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171.
A federal, state, and private partnership leveraged resources and employed a long‐term, systematic approach to improve aquatic habitat degraded by decades of intensive forest management in Finney Creek, a tributary to the Skagit River of Northwest Washington State. After more than a decade of work to reduce sediment sources and the risk of landslides within the watershed, log jam installation commenced in 1999 and progressed downstream through 2010. Log jam design was adapted as experience was gained. A total of 181 log jams, including 60 floating log ballasted jams, were constructed along 12 km of channel. The goal was to alter hydraulic processes that affect aquatic habitat formation along 39 km of stream with emphasis on 18.5 km of lower Finney Creek. Aquatic habitat surveys over a five‐year period show an increase in the area of large pools and an accompanying increase in residual and maximum pool depth in the lower river reach. Channel cross sections show a generally deeper channel at the log jams, better channel definition in the gravel deposits at the head of the log jams, and improved riffle and thalweg development below the log jams. Stream temperature in the upper river decreased by 1.0°F in the first three years, and 1.1°F in the lowest treated reach over nine years. There is a trend of less stream heating over the restoration time period. Photo points show that riparian vegetation is recolonizing gravel bars.  相似文献   
172.
Urine diversion (UD) has great potential to contribute to sustainably managing wastewater by separating urine at the source and recovering nutrients for reuse in agriculture. While factors enabling the UD technology in Sweden are thought to involve policies supporting nutrient recovery/reuse, on closer inspection, the variable success of UD systems has revealed that critical factors for success also relate to human-centred issues of social organisation, participation and incorporation of social knowledges of a variety of stakeholders into the decision-making process in which new technologies are trialled and adopted. Through the analytical lens of strategic niche management, we consider how early experimentation in UD has involved user participation and whether internal processes of learning, networking and visioning have been consciously considered and to what effect. As niche experiments are enabled/disabled not only by informal institutions such as values and social norms but also formal regulatory institutions, we have concurrently analysed the broader environment in which policies and institutions influence, to varying degrees, the uptake of UD.  相似文献   
173.
The European Union (EU) and member states alike are following a tradition of addressing fuel poverty and vulnerability at the point of purchase by final consumers by seeking to influence the impact of income, energy price and the built environment on the ability of household consumers to access the energy that they need. By focusing on the conditions of energy transmission in the most rapidly growing renewable electricity sector in the UK – offshore wind – this paper aims to question whether the regulatory socio-technological framing of renewable electricity transmission is reproducing conditions for fuel poverty and vulnerability in the UK. By drawing a comparison with renewable electricity transmission in Bulgaria, this paper argues that the problem might be symptomatic of the EU as a whole. While not arguing against the proliferation of renewable electricity and its importance in meeting the 2020 targets, this paper calls for expanding the scope of fuel poverty alleviation policy throughout the whole renewable electricity supply chain, building on Helm's argument that energy companies at the middle of the supply chain are better suited to deliver fuel policy.  相似文献   
174.
论环境治道变革   总被引:9,自引:0,他引:9  
环境政策型态是指环境政策采取的存在方式。根据我国环境政策的绩效表现和我国市场化改革的前景 ,我国环境政策应从“政府直控型环境政策”转向“社会制衡型环境政策” ,谓之“环境政策转型” ,主要途径是扩大社会环境权益 ,同时适当简化政府环境管理过程。为了进一步激励社会力量的环境保护行动 ,建议设立“环境权益保护日” ,并建立“全国环境保护协会”。  相似文献   
175.
通过变化应力比、预腐蚀时间、试验环境,开展2024-T62铝合金薄板长裂纹扩展试验。对试验结果进行处理与分析,给出腐蚀环境下2024-T62铝合金裂纹扩展Paris公式或Walker公式的材料常数,确定上述变化因素对2024-T62铝合金薄板长裂纹扩展速率的影响规律。  相似文献   
176.
