Picketts equation

Pickett [45] modified the n-layer BET treatment to take into account the decrease in probability of escape from an elemental area covered with n layers as adjacent elements also become covered with n layers. This leads to the result that there can be no evaporation from such an area. With this assumption Pickett derived the equation  

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The dependence of gas adsorption on the pore structure of the sorbent has been extensively studied by Ozawa, Kusumi, and Ogino (34) and theoretically correlated by application of the Pickett equation. Data obtained from this study has been plotted... 

Equation (31) has also been used to correlate results obtained in annular channels with insufficient hydrodynamic entrance length (B2, B3). Some of the data fit Eq. (31) with a slightly smaller coefficient. A similar expression, including terms for the hydrodynamic entrance length, was used by Pickett and Ong (P3a). 

Modifications and Other Derivations of the B.E.T. Equation Cassie (21), and more recently Hill (22) have found that eq. (8), the B.E.T. equation, can also be derived by a statistical thermodynamic approach. Hill (23) has in addition pointed out that the original postulates of Brunauer, Emmett, and Teller (7) that lead to the derivation of eq. (9) by a kinetic method can be shown by statistical thermodynamics to lead to the same equation. This is of interest since both Pickett (24) and Andersoh (25) have suggested that the method of summation used in obtaining eq. (9) should be so altered as to produce an equation in the form... 

A general approach is described by Pickett a material balance for bubble formation similar to Eq. (5.11) is combined with the Bruggeman relationship to give the conductivity of gas-bearing electrolytes. Conductivity, which varies along the reactor, is combined with a voltage balance and the resulting systems of equation solved numerically in order to evaluate current distribution. 

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