Pressure-assisted chelation extraction of lead from contaminated soil

Soil contamination by metallic elements including lead occurs frequently. Contaminant metals in soil pose a serious risk to public health and groundwater supplies. Extraction using chelants is seen as a remediation option; however, it is often hampered by access to the contaminants that are shielded by the soil matrix. We have developed a novel extraction technique that utilizes a mildly elevated pressure in consecutive cycles of compression and decompression along with a chelating agent for the soil slurry. Complete extraction of 3300 mg/kg of Pb from soil was achieved by 100 mM of EDTA (ethylenediaminetetraacetic acid) in 10 min using 20 pressure cycles at 150 psi (10 atm). Extraction was studied according to pressure, number of pressure cycles, chelant concentration, solid content, pH, agitation, and use of consecutive washings. Heightened extraction is attributed to fracturing of the soil particles that leads to enhanced contaminant exposure to the chelating agent.     

汽车轮胎气压监测系统发展综述

轮胎气压监测系统是汽车上一种新的主动安全技术产品,近年来,在国内外发展迅速。由于它能够实时监测汽车轮胎的气压和温度情况,并能及时给驾驶员以警告,因而可以最大限度地避免由爆胎引发的交通事故,提高了汽车的行车安全。综述了汽车轮胎气压监测系统的发展,包括间接式轮胎气压监测系统、直接式轮胎气压监测系统和下一代无电池轮胎气压监测系统(被动式TPMS)。介绍了各种汽车轮胎气压监测系统的结构组成和工作原理,分析比较了它们各自的优缺点。重点介绍了国外3种主流的直接式TPMS开发系统,对TPMS的研究、开发具有实用参考意义。展望了未来轮胎气压监测技术的发展趋势:无电池TPMS将取代现有类型,成为未来TPMS发展的主流。     

Application and sensitivity testing of a eutrophication assessment method on coastal systems in the United States and European Union

The Assessment of Estuarine Trophic Status (ASSETS) screening model has been extended to allow its application to both estuarine and coastal systems. The model, which combines elements of pressure, state and response, was tested on four systems: Maryland Coastal Bays and Long Island Sound in the United States and The Firth of Clyde (Scotland) and Tagus Estuary (Portugal) in the European Union. The overall scores were: Maryland Coastal Bays: Bad; Firth of Clyde: Poor; Tagus Estuary: Good. Long Island Sound was modelled along a timeline, using 1991 data (score: Bad) and 2002 data (score: Moderate). The improvement registered for Long Island Sound is a consequence of the reduction in nutrient loading, and the ASSETS score changed accordingly. The two main areas where developments are needed are (a) In the definition of type-specific ranges for eutrophication parameters, due to the recognition that natural or pristine conditions may vary widely, and the use of a uniform set of thresholds artificially penalizes some systems and potentially leads to misclassification; (b) In the definition and quantification of measures which will result in an improved state through a change in pressures, as well as in the definition of appropriate metrics through which response may be assessed. One possibility is the use of detailed research models where different response scenarios potentially produce changes in pressure and state. These outputs may be used to drive screening models and analyze the suitability of candidate metrics for evaluating management options.     

基于全过程治水理念的城市水环境系统综合整治效果评价

采用压力-状态-响应(PSR)和层次分析法(AHP)构建基于全过程治水理念的城市水环境系统综合整治效果评价体系,并对深圳前海铁石片区水环境综合整治项目进行评价.结果表明,关注河道本身的安全、环境、生态等指标,且考虑污水产生后源头削减、收集、集中处理、输送的全过程,可有效评估城市水环境综合整治效果,项目评价结果为良好.     

井喷事故H2S扩散环境三维建模与仿真

针对四川某地井喷事故H2S气体泄漏扩散问题,建立了井喷事故发生地复杂地形的三维模型,并进行了仿真模拟计算.     

我国防灾救灾物资市场建立过程中的企业行为与对策探讨

在社会主义市场经济条件下,防灾救灾物资也同样需要通过市场配置,而不是通过计划调拔。在目前及今后一段时期迫切需要研究并适应灾害特点,迅速建立适合中国国情的防灾救灾物资市场体系,变政府开发为市场开发,逐步使企业发展成为防灾救灾物资市场开发的主体。     

破坏性地震事件前后的紧急事务处理和震后紧急救援

根据我国目前的地震应急现状,提出了破坏性地震事件前后的紧急事务处理和震后紧急救援的有关问题以及二者之间的关系,论述了国际救援在大城市发生特大破坏性地震中的作用.     

闽江流域公众对工业企业外部环境压力的认知

企业外部环境压力的强弱对解决我国环境问题起着决定性的作用。通过对闽江流域公众对工业企业外部环境压力认知的调查研究,一方面了解到目前公众的环境保护意识,另一方面从公众的角度看政府、新闻媒体、科研机构、金融保险机构以及公众自身在环境保护中的作用,反映出闽江流域企业外部环境压力现状与存在的问题,从而针对问题提出闽江流域环境保护的对策。     

Evaluation of septum-capped vials for storage of gas samples during air transport

In order to provide information on the suitability of commonly used gas storage vials for air transport, we tested two vial types on their ability to preserve defined nitrous oxide concentrations and excess pressure when exposed to low pressure, low temperature and puncture by needles. Unlike in Crimp Cap vials, in Exetainers no nitrous oxide loss following low pressure storage was detectable. Tightness of Exetainers following multiple puncture was best using a small needle diameter. Pressure loss following 5, 10, or 25 punctures was lowest in the Exetainers. We conclude that Exetainers are suitable for storing gas samples for an extended period of time during aircraft transport.     

电站锅炉的压力管道管理和检验要求分析

电站锅炉的压力管道参数较高,存在着较大的安全风险,一旦发生事故,后果往往十分严重.电站锅炉的压力管道在按照"锅炉"或"压力管道"进行管理时,设计、制造、安装等阶段管理要求存在交叉或不清晰的情况.进行定期检验时,又有按锅炉范围内管道或工业管道(含动力管道)执行不同技术规范的情况.本文通过按"锅炉"和"压力管道"管理时执行...