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41.
改进的灰色关联投影法在大气环境质量评价中的应用 总被引:1,自引:0,他引:1
大气环境质量评价具有多指标的特点,且各指标的属性、重要程度和可比性都不相同,使得方案比选具有明显的不确定性。通过采用适应不同环境的分辨系数和基于信息熵的权重计算,来改进灰色关联投影方法,使得大气环境质量评价更加客观、公正和准确。最后用实例论证该方法是有效可行的。 相似文献
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应用安全检查表、事故树、作业条件危险性分析等方法对露天小型采石场爆破作业进行了分析评价,找出了导致爆破作业事故发生的可能因素及可采用的预防途径,为小型露天爆破作业事故的预防提供有益参考. 相似文献
45.
首先对炼油厂的常压炉系统进行了火灾爆炸事故的FTA分析,在此基础上进行了深入的FMECA分析,绘制出分析表格,并提出将这两种方法结合起来应用的优点以及一般步骤.综合两种分析方法深入分析了引起火灾爆炸事故的原因,指出系统运行的潜在危险因素,根据分析结果提出综合性的安全改进和预防措施. 相似文献
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Reducing accident occurrence in petrochemical plants is crucial, thus appropriately allocating management resources to safety investment is a vital issue for corporate management as international competition intensifies. Understanding the priority of safety investment in a rational way helps achieve this objective.In this study, we targeted an acrylonitrile plant. First, Dow Chemical's Fire and Explosion Index (F&EI) identified the reaction process as having the greatest physical risk. We evaluated the severity of accidents in the reaction process using the Process Safety Metrics advocated by the Center for Chemical Process Safety (CCPS); however, this index does not express damages a company actually experience. To solve this problem, we proposed a new metric that adds indirect cost to CCPS metrics. We adopted fault tree analysis (FTA) as a risk assessment method. In identifying top events and basic events, we attempted to improve the completeness of risk identification by considering accidents from the past, actual plant operation and equipment characteristics, natural disasters, and cyber-attacks and terrorist attacks. Consequently, we identified the top events with high priority in handling because of serious accidents as fire/explosion outside the reactor, fire/explosion inside the reactor, and reactor destruction. The new CCPS evaluation index proposed in this study found that fire and explosion outside the reactor has the highest severity. We considered the creation of the fault tree (FT) diagram of the top event, estimating the occurrence probability, and identifying the risk reduction part and capital investment aimed at risk reduction. As an economically feasible selection method for risk reduction investment, using the difference in loss amounts before and after safety investments indicated investment priority. 相似文献
48.
Trace Element Concentrations and Bioindicator Responses in Tree Swallows from Northwestern Minnesota 总被引:5,自引:0,他引:5
Custer CM Custer TW Warburton D Hoffman DJ Bickham JW Matson CW 《Environmental monitoring and assessment》2006,118(1-3):247-266
Extremely high concentrations of cadmium (3.5 μg/g dry wgt.) and elevated concentrations of chromium (>10 μg/g dry wgt.) and mercury (1.6 μg/g dry wgt.) were reported in waterbird tissues at Agassiz National Wildlife Refuge in northwestern Minnesota in 1994. Tree
swallows (Tachycineta bicolor) were studied during 1998–2001 at three drainages into the Refuge, two pools on the Refuge, and at a nearby reference location
to document whether high levels of contaminants were still present, and if so to quantify the source and severity of the contamination.
Trace elements were measured in tree swallow eggs, livers, and diet. Reproductive success and bioindicator responses were
monitored. In 2000, water was drawn down on Agassiz Pool, one of the main pools on the Refuge. This presented an opportunity
to evaluate the response of trace element concentrations in the diet and tissues of tree swallows after reflooding. High concentrations
of trace elements were not detected in swallow tissues, nor were there differences among locations. Less than 20% of swallow
samples had detectable concentrations of cadmium or chromium. Mercury concentrations were low and averaged <0.25 μg/g dry wgt. in swallow tissues. Trace elements, including mercury, did not increase in tree swallows following the 2000 drawdown
at Agassiz Pool. Hatching success and survival of nestlings to 12 days-of-age for tree swallows on the Refuge were similar
to the national average and consistent with background trace element concentrations. Bioindicator measurements were within
the normal ranges as well. 相似文献
49.
Jim CY 《Environmental monitoring and assessment》2006,116(1-3):53-80
Urban trees serve important environmental, social and economic functions, but similar to other natural endowments they are
not customarily depicted in monetary terms. The needs to augment protection, funding and community support for urban greening
call for proper valuation. Heritage trees (HTs), the cream of urban-tree stock, deserve special attention. Existing assessment
methods do not give justice to outstanding trees in compact cities deficient in high-caliber greenery, and to their social-cultural-historical
importance. They artificially separate evaluation from valuation, which should be a natural progression from the former. Review
of tree valuation methods suggested the formula approach to be more suitable than contingent valuation and hedonic pricing,
and provided hints on their strengths and weaknesses. This study develops an alternative formulaic expert method (FEM) that
integrates evaluation and valuation, maximizes objectivity, broadly encompasses the key tree, tree-environment and tree-human
traits, and accords realistic monetary value to HTs. Six primary criteria (dimension, species, tree, condition, location,
and outstanding consideration) branched into 45 secondary criteria, each allocated numerical marks. Each primary criterion
was standardized to carry equal weight, and a tree's maximum aggregate score is capped at 100. A Monetary Assignment Factor
(MAF) to consign dollar value to each score unit was derived from three-year average per m2 sale price of medium-sized residential flats. The applicability of FEM was tested on selected HTs in compact Hong Kong. The
aggregate score of a tree multiplied by MAF yielded monetary value, which was on average 66 times higher than the result from
the commonly-adopted Council of Tree and Landscape Appraisers method. The computed tree values could be publicized together
with multiple tree benefits to raise understanding and awareness and rally support to protect HTs. The property-linked FEM
could be flexibly applied to other cities, especially to assess HTs in compact developing cities. 相似文献
50.
水环境系统脆弱性是水资源利用与生态环境研究的热点问题,通过研究水环境系统的内在机理,综合考虑影响水环境系统脆弱性的资源、环境、经济、社会等因素,借助驱动力-压力-状态-影响-响应-管理(DPSIRM)框架构建水环境系统脆弱性评价指标体系。在此基础上,构建基于变权灰色云模型的评价方法,对2004~2014年江苏省水环境系统脆弱性进行评价。结果表明:2004~2014年水环境系统脆弱性指数由47.056提高到63.210,脆弱性等级由“重度脆弱”演化为“中度脆弱”,并长期维持在“中度脆弱的”等级,2014年出现了向“轻度脆弱”状态转变的趋势。分析各个子系统对水环境系统脆弱性影响程度可知,影响子系统和响应子系统对江苏省水环境脆弱性系统的影响程度逐年增加;而压力子系统和管理子系统对水环境系统脆弱性的影响程度逐年下降;其它子系统对水环境系统脆弱性的影响维持在一定水平小幅度波动。 相似文献