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The paper proposes a novel methodology to locate and quantify entrapped air pockets created during pipe-filling events often found in intermittent water supply systems. Different filling conditions were tested in an experimental pipe with a high point. Measurements were taken and video recordings were carried out to assess air pocket volumes for different air release conditions at the downstream end of the pipe. The stochastic nature of air pocket creation resulted in varying air volumes. A new numerical model capable of simulating the air pocket creation, dragging and entrainment has been proposed. The new model, AirSWMM, was implemented as an extension of the Stormwater Management Model (SWMM) with stochasticity of air pocket formation reproduced by simulations with different air entrainment rates. The obtained numerical results show that the proposed model, even though based on a single-phase one-dimensional flow, can accurately locate and approximately quantify the entrapped air pocket volumes., Sanitary Engineering

Intermittent water supply systems are prone to air entrapments during the pipe filling phase. This work aims to analyse and discuss the numerical results obtained by applying the recently developed AirSWMM model, an extension of SWMM incorporating air phase, to a laboratory network. Experimental data consisting of pressure-head at multiple locations and video recordings of air entrapments are collected in a single loop network with a high point, for different pipe-filling conditions, system layouts and node elevations. Experimental tests have shown that the air entrapment occurred not only at the high point but also throughout the pipe network, creating air pockets with elongated shapes and larger volumes than for single pipes. AirSWWM model with air-entrapment formation, growth and transport is tested in the pipe network, and results are compared with measurements. AirSWWM model can correctly locate large air pockets but underestimates their volume., Education AE, Sanitary Engineering

The ambient noise in water pipelines are observed as spontaneous signal sources that can be used for pipe fault detection by correlation analysis. However, the limited bandwidth of these noise signal causes strong correlation sidelobes, which introduces significant ambiguities when extracting the system response from correlation results and this increases the risk of false alarms from fault detections. This paper proposes a compressive sensing based method that can extend the noise bandwidth and suppress the correlation sidelobes. Numerical and field experiment results have shown that with the recovered wider bandwidth, the correlation sidelobes can be significantly suppressed and the pipe faults can be identified with greater certainty. The impacts of fault size as well as noise bandwidth, strength and spectrum features on the proposed method are also assessed through numerical experiments. © 2023 Elsevier Ltd

A passive detection method has been proposed in a prior paper to extract key parameters and detect faults using the ambient noise present in water pipeline networks. This paper presents field experiments and data processing results to provide systematic experimental validation of this method. Field experiments were carried out in operational water pipeline networks at the University of Canterbury campus and the Waimakariri District, New Zealand, during which ambient noise was measured by pairs of pressure sensors installed at selected hydrants on pipelines of different materials, network topologies and simulated faults. Auto-correlation and cross-correlation analysis of noise at a single sensor and sensor pairs were carried out to estimate the wave speed and to locate faults in the networks. Data processing results indicate that water usage generating pressure transients are the dominant sources of ambient noise in operational water pipeline networks. This type of ambient noise can also be utilized by the passive detection method to achieve similar wave speed estimation accuracy and fault detection performance as the conventional active pressure wave detection methods. © 2022 Elsevier Ltd

Ambient noise generated by flowing water turbulence is harnessed as a signal source for imaging key parameters and fault detection in water pipelines. This approach is important because it can aid in the estimation of wave speed or detection of water pipeline defects such as blockages and leakages. More importantly it overcomes the challenging problem of generating a signal source of sufficient power to provide the necessary signal-to-noise ratios for conventional water pipeline imaging and fault detection techniques. In this paper, the expressions of the auto- and cross-correlation functions of the ambient noise between sensors are derived using wave theory. It is shown that the time-domain Green's functions can be extracted from the correlation functions. Experimental and numerical examples are provided for water pipelines to demonstrate that wave speed can be estimated from the time-domain Green's functions. A method for extending the technique, by using straightforward but accurate approximations of the correlation functions, to detect the presence of defects in the profile of the water pipeline is also proposed.

Ambient noise generated by flowing water turbulence is harnessed as a signal source for imaging key parameters and fault detection in water pipelines. This approach is important because it can aid in the estimation of wave speed or detection of water pipeline defects such as blockages and leakages. More importantly it overcomes the challenging problem of generating a signal source of sufficient power to provide the necessary signal-to-noise ratios for conventional water pipeline imaging and fault detection techniques. In this paper, the expressions of the auto- and cross-correlation functions of the ambient noise between sensors are derived using wave theory. It is shown that the time-domain Green's functions can be extracted from the correlation functions. Experimental and numerical examples are provided for water pipelines to demonstrate that wave speed can be estimated from the time-domain Green's functions. A method for extending the technique, by using straightforward but accurate approximations of the correlation functions, to detect the presence of defects in the profile of the water pipeline is also proposed.

