华南碧桂园六期生活及消防给水系统设计

介绍了地形高差较大的大型居住区华南碧桂园六期的生活及消防给水系统设计。结合地形和建筑规划布置,生活给水系统采用了节能、供水安全稳定性能好的高位水池供水方式,并且按给水竖向分区设置了2个不同高度的高位水池;消防给水系统采用常高压供水方式,环状管网布置,安全稳定可靠。阐述了设计参数、高位水池、二次加压给水泵房、管网布置等设计内容。     

重力供水系统在非洲城市供水工程设计中的应用

介绍了非洲某国首都N市某供水工程的设计概况。项目充分结合了当地的地形和水文条件,在城市北部山区拦河建坝作为城市的一个供水水源,原水重力流到给水厂经处理后,重力输送至供水区域的高位水池,再由高位水池进行配水。整个系统从原水输送、净化处理、清水输配均采用重力自流,单位制水成本仅为0.03美元/m~3,较好地契合了当地城市的特点,满足了供水的需求。     

山地城市分区给水优化设计研究

利用城市给水管网分区给水的理论,提出了山地城市给水管网分区给水优化设计的原则和方法,并对3个山地城市给水管网分区给水的工程进行了研究和优化设计.     

管网水池工程在山区人畜饮水、灌溉中的应用

本文论述了利用管道(减少沿线生态破坏)从国家级自然保护区内徐家坝水库引水、跨流域调水,解决沿线人畜饮水及山地灌溉的设计思路、创新特点及效益分析。根据供水需求及缓解管网压力要求,分片、分段设置高位大水池,结合小水池、小水窖及爱心水窖连通蓄水,保证每一滴水都储存备用。利用高位水池自身压力及与耕地落差实现喷灌、滴灌等节水灌溉技术应用,解决山区、半山区人畜饮水及耕地灌溉。     

特大山地城市供水可靠性与安全保障措施研究

以重庆市观景口水利枢纽工程为例,分析特大山地城市主干供水管网系统的特点与问题,介绍供水主干管网的可靠性评价指标和可靠度计算模型.基于分析结果,结合目前关于供水管网安全保障体系的具体技术措施,从维持管网正常工作和应对管网突发事件两方面,对山地城市供水管网建设进行探讨,合理有效地提高系统的安全性和可靠性.     

重庆市云阳县城市给水总体规划设计

针对重庆市云阳县的地形地势特点,对城市给水系统进行了规划设计,提出了分区域供水、分压供水等规划方案。同时,在各片区的对应分区之间设置连通管道,将各高程分区管网连接成环。在联通管道上设置应急闸阀,通过控制应急闸阀的启闭,对各片区的供水进行合理调配。城市给水总体规划的提出为实现云阳县安全供水的目标提供了可靠的理论依据。     

群岛供水多座高位水池自动配水控制工艺优化探讨

针对长海县各岛需水量不均衡、各岛高位水池高程各异、各高位水池进口液位控制阀机械制动事故率高以及水位不能自动调节等缺陷,采用增加电磁阀及远程控制系统的工艺优化方案,有效解决了不同需水量、不同蓄水量、不同池底高程情况下的多座高位水池液位控制问题。最终实现了水量的合理分配,降低了供水事故发生率,保证了全县供水及水质安全和群岛供水设施安全。     

家用蓄水箱

随着城市的发展,社会生产和生活用水量急剧增加,城市管网的供需矛盾也相应增大,高层楼房间断供水较普遍.分析其原因有三点:①总需求大于总供给.②实际供水时变化系数较大,而调节构筑物和设施偏小.③管径偏小或管段铺设年代较早受内腐蚀因素影响,管网阻力加大,导致供水压力不足.目前,在城市给水管网系统中,通常采用气压罐、调速水泵及管道泵等加压设施,缓解局部区域供     

住宅小区供水方式的探讨

1.几种供水方式的优缺点比较虽然住宅小区从城市管网上直接供水无论在技术上经济上都是最好的。但杭州市给水管网中目前在水量、水压上都能满足的地区仅占城市总面积的一半左右,其余都要采取其他方式供水。比较普遍采用的是屋顶水箱、水池水泵水塔、水池气压罐等     

蒙山县屯巴山灌片高效节水灌溉工程设计

介绍了蒙山县屯巴山灌片高效节水灌溉工程的基本情况,论述了灌溉方式、供水方式、管材比选情况。选定了低压管灌、水泵加高位水池供水、PE管道的节水灌溉方式,并根据现有地形、地质、水源条件、作物种植结构等条件,在连片面积4 000亩的蜜柚种植区范围内论述了低压管灌的灌溉制度、高位水池及管网布置设计。     

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。     

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。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

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。     

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

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.