Water Leakage Research Articles

All-in-one-piece type prosthesis combining an obturator, a facial prosthesis, and glasses for the rehabilitation of midfacial defect and its speech evaluation: A clinical report

This case report describes the use of an all-in-one-type prosthesis that combines an obturator, a facial prosthesis, and glasses in a 70-year-old man with a mid-facial defect caused by oral squamous cell carcinoma. The patient had undergone maxillary resection and postoperative recovery with an obturator; however, slurred speech, water leakage from the nose, and aesthetic issues persisted. The all-in-one-type prosthesis was designed to improve speech and aesthetics by connecting the obturator and facial prosthesis with a magnet and connecting the epithese to the glasses. The prosthesis was fabricated by a dental technician, who created a wax pattern of the epithese directly on the patient's face and used it to fabricate a custom-made epithelial prototype. The final prosthesis was fitted and adjusted for optimal position and comfort. The improvement in speech function was evaluated via formant analysis and nasalance evaluation and found to be satisfactory. (Int J Maxillofac Prosthetics 2023;6:20-24)

Flow forecasting for leakage burst prediction in water distribution systems using long short-term memory neural networks and Kalman filtering

Reducing pipe leakage is one of the top priorities for water companies, with many investing in higher quality sensor coverage to improve flow forecasting and detection of leaks. Most research on this topic is focused on leakage detection through the analysis of sensor data from district metered areas (DMAs), aiming to identify bursts after their occurrence. This study is a step towards the development of ‘self-healing’ water infrastructure systems. In particular, machine learning and deep learning-based algorithms are applied to forecasting the anomalous water flow experienced during bursts (new leakage) in DMAs at various temporal scales, thereby aiding in the health monitoring of water distribution systems. This study uses a dataset of over 2,000 DMAs in North Yorkshire, UK, containing flow time series recorded at 15-minute intervals for a period of one year. Firstly, the method of isolation forests is used to identify anomalies in the dataset, which are cross referenced with entries in the water mains repair log, indicating the occurrence of bursts. Going beyond leakage detection, this research proposes a hybrid deep learning framework named FLUIDS (Forecasting Leakage and Usual flow Intelligently in water Distribution Systems). A recurrent neural network (RNN) is used for mean flow forecasting, which is then combined with forecasted residuals obtained through real-time Kalman filtering. While providing expected day-to-day flow demands, this framework also aims to issue sufficient early warning for any upcoming anomalous flow or possible leakages. For a given forecast period, the FLUIDS framework can be used to compute the probability of flow exceeding a pre-defined threshold, thus allowing decision-making for any necessary interventions. This can inform targeted repair strategies that best utilize resources to minimize leakages and disruptions. The FLUIDS framework is statistically assessed and compared against the state-of-practice minimum night flow (MNF) methodology. Based on the statistical analyses, it is concluded that the proposed framework performs well on the unobserved test dataset for both regular and leakage water flows.

Comparative Study of Leak Detection in PVC Water Pipes Using Ceramic, Polymer, and Surface Acoustic Wave Sensors.

