between the light intensity and its concentration in the fluid.
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PSIG
pounds per square inch gauge (PSIA - 14.696).
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FABRICATION INTEGRITY POINT
The differential gas pressure at which the first stream of gas bubbles are emitted from a wetted filter element under standard test conditions.
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ISO VISCOSITY GRADE
A number indicating the nominal viscosity of an industrial fluid lubricant at 40°C (104°F) as defined by ASTM Standard Viscosity System for Industrial Fluid Lubricants D 2422. Essentially identical to ISO Standard 3448.
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HACK
A chronometer which has failed to meet the exacting require- ments of a standard chronometer, and is used for timing observations of celestial bodies, regulating ship's clocks, etc. A comparing watch, which may be of high quality, is normally used for timing celestial observations, the watch being compared with the chronometer, preferably both before and after observations. Sometimes called HACK CHRONOMETER.
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ATMOSPHERIC PRESSURE
Pressure exerted by the atmosphere at any specific location. (Sea level pressure is approximately 14.7 pounds per square inch absolute.)
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PATCH TEST
A method by which a specified volume of fluid is filtered through a membrane filter of known pore structure. All particulate matter in excess of an 'average size', determined by the membrane characteristics, is retained on its surface. Thus, the membrane is discolored by an amount proportional to the particulate level of the fluid sample. Visually comparing the test filter with standard patches of known contamination levels determines acceptability for a given fluid.
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VAPOR PRESSURE-REID (RVP)
Measure of the pressure of vapor accumulated above a sample of gasoline or other volatile fuel in a standard bomb at 100°F (37.8°C). Used to predict the vapor locking tendencies of the fuel in a vehicle's fuel system. Controlled by law in some areas to limit air pollution from hydrocarbon evaporation while dispensing.
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SAYBOLT UNIVERSAL VISCOSITY (SUV)
The time in seconds required for 60 cubic centimeters of a fluid to flow through the orifice of the Standard Saybolt Universal Viscometer at a given temperature under specified conditions. (ASTM Designation D 88.
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