Text-to-speech and co-speech gesture synthesis have until now been treated as separate areas by two different research communities, and applications merely stack the two technologies using a simple system-level pipeline. This can lead to modeling inefficiencies and may introduce inconsistencies that limit the achievable naturalness. We propose to instead synthesize the two modalities in a single model, a new problem we call integrated speech and gesture synthesis (ISG). We also propose a set of models modified from state-of-the-art neural speech-synthesis engines to achieve this goal. We evaluate the models in three carefully-designed user studies, two of which evaluate the synthesized speech and gesture in isolation, plus a combined study that evaluates the models like they will be used in real-world applications - speech and gesture presented together. The results show that participants rate one of the proposed integrated synthesis models as being as good as the state-of-the-art pipeline system we compare against, in all three tests. The model is able to achieve this with faster synthesis time and greatly reduced parameter count compared to the pipeline system, illustrating some of the potential benefits of treating speech and gesture synthesis together as a single, unified problem., Part of proceedings ISBN 9781450384810QC 20220602

Text-to-speech and co-speech gesture synthesis have until now been treated as separate areas by two different research communities, and applications merely stack the two technologies using a simple system-level pipeline. This can lead to modeling inefficiencies and may introduce inconsistencies that limit the achievable naturalness. We propose to instead synthesize the two modalities in a single model, a new problem we call integrated speech and gesture synthesis (ISG). We also propose a set of models modified from state-of-the-art neural speech-synthesis engines to achieve this goal. We evaluate the models in three carefully-designed user studies, two of which evaluate the synthesized speech and gesture in isolation, plus a combined study that evaluates the models like they will be used in real-world applications - speech and gesture presented together. The results show that participants rate one of the proposed integrated synthesis models as being as good as the state-of-the-art pipeline system we compare against, in all three tests. The model is able to achieve this with faster synthesis time and greatly reduced parameter count compared to the pipeline system, illustrating some of the potential benefits of treating speech and gesture synthesis together as a single, unified problem., Part of proceedings ISBN 9781450384810QC 20220602

Text-to-speech and co-speech gesture synthesis have until now been treated as separate areas by two different research communities, and applications merely stack the two technologies using a simple system-level pipeline. This can lead to modeling inefficiencies and may introduce inconsistencies that limit the achievable naturalness. We propose to instead synthesize the two modalities in a single model, a new problem we call integrated speech and gesture synthesis (ISG). We also propose a set of models modified from state-of-the-art neural speech-synthesis engines to achieve this goal. We evaluate the models in three carefully-designed user studies, two of which evaluate the synthesized speech and gesture in isolation, plus a combined study that evaluates the models like they will be used in real-world applications - speech and gesture presented together. The results show that participants rate one of the proposed integrated synthesis models as being as good as the state-of-the-art pipeline system we compare against, in all three tests. The model is able to achieve this with faster synthesis time and greatly reduced parameter count compared to the pipeline system, illustrating some of the potential benefits of treating speech and gesture synthesis together as a single, unified problem., Part of proceedings ISBN 9781450384810QC 20220602

Text-to-speech and co-speech gesture synthesis have until now been treated as separate areas by two different research communities, and applications merely stack the two technologies using a simple system-level pipeline. This can lead to modeling inefficiencies and may introduce inconsistencies that limit the achievable naturalness. We propose to instead synthesize the two modalities in a single model, a new problem we call integrated speech and gesture synthesis (ISG). We also propose a set of models modified from state-of-the-art neural speech-synthesis engines to achieve this goal. We evaluate the models in three carefully-designed user studies, two of which evaluate the synthesized speech and gesture in isolation, plus a combined study that evaluates the models like they will be used in real-world applications - speech and gesture presented together. The results show that participants rate one of the proposed integrated synthesis models as being as good as the state-of-the-art pipeline system we compare against, in all three tests. The model is able to achieve this with faster synthesis time and greatly reduced parameter count compared to the pipeline system, illustrating some of the potential benefits of treating speech and gesture synthesis together as a single, unified problem., Part of proceedings ISBN 9781450384810QC 20220602

Text-to-speech and co-speech gesture synthesis have until now been treated as separate areas by two different research communities, and applications merely stack the two technologies using a simple system-level pipeline. This can lead to modeling inefficiencies and may introduce inconsistencies that limit the achievable naturalness. We propose to instead synthesize the two modalities in a single model, a new problem we call integrated speech and gesture synthesis (ISG). We also propose a set of models modified from state-of-the-art neural speech-synthesis engines to achieve this goal. We evaluate the models in three carefully-designed user studies, two of which evaluate the synthesized speech and gesture in isolation, plus a combined study that evaluates the models like they will be used in real-world applications - speech and gesture presented together. The results show that participants rate one of the proposed integrated synthesis models as being as good as the state-of-the-art pipeline system we compare against, in all three tests. The model is able to achieve this with faster synthesis time and greatly reduced parameter count compared to the pipeline system, illustrating some of the potential benefits of treating speech and gesture synthesis together as a single, unified problem., Part of proceedings ISBN 9781450384810QC 20220602

