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251.
我们所看到的许多资料的研究显示,消费者通常对可持续思想是支持的和要求保证制造商是负责任的.  相似文献   
252.
The European Union Water Framework Directive recognises the need for and value of biological monitoring. This paper reviews the modelling approach known as River Invertebrate Prediction and Classification System (RIVPACS for assessing the ecological quality of river sites using macroinvertebrate sampling. The RIVPACS philosophy is to develop statistical relationships between the fauna and the environmental characteristics of a large set of high quality reference sites which can be used to predict the macroinvertebrate fauna to be expected at any site in the absence of pollution or other environmental stress. The observed fauna at new test sites can then be compared with their site-specific expected fauna to derive indices of ecological quality. All methodological decisions in any such model development have implications for the reliability, precision and robustness of any resulting indices for assessing the ecological quality and ecological grade (‘status’) of individual river stretches. The choice of reference sites and environmental predictor variables, the site classification and discrimination methods, the estimation of the expected fauna, and indices for comparing the agreement, or lack of it, between the observed and expected fauna, are all discussed. The indices are assessed on the reference sites and on a separate test set of 340 sites, which are subject to a wide range of types and degrees of impairment.  相似文献   
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254.
Policy indicators applied at a national scale can have considerable financial impact for resource allocations to individual counties, especially if there are extreme local factors. This article develops arid explores a new measure of population dispersal and sparsity and discusses the impact of this indicator in a variety of locations, by using GIS techniques.  相似文献   
255.
This paper describes the recent economic history of the Scottish economy and uses a synthesised theory of labour market segmentation and the dual economy to identify the origins of the relative decline of Scottish industry and labour over the period, critically evaluating the role of the SDA and of government policy in general. Incorporating the impacts of takeover and merger of indigenous companies, the promotion of the branch plant economy, the selective effects of emigration and training schemes, and the reliance on small and medium sized companies to regenerate the economies of city‐regions, an analysis based on the importance of the centre‐periphery relations of monopoly capitalism for the Scottish economy is undertaken.  相似文献   
256.
The promotion of renewable energy during the last decade did not result in widescale application of the technology. In many cases, technologies were promoted before they were commercially viable or were inappropriately selected for the particular end-use application. In other cases, a lack of local technical expertise and support infrastructure was absent to sustain the technology once it had been placed in the field. There was also a loss of donor interest and funding for renewables concomitant with the decline in oil prices. This paper attempts to summarize lessons learned from this decade of experience with renewable energy and to offer criteria and suggestions for future activities in transferring renewable energy technology.  相似文献   
257.
The physical and chemical qualities of the process effluent and the tailings dam wastewater of AngloGold-Ashanti Limited, a gold mining company in Ghana, were studied from June to September, 2010. The process effluent from the gold extraction plant contains high amounts of suspended solids and is therefore highly turbid. Arsenic, copper and cyanide were identified as the major pollutants in the process effluent with average concentrations of 10.0, 3.1 and 21.6 mg?L?1, respectively. Arsenic, copper, iron and free cyanide (CN?) concentrations in the process effluent exceeded the Ghana EPA discharge limits; therefore, it is necessary to treat the process effluent before it can be discharged into the environment. Principal component analysis of the data indicated that the process effluent characteristics were influenced by the gold extraction process as well as the nature of the gold-bearing ore processed. No significant correlation was observed between the wastewater characteristics themselves, except for the dissolved oxygen and the biochemical oxygen demand. The process effluent is fed to the Sansu tailings dam, which removes 99.9 % of the total suspended solids and 99.7 % of the turbidity; but copper, arsenic and cyanide concentrations were still high. The effluent produced can be classified as inorganic with a high load of non-biodegradable compounds. It was noted that, though the Sansu tailings dam stores the polluted effluent from the gold extraction plant, there will still be serious environmental problems in the event of failure of the dam.  相似文献   
258.
Abstract

Artificially contaminated (spiked) natural soils were solidified/stabilized using various combinations of commonly used additives, such as lime, cement, fly ash, activated carbon, and silica fume. The effectiveness of the solidification/stabilization (S/S) processes was evaluated based on experimental findings from compaction testing, unconfined compressive shear strength, and X-ray diffraction (XRD). Correlations of limited reliability between unconfined compressive strength and penetrometer and torvane measurements were derived. Results from XRD experiments indicated that certain organic contaminants (i.e., naphthalene and pyrene) might impact the S/S processes for a given combination of additives. The type and amount of organic contaminants also affected the pozzolanic reactions. Specifically, the absence or small peak intensity of pozzolanic product XRD patterns for a given combination of additives was a good indication that the type and the amount of organic contaminant present inhibited pozzolanic reactions. This phenomenon was tested and confirmed for actual field-contaminated samples.  相似文献   
259.
260.
A case study of the Yorkshire Derwent (UK) catchment is used to illustrate an integrated approach for assessing the viability of policy options for reducing diffuse nitrate losses to waterbodies. For a range of options, modeling methods for simulating river nitrate levels are combined with techniques for estimating the economic costs to agriculture of modifying those levels. By incorporating spatially explicit data and information on catchment residence times (which may span many decades particularly in areas of groundwater discharge) a method is developed for efficient spatial targeting of measures, for example, to the most at-risk freshwater environments. Combining hydrological and economic findings, the analysis reveals that, in terms of cost-effectiveness, the ranking of options is highly sensitive to both (i) whether or not specific stretches of river within a catchment are regarded as a priority for protection, and (ii) the criterion of nitrate concentration deemed most appropriate as an indicator of the health of the environment. Therefore, given the focus under European legislation upon ecological status of freshwaters, these conclusions highlight the need to improve understanding of mechanistic linkages between the chemical and biological dynamics of aquatic systems.  相似文献   
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