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871.
城市生活垃圾综合处理前分选系统设计   总被引:2,自引:0,他引:2  
本文以江油市城市生活垃圾处理厂为工程实例,介绍了垃圾前分选系统中的垃圾储料车间、行车与抓斗、垃圾上料机构、双层振动筛以及人工分选平台的工艺设计参数及设计依据,并在此基础上提出了该系统的改进建议.  相似文献   
872.
江苏省城市防汛决策支持系统研究   总被引:2,自引:2,他引:2  
刘俊  徐向阳 《灾害学》2002,17(4):11-15
在分析江苏省城市防汛问题的基础上,设计了其防汛决策支持系统;根据江苏省城市洪涝灾情特点研建和选用了适宜的数学模型,该模型可以迅速、可靠和正确地模拟城市雨情、水情、灾情的发展过程和可能后果,为城市防汛决策提供多层次的信息服务和多种支持手段。  相似文献   
873.
基于洪水灾害快速评估的承灾体易损性信息管理系统   总被引:5,自引:0,他引:5  
洪水灾害易损性信息管理系统是为了开展洪水灾害快速评估,对不同洪水灾害流域和同一洪水灾害流域中的不同地区、不同承灾体(财产分类)、不同致灾因子(水深和历时等)条件,以财产的损失率为核心的综合信息管理系统。本文介绍了洪水灾害易损性信息管理系统的开发与设计的基本原理,阐述了系统的总体结构框架和功能模块划分,并且在系统数据流程图的基础上,对损失率数据库等几个重要的模块进行了详细的分析与设计,给出了系统的部分运行结果。本系统在与GIS、遥感等空间技术结合后,能够高效地完成各种洪水灾害损失的快速评估与预测分析工作,同时,本系统亦可独立作为对区域洪水灾害易损性研究的数据基础和理论支撑。  相似文献   
874.
ABSTRACT: River Environment Classification (REC) is a new system for classifying river environments that is based on climate, topography, geology, and land cover factors that control spatial patterns in river ecosystems. REC builds on existing principles for environmental regionalization and introduces three specific additions to the “ecoregion” approach. First, the REC assumes that ecological patterns are dependent on a range of factors and associated landscape scale processes, some of which may show significant variation within an ecoregion. REC arranges the controlling factors in a hierarchy with each level defining the cause of ecological variation at a given characteristic scale. Second, REC assumes that ecological characteristics of rivers are responses to fluvial (i.e., hydrological and hydraulic) processes. Thus, REC uses a network of channels and associated watersheds to classify specific sections of river. When mapped, REC has the form of a linear mosaic in which classes change in the downstream direction as the integrated characteristics of the watershed change, producing longitudinal spatial patterns that are typical of river ecosystems. Third, REC assigns individual river sections to a class independently and objectively according to criteria that result in a geographically independent framework in which classes may show wide geographic dispersion rather than the geographically dependent schemes that result from the ecoregion approach. REC has been developed to provide a multiscale spatial framework for river management and has been used to map the rivers of New Zealand at a 1:50,000 mapping scale.  相似文献   
875.
ABSTRACT: Complex hydrologic models, designed for simulating larger watersheds, require a huge amount of input data. Most of these models use spatially distributed data as inputs. Spatial data can be aggregated or disaggregated for use as input to a model, which can impact model outputs. Although, it is efficient to minimize data redundancy by aggregating the spatial data, upscaling reduces the detail/resolution of input information and increases model uncertainty. On the other hand, a large number of model inputs with high degrees of disaggregation take more computer time and space to process. Hence, a balance between striving for a maximum level of aggregation and a minimum level of information loss has to be achieved. This study presents a definition of an appropriate level of discretization, derived by establishing a relationship between a model's efficiency and the number of subwater‐sheds modeled. An entropy based statistical approach/tool called Subwatershed Spatial Analysis Tool (SUSAT) was developed to find an objective choice of an appropriate level of discretization. The new approach/tool was applied to three watersheds, each representing different hydrologic conditions, using a hydrologic model. Coefficients of efficiency and entropy estimated at different levels of discretization were used to validate the success of the new approach.  相似文献   
876.
