Simultaneous Leak Research Articles

Identification Algorithm for Simultaneous Leaks in a Pipeline

This work addresses the problem of simultaneous leaks’ identification in a main pipeline by assuming a constant friction factor. The solution is based on the invariance of the physical leak parameters for any operation point. By considering a quadratic function of the errors between one and two leaks in a pipeline with a steady-state behavior, a new procedure is proposed for the estimation of four parameters associated with the two leaks. In comparison with the algorithm reported in Peralta and Verde (2023), the new one simultaneously adjusts both unknown positions with their gradients. The advantages of the new algorithm are the reduction of maneuvers for obtaining satisfactory estimated parameters and the straightforward estimation of the parameters associated with the orifices through direct nonlinear functions. The results with synthetic data show a considerable improvement regarding the estimation previously reported.

Probability of simultaneous multiple leakages at sections of water networks in the process of localization of hidden water leaks

Hidden leaks from water supply networks account for 50% to 90% of total leakage losses. The presence of two or more simultaneous leaks in a section of the water supply network significantly reduces the accuracy of locating hidden leaks. The method of independent Poisson events and the hypothesis of stationarity, absence of consequences, and ordinariness of leaks are used for the probabilistic description of the problem of multi-leakage in water supply networks. The analytical dependence of the probability of multiple leakages on the specific annual emergency rate of the site, its length and the duration of the localization and repair period is obtained. A generalized semi-empirical equation was obtained for estimating the maximum permissible duration of the localization and repair period depending on the annual emergency rate of the site for a given multi-leakage probability.

Two Simultaneous Leak Diagnosis in Pipelines Based on Input-Output Numerical Differentiation.

This paper addresses the two simultaneous leak diagnosis problem in pipelines based on a state vector reconstruction as a strategy to improve water shortages in large cities by only considering the availability of the flow rate and pressure head measurements at both ends of the pipeline. The proposed algorithm considers the parameters of both leaks as new state variables with constant dynamics, which results in an extended state representation. By applying a suitable persistent input, an invertible mapping in x can be obtained as a function of the input and output, including their time derivatives of the third-order. The state vector can then be reconstructed by means of an algebraic-like observer through the computation of time derivatives using a Numerical Differentiation with Annihilatorsconsidering its inherent noise rejection properties. Experimental results showed that leak parameters were reconstructed with accuracy using a test bed plant built at Cinvestav Guadalajara.

Experimental and Numerical Investigations of Multi-leaks Detection in a Nonhomogenous Pipeline System

This paper focuses on an experimental procedure to localize multiple leaks in a nonhomogenous hydraulic pipeline system made up of three portions of two different materials. Then, an experimental setup originally designed for water hammer study was modified and adapted for leak detection using transients. Two leaks were made in some particular locations in the main pipe and a transient event through a rapid closure of a downstream valve was created. To mimic common practical issues that may be encountered, three main leakage cases were considered; a single leak, two simultaneous leaks and two successive leaks (i.e., one leak that appears followed by an abrupt appearance of a second leak after a period of time). Leaks were experimentally localized by analyzing obtained pressure signals in the excitation point. Results were validated through comparison with numerical ones obtained using the method of characteristics. Additionally, a novel formula to localize the second leak in a successive leaks scenario was presented and its accuracy was confirmed for our test case. Experimental techniques presented in this paper and performed on a test bench at lab scale can be extended and tested on large scale hydraulic pipeline systems.

Intraoperative endoscopy with immediate suture reinforcement of the defect in colorectal anastomosis: a pilot study.

Colorectal anastomosis is the one at higher risk of complication in alimentary tract surgery. Several techniques have been used to intraoperatively check a colorectal anastomosis, without reaching a clear consensus. The aim of the present study is to evaluate the addition of intraoperative flexible endoscopy to indocyanine green fluorescence in detecting colorectal anastomotic defects in a consecutive series of patients. This was a pilot study conducted over a 15-month period. Patients were scheduled for an elective laparoscopic left colectomy or anterior resection with a planned stapled colorectal anastomosis. Pre-, intra- and postoperative data were collected. Intraoperative endoscopy was routinely performed and the anastomotic defects were classified. A suture reinforcement of the defect encountered was immediately performed either laparoscopically or transanally. The primary endpoint of the study was the rate of postoperative complications. Fitfty-two patients were enrolled. At intraoperative endoscopy, 12 anastomotic defects were detected and corrected with immediate suture reinforcement. Defects were classified as two leaks, two mucosal crash, one simultaneous leak and crash, one mucosal edema and six active bleedings. None of these patients developed any postoperative complication. Moreover, there was no postoperative bleeding complication in the entire cohort. The three patients developing a postoperative leak requiring anastomosis takedown were at high risk due to general status and cancer characteristics. Even though more data and a comparative group are needed, the results of this pilot study are very promising regarding the role of intraoperative endoscopy and suture reinforcement of a colorectal anastomotic defect.

