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221.
刘利亚 《中国个体防护装备》2010,(3):24-27
本文介绍了正压呼吸器佩戴者呼出来的气体再次被利用,补偿系统的吸气气源,使之达到其系统工作的气体传动及协调平衡系统的目的,极大地延长呼吸器的使用时间。 相似文献
222.
D. Williams B. A. Emmett S. A. Brittain B. Reynolds P. A. Stevens D. Benham 《Water, Air, & Soil Pollution: Focus》2004,4(6):187-196
A field-based system used to quantify the response of acid grassland to reduced atmospheric nitrogen and sulphur deposition, and to investigate the effects of elevated soil temperature on acid grassland development is described. The system is based on 12 retractable roofs, covering undisturbed experimental plots of acid grassland and three controls. Nine roofs are used to exclude natural precipitation and three roofs used to retain emitted IR radiation at night. An irrigation system has been developed to simulate natural precipitation, allowing for the application of specific treatment regimes of ambient, reduced nitrogen and reduced nitrogen/sulphur deposition beneath the nine rain exclusion plots. Plant, soil parameters, leachate chemistry and gaseous fluxes are being monitored and initial results on soil water chemistry are described. Warming appeared to enhance nitrate concentrations in soil water but this was not sustained beyond the first year of treatment. In contrast, the deposition reduction treatments decreased soil water nitrate concentrations within a few weeks of reducing deposition. This was not observed for other solutes such as sulphate or ammonium suggesting a more direct link between deposition of nitrate and leaching losses. 相似文献
223.
Lijie Zhou Hongwu Wang Zhiqiang Zhang Jian Zhang Hongbin Chen Xuejun Bi Xiaohu Dai Siqing Xia Lisa Alvarez-Cohen Bruce E. Rittmann 《Frontiers of Environmental Science & Engineering》2021,15(1):16
224.
不同地区、排水体制和季节下,我国城市污水厂进水中细微泥沙含量〔以ρ(ISS)/ρ(CODCr)表征,ISS为无机悬浮固体〕差异较大,细微泥沙进入生化处理单元将会对活性污泥系统的正常运行产生一定影响. 考察在不同进水细微泥沙浓度下,活性污泥系统各运行参数的变化及系统恢复情况,结果表明:①随着进水中细微泥沙浓度的增大,活性污泥系统ρ(MLVSS)/ρ(MLSS)、SOUR′(单位质量污泥活性)、CST(污泥毛细吸水时间)和SVI(污泥容积指数)降低;在影响期,ρ(MLVSS)/ρ(MLSS)最小值、SOUR′平均值、CST平均值与细微泥沙浓度均呈良好的线性关系,R2(相关系数)分别为0.963 7、0.979 9和0.786 5;系统恢复所需时间与进水细微泥沙浓度呈正相关. ②污泥中细微泥沙浓度的增加导致SOUR′下降,使得ρ(MLSS)和剩余污泥量增加,不利于污水厂的节能减排. 可见进水中细微泥沙浓度的增大不利于污水厂的稳定高效运行. 相似文献
225.
