Yttria stabilized zirconia (YSZ) has been studied as a candidate reference material for thermophysical properties. In this study, the high-temperature stability of thermal diffusivity has been evaluated using Referceram ZR1 which was originally developed as a reference material for mechanical testing of fine ceramics. Thermal diffusivity of specimens before and after heat-treatment at various temperatures between 200 and 1500°C in air were measured by laser flash method. The heat-treatment at 900°C effected little change in thermal diffusivity. However, after heat-treatment at 1000°C or above, thermal diffusivity values were effected by phase separation, phase transportation, crack occurred in grain boundary, and so on. Therefore ZR1 should be used as a thermophysical reference material at temperatures below 900°C.
High pressure density behaviors for fluid mixtures made of carbon dioxide with ethyl acetate, 1–propanol, 2–propanol, or methanol at 313.15 K were satisfactorily correlated. The standard deviation was between 0.12 and 0.30kg·m-3 in density for each system.
The quantitative structure-activity relationships (QSAR) correlations were developed for the aqueous solubility of organic compounds at 298.15, 473.15, and 573.15 K. To elucidate the molecular structural variables to control the solvation phenomena, we firstly developed the QSAR correlation of solubility of 108 organic molecules in water at 298.15 K with the use of experimentally and theoretically derivable variables. The experimental variable used was the octanol-water partition coefficient and melting point, while the theoretical variables were LUMO energy and total molecular surface area, which were determined with the COSMO-PM3 method. Based on the results at 298.15 K, the QSAR correlations for aqueous solubility at 473.15 K and 573.15 K were determined with the use of the literature solubility data for 21 compounds at these two high temperatures. It was found that the QSAR correlation with COSMO-PM3 method is able to predict the aqueous solubility of organic compounds at 473.15 and 573.15 K from the molecular structural properties and the melting temperature, since the octanol-water partition coefficient can be predicted from atom/fragment contribution method.
Thermal conductivity of the surface layer of engineering materials changes apparently at the early stage of degradation because of many micro-cracks. A new method to evaluate and diagnose the degree of degradation of materials from the change of thermal conductivity is proposed. It is theoretically discussed that the existence of the micro-crack layer influences on temperature responses measured by a thermophysical handy tester. By definition of a thermal degradation parameter, the deteriorative stage of materials can be evaluated. In order to verify this theory, fatigue tests using metallic materials are conduced, and comparative studies between before and after fatigue test are made. A correlation between the existence of micro-crack and the decrease of thermal conductivity can be obtained by them. As a result, it is ascertained that the thermal degradation parameter can be easily estimated from the temperature response curve obtained by the tester.
The accumulation of experimental fluid thermophysical properties in a wide temperature and pressure ranges has been desired according to the latest progress in engineering technology. Development of remote control system for fluid thermophysical property measurements has been undertaken with the aim of the efficient data accumulation by automatic measurements. Effectiveness of the present automatic operating system has been confirmed by a preliminary measurement of liquid thermal conductivity based on the transient hot-wire method.
A simple method for viscosity measurements of Newtonian liquid by using temperature difference between the mean surface of a uniformly heated vertical plate and the ambient liquid formed by natural convection has been proposed. The measuring system is simply composed of a beaker contained with tested liquid, a vertical heated plate, thermocouples for the heated surface and the ambient liquid, a power supply, a voltmeter, a recorder and a personal computer. From comparison of the measured results on pure water and silicone oil with known thermophysical properties, a fairly good agreement has been obtained, and the validity of the present method has been confirmed.