BACKGROUND:Stent migration in the hepatopancreatic duct might arise as one of the rare complications associated with biliary or pancreatic stenting.Although there are some procedures to retrieve the migrated stent,inc...BACKGROUND:Stent migration in the hepatopancreatic duct might arise as one of the rare complications associated with biliary or pancreatic stenting.Although there are some procedures to retrieve the migrated stent,including surgical,percutaneous,and endoscopic approaches,endoscopy should be attempted first because it is least invasive.This study set out to evaluate the usefulness of endoscopic retrieval of migrated biliary and pancreatic stents.METHODS:Plastic stents that migrated in the bile duct(35 patients)or pancreatic duct(2)were retrieved with endoscopic retrograde cholangiopancreatography.Devices used were snare forceps,a basket catheter,grasping forceps,biopsy forceps,a balloon catheter,and the Soehendra stent retriever.RESULTS:Endoscopic retrieval of migrated stents was performed successfully in 36(97.0%)of the 37 patients.The devices utilized for successful treatment were basket catheter(13 patients),grasping forceps(10),snare forceps(8),balloon catheter(3),biopsy forceps(1),and the Soehendra stent retriever(1).The unsuccessfully treated patient with chronic pancreatitis underwent surgery since the guide wire did not move forward due to bile duct stenosis,and there was also duodenal stenosis.One patient developed mild pancreatitis after withdrawal of the stent;the pancreatitis was relieved with conservative treatment.CONCLUSIONS:Endoscopic retrieval of migrated biliary and pancreatic stents appears to be useful because of its safety and low invasiveness.However,various forceps should be prepared for the retrieval of a migrated stent.展开更多
A digitally controlled three-dimensional gamma-scanning apparatuswas developed and used to trou- bleshoot distillation column is thepresent investigation. In a 140 mm (ID) model column, variousmalfunctional phenomena,...A digitally controlled three-dimensional gamma-scanning apparatuswas developed and used to trou- bleshoot distillation column is thepresent investigation. In a 140 mm (ID) model column, variousmalfunctional phenomena, both rate and process related conditions andstructural problems, which may be frequently encountered in theoperation of tray and packing columns, were experimentally simulatedand tested with the developed scan- ning system. The experimentalresults showed that the scanning spectra can fairly reflect thesimulated phenomena.展开更多
A new troubleshooting algorithm for solving assignment problem based on existing algorithms is proposed, and an analysis on the related theory is given. By applying the new troubleshooting algorithm to the Lagrange re...A new troubleshooting algorithm for solving assignment problem based on existing algorithms is proposed, and an analysis on the related theory is given. By applying the new troubleshooting algorithm to the Lagrange relaxation algorithm of the multi-dimensional assignment problem of data association for multi-passive-sensor multi-target location systems, and comparing the simulation results with that of the Hungarian algorithm which is the classical optimal solving algorithm, and the multi-layer ordersearching algorithm which is a sub-optimal solving algorithm, the performance and applying conditions of the new algorithm are summarized. Theory analysis and simulation results prove the effectiveness and superiority of the new algorithm.展开更多
A new method for the fast detection and evaluation of optimization potentials for separation processes is presented within this work. The method disclaims the application of difficult rigorous mathematical optimizatio...A new method for the fast detection and evaluation of optimization potentials for separation processes is presented within this work. The method disclaims the application of difficult rigorous mathematical optimization techniques by a number of different smart workarounds. The basis for the optimization is the application of different heuristics, shortcut methods and simulation studies. The method was applied to a real process in which the overall yield was improved of about 58%. Due to the new configuration an alternative control scheme containing unusual control loops was implemented.展开更多
Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching fo...Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new equipments, electronics, portable computers and software. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process engineering, chemical engineering, internal hydraulic project, nuclear engineering and field abilities are pre requisites for of any scan specialist. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This paper describes our effort on developing a new approach on the gamma scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also be accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.展开更多
With the acceleration of China's modernization, infrastructure construction is affecting the development of China's national economy. China's construction of water conservancy projects continues to increas...With the acceleration of China's modernization, infrastructure construction is affecting the development of China's national economy. China's construction of water conservancy projects continues to increase, which ushered in an opportunity for water conservancy construction. As the construction of water conservancy projects has certain complexity and systematic characteristics, the process is complicated, and the construction involves various aspects, which also means that failure problems will inevitably occur during the operation of water conservancy projects, especially the failure of automation systems is the most common, which will have a serious impact on the operation efficiency, ability and level of water conservancy projects. Therefore, corresponding