Leakage Rate Model of Urban Water Supply Networks Using Principal Component Regression Analysis

To analyze the factors affecting the leakage rate of water distribution system, we built a macroscopic "leakage rate–leakage factors"(LRLF) model. In this model, we consider the pipe attributes(quality, diameter,age), maintenance cost, valve replacement cost, and annual average pressure. Based on variable selection and principal component analysis results, we extracted three main principle components—the pipe attribute principal component(PAPC), operation management principal component, and water pressure principal component. Of these, we found PAPC to have the most influence. Using principal component regression, we established an LRLF model with no detectable serial correlations. The adjusted R2 and RMSE values of the model were 0.717 and 2.067, respectively.This model represents a potentially useful tool for controlling leakage rate from the macroscopic viewpoint.

Groundwater Leakage and River Runoff in a Catchment Influenced by Tectonic Movement

In order to clarify how groundwater leakage and river runoff occur in a catchment under tectonic movement, the water balance was estimated in the forested (88.3% in area) Oikamanai River catchment (area, 62.6 km2), Hokkaido, Japan. The catchment’s geology is early Miocene to Pliocene sedimentary bedrock of partly high permeability, accompanied by currently active faults. Daily evapotranspiration, E, in water balance was calculated by applying the one-layer model to meteorological data in the rainfall season of 2011 and 2012, with the topographic influence on heat balance of the catchment considered. The coupling with the short-term water balance method for river runoff events allows us to estimate groundwater leaking to the other catchments through the faults and bedrock. As a result, the leakage corresponded to 50% - 80% of effective rainfall (=P - E: P, rainfall) in 2011, whereas it was lower or negative in 2012. The estimate of leakage then included variability of ca. 80%. In 2012, shallow groundwater storage seems to retain high baseflow during non-rainfall.

Analysis of force and leakage in water hydraulic motor's piston pairs

The positive pressure between pistonwall and piston hole of inner curve water hydraulic motor’s piston pairs is analyzed.The flow field of the piston pairs is numerically calculated and analyzed by the use of computational fluid dynamics method.The pressure and velocity distribution of flow field at different clearance is analyzed in the paper.The results show that when the clearance is 4-8 μm,with the increase of clearance,the negative pressure and the velocity of piston chamber decrease significantly,the velocity and leakage flow of the clearance increase.However,when the clearance is 10 μm,the negative pressure and the velocity of plunger chamber increase suddenly.By comprehensive analysis,the cylinder annular clearance should be controlled to be near 8 μm.

Water Leakages in Public Water Supply System and How to Prevent Them

The article addresses the results of effective water losses prevention in public water supply systems, focusing on procedures for monitoring hidden leaks as the main part of losses and as the first step to control and prevent them. The described methodology has been applied based on a cross-border cooperation between twin capital cities Vienna and Bratislava in the Central Europe Region within the project deWaloP （Developing Water Loss Prevention） and adopted in Bratislava Water Company （BVS） in the Slovak Republic. The paper provides a complex of simple and easily available practices for analyses of water distribution measurements bringing essential information as to the necessity to use advanced procedures to actively reduce leakage. These practices involve minimum night flows analyses, hydrodynamic pressures analyses, pinpointing of water leakages by working with valves in the water network, the methodology of setting alarm limits for measured data, as well as use of advanced practices to obtain missing topologic data. As the water infrastructure in former socialistic countries are in bad technical condition and the lack of pertinent operational data is a significant obstacle to the application of a more sophisticated methodology based on GIS and other information systems, the procedures focus on using the most simple way to evaluate and control water losses. Finally, the introduction of described methodology in Bratislava Water Company after many years of unsuccessful effort even with expensive sophisticated leakage equipment brought positive outputs and the graph line of water losses level is finally going down. The use of expensive multi-correlating equipment together with human resources on the basis of implementing the above described leakage monitoring will subsequently become more effective, as it shall pinpoint major leakages, disclosure and removal of that shall significantly contribute to the effective reduction of water losses.

基于WaterGEMS的供水管网建模及爆管分析研究

利用WaterGEMS建模软件及某市高新区自来水公司收集到相关数据,研究分析城市供水管网爆管事故,利用黄金分割法研究漏失水量,通过建模与计算机技术相结合进行动态分析,比较建立管网微观模型能够较好预测出供水管网发生爆管事故位置及漏失水量.

