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681.
采用变化范围法(RVA)定量研究了丹江口水库蓄水后汉江中下游水文情势的时空变化,评估出汉江干流变化度最大的江段和水文特征指标类别,分析了其对应的生态影响,并针对汉江流域的四大家鱼和水华问题进行了敏感水文指标的变化度分析。结果显示:丹江口大坝蓄水后,汉江下游河道流量是中变化度占主导,比例范围为47~63%;水位是高变化度占主导,襄阳站和皇庄站高变化度的水文指标所占比例远大于其它站点,依次为53% 和75%,各站水位较蓄水前下降了1~2 m。黄家港站高/低流量脉冲出现的频率减少(变化度为-0.49和 -0.62),且持续的时间变短(变化度为-0.87和 -0.74)。皇庄站和襄阳站流量和水位的月均值和极值较蓄水前减少,逆转次数在高RVA范围内较蓄水前增加(变化度为1.82)。四大家鱼产卵的敏感水文指标出现频率较蓄水前减少,且为中高变化度。下游河道枯水期流量和水位减小,增加了水华发生几率。 相似文献
682.
长江上游大型水库群对宜昌站水文情势影响分析 总被引:1,自引:0,他引:1
近年来,长江上游已建成一批大型水库,其运行调度必然会对下游的径流产生影响。水文变化指标法(IHA)和水文变化幅度法(RVA)是以水流的量、时间、频率、延时和变化率5种基本特征为基础,对建坝前后的河道水文情势变化进行定量分析的方法。根据长江流域大型水库群建设的实际情况,利用Mann-Kendall秩次相关检验法划分了宜昌站建库前后的流量序列,用来评估长江上游大型水库群对宜昌站水文情势的改变情况。M-K相关检验发现,宜昌站的年最小流量已经在2000年发生了显著性地变化;IHA和RVA分析成果表明,宜昌站的水文情势已经发生了中等程度的改变,主要是与小流量相关的一些因子,如1~3月平均流量、最小流量六个因子、低脉冲发生次数及持续时间等;随着以三峡水库为核心的上游大型水库群建成并投入运行,未来长江下游河道径流还将发生进一步的改变。 相似文献
683.
P. Suresh S. Ramabalan U. Natarajan 《International Journal of Sustainable Engineering》2016,9(2):107-118
The recent developments in manufacturing organizations recognize sustainability as an important value addition for survival in the competitive scenario. The design engineers are in search of approaches for creating environmental conscious products. The purpose of this paper is to report a research carried out for ensuring sustainable product design by the integration of Design for Environment (DFE) and Design for Manufacture and Assembly (DFMA) methodologies. In this context, this paper reports a case study carried out in an automotive component. The candidate product is the charge alternator pulley. The existing pulley has been created using Computer Aided Design. Then sustainability analysis was conducted on the existing component for determining environmental impact. This is followed by the engineering analysis of the component using ANSYS. Then conceptual design changes were developed in the proposed product using DFMA concept. Then the environmental impact has been evaluated in terms of carbon footprint, energy consumption and air/water impacts on proposed product. It has been found that the optimized pulley design possesses minimal environmental impact. The result of the case study indicated that the integration of DFE and DFMA concept could initiate new developments in sustainable designs with minimal impact to the environment and it also reduces the product cost. 相似文献
684.
Amaral MJ Bicho RC Carretero MA Sanchez-Hernandez JC Faustino AM Soares AM Mann RM 《Chemosphere》2012,87(7):765-774
As part of a wider study examining the impacts of corn pesticides on lacertid lizards in north-western Portugal, we examined various physiological, biochemical, and histological biomarkers of exposure and effect among field populations of Podarcis bocagei. Biomarkers included body condition index, standard metabolic rate, locomotor performance, parasitization, glutathione oxidative pathways and related enzyme activity, lipid peroxidation and liver and testis histology. Few of the various biomarkers investigated provided statistically significant evidence of toxic effect. However, using a weight of evidence approach, we conclude that pesticides are affecting lizards living in the vicinity of pesticide exposed corn agriculture sites. Lizards from these locations present a profile of animals under metabolic stress with reduced condition indices, increased standard metabolic rate, lower incidence of hepatocyte vacuolation, altered iron metabolism, increased activation of GSH oxidation pathways, and even increased prevalence of hemoparasites. 相似文献
685.
