Predicting geological hazards during tunnel construction

The complicated geological conditions and geological hazards are challenging problems during tunnel construction,which will cause great losses of life and property.Therefore,reliable prediction of geological defective features,such as faults,karst caves and groundwater,has important practical significances and theoretical values.In this paper,we presented the criteria for detecting typical geological anomalies using the tunnel seismic prediction（TSP） method.The ground penetrating radar（GPR） signal response to water-bearing structures was used for theoretical derivations.And the 3D tomography of the transient electromagnetic method（TEM） was used to develop an equivalent conductance method.Based on the improvement of a single prediction technique,we developed a technical system for reliable prediction of geological defective features by analyzing the advantages and disadvantages of all prediction methods.The procedure of the application of this system was introduced in detail.For prediction,the selection of prediction methods is an important and challenging work.The analytic hierarchy process（AHP） was developed for prediction optimization.We applied the newly developed prediction system to several important projects in China,including Hurongxi highway,Jinping II hydropower station,and Kiaochow Bay subsea tunnel.The case studies show that the geological defective features can be successfully detected with good precision and efficiency,and the prediction system is proved to be an effective means to minimize the risks of geological hazards during tunnel construction.     

氯丙烯环氧化反应器气相安全控制条件

在相转移法氯丙烯环氧化反应过程中,由于少量双氧水发生无效分解生成氧气,导致反应器气相存在燃爆危险性。测试了工况条件下氯丙烯-氧-氮三元体系的燃爆特性,得出该体系的极限氧浓度值(LOC)为10.9%;考察了主要因素对气相氧浓度的影响。研究发现,要降低气相氧浓度,应尽可能降低催化剂用量,适当提高搅拌速度,严格控制H_2O_2用量;应在液相沸腾后开始H_2O_2进料,并控制反应初始阶段的H_2O_2进料量,以避免瞬间H_2O_2进料过快。     

离子膜烧碱装置的主要化学品危害及工业设计中的防治措施

文章结合湖北某厂离子膜烧碱装置的部分设计内容探讨离子膜烧碱装置中主要化学品危害及工业设计中可采取的一般防治措施。在总图布置上按照相关规范的要求和场地的实际情况合理安排各装置的相对位置和安全间距,并在设计中结合各化学品的具体物质特性,由工艺、设备、自控、电气、建筑、结构、给排水等专业的采取综合防治措施,能够保证离子膜烧碱装置的安全、稳定、长期、优质运行。     

基于掌子面编录和地质雷达的综合超前预报技术

 结合一深埋长大隧道工程,提出并实践基于掌子面编录和地质雷达的综合超前预报技术。在区域工程地质资料分析的基础上,重点依托隧道内掌子面地质素描进行预报方案优化和选择预报时机;依据局部揭露的不良地质体产状、单壁始见位置,通过三角函数运算,求得该条带状不良地质体在隧道两壁上下和拱顶的边界位置及其影响长度;当接近特殊地质地段时,采用地质雷达进行更精确的短期预报,依据雷达反射波的振幅、相位及频率等变化探查断层和地下水的赋存情况。对于较大范围的不良地质体,采取连续跟踪预报的策略,通过多次预报成果的验证及反馈能够显著提高预报的可靠性。该综合超前预报方法在隧道穿越断层和涌水段施工中取得满意的效果。     

深基坑支护的低环境危害分析

随着高层建筑的发展,深基坑支护技术已成为建筑工程领域关注的问题之一,然而由此引发的环境问题也随之而来。该文主要分析了城市深基坑工程施工对环境的影响及可能引发的灾害,提出了相应的环境保护措施,并就武商摩尔城用MIDAS进行了计算机模拟分析,验证施工方法的安全性。     

电子设备的防静电接地技术

从工程应用的角度出发,分析静电放电对于电子设备、工作人员和工作场所的4种主要危害:引发火灾或爆炸、干扰系统工作、损坏电子器件、致人电击。阐述采取接地的方式防范静电危害的基本原理;重点论述电子设备防静电的接地要求和实用接地技术措施。     

建筑火灾烟气危害评价模型及应用

在FED理论基础上,参考SII烟气伤害模型提出一个考虑烟气温度、能见度和毒性综合作用的人员伤害模型,并在该模型基础上开发基于GIS的火灾烟气危害评价系统。该系统可以确定建筑室内火灾中烟气综合危害分布和毒性分布随时间变化的情况,并得出性能化防火设计重要参数之一ASET,为火灾人员疏散提供参考依据。     

Critical review of methods for risk ranking of food-related hazards,based on risks for human health

This study aimed to critically review methods for ranking risks related to food safety and dietary hazards on the basis of their anticipated human health impacts. A literature review was performed to identify and characterize methods for risk ranking from the fields of food, environmental science and socio-economic sciences. The review used a predefined search protocol, and covered the bibliographic databases Scopus, CAB Abstracts, Web of Sciences, and PubMed over the period 1993–2013.

All references deemed relevant, on the basis of predefined evaluation criteria, were included in the review, and the risk ranking method characterized. The methods were then clustered—based on their characteristics—into eleven method categories. These categories included: risk assessment, comparative risk assessment, risk ratio method, scoring method, cost of illness, health adjusted life years (HALY), multi-criteria decision analysis, risk matrix, flow charts/decision trees, stated preference techniques and expert synthesis. Method categories were described by their characteristics, weaknesses and strengths, data resources, and fields of applications.

It was concluded there is no single best method for risk ranking. The method to be used should be selected on the basis of risk manager/assessor requirements, data availability, and the characteristics of the method. Recommendations for future use and application are provided.     

反式脂肪酸生成机理的研究

反式脂肪酸的危害越来越被人们所熟知。反式脂肪酸的形成机理也各不相同。食品中的反式脂肪酸主要来自于反刍动物代谢过程中生成与食品加工过程中形成的反式结构的脂肪酸。反刍动物体内的反式脂肪酸是由氢化细菌-丁酸弧菌酶促氢化作用下形成。植物油氢化工艺中,在金属催化剂参与下产生反式异构体。在高温烹调条件下,发现反式脂肪酸含量不断增加,通过量子化学密度泛函理论推导(能量计算)与试验验证相结合,发现在150°或更高的温度下油酸发生异构化生成反式油酸。     

全岩巷综掘面综合防尘技术及应用

为了解决全岩巷综掘面高浓度粉尘危害问题,提出了构建以降尘泡沫、除尘风机为主,以分级净化水幕、个体防护为辅的综合控(除)尘体系,并在张集矿1123(3)~1124(3)瓦斯底抽巷综掘现场进行应用,结果表明:司机处测得的总粉尘和呼吸性粉尘的降尘率分别为92.5%和96%,配合个体防护及净化水幕,有效地治理了掘进巷道粉尘危害。