Auger parameter, definition

While the Auger parameter can be expressed in several ways, one of the most commonly used definitions is that shown in Equation 1... 

Alloy-metal Auger parameter shifts were obtained from the measured Auger kinetic and photoelectron binding energies using the definition given by Williams and Lang [12] ... 

Actually, the wall shear stresses found in a cylindrical tube are not really material parameters at all, because their dependence on geometry limits their applicability to cylindrical-tube flow. For cylindrical tubes of similar geometry and a constant length/diameter ratio, the wall shear stresses determined according to equation 2 are identical. Other shapes, however, such as cones (die) or auger chaimels demand a different, more suitable approach, with equation 2 modified to accommodate the corresponding geometric boundary conditions. Nonetheless, the waU shear stress remains superior to the coefficient of friction as a useful material parameter, because it yields a correct, practical, near-system definition of a compound s material properties, as explained above. 

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