Dielectric, ultrasonic and ' 3C nuclear magnetic resonance relaxation measurements are reported on mixtures of t-butyl alcohol and water over the temperature range 27S308 K. Supporting measurements of the refractive index, density and viscosity are also presented. Deviations from ideal mixing behaviour are observed in the volumes of mixing, permittivities and adiabatic compressibilities of the mixtures. The location of the minima in the excess occurring at different compositions depend upon the method of measurement. Similarly the relaxation behaviour, as observed using different techniques, reveals different aspects of the motion of the molecules in the fluid. The various effects observed are rationalized in terms of a model in which it is assumed that t-butyl alcohol dimers and trimers and various hydrated forms play an important role in determining the structure of these mixtures.

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A mathematical form is proposed for the study of the problem of reflection-transmission of monochromatic ultrasonic plane waves at the interface between two arbitrary anisotropic semiinfinite media. The method used leads to a complete determination of all characteristics of the studied waves for all possible configurations, i.e., their directions of propagation, polarizations, and magnitudes. In particular, cases are taken into account where the waves generated by the existence of the interface are evanescent or more generally inhomogeneous. Applying this method to the calculation of several practical cases typically encountered in ultrasonic nondestructive evaluation fields, this paper points out the existence of phenomena that cannot be interpreted by classical methods usually used for the resolution of this kind of problem.