期刊文献+
共找到1,706篇文章
< 1 2 86 >
每页显示 20 50 100
Application of an Improved ISODATA Method to Pipeline Leak Detection 被引量:4
1
作者 Hu Jinqiu Zhang Laibin Wang Zhaohui Liang Wei 《Petroleum Science》 SCIE CAS CSCD 2007年第2期97-104,共8页
Increasingly serious leak problem in pipeline transportation has not only affected the operation of pipelines but also caused loss of precious resource and environmental damage. Based on the analysis of the occurrence... Increasingly serious leak problem in pipeline transportation has not only affected the operation of pipelines but also caused loss of precious resource and environmental damage. Based on the analysis of the occurrence of negative pressure waves and the unsupervised learning of pattern recognition, the Interactive Self-organizing Data Analysis Technique Algorithm (ISODATA) method was used to classify the negative pressure waves and then the states of pipelines could be determined. K L transformation was used to eliminate the correlativity of feature parameters and to reduce the dimensionality of feature vector space to speed up calculation. Experimental results validated the accuracy and practical value of this method. 展开更多
关键词 Negative pressure wave ISODATA leak detection K_L transformation
下载PDF
Quantitative risk assessment & leak detection criteria for a subsea oil export pipeline
2
作者 张方元 白勇 +1 位作者 Mohd Fauzi BADARUDDIN Suhartodjo TUTY 《Journal of Marine Science and Application》 2009年第2期168-174,共7页
A quantitative risk assessment (QRA) based on leak detection criteria (LDC) for the design of a proposed subsea oil export pipeline is presented in this paper. The objective of this QRA/LDC study was to determine ... A quantitative risk assessment (QRA) based on leak detection criteria (LDC) for the design of a proposed subsea oil export pipeline is presented in this paper. The objective of this QRA/LDC study was to determine if current leak detection methodologies were sufficient, based on QRA results, while excluding the use of statistical leak detection; if not, an appropriate LDC for the leak detection system would need to be established. The famous UK PARLOC database was used for the calculation of pipeline failure rates, and the software POSVCM from MMS was used for oil spill simulations. QRA results revealed that the installation of a statistically based leak detection system (LDS) can significantly reduce time to leak detection, thereby mitigating the consequences of leakage. A sound LDC has been defined based on QRA study results and comments from various LDS vendors to assist the emergency response team (ERT) to quickly identify and locate leakage and employ the most effective measures to contain damage. 展开更多
关键词 QRA (quantitative risk assessment) RISK LDC leak detection criteria) PARLOC database PIPELINE
下载PDF
Leak Detection of Gas Pipelines Based on Characteristics of Acoustic Leakage and Interfering Signals 被引量:2
3
作者 Lingya Meng Cuiwei Liu +2 位作者 Liping Fang Yuxing Li Juntao Fu 《Sound & Vibration》 2019年第4期111-128,共18页
When acoustic method is used in leak detection for natural gas pipelines,the external interferences including operation of compressor and valve,pipeline knocking,etc.,should be distinguished with acoustic leakage sign... When acoustic method is used in leak detection for natural gas pipelines,the external interferences including operation of compressor and valve,pipeline knocking,etc.,should be distinguished with acoustic leakage signals to improve the accuracy and reduce false alarms.In this paper,the technologies of extracting characteristics of acoustic signals were summarized.The acoustic leakage signals and interfering signals were measured by experiments and the characteristics of time-domain,frequency-domain and time-frequency domain were extracted.The main characteristics of time-domain are mean value,root mean square value,kurtosis,skewness and correlation function,etc.The features in frequency domain were obtained by frequency spectrum analysis and power spectrum density,while time-frequency analysis was accomplished by short time Fourier transform.The results show that the external interferences can be removed effectively by the characteristics of time domain,frequency domain and time-frequency domain.It can be drawn that the acoustic leak detection method can be applied to natural gas pipelines and the characteristics can help reduce false alarms and missing alarms. 展开更多
关键词 leak detection acoustic method signal processing external interference characteristic extraction
下载PDF
Pipeline Potential Leak Detection Technologies: Assessment and Perspective in the Nigeria Niger Delta Region 被引量:2
4
作者 Jasper Agbakwuru 《Journal of Environmental Protection》 2011年第8期1055-1061,共7页