troubleshooting measures must be taken, and regular and regular inspection and investigation should be carried out. Through the established algorithm and so on, the hydraulic engineering automation control system fault is eliminated, the initial fault signal of the automation control system is mined, the fault type of the automation system is effectively identified, and based on the mastery of the fault cause, a targeted fault elimination instruction is adopted. Based on this, the analysis is carried out around the automation system of water conservancy projects, and the troubleshooting strategies of the system are explored to maintain the safe operation of the whole water conservancy project, improve the application effect of the automation control system, promote the continuity of the operation of the automation control system, provide references and suggestions for the troubleshooting of the automation control of water conservancy projects, and optimize the troubleshooting methods so as to effectively eliminate the faults.展开更多
With the continuous development of distributed power sources,the number of 10kV small power sources connected to the grid is gradually increasing.It is necessary to pay attention to the relevant protection configurati...With the continuous development of distributed power sources,the number of 10kV small power sources connected to the grid is gradually increasing.It is necessary to pay attention to the relevant protection configurations and fault disconnection methods of their access systems to ensure the safe and stable operation of the local power grid in the region.This paper analyzes the relay protection configuration of a small power source connected to the power grid through an example of a 10kV energy switch station in Shanghai,at the same time,it analyzed how the fault disconnection device operates and how it cooperates with the backup automatic switch to ensure the safe and stable operation of the power grid and small power sources when faults occur on the power grid or small power source side.展开更多
Beam position monitors(BPMs)are important to monitor the beam moving steadily.Keeping the beam's normal motion is an important mission for Shanghai Synchrotron Radiation Facility.Effective diagnostic analysis is a...Beam position monitors(BPMs)are important to monitor the beam moving steadily.Keeping the beam's normal motion is an important mission for Shanghai Synchrotron Radiation Facility.Effective diagnostic analysis is an important way to accomplish this task.This paper develops a new method based on clustering analysis to diagnose the healthy of BPMs with basic running data,i.e.,the β oscillation of X and Y directions and noise data.The analysis results showed that all beam position monitors(140 BPMs)can be classified into three groups:normal group,worse performance group,and fault group,respectively.In addition,the abnormal BPMs(including worse performance)could be marked.The new method showed its ability to handle faulty BPMs and it could instruct daily maintenance.On the other hand,it will be a useful supplement for data analysis in accelerator physics.展开更多
Mobile network operators are facing many challenges to satisfy their subscribers in terms of quality of service and quality of experience provided. To achieve this goal, technological progress and scientific advances ...Mobile network operators are facing many challenges to satisfy their subscribers in terms of quality of service and quality of experience provided. To achieve this goal, technological progress and scientific advances offer good opportunities for efficiency in the management of faults occurring in a mobile network. Machine learning techniques allow systems to learn from past experiences and can predict, solutions to be applied to correct the root cause of a failure. This paper evaluates machine learning techniques and identifies the decision tree as a learning model that provides the most optimal error rate in predicting outages that may occur in a mobile network. Three machine learning techniques are presented in this study and compared with regard to accuracy. This study demonstrates that the appropriate machine learning technique improves the accuracy of the model. By using the decision tree as a machine learning model, it was possible to predict solutions to network failures, with an error rate less than 2%. In addition, the use of Machine Learning makes it possible to eliminate steps in the network failure processing chain;resulting in reduced service disruption time and improved the network availability which is a key network performance index.展开更多
The development of measurement geometry for medical X-ray computed tomography （CT） scanners was carried out from the first to the fourth-generation. This concept has also been applied for imaging of industrial proce...The development of measurement geometry for medical X-ray computed tomography （CT） scanners was carried out from the first to the fourth-generation. This concept has also been applied for imaging of industrial processes such as pipe flows or for improving design, operation, optimization and troubleshooting. Nowadays, gamma CT permits to visualize failure equipment points in three-dimensional analysis and in sections of chemical and petrochemical industries. The aim of this work is the development of the mechanical system on a third-generation industrial CT scanner to analyze laboratorial process columns which perform highly efficient separation, turning the ^6oCo, ^75Se, ^137Cs and/or ^192Ir sealed gamma-ray source（s） and the NaI（Tl） multidetector array. It also has a translation movement along the column axis to obtain as many slices of the process flow as needed. The mechanical assembly for this third-generation industrial CT scanner is comprised by strength and rigidity structural frame in stainless and carbon steels, rotating table, source shield and collimator