Thermal Conductivity and Diffusivity
The chapter is concerned with new developments over the last two decades of familiar experimental techniques for the measurment of thermal conductivity and related transport properties, as well as a variety of diffusion coefficients. It begins with an historical review of the transient hot-wire instrument for accurate thermal conductivity measurement; it has widespread applicability over a wide range of thermodynamic states and a variety of materials. The second section explores a family of measurement techniques that exploit the disturbance of materials caused by absorbtion of light in photoacoustic and photothermal techniques to study thermal transport processes. In Section 5.3, solutions of the diffusive transport equations in simple geometries are derived and simplified to offer new methods for the study of thermal and mass transport in materials of industrial importance. Finally, in Section 5.4, recent work to develop established experimental techniques for the study of both mutual and self-diffusion coefficients in extremes circumstances, such as high pressures and/or high temperatures and special thermodynamic states, are considered.