ABSTRACT: Over the last 20 years, our possibilities to model river flows numerically have increased enormously. In this paper, the question is addressed whether a more sophisticated model is always better than a simpler one. Increased detail, both in finer resolution and in physical processes taken into account, has its price in more computer time, higher data need, and perhaps more unknown coefficients to be calibrated. Moreover, uncertainty in actual physical conditions (e.g., bottom roughness), inflow and parameters remains, which may dominate the uncertainty of the results. Also, the questions asked by a decision maker may not always be very precise. For a schematic but relevant example, we show that a better model does not necessarily give more reliable results because some of the basic uncertainties remain. It is concluded that we should use the simplest model that will answer the question as to the accuracy needed, taking into account uncertainties in the data  相似文献   
877.
本建立了广西西北部喀斯特石山地区可持续发展的系统动力学模型。并用DYNAMO程序预测了未来20年桂西北地区的人口、工业、农业、第三产业,生态环境,土地资源,社会总产值,人均国民收人等的动态变化趋势,结果显示,该地区由于人口,工业资产增加使物质和能源消耗增长太快,而对污染治理的投入又太少,导致桂西北地区的生存环境质量下降,因此应当加大对污染治理的投入力度,改善区域环境质量,这是实现息烽县区域可持续发展的关键,根据区域特点探讨了桂西北喀斯特贫困山区的形成演化,提出了可持续发展的途径。  相似文献   
878.
本文论证了湖北稻区的资源具有三大特点。因此,认定该区应细分为:东南部早三熟双季稻区,中部单、双季稻两热三熟并存区,西北部单季稻两熟区。笔者认为,本区近10年发展麦稻、油稻稻、油稻减少肥稻稻、肥稻其主流是好的;讨论了紫云英大量减步后如何解决有机肥源匮乏的问题。主张今后应积极开发冬种,积极提倡冬作起厢分带间套,既稳定大宗作物的发展,又增产经作、饲料、蔬菜、绿肥,以提高稻田的经济效益。  相似文献   
879.
ABSTRACT: Landsat satellite Thematic Mapper (TM) data were used to assess regional soil moisture conditions. The mid-infrared (MIR) data of TM band 7 were overlain onto four principal land-use categories (Agricultural/Irrigated, Urban/Clearings, Forest/ Wetlands, Water) using a geographic information system (GIS). M data were used to assess four qualitative surface soil-moisture conditions (water/very wet, wet, moist, and dry) within each land-use category of a 208,354 ha southwestern Florida study area. The MIR response was inversely related to the qualitative surface soil-moisture content. Integration of Landsat TM MIR data with land use through GIS appears to be a useful technique for high-resolution regional soil moisture assessment, and further research to reline this technique is recommended.  相似文献   
880.
ABSTRACT: Techniques were developed using vector and raster data in a geographic information system (GIS) to define the spatial variability of watershed characteristics in the north-central Sierra Nevada of California and Nevada and to assist in computing model input parameters. The U.S. Geological Survey's Precipitation-Runoff Modeling System, a physically based, distributed-parameter watershed model, simulates runoff for a basin by partitioning a watershed into areas that each have a homogeneous hydrologic response to precipitation or snowmelt. These land units, known as hydrologic-response units (HRU's), are characterized according to physical properties, such as altitude, slope, aspect, land cover, soils, and geology, and climate patterns. Digital data were used to develop a GIS data base and HRIJ classification for the American River and Carson River basins. The following criteria are used in delineating HRU's: (1) Data layers are hydrologically significant and have a resolution appropriate to the watershed's natural spatial variability, (2) the technique for delineating HRU's accommodates different classification criteria and is reproducible, and (3) HRU's are not limited by hydrographic-subbasin boundaries. HRU's so defined are spatially noncontiguous. The result is an objective, efficient methodology for characterizing a watershed and for delineating HRU's. Also, digital data can be analyzed and transformed to assist in defining parameters and in calibrating the model.  相似文献   
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