Effects of rainfall infiltration on deep slope failure

With the finite element method and the limit equilibrium method, a numerical model has been established for examining the effects of rainfall infiltration on the stability of slopes. This model is able to availably reflect the variations in pore pressure field in slopes, dead weight of soil, and the softening of soil strength caused by rainfall infiltration. As a case study, an actual landslide located at the Nongji Jixiao in Chongqing is studied to analyze the effects of rainfall infiltration on the seepage field and the slope stability. The simulated results show that a deep slope failure is prone to occur when rainfall infiltration will lead to a remarkable variation in the seepage field, in particular, for large range pore water pressure increase in slopes. Supported by the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No. KJCX2-SW-L1-4) and the Major State Basic Research Development Program of China (Grant No. 2002CB412703)     

Results of 0.5% cold-leg small-break LOCA experiments at ROSA-IV/LSTF: Effect of break orientation

Three 0.5% cold-leg small-break loss-of-coolant accident (SBLOCA) experiment were conducted at the ROSA-IV Large Scale Test Facility (LSTF) to investigate the effects of break orientation on system thermal-hydraulic responses. In these three experiments, the break hole was located at the side, bottom, and top of the horizontal cold leg, respectively. Although the key phenomena observed in the three experiments were basically the same, the break flow rate was affected by the break orientation when phase stratification occured in the cold leg; the break flow rate was largest for the side break and smallest for the top break. The RELAP5/MOD2 code failed to predict the difference in the break flow rate observed in the experiments. Modification to the break flow calculation models, for both subcooled and two-phase flow discharge conditions, resulted in good agreement between data and predictions.     

利用水下爆炸法评价火炸药爆炸危险性的研究

本文提供了一种测定火炸药冲击感度,并根据测定值判定其冲击爆炸危险性的新方法测定水下爆炸气泡能法。通过对30几种炸药的试用,判定的结果与文献报道的用其他方法判定的结果相当好的一致。而且本法的优点还在于同时可得到试样的动、静态威力,操作简便、安全、噪音小。此外,利用本试验法还探讨了炸药形态、惰性介质(水)对冲击感度的影响。这些对于处理炸药时应如何采取安全对策具有指导意义。     

BEWARE OF THE BEACH HIDDEN KILLER--RIP CURRENT

离岸流是垂直于海岸线、向外海方向快速移动的强劲海流。对于海边的人员来说非常危险,没有经验的游泳者一旦被离岸流带离浅滩,很难与之对抗游回岸边,往往因力竭而溺水。每年海滨区域都有大量的溺亡事件与此相关,但有关离岸流的知识在公众的视野里仍比较缺乏。本文从流体力学的角度对离岸流的危害、形成、特征以及分类进行了简要介绍,并在如何防范离岸流、保障自身安全等方面给出了一些建议。     

非高斯随机激励下工程结构可靠性估计的一种方法

本文将工程结构考虑为振动系统,把随机载荷及在结构上的载荷效应作为随机过程,分析状态函数的高阶矩,进行最大熵概率分析,得到结构在随机载荷作用下失效的概率。此法为随机环境下工作的结构、构件或设备的安全设计、可靠性检验提供了一个可行的方法。     

借鉴美国主流高校EHS体系建设我国的实验室安全文化

以美国化学类专业排名前30的高等院校的环境安全与健康管理体系(Environment,HealthSafety,简写为EHS)为研究对象,进行了信息的收集、分析与整合,从中总结出美国高校EHS管理体系的6个特点;进一步介绍了美国高校EHS管理体系架构的确立与运作。结合目前我国高校实验室安全管理存在的主要问题,提出了建设、发展和丰富我国高校的实验室安全文化是当前最基础性的建设任务之一,以期引起高校管理部门对安全问题的真正重视并落实到行动中。     

微流控芯片电泳在食品安全与环境污染检测中的应用

微流控芯片电泳具有样品和试剂消耗量小、分析速度快、分离效率高以及便于微型化等特点,特别适合于食品安全和环境污染相关的现场快速检测。该文综述了微流控芯片电泳技术在食品安全与环境污染检测方面的研究进展,着重介绍了该技术在食品中有害物质残留、非法食品添加剂以及环境样品中有害无机离子、有机污染物等目标物检测方面的典型应用实例,在此基础上初步讨论了微流控芯片电泳走向实际应用面临的问题和可能的解决办法。     

“禁摩限电”效果综合评价模型

将交通需求级别进行划分后,通过数据包络分析法计算交通需求匹配度和交通运行效率,近乎绝对细化交通运行表现,依据具有时间轴的四维交通状况模拟建立了全新多维度的交通评价体系。此外,利用模糊层次分析法确定道路交通安全评价指标体系中各个指标的权重,同时作出基于差异驱动原理的综合评价。最后,将交通的污染指标提炼为机动车的排放指标和电动车的耗电指标来衡量交通工具对环境的影响。     

基于权重比的民航飞行员安全行为指标权重算法

确定飞行员安全行为指标的权重,对发现民航飞行员飞行安全风险的短板,提高民航飞行安全性具有重要意义.基于指标权重比,提出了一种飞行员安全行为指标权重算法.并以此算法分析了职业安全意识、飞行情景意识、特情应变能力以及机组资源管理能力等指标对飞行员安全行为的影响程度,研究可为飞行员安全行为风险管理提供依据,对安全飞行具有积极的指导意义.     

IMEP-24 analysis of eight trace elements in toys

The International Measurement Evaluation Program (IMEP) organised the IMEP-24 interlaboratory comparison after reports in the media about high levels of lead in toys. The aim of this comparison was to verify the laboratories’ capacity to evaluate trace-element levels in a possible toy-like material according to the European Standard EN 71-3:1994. As test material, it used a former certified reference material containing levels of antimony, arsenic, barium, cadmium, chromium, mercury, lead and selenium around the limits set in the standard.Four expert laboratories confirmed the reference values (Xref) for all elements but Hg, and established a reference value for Hg. The scatter of the results reported by the participants was large, as expected, but showed a close to normal distribution around the reference values for five of the eight trace elements. The spread of results was mainly attributed to sampling and sample preparation.One major issue observed in this exercise was the lack of legislative rules about how to report the result, or, more specifically, the use of the analytical correction, which was introduced in EN 71-3:1994 to achieve consistent interpretation of results and which is to be applied when values are equal to or above the maximum limits set in the standard. Its application by the participants was very inconsistent and led to problems in their evaluation. There is clearly a need for clarification and for more formal regulations with regard to result reporting in order to minimise the risk of confusion.Participants were also asked to give their opinion with regard to the acceptability of the test material for the market. The majority correctly considered the material as non-compliant. However, almost one-third incorrectly assessed the material as compliant.