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Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: = where: P is the amount of prism correction (in prism dioptres) c is decentration (the distance between the pupil centre and the lens's optical centre, in millimetres)
Bolometric correction. In astronomy, the bolometric correction is the correction made to the absolute magnitude of an object in order to convert its visible magnitude to its bolometric magnitude. It is large for stars which radiate most of their energy outside of the visible range. A uniform scale for the correction has not yet been standardized.
Z'-factor. The Z'-factor (Z-prime factor) is defined in terms of four parameters: the means ( ) and standard deviations ( ) of both the positive (p) and negative (n) controls ( , , and , ). Given these values, the Z'-factor is defined as: The Z'-factor is a characteristic parameter of the assay itself, without intervention of samples.
In its original and the most general form, the Sellmeier equation is given as. where n is the refractive index, λ is the wavelength, and Bi and Ci are experimentally determined Sellmeier coefficients. These coefficients are usually quoted for λ in micrometres. Note that this λ is the vacuum wavelength, not that in the material itself, which ...
Compressibility factor values are usually obtained by calculation from equations of state (EOS), such as the virial equation which take compound-specific empirical constants as input.
The formula for Volume Correction Factor is commonly defined as: V C F = C T L = exp { − α T Δ T [ 1 + 0.8 α T ( Δ T + δ T ) ] } {\displaystyle VCF=C_{TL}=\exp\{-\alpha _{T}\Delta T[1+0.8\alpha _{T}(\Delta T+\delta _{T})]\}}
Scherrer equation. The Scherrer equation, in X-ray diffraction and crystallography, is a formula that relates the size of sub- micrometre crystallites in a solid to the broadening of a peak in a diffraction pattern. It is often referred to, incorrectly, as a formula for particle size measurement or analysis. It is named after Paul Scherrer.
Meteorological data includes windspeeds which may be expressed as statute miles per hour, knots, or meters per second. Here are the conversion factors for those various expressions of windspeed: 1 m/s = 2.237 statute mile/h = 1.944 knots. 1 knot = 1.151 statute mile/h = 0.514 m/s. 1 statute mile/h = 0.869 knots = 0.447 m/s.
When used to calculate the pressure drop using the US customary units system, the equation is: S p s i p e r f o o t = P d L = 4.52 Q 1.852 C 1.852 d 4.8704 {\displaystyle S_{\mathrm {psi\ per\ foot} }={\frac {P_{d}}{L}}={\frac {4.52\ Q^{1.852}}{C^{1.852}\ d^{4.8704}}}}
Antoine equation. The Antoine equation is a class of semi-empirical correlations describing the relation between vapor pressure and temperature for pure substances. The Antoine equation is derived from the Clausius–Clapeyron relation. The equation was presented in 1888 by the French engineer Louis Charles Antoine [ fr] (1825–1897).