  Clausius-Mossotti approximation is extended to describe the measured magnetic
moment of an ellipsoidal sample containing magnetic or nonmagnetic ellipsoidal
inclusions and magnetic or nonmagnetic matrix. The magnetic field in the matrix
and inclusions is calculated. The magnetic energy of a system is calculated
also. The equilibrium shape of a pore in a ferromagnetic sample is
investigated. The phenomenon of cavitation in porous ferromagnetic samples is
described. The model is applied to calculate magnetic properties of granular
superconductors. The effective electric conductivity of a sample of a composite
material, containing an arbitrary number of differently ordered distributions
of ellipsoidal inclusions is calculated. Effective conductivity of a composite
material, consisting of fibers of high conductivity and a matrix of low
conductivity is discussed. Concentrated electric field in the vicinity of the
ends of a conductive nanofiber in a composite material is calculated. The high
quantity of this field is of an extreme importance to provide the proper
functioning of monitors, based on conductive nanofibers in dielectric media.