Ambient noise generated by flowing water turbulence is harnessed as a signal source for imaging key parameters and fault detection in water pipelines. This approach is important because it can aid in the estimation of wave speed or detection of water pipeline defects such as blockages and leakages. More importantly it overcomes the challenging problem of generating a signal source of sufficient power to provide the necessary signal-to-noise ratios for conventional water pipeline imaging and fault detection techniques. In this paper, the expressions of the auto- and cross-correlation functions of the ambient noise between sensors are derived using wave theory. It is shown that the time-domain Green's functions can be extracted from the correlation functions. Experimental and numerical examples are provided for water pipelines to demonstrate that wave speed can be estimated from the time-domain Green's functions. A method for extending the technique, by using straightforward but accurate approximations of the correlation functions, to detect the presence of defects in the profile of the water pipeline is also proposed.

Leak location in water-supply pipelines is of great significance in order to preserve water resources and reduce economic losses. Cross-correlation (CC) based leak location is a popular and effective method in water-supply pipelines (WSP). However, with a decrease of signal to noise ratio (SNR), the errors of time-delay estimation (TDE) based on CC will become larger making it almost impossible to determine a leakage position. Hence, this work proposes leak location based on a combination of phase difference spectrum and variational mode decomposition (PDS-VMD) of leakage-induced vibration signal under low SNR for WSP. Firstly, the leakage-induced vibration signal is decomposed into several intrinsic mode functions (IMFs) by VMD, where the characteristic frequency band is determined by PDS of cross spectrum of two leakage signals. Then, the energy ratio of leakage signal in characteristic frequency band serves as a guideline to select effective IMF components from the decomposed IMFs. Finally, the selective IMFs are reconstituted into a new signal which can be used to determine a leak position using CC based TDE. In order to verify the effectiveness of the proposed leak location algorithm, the method based on PDS-VMD is compared with that using CC, combination of CC coefficient and VMD (CCC-VMD) using both simulation and experiment. The simulation and experimental results demonstrate that the proposed PDS-VMD method is more suitable for leak location in WSP, which provides immunity to both broadband and narrow band noise under low SNR. © 2020 IEEE.

Leak location in water-supply pipelines is of great significance in order to preserve water resources and reduce economic losses. Cross-correlation (CC) based leak location is a popular and effective method in water-supply pipelines (WSP). However, with a decrease of signal to noise ratio (SNR), the errors of time-delay estimation (TDE) based on CC will become larger making it almost impossible to determine a leakage position. Hence, this work proposes leak location based on a combination of phase difference spectrum and variational mode decomposition (PDS-VMD) of leakage-induced vibration signal under low SNR for WSP. Firstly, the leakage-induced vibration signal is decomposed into several intrinsic mode functions (IMFs) by VMD, where the characteristic frequency band is determined by PDS of cross spectrum of two leakage signals. Then, the energy ratio of leakage signal in characteristic frequency band serves as a guideline to select effective IMF components from the decomposed IMFs. Finally, the selective IMFs are reconstituted into a new signal which can be used to determine a leak position using CC based TDE. In order to verify the effectiveness of the proposed leak location algorithm, the method based on PDS-VMD is compared with that using CC, combination of CC coefficient and VMD (CCC-VMD) using both simulation and experiment. The simulation and experimental results demonstrate that the proposed PDS-VMD method is more suitable for leak location in WSP, which provides immunity to both broadband and narrow band noise under low SNR. © 2020 IEEE.

Peroxides are widely used as crosslinkers in polyethylene (PE) drinking water pipes. Cross-linked polyethylene (PEX) has better mechanical properties than PE, but peroxide decomposition by-products can migrate from PEX water pipes into the drinking water unless sufficient preventive actions are undertaken. This work systematically examines the migration of tert-Butyl methyl ether (MTBE), a dominating crosslinking by-product from PEX water pipes, into tap water by utilizing both experimental techniques and finite element (FEM) diffusion modeling. The effects of pipe geometry, tap water temperature (23–80 °C), boundary conditions (air or water interface) and degasing (at 180 °C) were considered. The MTBE diffusivity increased strongly with increasing temperature and it was concluded that a desired water quality can be achieved with proper degasing of the PEX pipes. As the FEM simulations were in excellent agreement with the experimental results, the model can accurately predict the MTBE concentration as a function of time, water temperature and PEX pipe geometry, and enable the pipe manufacturers to aid in ensuring desirable drinking water quality., QC 20190715

Peroxides are widely used as crosslinkers in polyethylene (PE) drinking water pipes. Cross-linked polyethylene (PEX) has better mechanical properties than PE, but peroxide decomposition by-products can migrate from PEX water pipes into the drinking water unless sufficient preventive actions are undertaken. This work systematically examines the migration of tert-Butyl methyl ether (MTBE), a dominating crosslinking by-product from PEX water pipes, into tap water by utilizing both experimental techniques and finite element (FEM) diffusion modeling. The effects of pipe geometry, tap water temperature (23–80 °C), boundary conditions (air or water interface) and degasing (at 180 °C) were considered. The MTBE diffusivity increased strongly with increasing temperature and it was concluded that a desired water quality can be achieved with proper degasing of the PEX pipes. As the FEM simulations were in excellent agreement with the experimental results, the model can accurately predict the MTBE concentration as a function of time, water temperature and PEX pipe geometry, and enable the pipe manufacturers to aid in ensuring desirable drinking water quality., QC 20190715