Deep learning based water leakage detection for shield tunnel lining

Shield tunnel lining is prone to water leakage,which may further bring about corrosion and structural damage to the walls,potentially leading to dangerous accidents.To avoid tedious and inefficient manual inspection,many projects use artificial intelligence(Al)to detect cracks and water leakage.A novel method for water leakage inspection in shield tunnel lining that utilizes deep learning is introduced in this paper.Our proposal includes a ConvNeXt-S backbone,deconvolutional-feature pyramid network(D-FPN),spatial attention module(SPAM).and a detection head.It can extract representative features of leaking areas to aid inspection processes.To further improve the model's robustness,we innovatively use an inversed low-light enhancement method to convert normally illuminated images to low light ones and introduce them into the training samples.Validation experiments are performed,achieving the average precision(AP)score of 56.8%,which outperforms previous work by a margin of 5.7%.Visualization illustrations also support our method's practical effectiveness.

Tunnel SAM adapter:Adapting segment anything model for tunnel water leakage inspection

Water leakage inspection in the tunnels is a critical engineering job that has attracted increasing concerns.Leakage area detection via manual inspection techniques is time-consuming and might produce unreliablefindings, so that automated techniques should be created to increase reliability and efficiency. Pre-trainedfoundational segmentation models for large datasets have attracted great interests recently. This paper proposes a novel SAM-based network for accurate automated water leakage inspection. The contributions of thispaper include the efficient adaptation of the SAM (Segment Anything Model) for shield tunnel water leakagesegmentation and the demonstration of the application effect by data experiments. Tunnel SAM Adapter hassatisfactory performance, achieving 76.2 % mIoU and 77.5 % Dice. Experimental results demonstrate that ourapproach has advantages over peer studies and guarantees the integrity and safety of these vital assets whilestreamlining tunnel maintenance.

Movement characteristics of Karst water in a deep mining area

In order to study the movement characteristics of groundwater in a deep mining area and solve the dispute of the distri- bution rule of hydro-chemical zoning which is contradicted by lixiviation water zoning in a horizontal direction, we directed our attention to the source of deep groundwater, its seepage and hydro-chemical characteristics in a typical mining area. We used a neotectonic water-control theory, chemical and isotope methods, as well as a method for analyzing dynamic groundwater conditions. The results indicate that 1) Karst water in the deep and medium parts of this mining area is recharged by vertical leakage through neotectonic fractures rather than seepage along strata from subcrop parts or surrounding flows; 2) from surface to deep leakage paths, the variation in the types of chemical groundwater agrees with the normal lixiviation water distribution rule and the age of mixed groundwater increases; 3) the water-rich zones along neotectonic fractures correspond with water-diluted zones in a hori-zontal direction; 4) the leakage coefficient and water capacity of aquifers increases during the flow process of Karst water along the antidip direction (from west to east) and 5) Karst water in shallow mining areas forms a strong runoff belt along strikes and quickly dilutes the water from deep and medium mining areas. Overall, chemical and dynamic water characteristics actually agree with in terms of the entire consideration for differences in vertical leakage and abnormalities in the zone of water chemical distribution, along a horizontal runoff direction.

Seismic reliability analysis of urban water distribution network

An approach to analyze the seismic reliability of water distribution networks by combining a hydraulic analysis with a first-order reliability method （FORM）, is proposed in this paper. The hydraulic analysis method for normal conditions is modified to accommodate the special conditions necessary to perform a seismic hydraulic analysis. In order to calculate the leakage area and leaking flow of the pipelines in the hydraulic analysis method, a new leakage model established from the seismic response analysis of buried pipelines is presented. To validate the proposed approach, a network with 17 nodes and 24 pipelines is investigated in detail. The approach is also applied to an actual project consisting of 463 nodes and 767 pipelines. The results show that the proposed approach achieves satisfactory results in analyzing the seismic reliability of large-scale water distribution networks.

Seismic Reliability and Rehabilitation Decision of Water Distribution System

In order to evaluate the seismic reliability of water distribution system and make rehabilitation decisions correspondingly, it is necessary to assess pipelines damage states and conduct functional analysis based on pipe leakage model. When an earthquake occurred, the water distribution system kept serving with leakage. By adding a virtual node at the centre of the pipeline with leakage, an efficient approach to pressure-driven analysis was developed for simulating a variety of low relative scenarios, and a hydraulic leakage model was also built to perform hydraulic analysis of the water supply network with seismic damage. Then the mean-first-order-second-moment method was used to analyse the seismic serviceability of the water distribution system. According to the assessment analysis, pipes that were destroyed or in heavy leakage were isolated and repaired emergently, which improved the water supply capability of the network and would constitute the basis for enhancing seismic reliability of the system. The proposed approach to seismic reliability and rehabilitation decision analysis on water distribution system is demonstrated effective through a case study.

