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 $$ \Delta v $$ 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:

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

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