A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless s...A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.展开更多
BACKGROUND: Timely reperfusion in ST-segment elevation myocardial infarction(STEMI)improves outcomes. System delay is that between first medical contact and reperfusion therapy,comprising prehospital and hospital comp...BACKGROUND: Timely reperfusion in ST-segment elevation myocardial infarction(STEMI)improves outcomes. System delay is that between first medical contact and reperfusion therapy,comprising prehospital and hospital components. This study aimed to characterize prehospital system delay in Singapore.METHODS: A retrospective chart review was performed for 462 consecutive STEMI patients presenting to a tertiary hospital from December 2006 to April 2008. Patients with cardiac arrest secondarily presented were excluded. For those who received emergency medical services(EMS),ambulance records were reviewed. Time intervals in the hospital were collected prospectively. The patients were divided into two equal groups of high/low prehospital system delay using visual binning technique.RESULTS: Of 462 patients, 76 received EMS and 52 of the 76 patients were analyzed. The median system delay was 125.5 minutes and the median prehospital system delay was 33.5minutes(interquartile range [IQR]=27.0, 42.0). Delay between call-received-by-ambulance and ambulance-dispatched was 2.48 minutes(IQR=1.47, 16.55); between ambulance-dispatch and arrival-at-patient-location was 8.07 minutes(IQR=1.30, 22.13); between arrival-at- and departurefrom-patient-location was 13.12 minutes(IQR=3.12, 32.2); and between leaving-patient-location to ED-registration was 9.90 minutes(IQR=1.62, 32.92). Comparing patients with prehospital system delay of less than 35.5 minutes versus more showed that the median delay between ambulancedispatch and arrival-at-patient-location was shorter(5.75 vs. 9.37 minutes, P<0.01). The median delay between arrival-at-patient-location and leaving-patient-location was also shorter(10.78 vs.14.37 minutes, P<0.01).CONCLUSION: Prehospital system delay in our patients was suboptimal. This is the first attempt at characterizing prehospital system delay in Singapore and forms the basis for improving efficiency of STEMI care.展开更多
Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have consi...Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door under blast loading were analyzed by the finite element program ABAQUS, combined with a previously developed elasto-viscoplastic rate-sensitive material model. And the effect of the surrounding rock mass and contact effect of the doorframe were also taken into account in the simulation. It is demonstrated that the strain-rate effect has considerable influence on the response of reinforced concrete blast door subjected to blast loading and must be taken into account in the analysis.展开更多
The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this pa...The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this paper. Firstly, failure components of the door are statistically analyzed, and the major failure components are determined. Secondly, failures are classified according to their impacts on operation, and methods of calculating failure mode criticality and the related coefficients are illustrated. Finally, the FMECA is detailed in the selected 12 failure modes, and the failure modes are discovered that they have the most significant effect on metro door system. The obtained results can be used for optimal design and maintenance of the metro door system.展开更多
Nowadays, the elevator has become an indispensable means of indoor transportation in people’s life, but in recent years this kind of traffic tools has caused many casualties because of the gate system fault. In order...Nowadays, the elevator has become an indispensable means of indoor transportation in people’s life, but in recent years this kind of traffic tools has caused many casualties because of the gate system fault. In order to ensure the safe and reliable operation of the elevator, the failure of elevator door system was predicted in this paper. Against the fault type of elevator door system: elevator door opened, excessive vibration when elevator door opened or closed, elevator door did not open or closed when reached the specified level. Three fault types were used as the output of the prediction model. There were 8 reasons for the failure, used them as input. A model based on particle swarm optimization (PSO) and BP neural network was established, using MATLAB to emulation;the results showed that: PSO-BP neural network algorithm was feasible in the fault prediction of the elevator door system.展开更多
One of the main construction problems in permafrost regions is protecting permafrost thermal stability. Although ventilating ducts and crushed-rock layers were successfully used in railway embankment construction, the...One of the main construction problems in permafrost regions is protecting permafrost thermal stability. Although ventilating ducts and crushed-rock layers were successfully used in railway embankment construction, their effects might not meet large-width expressway requirements. The convection-intensifying composite embankment composed of perforated ventilation ducts and crushed-rock layers was numerically studied to investigate its cooling effects. Adopting a numerical model, the temperature fields for two kinds of composite embankment with and without air doors were analyzed considering air flow and heat transfer characteristics in porous media. The results show that wind velocity in the crushed-rock zone is intensified by the perforated ventilation duct. The underlying permafrost temperature obviously decreases, and the 0 °C isotherm position rises significantly due to composite embankment. The composite embankment with air doors is more effective than that without air doors. Therefore, the new convection-intensifying composite embankment is potentially a highly efficient cooling measure for construction in permafrost regions.展开更多