液体吸收法应用于处理工业有机废气涉及到2个关键因素,即吸收剂的选择与吸收液的再生处理. 选择8种水溶性吸收剂——2种氟碳表面活性剂(FSO100和FSN100)、2种非离子表面活性剂〔TW80(吐温80)和SP20(斯盘20)〕、2种阴离子表面活性剂〔脂肪醇聚氧乙烯醚硫酸钠(AES)和脂肪醇聚氧乙烯醚羧酸钠(AEC)〕及2种类表面活性剂〔β-CD(β-环糊精)和SA(乙酸钠), 对模拟甲苯废气进行了动力学吸收试验,研究吸收性能和加热蒸馏法对甲苯回收与吸收剂溶液再生的可行性. 结果表明:吸收剂类型是影响甲苯吸收能力的最主要因素. 2种氟碳表面活性剂吸收液的甲苯吸收能力最强,其次是SP20与AES,而其他4种吸收剂溶液对甲苯的吸收能力很弱. 上述3类吸收剂对甲苯的初始去除率分别为80%~90%、75%左右与60%~70%,甲苯饱和吸收浓度(以w计)分别为0.58~3.45、0.38~1.44与0.14~1.01 mg/g. 除TW80吸收液热稳定性差、不宜采用加热蒸馏方法再生外, 其他吸收剂溶液经5次重复使用,甲苯回收率可达70%~85%,并能保持其原有吸收性能. 甲苯分配系数计算结果表明,FSO100和FSN100分别为0.41、0.62, SP20和AES分别为0.76、0.95, 其他4种吸收剂溶液在1.12~3.54之间;甲苯分配系数与饱和吸收浓度呈负相关、与体积传质系数呈正相关. 因此,2种氟碳表面活性剂吸收液对甲苯的吸收能力强,加热蒸馏法回收甲苯与再生吸收液具有经济性,用于处理甲苯废气具有广泛的应用前景. 相似文献
226.
227.
Daniel Abrahams 《Disasters》2014,38(Z1):S25-S49
Disaster recovery operations that do not account for environmental sustainability (ES) risk exacerbating the impact of the disaster and hindering long‐term recovery efforts. Yet aid agencies do not always consider ES. This research is a case study of the recovery that followed the 2010 earthquake in Haiti. Using timber and concrete procurement as proxies for broader post‐disaster operations, research examined perceptions of ES as well as attempts at and barriers to incorporating it into programming. Identified barriers can be grouped into two categories: (1) prioritisations and perceptions within the disaster response sector that resulted in limited enthusiasm for incorporating ES into programming, and (2) structural and organisational barriers within the disaster response framework that impeded ES attempts and served as a further disincentive to incorporating ES into programming. As a result of those barriers, incorporation of ES was sporadic and inconsistent and often depended on the capacity and motivation of specific implementers. 相似文献
228.
Guat Tin Ng 《Disasters》2014,38(2):310-328
This paper reports on the results of a qualitative study on the responses of Chinese school children in one junior middle school and their parents to China's post‐disaster school relocation policy. The sample comprised 22 pairs of parent–child dyads and two pupils whose parents could not be contacted. The study results were reported using Chambers and Wedel's (2009) conceptual framework, which delineates the fundamental elements of a policy. Content analysis was used to generate themes related to policy elements, such as goals, benefits and services. Both repetitive themes and idiosyncratic perspectives were reported so as to present a diversity of views. Despite adjustment difficulties and administrative problems reported by the study participants, the policy attention given to the rapid restoration of formal schooling for children was generally appreciated. The move back to the new school was greeted with cheer. 相似文献
229.
《Process Safety and Environmental Protection》2014,92(6):849-861
Resource depletion is of concern to both present and future generations in terms of access to resources. It is a prominent impact category within life cycle assessment (LCA) and sustainability assessment. This paper examines existing resource depletion approaches and indicators in the context of natural gas depletion, and their limitations in modelling the wider environmental consequences of resource consumption. Some existing models assume substitution of scarce fossil fuels with an alternative fossil fuel or mix, but do not consider all of the subsequent change in impacts. An additional methodology is proposed to measure the impact changes when fossil fuel substitution occurs as a result of scarcity. The methodology will demonstrate the effect of resource scarcity for individual processes but also multiple processes which operate at different levels of resource consumption with varying degrees of impacts. The methodology is applied to a scarcity situation of natural gas in Australia, where black coal is substituted for gas. It is first applied to natural gas consumed for electricity generation only. In the second case, the methodology is applied to the substitution of natural gas for both electricity generation and hydrogen production. The varying impacts on emissions to air and water, together with solid waste generation and water depletion, as a result of the substitution are used to reflect the consequences of fossil fuel depletion. The indicators also provide information on the impacts of substitution in each product, thus enabling users to prioritise products based on the impacts produced during natural gas allocation. 相似文献
230.