The general theory of the transient plane source (TPS) technique is outlined in some details with approximations for the two experimental arrangements that may be referred to as ‘‘hot square’’ and ‘‘hot disk.’’ Experimental arrangements and measurements on two materials, Cecorite 130P and Corning 9606 Pyroceram, using a hot disk configuration, are reported and assessed.

Transient measurements of thermal conductivity, thermal diffusivity, and specific heat capacity have been performed with hot disk sensors in thin samples of metallic materials. With this new variation of the hot disk method the sample size can be reduced to a volume less than ten cubic centimeters for copper at room temperature. It is also shown that the specific heat capacity can be conveniently measured in transient recordings of slightly longer duration. On comparing with standard values the accuracy turns out to be better than 1% while the precision (standard deviation of the mean from six measurements) on the average is about 0.5% for all values recorded.

A transient hot-strip method has been developed for use with solids and fluids with low electrical conductivity. The hot strip (thin metal foil) is used both as a constant plane heat source and a sensor of the temperature increase. The accuracy of the method is so good that it might even be used for the measurement of the specific heat especially under difficult experimental conditions when the standard methods cannot be used or would be very inconvenient. This method has been tested in measurements on fused quartz, glycerine and Araldite at room temperature. The experimental conditions that cause deviations from the mathematical solution of the thermal conductivity equation are discussed and estimates for their maximum influence on the measured quantities are given.

The electrical circuit for the recently developed transient plane source (TPS) technique for fast and precise measurements of thermal tramport properties of solids has been modified for more convenient 8nd more automated measurements. The technique has been tested for measurements of thermal conductivity and thermal diffusivity for a series of building materials ranging from thermally insulating materials (extruded polystyrene and PMMA) to good thermal conductors (stainless steel and aluminium). The results obtained in this work agree well with other techniques and international standrrrd materials This agreement indicates that the TPS method is accurate to within f 5% over a thermal conductivity range of four orders of magnitude (0.02 W m K to 2QO W m K I).

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The self-diffusion of a particle on a flexible surface, such as a fluid bilayer membrane or a macroscopic interface, is analyzed theoretically in order to relate the macroscopic diffusion coefficient DM, describing displacements in a laboratory-fixed plane, to the intrinsic surface diffusion coefficient DS and to the configurational statistics of the surface. An exact result for DM is obtained for a rapidly fluctuating surface. For a static surface, rigorous bounds on DM are established and an effective medium approximation is derived that should remain accurate for strongly disordered surfaces. With the aid of these results, classical self-diffusion measurements can be used to study the configuration, bending rigidity, and interactions of flexible membranes and interfaces.

The objective of this work is to improve measurements of transport properties using the hot disk thermal constants analyzer. The principle of this method is based on the transient heating of a plane double spiral sandwiched between two pieces of the investigated material. From the temperature increase of the heat source, it is possible to derive both the thermal conductivity and the thermal diffusivity from one single transient recording, provided the total time of the measurement is chosen within a correct time window defined by the theory and the experimental situation. Based on a theory of sensitivity coefficients, it is demonstrated how the experimental time window should be selected under different experimental situations. In addition to the theoretical work, measurements on two different materials: poly͑methylmethacrylate͒ and Stainless Steel A 310, with thermal conductivity of 0.2 and 14 W/mK, respectively, have been performed and analyzed based on the developed theory.