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421.
The paper reviews large scale experiments with various fuels in air where successful deflagration to detonation transition (DDT) took place. This includes a recent experiment disclosed in the Buncefield R&D program, where DDT developed in the propane/air mixture. The DDT occurred in branches of deciduous trees in a premixed stagnant mixture. An internal R&D investigation programme was initiated to better understand the phenomena. A large scale experiment in an open space with ethane air mixture is presented in the paper. The premixed mixture was ignited at the edge of the congested three-dimensional rigs which consisted of vertical and horizontal pipes. After ignition, the flame accelerated in the congestion and transitioned to detonation at the end of congestion. Stable detonation propagated through the remaining open and uncongested space.The flame acceleration process leading to DDT is scale dependent. It also depends on many parameters leading to a large investigation array and, significant cost. However, such R&D efforts aimed toward a safer plant design, i.e. the prevention of occurrence of a major accident, are a small fraction of a real accident cost.  相似文献   
422.
This paper reviews key challenges and opportunities addressed by the New York City Environmental Justice Alliance's (NYC-EJA) Waterfront Justice Project, a citywide campaign to promote climate resilience and sustainability in urban industrial waterfront communities of New York City. NYC-EJA is a non-profit membership-driven network linking grassroots organisations from low-income neighbourhoods and communities of colour in their struggle for environmental justice. The Waterfront Justice Project is documenting community vulnerability in the context of climate change impacts, sources of industrial pollution, and demographic and socio-economic trends. This campaign is enabling community-based organisations, environmental justice communities, city planners, local and state government agencies, local business-owners, and other stakeholders to work in partnership to achieve community resilience while advocating for local jobs and promoting best practices in pollution prevention. New York City's waterfront policies ease the siting and clustering of public infrastructure, water pollution control plants, waste transfer stations, energy facilities, and heavy manufacturing uses in six areas designated as Significant Maritime and Industrial Areas (SMIAs). The SMIAs are located in environmental justice communities, largely low-income communities and communities of colour, in the South Bronx, Brooklyn, Queens, and Staten Island. New York City's local waterfront land use and zoning policies create cumulative risk exposure not only to residents and workers in the host waterfront communities, but also, in the event of storm surge or sea-level rise, to neighbouring, upland communities.  相似文献   
423.
Yi Lu  Jiuping Xu 《Disasters》2015,39(2):258-278
The number of communities affected by disasters has been rising. As a result, non‐governmental organisations (NGOs) that attend community post‐disaster reconstruction are often unable to deliver all requirements and have to develop cooperative approaches. However, this collaboration can cause problems because of the complex environments, the fight for limited resources and uncoordinated management, all of which result in poor service delivery to the communities, adding to their woes. From extensive field research and case studies conducted in the post‐Wenchuan earthquake‐stricken communities, this paper introduces an integrated collaboration framework for community post‐disaster reconstruction with the focus on three types of NGOs: international, government organised and civil. The proposed collaboration framework examines the three interrelated components of organisational structure, operational processes and reconstruction goals/implementation areas. Of great significance in better promoting collaborative participation between NGOs are the crucial concepts of participatory reconstruction, double‐layer collaborative networks, and circular review and revision.  相似文献   
424.
紫色土丘陵坡地土壤微生物群落的季节变化   总被引:1,自引:0,他引:1  
采用稀释平板法和Biolog-ECO微平板技术,以剌槐(Robinia pseudoacacia)天然次生林为研究对象,研究湖南省衡阳市紫色土丘陵坡地表层(0~10 cm)土壤微生物群落的季节变化特征。结果表明:1)夏季,土壤微生物总数,细菌数量、真菌数量和放线菌数量最高,分别为16.34×106、16.09×106、10.43×104和14.64×104 cfu·g-1干土,春季次之:11.61×106、11.45×106、5.00×104和10.65×104 cfu·g-1干土,秋季最低:5.87×106、5.78×106、4.67×104和4.08×104 cfu·g-1干土,春、夏和秋3季的差异达显著水平(P<0.05);2)在培养168 h时,土壤微生物C源平均颜色变化率(Average well color development, AWCD)以夏季最高(1.20),春季次之(0.88),秋季最低(0.83);3)土壤微生物功能多样性表现为夏季明显高于春、秋2季(P<0.05),夏季的Patrick丰富度指数(R)(28)、Shannon-Wiener指数(H)(3.22)、Simpson指数(D)(0.96)和McIntosh指数(U)(8.20)显著高于春、秋2季(P<0.05),而春、秋2季的R(23,24)、H(3.06,3.08)、D(0.95,0.95)和U(5.90,5.91)无显著差异(P>0.05);4)氨基酸类、聚合物类和羧酸C源类是衡阳紫色土丘陵坡地土壤微生物偏好且利用率较高的C源类型;5)主成分分析表明,土壤微生物群落的C源利用可分为2类,一类在夏季,另一类在春、秋2季,其得分系数的分布范围分别为(2.59~6.00,2.43~5.09)和(-7.65~-1.90,-6.38~-3.43)。研究结果为科学评价湖南省衡阳市紫色土丘陵坡地土壤生境质量退化和恢复过程中微生物特征的变化提供了本底值参考。  相似文献   
425.
Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR CR CSR system and E2 EE2 BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation.  相似文献   
426.
Based on the texts of 1.3 million blog posts and the structure of the links between the blogs in which these posts appeared, this study presents an analysis of the discourse on climate change in the English-language blogosphere. Our approach combines community detection with probabilistic topic modeling to show how topics related to climate change are discussed across various parts of the blogosphere. We find that there is one community of predominantly climate skeptical blogs but several accepter communities. The topic analysis reveals a series of issues that are characteristic of the climate change discourse in the blogosphere. Two topics, one related to climate change science and one related to climate change politics, are particularly important for characterizing the discourse. We also find that the distribution of topics over the communities cuts across the divide between skeptics and non-skeptics (accepters) and that there are differences in the patterns of interactions between the skeptics and different groups of accepters.  相似文献   
427.
于2014年10月至2015年1月采用样线调查法对黄河三角洲自然保护区秋季迁徙期和越冬期水鸟群落结构进行调查研究,调查共包括8条样线40个观测点.结果表明:(1)秋季迁徙期共记录水鸟6目14科54种,国家Ⅰ级保护鸟类5种,国家Ⅱ级保护鸟类8种;越冬期共记录水鸟5目7科31种,国家Ⅰ级保护鸟类1种,国家Ⅱ级保护鸟类4种.(2)2个时期雁形目水鸟种类和数量均占优势,豆雁(Anser fabalis)、斑嘴鸭(Anas poecilorhycha)、赤膀鸭(Anas strepera)和绿头鸭(Anas platyrhynchos)为优势物种,丹顶鹤(Grus japonensis)、东方白鹳(Ciconia boyciana)和大大鹅(Cygnus cygnus)等珍稀水鸟也有一定的种群数量.(3)秋季迁徙期水鸟种数、数量和ShannonWiener多样性指数多于或高于越冬期.(4)5种典型生境之间水鸟种类和数量存在差异,天然水域是水鸟群落的主要分布区.(5)自然生境内的水鸟种数、数量和Shannon-Wiener多样性指数一般多于或高于人工生境.相似性分析结果表明,自然生境之间水鸟群落结构相似程度高于人工生境.  相似文献   
428.
In the field of disaster management, not many have considered the role and needs of people with disabilities despite their number and condition. The purpose of this paper is to push for specific inclusion of people with disabilities, their needs and participation, into disaster management by studying relevant cases from Indonesia, Korea, and the USA. Qualitative content analysis was used as a major methodology by comparing three factors identified in these nations: government policies, schools and advocacy groups’ efforts, and families and local communities’ awareness. Three models, one from each country, were considered major takeaways from this study: the Indonesian moral inclusion, the Korean medical treatment without exclusion, and the US’ extending social inclusion. In addressing the needs and participation of people with disabilities in disaster management, the following recommendations are put forward: for Indonesia, a move away from olden beliefs and misconceptions on disability (e.g. as a punishment) is imperative. In Korea, relevant fundamental laws (e.g. the Basic Act on Emergency and Safety Management) need to be revised while also studying advanced laws on the subject. For the USA, though the country is already advanced, overall improvement is still needed in terms of association with international non-governmental organizations, increase in the number of (emergency or disaster) response officials, and provision of better medical treatment.  相似文献   
429.
The integrated project "AquaTerra" with the full title "integrated modeling of the river-sediment-soil-groundwater system; advanced tools for the management of catchment areas and river basins in the context of global change" is among the first environmental projects within the sixth Framework Program of the European Union. Commencing in June 2004, it brought together a multidisciplinary team of 45 partner organizations from 12 EU countries, Romania, Switzerland, Serbia and Montenegro. AquaTerra is an ambitious project with the primary objective of laying the foundations for a better understanding of the behavior of environmental pollutants and their fluxes in the soil-sediment-water system with respect to climate and land use changes. The project performs research as well as modeling on river-sediment-soil-groundwater systems through quantification of deposition, sorption and turnover rates and the development of numerical models to reveal fluxes and trends in soil and sediment functioning. Scales ranging from the laboratory to river basins are addressed with the potential to provide improved river basin management, enhanced soil and groundwater monitoring as well as the early identification and forecasting of impacts on water quantity and quality. Study areas are the catchments of the Ebro, Meuse, Elbe and Danube Rivers and the Brévilles Spring. Here we outline the general structure of the project and the activities conducted within eleven existing sub-projects of AquaTerra.  相似文献   
430.
Sampling of a population is frequently required to understand trends and patterns in natural resource management because financial and time constraints preclude a complete census. A rigorous probability-based survey design specifies where to sample so that inferences from the sample apply to the entire population. Probability survey designs should be used in natural resource and environmental management situations because they provide the mathematical foundation for statistical inference. Development of long-term monitoring designs demand survey designs that achieve statistical rigor and are efficient but remain flexible to inevitable logistical or practical constraints during field data collection. Here we describe an approach to probability-based survey design, called the Reversed Randomized Quadrant-Recursive Raster, based on the concept of spatially balanced sampling and implemented in a geographic information system. This provides environmental managers a practical tool to generate flexible and efficient survey designs for natural resource applications. Factors commonly used to modify sampling intensity, such as categories, gradients, or accessibility, can be readily incorporated into the spatially balanced sample design.  相似文献   
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