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  2. Relative change - Wikipedia

    en.wikipedia.org/wiki/Relative_change

    A percentage change is a way to express a change in a variable. It represents the relative change between the old value and the new one. [6]For example, if a house is worth $100,000 today and the year after its value goes up to $110,000, the percentage change of its value can be expressed as = = %.

  3. Fenske equation - Wikipedia

    en.wikipedia.org/wiki/Fenske_equation

    The Fenske equation in continuous fractional distillation is an equation used for calculating the minimum number of theoretical plates required for the separation of a binary feed stream by a fractionation column that is being operated at total reflux (i.e., which means that no overhead product distillate is being withdrawn from the column).

  4. Volume fraction - Wikipedia

    en.wikipedia.org/wiki/Volume_fraction

    In chemistry and fluid mechanics, the volume fraction is defined as the volume of a constituent Vi divided by the volume of all constituents of the mixture V prior to mixing: [ 1] Being dimensionless, its unit is 1; it is expressed as a number, e.g., 0.18. It is the same concept as volume percent (vol%) except that the latter is expressed with ...

  5. NACA airfoil - Wikipedia

    en.wikipedia.org/wiki/NACA_airfoil

    A: blue line = chord, green line = camber mean-line, B: leading-edge radius, C: xy coordinates for the profile geometry (chord = x axis; y axis line on that leading edge) The NACA airfoil series is a set of standardized airfoil shapes developed by this agency, which became widely used in the design of aircraft wings.

  6. Darcy–Weisbach equation - Wikipedia

    en.wikipedia.org/wiki/Darcy–Weisbach_equation

    Most charts or tables indicate the type of friction factor, or at least provide the formula for the friction factor with laminar flow. If the formula for laminar flow is f = ⁠ 16 / Re ⁠, it is the Fanning factor f, and if the formula for laminar flow is f D = ⁠ 64 / Re ⁠, it is the Darcy–Weisbach factor f D.

  7. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million ( ppm ...

  8. Pythagorean expectation - Wikipedia

    en.wikipedia.org/wiki/Pythagorean_expectation

    Initially the correlation between the formula and actual winning percentage was simply an experimental observation. In 2003, Hein Hundal provided an inexact derivation of the formula and showed that the Pythagorean exponent was approximately 2/(σ √ π) where σ was the standard deviation of runs scored by all teams divided by the average number of runs scored. [8]

  9. Coefficient of restitution - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_restitution

    At slower velocities the COR is higher than the above equation predicts, theoretically reaching e=1 when the above fraction is less than m/s. It gives the following theoretical coefficient of restitution for solid spheres dropped 1 meter (v = 4.5 m/s). Values greater than 1 indicate that the equation has errors.