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31.
水质环境质量评价宜采用多项控制指标进行综合评价。在模糊理论和考虑优先隶属度的基础上,通过实例推导出水环境质量多目标模糊决策评价图,用以说明两组或两组以上的数据或变量的相互联系,以非常直观地分析概念,讨论水质变化趋势。模型可客观地评价水域单元的各类水质指标。 相似文献
32.
This paper explores household (HH)-level livelihood dynamics and determinants since construction of the Samanalawewa Hydroelectricity Reservoir (SHER) in the Samanalawewa watershed, Sri Lanka. The research is based on data from a structured questionnaire survey of 201 randomly selected households (HHs) in upstream and downstream areas. Livelihood dynamics at two separate points in time (1988 and 2008) were assessed based on a sustainable livelihood framework (SLF). Impact of livelihood determinants on livelihood was analysed using factor and regression analysis techniques, followed by an optimisation procedure to suggest requirements in selected significant determinants to improve the livelihood of various categories of farm HH. In both upstream and downstream areas, livelihood assets, viz. physical, social and human capital, increased significantly, while access to natural and financial capital decreased significantly and slightly, respectively, during last two decades. The factor analysis extracted six factors in the upstream area and seven in the downstream area. The derived regression models show that nine variables in the upstream area and ten in the downstream area are major determinants of HH livelihood. Based on optimisation results, policy implications are discussed in relation to needed improvements in livelihood determinants to improve overall livelihood of HHs. 相似文献
33.
This paper outlines the three types of correlation that will characterise most attempts to model land contamination and optimise site assessment strategies. The first type of correlation is that which exists between indicators of contamination. A potential methodology for handling these correlations is given. The second type of correlation is the spatial (auto) correlation between different locations on a site. This has been previously handled through methods such as Kriging interpolation. The possible benefits of integrating the analysis of the first two types of correlation are very briefly discussed. The third type of correlation is that which exists between the information from site samples. Examples of this type of correlation are given. 相似文献
34.
35.
《International Journal of Sustainable Engineering》2013,6(3):267-277
For many manufacturers, the cost of replacing returned products may more than offset the cost of producing parts with a higher quality. This is especially true if good parts from returned products are used to remanufacture aftermarket products. Furthermore, such policy allows for satisfying a customer population with a variable expectation for acceptable quality. In this study, the total cost of supplying a given demand is derived as an analytical function of the targeted primary production rate and product quality when the demand is satisfied with a combination of primary and remanufactured products. The decision variables of this function consist of the primary production rate and the designed product and production quality. This cost is then minimised to determine the production rate and the optimum quality to target. A numerical example is provided and used to demonstrate the application of this function. This example also demonstrates the use of the proposed solution for optimising quality when there is a limit on primary production size. The example also demonstrates the use of the function for optimising service levels. The results show a close match between the theoretical functions developed in this study and those obtained from a Monte Carlo simulation model. 相似文献
36.
《Process Safety and Environmental Protection》2014,92(6):917-928
RCNet is a spreadsheet-based software for the synthesis of resource conversation networks (RCNs) for planning the efficient use of material resources (e.g., water, utility gases, solvents) in industrial plants. The software is developed based on the well-established process integration tools, namely pinch analysis and mathematical programming techniques. In the first stage, pinch analysis is used to determine maximum resource conservation targets prior to detailed RCN design. In the second stage, mathematical optimisation is then used to determine the optimal flowrate allocation between process sources and sinks of the RCN, to achieve the performance targets. RCNet is applicable for various industrial applications. To date, no generic software has been developed to handle water minimisation, hydrogen recovery and property integration, which is the main subject of this work. In the developed software, same interface and platform can be used to solve abovementioned problems independently. For illustration, three literature examples on water minimisation, hydrogen recovery and property integration, as well as an industrial case study are solved using RCNet. 相似文献
37.
