Diffusion in Gases and Porous Media

The world we live in exhibits, on different scales, many phenomena related to the diffusion of gases. Among them are the movement of gases in earth strata, the aeration of soils, the drying of certain materials, some catalytic reactions, purification by adsorption, isotope separation, column chro­ matography, cooling of nuclear reactors, and the permeability of various packing materials. The evolu...