This research aims to develop the concrete blocks mixed with cassava pit waste. There are 6 mixing ratios among Portland cement type1: rice hush ash: quarry dust: cassava pit waste: water reducer type A: tap water that include 0.7: 0.3: 10: 0: 0.02: 0.6 0.7: 0.3: 9.9: 0.1: 0.02: 0.6 0.7: 0.3: 9.7: 0.3: 0.02: 0.6 0.7: 0.3: 9.4: 0.6: 0.02: 0.6 0.7: 0.3: 9.1: 0.9: 0.02: 0.6 and 0.7: 0.3: 8.8: 1.2: 0.02: 0.6 by weight. The concrete block samples were casted same as the ordinary concrete blocks and test were conducted according to TIS.57-1990 standard. From the results the best proportion of concrete block mixed with coconut shell ash is 0.7: 0.3: 9.7: 0.3: 0.02: 0.6. The proper ratios of cassava pit waste can decrease the density or weight and increase the thermal insulation of concrete blocks. However the over amounts of cassava pit waste that effected to increase the water absorption and decrease the compressive strength properties of concrete blocks.

Silica is an amorphous and nanometer scale voids and porous form of silicon dioxide. As long known for its high specific surface area synthetic silica has been used to adsorb water readily and applied for keeping many biological products dry protecting equipment from moisture damage. In the study the researchers have interested in making the tentative eco-friendly dehumidifying products based on the silica extract from bamboo leaves. The extraction procedures were performed by boiling dry bamboo leaves with various concentrated hydrochloric acid (HCl) at 1 2 3 and 4 M then burning them at 650oC for 4 hr before analyzing the purity of the biosilica with the X-ray Fluorescence Method. The results showed that the highest purity of the biosilica sample at 96% could be obtained after treated with 4 M HCl comparing with the control commercial silica. By hygroscopic test the extracted biosilica with 2 M HCl showed the highest moisture absorption properties close to the commercial silica. While the highest adsorption capacity was found in the biosilica sample treated with 3 M HCl. The dehumidifying efficiencies of all HCl treated biosilica power were not much different comparing to the commercial silica gel. Instead of using synthetic silica therefore this high environmentally friendly and cheaper biosilica from bamboo leaves can preferably be decent and further applied in green industry.

This research work was to study the effect of moisture on mechanical properties of wood/polyvinylchloride composites (WPVC). WPVC specimens in ratio of PVC and wood (100:100 by weight) were prepared by using twin screw extruder. The water conditions for WPVC specimen immersion testing were varied for temperatures of 30-70 oC and specimen immersion time of 0-120 h. The moisture effect was investigated by measuring flexural properties and hardness of WPVC as comparing with case of PVC specimen. The result suggested that flexural modulus of WPVC tended to decrease with increasing time of water immersion and then remained unchanged at immersion time of more than 72 and 48 h for water temperature of 30 and 70 oC respectively. The decrease rate in flexural modulus enhanced when water temperature increased. Flexural modulus of PVC slightly changed with increasing both immersion time and water temperature. Flexural strength for both PVC and WPVC specimens were found the change at water temperature of 70 oC only. Flexural strength of PVC tended to slightly increase with increasing immersion time whereas flexural strength of WPVC slightly decreased with increasing immersion time. Hardness of PVC specimen in cases of both water temperature of 30 and 70 oC slightly increased with increasing immersion time. For WPVC hardness tended to decrease with increasing immersion time and water temperature.

This research objective was to determine physical and aerodynamics properties of Khao Dawk Mali 105 paddy (Thai Jasmine paddy rice). The paddy sample in this test was prepared with different moisture contents in the range of 10-26%WB and air temperature in aerodynamics properties test was varied in the range of 50–100 OC. Test results were analyzed to determine the statistical mean difference by DMRT method (at P<0.05). It found that moisture content in paddy affects the difference of average length width and thickness of grain and results the difference of geometric mean diameter and degree of sphericity of paddy. An increase in paddy moisture results the increase of average bulk density and kernel density but it reduces the porosity of paddy. Moisture content in paddy affects the difference of terminal velocity. Moisture content in paddy and air temperature influenced the difference of average drag coefficient of paddy.

Defrosting at evaporator panel is one of working cycles in freezer. Power consumption in defrosting does not meet the objective of using freezer therefore the approach to decrease power consumption in defrosting is one strategy for energy saving. Normally the cycle of defrosting in freezer is a constant time that specify by referring to the highest humidity period. With this control concept the problem of temperature exchange is not occurred from ice accumulation at evaporator panel but it makes the over necessity of defrosting process in the low humidity season and cause the unnecessary power usage in freezer. This thesis presents the control approach for defrosting by using the difference of the temperature at evaporator and the temperature at chilling area. By using this approach the defrosting process is operated depend on load and the fan is on or off relate to defrosting time. Test results demonstrate that about 12% of power can be saved by this control approach when compared to constant time control.