基于子集模拟的埋地管道失效概率评估

对失效概率的评估是管道系统风险评价的核心内容,针对目前对埋地管道失效概率问题研究的不足,采用子集模拟方法（SS）建立埋地管道失效概率的定量评估模型以及参数敏感度模型,并对随机变量进行敏感分析。研究结果表明:子集模拟能利用少量样本定量计算出管道失效概率,有效弥补了管道结构可靠性模型中的不足;在管道运行中期,工作压力、腐蚀速率、管道壁厚和屈服强度是对管道失效概率影响较大的4个因素,而腐蚀因素在管道运行后期成为对系统失效概率影响最大的因素。     

酸析—撞击流旋转填料床强化Fenton试剂氧化法预处理二硝基甲苯生产废水

采用酸析—撞击流旋转填料床( IS-RPB)强化Fenton试剂氧化法预处理二硝基甲苯(DNT)生产废水.最佳工艺条件为:酸析工段废水pH 1.0,IS-RPB转速1 500 r/min,FeSO4加入量0.06 mol/L,H2O2加入量0.45mol/L,反应温度40 ℃,反应时间4h.在该条件下处理DNT生产废水,COD去除率可达98.95％,硝基化合物去除率达98.32％,BOD5/COD为 0.65.经该方法预处理后的DNT生产废水可适用于生化法进行后续处理.     

零价铁-Fenton试剂体系降解有机污染物的研究进展

零价铁-Fenton试剂体系在对许多有机污染物有着较好的处理效果的同时,有效地克服了单独零价铁还原与传统Fenton反应的缺点.本文分析了零价铁-Fenton试剂体系的作用机理,总结了零价铁-Fenton试剂体系在处理有机污染物中的新进展,介绍了零价铁-Fenton试剂体系与其他技术联用降解有机污染物的研究成果.并讨论了对该反应有较大影响的几种因素.针对目前的研究中出现的一些问题,结合实际的需要,提出了今后需关注的研究方向.     

USING SENSITIVITY ANALYSIS TO ASSIST PARAMETER ZONATION IN GROUND WATER FLOW MODEL1

ABSTRACT: For numerical modeling of ground water movement in a real aquifer system, the aquifer is usually divided into hydrogeologically defined zones, each with its own parameter values. The responses of the system, such as head or drawdown, are often available only in some of the zones. The estimated parameters of all the zones are based on the measured response in these limited zones. However, the estimates for some of the zones may be very uncertain, and these zones are therefore not justified by the data. In this paper, an approach is presented to understand which zone may produce uncertain parameter values and should be lumped with its neighbor. This approach is demonstrated using a regional numerical model for pumping test analysis in the Nottinghamshire aquifer, UK. A step-by-step process is used in identifying the aquifer zones and estimating their parameters based on the principle of using the smallest possible numbers of zones and parameters for adequate representation of the drawdown response. After the parameters of each zone are estimated, the sensitivity features of these parameters are examined. The results show that the parameters in one zone can be estimated properly by the drawdown in another zone only when there is significant sensitivity. For transmissivity, sensitivity between zones occurs when there is significant flow between them. For storativity, sufficient sensitivity can occur without large flows between the zones, provided that one zone causes significant drawdown in the other. This idea can be extended to the flow model for a large aquifer system. If the aquifer is divided in such a way that aquifer responses are not sensitive to the parameters in some of the zones, the parameters in those zones cannot be estimated properly and should be lumped into their neighboring zones. In this way, a simple but more reasonable model can be built.     

OPTICAL IMPACTS AND SOURCES OF SUSPENDED SOLIDS IN ONONDAGA CREEK,U.S.A.1

ABSTRACT: The degradation of the optical aesthetics in the mouth of Onondaga Creek, New York, that occurs during high flow periods as a result of the influx of large quantities of suspended solids, is documented. Features of the degradation include very low clarity (Secchi disc minimum of approximately 0.1 m) and a brown ‘muddy’ appearance. The reduced clarity is mostly a result of increased light scattering. Loading and concentration profiles obtained for an approximately 35 km interval above the creek mouth over a wide range of flow indicates most of the suspended solids received during runoff events is resuspended stream sediment and eroded bank material. Application of microscopy-based individual particle analysis techniques indicates that the origin of most of these deposits and much of the suspended solids during runoff events is point source inputs, termed ‘mud boils,’ located approximately 32 km upstream of the creek mouth.     

活性炭吸附缓冲非稳态VOCs研究进展

活性炭类吸附剂可以有效地缓冲挥发性有机物(VOCs)的浓度负荷波动。综述了活性炭对非稳态VOCs吸附缓冲的作用原理及类型,从吸附剂、吸附质、进气性质和设备及操作条件等方面讨论了影响吸附缓冲性能的因素,并对今后该领域的研究方向提出了展望。指出:应当进一步研究吸附剂和吸附质的交互作用、波动负荷的影响以及VOCs在活性炭中的迁移扩散现象;同时,通过深层次的实验测试和模型模拟为反应器的设计和操作参数的估算提供指导。     

卡尔·阿曼

卡尔·阿曼（Karl Ammann）,1948年出生于瑞士圣加伦,是著名的野生动物摄影家,生物多样性保护者和经济学者,也是世界野生动物保护协会、猎豹保护基金会等多个非政府组织的顾问。     

卡尔·阿曼

卡尔·阿曼(Karl Ammann),1948年出生于瑞士圣加伦,是著名的野生动物摄影家,生物多样性保护者和经济学者,也是世界野生动物保护协会、猎豹保护基金会等多个非政府组织的顾问.     

比尔·邓斯特

比尔·邓斯特(Bill Dunster)1960年生于英国,毕业于爱丁堡大学,获硕士学位.是世界上为数不多,专注于零能耗建筑的设计师.他不仅在英国,而且在其他国家也大力推广零能耗建筑理论,取得了不少的成果.在对高密度可持续发展住宅进行了多年的研发之后,比尔为皮伯迪住宅信托公司(Peabody Housing Trust)设计了贝丁顿零能耗社区(BedZED).     

沘江兰坪段生态健康评价指标体系研究

河流是人类文明的发源地。它为人类提供了多样的生态服务,但随着工业文明的发展,大量废水和污染物的排入,河流生态健康受到了严重影响。本文以沘江兰坪段为例,根据整体性原则、层次性原则、可操作性原则和定性与定量结合的原则,参考国内外河流生态健康评价的指标体系,结合沘江具体情况对河流生态健康的评价指标体系进行了探讨。