Savart plate interferometry for isothermal diffusion measurements.
Savart plate wavefront shearing interferometry has been applied to make accurate determinations of diffusivity in an electrolyte (KCl) solution, at low concentrations generally considered inaccessible to optical measurement. The necessary improvement in sensitivity is achieved by operating at high shear and using appropriate methods of analyzing the interferograms. The technique is equally applicable to dilute nonelectrolytes. Hydrodynamic stability of the diffusion column, rather than the sensitivity of the interferometer, is probably the ultimate limitation on the capability of the method as concentration is progressively decreased.
Becsey
J G
JG
Aerospace Research Laboratories, Wright-Patterson Air Force Base, Ohio 45433.
Bierlein
J A
JA