Investigation on working fluids selection for organic rankine cycles with low-temperature heat sources

The Influence of mixed and pure working fluids on the performance of organic Rankine cycles (ORCs) is discussed. Specifically, the performance of mixed and pure working fluids is analyzed based on certain characteristics of low-temperature heat source and heat sink. A method of selecting binary zeotropic mixed working fluids that match with different heat sinks is introduced. Thermodynamic processes of ORCs for various heat sources are simulated in Matlab. The performance characteristics of pure and mixed working fluids are compared under different inlet temperatures and temperature gradients of sensible heat sources. The results demonstrate that when the initial temperature of a heat source is lower and its temperature gradient is higher, and the temperature gradient of the heat sink is higher, mixed working fluids have better performance than pure working fluids. However, for the opposite heat source and heat sink situations, pure working fluids perform better. Mixtures with low critical temperature components exhibit the best performance among all working fluids when the temperature gradient of the heat source is large. The analysis also shows that introduction of a recuperator may reduce the cycle efficiency when the heat source temperature is low and the temperature gradient of the heat source is large.     

洪水灾害间接经济损失评估研究进展

受全球气候变化及人类活动的影响,洪水灾害发生的频率和损失越来越大,洪灾直接经济损失评估研究不断深入,但是,洪灾间接经济损失评估研究相对薄弱。为了能综合地对洪水灾害间接经济损失进行科学的评价,回顾了国内外洪水灾害间接经济损失评估的研究现状,综述了洪水灾害间接经济损失的内涵及组成(减产停产损失、产业关联损失和投资溢价损失),分析了他们之间的关系及相应的评估方法特点。指出洪水灾害间接经济损失主要指产业关联损失,投入产出法是间接经济损失评估的适用方法,但该方法的使用必须作适应性改进,上述观点可供洪灾间接经济损失评价参考。     

浅析灾害间接经济损失评估的重要性

灾害损失评估是灾害风险管理、科学防灾减灾规划的基础。除了直接经济损失外,间接经济损失是反映灾害影响强度及社会经济系统脆弱性的重要指标。经济越发达,经济系统关联程度越高,经济系统的脆弱性就越大,灾害间接经济影响也越大。已有研究表明,灾害间接经济损失往往与直接经济损失为同一量级,甚至是直接经济损失的数倍。间接经济损失评估是科学评价灾害影响不可或缺的组成部分,其中,产业部门间接经济损失和灾后恢复重建期的评估,可以为灾后恢复重建决策和防灾减灾规划提供有效的决策工具。政府决策者、学术界应重视灾害,特别是重大灾害(或巨灾)对地区经济长期可持续发展可能造成的影响,从而为减轻灾害的影响做好充分准备。     

洪水灾害遥感监测研究综述

洪水灾害是最严重的自然灾害之一,洪灾造成的损失十分严重,对其进行科学的监测是防灾减灾的基础。在洪水灾害遥感监测研究进展的介绍基础上,着重对中分辨率、高时相、微波、高精度DEM、多源数据遥感洪水监测原理及方法的研究进展进行比较和总结,分析各种数据特点。在此基础上提出了洪水遥感监测向高分辨率、高时相性方向,遥感影像相互订正和利用3S技术是洪涝灾害动态监测发展的方向,为洪水灾害的快速反应和防洪辅助决策提供依据。     

农村水污染的经济损失分析与评估——以邹城市北宿镇为例

介绍了目前常用的水污染经济损失基本评估法——分解求和方法及其具体模型(农业损失模型、畜牧业损失模型、渔业损失模型、人类健康损失模型)以及水污染经济损失的计量程序。以邹城市北宿镇为例,根据相关数据,分别计算了2010年农村水污染对当地农业、畜牧业、渔业和人类健康带来的损失。     

Evaluation of potential genotoxicity of five food dyes using the somatic mutation and recombination test

In this study, different concentrations of five food dyes (amaranth, patent blue, carminic acid, indigotine and erythrosine) have been evaluated for genotoxicity in the Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. Standard cross was used in the experiment. Larvae including two linked recessive wing hair mutations were chronically fed at different concentrations of the test compounds in standard Drosophila Instant Medium. Feeding ended with pupation of the surviving larvae. Wings of the emerging adult flies were scored for the presence of spots of mutant cells which can result from either somatic mutation or somatic recombination. For the evaluation of genotoxic effects, the frequencies of spots per wing in the treated series were compared to the control group, which was distilled water. The present study shows that carminic acid and indigotine demonstrated negative results while erythrosine demonstrated inconclusive results. In addition 25 mg mL⁻¹ concentration of patent blue and 12.5, 25 and 50 mg mL⁻¹ concentrations of amaranth demonstrated positive results in the SMART.     

洪水灾害风险评价研究综述

洪水灾害是当今世界最严重的自然灾害之一,带来了巨大的人员伤亡和经济损失。洪水灾害风险评价是科学有效地防洪减灾的前提和基础。文章对洪水灾害风险相关概念进行了界定,从气象、水文水力、社会经济、遥感与GIS和土地利用5个方面对洪水灾害风险评价的常用方法进行了评述,并列出了常用的评价因子。最后指出了未来研究的可能发展方向。     

Study on the Non-point Source Pollution in the Upper and Middle Reaches of the Taoer River Basin

The Taoer River basin is the epitome in the west of Northeast China and it is one of the most fragile and sensitive ecoregions. Thus, protection of water quality of the Taoer River is important. Not only point source pollution but non-point source (NPS) pollution results in deteriorating water quality. In this study, long-term hydrologic impact assessment model was used to evaluate the impacts of land use change impacts on NPS pollution, and the replacement cost method was used to calculate the economic loss caused by NPS pollution. Through analyzing the NPS pollutant loads of different land categories and the economic loss, the article puts forward that there exists a close relationship between land-use types and NPS pollution, and agricultural pollution is the main component of the NPS pollution in this area. The results of this study can provide decision-making basis for agricultural development and land-use change.     

中国环境污染损失测算及成因探析

环境问题备受关注,环境污染严重影响中国经济的增长质量.本文采用治理成本法测算了1989 -2008年中国环境污染造成的经济损失,利用环境污染经济损失数据,采用协整理论研究了中国环境污染损失与经济增长之间的关系.研究表明,我国经济总量与环境污染之间存在长期均衡关系,经济增长是造成环境污染的基础性原因,并且环境污染状况随经济增长仍有扩大的趋势,至今尚未出现环境库兹涅茨曲线拐点的迹象.然后,本文从产业结构、能源结构和效率角度揭示了环境污染的结构性成因.研究认为,高污染行业在整个国民经济中比重过大是造成环境污染的产业结构方面的成因;以煤炭为主的能源消费和高耗能产品增长过快是造成环境污染的能源结构成因;能源效率低下是造成环境污染的技术性成因;资源能源价格长期偏低和法律法规滞后是造成环境污染的制度性缺陷.最后,针对问题提出,只有切实转变经济增长方式,突出技术创新、健全市场机制、完善环境法规才是解决环境污染问题的根本出路.     

铁路隧道地下水环境动态监测体系的探讨与实践

铁路隧道排放地下水对隧道区域生态环境和人居环境的影响日益受到重视。在阐述监测等级、监测范围、监测对象和方法等的基础上,探讨了铁路隧道地下水环境动态监测体系,并在国内某货运铁路进行了系统实践。通过对48座隧道143处监控点位近3个水文年的系统监测,发现了34处隧道施工造成的失水水源点位;以典型隧道为例,总结说明黄土丘陵地区、基岩山区和岩溶地区监测结果,并讨论监测体系应用效果。