Extended partial blockages in urban water supply systems (UWSS) are formed from complicated physical, chemical, and biological processes; thus, these blockages are commonly in random and nonuniform geometries. The transient-based blockage detection method (TBBDM) has been evidenced in many applications to be a promising way to diagnose these blockages. Despite the successful validation and application of the TBBDM in the literature, pipe blockages used in these studies were idealized and simplified to regular and uniform shape, which are however not common in practical UWSS, and thus invalidity and inaccuracy of this TBBDM has been widely observed in practical applications. This paper presents fundamental research on understanding the influence of more realistic and nonuniform blockages on transient wave behavior and the accuracy of current TBBDM. The blockage with a linearly varying diameter (termed as nonuniform blockage) is firstly investigated by the frequency domain analytical analysis for its impact on transient wave behavior, which is thereafter incorporated in the overall transfer matrix of transient frequency response for reservoir-pipeline-valve systems. The results indicate the nonuniform blockage may induce very different modification patterns on the frequency shift and amplitude change of transient waves from the uniform blockage situation. © 2018 American Society of Civil Engineers.

Extended partial blockages in urban water supply systems (UWSS) are formed from complicated physical, chemical, and biological processes; thus, these blockages are commonly in random and nonuniform geometries. The transient-based blockage detection method (TBBDM) has been evidenced in many applications to be a promising way to diagnose these blockages. Despite the successful validation and application of the TBBDM in the literature, pipe blockages used in these studies were idealized and simplified to regular and uniform shape, which are however not common in practical UWSS, and thus invalidity and inaccuracy of this TBBDM has been widely observed in practical applications. This paper presents fundamental research on understanding the influence of more realistic and nonuniform blockages on transient wave behavior and the accuracy of current TBBDM. The blockage with a linearly varying diameter (termed as nonuniform blockage) is firstly investigated by the frequency domain analytical analysis for its impact on transient wave behavior, which is thereafter incorporated in the overall transfer matrix of transient frequency response for reservoir-pipeline-valve systems. The results indicate the nonuniform blockage may induce very different modification patterns on the frequency shift and amplitude change of transient waves from the uniform blockage situation. © 2018 American Society of Civil Engineers.

Notorious for its high poverty levels and low socio-economic status, the Navajo Nation’s socio-economic well-being is hindered greatly in part by the lack of an adequate potable water infrastructure which has resulted in health disparities and has attributed to stunted economic growth within the Nation. Large candidate regional water transmission pipelines projects aimed to meet these needs have been identified. With capital costs exceeding their fiscal capability, decision-makers must choose projects that generate the most bang for the buck. To address these challenges, three (3) interconnected planning tools have been developed: (1) a water pipe installation construction cost estimation model (WaterCOSTE) to improve the accuracy of capital cost estimates; (2) a hydraulic optimization model (WaterTRANS) that improves design efficiency for branched water transmission systems; and (3) a decision support system (DSS) that allows candidate water transmission projects to be ranked while considering economic development, health improvement and environmental protection objectives. Estimates derived from WaterCOSTE are used as input into WaterTRANS to find least-cost system designs. The system costs along with other project data are then input into the DSS to determine project rankings. To demonstrate how the DSS can be used and applied, two candidate projects on the Navajo Nation are evaluated. The tools developed will enable decision-makers to improve planning processes and make wiser investment decisions that will lead to expanding the water infrastructure coverage and living conditions on the Navajo Nation.

[EN] This work considers the behaviour of air inside pipes when the air is expelled through air valves. Generally, the air shows isothermal behaviour. Nevertheless, when the transient is very fast, it shows adiabatic behaviour. In a real installation, an intermediate evolution between these two extreme conditions occurs. Thus, it is verified that the results vary significantly depending on the hypothesis adopted. To determine the pressure of the air pocket, the most unfavourable hypothesis (isothermal behaviour) is typically adopted. Nevertheless, from the perspective of the water hammer that takes place when the water column arrives at the air valve and abruptly closes, the most unfavourable hypothesis is the opposite (adiabatic behaviour). In this case, the residual velocity with which the water arrives at the air valve is higher, and, consequently, the water hammer generated is greater.

