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排序方式: 共有1295条查询结果,搜索用时 281 毫秒
741.
Ljerka Kratofil Krehula Zlata Hrnjak-Murgić Jasenka Jelenčić Branka Andričić 《Journal of Polymers and the Environment》2009,17(1):20-27
Poly (ethylene-terephthalate), (PET) bottles waste was chemically recycled by glycolysis and hydrolysis. The depolymerization
processes were carried out in different time intervals from 5 to 360 min, in two different molar ratios of PET/EG, 1:5 and
1:18 and at different temperatures. The PET glycolysis leads to formation of bis(2-hydroxy-ethyl)terephthalate (BHET) monomer
and PET oligomers with hydroxyl and carboxyl end groups while PET hydrolysis is followed by formation of monomers terephthalic
acid (TPA) and ethylene glycol (EG). Fractions of monomers and oligomers were further characterized by FTIR spectroscopy and
by differential scanning calorimetry (DSC). The results show that DSC is successful method to describe the different structures
of oligomers formed during chemical recycling of PET. 相似文献
742.
氧化亚铁硫杆菌的筛选、生长特性及其橡胶再生研究 总被引:3,自引:0,他引:3
从大西洋底死火山口土壤中筛选出一株硫杆菌,经16S rDNA鉴定为氧化亚铁硫杆菌。研究了初始底物Fe2+浓度,初始pH,接种量对其生长的影响,确定了其最佳的生长的条件:在30℃、170 r/min条件下,最适底物Fe2+浓度为9 g/L,最佳初始pH为2.5,最适接种量为10%(体积分数)。探讨了氧化亚铁硫杆菌对天然硫化橡胶的脱硫再生,橡胶的SEM分析、FTIR图谱及EDS图谱研究表明氧化亚铁硫杆菌对硫化胶粉的硫交联键有断裂或转化作用,脱硫率达52.6%,氧化亚铁硫杆菌对天然橡胶具有一定的再生作用。 相似文献
743.
Srivastava SK 《Disasters》2009,33(1):58-81
The right mix of policy, institutional arrangements and use of technology provides the framework for a country's approach to disaster mitigation. Worldwide, there has been a shift away from a strictly 'top-down' approach relying on government alone, to a combination of 'top-down' and 'bottom-up' approaches. The aim is to enhance the indigenous coping mechanisms of vulnerable communities; draw on their cooperative spirit and energy; and empower them through appropriate information and contextual knowledge to mitigate natural disasters. In light of this, the paper examines India's use of space technology in its disaster management efforts. Poverty alleviation and disaster management are almost inseparable in many parts of the country, as vulnerability to natural disasters is closely aligned with poverty. Addressing these issues together requires integrated knowledge systems. The paper examines how knowledge inputs from space technology have strengthened the national resolve to combat natural disasters in conjunction with alleviating rural poverty. 相似文献
744.
A GIS Framework for Regional Modeling of Riverine Nitrogen Transport: Case Study,San Antonio and Guadalupe Basins
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Ahmad A. Tavakoly David R. Maidment James W. McClelland Tim Whiteaker Zong‐Liang Yang Claire Griffin Cédric H. David Lisa Meyer 《Journal of the American Water Resources Association》2016,52(1):1-15
This article presents a framework for integrating a regional geographic information system (GIS)‐based nitrogen dataset (Texas Anthropogenic Nitrogen Dataset, TX‐ANB) and a GIS‐based river routing model (Routing Application for Parallel computation of Discharge) to simulate steady‐state riverine total nitrogen (TN) transport in river networks containing thousands of reaches. A two‐year case study was conducted in the San Antonio and Guadalupe basins during dry and wet years (2008 and 2009, respectively). This article investigates TN export in urbanized (San Antonio) vs. rural (Guadalupe) drainage basins and considers the effect of reservoirs on TN transport. Simulated TN export values are within 10 percent of measured export values for selected stations in 2008 and 2009. Results show that in both years the San Antonio basin contributed a larger quantity than the Guadalupe basin of delivered TN to the coastal ocean. The San Antonio basin is affected by urban activities including point sources, associated with the city of San Antonio, in addition to greater agricultural activities. The Guadalupe basin lacks major metropolitan areas and is dominated by rangeland, rather than fertilized agricultural fields. Both basins delivered more TN to coastal waters in 2009 than in 2008. Furthermore, TN removal in the San Antonio and Guadalupe basins is inversely related to stream orders: the higher the order the more TN delivery (or the less TN removal). 相似文献
745.
Sissel Hovik 《Journal of Environmental Policy & Planning》2016,18(4):535-555
To handle the challenge of complex cross-sector and multilevel coordination in the implementation of the European Union Water Framework Directive, Norway has established multilevel governance networks. Observers have pointed to a risk of such governance arrangements being dominated by experts. This article studies the highly complex multilevel governance networks of water management in Norway, and unveils the importance of political anchorage of such governance networks at local and regional levels. The study finds evidence that political anchorage matters for further network achievements. Because the water governance networks are subordinated to the hierarchy of government, they need to ‘talk to' the system of hierarchical government in order to be effective. In this regard, it seems crucial that networks are politically anchored. Furthermore, the study unveils the important role of political leadership and network managers in ensuring political anchorage. 相似文献
746.
The aim of this qualitative research was to examine the dynamics of existing and emerging social networks among Latino survivors of Hurricane Katrina. Data were generated through individual, in-depth interviews conducted with 65 Latinos within six months of the storm striking the Gulf Coast of the United States in August 2005. The findings illustrated both the role of social networks in gathering information, making decisions and accessing resources, and how these existing social networks were disrupted and strained by overwhelming needs. Broader structural issues, including poverty and a lack of transportation, combined with marginalised status as immigrants, further constrained access to essential information and resources. In response, new, if temporary, social networks emerged, based primarily on shared nationality, language, and a sense of collective commitment. Practice implications include the need to consider the social network dynamics of marginalised groups in developing innovative strategies to overcome structural barriers to accessing resources essential for disaster preparedness and survival. 相似文献
747.
Coordination theory provides a theoretical framework for analysing complex processes of project groups working towards a common goal. In this study, we explore the relationship between coordination and social networks for the development of a network-based coordination model. This model is applied to measure the performance and quality of complex and dynamic project coordination such as in hospital emergency departments. The dataset used for the study was collected by the 2004 National Hospital Ambulatory Medical Care Survey--a national probability sample survey of visits to emergency and outpatient departments of non-Federal, short-stay and general hospitals in the United States. Using social network analysis, this study allows us to understand the possible causes of inefficient coordination performance and coordination quality resulting in access blocks. 相似文献
748.
为了解城市地震次生灾害的演化路径及扩散机理,进而为城市防震救灾工作提供科学的参考依据,通过对城市地震有关资料和文献的分析,确定出城市地震次生灾害演化系统贝叶斯网络的节点变量及取值范围,并根据节点变量之间的因果关系构建出贝叶斯网络结构图。通过对国内外典型震例中的16个受灾城市相关数据进行统计,分析获得网络结构各个变量的条件概率。结合贝叶斯网络推理知识,利用贝叶斯网络工具箱分析了在相同的地震输入变量、不同的控制输入变量取值条件下,各类城市地震次生灾害的发生概率。算例分析结果表明不同的应急管理水平对城市地震各类次生灾害的发生概率有显著影响。 相似文献
749.
简述了国内大部分焦化厂目前采用的焦化废水处理组合工艺存在的问题,介绍了高浓度(未稀释)焦化废水处理的技术原理及工艺特点,结合工程应用实例,指出高浓度焦化废水处理及再生回用技术具有广阔的推广应用前景。 相似文献
750.