GEOMETRY AND TOPOLOGY OF POROUS MATERIALS.

Porous materials are heterogeneous two-phase systems. One phase is solid and one phase fluid or empty. Both phases must be at least in part macroscopically continuous. The skeletization procedure of C. Lin and M. H. Cohen elucidates simply but precisely the principal topological and geometric features of porous materials, providing rigorous definition of the familiar concepts of chambers, channels, and throats in the pore space. The power and utility of their method was well illustrated through an analysis of the morphologies of sedimentary rocks. There were six common morphological features of sedimentary rocks which were truly astonishing in the light of their thermal history and in relation to our experience with the sintering of granular materials. The key feature from which the others follow was the persistence of small intergranular contacts. A reversal for sedimentary rocks of the interfacial energy relations holding for sintering then immediately explains all of the morphological features, including, under appropriate circumstances, the fractal character of the pore space.