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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Utilization of Different Curing Systems and Natural Zeolite as Filler and Absorbent for Natural Rubber/Nitrile Rubber Blend) ผู้เขียน: ทัธชาวรรณ ศิริยงค์,  ดร.วิรัญญา แก้ววัฒนะ, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe effects of the vulcanization system and natural zeolite loading on the mechanical properties, thermal and oil resistances of a natural rubber (NR) and acrylonitrile-butadiene rubber, also known as nitrile rubber (NBR) blend in the ratio of 20:80 was studied. The vulcanization systems used in this study were conventional vulcanization (CV), effi cient vulcanization (EV) and peroxide vulcanization. The amount of natural zeolite fi lling added was varied from 0 to 60 parts per hundred (phr). The vulcanizates cured with the CV system gave the greatest tensile properties; however, they showed the lowest thermal and oil resistance. Greater thermal and oil resistance was observed in the vulcanizates cured with dicumyl peroxide (DCP). Moreover, the tensile strength and 100% modulus of the vulcanizates increased with an increase in the natural zeolite loading, while there was no substantial change in the compression set. The oil resistance in both diesel and biodiesel blends of the vulcanizates was signifi cantly improved with the natural zeolite content. The vulcanizates containing 40 phr of natural zeolite cured with peroxide showed the lowest swelling and the highest relative tensile strength in oil (diesel and biodiesel). As well as the oil resistance, the optimum mechanical properties were observed in the vulcanizates fi lled with 40 phr of natural zeolite and cured with peroxide. |
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หัวเรื่อง:ผลของสารดูดน้ำไวเทอร์ราต่อความเป็นประโยชน์ต่อพืชของน้ำในชุดดินกำแพงแสน ผู้เขียน:ดร.สุนทรี ยิ่งชัชวาลย์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractWater – absorbent agent ‘Viterra’ was mixed with Kamphaeng Saen soil series (Typic Haplustalfs) at 4 rates of 0, 1, 3 and 5 g/l of air – dried soil to study its beneficial effect on the water availability of soil. The soil under study was prepared in two prepared in two ways. The original soil and the potting mixture of soil with duck manure, sand and rice hull for vegetable seedling culture. Only Viterra at the rate of 3 g/l and higher had the effect on soil water availability. At saturation, mixing Viterra at the rate of 5 g/l increased the saturation water content (mass basis) by 26.9% in the original soil and 38.1% in the potting soil, Upon wetting, the bulk volume of the soil also expanded. However, the available water capacity was increased by Viterra only in the original soil. This was the result of an increase in pore volume of 10-60 micrometer size. Not only the available water capacity but also the specific water capacity was greatly improved by the addition of Viterra to the original soil. Potting soil, on the other hand, showed no increase in available water capacity since addition of Viterra increased mainly the volume fraction of the large drainage pore size of > 60 micrometer. Therefore, the water-absorbent agent increased the soil water content at saturation and increased the volume, but the effect on the availability of the water depended on the soils. When mixed with soil which had a greater volume of large-size pores, such as potting soil. Viterra seemed to be able to absorb a much greater amount of water and then expanded fully. This led to an increase in the volume fraction of large-size pores in the soil. In a denser soil, on the other hand the volume expansion of Viterra may be less. So the increase in pore volume of the soil was that of the medium- size pores. This was more desirable as the medium –size pores contained water available to plant. |