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, that maps the melting point depression to pore size, and the Strange–Rahman–Smith equation that 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 $\Delta v$ with pore diameter between $x$ and $x+\Delta \,x$ may be obtained from the increase in melted liquid volume for an increase of temperature between $T$ and $T+\Delta T$ by:

${\frac {dv}{dx}}={\frac {dv\,k_{GT}}{d\,T\,x^{2}}}$

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