Comparison of thermal insulation performance of fibrous materials for the advanced space suit.
The current multi-layer insulation used in the extravehicular mobility unit (EMU) will not be effective in the atmosphere of Mars due to the presence of interstitial gases. Alternative thermal insulation means have been subjected to preliminary evaluation by NASA to attempt to identify a material that will meet the target conductivity of 0.005 W/m-K. This study analyzes numerically the thermal conductivity performance for three of these candidate insulating fiber materials in terms of various denier (size), interstitial void fractions, interstitial void media, and orientations to the applied temperature gradient to evaluate their applicability for the new Mars suit insulation. The results demonstrate that the best conductive insulation is achieved for a high-void-fraction configuration with a grooved fiber cross section, aerogel void medium, and the fibers oriented normal to the heat flux vector. However, this configuration still exceeds the target thermal conductivity by a factor of 1.5.
Heat Transfer by Gas Conduction and Radiation in Fibrous Insulations

 Thermal conductivity measurements were made on samples of an experimental glass fibrous insulation ranging in density from 0.5 to 8.4 pcf. Tests were carried out at atmospheric pressure with four different gases in the insulation samples, and the thermal conductivity with air was studied over a pressure range of 1 micron to 760 mm of Hg. Gas conduction is the most important mechanism of heat transfer. A theory of gas conduction in fibrous insulations was developed, and agrees well with experimental results. Theoretical considerations of heat transfer by radiation were confirmed by the experimental thermal conductivity values at low pressures. Methods are discussed of producing considerable reduction in the thermal conductivity of fibrous insulations.
Modelling environmental impacts of marine finfish aquaculture
Summary Our understanding of the interactions between fish farms and the environment has reached the stage where it is reasonable to expect that quantitative estimates of the possible environmental consequences of aquaculture development can be provided for regulatory and mitigation purposes. This paper summarizes recent developments in this area and provides several case histories of areas where theoretical analyses appear to have direct practical relevance. Fish wastes