INTERPRETATION OF THE DUAL PROGRAM FOR OPTIMAL GROUNDWATER HYDRAULIC CONTROL1

ABSTRACT: Optimization formulations for hydraulic control that take the form of linear programs possess a corresponding dual linear program. The economic and physical interpretations of the dual linear program are examined for formulations in which hydraulic head in groundwater systems is constiained. In each case it is shown that the dual linear program has a physically meaningful interpretation. For a hydraulic gradient control formulation used for remedial analysis it is shown that the dual variable can be interpreted as the remedial benefit due to each gradient control constraint. The dual linear program maximizes the remedial benefit. The value of the dual variable can be used to compute such useful properties as the total remedial benefit of pumping at a specific location. For a formulation that optimizes aquifer yield while constraining drawdown the dual variable can be used to measure the total cost of drawdown capacity consumption per unit of pumping at a specific location. The dual program minimizes the cost of drawdown capacity consumption. By examining the meaning of the dual linear program an alternate statement of the problem under study is revealed. Quantities arising from the dual program add to the value of the optimization approach. Significant new information can be derived from existing linear optimization formulations with minimal additional computational effort.     

Preventive environmental strategies for product systems

The paper describes a model for environmental quality and resource efficiency parameters to be used in evaluation of options for improvement of product systems in a life cycle and system perspective. Four main preventive strategies for product system improvements are described and discussed in the paper. (1) Reformulating user needs and requirements to the system; (2) improvement of product system performance; (3) substitution of the whole product systems or system components on different levels; (4) optimization within and between system units and components. These main strategies are discussed with respect to the structure of the product system (the domain theory), and with respect to efficiency in general. It is concluded that at present, it is not possible to make any definite rank of priorities between the different strategies, but that this should be evaluated when more systematic studies of cases are available.     

夯实三大工作体系基础开拓防震减灾事业新局面

本文围绕建设防震减灾三大工作体系,向大家展示了在建设地震监测预报体系、震灾预防体系、地震应急体系方面的具体做法与启示.     

南京娘娘山碱性岩中REE丰度及其在矿物中的分配系数

从具强烈成分分带的娘娘山碱性火山杂岩中分选出7个全岩。2个基质和8个单矿物,测定了REE含量,验证了矿物学和化学成分研究的结论,即岩浆房内主岩浆体顶部存在一个演化程度较高的粗面——响岩质岩浆层。LREE和HREE与其它不相容元素(如Rb、Zr等)在此岩浆层中强烈富集,而Eu则与Sr、Ba、Sc以及相容元素一样强烈亏损,MREE也显示中等程度的亏损。表明分离结晶是该成分梯度产生的主要原因。     

Managing crop residues, fertilizers and leaf litters to improve soil C, nutrient balances, and the grain yield of rice and wheat cropping systems in Thailand and Australia

This paper reports on the influence that residue and fertilizer management have on nutrient balances, soil organic matter (SOM) dynamics, and crop yields of a flooded rice system in northeast Thailand (1992–1997) and a wheat–forage legume rotation in eastern Australia (1992–1998). Both soils had been subject to at least 18 years of cultivation and had lost up to 90% of the original labile (C_L) and 85% of the total carbon (C_T).For the rainfed rice cropping systems of northeast Thailand, a system is described in which small applications of leaf litter from locally grown trees are applied annually to rice paddy soils prior to transplanting. Annual applications of 1500 kg ha⁻¹ of leaf litter from different locally grown shrubs for five seasons resulted in increases in rice grain yield in 1997 of between 20 and 26% above the no-leaf litter control. Nutrient balances, determined by the difference between the inputs (fertilizer and added leaf litters) and outputs (grain and straw), indicated net positive balances of up to 457 kg N ha⁻¹, and 60 kg P ha⁻¹, after five seasons of leaf litter applications. Sulfur and potassium balances resulted in net deficits of up to −13 kg S ha⁻¹ and −52 kg P ha⁻¹, where no leaf litter was applied and rice straw was removed following harvest. Soil carbon (C) concentrations increased significantly only where higher fertilizer rate and rice stubble retention were combined.The poor management of fertilizers and crop residues, and excessive cultivation has also resulted in large soil fertility losses in the grain growing areas of Eastern Australia. After five wheat and two legume/fallow crops, negative N balances of up to −303 kg ha⁻¹ were calculated for the treatments where wheat stubble was not retained and bare fallow leys were used. The balance of nutrients such as K, which are contained in larger proportions in stubble, were found to be up to −362 kg ha⁻¹ on the straw-removed treatments and up to +29 kg ha⁻¹ on the straw-retained treatments. Forage legume leys resulted in short term increases in C_L and the carbon management index (CMI).Sustainable farming systems require that crop yields are stable through the maintenance of soil fertility and the balance of nutrients in the system. Increases in soil C levels require sustained periods of balanced fertilization and residue retention.     

云南省关停企业遗留危险废物管理现状调查研究

通过对云南省关停企业遗留危险废物的产生源、历史变迁、管理现状调查研究,对受污染的场地进行风险评价,提出相应的管理对策.     

国际船舶油污损害赔偿机制评述

介绍和分析了国际船舶油污损害赔偿机制的运转概况，特别注重论述了其主要经验和特点，以供参考。     

川中丘陵区荒坡利用方式对水土流失影响的研究

川中丘陵区荒坡面积占据一定比重,防治水土流失,合理利用荒坡水土资源,对发展本区经济起着重要作用。本文通过网点观测来探求合理利用方式,为荒坡开发利用提供决策依据。     

徐州市城市垃圾综合处理系统研究

针对徐州市城市垃圾污染及其处理情况，运用线性回归法对垃圾产生量进行了定量预测，用层次分析法优选了适合于该市的城市垃圾综合处理系统，从而因地制宜地提出了适合于该城市垃圾处理的方案。     

A methodology for the life cycle and sustainability analysis of manufacturing processes

Life cycle assessment is emerging as a powerful tool in the evaluation of the environmental impact of manufacturing processes. This paper describes a general methodology for the life cycle analysis of manufacturing processes taking into account the flexibility and decision-making potential of knowledge base systems. Emphasis is placed on on-site waste minimisation and associated sustainability characteristics in relation to environmental impact assessment and process improvement. The ensuing software model is applied with some success to an initial study of pulp and paper manufacture.