[EN] This work considers the behaviour of air inside pipes when the air is expelled through air valves. Generally, the air shows isothermal behaviour. Nevertheless, when the transient is very fast, it shows adiabatic behaviour. In a real installation, an intermediate evolution between these two extreme conditions occurs. Thus, it is verified that the results vary significantly depending on the hypothesis adopted. To determine the pressure of the air pocket, the most unfavourable hypothesis (isothermal behaviour) is typically adopted. Nevertheless, from the perspective of the water hammer that takes place when the water column arrives at the air valve and abruptly closes, the most unfavourable hypothesis is the opposite (adiabatic behaviour). In this case, the residual velocity with which the water arrives at the air valve is higher, and, consequently, the water hammer generated is greater.

A Computational Fluid Dynamics (CFD) model was developed to analyze the open-channel flow in a new set of egg-shaped pipes for small combined sewer systems. The egg-shaped cross-section was selected after studying several geometries under different flow conditions. Once the egg-shaped cross-section was defined, a real-scale physical model was built and a series of partial-full flow experiments were performed in order to validate the numerical simulations. Furthermore, the numerical velocity distributions were compared with an experimental formulation for analytic geometries, with comparison results indicating a satisfactory concordance. After the hydraulic performance of the egg-shaped pipe was analyzed, the numerical model was used to compare the average velocity and shear stress against an equivalent area circular pipe under low flow conditions. The proposed egg shape showed a better flow performance up to a filling ratio of h/H = 0.25.

A non-intrusive fault detection technology for real time condition assessment of pipelines is highly desirable for pipeline operators and the use of artificially induced fluid transients for this purpose has been the topic of many studies in the past. Fluid transients are stress waves in the fluid that can propagate through pipelines at high speeds and can collect information on the pipe condition during its travel. Whilst many transient-based fault detection methods have been proposed in the literature, little work was done on the characteristics of the transient signal that is best suited for fault detection. Such a study is critical for the development of this technology as the generation of controlled pressure waves is a challenging key step of the procedure. This paper presents analytical, numerical and experimental results to illustrate the effect of signal bandwidth (frequency content) of the induced transient signals has on the spatial resolution, accuracy and range of transient based fault detection. The results demonstrate that higher bandwidth signals provide more accurate fault detection at the expense of detection range. (C) 2014 American Society of Civil Engineers.

A non-intrusive fault detection technology for real time condition assessment of pipelines is highly desirable for pipeline operators and the use of artificially induced fluid transients for this purpose has been the topic of many studies in the past. Fluid transients are stress waves in the fluid that can propagate through pipelines at high speeds and can collect information on the pipe condition during its travel. Whilst many transient-based fault detection methods have been proposed in the literature, little work was done on the characteristics of the transient signal that is best suited for fault detection. Such a study is critical for the development of this technology as the generation of controlled pressure waves is a challenging key step of the procedure. This paper presents analytical, numerical and experimental results to illustrate the effect of signal bandwidth (frequency content) of the induced transient signals has on the spatial resolution, accuracy and range of transient based fault detection. The results demonstrate that higher bandwidth signals provide more accurate fault detection at the expense of detection range. (C) 2014 American Society of Civil Engineers.

A non-intrusive fault detection technology for real time condition assessment of pipelines is highly desirable for pipeline operators and the use of artificially induced fluid transients for this purpose has been the topic of many studies in the past. Fluid transients are stress waves in the fluid that can propagate through pipelines at high speeds and can collect information on the pipe condition during its travel. Whilst many transient-based fault detection methods have been proposed in the literature, little work was done on the characteristics of the transient signal that is best suited for fault detection. Such a study is critical for the development of this technology as the generation of controlled pressure waves is a challenging key step of the procedure. This paper presents analytical, numerical and experimental results to illustrate the effect of signal bandwidth (frequency content) of the induced transient signals has on the spatial resolution, accuracy and range of transient based fault detection. The results demonstrate that higher bandwidth signals provide more accurate fault detection at the expense of detection range. (C) 2014 American Society of Civil Engineers.

Extended partial blockages are common in pressurized water pipelines and can result in the wastage of energy, the reduction in system carrying capacity and the increased potential for contamination. This paper investigates the transient wave-blockage interaction and its application to extended blockage detection in pipelines, where blockage induced changes to the system resonant frequencies are observed. The frequency shifting is first inspected and explained in this study through wave perturbation analysis, providing a theoretical confirmation for the result that unlike discrete blockages, extended blockages cause resonant frequency shifts in the system. Furthermore, an analytical expression is derived for the relationship between the blockage properties and the resonant frequency shifts and is used to detect the blockages in this study. The obtained results are validated through both numerical applications and laboratory experiments, where the accuracy and efficiency of the developed method for extended blockage detection are tested. (C) 2013 Elsevier Ltd. All rights reserved.

Extended partial blockages are common in pressurized water pipelines and can result in the wastage of energy, the reduction in system carrying capacity and the increased potential for contamination. This paper investigates the transient wave-blockage interaction and its application to extended blockage detection in pipelines, where blockage induced changes to the system resonant frequencies are observed. The frequency shifting is first inspected and explained in this study through wave perturbation analysis, providing a theoretical confirmation for the result that unlike discrete blockages, extended blockages cause resonant frequency shifts in the system. Furthermore, an analytical expression is derived for the relationship between the blockage properties and the resonant frequency shifts and is used to detect the blockages in this study. The obtained results are validated through both numerical applications and laboratory experiments, where the accuracy and efficiency of the developed method for extended blockage detection are tested. (C) 2013 Elsevier Ltd. All rights reserved.