This paper examines the advances in pipeline third party encroachment alert systems and leak control methods in the oil/gas industry. It also highlights the extent of spill/pollution issues in the Niger Delta region d... This paper examines the advances in pipeline third party encroachment alert systems and leak control methods in the oil/gas industry. It also highlights the extent of spill/pollution issues in the Niger Delta region due to intended/unin- tended damages and suggests a possible method of control. It is believed that the best option to avoid pollution due to pipeline failure is to ensure that hydrocarbon does not exit from the pipeline. With the different methods considered in this review, acoustic monitoring of change in the operational sound generated from a given pipeline section is suggested to be practicable to identifying sound abnormalities of third party encroachments. One established challenge of the acoustic system for buried pipelines protection is attenuation of acoustic transmission. An attempt to check the performance of an acoustic transmission on steel pipelines submerged in water points to a similar research on plastic water pipelines that attenuation is small compared with pipe buried in soil. Fortunately, Niger Delta of Nigeria is made of wetland, swamps and shallow water and could therefore offer an opportunity to deploy acoustic system for the safety of pipelines against third party attacks in this region. However, the numerous configuration and quantity of oil installation in this region imply that cost of application will be enormous. It is therefore suggested that a combination of impressed alternating cycle current (IACC) which traces encroachment on the pipeline coating and an acoustic system be used to manage intended and unintended pipeline potential damages. The IACC should be used for flow lines and other short distance delivery lines within the oilfield, while the relatively large diameter and long length delivery, trunk and transmission lines should be considered for acoustic protection. It is, however, noted that further efforts are required to reduce cost and improve effectiveness of these systems. 展开更多
关键词 PIPELINE leakS detection NIGER Delta OIL SPILL OIL Pollution
下载PDF
Leak Detection in Offshore Pipelines of Conveying Fluid 被引量:1
5
作者 李俊花 崔莉 《海洋工程:英文版》 EI 2004年第2期327-333,共7页
Leakage from pipelines has caused serious environmental pollution and economic losses. Usually, leak detection can reduce the damage. The paper mainly discusses a hydraulic gradient-based leak detection method. The ba... Leakage from pipelines has caused serious environmental pollution and economic losses. Usually, leak detection can reduce the damage. The paper mainly discusses a hydraulic gradient-based leak detection method. The basic idea is outlined first, followed by a description of a laboratory experiment in a water pipeline. Several pressure curves are established based on different leak locations under the condition of a constant total flow rate. It is demonstrated that the leak of a large leak quantity can be detected reliably by the hydraulic gradient method. 展开更多
关键词 PIPE leak detection
下载PDF
Leak Detection in Water Distribution Systems Using Bayesian Theory and Fisher’s Law 被引量:1
6
作者 张宏伟 王丽娟 《Transactions of Tianjin University》 EI CAS 2011年第3期181-186,共6页
A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of para... A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of parameter values was quantified by probability density function and updated by Bayesian theory. Values of the parameters were estimated based on Fisher’s law. The amount of leaks was estimated by back propagation neural network. Based on flow characteristics in water distribution systems, the location of leaks can be estimated. The effectiveness of the proposed method was illustrated by simulated leak data of node pressure head and flow rate of pipelines in a test pipe network, and the leaks were spotted accurately and renovated on time. 展开更多
关键词 water distribution systems leak detection EPANET Fisher's law Bayesian theory back propagationneural network
下载PDF
Performing Reliable Early Leak Detection on Storage Tank Terminals:Retrofitting of Existing Facilities and New Buildings
7
作者 Raul Risi 《材料科学与工程(中英文B版)》 2018年第5期188-194,共7页