686.
井喷失控点火时间与方位探讨 总被引:1,自引:0,他引:1
利用计算流体力学方法(CFD)对井喷失控后天然气扩散过程进行研究,在有限元基础上建立模型,采用κ-ε紊流模型求解得出井喷失控后可燃性蒸气云随时间、风速变化的影响情况,求出稳态以后易爆区域的蒸气云形状。取5.0%和15%作为甲烷的爆炸上、下限,在不同区域进行点火求解爆燃结果,通过比较给出推荐的点火时间和点火方位。该研究成果可对井喷失控蒸气云爆燃危害性进行预测,有助于指导井喷失控进行点火放喷工作,避免爆燃事故的发生。 相似文献
687.
Amajirionwu M Connaughton N McCann B Moles R Bartlett J O'Regan B 《Journal of environmental management》2008,88(4):1361-1372
Sustainable development indicators (SDIs) have emerged as a tool to measure progress towards sustainable development for a number of fields. However, no indicator initiative to date has been aimed at biosolids management at local authority, regional or national levels. This paper presents a study where stakeholders involved in the management of biosolids in Ireland participated in the development of SDIs for managing biosolids at the local/regional level. A significant 81% of participating stakeholders find SDIs either 'useful' or 'very useful' as a tool for managing biosolids. A suite of 22 indicators has been developed and arranged according to the driving force-pressure-state-impact-response (DPSIR) indicator framework. The indicators address all the domains of biosolids management namely, production, quality, cost, legislation/regulation, training/research and recycling/disposal. The stakeholder approach is recognition that no effective indicator set can be developed without the input of stakeholders. 相似文献
688.
三维可视化是描绘和理解模型的一种手段,是数据体的一种表征形式。环境监测数据是空间数据场,可实现三维可视化的科学表达。监测数据的表征,可结合相关环境要素共同还原场景,以直观形象地表达环境状况的空间分布特征。不同的监测数据具有不同的特征,可分别进行表征方式的设计。通过研究水体污染、大气污染、噪声污染等数据场的三维表征设计,探索了三维可视化在深度数据挖掘、说明环境问题等方面的应用价值。 相似文献
689.
Ex‐ante measures to improve risk preparedness for natural disasters are generally considered to be more effective than ex‐post measures. Nevertheless, most resources are allocated after an event in geographical areas that are vulnerable to natural disasters. This paper analyses the cost‐effectiveness of ex‐ante adaptation measures in the wake of earthquakes and provides an assessment of the future role of private and public agencies in disaster risk management. The study uses a simulation model approach to evaluate consumption losses after earthquakes under different scenarios of intervention. Particular attention is given to the role of activity diversification measures in enhancing disaster preparedness and the contributions of (targeted) microcredit and education programmes for reconstruction following a disaster. Whereas the former measures are far more cost‐effective, missing markets and perverse incentives tend to make ex‐post measures a preferred option, thus occasioning underinvestment in ex‐ante adaptation initiatives. 相似文献
690.
台风是一种导致严重灾害的天气系统,其灾害评估是减灾防灾的决策基础;国内外台风灾情评估基本区分为统计指标综合法和统计模拟法。归纳了6种主要的统计指标综合方法,总结了统计模拟评估法的基本步骤,在此基础比较了台风灾情评估方法的不同特点。从评估的模型、指标选择以及评估结果等几个方面评述了指标评估方法中以及统计模拟法存在的问题。最后,对灾情评估发展趋势的5个方面进行展望,并指出:国内统计模拟方法的评估较少开展,应与指标评估方法相结合,积极开展统计模拟方法的灾情评估;选择不同的行业,针对行业具体特点,建立敏感行业的灾情评估模型;加强高新技术,特别是卫星遥感技术在台风灾害评估中的应用;同时要加强评估决策支持系统研究。 相似文献