Voids most-open packing

Porosity is one of the most important continuum-scale parameters. It is defined as the fraction of the total volume that comprises void space e = Woid/ ktotai-Equivalently, the solid volume fraction ((f) = 1 - e) is generally used for fibrous materials or other open structures. The term microporosity implies that the particles in a porous medium are themselves porous, usually at a much smaller scale. A common example is porous catalyst in a packed-bed reactor. 

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