Liquid leak detection may represent a challenge for Oil&Gas operators,as indicated by operational feed-back and independent studies.Despite the availability of many different leak detection technologies,some syste... Liquid leak detection may represent a challenge for Oil&Gas operators,as indicated by operational feed-back and independent studies.Despite the availability of many different leak detection technologies,some systems may either fail to detect spills or generate frequent false alarms.In particular,possible soil contamination from pre-existing leaks and pollution carry-over by rain water is difficult to filter out by a leak sensing system.Typical case of false alarms relates to punctual sensors installed upstream the drain valve within the storage tank bunds,monitoring possible presence of leaks in rain water.Besides old soil contamination,other criteria should also be considered when selecting a spill detection technology,such as asset type to be monitored(storage tank,pipeline,…),system accuracy(minimum detectable quantity,ability to localize the leak),detection time,reliability over time,capital,installation and operating costs.The paper will include an evaluation of different external leak detection technologies with respect to the above-mentioned criteria,pointing out the capabilities and limitations of each system.Focus will be placed on reliability of leak monitoring systems in challenging environments.A new generation of digital,reusable sensing cables and probes,as well as the impact of sensitivity for different applications,will be discussed.Since leak sensor installation environment(positioning,adoption of special precautions,…)may significantly affect the system performance,different above ground and underground configurations will be presented,both for new builds and existing facilities. 展开更多
关键词 Liquid leak detection ADDRESSABLE system storage TANK PIPELINE
下载PDF
Leak detection in pipelines by exclusively frequency domain method 被引量:8
8
作者 GUO XinLei YANG KaiLin GUO YongXin 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第3期743-752,共10页
A further development of exclusively inverse frequency domain method for leak detection in pipelines is presented and validated.The location and leakage can be determined by analyzing the difference of transient water... A further development of exclusively inverse frequency domain method for leak detection in pipelines is presented and validated.The location and leakage can be determined by analyzing the difference of transient water head response between the simulated and measured data in frequency domain.The transient signals are generated by portion sharp closure of a valve from the small constant opening and it needs only a few meters of water.The discrete boundary conditions and observation data are both transformed in frequency domain by Laplace transform.Example in numerical simulation is studied for demonstration of this approach.The application of the method to an experimental pipeline confirms the analysis and illustrates successful detection of the single pipeline leak.The precalibration approach is presented to minimize the effect of data and model error and it splits the method into two parts.One uses data from a known state to fit the parameters of the model and the other uses data from the current state for the fitting of leak parameters using the now calibrated model.Some important practical parameters such as wave speed,friction in steady and unsteady state and the adaptability of the method are discussed.It was found that the nonlinearity errors associated with valve boundary condition could be prevented by consideration of the induced flow perturbation curve shape. 展开更多
关键词 pipelines leak detection transient flow FREQUENCY FRICTION ALGORITHM
原文传递
Demand-Driven Memory Leak Detection Based on Flow-and Context-Sensitive Pointer Analysis 被引量:2
9
作者 王戟 马晓东 +2 位作者 董威 徐厚峰 刘万伟 《Journal of Computer Science & Technology》 SCIE EI CSCD 2009年第2期347-356,共10页
We present a demand-driven approach to memory leak detection algorithm based on flow- and context-sensitive pointer analysis. The detection algorithm firstly assumes the presence of a memory leak at some program point... We present a demand-driven approach to memory leak detection algorithm based on flow- and context-sensitive pointer analysis. The detection algorithm firstly assumes the presence of a memory leak at some program point and then runs a backward analysis to see if this assumption can be disproved. Our algorithm computes the memory abstraction of programs based on points-to graph resulting from flow- and context-sensitive pointer analysis. We have implemented the algorithm in the SUIF2 compiler infrastructure and used the implementation to analyze a set of C benchmark programs. The experimental results show that the approach has better precision with satisfied scalability as expected. 展开更多
关键词 flow-sensitive memory leak detection demand-driven static analysis
原文传递
Leakage Detection in Water Distribution Network Based on a New Heuristic Genetic Algorithm Model 被引量:4
10
作者 Ali Nasirian Mahmoud F. Maghrebi Siavash Yazdani 《Journal of Water Resource and Protection》 2013年第3期294-303,共10页
