“…These techniques range from the simplistic, such as crushing, imbibition, and microscopy (optical or electron), to the most complex Small-Angle Neutron Scattering (SANS) measurements requiring the use of a particle accelerator or nuclear reactor. Pore size distributions can be obtained using gas adsorption (usually with nitrogen) (Brunauer et al, 1938;Barrett et al, 1951), Differential Scanning Calorimetry (DSC) thermoporosimetry (Brun et al, 1977), Mercury Intrusion Porosimetry (MIP) (Ritter and Drake, 1945), SANS (Feigin and Svergun, 1987), and various Nuclear Magnetic Resonance (NMR) techniques (Watson and Chang, 1997;Barrie, 2000). Some of these methods, notably gas adsorption, DSC thermoporosimetry, and most NMR measurements, probe the surface-to-volume (S/V ) ratio of the pore structure and assumptions have to be made about the pore geometry to derive a characteristic length scale (radius or diameter) for the porous matrix.…”