The formation factor of the pore space of binary mixtures of spheres

Abstract
The authors have measured the conductivity of models of porous media made of binary mixtures of insulating spheres, the pore spaces of which are filled with conducting fluid. Although the sphere diameter ratios used in the experiments, 4 and 11, lead to packings with very different geometrical structures, the experimental points can all be fitted using Archie's law with an exponent m=1.46. They find just a small difference between the conductivities of the two types of packings.
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