Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fa...Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fault analysis and protection.The essay mainly studies and designs large water pump motor′s real time vibration monitoring and fault diagnosis system.The essay completes the systems project design,the establishment of the system and performance test.Eddy-currentsensor,XM-120 vibration module,XM-320 axial translation module,XM-362 temperature module,XM-360 process amount module and XM-500 gateway module are used to measure the axial vibration and displacement of main motors.Laboratory tests prove that the system can meet the requirements of motor vibration monitoring.展开更多
The positive pressure between pistonwall and piston hole of inner curve water hydraulic motor’s piston pairs is analyzed.The flow field of the piston pairs is numerically calculated and analyzed by the use of computa...The positive pressure between pistonwall and piston hole of inner curve water hydraulic motor’s piston pairs is analyzed.The flow field of the piston pairs is numerically calculated and analyzed by the use of computational fluid dynamics method.The pressure and velocity distribution of flow field at different clearance is analyzed in the paper.The results show that when the clearance is 4-8 μm,with the increase of clearance,the negative pressure and the velocity of piston chamber decrease significantly,the velocity and leakage flow of the clearance increase.However,when the clearance is 10 μm,the negative pressure and the velocity of plunger chamber increase suddenly.By comprehensive analysis,the cylinder annular clearance should be controlled to be near 8 μm.展开更多
In the last few decades, several monitoring systems integrated with water level detection have been the major research focus. Production boost and its sustainability depend mainly on sustainable water supply, measurin...In the last few decades, several monitoring systems integrated with water level detection have been the major research focus. Production boost and its sustainability depend mainly on sustainable water supply, measuring water level, and avoiding waste of water is an essential task for all stakeholders. Therefore, the aim of this paper is to design and implement a mobile phone-based remote control. This will be applied to control the operation of a submersible motor in a water tank. The water level in the tank is detected and the device remotely turns the motor pump on/off. The design process is accomplished by developing an android application that works on GSM technology to manage the filling of water tank. An AT89C51 microcontroller is used for the desired programming. At the transmitting end, sensor is used for level detection and GSM module is used to send the information to user. According to this information, user controls the on/off operation of the pump. A SIM card is required for its operation and it works on attention (AT) commands. After the design and implementation of the device, the test results showed that all features of the device worked properly, and the device functions exactly as expected. More significantly, the paper has shown that ultrasonic sensors can be used to determine the level of water in a water tank and a GSM module can be used to control a submersible pump. The design and implementation of this device can help to reduce waste of time and power. Ultimately, it avoids water wastage thereby ensuring availability, conservation, and sustainability of water supply.展开更多
The main purpose of this paper is to design and model a water-pumping system using a submersible multi-stage centrifugal pump driven by a three-phase induction motor. The system is intended for pumping water to the su...The main purpose of this paper is to design and model a water-pumping system using a submersible multi-stage centrifugal pump driven by a three-phase induction motor. The system is intended for pumping water to the surface from a deep well using three power supply systems: a general network, a photo-voltaic (PV) system, and a PV system with a battery bank. These systems are used to compare two three-phase induction motors—namely, a motor with a drive and another one without a drive. The systems dynamic models are simulated in MATLAB/Simulink and the results compared with the manufacturer’s data for validation purposes. The simulation results generally show system dynamics and expected performance over a range of operation.展开更多