The leakage control is an important task, because it is associated with some problems such as economic loss, safety concerns, and environmental damages. The pervious methods which have already been devised for leakage... The leakage control is an important task, because it is associated with some problems such as economic loss, safety concerns, and environmental damages. The pervious methods which have already been devised for leakage detection are not only expensive and time consuming, but also have a low efficient. As a result, the global leakage detection methods such as leak detection based on simulation and calibration of the network have been considered recently. In this research, leak detection based on calibration in two hypothetical and a laboratorial networks is considered. Additionally a novel optimization method called step-by-step elimination method (SSEM) combining with a genetic algorithm (GA) is introduced to calibration and leakage detection in networks. This method step-by-step detects and eliminates the nodes that provide no contribution in leakage among uncertain parameters of calibration of a network. The proposed method initiates with an ordinary calibration for a studied network, follow by elimination of suspicious nodes among adjusted parameters, then, the network is re-calibrated. Finally the process is repeated until the numbers of unknown demands are equal to the desired numbers or the exact leakage locations and values are determined. These investigations illustrate the capability of this method for detecting the locations and sizes of leakages. 展开更多
关键词 CALIBRATION SSEM WATER DISTRIBUTION leak detection GENETIC ALGORITHM
下载PDF
Combined Endoscopic Transanal Vacuum-Assisted Rectal Drainage:A Novel Therapy for Colorectal Anastomotic Leak after TME for Cancer 被引量:1
11
作者 Mario Martinotti Valerio Ranieri +4 位作者 Elena Iiritano Teresa Staiano Roberto Dusi Ernesto Laterza Federico Buffoli 《Surgical Science》 2014年第10期467-470,共4页
Introduction: Low colorectal and colo-anal anastomosis leakage after anterior resection of rectum occurs in up to 24% of cases. Leak is the main cause of morbidity and mortality in postoperative period and can result ... Introduction: Low colorectal and colo-anal anastomosis leakage after anterior resection of rectum occurs in up to 24% of cases. Leak is the main cause of morbidity and mortality in postoperative period and can result in a permanent stoma in up to 25% of cases. Loop ileostomy or colostomy does not reduce the percentage of fistulas, but reduces flow rate. Conservative management imply long times to heal. Endosponge&reg;system (B. Braun Aesculap AG, Germany) was recently acquired in clinical practice. This system accelerates healing process through vacuum creation, removal of fluids and edema, infection control, local increase of blood flow and stimulation of granulation tissue formation. The device consists of a cylindrical polyurethane sponge, with 400 to 600 micron pores, standard dimension of 7 cm, which can be cut to fit the estimated size of the abscess cavity. The drain tube is connected to a Redyrob Trans Plus&reg;bottle which exerts a constant suction during the therapy. Materials and Methods: From November 2012 and March 2014 four patients were treated with Endosponge&reg;system, all of them underwent operation of anterior resection of rectum for cancer and developed anastomotic leakage during postoperative course. All patients had loop ileostomy, none presented signs of sepsis. The Endosponge&reg;system was then placed endoscopically. In all cases, after the first placing, the authors utilized sterile foam dressing from negative pressure wound therapy kit, tailored to better fill the abscess cavity and connected with Redyrob Trans Plus?bottle. Device changes were performed every 5 - 7 days, according to the size of the cavity and the amount of secretions produced. The treatment was started during hospitalization first and then continued as outpatient. Results: There was no mortality. The amount of secretions was related to the initial size and the degree of contamination of the abscess cavity. Antibiotic therapy was discontinued after an average of 21 days, with a range between 14 and 32 days. Complete healing was achieved in a median of 82 days (30 to 148) in all patients with good functional results, no further surgery was required. Conclusions: The results of therapy with Endosponge&reg;seem encouraging. Success of therapy is higher if initiated as soon possible after the intervention and is also related to the size of dehiscence and abscess cavity. In cases with large abscesses, it is not clear whether this new treatment leads to reduction in healing time, however, can prevent the packaging of a (often definitive) colostomy. Further studies will be able to select patients who will most benefit from the procedure. 展开更多
