scholarly journals Leak detection in virtually isolated pipe sections within a complex pipe system using a two-source-four-sensor transient testing configuration

2020 ◽  
Vol 22 (5) ◽  
pp. 1306-1320
Author(s):  
He Shi ◽  
Jinzhe Gong ◽  
Angus R. Simpson ◽  
Aaron C. Zecchin ◽  
Martin F. Lambert
Keyword(s):  
Transfer Matrix ◽  
Leak Detection ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Pipe System ◽  
Pipe Section ◽  
Supply Pipe ◽  
The Difference ◽  
A New Technique ◽  
Single Pipe

Abstract Leak detection in complex pipeline systems is challenging due to complex wave reflections. This research proposes a new technique for leak detection in targeted pipe sections within complex water supply pipe systems using controlled hydraulic transient pressure waves. To ‘virtually isolate’ a targeted pipe section for independent analysis, a two-source-four-sensor transient testing configuration is used to extract the transfer matrix of the targeted pipe section, and it is independent of the system boundary conditions. The imaginary part of the difference between two elements in the transfer matrix is sensitive to leaks. The result should be zero if no leak is present, while a leak will introduce a sinusoidal pattern. An algorithm is developed to extract the leak information, which is applicable to multiple leaks. Two numerical case studies are conducted to validate the new leak detection technique. Case 1 is on a single pipe system with two leaks and deteriorated pipe sections, and pulse pressure waves are used as the excitation. Case 2 is on a simple pipe network with one leak, and pseudo-random binary signals are used as the excitation. The successful determination of the leak location and impedance validates the concept.

scholarly journals A Nelder–Mead algorithm-based inverse transient analysis for leak detection and sizing in a single pipe

2021 ◽  
Author(s):  
Oussama Choura ◽  
Caterina Capponi ◽  
Silvia Meniconi ◽  
Sami Elaoud ◽  
Bruno Brunone
Keyword(s):  
Transient Analysis ◽  
Experimental Tests ◽  
Leak Detection ◽  
Calibration Procedure ◽  
Second Phase ◽  
Viscoelastic Parameters ◽  
The Difference ◽  
Single Pipe ◽  
The University ◽  
Nelder Mead Algorithm

Abstract In this paper the results of an experimental validation of a technique for leak detection in polymeric pipes based on the inverse transient analysis (ITA) are presented. In the proposed ITA the Nelder–Mead algorithm is used as a calibration tool. Experimental tests have been carried out in an intact and leaky high-density polyethylene (HDPE) single pipe installed at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy. Transients have been generated by the fast and complete closure of a valve placed at the downstream end section of the pipe. In the first phase of the calibration procedure, the proposed algorithm has been used to estimate both the viscoelastic parameters of a generalized Kelvin–Voigt model and the unsteady-state friction coefficient, by minimizing the difference between the numerical and experimental results. In the second phase of the procedure, the calibrated model allowed the evaluation of leak size and location with an acceptable accuracy. Precisely, in terms of leak location the relative error was smaller than 5%.

scholarly journals Leak detection by inverse transient analysis in an experimental PVC pipe system

2010 ◽  
Vol 13 (2) ◽  
pp. 153-166 ◽  
Author(s):  
Alexandre Kepler Soares ◽  
Dídia I. C. Covas ◽  
Luisa Fernanda R. Reis
Keyword(s):  
Transient Analysis ◽  
Mechanical Response ◽  
Research Work ◽  
Leak Detection ◽  
Distribution Networks ◽  
Economic Losses ◽  
Water Supply Systems ◽  
Transient Pressure ◽  
Pipe System ◽  
Hydraulic Transient

Leakage reduction in water supply systems and distribution networks has been an increasingly important issue in the water industry since leaks and ruptures result in major physical and economic losses. Hydraulic transient solvers can be used in the system operational diagnosis, namely for leak detection purposes, due to their capability to describe the dynamic behaviour of the systems and to provide substantial amounts of data. In this research work, the association of hydraulic transient analysis with an optimisation model, through inverse transient analysis (ITA), has been used for leak detection and its location in an experimental facility containing PVC pipes. Observed transient pressure data have been used for testing ITA. A key factor for the success of the leak detection technique used is the accurate calibration of the transient solver, namely adequate boundary conditions and the description of energy dissipation effects since PVC pipes are characterised by a viscoelastic mechanical response. Results have shown that leaks were located with an accuracy between 4–15% of the total length of the pipeline, depending on the discretisation of the system model.