Lei Qiao Robert B. Herrmann Zaitao Pan 《Journal of the American Water Resources Association》2013,49(2):343-358
Abstract: This study incorporates the newly available Gravity Recovery and Climate Experiment (GRACE) water storage data and water table data from well logs to reduce parameter uncertainty in Soil and Water Assessment Tool (SWAT) calibration using a SUFI2 (sequential uncertainty fitting) framework for the Lower Missouri River Basin. Model evaluations are performed in multiple stages using a multiobjective function consisting of multisite streamflow and GRACE water storage data as well as a groundwater component. Results show that (1) a model calibrated with both streamflow and GRACE data simultaneously can maintain the water balance for the whole basin, but may improperly partition surface flow and base flow. Additional inclusion of the groundwater constraint can significantly improve the model performance in groundwater hydrological processes. In our case, the estimation of specific yield of shallow aquifers has been increased to 10?2 from previous much underestimated level (<10?3). (2) The daily streamflow data are needed to confine the parameters related to water flow in channels such as the Manning’s coefficient, which are less sensitive to the monthly simulations. (3) Parameters are nonuniformly sensitive for different goal variables, and thus, proper specification of a prior distribution of parameters may be the key factor for global optimization algorithms to obtain stable and realistic model performance. 相似文献
38.
Cost effective environmental control technology for utilities 总被引:1,自引:0,他引:1
Yan Fu 《Advances in Environmental Research》2004,8(2):173-196
On September 24, 1998, new regulations announced by the US EPA require 22 eastern states plus the District of Columbia to develop state implementation plans to reduce ground-level ozone through the reduction of nitrogen oxide (NOx) emissions (Cooper, 1998). This plan calls for a 28% NOx cut in the summer time (1.2 million tons) by 2007. This calls for utilities to develop new, efficient, and robust post-combustion NOx control technologies. A new environmental control technology called low temperature oxidation (LTO) system, which can reduce NOx emissions below measurable levels (i.e. 2 ppm using process analyzers) at low temperature (125-325 °F), was awarded the best available control technology and the lowest available emission reduction technology by the US EPA in April 1998. Ozone is employed to oxidize nitric oxide (NO) to dinitrogen pentoxide (N2O5) at a low temperature in an oxidizer, which is then easily absorbed by water in a scrubber. Bench scale and pilot plant tests have shown that the LTO process can almost completely remove the NOx emissions (i.e. NOx emissions are below levels measurable using process analyzers). This proved that the LTO system is an attractive process to meet the stricter NOx regulations. There are multiple benefits of the LTO system besides removal of NOx emissions, includes reduction of SOx and CO emissions, and no secondary air emissions (NH3, N2O). In order to obtain minimum NOx emissions, extra ozone needs to be supplied. The cost of the process also increases nonlinearly as emissions decrease. This poses a challenging multiobjective optimization problem where emissions like NOx and SOx need to be minimized, while minimizing the system cost as well as extra ozone. This problem is addressed using a new and efficient multiobjective optimization framework. This framework will provide designs that are cost effective as well as environmentally friendly. 相似文献
39.
Norihiro Takama Daniel P. Loucks 《Journal of the American Water Resources Association》1981,17(3):448-453
This paper presents a solution method for a class of multiobjective problems characterized by a hierarchical structure of decisionmaking and a large number of alternatives. The method, consisting of a multilevel problem formulation and an interactive algorithm, has distinct advantages for identifying preferred solutions to problems having those characteristics. The method is illustrated to a problem involving waste water treatment in the chemical industry. 相似文献
40.
Jenq‐Tzong Shiau Fu‐Chun Wu 《Journal of the American Water Resources Association》2006,42(5):1179-1191
ABSTRACT: This paper presents a quantitative assessment framework for determining the instream flow under multiobjective water allocation criteria. The Range of Variability Approach (RVA) is employed to evaluate the hydrologic alterations caused by flow diversions, and the resulting degrees of alteration for the 32 Indicators of Hydrologic Alteration (IHAs) are integrated as an overall degree of hydrologic alteration. By including this index in the objective function, it is possible to optimize the water allocation scheme using compromise programming to minimize the hydrologic alteration and water supply shortages. The proposed methodology is applied to a case study of the Kaoping diversion weir in Taiwan. The results indicate that the current release of 9.5 m3/s as a minimum instream flow does not effectively mitigate the highly altered hydrologic regime. Increasing the instream flow would reduce the overall degree of hydrologic alteration; however, this is achieved at the cost of increasing the water supply shortages. The effects on the optimal instream flow of the weighting factors assigned to water supplies and natural flow variations are also investigated. With equal weighting assigned to the multiple objectives, the optimal instream flow of 26 m3/s leads to a less severely altered hydrologic regime, especially for those low‐flow characteristics, thereby providing a better protection of the riverine environment. 相似文献