关键词 Endosponge^(█) Colorectal Anastomotic leak Transanal vacuum Therapy
下载PDF
Development and Application of Methane Leakage Monitoring System for Gas Transmission Pipeline
12
作者 Qijun Wang Shiqi Wei 《Journal of Electronic Research and Application》 2021年第6期44-49,共6页
Oil and gas pipeline transportation,as a relatively safe way of oil and gas transportation,undertakes most of the transportation tasks of crude oil and natural gas.Oil and gas pipeline accidents affect a wide range of... Oil and gas pipeline transportation,as a relatively safe way of oil and gas transportation,undertakes most of the transportation tasks of crude oil and natural gas.Oil and gas pipeline accidents affect a wide range of consequences.Therefore,the oil and gas pipeline leakage detection is paid more and more attention.In this paper,ultra-low power methane gas sensor is selected to collect methane gas concentration in the air,and wireless network technology is used to build a wireless network sensor system with 4G function.Through the sensor distribution along the pipeline,it can intuitively and accurately judge whether there is a micro-leakage in the pipeline,and understand the diffusion situation after the leakage.The sensor system has high reliability and stability,and has high value of popularization and application. 展开更多
关键词 Oil and gas pipeline leak detection Ultra-low power consumption Methane gas sensor
下载PDF
Oil/Gas Pipeline Leak Inspection and Repair in Underwater Poor Visibility Conditions: Challenges and Perspectives 被引量:1
13
作者 Agbakwuru Jasper 《Journal of Environmental Protection》 2012年第5期394-399,共6页
Mechanical pressure clamps are examples of innovative tools commonly used in the oil and gas industry for arresting leaks from damaged oil and gas pipelines. However, if leaks result from pipeline rupture, clamps are ... Mechanical pressure clamps are examples of innovative tools commonly used in the oil and gas industry for arresting leaks from damaged oil and gas pipelines. However, if leaks result from pipeline rupture, clamps are not usually recommended. It is therefore obvious that inspection of the leaking pipeline is very crucial in deciding the strategy for repair. For subsea pipelines where underwater poor visibility is pronounced, this important aspect of the pipeline repair process becomes difficult to implement. The result is a repair-leak-repair cycle. This challenge is commonly found in repairs of old pipelines in unclear water conditions. Old pipelines and their vulnerability to fractures that often lead to ruptures are discussed. In this paper, the challenges and technologies available for visualisation and examination in such unclear water conditions are discussed. There appears to be a gap in the existing pipeline integrity management system with respect to inspection and repair of pipelines in unclear water conditions. This gap needs to be filled in order to minimise spills and pollution. For pipelines installed in unclear water condition, a perspective is suggested to extend the capability of existing remotely operated vehicles to employ the use of clear laminar water system or a related technique to provide integrity engineers and operators with close visual assess to inspect leaking pipelines and effect adequate repairs. This paper suggests that the use of optical eye as the main tool for examination remains valuable in managing the challenges in underwater pipeline repairs in unclear water condition. 展开更多
关键词 PIPELINE leakS detection SPILL Close-Visual INSPECTION PIPELINE REPAIR PIPELINE INSPECTION
下载PDF
PECVD设备Leak在线监控系统创建及应用
14
作者 金哲山 霍建宾 +2 位作者 董杰 刘晓婷 胡毓龙 《真空科学与技术学报》 EI CAS CSCD 北大核心 2019年第11期1039-1042,共4页
等离子体增强型化学气相沉积法(PECVD)设备具有高真空特点,容易发生漏气(Leak)事故,为预防事故发生,对PECVD腔室构造、成膜原理及过程进行深入分析。从原理上检讨通过光谱分析方法在线监控PECVD工艺腔室Leak的可行性,搭建了腔室在线监... 等离子体增强型化学气相沉积法(PECVD)设备具有高真空特点,容易发生漏气(Leak)事故,为预防事故发生,对PECVD腔室构造、成膜原理及过程进行深入分析。从原理上检讨通过光谱分析方法在线监控PECVD工艺腔室Leak的可行性,搭建了腔室在线监控系统。通过光谱条件的调整测试,发现Ar等离子状态下,Leak光谱和正常光谱差异最大化,更有利于Leak光谱检测,成功实现Leak在线检测,在行业内首次实现PECVD真空腔室在线监控功能。 展开更多
关键词 真空腔室 等离子体增强型化学气相沉积 漏气 光谱检测 等离子体光谱分析仪
下载PDF
ANALYSIS OF FIRST TRANSIENT PRESSURE OSCILLATION FOR LEAKDETECTION IN A SINGLE PIPELINE 被引量:10
15
作者 YANG Kai-lin LI Fu-tian WANG Tao FU hui 《Journal of Hydrodynamics》 SCIE EI CSCD 2012年第3期363-370,共8页