Extended partial blockages are common in pressurized water pipelines and can result in the wastage of energy, the reduction in system carrying capacity and the increased potential for contamination. This paper investigates the transient wave-blockage interaction and its application to extended blockage detection in pipelines, where blockage induced changes to the system resonant frequencies are observed. The frequency shifting is first inspected and explained in this study through wave perturbation analysis, providing a theoretical confirmation for the result that unlike discrete blockages, extended blockages cause resonant frequency shifts in the system. Furthermore, an analytical expression is derived for the relationship between the blockage properties and the resonant frequency shifts and is used to detect the blockages in this study. The obtained results are validated through both numerical applications and laboratory experiments, where the accuracy and efficiency of the developed method for extended blockage detection are tested. (C) 2013 Elsevier Ltd. All rights reserved.

Partial blockages commonly exist in pressurized pipeline systems, and the rapid remediation of such faults is required to reduce the wastage of energy as well as to maintain the serviceability of the pipe network. Numerous transient test-based techniques (TTBT) have been developed for detecting pipe defects, with each technique providing different advantages. Two previously developed techniques-pressure signal analysis (PSA) and frequency response analysis (FRA)-are experimentally tested in this study on systems of different pipe material and characteristics. Each method is validated using the experimental data, and the results show that PSA is most accurate for locating the blockage while FRA is most accurate for determining the radial constriction and length of the blockage section. To take advantage of the different strengths of the techniques, a coupling of the two methods is proposed. Experimental application results reveal that both detection accuracy and calculation efficiency are improved when the coupled method is used instead of the original techniques applied individually. Moreover, the results indicate that current TTBTs for partial blockage detection are more reliable in elastic (metallic) pipelines compared to viscoelastic (plastic) pipes.

This paper investigates the effect that an extended blockage has on a transient signal by examining numerical and experimental results in the time and frequency domains. Extended blockages can develop in pipelines via the processes of tuberculation, scaling, bio film growth, sediment deposition or through designed reductions in pipe diameter. It is identified that consideration of the gradual formation of these faults is important in pipeline design as they can significantly change the fundamental period of a pipelines transient response, maximum and minimum transient pressure heads and the evolution of the transient signal, thus potentially increasing a systems susceptibility to failure. Analysis of transient signals affected by a blockage provides information on the property and location of the extended blockage. In this paper, comparisons between discrete and extended blockage models are made and the effects of changes in blockage diameter, length and wave speed on the transient response are investigated. Furthermore, the ability of existing models to represent extended pipeline faults under transient conditions is evaluated through comparisons of numerical transient responses with new experimental results from the laboratory. Results show that the transient behaviour is modelled with a good level of accuracy over the first few periods of oscillation and that the level of accuracy decays with time. A periodic Fourier analysis of the data demonstrates that the damping rates of the experimental response are higher than the numerical predictions. Applying this new method of signal analysis has shown that the transient signal exhibits larger damping rates in the higher frequency components of the response.

Partial blockages commonly exist in pressurized pipeline systems, and the rapid remediation of such faults is required to reduce the wastage of energy as well as to maintain the serviceability of the pipe network. Numerous transient test-based techniques (TTBT) have been developed for detecting pipe defects, with each technique providing different advantages. Two previously developed techniques-pressure signal analysis (PSA) and frequency response analysis (FRA)-are experimentally tested in this study on systems of different pipe material and characteristics. Each method is validated using the experimental data, and the results show that PSA is most accurate for locating the blockage while FRA is most accurate for determining the radial constriction and length of the blockage section. To take advantage of the different strengths of the techniques, a coupling of the two methods is proposed. Experimental application results reveal that both detection accuracy and calculation efficiency are improved when the coupled method is used instead of the original techniques applied individually. Moreover, the results indicate that current TTBTs for partial blockage detection are more reliable in elastic (metallic) pipelines compared to viscoelastic (plastic) pipes.

This paper investigates the effect that an extended blockage has on a transient signal by examining numerical and experimental results in the time and frequency domains. Extended blockages can develop in pipelines via the processes of tuberculation, scaling, bio film growth, sediment deposition or through designed reductions in pipe diameter. It is identified that consideration of the gradual formation of these faults is important in pipeline design as they can significantly change the fundamental period of a pipelines transient response, maximum and minimum transient pressure heads and the evolution of the transient signal, thus potentially increasing a systems susceptibility to failure. Analysis of transient signals affected by a blockage provides information on the property and location of the extended blockage. In this paper, comparisons between discrete and extended blockage models are made and the effects of changes in blockage diameter, length and wave speed on the transient response are investigated. Furthermore, the ability of existing models to represent extended pipeline faults under transient conditions is evaluated through comparisons of numerical transient responses with new experimental results from the laboratory. Results show that the transient behaviour is modelled with a good level of accuracy over the first few periods of oscillation and that the level of accuracy decays with time. A periodic Fourier analysis of the data demonstrates that the damping rates of the experimental response are higher than the numerical predictions. Applying this new method of signal analysis has shown that the transient signal exhibits larger damping rates in the higher frequency components of the response.