The doors and windows are the throat of the building. This paper discusses the fundamental role of the doors and windows of the building, and the dominant roles such as spatial organization and control of light, and t...The doors and windows are the throat of the building. This paper discusses the fundamental role of the doors and windows of the building, and the dominant roles such as spatial organization and control of light, and to study the recessive function of windows and doors from aspects of the psychological impact, cultural significance and decoration. After exploring the characteristics of modem windows and doors, it studies the design elements of modem windows and doors and summed up the features that the initiative to make use of the environment. Basic from three levels as the basic form of design; windows and buildings, and the social and natural environment of the unified design; doors and windows to take the initiative to study the nature.展开更多
In order to study the dynamic response of the unmanned aerial vehicle cabin door opening and closing system under impact load conditions, considering the flexible treatment of mechanical components, and the system’s ...In order to study the dynamic response of the unmanned aerial vehicle cabin door opening and closing system under impact load conditions, considering the flexible treatment of mechanical components, and the system’s motion with different stiffness of energy-absorbing components, a rigid-flexible coupling model of the cabin door actuation system was established in LMS. Virtual. Motion. In Amesim, a control model of the motor was created. Through the Motion-Amesim co-simulation module, the dynamic module of the system was combined with the motor control module to complete the electromechanical coupling simulation and analyze the results. .展开更多
The robust design approach based on Taguchi＇s design of experiment （DOE） coupled with the traditional finite element analysis （FEA） is applied to the static design of a sedan door. This method aims at shortening ...The robust design approach based on Taguchi＇s design of experiment （DOE） coupled with the traditional finite element analysis （FEA） is applied to the static design of a sedan door. This method aims at shortening the design period, reducing the calculation cost and improving the competitive competence. First, the pe^ormance re- quirements, the control factors and the corresponding levels are determined to design a DOE table. Second, based on the schemes from the DOE table, sensitive control factors are distinguished from the results of the FEA method. Finally, the optimum design is chosen after comparisons and analyses of these performance response graphs. Performance results of the optimum design indicate that the application of the robust approach and FEA can greatly im- prove the quality of the door system, satisfy the requirements of products, underline the design purpose and shorten the design period.展开更多
growth in Africa, Ghana has been witnessing a surge in foreign direct investments. According to World Bank statistics, its economy grew by an average of 6 percent annually since 2005 before heading for an assessed 4.S...growth in Africa, Ghana has been witnessing a surge in foreign direct investments. According to World Bank statistics, its economy grew by an average of 6 percent annually since 2005 before heading for an assessed 4.S-percent growth this year. Foreign investments totaled over $12 billion from 1999 to 2009.展开更多
From September 13th-16th,2010,the Texworld show will be held at the Paris le Bourget exhibition centre.This show,735 weavers-which attests to the stability in the numbers of exhibitors
基金Project (No. 50607016) supported by the National Natural ScienceFoundation of China
文摘A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.
文摘BACKGROUND: Timely reperfusion in ST-segment elevation myocardial infarction(STEMI)improves outcomes. System delay is that between first medical contact and reperfusion therapy,comprising prehospital and hospital components. This study aimed to characterize prehospital system delay in Singapore.METHODS: A retrospective chart review was performed for 462 consecutive STEMI patients presenting to a tertiary hospital from December 2006 to April 2008. Patients with cardiac arrest secondarily presented were excluded. For those who received emergency medical services(EMS),ambulance records were reviewed. Time intervals in the hospital were collected prospectively. The patients were divided into two equal groups of high/low prehospital system delay using visual binning technique.RESULTS: Of 462 patients, 76 received EMS and 52 of the 76 patients were analyzed. The median system delay was 125.5 minutes and the median prehospital system delay was 33.5minutes(interquartile range [IQR]=27.0, 42.0). Delay between call-received-by-ambulance and ambulance-dispatched was 2.48 minutes(IQR=1.47, 16.55); between ambulance-dispatch and arrival-at-patient-location was 8.07 minutes(IQR=1.30, 22.13); between arrival-at- and departurefrom-patient-location was 13.12 minutes(IQR=3.12, 32.2); and between leaving-patient-location to ED-registration was 9.90 minutes(IQR=1.62, 32.92). Comparing patients with prehospital system delay of less than 35.5 minutes versus more showed that the median delay between ambulancedispatch and arrival-at-patient-location was shorter(5.75 vs. 9.37 minutes, P<0.01). The median delay between arrival-at-patient-location and leaving-patient-location was also shorter(10.78 vs.14.37 minutes, P<0.01).CONCLUSION: Prehospital system delay in our patients was suboptimal. This is the first attempt at characterizing prehospital system delay in Singapore and forms the basis for improving efficiency of STEMI care.
