Some Mechanisms for the Process of Flow

In 1935, Ham (77) proposed a specific equation for the rate of flow of gas through a metal based upon kinetic theorj. Ham s equation approximates to dp dt 

Riemann(78) has suggested another variant of Richardson s equation based upon thermodynamic considerations and Tick s law. His equation took the form 

In this equation a = G jR (C denotes the atomic heat of dissolved gas atoms), = pressures of gas at the ingoing and outgoing surfaces respectively of a plate of thickness Z, and AHq is defined by AH = + (f — 2a) RT AH denotes 

Rate = blether processes may be conceived, but they are not probable ones, and in any case the six listed above are adequate for this discussion. Smithells and Ransley, considering the first four of the preceding rate equations, deduced as a general expression for the velocity of permeation 

Wang (80) and Barrer(8i) gave equations defining the permeation velocity which included all six of the processes above. 

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