with pneumatic exposure system, spur gear system, translator, rotary stage, drives and stepper motors. The use of suitable spur gears has given a good repeatability and high accuracy in the degree of veracity. The data acquisition boards, mechanical control interfaces, software for movement control and image reconstruction were specially development. A multiphase phantom capable to be setting with solid, liquid and gas was testing. The scanner was setting for 90 views and 19 projections for each detector totalizing 11,970 projections. Experiments to determine the linear attenuation coefficients of the phantom were carried out which applied the Lambert-Beer principle. Results showed that it was possible to distinguish between the phases even the polymethylmethacrylate and the water have very similar density and linear attenuation coefficients. It was established that the newly developed third-generation fan-beam arrangement gamma scanner unit has a good spatial resolution acceptable given the size of the used phantom in this study. The tomografic reconstruction algorithm in used 60 ~ 60 pixels images was the Alternative Minimization （AM） technique and was implemented in MATLAB and VB platforms. The mechanical system presented a good performance in terms of strength, rigidity, accuracy and repeatability with great potential to be used for education or program which dedicated to training chemical and petrochemical industry professionals and for industrial process optimization in Brazil.展开更多
Driven by economy and science and technology, internet technology has gradually developed and penetrated into all walks of life. To achieve further development, power enterprises should also conform to the requirement...Driven by economy and science and technology, internet technology has gradually developed and penetrated into all walks of life. To achieve further development, power enterprises should also conform to the requirements of the times, build a smart grid and develop a power consumption information collection system, so as to improve the stability of the power system and make the power application more in line with people's actual needs. At the same time, with the application of internet technology in the power system, the security and reliability of power supply can also be effectively improved, which is more conducive to the collection and collation of information and to provide better services for users. However, through research, it is found that due to the influence of various factors, the power users' electricity information collection system is easy to cause failures. Therefore, how to deal with these failures has also become a topic worthy of study. Based on this, this paper explores its system and failures.展开更多
The traction system provides power for the operation process of metro trains. Various faults may lead to traction blockade and the vehicles cannot be started. Corresponding train rescue measures should be taken after ...The traction system provides power for the operation process of metro trains. Various faults may lead to traction blockade and the vehicles cannot be started. Corresponding train rescue measures should be taken after the accidents, which will have a great impact on the safety and operation quality of the trains. This paper mainly analyzes the typical traction/brake command failure occurred in the early stage of a certain line of Chongqing rail transit, and the traction force can not give the failure, in order to improve the train operators fault handling judgment and handling ability, and at the same time improve the vehicle maintenance test content, to ensure the normal important functions of the vehicle.展开更多
In the oil drilling work, the main equipment to provide power is diesel engine. In the actual field work, the drilling diesel engine is often used in the very bad environment, and in the high-power operation state, it...In the oil drilling work, the main equipment to provide power is diesel engine. In the actual field work, the drilling diesel engine is often used in the very bad environment, and in the high-power operation state, it is easy to cause various faults of the diesel engine, which affects the normal work. In order to ensure the good efficiency of use and work of diesel engine, this paper analyzes the cause of failure and the method of elimination.展开更多
文摘BACKGROUND:Stent migration in the hepatopancreatic duct might arise as one of the rare complications associated with biliary or pancreatic stenting.Although there are some procedures to retrieve the migrated stent,including surgical,percutaneous,and endoscopic approaches,endoscopy should be attempted first because it is least invasive.This study set out to evaluate the usefulness of endoscopic retrieval of migrated biliary and pancreatic stents.METHODS:Plastic stents that migrated in the bile duct(35 patients)or pancreatic duct(2)were retrieved with endoscopic retrograde cholangiopancreatography.Devices used were snare forceps,a basket catheter,grasping forceps,biopsy forceps,a balloon catheter,and the Soehendra stent retriever.RESULTS:Endoscopic retrieval of migrated stents was performed successfully in 36(97.0%)of the 37 patients.The devices utilized for successful treatment were basket catheter(13 patients),grasping forceps(10),snare forceps(8),balloon catheter(3),biopsy forceps(1),and the Soehendra stent retriever(1).The unsuccessfully treated patient with chronic pancreatitis underwent surgery since the guide wire did not move forward due to bile duct stenosis,and there was also duodenal stenosis.One patient developed mild pancreatitis after withdrawal of the stent;the pancreatitis was relieved with conservative treatment.CONCLUSIONS:Endoscopic retrieval of migrated biliary and pancreatic stents appears to be useful because of its safety and low invasiveness.However,various forceps should be prepared for the retrieval of a migrated stent.
