Basic Research on the Characteristics of Cloths to Keep Warmth and Moisture Permeability

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Experiments and analyses were done concerning the measurement of thermophysical properties of a textile fabrics, which were necessary for the basic discussions of the characteristics of cloths, such as keeping warmth and moisture permeability. Concerning a textile fabrics, the real thermal conductivity in a vacuum, the permeability, the porosity and the apparent thickness were measured precisely. On the bases of the above properties, the physical meaning of the thermal transmittance of the textile fabrics determined by the ASTM standard were discussed. Then, the possibility and the directions to improve the ASTM standard were suggested.The following results were obtained in the financial year 1991.1. On the bases of the transient flat-plate measuring method by O. Krischer, the apparatus to measure simultaneously the thermal penetration factor, the specific heat and the thermal conductivity of a textile fabrics both in a vacuum and in an air was constructed. And the measurements were done using the standard textile sample made of polyester.2. An apparatus to measure precisely the permeability of a textile sample was proposed and constructed under the measuring condition of low stable fluid velocity, where the Darcy's law can be applied. Measurements were done using the standard textile sample.3. An apparatus to measure the thermal transmittance was prepared on the instructions of the ASTM standard test method, and the measurements were done on the above textile sample. It was pointed out, as the problems of the test method, that the control of the guard heater to ensure the amount of heat supplied to the sample was impossibly difficult and that the modification of the natural convection effects over the textile sample was not adequate.In the financial year 1992, the results obtained through the former year were discussed precisely and the contents were filled up.