Laccase Immobilized on Mesoporous Silica Materials and Its Corrosion Inhibition Performance in Circulating Cooling Water System

Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.

Irish Water and Scottish Water: A Comparison

Rising costs of production and the need for capital investment in the public water supply network in Ireland, has placed a strong emphasis on the need for water conservation and tackling the current high levels of leakage (Department of the Environment, Community and Local Government, 2015) [1]. Consequently, Irish Water which is Ireland’s national water utility has had to consider various business models and supply frameworks to demonstrate value for money. This has included those successfully implemented by Scottish Water. Therefore, the aim of this study was to compare both national utility providers in terms of structure and financial performance. The results of this study showed that both utility providers differed significantly. The Utility has, indeed, tried to achieve “too much too soon” (O’Leary, 2018 [2];Donegal Now, 2016) [3]. Therefore, the initial results of this study suggest that, continuing to consider Scottish Water as the benchmark may generate unrealistic targets and expectations which in all probability may not be achieved.

Empowering Conditions for Good Water Governance-a Sustainable Model： Vilanculos Case Study （Mozambique）

This article shows the results of the project Empowering conditions for good water governance-a sustainable model： Vilanculos case study （Mozambique）, co-financed by the European Community. This project had the aim of improving sanitary conditions and increasing economic and financial sustainability of water services for the population of Vilanculos. The project has been developed and deployed with cooperation between Acque del Chiampo （an Italian water utility, near Vicenza）, the University of Brescia and the Vilanculos public water service utility, Empresa Mo^ambicana de Agua （EMA）. The paper reports analytical praxis for water distribution measurements, capable of providing essential data about the water network performances, to assess the eventual need for actions in order to solve possible and effective problems of the water service. These practices involve flow and pressure analyses, pinpointing of the network＇s criticalities and leakages by in-situ inspections along the network, managing the valves together with water service utility, as well as the use of a water distribution model to simulate the effects of the proposed interventions and specific software to automatically register bills and payments.

西南岩溶区水土漏失研究进展与展望

水土漏失是岩溶区特有的水土流失问题,自21世纪以来才逐步开展研究与防治工作。本文在系统分析把握已有相关研究进展的基础上,阐明西南岩溶地区水土漏失的特点,揭示以岩溶地下河流域为单元开展水土漏失过程系统研究的重要性,总结水土漏失监测评价和影响因素等方面的研究进展。指出目前的水土漏失研究在岩土缝组构刻画、水土漏失关键过程和机制、水土漏失评价模型等方面存在不足。面向西南岩溶区水土漏失防治的国家目标和国际前沿研究方向,提出下一步应开展岩溶关键带水土漏失网络研究、水土漏失关键过程系统研究、以及水土漏失评价模型构建和应用3个重要方向的工作。

隧道拱顶渗漏稳态渗流场的解析研究

针对隧道运营中发生拱顶渗漏且无泥沙涌入的稳态渗流情况,结合保角变换法和分离变量法推导出隧道拱顶渗漏稳态渗流场的显式解析解.应用PLAXIS有限元软件建立数值模型,从渗流场分布、衬砌水压力两方面验证所得解的正确性,通过与现有解析解、数值解、试验结果的渗流量对比来验证所得解的准确性.进行参数分析,探究隧道埋深、渗漏宽度对衬砌水压力和渗流量的影响规律.结果表明,衬砌水压力在以渗漏位置为中心±60°范围内明显降低;随着隧道埋深的增大,衬砌最大水压力减小,渗流量先减小后增大,且渗流量最小值对应的隧道埋深随着地表水头的增大而增大;随着渗漏宽度的增大,衬砌最大水压力减小,渗流量增大,当渗漏宽度大于0.05 m时,渗漏宽度变化对水压力和渗流量的影响较小;在渗漏宽度较小时进行渗漏控制的效果明显.