基金the Department of Research and Development, SINOPEC.
文摘A digitally controlled three-dimensional gamma-scanning apparatuswas developed and used to trou- bleshoot distillation column is thepresent investigation. In a 140 mm (ID) model column, variousmalfunctional phenomena, both rate and process related conditions andstructural problems, which may be frequently encountered in theoperation of tray and packing columns, were experimentally simulatedand tested with the developed scan- ning system. The experimentalresults showed that the scanning spectra can fairly reflect thesimulated phenomena.
基金supported by the National Natural Science Foundation of China(61170161)the Natural Science Foundation of S handong (ZR2009GM002)the Technology Projects of Shandong University (J09LG01)
文摘A new troubleshooting algorithm for solving assignment problem based on existing algorithms is proposed, and an analysis on the related theory is given. By applying the new troubleshooting algorithm to the Lagrange relaxation algorithm of the multi-dimensional assignment problem of data association for multi-passive-sensor multi-target location systems, and comparing the simulation results with that of the Hungarian algorithm which is the classical optimal solving algorithm, and the multi-layer ordersearching algorithm which is a sub-optimal solving algorithm, the performance and applying conditions of the new algorithm are summarized. Theory analysis and simulation results prove the effectiveness and superiority of the new algorithm.
文摘A new method for the fast detection and evaluation of optimization potentials for separation processes is presented within this work. The method disclaims the application of difficult rigorous mathematical optimization techniques by a number of different smart workarounds. The basis for the optimization is the application of different heuristics, shortcut methods and simulation studies. The method was applied to a real process in which the overall yield was improved of about 58%. Due to the new configuration an alternative control scheme containing unusual control loops was implemented.
文摘Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new equipments, electronics, portable computers and software. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process engineering, chemical engineering, internal hydraulic project, nuclear engineering and field abilities are pre requisites for of any scan specialist. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This paper describes our effort on developing a new approach on the gamma scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also be accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.
文摘With the acceleration of China's modernization, infrastructure construction is affecting the development of China's national economy. China's construction of water conservancy projects continues to increase, which ushered in an opportunity for water conservancy construction. As the construction of water conservancy projects has certain complexity and systematic characteristics, the process is complicated, and the construction involves various aspects, which also means that failure problems will inevitably occur during the operation of water conservancy projects, especially the failure of automation systems is the most common, which will have a serious impact on the operation efficiency, ability and level of water conservancy projects. Therefore, corresponding troubleshooting measures must be taken, and regular and regular inspection and investigation should be carried out. Through the established algorithm and so on, the hydraulic engineering automation control system fault is eliminated, the initial fault signal of the automation control system is mined, the fault type of the automation system is effectively identified, and based on the mastery of the fault cause, a targeted fault elimination instruction is adopted. Based on this, the analysis is carried out around the automation system of water conservancy projects, and the troubleshooting strategies of the system are explored to maintain the safe operation of the whole water conservancy project, improve the application effect of the automation control system, promote the continuity of the operation of the automation control system, provide references and suggestions for the troubleshooting of the automation control of water conservancy projects, and optimize the troubleshooting methods so as to effectively eliminate the faults.
文摘With the continuous development of distributed power sources,the number of 10kV small power sources connected to the grid is gradually increasing.It is necessary to pay attention to the relevant protection configurations and fault disconnection methods of their access systems to ensure the safe and stable operation of the local power grid in the region.This paper analyzes the relay protection configuration of a small power source connected to the power grid through an example of a 10kV energy switch station in Shanghai,at the same time,it analyzed how the fault disconnection device operates and how it cooperates with the backup automatic switch to ensure the safe and stable operation of the power grid and small power sources when faults occur on the power grid or small power source side.
基金Ten Thousand Talent Program and Chinese Academy of Sciences Key Technology Talent Program (No.Y91G201B01)。
文摘Beam position monitors(BPMs)are important to monitor the beam moving steadily.Keeping the beam's normal motion is an important mission for Shanghai Synchrotron Radiation Facility.Effective diagnostic analysis is an important way to accomplish this task.This paper develops a new method based on clustering analysis to diagnose the healthy of BPMs with basic running data,i.e.,the β oscillation of X and Y directions and noise data.The analysis results showed that all beam position monitors(140 BPMs)can be classified into three groups:normal group,worse performance group,and fault group,respectively.In addition,the abnormal BPMs(including worse performance)could be marked.The new method showed its ability to handle faulty BPMs and it could instruct daily maintenance.On the other hand,it will be a useful supplement for data analysis in accelerator physics.
