Percolation and order-disorder transition

An extension of the Bruggeman's dielectric law, known as effective mean-field approximation (EMA), permits the description of the percolation and its behaviour far from the threshold, using inclusions of different shapes. In this case, the critical concentration and the shape factors are linked. A reformulation of the EMA equation, using the phase diagrams formalism, allows to establish that the direct (WD) and inverse (WI) Wiener equations are a mathematical base for the EMA equation, and that there is a relation with the results of the percolation theory in lattices. (c) 2006 Published by Elsevier B.V.