This work examines the foam density, average cell sizes, and cell structure of four polystyrene (PS) blended with calcium carbonate (CaCO 3 ) or low density polyethylene (LDPE) at various ratios. The PS/CaCO 3 and PS/LDPE are foamed by carbon dioxide (CO 2 ) under supercritical conditions. CaCO 3 and LDPE can strongly influence the foam density, average cell sizes, and cell structure of PS foams. Based on the result of PS/CaCO 3 foams and PS/LDPE foams, the thermal conductivity of large porous PS foams as core materials used in vacuum insulation panels (VIPs) is further studied. Large porous PS foams are produced by the mixture of CO 2 and fluorocarbon or the mixture of CO 2 and nitrogen (N 2 ) as foaming agents. The content of open-cells in PS foams is affected by materials, foaming temperatures, and foaming agents. A higher content of open-cells in a porous PS foam can lead to a lower and more stable thermal conductivity of VIPs.
This work examines the foam density of polystyrene (PS) blended with low density polyethylene (LDPE) at various ratios, and the thermal conductivity of vacuum insulation panels (VIPs) using PS/PE with filler foam as core materials. The experimental results indicate that LDPE strongly influences the foam density of PS/PE foam and the content of open-cells in PS/PE with filler foam. A higher content of open-cells in PS/PE with filler foam can lead to a lower thermal conductivity of VIP.
This work examines four polystyrene (PS) resins and PS resins with fillers. The materials are processed into sheets and then the sheets are foamed at various supercritical conditions. The morphology of the foam is studied and a large porous PS foam is also developed for a vacuum insulation panel.
Orientation mapping based on electron backscatter diffraction (EBSD) technique is applied to reveal microstructural and textural characteristics of flip chip bonded Au at its different processing stages. Attention is paid also to the influence of thermosonic energy. It is found that columnar grains in free air ball (FAB) that inherit the orientations of heat affected zone (HAZ) and layer formed grains are formed at first bonding interface owing to the thermosonic vibration. Recrystallised grains are occasionally detected between the heavily strained boundary region and the less strained centre region.
Adsorption dehumidification and drying equipment is essential general equipment for domestic and industrial use. The most commonly used type in industry is the compressed air adsorption dryer. The analysis results show that the heat loss of the traditional heat air regeneration system of the compressor dryer is 39.4%, and the exhaust waste heat is 32.4%. The actual use of heat energy for desiccant regeneration is only 28.2%. Therefore, this study uses an innovative electrothermal adsorbent unit (ETAU) to regenerate the desiccant. By directly heating the adsorbent, heat loss can be effectively improved. On the other hand, the composite arrangement of zeolite and activated alumina is used. The inlet compressed air is firstly treated by the activated alumina, which has a high adsorption capacity in the high relative humidity condition, then a zeolite is used as a second part to make the dew point reach –40 °C. In the regeneration step, the airflow direction is reversed, whereby the zeolite is regenerated by the ETAU, and the waste heat of the exhaust air is used to regenerate the activated alumina, which reduces the temperature of the exhaust air. Compared with the traditional heat air compressed air system, the two technologies can save about 27% energy in total.
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