Diffusion coefficients impedance factor

Olesen T, Moldrup P, Yamaguchi T, Rolston DE. 2001. Constant slope impedance factor model for predicting the solute diffusion coefficient in unsaturated soil. Soil Science 166 89-96. 

Staunton S. 1990. A comparison of the surface impedance factors of Ca, Na, Rb and Cs derived from their self-diffusion coefficients in various soils. Journal of Soil Science 41 643-653. 

If substance B is a porous solid the molecular diffusion coefficient D has to be replaced by the effective diffusion coefficient DeB. This is smaller than the molecular diffusion coefficient because the movement of the molecules is impeded by the pores. It is common practice to define a diffusion resistance factor... 

There are factors that we have not considered. The surface of a protein molecule generally comprises polar side chains that interact strongly with solvent molecules and ions. These interactions impede its mobility. Furthermore, we have neglected to take into account the anisotropy of reactivity that we outlined above. Diffusion to the electrode surface must be coupled to corrective rotational motion either on approach or as a rolling movement during encounter, otherwise contact may be restricted to an inactive area of protein surface. The question arises, What is meant by a diffusion coefficient . The value which is relevant to a voltammetric experiment, in which there is a dependence upon molecular orientation, must be lower than the value which is determined by a technique like ultrafiltration. The picture afforded by Fig. 2 is thus optimistic in that it compares the maximum faradaic responses that may be achieved. 

Effective cathode gas diffusivity Effective anode gas diffusivity Volume fraction porosity Surface exchange coefficient Impedance at angular frequency Imaginary part of admittance Real part of admittance Anode thickness Cathode thickness Electrolyte thickness Exchange current density Anode limiting current density Cathode limiting current density Three phase boundary length Transfer coefficient of symmetry factor... 

---