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This thesis describes a study of electrical conduction in polyvinylchloride compounds. By way of an introduction the first chapter outlines mechanism of absorption and conduction in polymeric systems, reviews the principles of formulation of polyvinylchloride compiounds for use in electrical insulation applications, and gives a review of previous measurements on such compounds. In the second chapter a description of the experimental techniques employed in the present study is given. The experimental results are presented in the third chapter, and in the final chapter the results are discussed and conclusions drawn. The research described is the original work of the author and has not been submitted for any other degree. Additional information has been gathered from various literary sources which are listed at the end of the thesis.

The thermal conductivity of thin Germanane (GeH) layers was measured using suspended micro-devices with integrated heaters and thermometers. The thermal contact resistance of the GeH samples suspended on the measurement devices was determined from the measured thermal resistance values of samples with different suspended lengths. The room-temperature thermal conductivity of the GeH samples was observed to be 0.6-1.0 Wm⁻¹K⁻¹. This low thermal conductivity is attributed to phonon scattering by defects and grain boundaries in the layered materials, including scattering caused by gangling bonds associated with missing Hydrogen atoms between adjacent layers. / text

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In recent years, several attempts have been made to develop instrumentation to aid in the measurement of soil water electrical conductivity. Each of the instruments have specific limitations. This dissertation discusses the available methods of measuring this parameter and indicates the limitations of the transducers which have been described in the literature. Also, discussed are the basic theories of operation of these transducers and definitions related to soil salinity in general. The major objective of this research was to develop a new transducer which would be a significant improvement over existing types of instrumentation. It is believed that this research has led to the development of two transducers of different geometries which can assess the soil water conductivity over a wider range of matric potential just as rapidly and accurately as the next best unit. At the same time the new transducers incorporate automatic temperature compensation which has not been done by any other field instrumentation of its type. Also presented, is the application of heat transfer theories to the diffusion of ions from the transducer to the surrounding environment, Application of this theory allows one to predict how the transducer will respond to a step change in ion concentration in an unsaturated soil system where the only process involved is diffusion. Good agreement between experimental measurements and predicted response indicates that the model may also be useful in further refinements of the transducer.

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