Partial blockages commonly exist in pressurized pipeline systems, and the rapid remediation of such faults is required to reduce the wastage of energy as well as to maintain the serviceability of the pipe network. Numerous transient test-based techniques (TTBT) have been developed for detecting pipe defects, with each technique providing different advantages. Two previously developed techniques-pressure signal analysis (PSA) and frequency response analysis (FRA)-are experimentally tested in this study on systems of different pipe material and characteristics. Each method is validated using the experimental data, and the results show that PSA is most accurate for locating the blockage while FRA is most accurate for determining the radial constriction and length of the blockage section. To take advantage of the different strengths of the techniques, a coupling of the two methods is proposed. Experimental application results reveal that both detection accuracy and calculation efficiency are improved when the coupled method is used instead of the original techniques applied individually. Moreover, the results indicate that current TTBTs for partial blockage detection are more reliable in elastic (metallic) pipelines compared to viscoelastic (plastic) pipes.

This paper investigates the effect that an extended blockage has on a transient signal by examining numerical and experimental results in the time and frequency domains. Extended blockages can develop in pipelines via the processes of tuberculation, scaling, bio film growth, sediment deposition or through designed reductions in pipe diameter. It is identified that consideration of the gradual formation of these faults is important in pipeline design as they can significantly change the fundamental period of a pipelines transient response, maximum and minimum transient pressure heads and the evolution of the transient signal, thus potentially increasing a systems susceptibility to failure. Analysis of transient signals affected by a blockage provides information on the property and location of the extended blockage. In this paper, comparisons between discrete and extended blockage models are made and the effects of changes in blockage diameter, length and wave speed on the transient response are investigated. Furthermore, the ability of existing models to represent extended pipeline faults under transient conditions is evaluated through comparisons of numerical transient responses with new experimental results from the laboratory. Results show that the transient behaviour is modelled with a good level of accuracy over the first few periods of oscillation and that the level of accuracy decays with time. A periodic Fourier analysis of the data demonstrates that the damping rates of the experimental response are higher than the numerical predictions. Applying this new method of signal analysis has shown that the transient signal exhibits larger damping rates in the higher frequency components of the response.

The possibility of leak detection in a viscoelastic pipe system is studied. The frequency response function method (FRFM) is used for leak detection, and the analytical expression for the FRFM originally developed for an elastic pipeline is extended to the viscoelastic situation in this study. The extended FRFM is validated from numerical experiments with one-dimensional viscoelastic transient models. The analysis shows that the pipe-wall viscoelasticity effect has significant impact on the amplitude damping and phase shift of the pressure wave, but little influence on the leak-induced patterns of pressure head peaks in transient system frequency responses. The results indicate that the extended FRFM is applicable to the viscoelastic situation. The impact of viscoelastic parameters and incident wave bandwidth on the applicability of the extended FRFMi also investigated in this paper, and the results imply that transient input signals with rapid changes in time are preferable for leak location in viscoelastic pipelines. DOI: 10.1061/(ASCE)HY.1943-7900.0000495. (C) 2012 American Society of Civil Engineers.

Active research has been going on to validate the Power Law in physics, economics, linguistics, sociology, geophysics etc. This paper sets out to test the hypothesis that the Power Law is a feature of water and wastewater pipeline networks in cities. Databases from 30 different municipalities in Norway serve as the raw data to be processed. The findings may seem a bit intuitive in retrospect, but the numerical results provide some interesting insights. There is greater conformity to the Power Law when the number of pipelines in different lengthclasses is taken into account, as compared to when the total length in each length-class is considered. By considering only the equations with a high degree or conformity to the Power Law, it is possible to derive a standard equation representing an average saturated Norwegian water-wastewater pipeline network. The authors recommend similar analyses of networks in other parts of the world., Investigació activa s'ha estat desenvolupant per validar la Llei de Potències en física, economia, lingüística, sociologia, geofísica, etc. En aquest treball es pretén provar la hipòtesi de que la Llei Potencial és una característica que compleixen les xarxes de canonades d'aigua i aigües residuals a les ciutats. Les bases de dades de 30 municipis noruecs serveixen d'informació primària per ésser processats. Els descobriments podrien ser una mica primitius en retrospectiva, però els resultats numèrics ofereixen algunes idees interessants. Hi ha una major conformitat amb la Llei Potencial quan es té en compte el nombre de canonades en diverses classes de longitud en comparació a quan es considera la longitud total en cada classe de longitud. Al considerar només les equacions un alt grau o conformitat amb la Llei Potencial, és possible derivar una equació estàndard que representi la saturació mitjana de la xarxa noruega de canonades d'aigua i aigües residuals. Els autors recomanen anàlisis similars de xarxes en altres parts del món., Investigación activa se ha estado desarrollando para validar la Ley de Potencias en física, economía, lingüística, sociología, geofísica, etc. En este trabajo se pretende probar la hipótesis de que la Ley Potencial es un rasgo que cumplen las redes de tuberías de agua y aguas residuales en las ciudades. Las bases de datos de 30 municipios noruegos sirven de información primaria para ser procesados. Los hallazgos podrían parecer un poco intuitivos en retrospectiva, pero los resultados numéricos ofrecen algunas ideas interesantes. Hay una mayor conformidad con la Ley Potencial cuando se toma en cuenta el número de tuberías en diferentes clases de longitud, en comparación a cuando se considera la longitud total en cada clase de longitud. Al considerar sólo las ecuaciones con un alto grado o conformidad con la Ley Potencial, es posible derivar una ecuación estándar que represente la saturación promedio de la red noruega de tuberías de agua y aguas residuales. Los autores recomiendan análisis similares de redes en otras partes del mundo., Peer Reviewed