The detection and location of pipeline leakage can be deduced from the time arrival leak signals measured by acoustic sensors placed at the pipe. Ongoing research in this field is primarily focused on refining techniques for accurately estimating the time delays. This enhancement predominantly revolves around the application of advanced signal processing methods. Additionally, researchers are actively immersed in the utilization of machine learning approaches on vibro-acoustic data files, to determine the presence or absence of leaks. Less attention has been given to evaluating the sensitivity, performance, and overall effectiveness of these sensors in leak detection; although acoustic methods have been successfully used for leak detection in metallic pipes, they are less effective in plastic pipes due to the high attenuation of leak noise signals. The primary thrust of this research centers on identifying sensors that not only possess sensitivity but also exhibit high efficiency. To accomplish this goal, we conducted an exhaustive evaluation of the performance of three distinct categories of acoustic sensors employed for detecting water leaks in plastic pipes: specifically, lead zirconate titanate (PZT) sensors, polyvinylidene fluoride (PVDF) sensors, and surface acoustic wave (SAW) sensors. Our evaluation encompassed the performance of PVDF and SAW sensors in leak detection, comparing them to PZT sensors under a variety of conditions, including different leak sizes, flow rates, and distances from the leak. The results showed that all three sensors, when they were placed in the same position, were able to detect water leaks in plastic pipes with different sensitivities. For small leaks (1 mm, 2 mm), the PVDF sensor showed the greatest sensitivity (0.4 dB/L/h, 0.33 dB/L/h), followed by the SAW sensor (0.16 dB/L/h, 0.14 dB/L/h), and finally the PZT (0.13 dB/L/h, 0.12 dB/L/h). Similarly, for larger leaks (4 mm, 10 mm), the PVDF sensor continued to show superior sensitivity (0.2 dB/L/h, 0.17 dB/L/h), followed by the SAW sensor (0.13 dB/L/h, 0.11), and finally the PZT sensor (0.12 dB/L/h, 0.1 dB/L/h), outperforming the PZT sensor. This suggests that SAW and PVDF sensors, have the potential to serve as valuable, cost-effective alternatives to traditional commercial leak noise transducers. The outcomes of this comparative study involving three acoustic sensors hold the potential to advance the development of robust and dependable systems for the detection of water leaks in plastic pipelines.

Three-dimensional numerical research on coupling heat transfer characteristics of PRHR HX under different water levels based on the experimental model

The passive residual heat removal system (PRHRs) is an important heat transfer system to ensure the removal of residual heat in non-LOCA conditions occurring in advanced Generation III nuclear reactors. The water level of the In-containment Refueling Water Storage Tank (IRWST) decreases due to long-term water evaporation under accident conditions and the later stages of PRHRs operation. Additionally, the water level also decreases during the water leakage accidents. The reduction of water level contributes to a decrease in the heat transfer area and the passive residual heat removal ability of the core. In order to investigate the coupling heat transfer characteristics of both primary and secondary side in the heat exchanger under different water levels, Three-dimensional numerical simulations of the PRHR HX's operation under different water levels was carried out based on the scaled-down IRWST&PRHR HX experimental model. The fluid flow and heat transfer processes inside and outside the C-type tubes were analyzed in detail. The results indicate that when heat transfer area is reduced by 50%, the overall heat transfer rate is reduced by about 41%, meanwhile the average heat transfer coefficient is about 37.4% higher than that under the full water level condition. It indicates that PRHR HX can maintain high passive residual heat removal capacity even under half water level, which provides an important reference for the design and safe operation of the PRHR HX.

Analytical model for the sealant performance of tunnel gasketed joints based on multi-scale contact and percolation theories

The localised leakage in shield tunnels that mainly occurs at segment joints may induce other defects, which threatens operational safety. To obtain a universal solution for the sealant performance of gasketed joints, we proposed a novel analytical model based on the multiscale contact and percolation theories, in which the obtained percolation pressure and interfacial separation can be utilized to derive the critical water leakage pressure and leakage rate. The evolutionary process of leakage was divided into three stages (i.e., the percolation, leakage and breakdown), which explicitly reveal the progressive hydraulic deterioration of gasketed joints. The gaskets still own partial waterproof capacity until the end of the leakage stage due to the remaining contact pressure at surface asperities. The proposed model was first verified by several sets of experimental data, based on which the determination of three key model parameters (i.e., self-sealing slope, sealing coefficient, and expel pressure) were discussed in detail. The parametric study indicates that the waterproof capacity is significantly affected by the joint opening, offset, and the surface roughness of the gaskets. The variation in waterproof capacity with joint opening is mainly due to the nonlinearity of the gasket’s modulus and self-sealing slope. The increase in joint offset can result in a lower waterproof capacity as well as a larger leakage rate. Gasket’s surface roughness affects the percolation pressure and interfacial separation, which contributes to the long-term sealant performance.

Detection of water leakage defects in cable insulation sheath based on terahertz time-domain spectroscopy

Water leakage of the insulation sheath can lead to a decrease in the insulation performance of the power cable, which poses a hidden danger to the power cable. Accurate detection and positioning of the water leakage area are crucial for improving power safety and stability. In response to the water leakage defect of the cable insulation sheath, this article proposes a method based on reflective terahertz time-of-flight tomography technology to measure the water leakage area of the insulation sheath. A sample of insulation sheath water leakage defect was prepared by simulating real scenarios. By analysing the terahertz reflection time-domain optical spectrum and imaging results of the sample, the location and area of the insulation sheath water leakage defect can be accurately measured, verifying the application potential of reflective terahertz time-of-flight tomography technology in detecting water seepage defects in cable insulation sheaths.