The leak detection is of great importance in the reliable operation and management of a pipeline system. Recently, attention is shifted to the use of the time domain or frequency domain methods based on the transient ... The leak detection is of great importance in the reliable operation and management of a pipeline system. Recently, attention is shifted to the use of the time domain or frequency domain methods based on the transient analysis. These methods sometimes require accurate pressure signals obtained during the transient period or by creating ideal conditions in testing. This paper proposes a method that does not require transient simulations over the whole or an extended period of time, but uses the first transient pressure oscillation to detect leaks. The method considers the propagation of the pressure oscillation wave created from a fast valve closure and the reflected damp wave from the leak. A leak in the pipe gives rise to reflected waves which in turn create discontinuities in the observed signal at the measurement section. The timing of the reflected damp wave and the magnitude represent the location and the size of the leak, respectively. An analytical expression is derived based on the Method Of Characteristic (MOC) for the relationship between the leakage and the reflected magnitude. The leak detection procedure based on the method is also given. Then the reliability of the method is tested on numerically simulated pressure signals and experimental pressure signals with calibrated leak parameters, and the results indicate a successful application and the promising features of the method. 展开更多
关键词 leak detection hydraulic transient pressure oscillation PIPELINE
原文传递
Application of Golay codes to distributed optical fiber sensor for long-distance oil pipeline leakage and external damage detection 被引量:7
16
作者 王延年 蒋庄德 《Chinese Optics Letters》 SCIE EI CAS CSCD 2006年第3期141-144,共4页
A new distributed optical fiber sensor system for long-distance oil pipeline leakage and external damage detection is presented. A smart and sensitive optical fiber cable is buried beneath the soil running along the o... A new distributed optical fiber sensor system for long-distance oil pipeline leakage and external damage detection is presented. A smart and sensitive optical fiber cable is buried beneath the soil running along the oil pipeline, which is sensitive to soakage of oil products and mechanical deformation and vibration caused by leaking, tampering, and mechanical impacting. The region of additional attenuation can be located based on the optical time domain reflectometry (OTDR), and the types of external disturbances can be identified according to the characteristics of transmitted optical power. The Golay codes are utilized to improve the range-resolution performance of the OTDR sub-system and offer a method to characterize the transmitted optical power in a wide range of frequency spectrum. Theoretic analysis and simulation experiment have shown that the application of Golay codes can overcome the shortcomings of the prototype based on the conventional single-pulse OTDR. 展开更多
关键词 ATTENUATION DEFORMATION leak detection Optical cables Optical fibers Pipelines SIMULATION Time domain analysis Vibrations (mechanical)
原文传递
Design of the Vacuum Feedthrough for the EAST ICRF Antenna
17
作者 杨庆喜 宋云涛 +1 位作者 武松涛 赵燕平 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第2期252-256,共5页
Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency (ICRF) antenna in EAST, along with an electro-analysis and thermal structural analysis, is pre- sented. The electric field, the voltage... Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency (ICRF) antenna in EAST, along with an electro-analysis and thermal structural analysis, is pre- sented. The electric field, the voltage standing wave ratio (VSWR) and the stresses in the vacuum feedthrough are studied. A method using the rings of oxygen-free copper as the cushion and macro- beam plasma arc welding is applied in the assembly to protect the ceramic from being damaged during welding. The vacuum leak test on the prototype of vacuum feedthrough is introduced. 展开更多
关键词 vacuum feedthrough ICRF antenna RF macro-beam plasma arc welding vacuum leak test
下载PDF
Detection and analysis of gas tightness of continuous annealing furnaces
18
作者 Hu Guangkui Song Ruhua 《Baosteel Technical Research》 CAS 2008年第1期41-45,共5页
When a cold rolled strip is being treated in a continuous annealing furnace which is full of protective gas, the gas tightness of the furnace body, the connected facilities and the gas channels become an important ind... When a cold rolled strip is being treated in a continuous annealing furnace which is full of protective gas, the gas tightness of the furnace body, the connected facilities and the gas channels become an important indicator that directly affects the product's surface quality and shows the technical level of the design, the manufacture and the installation. By considering the problems of the gas tightness of a vertical annealing furnace in the installation and maintenance, this thesis evaluates the gas tightness indicator and gas tightness related level of the furnace body and the circulation duct, while studying and analyzing the technologies of negative-pressure leak detection and sealing. 展开更多