The possibility of leak detection in a viscoelastic pipe system is studied. The frequency response function method (FRFM) is used for leak detection, and the analytical expression for the FRFM originally developed for an elastic pipeline is extended to the viscoelastic situation in this study. The extended FRFM is validated from numerical experiments with one-dimensional viscoelastic transient models. The analysis shows that the pipe-wall viscoelasticity effect has significant impact on the amplitude damping and phase shift of the pressure wave, but little influence on the leak-induced patterns of pressure head peaks in transient system frequency responses. The results indicate that the extended FRFM is applicable to the viscoelastic situation. The impact of viscoelastic parameters and incident wave bandwidth on the applicability of the extended FRFMi also investigated in this paper, and the results imply that transient input signals with rapid changes in time are preferable for leak location in viscoelastic pipelines. DOI: 10.1061/(ASCE)HY.1943-7900.0000495. (C) 2012 American Society of Civil Engineers.

This paper proposes a technique for the detection of extended blockages in pressurized water pipelines by using the system frequency responses under transient conditions. The impact of extended blockages on the system frequency responses is illustrated by using the analytical transfer matrix method, and the results indicate that extended blockages cause the resonant frequencies of the system to shift, and the blockage locations and sizes can be determined by analyzing the occurrences of the resonant peaks in the frequency axis. The analytical derivations of the blockage effect on the resonant frequencies are validated through different numerical experiments, and the applied results demonstrate that the extended blockages in pipeline can be detected by the proposed method as long as the system resonant frequencies are accurately determined. Practical implementations of the findings are discussed at the end of this paper. © 2012 American Society of Civil Engineers.

This paper proposes a technique for the detection of extended blockages in pressurized water pipelines by using the system frequency responses under transient conditions. The impact of extended blockages on the system frequency responses is illustrated by using the analytical transfer matrix method, and the results indicate that extended blockages cause the resonant frequencies of the system to shift, and the blockage locations and sizes can be determined by analyzing the occurrences of the resonant peaks in the frequency axis. The analytical derivations of the blockage effect on the resonant frequencies are validated through different numerical experiments, and the applied results demonstrate that the extended blockages in pipeline can be detected by the proposed method as long as the system resonant frequencies are accurately determined. Practical implementations of the findings are discussed at the end of this paper. © 2012 American Society of Civil Engineers.

Li, S., Xia, C., Cheng, Z., Mao, W., Liu, Y., & Habibi, D. (2020). Leak location based on PDS-VMD of leakage-induced vibration signal under low SNR in water-supply pipelines. IEEE Access, 8, 68091-68102. https://doi.org/10.1109/ACCESS.2020.2984640

This project aimed to implement the advances in new technologies to develop a robotic-based autonomous inspection system for underground pipelines. The new technology is based on the combination of intelligent powerful portable software and the newly advancement in mapping techniques. The system can scan and reconstruct the 3D profile of a pipeline in real-time using a networked system of ground robots. LiDAR (Light Detection and Ranging), Infrared (IR) cameras and 3D cameras with other NDT (Non-Destructive Testing) sensors used to generate the 3D profiles of the pipes as the robots with the advanced sensors autonomously move inside the pipes. During the pipe condition assessment, video files, pictures, and other scans like LiDAR and 3D are used to acquire a lot of data. This becomes cumbersome to interpret and make meaning out of. In the context of human decision-making, we aim at reducing and reordering the data to show to the human inspectors to enhance their decision performance. The proposed method is based on computer vision and pattern recognition algorithms that have proven to improve the proficiency of the inspection process in identifying and locating important features and defects. A complete technology transfer system is developed and proposed to NCDOT for implementation.