The Utility of Water Leak Test in Evaluating the Functionality of Sterilization Containers

The Utility of Water Leak Test in Evaluating the Functionality of Sterilization Containers

A Novel Technique for Detecting Underground Water Pipeline Leakage Using the Internet of Things

Water-pipeline leakage is one of the most common problems that depletes water supplies. Countries like Jordan, which are really experiencing a water deficit, are particularly concerned about this issue. The lack of monitoring tools makes the underground water-pipeline leakage a challenge since the pipelines are invisible. Besides, reducing the amount of time needed to precisely detect and locate the leak is another challenge. If not reduced, the aforementioned element has an effect on cost. A small broken water distribution line costs $64,000 per year. In Jordan, water leakage costs $1.7 million. This expense can be significantly decreased using an effective early water leak detection system. In this paper, we proposed an efficient internet of things system for detecting water-pipeline leakage based on a shielded pipeline, a NodeMCU, a soil moisture sensor, and the Firebase database. We created a baseline system, and then we tested and evaluated the proposed system when various types of soil are used. Furthermore, this paper compared several strategies offered for detecting water-pipeline leaking including the proposed system. The results showed that the proposed system reduced the time required for detecting water-pipeline leakage by 70% and the system hardware cost by 83% compared with the earlier work. It was difficult to compare the total cost of the proposed system with the total cost of previous works since the total cost is not calculated in their systems.  Besides, in this paper, we proposed an IoT system for securing the underground water pipelines from adversaries.

Hidden risks: Simulated leakage of domestic sewage to secondary water supply systems poses serious microbiological risks

There are continuous reports about the pollution of the secondary water supply systems (SWSSs), among which domestic sewage leakage is the most serious. In this study, a pilot experiment lasting 70 days was conducted to explore the changes in physicochemical water quality and the microbial profiles in SWSSs polluted by different doses of domestic sewage through qPCR and high-throughput sequencing methods. The results showed that when domestic sewage entered the simulated water storage tank, a large amount of organic matter brought by domestic sewage quickly consumed chlorine disinfectants. High pollution levels (pollution index ≥ 1/1000) were accompanied by significant increases in turbidity and ammonia nitrogen concentration (p < 0.05) and by abnormal changes in sensory properties. Although different microbial community structures were found only at high pollution levels, qPCR results showed that the abundance of the bacterial 16S rRNA gene and some pathogenic gene markers in the polluted tank increased with the pollution level, and the specific gene marker of pathogens could be detected even at imperceptible pollution levels. In particular, the high detection frequency and abundance of Escherichia coli and Enterococcus faecails in polluted tank water samples demonstrated that they can be used for early warning. Moreover, it seems that the microorganisms that came with the domestic sewage lost their cultivability soon after entering SWSSs but could recover their activities during stagnation. In addition, the biofilm biomass in the polluted tank with high pollution levels increased faster at the initial stage, while after a longer contact time, it tended to remain at the same level as the control tank. This study emphasized the high microbial risk introduced by sewage water leakage even at imperceptible levels and could provide scientific suggestions for early warning and prevention of pollution to SWSSs.

Experimental Analysis of Watertightness Performance of Interfaces between Masonry and Steel Structures Subjected to Accelerated Aging