关键词 continuous annealing furnace gas tightness leak detection
下载PDF
Role of endoscopic vacuum therapy in the management of gastrointestinal transmural defects 被引量:7
19
作者 Diogo Turiani Hourneaux de Moura Bruna Furia Buzetti Hourneaux de Moura +5 位作者 Michael A Manfredi Kelly E Hathorn Ahmad N Bazarbashi Igor Braga Ribeiro Eduardo Guimaraes Hourneaux de Moura Christopher C Thompson 《World Journal of Gastrointestinal Endoscopy》 CAS 2019年第5期329-344,共16页
A gastrointestinal(GI) transmural defect is defined as total rupture of the GI wall,and these defects can be divided into three categories: perforations,leaks,and fistulas. Surgical management of these defects is usua... A gastrointestinal(GI) transmural defect is defined as total rupture of the GI wall,and these defects can be divided into three categories: perforations,leaks,and fistulas. Surgical management of these defects is usually challenging and may be associated with high morbidity and mortality rates. Recently,several novel endoscopic techniques have been developed,and endoscopy has become a firstline approach for therapy of these conditions. The use of endoscopic vacuum therapy(EVT) is increasing with favorable results. This technique involves endoscopic placement of a sponge connected to a nasogastric tube into the defect cavity or lumen. This promotes healing via five mechanisms,including macrodeformation,microdeformation,changes in perfusion,exudate control,and bacterial clearance,which is similar to the mechanisms in which skin wounds are treated with commonly employed wound vacuums. EVT can be used in the upper GI tract,small bowel,biliopancreatic regions,and lower GI tract,with variable success rates and a satisfactory safety profile. In this article,we review and discuss the mechanism of action,materials,techniques,efficacy,and safety of EVT in the management of patients with GI transmural defects. 展开更多
关键词 GASTROINTESTINAL ENDOSCOPY Endoscopic vacuum therapy Negative pressure therapy FISTULA leak PERFORATION Defect
下载PDF
In-Line Inspection of Pipeline Defects Detection Using Ring-Type Laser 被引量:2
20
作者 Mathivanan Durai Yang-Min Hsu Ho Chang 《World Journal of Engineering and Technology》 2021年第3期589-603,共15页
Pipeline plays a vital role in transporting fluids like oils, water, and petrochemical substances for longer distances. Based on the materials they carry</span><span style="white-space:normal;font-size:1... Pipeline plays a vital role in transporting fluids like oils, water, and petrochemical substances for longer distances. Based on the materials they carry</span><span style="white-space:normal;font-size:10pt;font-family:"">,</span><span style="white-space:normal;font-size:10pt;font-family:""> prolonged usage may cause the initiation of defects in the pipeline. These defects occur due to the formed salt deposits, chemical reaction happens between the inner surface and the transferring substance, prevailing environmental conditions, etc. These defects, if not identified earlier may lead to significant losses to the industry. In this work, an in-line inspection system utilizes the nondestructive way for analyzing the internal defects in the petrochemical pipeline. This system consists of a pipeline inspection robot having two major units namely the visual inspection unit and the power carrier unit. The visual inspection unit makes use of a ring-type laser diode and the camera. The laser diode serves as a light source for capturing good quality images of inspection. This unit is controlled by the Arduino in the power carrier unit which provides the necessary movement throughout the pipe. The inspected images captured by the camera are further processed with the aid of NI vision assistant software. After applying the processing function parameters provided by this software, the defect location can be clearly visualized with high precision. Three sets of defects are introduced in a Polylactide (PLA) pipe based on its position and angle along the circumference of the pipe. Further, this robot system serves as a real-time interactive image synchronization system for acquiring the inspected images. By comparing the actual and calculated defect size, the error percentage obtained was less than 5%. 展开更多
关键词 Pipeline Robotic System Ring-Type Laser Vision Assistant Image Pro-cessing leak Holes detection Nondestructive Testing
下载PDF
上一页 1 2 86 下一页 到第
使用帮助 返回顶部