-r_A rate of reaction, is defined as the number of moles of chloral reacting (disappearing) per unit time per unit volume (mol/dm3.s ).

Roughness for materials are determined by experiments. Absolute roughness for some common materials is represented on this data-set.

The  Adiabatic Bulk Modulus calculator computes the bulk modulus as a function of the change in pressure and volume and the initial volume.  

ALPHA_ROMEO make of a car

The alveolar gas equation is usually used to calculate the partial pressure of oxygen in the alveoli:

A unit used to measure the wavelength of X-rays. Because it's easier to measure the ratio between two X-ray wavelengths than it is to measure the wavelengths themselves, the wavelengths are usually stated as multiples of a standard wavelength. The X unit and the angstrom star are the units used for this purpose. Å* was defined by J.A. Bearden in 1965 to provide a unit approximately equal to the angstrom (10-10 meter or 0.1 nanometer). Later measurements have shown that in fact A* is equal to approximately 1.000 0015 x 10^-10 meter or 100.000 15 picometers.

Area Thermal Expansion: When the temperature of a surface changed ΔT, the change of its area ΔA is very nearly proportional to its initial area multiplied by ΔT. The Area Expansion equation is:

The Arrhenius Equation calculator computes the chemical reaction rate (k) based on a collision rate (A), activation energy (Ea) and a temperature (T). 

this equation gives the graphical method of calculating the Arrhenius equation.if one looks at the Arrhenius equation carefully,one can notice that the natural logarithm form of the Arrhenius equation is in the form of y = mx + b. In other words, it is similar to the equation of a straight line.

Artin's Constant is given by 0.373955813619202288054728