Steel buildings often experience failure at the interfaces between their vertical exterior enclosure systems (VEESs) and structural elements. This phenomenon generates various pathological manifestations in steel buildings, resulting in the precocious decay of the structure and the diminishment of its service life. The treatment of these interfaces is essential for ensuring their proper performance and watertightness, and to protect the durability of the steel structure. This paper proposes a method for treating common interface joints between masonry and steel structures with the application of an EPDM (ethylene propylene diene monomer) elastomer membrane. The main goal of this building technique is to ensure the durability and watertightness of the interface’s joints when they are subjected to aging triggered by heat exposure and thermal shock. The experimental models tested consisted of a steel frame and a conventional masonry vertical enclosure system with ceramic blocks plastered with cement mortar. The models were subjected to ten cycles of heat exposure and thermal shock for the purpose of simulating accelerated aging, followed by a watertightness experiment that simulated the action of both rain and wind pressure. The interfaces between masonry and the steel structure proposed in this study allowed adequate differential movements between the parts, without damage to joints and masonry. Only small cracks were observed in the outer test region of all of the interfaces tested. In the regions of the joints treated with the EPDM membrane, no alterations were visible to the naked eye. During the cycles of the heat exposure and thermal shock test, the maximum relative horizontal displacements observed in the joints were 0.743 mm for vertical joints and 0.230 mm for horizontal joints, indicating the accurate reproduction of the behavior expected from an untied interface. The results obtained in the previously mentioned watertightness test showed that no humidity stains were found on the inner face of any of the specimens, even after the continuous application of a pneumatic pressure of 400 Pa for eight hours. Therefore, the results indicated satisfactory performance in terms of durability and watertightness in all evaluated cases, indicating that the application of an EPDM membrane can be effective in preventing water leaks in the interfaces between masonry and steel elements, thus contributing to ensuring the steel structure’s durability.

Technologies for large cross-section subsea tunnel construction using drilling and blasting method

This paper reviews the progress made by our research team in the construction of large cross-section subsea tunnels using the drilling and blasting method. Our research on the prevention and control of water inrush during the construction period and the control of water leakage and discharge during the operational period is introduced. It includes a compound grouting technology for high permeable ground, an elaborate process control method for large cross-section tunnels and an active controlling waterproof-drainage system. These achievements were applied to the first two large cross-section subsea tunnels in China, namely the Xiamen Xiang’an Tunnel and the Qingdao Jiaozhou Bay Tunnel. Thereafter, the technical mode of subsea tunnel construction using the drilling and blasting method was established, providing a theoretical basis and systematic technical support for the safe construction of large cross-section subsea tunnels under complex conditions.

Statistical parametric and non-parametric control charts for monitoring residential water consumption

The adoption of strategies for monitoring water consumption is essential for water resources management, contributing to the promotion of the sustainability in the water sector. Statistical process control (SPC) charts, which are widely used in the industrial sector, are statistical methods developed to improve the quality of products and processes. The application of this method has reached other areas over the last decades and has recently been identified as an option for environmental monitoring. In this context, the application of SPC charts emerges as an option for water consumption monitoring, whether in a building or an urban scale. Thus, this article aims to analyze the application of statistical process control charts in the monitoring of water consumption of two housing compounds in Joinville, southern Brazil. The methodological procedures include the use of the Shewhart and the EWMA control charts in addition to the non-parametric alternative, the EWMA-SN, assessing the effectiveness of these techniques in detecting water leaks in residential apartment buildings. The data sets, obtained through a telemetry metering system from the water utility, represent a period of 243 days. The results show that control charts are a powerful tool in identifying changes in water consumption patterns, with the EWMA chart flagging the leaks sooner.

Damage Mechanism of Copper Cooling Plate on Large Blast Furnace

This work investigates the application of cooling plate in a 4500 m3 blast furnace in China. Scanning electron microscopy–energy dispersive X‐ray spectroscopy and an optical microscope are used to examine the affected area. The results demonstrate that using a cooling plate in a huge blast furnace has a positive effect, notably in furnace belly and bosh, where the damage rate is less than 3%. While the cooling plates in the middle shaft are more severely damaged, with a damage rate of up to 55.40%. The majority of the copper cooling plate's damage is centered in the water channel area, where there are furrows and numerous microcracks on the damaged surface, as well as a tiny quantity of metallurgical slag attached. Cracks form on both the inside and outside of the water channel, and the grains surrounding the cracks rise significantly, which is the primary cause of the cooling plate's water leaking. The main factor of cooling plate damage in the early stage is wear, and the cracking caused by force in the later stage. The use of a copper cooling plate from the furnace bosh to the lower shaft is preferable to the use of a copper cooling stave.