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

scholarly journals Annual Spread Rate of Tomentosus Root Disease

Plant Disease ◽  
1997 ◽  
Vol 81 (9) ◽  
pp. 1053-1056 ◽  
Author(s):  
R. S. Hunt ◽  
F. G. Peet
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Root Disease ◽  
Uninfected Control ◽  
Radial Increment ◽  
Spread Rate ◽  
Annual Increment ◽  
Temporal Differences ◽  
The Difference ◽  
A New Technique

The spread rate of tomentosus root disease, caused by Inonotus tomentosus, was investigated by a new technique employing temporal differences in the initiation of the reduced annual radial increment between pairs of diseased trees. Pairs of infected trees (stumps) located on the periphery of disease centers were selected in each of six widely separated spruce (Picea spp.) stands in British Columbia. Distances between 12 pairs of stumps were measured, and disks were collected from each stump. Similarly, disks from four additional pairs were collected from trees in a younger stand. Uninfected control disks were collected for all sites. Tree-ring measurements were determined for all disk samples and the year in which the reduction of the annual increment attributable to I. tomentosus began was determined for infected trees. The difference between initiation years for pairs of infected trees divided into the distance between them produced an average annual spread rate of 20 cm/yr. This rate will be used in developing a model for the disease.

scholarly journals Functional and aesthetic outcomes of spreader graft and auto-spreader flap after nasal hump removal

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Maged Baher Naguib ◽  
Mohamed Rifaat Ahmed ◽  
Yasser Taha Madian ◽  
Tarek Mohamady Elnahriry ◽  
Wael Elshahat Eldeeb
Keyword(s):  
Nasal Obstruction ◽  
Operative Time ◽  
Nasal Valve ◽  
Spreader Graft ◽  
Spreader Flap ◽  
The Mean ◽  
The Difference ◽  
A New Technique ◽  
Nasal Valve Collapse ◽  
Duration Of Operation

Abstract Background Following the reduction of the nasal hump to a desired level, spreader grafts are usually positioned to prevent the complication of nasal valve collapse. Auto-spreader flap is a new technique that gained more popularity recently and can be used as an alternative to spreader graft. This RCCT compared between both techniques aesthetically and functionally as well as the operative time. Results Forty patients, 17 males (42.5%) and 23 females (57.5%), were included. The mean duration of operation in auto-spreader flap was 11.8 ± 3.4 min, while it was 19.2 ± 3.2 min in spreader graft. The difference between the two procedures was statistically significant (P < 0.05). Functional assessment of nasal obstruction was done for all patients in both groups preoperative that was (75.6 ± 19.9) which showed marked improvement when re-evaluated 3 moths postoperatively (18.9 ± 14.7), and after 6 months NOSE scale was (29.1 ± 20.2). The overall aesthetic satisfaction was 62.5% (25 of 40) irrespective of the surgery done. Sixteen out of 20 patients in spreader group and 9 out of 20 in auto-spreader flap group. Conclusion Auto-spreader flap and spreader graft are very effective surgical procedure for treatment of nasal obstruction due to internal nasal valve dysfunction, but the auto-spreader flap had shorter operative time. However, spreader graft has a superior aesthetic outcome.

ACCURATE ANALYSIS OF GLOBAL INTERCONNECTS IN NANO-FPGAs

NANO ◽  
2009 ◽  
Vol 04 (03) ◽  
pp. 171-176 ◽  
Author(s):  
DAVOOD FATHI ◽  
BEHJAT FOROUZANDEH
Keyword(s):  
Propagation Delay ◽  
Modeling Method ◽  
Accurate Analysis ◽  
Proposed Model ◽  
Simulation Results ◽  
The Difference ◽  
A New Technique ◽  
Global Interconnects ◽  
Technology Nodes ◽  
Model Technique

This paper introduces a new technique for analyzing the behavior of global interconnects in FPGAs, for nanoscale technologies. Using this new enhanced modeling method, new enhanced accurate expressions for calculating the propagation delay of global interconnects in nano-FPGAs have been derived. In order to verify the proposed model, we have performed the delay simulations in 45 nm, 65 nm, 90 nm, and 130 nm technology nodes, with our modeling method and the conventional Pi-model technique. Then, the results obtained from these two methods have been compared with HSPICE simulation results. The obtained results show a better match in the propagation delay computations for global interconnects between our proposed model and HSPICE simulations, with respect to the conventional techniques such as Pi-model. According to the obtained results, the difference between our model and HSPICE simulations in the mentioned technology nodes is (0.29–22.92)%, whereas this difference is (11.13–38.29)% for another model.

