A trend in the dielectric spectrum of a moist dispersed medium

Conclusions

• 1. It follows from (12) that ɛ for a heterogeneous system can be represented to a first approximation for frequencies greater than a certain limit as a linear function of the water content W; certain deviations from linearity can occur when the conditions for passing from (10) to (11) are violated, for instance when ɛ_wi≫-ɛ_wk, when α_i>α_k (the polarization of the free water is different from that of the bound water). In a soil, such deviations (Fig. 2) arise also from swelling, and hence deviation from (8).

• 2. Expression (12) has been derived by using Hippel's mixing formula and agrees with empirical relationship (1), which shows indirectly that it is in principle possible to use it to calculate the dielectric constant of such a system. However, it should be borne in mind that one needs to take into account not only the dielectric constants of the solid, liquid, and gaseous phases, but also the values for the transition phases, including the adsorption layer and the conducting inclusions, especially as these quantities vary with frequency.