Enhancing Urban Surface Runoff Conveying System Dimensions through Optimization Using the Non-Dominated Sorting Differential Evolution (NSDE) Metaheuristic Algorithm

Rapid urban development and increase in construction have significantly altered the surface coverage of cities, resulting in a rise in impervious surfaces such as roofs, streets, and pavements. These changes act as barriers against rainwater infiltration into the soil, leading to a substantial increase in surface runoff. Managing surface runoff has become a critical task in civil engineering and urban planning, as it can mitigate damage and provide opportunities for utilizing excess water. However, traditional flood control and guidance systems tend to be extensive and expensive, prompting researchers to explore cost-effective alternatives that consider all design parameters and variables. In this research, we propose an innovative approach that combines the NSDE (non-dominated sorting differential evolution) metaheuristic algorithm as an optimizer with the SWMM (storm water management model) as a simulator. The objective is to design efficient surface runoff collection networks by thoroughly investigating their hydraulic behaviors. This study focuses on the Chitgar watershed in Tehran, Iran, utilizing the SWMM model and NSDE multi-objective metaheuristic algorithm to determine the optimal dimensions of the channel and its intersecting structures. The aim is to minimize costs and reduce water leakage from the network. A comparison is made between the optimized design results and the existing network plan (without any design modifications). The analysis reveals substantial reductions in water leakage for all three design scenarios: a 7.66% reduction when considering only bridges, a 7.35% reduction with only the canal, and an impressive 95.26% reduction when both the canal and bridges are incorporated. These findings demonstrate the superiority of the optimized designs in terms of cost-effectiveness and the efficient management of surface runoff.

Automatic Detection and Association Analysis of Multiple Surface Defects on Shield Subway Tunnels.

The surface defects on a shield subway tunnel can significantly affect the serviceability of the tunnel structure and may compromise operation safety. To effectively detect multiple surface defects, this study uses a tunnel inspection trolley (TIT) based on the mobile laser scanning technique. By conducting an inspection of the shield tunnel on a metro line section, various surface defects are identified with the TIT, including water leakage defects, dislocation, spalling, cross-section deformation, etc. To explore the root causes of the surface defects, association rules between different defects are calculated using an improved Apriori algorithm. The results show that: (i) there are significant differences in different association rules for various surface defects on the shield tunnel; (ii) the average confidence of the association rule "dislocation & spalling → water leakage" is as high as 57.78%, indicating that most of the water leakage defects are caused by dislocation and spalling of the shield tunnel in the sections being inspected; (iii) the weakest rule appears at "water leakage → spalling", with an average confidence of 13%. The association analysis can be used for predicting the critical defects influencing structural reliability and operation safety, such as water leakage, and optimizing the construction and maintenance work for a shield subway tunnel.

A nature-based solution to reduce soil water vertical leakage in arid sandy land

Quick water seepage in sandy soils results in a serious restriction for ecological restoration, becoming a worldwide urgent research issue in arid areas. Search for practical solutions are focused on reserving the limited rainfall into topsoil layer to meet plant water demand. Based on fieldwork, this study evaluates the blocking effects of Pisha sandstone on soil water leakage, by inserting sandstone layers in the different soil depths (10–15 cm, 20–25 cm, 30–35 cm), which act as isolation layers within the sandy soil. Results showed that the inserted Pisha sandstone layers significantly decreased the soil water infiltration rates at the different stages and cumulative infiltration. The inserted sandstone layer at the depth of 10–15 cm presented the highest permeability resistance, and its initial infiltration rate, stable infiltration rate and average infiltration rate decreased by 102.42 mm h−1, 144.30 mm h−1 and 132.79 mm h−1, respectively. Meanwhile, the soil water content in the 5–10, 20–25, and 30–35 cm soil layers increased by 2.17%, 2.20%, and 1.37%, respectively, due to the inserted Pisha sandstones. This experimental study proves that the insertion of Pisha sandstones effectively hinders the downward penetration of soil water in sandy soil. These findings provide a new alternative for an effective solution of the fast water leakage problem of sandy land.

