9612044 This work is an investigation of non-Fourier conduction in heterogeneous media. The possibility of the existence of thermal waves with relatively long relaxation times will be explored. The wave-like behavior may arise from the contact resistance and the differing thermal masses of the material constituents. Theoretical models will be used to identify characteristics of the microstructure likely to enhance or inhibit wave behavior. These models will be validated against experiments to systematically demonstrate the expected phenomena. Materials to be explored include porous media, composite media, food products, powders, and biological materials. Applications are expected in tumor and cell destruction, freezing and cryopreservation of biological materials, freeze-drying technology and the setting of adhesives.