Strange–Rahman–Smith equation

The Strange–Rahman–Smith equation is used in the cryoporometry method of measuring porosity. NMR cryoporometry is a recent technique for measuring total porosity and pore size distributions. NMRC is based on two equations: the Gibbs–Thomson equation, which maps the melting point depression to pore size, and the Strange–Rahman–Smith equation, which maps the melted signal amplitude at a particular temperature to pore volume.

Equation

If the pores of the porous material are filled with a liquid, then the incremental volume of the pores $\mathrm{\Delta }v$ with pore diameter between $x$ and $x+\mathrm{\Delta }x$ may be obtained from the increase in melted liquid volume for an increase of temperature between $T$ and $T+\mathrm{\Delta }T$ by:

$\frac{dv}{dx}=\frac{dv}{dT}\frac{k_{GT}}{x^2}$

Where: $k_{GT}$ is the Gibbs–Thomson coefficient for the liquid in the pores.