改进Mask RCNN的盾构隧道渗漏水检测方法

渗漏水是盾构隧道结构存在潜在损伤或缺陷的重要表征,快速、准确检测出渗漏水位置,对隧道安全运营和维护具有重要意义。现有的方法大多采用光学影像对隧道渗漏水进行检测,受隧道内空间和光线条件限制,难以获得高质量病害图片。因此,本文提出了一种基于激光点云数据与改进Mask RCNN相结合的渗漏水检测方法。首先对激光点云反射强度进行修正;然后生成灰度图像并建立渗漏水病害数据集;最后在Mask RCNN算法中引入空洞卷积和变形卷积,实现了隧道渗漏水病害的快速检测。利用某地铁采集的数据进行验证,结果表明,本文提出的改进Mask RCNN算法相较于原始算法和FCN算法检测精度均有明显提升,在盾构隧道渗漏水识别方面性能表现较好。

锅炉水冷壁管失效分析

锅炉水冷壁管材料为20G钢,在320℃和10.3 MPa下使用约5年后外表面出现鼓包并泄漏。对失效的水冷壁管进行了宏观检查、化学成分分析、力学性能检测、金相检验、腐蚀产物分析及锅炉水质检测。结果表明:水冷壁管失效是由于锅炉水碱性超标从而发生高温碱腐蚀所致。

育肥猪智能饮水碗设计与性能测试

饮水量及饮水的质量是影响猪只生长和健康的重要因素,研制新型猪只节水清洁型智能饮水设备对猪舍管理和提高动物福利具有重要意义。该研究对传统碗式饮水器进行了改进,研制了一种猪只智能节水型饮水碗,探究了智能饮水碗在猪只生产性能、用水量、饮水行为和碗内饮用水卫生指标方面的应用效果。试验选取100头体质量为(85.87±15.80)kg的育肥猪,随机分为2个处理组,饮水设备分别采用传统饮水碗和智能饮水碗,每个处理组5个重复,每个重复10头猪,试验期为35 d。结果表明,2种饮水碗对育肥猪的生产性能(日增质量、日采食质量和料肉比)和饮水行为(饮水次数、饮水时长)无显著影响。传统饮水碗组和智能饮水碗组育肥猪的日均用水量分别为(11.14±0.46)、(10.05±0.46)L/d,两者存在极显著差异(P<0.01);浪费水量分别为(0.89±0.13)、(0.25±0.11)L/d,两者存在极显著差异(P<0.01);育肥猪使用智能饮水碗的用水浪费率相比传统饮水碗降低了60.9%~79.5%。传统饮水碗组和智能饮水碗组育肥猪的碗内余水总大肠菌群分别为(83.00±3.46)、(68.33±4.04)MPN/100 mL,两者存在极显著差异(P<0.01)。育肥猪使用智能饮水碗的碗内余水总大肠菌群与传统饮水碗相比降低了16.3%~19.2%。该智能饮水碗能有效保障猪只饮水健康和生长需求,减少猪只饮水浪费,降低碗内余水总大肠菌群数量,提高动物福利水平。研究可为养殖场节水减排提供理论依据及技术支撑。

基于三维激光扫描技术的竣工盾构隧道渗漏水检测

渗漏水是隧道常见的病害,长期渗漏会导致隧道结构开裂、裂缝、钢筋腐蚀,威胁到隧道运营安全,因此对其检测一直受到重视。本文利用三维激光扫描技术实现了竣工盾构隧道渗漏水的位置及面积的自动检测。首先采用架站式三维激光扫描仪采集竣工隧道点云,基于修正后的反射强度值生成隧道衬砌表面灰度图,再采用膨胀法与腐蚀法对灰度图像进行预处理;然后利用连通域算法计算渗漏水位置及其面积;最后结合实际工程验证本文方法的实用性及准确性。结果表明,应用本文方法竣工隧道的渗漏水检测准确率达92%。

基于一元线性回归模型的供水网络中水表读数虚高问题研究

为了定量研究供水网络中总表漏水程度和分表读数虚高程度,根据水量平衡分析法的原理,结合大数据分析技术,建立了一元线性回归方程,回归常数代表总表漏水量程度,回归系数代表分表读数虚高程度。通过针对2021年某高校供水管网的实证研究表明,总表日均漏水量为15.5958吨,分表读数虚高率为1.07%。该方法对供水管网漏损率的精准评估等问题的解决提供了新的思路和方法。