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For a prospective solution of effective recycling of gypsum board wastes, the present study was conducted to evaluate applicability of reclaimed gypsum as stabilizing agent for improvement of soft clayey ground. A series of unconfined compression tests and needle penetration tests were conducted to understand the fundamental properties of reclaimed gypsum and gypsum treated soils and the durability in water. An important finding was strength decrease in relation to mixing time of gypsum and soil. This may attribute to excessive mixing that caused breakage of the promptly hardened gypsum treated clay. In addition, from sounding and laboratory tests on the stabilized ground by shallow mixing method with different execution conditions, it was found that the strength of stabilized ground appeared in an early stage and that the hardening effect of cement that was used in combination with gypsum continued in a longer period. Regarding an environmental aspect, a specific amount of cement could have restrained leaching fluorine satisfactorily under the standard level in the field by adopting suitable mixing proportions based on the laboratory mixing test results. For practical application, the mixing procedure was a major factor of strength growth when hemihydrate gypsum was used to stabilize soft clayey ground. 相似文献
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Mohamed Ismael Riadh Sahnoun Ai Suzuki Michihisa Koyama Hideyuki Tsuboi Nozomu Hatakeyama Akira Endou Hiromitsu Takaba Momoji Kubo Shinkichi Shimizu Carlos A. Del Carpio Akira Miyamoto 《International Journal of Greenhouse Gas Control》2009,3(5):612-616
DFT calculations in gas and aqueous solution phases have been performed to study the mechanism of carbamate formation by the absorption of CO2 in 2-amino-2-methyl-1-propanol (AMP). The results reveal the importance of considering the effect of water as solvent for the reaction to proceed. Furthermore water molecules play an important role as a basic reactant leading to stable intermediates formation. These results point at a single-step, third order reaction as the most probable mechanism for the formation of carbamate by the absorption process. 相似文献
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Rumana Tasmin Yohei Shimasaki Michito Tsuyama Xuchun Qiu Fatma Khalil Nozomu Okino Naotaka Yamada Shinji Fukuda Ik-Joon Kang Yuji Oshima 《Environmental science and pollution research international》2014,21(2):1064-1070
In the actual environment, temperatures fluctuate drastically through season or global warming and are thought to affects risk of pollutants for aquatic biota; however, there is no report about the effect of water temperature on toxicity of widely used herbicide diuron to fresh water microalgae. The present research investigated inhibitory effect of diuron on growth and photosynthetic activity of a green alga Pseudokirchneriella subcapitata at five different temperatures (10, 15, 20, 25, and 30 °C) for 144 h of exposure. As a result, effective diuron concentrations at which a 50 % decrease in algal growth occurred was increased with increasing water temperature ranging from 9.2 to 20.1 μg L–1 for 72 h and 9.4–28.5 μg L–1 for 144 h. The photochemical efficiency of photosystem II (F v/F m ratio) was significantly reduced at all temperatures by diuron exposure at 32 μg L–1 after 72 h. Inhibition rates was significantly increased with decreased water temperature (P?<?0.01). Intracellular H2O2 levels as an indicator of oxidative stress were also decreased with increasing temperature in both control and diuron treatment groups and were about 2.5 times higher in diuron treatment groups than that of controls (P?<?0.01). Our results suggest water temperatures may affect the toxicokinetics of diuron in freshwater and should therefore be considered in environmental risk assessment. 相似文献
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Wang Juntao Li Wenhua Nozomu Mishima Adachi Tsuyoshi 《Journal of Material Cycles and Waste Management》2021,23(5):1765-1776
Journal of Material Cycles and Waste Management - Different deposit–refund systems are being practically applied to promote the proper treatment of end-of-life products in China. One is... 相似文献
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Xuehao Zhao Yinhu Wu Xue Zhang Xin Tong Tong Yu Yunhong Wang Nozomu Ikuno Kazuki Ishii Hongying Hu 《Frontiers of Environmental Science & Engineering》2019,13(4):55
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