HYPER: Computer-Assisted Optimal Pump-as-Turbine (PAT) Selection for Microhydropower Generation and Pressure Regulation in a Water Distribution Network (WDN)

Although pressure reducing valves (PRVs) have traditionally been employed to regulate pressure and reducer water leakage, researchers have been increasingly investigating the strategy of micro-hydropower generation using pumps as turbines (PATs) to enable both pressure reduction and energy production as an alternative strategy in water distribution networks (WDNs). However, due to the continuous variability of flow discharge during the day, selecting the optimal PAT remains a challenging issue. To address this, the authors have developed HYPER, a freely available software app that implements an innovative approach for selecting the most suitable PAT in systems that involve both hydraulic and/or electrical regulation. In enabling the identification of the PAT parameters that maximize energy production, HYPER thus provides a fast and effective PAT selection tool. The effectiveness of the proposed approach was further demonstrated with application to a real WDN. Four operational patterns varying in terms of available flow and head drop were considered, showing that the most efficient pumps consistently tended to be located in close proximity to the maximum produced energy. Furthermore, the results confirmed that hydraulic regulation and coupled hydraulic/electric regulation-based installation layouts represent the best solutions in terms of energy produced. The solely electrical regulation option, given its poor flexibility, returns in all cases lower energy production with the lower adaptability of commercial pumps.

Water Flow Modeling and Forecast in a Water Branch of Mexico City through ARIMA and Transfer Function Models for Anomaly Detection

Early identification of anomalies (such as leakages or sensor failures) in urban water distribution systems is critical to mitigating water scarcity in cities and is a challenge in water resource management. Several data-driven methods based on machine learning algorithms have been proposed in the literature for leakage detection in urban water distribution systems. Still, most of them are challenging to implement due to their complexity and requirements of vast amounts of reliable data for proper model generation. In addition, the required infrastructure and instrumentation to collect the data needed to train the models could be unaffordable. This paper presents the use and comparison of Autoregressive Integrated Moving Average models and Transfer Function models generated via the Box–Jenkins approach to modeling the water flow in water distribution systems for anomaly detection. The models were fit using water flow data from tanks operating in a branch of the water distribution system of Mexico City. The results showed that both methods helped select the best model type for each variable in the analyzed water branch, with Seasonal ARIMA models achieving a lower mean absolute percentage error than the fitted Transfer Function models. Furthermore, this methodology can be adjusted to different time windows to generate alerts at different rates and does not require a large sample size. The generated anomaly detection models could improve the efficiency of the water distribution system by detecting anomalies such as wrong measurements and water leakages.

Acoustic signal based water leakage detection system using hybrid machine learning model

ABSTRACT Water supply pipeline leakage is a major issue around the world. Leak detection and remediation can prevent water scarcity and some other problems. As a result, investigating pipeline leak-detecting technology has a high practical value. This study employs a promising technique for detecting pipeline leaks using Acoustic Emission (AE) signals. A dytran acceleration sensor was used to collect leakage signals in the time domain. The time-domain signal is transformed into a frequency domain by employing Fast Fourier Transform (FFT). The produced frequency signal has many dimensions which can be reduced to 17 by Principal Component Analysis (PCA). Intelligent leakage diagnosis techniques should eliminate time, and human intervention, and increase effectiveness. Machine learning (ML) models come into play at this point. To detect leakage, the hybrid ML model is proposed and it is compared with the conventional ML models. The best model for detecting water leakage is identified using the classification metrics.

Applying Plaxis 3D To Model Leaking Water Supply Pipe Causing Sandy Soil Erosion and Sinkhole Formation

Water supply pipes in urban areas are always buried underground. There are many causes of pipe breakage and leakage of high-pressure water from the pipe to the outside, the flow of water has a pressure higher than the soil erosion limit, causing the soil structure to be broken, eroding the surrounding clayey sandy soil. The development of the eroded clayey sandy soil area, which expands over time, is the cause of the formation of a sinkhole under the road, which is dangerous for vehicles and people. In this study, the authors apply finite element software (Plaxis 3D) to model water supply pipelines in sandy soil in case the pipeline leaks water with different pressures. Analytical models indicate that sinkhole formation is dependent on the extent of the erosive clayey sandy soil, which is related to the extent and direction of the pressurized water jet, and the depth of the pipe.