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41.
利用1990年以来安徽嘉山台的多极距电阻率观测资料进行反演分析,结果显示: 嘉山台的浅层(第一层)电阻率变化幅度最大,认为是受气象和灌溉等因素的干扰; 第二层变化幅度迅速减小; 第三层变化平稳; 深层(第四层)电阻率变化幅度比二、 三层大,可能与层厚为∝有关,原因尚须进一步研究。 相似文献
42.
可持续发展能力建设的理论分析与重构 总被引:8,自引:1,他引:7
本文从《21 世纪议程》所述的可持续发展能力的解释出发,首次定义了可持续发展能力建设的概念,全面阐术述了能力建设的基本概念和实质内涵;同时,从理论上论述了能力建设的现实意义、能力建设的途径以及能力建设在实施可持续发展战略中基础作用。 相似文献
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45.
Xiaoying Yang Benedykt Dziegielewski 《Journal of the American Water Resources Association》2007,43(1):160-169
Abstract: Thermoelectric power generation is responsible for the largest annual volume of water withdrawals in the United States although it is only a distant third after irrigation and industrial sectors in consumptive use. The substantial water withdrawals by thermoelectric power plants can have significant impacts on local surface and ground water sources, especially in arid regions. However, there are few studies of the determinants of water use in thermoelectric generation. Analysis of thermoelectric water use data in existing steam thermoelectric power plants shows that there is wide variability in unitary thermoelectric water use (in cubic decimeters per 1 kWh) within and among different types of cooling systems. Multiple‐regression models of unit thermoelectric water use were developed to identify significant determinants of unit thermoelectric water use. The high variability of unit usage rates indicates that there is a significant potential for water conservation in existing thermoelectric power plants. 相似文献
46.
Chris Riedy Jennifer Kent Nivek Thompson 《Journal of Environmental Planning and Management》2019,62(1):151-171
Effective environmental governance requires institutional change. While some actors work to change institutions, others resist change by defending and maintaining institutions. Much of this institutional work is ‘meaning work’, which we define as the practice of crafting, adapting, connecting and performing meanings to purposively create, maintain or disrupt institutions. This paper constructs a concept of meaning work that highlights agency in carrying meanings across scales and between discursive layers, while noting the structuring role of prevailing discourses. It grounds the concept using two environmental governance cases at very different scales: a local democratic innovation employed by Noosa Council in Queensland, Australia; and the international campaign to divest from fossil fuels. The cases demonstrate the diversity of meaning work and the difficulty of achieving deep discursive change. They point to the need for environmental governance practitioners to rework existing meanings to construct compelling stories for change, taking advantage of narrative openings. 相似文献
47.
Lotte E. Bontje Sharlene L. Gomes Zilin Wang Jill H. Slinger 《Journal of Environmental Planning and Management》2019,62(1):30-50
Institutional work offers a promising lens for understanding institutional change, focusing on the efforts of actors in creating, maintaining or disrupting institutions. In this paper, we explore the capacity of a narrative approach to provide insights on institutional work, using a case study from the coast of Sweden. We identify four narratives that compete in the policy discourse regarding erosion and beach nourishment in the coastal province of Scania. The narratives reveal that actors hold different beliefs concerning the magnitude of the erosion problem, the division of responsibilities and the suitability of sand nourishment as a coastal protection measure. The narrative competition is considered reflective of past institutional discussions and ongoing institutional work in coastal management in Scania, confirming that narratives are used as sense-making and meaning-giving devices in institutional discussions. 相似文献
48.
ABSTRACT. Planning an optimal system of activities for generating economic goods and services within an existing natural resource capacity is a difficult problem to solve. A mathematical programming model with the capacity to check multiple resource demand and supply compatibility over many time periods was developed for the solution to this type of problem. The characteristics of natural resource supply and the demand of activities were utilized to reduce the number of time periods and to minimize the loss of the dynamic reality of the problem. Reduction in the number of time periods extended the capability of the model to the solution of complex resource planning problems without oversimplification. 相似文献
49.
ABSTRACT. This research examines the impact of high rates of interest upon the least cost system design for urban drainage systems when water quality is a critical parameter. Results of examination of twelve alternative system designs in a case study watershed indicate the least cost study design is highly sensitive to the rate of interest, but not sensitive to the water quality parameters. When the high rates of interest currently prevalent are introduced into the model those systems which contain open channel collection components are selected as the least cost system. At low rates of interest pipeline collection components are selected as the least cost system. Holding pond components of system design are cost effective at several levels of water quality. They are neutral to the rate of interest so they are incorporated in least cost systems at all the levels of interest rates. The results of the study indicate that at the current high rates of interest open channel collection systems and holding ponds are cost effective system components to achieve selected levels of water quality in urban drainage system design. 相似文献
50.
James Fulton William L. Chase 《Journal of the American Water Resources Association》1979,15(2):426-435
ABSTRACT: The Phoenix metropolitan area has a unique combination of circumstances which makes it one of the prime areas in the Nation for waste water reuse. Overriding all of these conditions is the long-term inadequacy of the existing water supplies. The Salt River Valley has a ground water overdraft of about 700,000 acre feet per year. To help alleviate this situation, the Corps of Engineers in conjunction with the MAG 208 is looking at ways to reuse a projected 2020 waste water flow of 340,000 acre feet per year. Reuse options identified include ground water recharge, agricultural irrigation, turf irrigation, recreational lakes, fish and wildlife habitats, and industrial cooling. These look nice on paper but before they can be implemented, some hard questions have to be answered, such as: How acceptable are local treatment plants when 15 years ago there was a major push to eliminate local plants; is the Phoenix area ready for reuse in urban areas; what are people willing to pay for water; who benefits if a city goes to ground water recharge; how much agriculture will be left in the area by 2020? These and other questions must be resolved if reuse is to become a viable option in water resource planning in the Phoenix area. Summary. Large scale reuse of waste water conforms with the national goal of better resource management through recycling. The Phoenix metropolitan area has a unique combination of circumstances which makes it one of the prime areas in the nation for waste water reuse. Some of the most notable conditions are: the existence of a large and rapidly growing urban area which is in the process of planning for future waste water management systems; the existence of agricultural areas which are projected to be farmed well into the future, and the existence of constructed and planned major recreational systems such as Indian Bend Wash which can use recycled waste water; the existence of extensive depleted ground water aquifers; the need for a dependable source for the cooling of the Palo Verde Nuclear reactors; and finally, overriding all of this, the long-term inadequacy of the existing water supplies. Given this, one would expect to find total reuse within the Phoenix metropolitan area. Reuse is taking place with irrigation and nuclear power cooling to the west but there is no long term plan which looks at the Valley as a whole and considers waste water as part of the Valley's water resources. The Corps 208 plan is looking at waste water in this manner but initial analysis shows that although reuse is technically feasible there are many financial, social, institutional, and political questions still to be answered. These include: determining the value of existing diminishing water sources and what people are willing to pay for the next source of water; are people willing to identify priority uses of water for the area so that water of varying quality is put to its highest and best use; will the present institutional boundaries remain to create water-rich and water-poor areas; and will legislation be forthcoming to simplify the complex surface and ground water laws that presently exist? The Corps 208 study will not be able to answer these questions, but the goal at the moment is to identify feasible reuse systems along with decisions the public, owners, agencies, and politicians must make to select and implement them. If some sort of logical process is not developed and public awareness not increased, the chance for a long-term plan to utilize waste water as a major element in the Phoenix area water resource picture, may be missed. 相似文献