This paper has introduced the developments of water hydraulic axial piston equipments. According to the effects of physicochemical properties of water on water hydraulic components, a novel valve plate for water hydra...This paper has introduced the developments of water hydraulic axial piston equipments. According to the effects of physicochemical properties of water on water hydraulic components, a novel valve plate for water hydraulic axial motor has been put forward, whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely. The material screening experiment of valve plate is done on the test rig. Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied. The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively. It is evident that the appropriate structure should change the wear status between matching pairs and reduces the wear and specific pressure of the matching pairs. The specimen with the new type valve plate is used in a tool system.展开更多
The number of interurban and urban-rural travelers in the city of Yaounde has recently exceeded one hundred thousand per year, yet surprisingly few studies have assessed travelers’ behavior, illness, and risk factors...The number of interurban and urban-rural travelers in the city of Yaounde has recently exceeded one hundred thousand per year, yet surprisingly few studies have assessed travelers’ behavior, illness, and risk factors in a sanitary risks setting. Particularly scarce are surveys of data spanning travel, return, and follow-up of the same cohort in traveling agencies and parks. This study examines behavior and illness among travelers moving from Yaounde to other urban and rural areas of Cameroon and beyond. Patterns of behavior connected to a type of travel and illness are characterized in this study so as to identify risks factors and provide background data for pre-travel advice in our traveling agencies. Assessing the susceptibility that imported cases could pose to the national response to infectious diseases depends both on public health, health services and infrastructures. The six agencies assessed: Nvan, Mokolo, Tongolo, Biyem Assi, Mimbowman and Etoudi reveal that the sanitary infrastructures for faecal and urinary disposal are not sufficient and more so, some agencies do not keep enough cleanliness, let alone provide adequate hand washing material as prescribed by national and international concerns to combat the global health challenges. This could be an impediment to travellers going out or inside of the city, and could be a preponderant mechanism for the spread of infectious disease as presented by the infectious diseases isolated and identified in the health districts around the travelling agencies.展开更多
目的探讨滋水涵木针法联合头穴透刺治疗卒中后上肢运动功能障碍的疗效。方法选取2020年9月—2022年2月医院治疗的卒中后上肢运动功能障碍患者100例,随机分为对照组(53例,头穴透刺疗法)和观察组(47例,滋水涵木针法联合头穴透刺疗法),对...目的探讨滋水涵木针法联合头穴透刺治疗卒中后上肢运动功能障碍的疗效。方法选取2020年9月—2022年2月医院治疗的卒中后上肢运动功能障碍患者100例,随机分为对照组(53例,头穴透刺疗法)和观察组(47例,滋水涵木针法联合头穴透刺疗法),对比两组治疗后临床疗效、Fugl-Meyer运动功能评分上肢部分(Fugl-Meyer assessment-upper extremity,FMA-UE)评分、改良Barthel指数(modified Barthel index,MBI)评分和沃尔夫运动功能测试(Wolf motor function test,WMFT)评分、Brunnstrom偏瘫上肢肌力分级及运动诱发电位皮质潜伏期(cortical latency,CL)和中枢运动传导时间(central motor conduction time,CMCT)值变化。结果观察组治疗有效率较对照组明显较高(P<0.05);两组治疗后FMA-UE评分、MBI评分和WMFT评分较治疗前均明显升高(P<0.05),且观察组较对照组升高更显著(P<0.05);治疗前两组Brunnstrom偏瘫上肢肌力分级间差异无统计学意义(P>0.05);治疗后两组Brunnstrom偏瘫上肢肌力分级较治疗前显著改善(P<0.05);且观察组与对照组相比较改善更明显(P<0.05);两组治疗后CL和CMCT值较治疗前显著降低(P<0.05);且观察组降低更明显(P<0.05)。结论采用滋水涵木针法联合头穴透刺治疗卒中后上肢运动功能障碍具有较好的疗效,能够改善上肢运动功能,提高上肢肌力。展开更多
文摘Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fault analysis and protection.The essay mainly studies and designs large water pump motor′s real time vibration monitoring and fault diagnosis system.The essay completes the systems project design,the establishment of the system and performance test.Eddy-currentsensor,XM-120 vibration module,XM-320 axial translation module,XM-362 temperature module,XM-360 process amount module and XM-500 gateway module are used to measure the axial vibration and displacement of main motors.Laboratory tests prove that the system can meet the requirements of motor vibration monitoring.
基金Supported by the National Natural Science Foundation of China (No.51505111)China Postdoctoral Science Foundation (No.2020M681844)Zhejiang Province Postdoctoral Science Foundation (No.ZJ2020043)。
文摘The positive pressure between pistonwall and piston hole of inner curve water hydraulic motor’s piston pairs is analyzed.The flow field of the piston pairs is numerically calculated and analyzed by the use of computational fluid dynamics method.The pressure and velocity distribution of flow field at different clearance is analyzed in the paper.The results show that when the clearance is 4-8 μm,with the increase of clearance,the negative pressure and the velocity of piston chamber decrease significantly,the velocity and leakage flow of the clearance increase.However,when the clearance is 10 μm,the negative pressure and the velocity of plunger chamber increase suddenly.By comprehensive analysis,the cylinder annular clearance should be controlled to be near 8 μm.