Detection of Multiple Leaks in a Natural Gas Pipeline Using Observer and Mixed-Integer Partial Differential Equation-Constrained Optimization

Software-based methods are common approaches for detecting faults in chemical processes. In this paper, new software-based methodologies were developed for locating multiple leaks in a natural gas pipeline. Two types of multiple leaks, subsequent and simultaneous multiple leaks, from a natural gas pipeline were studied, separately. For both subsequent and simultaneous leaks, case studies with two leak occurrences were demonstrated using MATLAB simulation. For detecting and locating subsequent multiple leaks, an unknown input observer was designed and applied, which was modified from our previous study. New optimization methodology for locating simultaneous multiple leaks was demonstrated. Leak locations were estimated by solving a nonlinear global optimization problem. The global optimization problem contained constraints of partial differential equations, integer, and continuous variables. A new discretization approach was proposed and demonstrated, which required significant less computation effect comp...

Leak detection and localization using acoustic emission technique

Article history: Received 6 April, 2015 Accepted 10 October 2015 Available online 11 October 2015 This article provides a method of acoustic emission (AE) technique to detect leakage in pipeline and locate the position of the leakage. The AE sensor is made of piezoelectric effect transducer to pick up the acoustic emission signal which is generated from the turbulent flow at the leak position. The signal conditioning unit is used to enhanced and eliminate the background noise from the leak location sources. The main acoustic emission processing unit is used to acquire and process the extracted AE characteristic parameters from preprocessing waveform. The leak pipeline is simulated by drilling the hole and plugged with M8 screw at different locations. The results show that the proposed AE method can detect and locate simultaneous leak condition in pipeline with promising results. © 2016 Growing Science Ltd. All rights reserved.

Comparative Study of the Leak Characteristics of Two Ceramic/Glass Composite Seals for Solid Oxide Fuel Cells

AbstractSolid oxide fuel cells (SOFCs) have the potential to play a significant role in a future clean energy economy. However, SOFCs still face major obstacles before they can be commercialized, with efficient sealing being among the most prominent. The present research focuses on the comparative study of microstructure, crystal phase evolution, and leak rates, for two ceramic/glass seals used in an SOFC. The leak test apparatus is a controlled facility designed to incorporate different mechanical loading, stack configurations, and thermal cycles. Simultaneous leak testing with an acoustic emission (AE) sensor was also used to identify any micro‐damage in seals. A two‐level factorial design was applied to the first sealing composition to identify the main and the interactive factors for leak rates. MINITAB® was also used to determine a linear regression‐based leak rate model. The second seal formulation employed a more stable glass which led to reduced leak rates. Additional factors in a two‐level factorial design were investigated for the second seal formulation. Based on multiple experiments with different stack components, it was determined that the number of interfaces is most critical for leak rate, showing that even in the presence of thermal cycling, leakage is an interfacial dominated phenomenon.

120 MESENCHYMAL STEM CELL (MSC) SECRETED FACTORS FACILITATE PUDENDAL NERVE (PN) RECOVERY AFTER SIMULATED CHILDBIRTH INJURY

