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701.
ABSTRACT: The Basin Characteristics System (BCS) has been developed to quantify characteristics of a drainage basin. The first of four main BCS processing steps creates four geographic information system (GIS) digital maps representing the drainage divide, the drainage network, elevation contours, and the basin length. The drainage divide and basin length are manually digitized from 1:250,000-scale topographic maps. The drainage network is extracted using GIS software from 1:100,000-scale digital line graph data. The elevation contours are generated using GIS software from 1:250,000-scale digital elevation model data. The second and third steps use software developed to assign attributes to specific features in three of the four digital maps and analyze the four maps to quantify 24 morphometric basin characteristics. The fourth step quantifies two climatic characteristics from digitized State maps of precipitation data. Compared to manual methods of measurement, the BCS provides a reduction in the time required to quantify the 26 basin characteristics. Comparison tests indicate the BCS measurements are not significantly different from manual topographic-map measurements for 11 of 12 primary drainage-basin characteristics. Tests indicate the BCS significantly underestimates basin slope. Comparison-measurement differences for basin slope, main channel slope, and basin relief appear to be due to limitations in the digital elevation model data.  相似文献   
702.
本文介绍了Cu-CNS-HSCH_2COOH底液测定废水中微量铜的新方法,该法灵敏度较高,选择性较好,抗干扰强,简便、快速,与8羟基喹啉-铜络合物吸附波法对照,结果满意.  相似文献   
703.
Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments. This is paper IX in D. J. Schaeffer's “Environmental Audit” series.  相似文献   
704.
人工神经网络在沿海区域环境复杂系统预测中的应用   总被引:6,自引:0,他引:6  
针对复杂系统的非线性特征,分析了应用人工神经网络技术实现可持续发展复杂系统预测的可能性,并以上海市和崇明县为例建立沿海区域预测模型,取得了较好的预测结果,为可持续发展复杂系统的预测研究探索了一种新的可能方法。  相似文献   
705.
在为用挤压工艺生产快门壳而进行的工艺试验中,为了控制这种复杂多台阶空心零件复合挤压正、反挤方向的变形量,采用了改变润滑条件和凹模圆角的工艺措施,得到了预期的效果.从而为确定类似空心零件挤压生产工艺参数提供了一种简便而行之有效的方法.  相似文献   
706.
基于地理标志农产品种植户的实地调研数据,利用多元线性回归模型从生计维度研究种植户对猕猴桃物候期内气象灾害的感知及适应策略的影响因素。物候期内气象灾害的感知对种植户适应能力有显著影响。不同类别生计资本对于种植户采取适应策略的影响具有差异性:自然资本通过提升家庭生计基础显著影响种植户采取越冬期冻害、芽膨大期冻害适应策略;物质资本通过改善家庭生产物资形式影响种植户采取越冬期冻害适应策略;金融资本通过拓宽家庭金融收入渠道等方式显著影响种植户采取越冬期冻害、芽膨大期冻害、高温日灼灾害适应策略;社会资本通过丰富家庭同质性和异质性社会资本显著影响种植户采取夏季干旱适应策略;人力资本则通过提升家庭整体教育质量并推动再生产能力显著影响种植户采取芽膨大期冻害与秋季连阴雨适应策略。最后,建议政府应通过提升种植户获取气象信息能力、加强举办农业培训等技能学习活动、完善农业组织建设等措施以提升其适应能力。  相似文献   
707.
面向国土空间规划的“双评价”:抗解问题与有限理性   总被引:3,自引:3,他引:0  
资源环境承载能力和国土空间开发适宜性评价(即“双评价”)被视为国土空间规划编制的科学基础和约束条件。通过分析和总结当前国土空间规划编制中开展的“双评价”工作,发现“双评价”在发挥积极作用的同时,仍然存在对影响资源环境承载力能力和国土空间开发适宜性的科学机理认识不足、评价技术方法不完善、应用制度不健全等问题。未来需要面向生态文明理念下国土空间规划的现实需求,完善“双评价”的科学逻辑、技术逻辑和应用逻辑,提升“双评价”的科学性和实用性。同时,也应认识到国土空间规划本质上是个抗解问题,“双评价”只能发挥有限理性作用,应重视通过沟通交流、公众参与等方式应对国土空间规划编制中的具体问题,避免陷入技术决定论的误区。  相似文献   
708.
本文首先对大型复杂电子系统的特点及"五性"一体化设计的思想进行了阐述,进而结合工程实际,分析了当前"五性"设计存在的问题,提出开展"五性"一体化设计是解决上述问题的根本出路,并提出了相应建议措施,对如何建立"五性"指标体系、综合设计模型、"五性"一体化信息平台进行了一定的阐述。  相似文献   
709.
The impact of the management of packaging waste on the environment, economic growth and job creation is analyzed in this paper. This integrated assessment intends to cover a gap in the literature for this type of studies, using the specific case study of the Portuguese packaging waste management system (SIGRE).The net environmental benefits associated with the management of packaging waste, are calculated using the Life Cycle Assessment methodology. The results show that, for the categories studied, the impacts associated to SIGRE's various activities are surpassed by the benefits associated to material and energy recovery, with special focus on recycling. For example, in 2011 SIGRE avoided the emission of 116 kt CO2 equiv. – the equivalent carbon emission of the electricity consumption of 124.000 households in Portugal.The economic impact of SIGRE is evaluated through Input–Output Analysis. It was found that SIGRE's activities also have a significant economic impact. For example, their added value are ranked amongst the upper third of the economic activities with highest multiplier effect at national level: this means that for each Euro of value added generated within SIGRE, 1.25 additional € are added to the rest of the economy (multiplier effect of 2.25).Regarding the social impacts of SIGRE, the number of direct jobs associated with the system is estimated to be more than two thousand and three hundred workers. Out of these, 83% are connected to the management of municipal waste packaging (selective collection and sorting), 15% are connected to the management of non-municipal packaging waste and only 2% are connected to the Sociedade Ponto Verde (SPV, green dot society in English) – the management entity responsible for SIGRE.In general terms, the results obtained provide quantitative support to the EEA (2011) suggestion that moving up the waste hierarchy – from landfilling to recycling – creates jobs and boosts the economy.  相似文献   
710.
This paper proposes an optimization-based approach for designing rainwater harvesting systems for domestic use in a residential development. The optimization model accounts for the implementation of rainwater harvesting devices, pipes and reservoirs for the optimal sitting, collecting, storing and distribution of harvested rainwater. The optimization model consists in satisfying the water domestic demands and considers as objective function the minimization of the total annual cost associated to the fresh water, the capital costs for the catchment areas, storages and pumps, and the cost associated to the pumping, maintenance and treatment. A case study for a residential development in Morelia, Mexico is presented. The city of Morelia is characterized for having complications to satisfy the water demands, especially during dry seasons. The application of the proposed optimization approach shows that it is possible to satisfy a significant percentage of the domestic water demands using a harvesting rainwater system decreasing the associated cost in the time horizon. Several scenarios have been presented to show the potential solutions identified in the case study.  相似文献   
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