基金Supported by National Natural Science Foundation of China(No.50525825)
文摘Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door under blast loading were analyzed by the finite element program ABAQUS, combined with a previously developed elasto-viscoplastic rate-sensitive material model. And the effect of the surrounding rock mass and contact effect of the doorframe were also taken into account in the simulation. It is demonstrated that the strain-rate effect has considerable influence on the response of reinforced concrete blast door subjected to blast loading and must be taken into account in the analysis.
文摘The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this paper. Firstly, failure components of the door are statistically analyzed, and the major failure components are determined. Secondly, failures are classified according to their impacts on operation, and methods of calculating failure mode criticality and the related coefficients are illustrated. Finally, the FMECA is detailed in the selected 12 failure modes, and the failure modes are discovered that they have the most significant effect on metro door system. The obtained results can be used for optimal design and maintenance of the metro door system.
文摘Nowadays, the elevator has become an indispensable means of indoor transportation in people’s life, but in recent years this kind of traffic tools has caused many casualties because of the gate system fault. In order to ensure the safe and reliable operation of the elevator, the failure of elevator door system was predicted in this paper. Against the fault type of elevator door system: elevator door opened, excessive vibration when elevator door opened or closed, elevator door did not open or closed when reached the specified level. Three fault types were used as the output of the prediction model. There were 8 reasons for the failure, used them as input. A model based on particle swarm optimization (PSO) and BP neural network was established, using MATLAB to emulation;the results showed that: PSO-BP neural network algorithm was feasible in the fault prediction of the elevator door system.
基金the financial support of the National Natural Science Foundation of China (No. 41121061)the National Basic Research Program (973) of China (Nos. 2012CB026101 and 2011CB013505)+1 种基金the Western Project Program of the Chinese Academy of Sciences (No. KZCX2-XB3-19)the Open Fund of State Key Laboratory of Frozen Soil Engineering (No. SKLFSE201209)
文摘One of the main construction problems in permafrost regions is protecting permafrost thermal stability. Although ventilating ducts and crushed-rock layers were successfully used in railway embankment construction, their effects might not meet large-width expressway requirements. The convection-intensifying composite embankment composed of perforated ventilation ducts and crushed-rock layers was numerically studied to investigate its cooling effects. Adopting a numerical model, the temperature fields for two kinds of composite embankment with and without air doors were analyzed considering air flow and heat transfer characteristics in porous media. The results show that wind velocity in the crushed-rock zone is intensified by the perforated ventilation duct. The underlying permafrost temperature obviously decreases, and the 0 °C isotherm position rises significantly due to composite embankment. The composite embankment with air doors is more effective than that without air doors. Therefore, the new convection-intensifying composite embankment is potentially a highly efficient cooling measure for construction in permafrost regions.
文摘The doors and windows are the throat of the building. This paper discusses the fundamental role of the doors and windows of the building, and the dominant roles such as spatial organization and control of light, and to study the recessive function of windows and doors from aspects of the psychological impact, cultural significance and decoration. After exploring the characteristics of modem windows and doors, it studies the design elements of modem windows and doors and summed up the features that the initiative to make use of the environment. Basic from three levels as the basic form of design; windows and buildings, and the social and natural environment of the unified design; doors and windows to take the initiative to study the nature.
文摘In order to study the dynamic response of the unmanned aerial vehicle cabin door opening and closing system under impact load conditions, considering the flexible treatment of mechanical components, and the system’s motion with different stiffness of energy-absorbing components, a rigid-flexible coupling model of the cabin door actuation system was established in LMS. Virtual. Motion. In Amesim, a control model of the motor was created. Through the Motion-Amesim co-simulation module, the dynamic module of the system was combined with the motor control module to complete the electromechanical coupling simulation and analyze the results. .
文摘The robust design approach based on Taguchi＇s design of experiment （DOE） coupled with the traditional finite element analysis （FEA） is applied to the static design of a sedan door. This method aims at shortening the design period, reducing the calculation cost and improving the competitive competence. First, the pe^ormance re- quirements, the control factors and the corresponding levels are determined to design a DOE table. Second, based on the schemes from the DOE table, sensitive control factors are distinguished from the results of the FEA method. Finally, the optimum design is chosen after comparisons and analyses of these performance response graphs. Performance results of the optimum design indicate that the application of the robust approach and FEA can greatly im- prove the quality of the door system, satisfy the requirements of products, underline the design purpose and shorten the design period.
文摘growth in Africa, Ghana has been witnessing a surge in foreign direct investments. According to World Bank statistics, its economy grew by an average of 6 percent annually since 2005 before heading for an assessed 4.S-percent growth this year. Foreign investments totaled over $12 billion from 1999 to 2009.
文摘From September 13th-16th,2010,the Texworld show will be held at the Paris le Bourget exhibition centre.This show,735 weavers-which attests to the stability in the numbers of exhibitors