文摘In the last few decades, several monitoring systems integrated with water level detection have been the major research focus. Production boost and its sustainability depend mainly on sustainable water supply, measuring water level, and avoiding waste of water is an essential task for all stakeholders. Therefore, the aim of this paper is to design and implement a mobile phone-based remote control. This will be applied to control the operation of a submersible motor in a water tank. The water level in the tank is detected and the device remotely turns the motor pump on/off. The design process is accomplished by developing an android application that works on GSM technology to manage the filling of water tank. An AT89C51 microcontroller is used for the desired programming. At the transmitting end, sensor is used for level detection and GSM module is used to send the information to user. According to this information, user controls the on/off operation of the pump. A SIM card is required for its operation and it works on attention (AT) commands. After the design and implementation of the device, the test results showed that all features of the device worked properly, and the device functions exactly as expected. More significantly, the paper has shown that ultrasonic sensors can be used to determine the level of water in a water tank and a GSM module can be used to control a submersible pump. The design and implementation of this device can help to reduce waste of time and power. Ultimately, it avoids water wastage thereby ensuring availability, conservation, and sustainability of water supply.
文摘The main purpose of this paper is to design and model a water-pumping system using a submersible multi-stage centrifugal pump driven by a three-phase induction motor. The system is intended for pumping water to the surface from a deep well using three power supply systems: a general network, a photo-voltaic (PV) system, and a PV system with a battery bank. These systems are used to compare two three-phase induction motors—namely, a motor with a drive and another one without a drive. The systems dynamic models are simulated in MATLAB/Simulink and the results compared with the manufacturer’s data for validation purposes. The simulation results generally show system dynamics and expected performance over a range of operation.
文摘This paper has introduced the developments of water hydraulic axial piston equipments. According to the effects of physicochemical properties of water on water hydraulic components, a novel valve plate for water hydraulic axial motor has been put forward, whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely. The material screening experiment of valve plate is done on the test rig. Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied. The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively. It is evident that the appropriate structure should change the wear status between matching pairs and reduces the wear and specific pressure of the matching pairs. The specimen with the new type valve plate is used in a tool system.
文摘The number of interurban and urban-rural travelers in the city of Yaounde has recently exceeded one hundred thousand per year, yet surprisingly few studies have assessed travelers’ behavior, illness, and risk factors in a sanitary risks setting. Particularly scarce are surveys of data spanning travel, return, and follow-up of the same cohort in traveling agencies and parks. This study examines behavior and illness among travelers moving from Yaounde to other urban and rural areas of Cameroon and beyond. Patterns of behavior connected to a type of travel and illness are characterized in this study so as to identify risks factors and provide background data for pre-travel advice in our traveling agencies. Assessing the susceptibility that imported cases could pose to the national response to infectious diseases depends both on public health, health services and infrastructures. The six agencies assessed: Nvan, Mokolo, Tongolo, Biyem Assi, Mimbowman and Etoudi reveal that the sanitary infrastructures for faecal and urinary disposal are not sufficient and more so, some agencies do not keep enough cleanliness, let alone provide adequate hand washing material as prescribed by national and international concerns to combat the global health challenges. This could be an impediment to travellers going out or inside of the city, and could be a preponderant mechanism for the spread of infectious disease as presented by the infectious diseases isolated and identified in the health districts around the travelling agencies.
文摘目的探讨滋水涵木针法联合头穴透刺治疗卒中后上肢运动功能障碍的疗效。方法选取2020年9月—2022年2月医院治疗的卒中后上肢运动功能障碍患者100例,随机分为对照组(53例,头穴透刺疗法)和观察组(47例,滋水涵木针法联合头穴透刺疗法),对比两组治疗后临床疗效、Fugl-Meyer运动功能评分上肢部分(Fugl-Meyer assessment-upper extremity,FMA-UE)评分、改良Barthel指数(modified Barthel index,MBI)评分和沃尔夫运动功能测试(Wolf motor function test,WMFT)评分、Brunnstrom偏瘫上肢肌力分级及运动诱发电位皮质潜伏期(cortical latency,CL)和中枢运动传导时间(central motor conduction time,CMCT)值变化。结果观察组治疗有效率较对照组明显较高(P<0.05);两组治疗后FMA-UE评分、MBI评分和WMFT评分较治疗前均明显升高(P<0.05),且观察组较对照组升高更显著(P<0.05);治疗前两组Brunnstrom偏瘫上肢肌力分级间差异无统计学意义(P>0.05);治疗后两组Brunnstrom偏瘫上肢肌力分级较治疗前显著改善(P<0.05);且观察组与对照组相比较改善更明显(P<0.05);两组治疗后CL和CMCT值较治疗前显著降低(P<0.05);且观察组降低更明显(P<0.05)。结论采用滋水涵木针法联合头穴透刺治疗卒中后上肢运动功能障碍具有较好的疗效,能够改善上肢运动功能,提高上肢肌力。