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501.
Mohamed El Alaoui 《International Journal of Green Energy》2020,17(11):644-651
ABSTRACT The energy consumed around the world and especially in Morocco is dominated by oil products. The latter; whether in the global or the national context; are mainly due to diesel, whose climate impacts are well established, suggesting the search for a greener alternative. Despite its virtues, biodiesel is struggling to impose itself for purely economic reasons. Thus, in order to offer a sustainable solution, while keeping in mind the unpredictable fluctuations (price, demand …). This work proposes a generalization of fuzzy goal programming into fully fuzzy goal programming and a relative application, where the aim is to have a final product at a competitive price. 相似文献
502.
503.
Creed I. F. Trick C. G. Band L. E. Morrison I. K. 《Water, Air, & Soil Pollution: Focus》2002,2(1):81-102
There is considerable spatial heterogeneity in organic carbon (C), total nitrogen (N), and potentially mineralizable nitrogen (PMN) pools in the soils of the Turkey Lakes Watershed. We hypothesized that topography regulates the spatial pattern of these pools through a combination of static factors (slope, aspect and elevation), which influence radiation, temperature andmoisture conditions, and dynamic factors (catenary position,profile and planar curvature), which influence the transport ofmaterials downslope. We used multiple linear regression (MLR)and tree regression (TR) models as exploratory techniques todetermine if there was a topographic basis for the spatialpattern of the C, N and PMN pools. The MLR and TR modelspredicted similar integrated totals (i.e., within 5% of eachother) but dissimilar spatial patterns of the pools. For thecombined litter, fibric and hemic layer, the MLR models explaineda significant portion of the variance (R2 = 0.38, 0.23 and0.28 for C, N and PMN, respectively), however, the residuals werelarge and biased (the smallest contents were over-predicted andthe largest contents were under-predicted). The TR models (9-branch), in contrast, explained a greater portion of the variance (R2 = 0.75, 0.67 and 0.62 for C, N and PMN, respectively) and the residuals were smaller and unbiased. Based on our sampling strategy, the models suggested that static factors were most important in predicting the spatial pattern of the nutrient pools. However, a nested sampling strategy that included scales where both static (among hillslopes) and dynamic (within hillslope) factors result in a systematic variation in soil nutrient pools may have improvedthe predictive ability of the models. 相似文献
504.
Lauren E. Hay Gregory J. McCabe 《Journal of the American Water Resources Association》2002,38(3):847-860
ABSTRACT: A monthly water‐balance (WB) model was tested in 44 river basins from diverse physiographic and climatic regions across the conterminous United States (U.S.). The WB model includes the concepts of climatic water supply and climatic water demand, seasonality in climatic water supply and demand, and soil‐moisture storage. Exhaustive search techniques were employed to determine the optimal set of precipitation and temperature stations, and the optimal set of WB model parameters to use for each basin. It was found that the WB model worked best for basins with: (1) a mean elevation less than 450 meters or greater than 2000 meters, and/or (2) monthly runoff that is greater than 5 millimeters (mm) more than 80 percent of the time. In a separate analysis, a multiple linear regression (MLR) was computed using the adjusted R‐square values obtained by comparing measured and estimated monthly runoff of the original 44 river basins as the dependent variable, and combinations of various independent variables [streamflow gauge latitude, longitude, and elevation; basin area, the long‐term mean and standard deviation of annual precipitation; temperature and runoff; and low‐flow statistics (i.e., the percentage of months with monthly runoff that is less than 5 mm)]. Results from the MLR study showed that the reliability of a WB model for application in a specific region can be estimated from mean basin elevation and the percentage of months with gauged runoff less than 5 mm. The MLR equations were subsequently used to estimate adjusted R‐square values for 1,646 gauging stations across the conterminous U.S. Results of this study indicate that WB models can be used reliably to estimate monthly runoff in the eastern U.S., mountainous areas of the western U.S., and the Pacific Northwest. Applications of monthly WB models in the central U.S. can lead to uncertain estimates of runoff. 相似文献
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506.
1IntroductionNowadays,asthenaturalresourcesbecomemoreandmorelimitedtotheeconomicdevelopmentintheworld,themanagementofhumanbeh... 相似文献
507.