scholarly journals METHODOLOGY OF THE PRIMARY DATA RECONSTRUCTION OF SINGLE PIPE HEATING SYSTEMS/VIENVAMZDŽIŲ ŠILDYMO SISTEMŲ PIRMINIŲ DUOMENŲ NUSTATYMO METODIKA

1999 ◽  
Vol 5 (5) ◽  
pp. 318-322
Author(s):  
Edvardas Tuomas ◽  
Saulius Neverbickas
Keyword(s):  
World War Ii ◽  
District Heating ◽  
Heating System ◽  
Heat Fluxes ◽  
Primary Data ◽  
Complex Coefficient ◽  
Heating Systems ◽  
Pipe System ◽  
Central Heating ◽  
Single Pipe

The majority of dwellings in Lithuania are situated in blocks of flats. The dwellings were built after World War II and they are heated by single pipe central heating systems, connected to district heating. The dwellers are not quite satisfied with such a heating system and try to improve it, but do that in a wrong way, by increasing the surface of radiators. Such means lead to violation of thermal regime and comfort conditions for other dwellers. There exists sometimes the necessity of reconstructing premises and together—the heating system. During the reconstruction the primary heat fluxes from radiators should be known, but very often such data are lost and only the size of radiators (number of sections) are known. To reconstruct the required primary data for single pipe systems is complicated because the temperatures of inlet and outlet water for radiators are unknown. In this article the methodology is proposed how to perform the calculations leading to the required data. The aim of calculations is the establishment of heat fluxes from each radiator connected to the riser. Heat flux from radiator can be calculated according the formula (1) but the complex coefficient is unknown. It could be found from formulae (2) but some magnitudes are unknown. According to the proposed methodology the values of unknown magnitudes are taken approximately and calculations are performed with iterations. In such a way the flow rate of water in riser is established from formula (3), which is the same for each radiator (the property of single pipe system). From formulas (3) and (4) an equation is produced (5), and is used for calculations of unknown temperatures. The equation (6) is used for calculation of heat fluxes from radiators. To carry out the above-mentioned calculations without computer practically is impossible due to many cycles of iteration. The programme was prepared to make easy all these calculations. The scheme of algorithm of programme is given in Fig 1. An example of calculation is given in this article. Calculations were fulfilled by newly created programme. The riser chosen for calculation is shown in Fig 2. The results of calculation are given in Table 1. The table shows that according to the proposed methodology the programme based on it can be used for reconstruction of primary data of single pipe heating systems successfully.

scholarly journals TWO-POND FEEDING NURSERY FISH BREEDING COMPLEX

2020 ◽  
Author(s):  
Vl. N. Shkura ◽  
◽  
A. V. Shevchenko ◽  
Keyword(s):  
Water Supply ◽  
Water Discharge ◽  
Water Levels ◽  
Design Solution ◽  
Fish Ponds ◽  
Pipe System ◽  
Fish Trap ◽  
Fish Breeding ◽  
The Difference ◽  
Search Design

Purpose: development and description of the layout and design solution for a two-pond feeding nursery fish-breeding complex, which characterizes by compact placement of its constituent structures and their adaptation to the topographic conditions of the territory. Materials and methods. The theoretical and empirical basis for the development was made up of well-known recommendations on design and construction of pond complexes and survey data of operating fish-breeding facilities and their structures. During the development, the technologies of search design of engineering projects in compliance with fish breeding requirements and restrictions were used. Results. The fish-breeding complex includes: two fish-breeding ponds with a common dividing dam and a water supply system including a pumping station; water supply pipe system; a system of devices and structures that ensure the release of fish grown in ponds into a fish trap; spillway devices for discharging water from ponds and a fish trap with a set of regulating elements. Fish ponds are located on the floodplain lands of the river Don and are formed by protecting dikes. The bed of the reservoirs is planned with sections with longitudinal and transverse slopes to the water-fish collecting and-transporting ditches arranged in their bottom, allowing them to be emptied and the fish grown in the ponds to be directed to the outlet structures. The release of fish from the ponds is carried out by two tower water outlets. The design of the fish trap provides for the accumulation and seine fishing, it is equipped with means for regulating water discharge and maintaining conditions for fish. Conclusions. The developed layout and design solution for a two-pond fish-breeding complex with one fish trap is adapted to the local relief and the difference in water levels in ponds and in water intake. The implemented layout and design solutions can be used in the development of similar objects

Leak Detection in Water-Distribution Pipe System

2018 ◽  
Author(s):  
G Dvajasvie ◽  
Banu PK Farisha ◽  
Sachin N Babu ◽  
K P Saheen ◽  
Nikhil C Binoy
Keyword(s):  
Water Distribution ◽  
Leak Detection ◽  
Pipe System
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