基于可变模糊集对立统一定理的水安全评价研究

为了与集对分析法得到的关于水安全评价的结果作比较,在目前研究的基础上,应用可变模糊集理论中的对立统一定理和水资源系统评价理论、模型与方法,研究了水安全综合评价问题,并列举了实例进行比较。综合评价结果表明,该方法理论严谨、概念清晰、计算简便,无论在理论上还是应用上都优于基于集对分析的水安全评价方法。     

基于广义对比加权的水安全综合指数评价

为了构建水安全综合评价模型,在分别提出"正向"和"逆向"指标安全指数公式基础上,采用广义模糊对比加权法对水安全评价体系的各个子系统进行赋权,得到水安全综合评价指数公式。应用该方法对山东省区域水资源进行安全评价,并与应用属性识别理论法和贝叶斯法对该例的评价结果相比较,结果一致,表明了该方法应用于区域水安全评价的可行性和实用性。     

基于边际效益递减原理的城市水安全评价方法

通过对城市水安全内涵的剖析和系统分析,将城市水安全系统分为支持子系统、协调子系统和防洪子系统,建立了逻辑清晰、层次分明的评价指标体系,并选用层次分析法确定了各层次指标的权重。在分析指标变化对城市水安全的影响规律的基础上,借鉴边际效益递减原理,建立了一种新的指标评价方法与模型。利用所确立的评价方法,对昆明城市水安全的现状及趋势进行了评价与预测,其得分为0.574,处于"不安全"状态,且有恶化趋势。该评价结果与实际基本相符,表明该方法体系有效、可靠,可用于城市水安全的评价研究。     

基于模糊集对分析法的新疆水资源安全评价

根据区域水资源现状,选取18个评价指标,建立了包括水资源、经济社会、生态环境、供需4个准则层的区域水安全评价指标体系;通过熵权法确定指标权重,采用基于模糊集对分析的水资源安全评价方法,对2016年新疆水资源安全状况进行了评价。结果表明:新疆水资源整体的安全状况属于基本安全等级,空间分布上北疆优于南疆和东疆;评价结果与物元分析法和综合指数法评价结果总体上一致,评价结果具有合理性。     

区域水安全研究浅议

本文对国内外研究现状回顾的基础上．提出了水安全主要研究的内容，包括水安全理论研究、水足迹研究、水安全评价和水安全模拟等。认为采用地理信息系统与数学模型集成研究的方法，是水安全研究的主要方法。     

基于对立统一与质量互变定理的水资源系统可变模糊评价新方法

根据可变模糊集理论导出的唯物辩证法对立统一与质量互变规律的数学定理--对立统一与质量互变定理,提出水资源系统新的可变模糊评价方法.文中以水资源可持续利用程度和水安全综合评价两个评价实例,说明了新方法的原理、模型与计算步骤.与模糊综合评判方法和集对分析评价法进行比较分析表明,该方法具有理论严谨、模型简洁和计算简便的优点,...     

双隐层BP神经网络模型在区域水安全评价中的应用

基于BP神经网络的基本原理和方法,构建双隐层BP神经网络水安全评价模型.以相关文献资料进行模型评价效果验证.验证表明:所建立的双隐层BP评价模型和评价方法是合理可行的,是一种可以运用的区域水安全评价方法.基于此模型,结合丰水地区区域实际,利用层次分析法构建了符合丰水地区水安全评价的指标体系和标准,以文山州区域水安全评价为例进行分析.结果表明:文山州各评价区域不同规划水平年水安全评价等级为Ⅳ～Ⅱ级,即处于不安全与安全之间,客观反映了文山州现状及中、长期水安全状况,符合区域实际,评价结果可作为研究区域水安全评价的参考依据.     

指标变换值表示的水安全评价的普适指数公式

适当设定水安全指标的参照值和指标值的变换式,并对各指标值进行了变换,使得以变换值表示的不同指标皆"等效"于一个规范指标,从而不同指标的水安全评价指数公式皆可以用该"等效"指标相应的指数公式替代。在满足设定的优化准则条件下,采用猴王免疫进化算法对公式进行优化,分别得到优化后对23项水安全指标皆适用的5个水安全评价的普适指数公式。对所获公式的可靠性进行理论分析以及对其实用性进行效果检验后,其评价结果与其他方法评价结果相一致,并与实际相符合。结果表明:水安全评价的多种形式的普适指数公式皆具有形式简洁、计算简便和普适通用的特点。     

水安全系统多变量迭代综合评价模型的应用

现有的水安全评价方法多为指标的加权和,忽略了指标间的相互作用对整个系统评价带来的影响。在证实水安全系统具有复杂适应性的基础上,基于复杂适应系统的4个特性和3个机制及其之间的相互关系,从各特性和机制协调度的角度出发,建立了水安全系统多变量迭代评价模型。该模型充分考虑了系统内部指标间的复杂非线性关系,评价结果更加科学、客观。对建三江地区水安全系统进行评价,结果与该地区实际情况相符,充分证实了该模型的可行性与有效性。     

基于ABC-BP模型的阿什河流域水安全评价

针对水安全评价的特点,将人工蜂群算法(ABC)引入到BP神经网络中,对其网络结构、初始权值和阈值进行优化,通过将BP神经网络参数的优化过程转化为蜜蜂寻找最佳蜜源的过程,建立了基于人工蜂群算法优化的BP网络。选取11个水安全评价指标,以阿什河流域2011年阿城观测断面实测数据为例,对其2011年的水安全状况进行了全面的评价。研究结果表明:阿什河流域2011年水安全等级普遍较差,均在Ⅲ级以下,与实际情况相符,且评价结果具有很强的稳定性和鲁棒性。因此,采用ABC-BP模型对流域水安全进行评价是一种行之有效的方法,研究成果为流域水安全评价提供了新的思路和方法。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.