基于AHP LP法的南水北调中线水资源优化配置 总被引:2,自引:0,他引:2
水资源是不可替代的重要自然资源和战略性经济资源,水资源优化配置是解决水资源问题的重要手段。为促进区域水资源供需状况相对平衡,按可持续发展的要求,根据区域水资源优化配置的含义和南水北调河北省受水区的具体情况,以有限水资源综合效益最大为目标,考虑水源可供水量、用户需水量和水环境与经济系统协调发展等约束,采用层次分析法与线性规划法相结合的方法,建立了水资源优化配置模型,并对模型的目标函数、约束条件和主要参数确定进行了初步探讨。最后用该模型进行了南水北调河北省受水区2005年和2010年95%保证率下的水资源优化配置研究,并对求解结果进行了分析、评价及展望。结果表明,南水北调工程实施后,能够解决河北省受水区严重缺水的状况。 相似文献
508.
预测结垢趋势是污水回注中的一项重要工作,通常都要计算离子强度,而离子强度的计算量很大,因此提出了一种替代的估算方法———矿化度法。由于矿化度的测定较为容易,计算简便,建立矿化度和离子强度之间的一元线性关系,使计算得以大大简化。通过中原油田的实例详细说明了一元线性关系的建立方法及判定是否适用的标准,并提出:不同水质情况应分别建立各自的一元线性回归方程。 相似文献
509.
Laturnus Frank von Arnold Karin Grn Christian 《Environmental science and pollution research international》2007,14(1):53-60
Goal, Scope and Background Sewage sludge produced in wastewater treatment contains large amounts of organic matter and nutrients and could, therefore,
be suitable as fertiliser. However, with the sludge, besides heavy metals and pathogenic bacteria, a variety of organic contaminants
can be added to agricultural fields. Whether the organic contaminants from the sludge can have adverse effects on human health
and wildlife if these compounds enter the food chain or groundwater still remains a point of controversial discussion.
Main Features This paper presents an overview on the present situation in Europe and a summary of some recent results on the possible uptake
of organic contaminants by crops after addition to agricultural fields by sewage sludge.
Results Greenhouse experiments and field trials were performed to study the degradation and uptake of organic micro-contaminants in
sludge-amended agricultural soil in crops, such as barley and carrots grown in agricultural soil amended with anaerobically-treated
sewage sludge from a wastewater treatment plant, but studies hitherto have revealed no immediate risks. Common sludge contaminants
such as linear alkylbenzene sulphonates (LAS), nonylphenol ethoxylates (NPE), polycyclic aromatic hydrocarbons (PAH), bis(diethylhexyl)
phthalate (DEHP), showed neither accumulation in soil nor uptake in plants.
Discussion It is assumed that the annual amount of sewage sludge produced in Europe will increase in the future, mainly due to larger
amounts of high quality drinking water needed by an increasing population and due to increasing demands for cleaner sewage
water. Application of sewage sludge to agricultural soils is sustainable and economical due to nutrient cycling and disposal
of sewage sludge. However, this solution also involves risks with respect to the occurrence of organic contaminants and other
potentially harmful contents such as pathogens and heavy metals present in the sludge. There have been concerns that organic
contaminants may accumulate in the soil, be taken up by plants and thereby transferred to humans via the food chain. Results
obtained so far revealed, however, no immediate risk of accumulation of common organic sludge contaminants in soil or uptake
in plants when applying sewage sludge to agricultural soil. With very high dosages of sewage sludge, there may be a risk for
accumulation of very apolar contaminants, such as DEHP, to the soil.
Conclusions Any conclusions on the safe use of sewage sludge in agriculture have to be drawn carefully, as the studies performed until
now have been limited. Further studies are required, and before final statements can be drawn, it is imminent to study a larger
variety of common crops and the effect sewage sludge application may have on a possible accumulation of organic contaminants
in the crops. Furthermore, a larger variety of organic contaminants need to be studied and special focus should be given to
contaminants newly introduced into the environment. Besides investigating possible plant uptake of organic contaminants, the
fate of these compounds in soil after sludge application need to be monitored too. Here, special attention has to begiven
to studies on degradation and the formation of degradation products, to weathering and to leaching effects on groundwater,
to the application of different crops on the same field (crop rotation), to the use of full-width tillage and strip tillage,
and to long term application of sewage sludge on the soil.
Recommendations and Perspectives There are environmental, political as well as economical incentives to increase the agricultural application of sludge. However,
such usage should be performed with care as there are also ways in which sludge fertilisation could harm the environment and
human health. Recently, a new European COST Action (859) has been established covering the field of food safety and improved
food quality. Part of the Action is dealing with the application of sewage sludge in agriculture. Before any political and
economical measures can be taken, the pros and cons have to be sufficiently investigated on a scientific level first.
ESS-Submission Editor: Prof. Elena Maestri (elena.maestri@unipr.it) 相似文献
510.