雪冰中持久性有机污染物的研究进展   总被引:2,自引:0,他引:2  
雪冰是温带和极地生态系统中最重要的环境组份,它们不仅影响了能量平衡和水循环,而且也能直接影响当地、区域以及全球环境范围内的化学行为。降雪能很有效地从大气中清除颗粒和气相的POPs。本文简要介绍了雪冰环境中持久性有机污染物研究的科学意义,着重综述了POPs在极地和高海拔地区雪冰中的环境化学行为和雪冰中POPs的历史环境记录,并讨论了雪冰中POPs浓度的不确定性。持久性有机污染物从大气到冰川的过程并不容易理解,半挥发性有机化合物在沉积后的浓度存在不确定性。有机物沉积在积雪中后,随着积雪的老化和变形,它们能够随着融水迁移或者又挥发到大气中。全文最后对未来雪冰中POPs的研究需要进行了展望,并提出四点今后需加强研究的内容。由于青藏高原位于人类居住的低纬度高海拔地区,可能在POPs全球输送过程中起到重要的作用,今后需加强青藏高原地区雪冰中持久性有机污染物的研究;有机污染物在雪冰中主要是通过光化学反应进行转化,雪冰中有机污染物的光化学反应机理研究必须引起重视;随着雪冰样品前处理和分析测试技术的提高,将会推动雪冰中痕量POPs的环境变化记录研究的发展;通过建立模型模拟预算和评价POPs在积雪中的物理化学行为,也可以利用模型模拟POPs在老雪中的命运,确定其在融水中成比例蒸发和渗浸的速率。  相似文献   
177.
从经济发展背景与循环经济内涵入手,提出发展循环经济是多元资源型县域的现实选择。以辽宁省灯塔市为例,构建以循环型工业、循环型农业、循环型社会体系为主体的循环经济体系框架,并指出建立工业生态链、引入静脉产业和实现土地资源的有效循环利用是完善循环经济体系的必要内容。  相似文献   
178.
刘清坤  王君  李国强  马挺  梁凤来  刘如林 《环境科学》2008,29(12):3554-3560
从油田地层水中分离到1株嗜热解烃菌(地芽孢杆菌DM-2),通过研究该菌株在不同条件下降解原油的性能以及在最适条件下降解烃的特性发现:地芽孢杆菌DM-2可在45~70℃、pH 4.0~10.0、 0.2%~3.0%的盐离子浓度缺氧条件下降解原油烃类,其降解原油烃的最适温度和pH值分别为60℃和7.0.在此条件下,该菌可乳化液体石蜡作为碳源进行生长;气相色谱和红外光谱进一步分析表明,其能降解原油中的C14~C30的直链烷烃、支链烷烃和芳香烃类,并能降解C16~C36的长链单烷烃,其中对C28的降解量最高,达88.95%.DM-2菌株代谢烷烃的产物之一为脂肪酸,经液相色谱和质谱分析代谢十六烷产生的脂肪酸为乙酸,5 d产量达0.312 g/L,说明其采用次末端氧化途径氧化烷烃,之后进入β-氧化途径代谢.DM-2菌株在高温缺氧的极端环境下对烃的乳化、降解和产酸特性使其在高温石油污水的生物处理和开采重质原油方面具有潜在的应用价值.  相似文献   
179.
American Petroleum Institute (API) standards and recommended practices have identified inadvertent mixing of hot and cold liquids as a potential cause for equipment overpressure since 1955. The limited guidance has been informative but provides minimal if any details on conditions that could cause an overpressure and its potential severity. Therefore, the user must interpret how and when to prevent and/or mitigate the scenario. This guidance has changed little over the years. In June 2020, API published the 7th Edition of API Standard 521 which now provides specific guidance as to conditions whereby pressure relief devices can be considered for protection and conditions where prevention remains as the only recourse. This paper discusses the basis for the revised guidance in API Standard 521 and includes supplemental guidance.  相似文献   
180.
介绍了油气长输管道工程风险评价的国内外研究概况、进展、主要评价方法及存在的问题.  相似文献   
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