SNAP PAC系统RS-485通信在水厂自控系统中的应用

结合美国OPTO 22公司的SNAP PAC系统,介绍了RS-485通信的实现及其在水厂自动化系统中的应用。实际运行结果表明,RS-485通信数据传输稳定可靠,能适应水厂具体的工艺环境,在水厂自动化系统中具有很好的推广应用前景。     

GPRS通信技术在供水工程中的应用

GPRS通信技术为水利远程测控系统的数据传输提供了一种新的手段.唐山市海港开发区供水(二期)工程采用GPRS通信数据传输技术可以对远程现场运行设备进行监视和控制,以实现水泵的启停、管道压力的自动控制,从而实现供水工程的现代化、信息化.     

基于串行端口的自定义协议的数据通信方式设计与实现

简要介绍了计算机通用的串行通信端口RS-232在数据通信中的引脚功能。在Delphi环境中利用第三方通信控件AdpCom Port设计了自定义通信协议方式下实现数据通信的方法。最后结合具体实例给出了数据通信的接收和发送数据的主要代码。实际运行结果证明,该种通信方式可以实时、安全、可靠地实现不同安全等级计算机的数据传输。     

GPRS无线通信远距离输水工程后备通道的探讨

以河北省南水北调配套远距离输水工程监测系统为例,探讨在现有光纤通信技术的基础上探索通过中国移动GPRS无线通信网络建立可靠无线通信备用通道的可能性,以便在光纤通信系统故障时,可以进行数据传输的无缝切换,保障自动化系统的通信传输畅通,确保监测系统的正常运行。     

水文仪器现状与发展（续三）

12 水文数据传输 为了及时、准确地获取有关的水文信息,需要布局合理、准确可靠的传输手段。当前,在水文数据传输上可以采用的通信方式很多,有必要根据各种情况、所处流域的特点加以考虑。12.1 短波通信12.1.1 概述 短波通信是用电离层的反射实现两地通信的,传输距离远,无需中断。同超短波水情     

大伙房长距离输水工程SCADA系统设计

大伙房水库输水二期工程自大伙房水库引水,通过隧洞和管道,采取封闭供水方式,向抚顺等6个城市供水,系统运行工况复杂,控制要求高.为实现工程全线设备的自动监测与控制,保证系统技术先进、运行稳定可靠,从计算机数据采集与监控(SCADA)系统的实现目标与功能、系统总体结构及主要设备配置、系统冗余策略、系统控制策略及方式、系统通信等方面进行了分析设计.系统建成后将为大伙房水库输水工程运行管理提供安全可靠、科学经济的技术手段.     

无人值守通信机房的远程监控系统

为满足对无人值守通信站运行管理的要求,提出了一种基于数字视频监控技术为平台、综合音频监听与双向对讲、火灾与断电报警、温湿度自动监测、电源遥控等现代应用技术于一体的机房远程监控系统。该系统利用微波通信系统的数据传输通道构成一个计算机通信网络系统,实现对机房环境的视频﹑声音﹑温湿度和通信系统设备运行状况的实时监控,可及时采用应急措施处理意外事故,从而极大地提高水利通信系统的管理水平。     

民兵水库除险加固工程水文自动测报系统设计

水情自动测报系统通信组网设计的目的是在系统的中心站与各送测站点之间提供可靠的数据通道,以构成水、雨情数据传输网络,完成水情信息传输的任务。文章对民兵水库建立水文自动测报系统的必要性、水文站网布设、系统分析、通信组网进行了分析。     

数字式电液调速器的通信协议转换

针对数字式电液调速器与监控系统的通信协议不一致，提出了一种用C语言编写协议转换程序来实现可编程逻辑控制器(PLC)调速器与监控系统通信的方法，并详细介绍了协议转换的原理、通信系统的硬件构成以及软件实现方法。通过现场的严格实验运行，证明了该方法具有通信可靠、效率高、投资少等优点。     

基于MODBUS-RTU协议的PLC多路数据采集系统

介绍了MODBUS-RTU通信协议在RS-485总线中的通信方式,提出基于MODBUS-RTU通信的数据采集系统,分析了采用ADAM-5510E/TCP数据采集器的原因,阐述了RS-485总线信号的衰减、噪声干扰、浪涌干扰的解决方法,并结合工程说明了数据采集层、可编程逻辑控制器(PLC)控制与显示层、数据传输层的实现,以及系统总召/轮询传感器数据的程序设计思路.该系统已经过2个汛期的考验,运行稳定.     

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.     

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.     

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。     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

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.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

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.