A statistical definition of perfect mixtures of solids of different sizes
"When mixing solids, it is desirable to be able to evaluate the performance of a mixer in terms of its ability to produce mixtures that approach the theoretical limit of uniformity. Although a satisfactory correlation exists for mixtures where the particles are of uniform size, none has yet been developed for multisized particles. A mathematical definition of a perfect mixture of three sizes of particles is proposed. The principles employed can be extended to any number of sizes, but the complexity of the equations increases rapidly. Agreement with experimental results appears substantially better than that obtained by previous investigators."--Page 105.