文摘Mobile network operators are facing many challenges to satisfy their subscribers in terms of quality of service and quality of experience provided. To achieve this goal, technological progress and scientific advances offer good opportunities for efficiency in the management of faults occurring in a mobile network. Machine learning techniques allow systems to learn from past experiences and can predict, solutions to be applied to correct the root cause of a failure. This paper evaluates machine learning techniques and identifies the decision tree as a learning model that provides the most optimal error rate in predicting outages that may occur in a mobile network. Three machine learning techniques are presented in this study and compared with regard to accuracy. This study demonstrates that the appropriate machine learning technique improves the accuracy of the model. By using the decision tree as a machine learning model, it was possible to predict solutions to network failures, with an error rate less than 2%. In addition, the use of Machine Learning makes it possible to eliminate steps in the network failure processing chain;resulting in reduced service disruption time and improved the network availability which is a key network performance index.
文摘The development of measurement geometry for medical X-ray computed tomography （CT） scanners was carried out from the first to the fourth-generation. This concept has also been applied for imaging of industrial processes such as pipe flows or for improving design, operation, optimization and troubleshooting. Nowadays, gamma CT permits to visualize failure equipment points in three-dimensional analysis and in sections of chemical and petrochemical industries. The aim of this work is the development of the mechanical system on a third-generation industrial CT scanner to analyze laboratorial process columns which perform highly efficient separation, turning the ^6oCo, ^75Se, ^137Cs and/or ^192Ir sealed gamma-ray source（s） and the NaI（Tl） multidetector array. It also has a translation movement along the column axis to obtain as many slices of the process flow as needed. The mechanical assembly for this third-generation industrial CT scanner is comprised by strength and rigidity structural frame in stainless and carbon steels, rotating table, source shield and collimator with pneumatic exposure system, spur gear system, translator, rotary stage, drives and stepper motors. The use of suitable spur gears has given a good repeatability and high accuracy in the degree of veracity. The data acquisition boards, mechanical control interfaces, software for movement control and image reconstruction were specially development. A multiphase phantom capable to be setting with solid, liquid and gas was testing. The scanner was setting for 90 views and 19 projections for each detector totalizing 11,970 projections. Experiments to determine the linear attenuation coefficients of the phantom were carried out which applied the Lambert-Beer principle. Results showed that it was possible to distinguish between the phases even the polymethylmethacrylate and the water have very similar density and linear attenuation coefficients. It was established that the newly developed third-generation fan-beam arrangement gamma scanner unit has a good spatial resolution acceptable given the size of the used phantom in this study. The tomografic reconstruction algorithm in used 60 ~ 60 pixels images was the Alternative Minimization （AM） technique and was implemented in MATLAB and VB platforms. The mechanical system presented a good performance in terms of strength, rigidity, accuracy and repeatability with great potential to be used for education or program which dedicated to training chemical and petrochemical industry professionals and for industrial process optimization in Brazil.
文摘Driven by economy and science and technology, internet technology has gradually developed and penetrated into all walks of life. To achieve further development, power enterprises should also conform to the requirements of the times, build a smart grid and develop a power consumption information collection system, so as to improve the stability of the power system and make the power application more in line with people's actual needs. At the same time, with the application of internet technology in the power system, the security and reliability of power supply can also be effectively improved, which is more conducive to the collection and collation of information and to provide better services for users. However, through research, it is found that due to the influence of various factors, the power users' electricity information collection system is easy to cause failures. Therefore, how to deal with these failures has also become a topic worthy of study. Based on this, this paper explores its system and failures.
文摘The traction system provides power for the operation process of metro trains. Various faults may lead to traction blockade and the vehicles cannot be started. Corresponding train rescue measures should be taken after the accidents, which will have a great impact on the safety and operation quality of the trains. This paper mainly analyzes the typical traction/brake command failure occurred in the early stage of a certain line of Chongqing rail transit, and the traction force can not give the failure, in order to improve the train operators fault handling judgment and handling ability, and at the same time improve the vehicle maintenance test content, to ensure the normal important functions of the vehicle.
文摘In the oil drilling work, the main equipment to provide power is diesel engine. In the actual field work, the drilling diesel engine is often used in the very bad environment, and in the high-power operation state, it is easy to cause various faults of the diesel engine, which affects the normal work. In order to ensure the good efficiency of use and work of diesel engine, this paper analyzes the cause of failure and the method of elimination.
