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31.
Predicting environmental impacts is essential when performing an environmental assessment on urban transport planning. System dynamics (SD) is usually used to solve complex nonlinear problems. In this study, we utilized system dynamics (SD) to evaluate the environmental impacts associated with urban transport planning in Jilin City, China with respect to the local economy, society, transport, the environment and resources. To accomplish this, we generated simulation models comprising interrelated subsystems designed to utilize changes in the economy, society, road construction, changes in the number of vehicles, the capacity of the road network capacity, nitrogen oxides emission, traffic noise, land used for road construction and fuel consumption associated with traffic to estimate dynamic trends in the environmental impacts associated with Jilin's transport planning. Two simulation scenarios were then analyzed comparatively. The results of this study indicated that implementation of Jilin transport planning would improve the current urban traffic conditions and boost the local economy and development while benefiting the environment in Jilin City. In addition, comparative analysis of the two scenarios provided additional information that can be used to aid in scientific decision-making regarding which aspects of the transport planning to implement in Jilin City. This study demonstrates that our application of the SD method, which is referred to as the Strategic Environmental Assessment (SEA), is feasible for use in urban transport planning.  相似文献   
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ABSTRACT: Twenty-two gaging stations were selected for developing a regional flood frequency curve for small (area less than 2 square miles) watersheds in southern Illinois. Five probability functions were compared, and the extreme value type I function was selected to develop the regional flood curve. The curve was generated with the index flood method and also another empirical method that related the function parameters to the watershed area. Estimated peak discharges with various return periods were compared with the results obtained from multiple regression analysis.  相似文献   
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The Klang River Basin is located in the most densely populated region in Malaysia, with its heavy concentration of industries and population. A systematic study of the pollution to this river system caused by phenolic compounds have been carried out under this project. Analyses of water samples from the Klang River by high performance liquid chromatography (HPLC) with an ultraviolet (UV) detector at 280 nm have shown the presence of some priority phenolic pollutants.  相似文献   
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Disturbance plays an important role in structuring marine ecosystems, and there is a need to understand how conservation practices, such as the designation of Marine Protected Areas (MPAs), facilitate postdisturbance recovery. We evaluated the association of MPAs, herbivorous fish biomass, substrate type, postdisturbance coral cover, and change in macroalgal cover with coral recovery on the fringing reefs of the inner Seychelle islands, where coral mortality after a 1998 bleaching event was extensive. We visually estimated benthic cover and fish biomass at 9 sites in MPAs where fishing is banned and at 12 sites where fishing is permitted in 1994, 2005, 2008, and 2011. We used analysis of variance to examine spatial and temporal variations in coral cover and generalized additive models to identify relations between coral recovery and the aforementioned factors that may promote recovery. Coral recovery occurred on all substrate types, but it was highly variable among sites and times. Between 2005 and 2011 the increase in coral cover averaged 1%/year across 21 sites, and the maximum increase was 4%/year. However, mean coral cover across the study area (14%) remained at half of 1994 levels (28%). Sites within MPAs had faster rates of coral recovery than sites in fished areas only where cover of macroalgae was low and had not increased over time. In MPAs where macroalgae cover expanded since 1998 there was no recovery. Where coral was recovering on granite reefs there was a shift in relative prevalence of colony life‐form from branching to encrusting species. This simplification of reef structure may affect associated reef fauna even if predisturbance levels of coral cover are attained. Efecto de la Expansión de Macroalgas y Áreas Marinas Protegidas sobre la Recuperación de Coral Después de una Perturbación Climática  相似文献   
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萍乡市农用土壤重金属含量及其分布特征分析   总被引:1,自引:0,他引:1  
以江西省萍乡地区农用土壤为研究对象,分析研究了萍乡市农用土壤中重金属的含量、分布特征。结果表明:萍乡地区农用土壤中重金属的平均含量均未超过国家土壤环境质量二级标准,但其中锌、镍、铬、铜、镉、砷、铅、锰、汞的含量均超过了江西省土壤重金属相应元素的背景值。从空间分布来看,在全市5个县区布置的29个测点中,有14个测点的重金属含量超标;其中上栗县有8个测点超标,明显多于其他县区,出现了不同的污染特征。  相似文献   
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Nutrient salts present in liquid by-products following waste treatment are lost resources if not effectively recycled, and can cause environmental problems if improperly disposed. This research compared the growth response and mineral nutrient status of two nursery and two turfgrass species, hydroponically supplied with nutritive by-product extracts derived from anaerobically digested municipal solid waste (MSW) and aerobically composted organic wastes from the mushroom and MSW industries. Forsythia (Forsythia x intermedia 'Lynwood') and weigela (Weigela florida 'Red Prince'), and creeping bentgrass (Agrostis palustris Huds.) and Kentucky bluegrass (Poa pratensis L.), were grown in nutrient solutions/extracts prepared from: (i) half-strength Hoagland's #2 solution (HH; control), (ii) Plant Products liquid fertilizer (PP; g kg(-1): 180 N; 39 P; 224 K), (iii) spent mushroom compost (SMC), (iv) MSW compost (GMC), and (v) intra-process wastewater from the anaerobic digestion of MSW (ADW). Additional nutrient solutions (SMC-A, GMC-A, and ADW-A) were prepared by amending the original solutions with N, P, and/or K to concentrations in HH (mg L(-1): 105 N; 15 P; 118 K). Plants receiving the SMC-A extract grew best or at least as well as those in HH, PP, and the amended GMC-A and ADW-A solutions. This study indicated that, with proper amendments of N, P, K and other nutrients, water-soluble constituents derived from organic waste treatment have potential for use as supplemental nutrient sources for plant production.  相似文献   
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基于多孔介质力学建立非饱和土在冻结过程中的耦合方程并进行单向冻融过程的数值求解及模拟分析。把非饱和冻土当作固体土颗粒、未冻水、冰晶及孔隙气组成的多孔多相介质,在小变形假定下建立了考虑冰?水、水?水汽相变的非饱和冻土的质量守恒、动量守恒方程,以及能量方程、耗散不等式、热平衡方程。结合冻融过程中的渗透特性以及应力应变关系,对单向冻融条件下的非饱和土柱封闭系统进行了数值求解,计算结果表明冷端冻结温度的数值对非饱和土柱的顶部位移影响较大,而对温度场的分布规律以及冻结区的含水率分布影响较小。研究结果可为寒区非饱和土工程的设计和施工提供指导。  相似文献   
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