GEOCHEMICAL INTERPRETATIONS OF GROUNDWATER FLOW SYSTEMS1

ABSTRACT. Interest in the geochemistry of groundwater is increasing owing to the great number of current projects involving underground liquid waste storage, artificial recharge of potable water, accidental contamination of groundwater bodies, sanitary landfills, and pollution monitoring. Geochemical techniques used to facilitate the understanding of a groundwater system range from extremely simple to those requiring sophisticated theories, equipment, and procedures. An interpretation of the simple trilinear diagram for samples collected from the Yucatan Peninsula of Mexico provided evidence that the fresh-water body was only a few tens of meters thick and was underlain everywhere by an extensive body of salt water. A geochemical technique that has been used effectively to identify the source of salt water in coastal aquifers is measurement of the carbon-14 concentrations. Carbon-14 has been used in a regional carbonate aquifer to determine the velocity of groundwater movement, rates of chemical reactions, and distribution of hydraulic conductivity. The application of principles of irreversible thermodynamics to groundwater systems provides a basis for constructing models which permit prediction, over both time and space, of changes in head distribution and chemical character of the water resulting from imposed stresses on the system. In essence, proper application of irreversible thermodynamics combines the potential theory of Hubbert with principles of reversible chemical thermodynamics, such as solution of carbonate minerals, to describe and explain controlling chemical reactions and processes of groundwater systems.     

环境质量评价模糊集理论与模式研究

探讨了模糊集理论方法对环境质量评价的可行性，以大气环境质量评价为例，叙述了这种方法的研究程序及计算步骤。研究表明，采用模糊集理论方法对大气环境质量进行评价，结果结果合理，方法可行，有一定的参考价值。     

DERIVATION OF THE GAMMA DISTRIBUTION BY USING THE PRINCIPLE OF MAXIMUM ENTROPY (POME)1

The principle of maximum entropy (POME) was used to derive the two-parameter gamma distribution used frequently in synthesis of instantaneous or finite-period unit hydrographs. The POME yielded the minimally prejudiced gamma distribution by maximizing the entropy subject to two appropriate constraints which were the mean of real values and the mean of the logarithms of real values of the variable. It provided a unique method for parameter estimation. Experimental data were used to compare this method with the methods of moments, cumulants, maximum likelihood estimation, and least squares.     

Spatial Extent Of Degraded Sediment Quality In Puget Sound (Washington State, U.S.A.) Based Upon Measures Of The Sediment Quality Triad

A survey was designed and conducted to determine the severity, spatial patterns, and spatial extent of degraded sediment quality in Puget Sound (Washington State, USA). A weight of evidence compiled from results of chemical analyses, toxicity tests, and benthic infaunal analyses was used to classify the quality of sediments. Sediment samples were collected from 300 locations within a 2363 km² area extending from the US/Canada border to the inlets of southern Puget Sound and Hood Canal. Degraded conditions, as indicated with a combination of high chemical concentrations, significant toxicity, and adversely altered benthos, occurred in samples that represented about 1% of the total area. These conditions invariably occurred in samples collected within urbanized bays and industrial waterways, especially near the urban centers of Everett, Seattle, Tacoma, and Bremerton. Sediments with high quality (as indicated by no toxicity, no contamination, and the presence of a relatively abundant and diverse infauna) occurred in samples that represented a majority (68%) of the total study area. Sediments in which results of the three kinds of analyses were not in agreement were classified as intermediate in quality and represented about 31% of the total area. Relative to many other estuaries and marine bays of the USA, Puget Sound sediments ranked among those with minimal evidence of toxicant-induced degradation.     

加饲不同数量的沼液对育肥猪的影响

用4组共32头仔猪进行了三种不同喂量的沼液饲养试验。试验结果表明,在饲料消化能为12.1MJ/kg、粗朊10％的营养水平下,按饲料量(风干重)的1.5倍加饲沼液对育肥猪有显著的增重效果(P<0.05),平均比对照净增20.6％,饲料利用率提高17％,育肥期缩短25％左右,有明显的生态效益和经济效益。     

基于遗传神经网络模型的大气环境质量评价方法

设计了用遗传算法训练神经网络权重的新方法，实验结果显示了遗传算法快速学习网络权重和全局搜索的能力，有效地解决了BP算法的局部收敛问题。误差反向传播的遗传——神经网络(GA—BP)模型用于大气环境质量综合评价，具有简便、准确、客观和适应性强等优点。     

臭氧光催化降解地下水中天然有机物的研究

在现场开展了中试规模的臭氧光催化降解天然有机物的研究.研究表明,对大分子天然有机物占很大比例且重碳酸盐含量较高的地下水,臭氧投加量10 mg/L和反应时间10 min条件下,TOC的去除率不到20%,但UV254和三卤甲烷生成潜力(THMFP)去除率分别达到近60%和33.5%.臭氧光催化与活性炭吸附相连,能显著提高UV254的THMFP的去除率,但TOC去除率并不明显高于单独活性炭吸附.臭氧光催化使大分子有机物转化为小分子有机物,后者在活性炭上的吸附性提高且生化性改善,可望在生物活性炭上更有效地去除.     

一般工程中深孔爆破技术的初步探讨

中深孔爆破技术在一般工程中得到最为广泛的推广和应用,合理地确定中深孔爆破的各项技术参数和有效地控制爆破中产生的有害效应,能够取得理想的工程效益.中深孔爆破的各项技术参数之间存在着相互关联性,寻找他们之间的内在联系,可以合理地优化爆破方案.中深孔爆破产生的有害效应有规律可寻,只要掌握和合理地应用,能够降低和消除中深孔爆破产生的有害效应.     

岩爆倾向性的改进有限云评价模型与工程应用

为解决深部开采顶板岩爆评价问题,以挑水河磷矿为例,提出由3个岩爆倾向性评价指标e0/ec、e1/ec、ec/et组成的综合性评价指标体系,采用消除云雾化的综合权重法,建立顶板多指标岩爆倾向性的改进有限云评价模型;通过FLAC3D模拟计算采场的应力值,获得e0/ec、e1/ec、ec/et的参数值;开展挑水河磷矿顶板岩爆...     

MULTICRITERION DECISION MAKING FOR FLOOD CONTROL OPERATIONS: THEORY AND APPLICATIONS1

ABSTRACT: Flood control operations are generally complex in nature, as they are often associated with a large quantity of uncertain factors in combination of noncommensurable criteria. It has been found that the use of fuzzy set theory coupled with multicriterion decision making (MCDM) methods is very promising. In this paper, a multicriterion fuzzy recognition model is established for flood control operations. A subjective preference and iterative weights method is proposed for weight assessment. First, an initial solution of criteria weights, which is directly analyzed from the selected alternatives, is obtained by using the proposed fuzzy recognition model. Then, according to their knowledge related to real time flood operations, operators may modify the initial weights if necessary. When the relative membership grades of alternatives belonging to all rankings are fixed, a defuzzification equation is used to calculate the rank feature value vector. Based on the rank feature value vector, one can evaluate the alternative set. Two flood operation cases are provided to illustrate the application of the proposed model. With the incorporation of the operator's knowledge related to flood operations, the proposed model is flexible in giving weights and realizes more practical flood control operations.