造成机械伤害的原因及预防

日常工作中,由于机械伤害常常给人造成痛苦,甚至终身残疾。怎样才能有效地防止机械伤害事故呢?首先要正确分析产生机械伤害事故的原因,然后采取相应的安全防范措施。形成机械伤害事故的原因: 1.修理、检查机械时,忽视安全措施。在线检修时,未采取必要的预防措施;断电作业,电源处未悬挂警示牌。 2.安全防护装置不健全或形同虚设。 3.电源布局混乱,不利于紧急停车。 4.违章作业,随便进入危险作业区。 5.不熟悉操作规程,遇有紧急情况发生判断错误。     

国内外大城市防灾减灾管理模式的比较研究

城市综合防灾减灾管理是城市管理的一个重要组成部分。上海综合减灾体系目前尚不够完善，城市抗灾能力仍较薄弱。本文通过对国外大城市减灾管理模式的比较和研究，分析了目前上海市减灾管理模式的现状和问题，提出了改进目前上海市灾害管理模式的措施建议。     

防旱抗旱能力综合评价方法：—以关中地区为例

本文采用11项指标并确定相应的评分标准和权重分配,对关中地区进行防旱抗旱能力的综合评价,得出关中地区属中等抗旱能力区。由于经济发展需水超过供水能力,现状及本世纪末缺水率将超过20％。因而跨流域引水是今后长期供水的途径。     

Hydrogen sulfide effects on ammonia removal by a biofilter seeded with earthworm casts

Ammonia (NH3) removal efficencies were evaluated when hydrogen sulfide (H2S) and NH3 in binary mixture gases were supplied to a ceramic biofilter seeded with earthworm (Lumbricus terrestris) casts. The effect of inlet H2S concentration and space velocity (SV) on the removal of NH3 was investigated after the acclimation of the biofilter with NH3 gas. When NH3 was singly supplied to the biofilter, NH3 removal was maintained at almost 100% until inlet NH3 concentration was increased up to 600 microL L(-1) and SV up to 330 h(-1), at which the elimination capacity of NH3 was 148 g N m(-3) h(-1). When H2S was supplied simultaneously, however, the accumulation of toxic sulfide ions showed dual effects on NH3 removal efficiencies. First, no effects were observed at inlet H2S loading below 60 g S m(-3) h(-1); however, inhibition by H2S at higher loading was observed above 60 g S m(-3) h(-1). The point at which loading achieved a maximum of more than 99% NH3 removal efficiency was 139 g N m(-3) h(-1), when inlet H2S concentration was held under 100 microL L(-1), but it dropped to 76 and 30 g N m(-3) h(-1) when the inlet H2S concentration increased to 220 and 460 microL L(-1), respectively. The critical points of inlet H2S loading that guaranteed over 99% NH3 removal were determined as 100, 100, 60, and 40 g S m(-3) h(-1) at inlet NH3 concentrations of 100, 200, 400, and 600 microL L(-1), respectively. Inlet NH3 loading had synergic effects of increasing the inhibition of inlet H2S loading on the NH3 removability of the biofilter.     

关于城市应急供水系统建设的思考

从城市应急供水系统建设的紧迫性和重要性出发,分析了目前我国城市应急供水系统存在的问题和造成城市非常供水的原因。构建了城市应急供水系统的框架,将其分成工程措施和非工程措施两部分,并阐述了工程措施的类型和实施方法,以及非工程措施的各项应急机制,对建立、健全城市应急供水系统进行了探讨。     

Research of Toxic Mechanism on Anaerobic Digestion by Lead

The paper analyzes the influence of lead toxicity by anaerobic granule sludge inhibition and recovering experiments. The result shows that there are different inhibition types at different lead contents. Higher lead content leads to more inhibition granular sludge, and at the same time, the time of gas recovery is different. Lower lead content per microorganism results in sooner sludge recovery. Microorganisms have a good ability to resist lead toxicity.     

落石冲击作用下架设油气管道响应分析

针对影响油气管道安全运营的落石冲击问题,基于弹塑性力学、Cowper-Symonds本构模型和有限元方法,建立了球形落石冲击油气管道的计算模型,对管道动态响应过程进行了数值模拟。对冲击速度、落石半径、管道内压力和落石冲击位置进行了参数敏感性分析,研究了各参数对管道冲击变形的影响规律。结果表明:落石的冲击能量主要用于管道塑性变形;冲击过程中,落石与管道的接触区域由初始的椭圆斑逐渐变成了椭圆环;管道塑性变形随着冲击速度和落石半径的增大而增大,随内压和落石偏移度的增大而减小。该研究工作为油气管道的安全评价及防护工程的设计提供了参考依据,对保障油气安全运输具有重要的工程意义。