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Basic Research II1 Apr 2012120 MESENCHYMAL STEM CELL (MSC) SECRETED FACTORS FACILITATE PUDENDAL NERVE (PN) RECOVERY AFTER SIMULATED CHILDBIRTH INJURY Charuspong Dissaranan, Emily Holthaus, Michelle Cruz, Brian Balog, Matthew Kiedrowski, Marc Penn, Howard Goldman, and Margot Damaser Charuspong DissarananCharuspong Dissaranan Cleveland, OH More articles by this author , Emily HolthausEmily Holthaus Cleveland, OH More articles by this author , Michelle CruzMichelle Cruz Cleveland, OH More articles by this author , Brian BalogBrian Balog Cleveland, OH More articles by this author , Matthew KiedrowskiMatthew Kiedrowski Akron, OH More articles by this author , Marc PennMarc Penn Akron, OH More articles by this author , Howard GoldmanHoward Goldman Cleveland, OH More articles by this author , and Margot DamaserMargot Damaser Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.168AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES During vaginal delivery the external urethral sphincter (EUS) and its innervation, the PN, can be injured, resulting in stress urinary incontinence. Even 5 years after injury recovery is poor. Previous studies have demonstrated that bone marrow-derived stem cells improve growth and myelination of regenerating axons which may be due to the release of trophic factors. This study investigates if intravenously (IV) injected MSC home to the PN and the EUS and facilitate functional recovery via secretion of paracrine factors after PN crush (PNC). METHODS Age-matched virgin female rats were utilized in 3 experiments: 1. The functional study utilizing MSC had 3 groups: PNC receiving IV phosphate buffered saline (PBS; N=6); PNC receiving 2 million GFP-labeled MSC IV (N=6); and sham PNC receiving IV PBS (N=6). 2. The functional study utilizing media that had been conditioned by MSC and then concentrated (CCM) had 3 groups: PNC receiving CCM by local injection to the crush site of the PN (N=6); PNC receiving local control media injection (N=6); and sham PNC receiving local control media injection (N=6). 3. The homing study had 2 groups: PNC receiving IV MSC (N=11) and sham PNC receiving IV MSC (N=11). All treatments were delivered 1 hour after injury. Urethral function was tested 10 days after injury by simultaneous leak point pressure (LPP) and EUS electromyography (EMG). Mean frequency and amplitude of EUS EMG both at rest and during LPP were calculated. The PN, urethra, vagina, rectum and spleen were harvested and imaged ex-vivo for GFP 2 and 4 days after injection in the homing study. RESULTS LPP was significantly reduced in rats with PNC treated with PBS or control media compared to sham PNC but not in those given IV MSCs or CCM. Similarly, EUS EMG frequency and amplitude were significantly decreased in rats with PNC treated with PBS or control media compared to sham PNC but not in PNC rats treated with IV MSC or CCM. Ex vivo imaging showed significantly increased fluorescence, indicating more MSCs, in the PN and spleen of PNC rats receiving IV MSC. CONCLUSIONS IV infused MSC home to the PN and spleen and facilitate recovery of the PN and continence after simulated childbirth injury. CCM injection locally gave similar results. The mechanism of action leading to restored continence is potentially via secreted paracrine factors. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e48-e49 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Charuspong Dissaranan Cleveland, OH More articles by this author Emily Holthaus Cleveland, OH More articles by this author Michelle Cruz Cleveland, OH More articles by this author Brian Balog Cleveland, OH More articles by this author Matthew Kiedrowski Akron, OH More articles by this author Marc Penn Akron, OH More articles by this author Howard Goldman Cleveland, OH More articles by this author Margot Damaser Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

176 INTRAVENOUS MESENCHYMAL STEM CELLS HOME TO THE URETHRA AND FACILITATE RECOVERY FROM STRESS URINARY INCONTINENCE AFTER CHILDBIRTH INJURY VIA LOCAL SECRETION OF PARACRINE FACTORS

