Dielectric dispersion measurements of salt-water-saturated porous glass

Abstract

Porous-glass specimens with different porosities were made from glass spheres of diameter 0.2--0.3 mm. The cylinder-shaped specimens were filled with salt water with resistivity varying between 0.1 and 500 \ensuremath{\Omega}m, and the two-terminal admittance of these specimens was measured in the frequency range 5 Hz to 13 MHz. The dielectric constant and conductivity of a specimen as functions of frequency, with water resistivity as parameter, were both reduced to one single curve when plotted as a function of reduced frequency \ensuremath{\omega}/${\ensuremath{\omega}}_{0}$, where ${\ensuremath{\omega}}_{0}$ is the relaxation frequency of the fluid. The highest relaxation frequency of the specimens was measured to be ${\ensuremath{\omega}}_{0}$. The Lysne-Bergman relaxation-frequency density spectrum of the specimens can be given by g(${s}_{n}$) =${\mathrm{Cs}}_{n}^{\mathrm{\ensuremath{-}}b}$${\mathrm{exp}\mathrm{{}\mathrm{\ensuremath{-}}[\mathrm{log}}_{10}$/B (${s}_{n}$/D${)]}^{4}$}+${F}_{1}$\ensuremath{\delta}(${s}_{n}$-1), where ${s}_{n}$ is the relaxation frequency, b=0.84\ifmmode\pm\else\textpm\fi{}0.04, while C, D, and ${F}_{1}$ are porosity dependent.