The Wagner-Maxwell model for dilute suspensions

Since there is no free charge at the interfaces S, the dielectric displacement D should not change through the interface boundary 

The solution of Laplace s equation under the boundary conditions expressed in Eq.(126) and (127) is presented [69] as  

Suppose that in a volume V the number of small particles dispersed in is N and there is no interaction between particles, then the total dipole moment in this volume V is  

If the volume V is assumed as a big particle of radius b and of dielectric constant e, then according to Eq.(130), the total dipole moment D,o,ai can be expressed in a different way as  

Where (() is the particle volume fraction, Eq.(133) can be rewritten as in a more complex form  

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