You have accessJournal of UrologyStem Cell Research1 Apr 2011176 INTRAVENOUS MESENCHYMAL STEM CELLS HOME TO THE URETHRA AND FACILITATE RECOVERY FROM STRESS URINARY INCONTINENCE AFTER CHILDBIRTH INJURY VIA LOCAL SECRETION OF PARACRINE FACTORS Charuspong Dissaranan, Michelle Cruz, Bradley Gill, Levilester Salcedo, Anne Cotleur, Raul Mendieta, Brian Balog, Matt Kiedrowski, Marc Penn, Howard Goldman, and Margot Damaser Charuspong DissarananCharuspong Dissaranan Cleveland, OH More articles by this author , Michelle CruzMichelle Cruz Cleveland, OH More articles by this author , Bradley GillBradley Gill Cleveland, OH More articles by this author , Levilester SalcedoLevilester Salcedo Cleveland, OH More articles by this author , Anne CotleurAnne Cotleur Cleveland, OH More articles by this author , Raul MendietaRaul Mendieta Cleveland, OH More articles by this author , Brian BalogBrian Balog Cleveland, OH More articles by this author , Matt KiedrowskiMatt Kiedrowski Cleveland, OH More articles by this author , Marc PennMarc Penn Cleveland, OH More articles by this author , Howard GoldmanHoward Goldman Cleveland, OH More articles by this author , and Margot DamaserMargot Damaser Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.245AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Vaginal delivery injures the nerves, muscle, and connective tissues responsible for maintaining continence and is a risk factor for the development of Stress Urinary Incontinence (SUI). We have previously demonstrated that stem cell homing cytokine MCP-3, and its receptors, are upregulated in urethral tissue after childbirth injury. Recent studies suggest stem cells may facilitate repair by secreting proteins that have paracrine effects. This study investigated whether stem cells homed to the urethra after childbirth injury and facilitated functional recovery of the urethral sphincter. Specifically, the aim of this study was to determine if intravenous (IV) bone marrow-derived mesenchymal stem cells (MSCs) improved urethral sphincter function compared to local administration of concentrated conditioned media (CCM) containing growth factors produced by the cells. METHODS Age-matched virgin female rats were divided into 6 groups: Vaginal Distension (VD) and IV saline (N=6), VD and IV MSCs (N=7), sham VD and IV saline (N=5), VD and CCM direct sphincter injection (N=5), VD and control media injection (N=4) and sham VD and control media injection (N=5). VD was done as previously described. One hour after injury, 2 million GFP-labeled MSCs or saline was injected via tail vein. MSC conditioned media was concentrated (CCM) and injected directly into the urethra. Outcomes were tested 1 week after injury by simultaneous leak point pressure (LPP) and external urethral sphincter (EUS) electromyography (EMG). Mean frequency and amplitude of 1 sec EUS EMG segments both at rest and during LPP were analyzed. Urethras and vaginas were harvested and imaged ex-vivo for MSCs GFP. RESULTS Continence (LPP) was significantly reduced in VD rats treated with saline or control media compared to sham VD but not in those given IV MSCs or CCM. EUS EMG frequency and amplitude, as well as LPP were significantly decreased in all VD rats, regardless of treatment, compared to sham VD. GFP imaging showed increased fluorescence, indicating MSCs, in the urethra and vagina of VD rats receiving IV MSCs. CONCLUSIONS IV MSCs home to the urethra and facilitate recovery of continence after childbirth injury, but not by increasing EUS function. Therefore, improved LPP likely results from the local secretion of paracrine factors by MSCs. The exact mechanism of action leading to restored continence requires further investigation. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetailsCited byGill B, Damaser M, Vasavada S and Goldman H (2018) Stress Incontinence in the Era of Regenerative Medicine: Reviewing the Importance of the Pudendal NerveJournal of Urology, VOL. 190, NO. 1, (22-28), Online publication date: 1-Jul-2013. Volume 185Issue 4SApril 2011Page: e73 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Charuspong Dissaranan Cleveland, OH More articles by this author Michelle Cruz Cleveland, OH More articles by this author Bradley Gill Cleveland, OH More articles by this author Levilester Salcedo Cleveland, OH More articles by this author Anne Cotleur Cleveland, OH More articles by this author Raul Mendieta Cleveland, OH More articles by this author Brian Balog Cleveland, OH More articles by this author Matt Kiedrowski Cleveland, OH More articles by this author Marc Penn Cleveland, OH More articles by this author Howard Goldman Cleveland, OH More articles by this author Margot Damaser Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Grading of Severity of the Condition in Burn Patients by Serum Protein and Albumin/Globulin Studies

Capillary permeability increases after inflammation with consequent leak of fluid, electrolytes, and proteins. The albumin molecule size being smaller (69 kDa) than the globulin molecule (90-156 kDa) will leak relatively at an early stage of the disease (with moderate increase in capillary pore size) than globulin leading to albumin/globulin reversal. In cases with severe permeability changes with rapid progression to larger pore size with simultaneous leak of both albumin and globulin, albumin/globulin reversal will not occur. In this study estimation the serum protein and albumin/globulin (A/G) ratio at frequent intervals was done to grade the severity of the condition of burn patients by assessing the severity of capillary leak.A total of 61 admitted patients (from March 2002 to December 2004) based on the protein values were divided into 3 groups (group 1: 6-8 g/dL, group 2: 5.1-5.9 g/dL, group 3: < or =5.0 g/dL), and all the patients who showed change in their protein levels during the study were shifted to appropriate group and were classified as group shifters. The mean survival time and mortality of various groups were compared, and A/G ratio of all the expired cases was analyzed.Group 3 patients showed higher mortality (95%) as compared to that in other groups (group 1 and 2: 0% each and group shifters: 30.2%). Median survival time of group 3 was significantly low as compared to that of group 1 (P < 0.0026), group 2 (P < 0.0006), and group shifters (P < 0.0000). In group shifters the mean time (days) required for shifting from one group to other just before death or discharge in survivors was significantly higher than that in expired cases. Of 26 cases expired during the study, initial A/G ratio at the time of first assigning the group was not reversed in 22 cases (84.6%).The study concluded that the severity (indicated by lower serum protein values) and speed (judged by A/G ratio changes and median survival time analysis) of capillary permeability changes were associated with high mortality, and therefore, it is possible to grade the severity of the condition in burn patients.

Accommodation of Multi-Leak Positions in a Pipeline

A novel approach is presented for simultaneous leaks detection and location of their positions in a pipeline via the use of updating residual generators. To overcome the isolability problem for two leaks when a simple nonlinear model with only two flow sensors are used, the approach assumes a fluid model discretized in three sections in which their divisions depend on the unknown leaks positions z1 and z2, and can be only identified when the leaks are present. The key of the location scheme is the accommodation of the positions z1 and z2 from a value set which satisfies physical constrains and at the same time minimizes an error signal with respect to (z1, z2). Simulation examples with one and two leaks are given to show the effectiveness of the multi-leak supervision methodology