The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
M L Porter - One of the best experts on this subject based on the ideXlab platform.
-
ACETABULAR CEMENT PRESSURISATION: AN IN-VITRO STUDY OF DIFFERENT DESIGNS OF ACETABULAR CEMENT PressuriserS
2008Co-Authors: F. Wadia, M. H. A Malik, J Leonard, M L PorterAbstract:A secure bone cement interface between the acetabulum and the cement mantle of the hip socket is an important requirement for the long-term success of a cemented hip arthroplasty. Cement pressurisation after bone bed cleaning enables cement to penetrate interstices of cancellous bone forming a superior fixation strength. We designed an in-vitro experiment to evaluate the performance of the Exeter, Depuy T-handle and a plunger-type Pressurisers using two parameters: cement penetration and cement pressurisation. The deformation of the flexible pressure head of the DePuy model produced a cement mantle, which is thick at the pole but tapered at its rim and variable in the amount of penetration produced (range 2–8mm) for an estimated similar force. Pressures of up to 60KPa were generated throughout the model acetabulum. The Exeter Pressuriser was found to produce cement mantles more compatible with a socket. However, the test results show a wide variation in cement penetration occurring for what was estimated to be a similar applied force (3mm to 9mm at the pole and 5mm to 9mm at the rim). It was also shown to have the disadvantage of causing widely dissimilar pressures at the pole and the rim. The plunger protrusion required to produce 5mm cement penetration was found to be 7.5mm. Since this protrusion can be monitored and controlled by the operator, a cement intrusion of 5mm +/−1mm was found to be reproducible with the plunger-type device. The maximum variation in intrusion between rim and pole was 1 mm. Maximin pressures of 70KPa were generated. We have presented experimental evidence that suggests that a plunger type of acetabular cement Pressuriser may provide a more consistently reproducible level of pressurisation leading to optimal cement penetration.
-
Cement pressurisation in the acetabulum
International Orthopaedics, 2006Co-Authors: F. Wadia, D Leonard, M. H. A Malik, M L PorterAbstract:La pressurisation du ciment est une étape importante dans la prothèse totale de hanche qui peut déterminer une bonne intégration, à long terme, des implants, notamment à l’interface ciment-os. Le but de notre étude est d’évaluer les performances d’un nouvel appareil destiné à Pressuriser le ciment, en comparaison avec l’appareil préexistant, cette comparaison étant réalisée au cours d’une étude expérimentale in vitro avec étude de deux paramètres, la pénétration et la pressurisation du ciment. Une cupule en polypropylène a été fabriquée comme modèle d’accétabulum. Nous avons ensuite mesuré la pénétration et la pressurisation du ciment, nous avons utilisé trois appareils, le porte cupule Depuy, l’appareil d’Exeter et notre propre appareillage. Résultats : l’intrusion du ciment dans les capillaires avec le porte cupule Depuy a été de 2 à 8 mm, avec l’appareil d’Exeter de 3 à 9 mm et avec notre nouvel appareillage de 4 à 6 mm. Le type de pression avec l’appareil porte cupule Depuy a été de 60 kPa alors qu’il était de 70 kPa avec notre nouvel appareillage. En conclusion : la pénétration moyenne avec notre nouvel appareillage a été nettement améliorée si on la compare aux autres types d’appareillage. Cette pénétration a été plus uniforme que se soit au pourtour de la cupule ou au niveau des pôles. Cement pressurisation is an important step in total hip arthroplasty that determines the long-term integration at the cement-bone interface. Our aim was to evaluate the performance of a new Pressuriser designed by us against the standard existing Pressurisers in an in vitro experimental set-up using two parameters: cement penetration and cement pressurisation. A polypropylene cup model was designed to represent the acetabulum. DePuy’s T-handle, Exeter and our own plunger type Pressuriser were each tested for cement pressurisation in this acetabular model. Cement penetration and pressures were measured. The cement intrusion into the capillaries with the DePuy Pressuriser was found to vary between 2 and 8 mm (mean: 5 mm at the pole and 4.6 mm at the rim), with the Exeter Pressuriser it varied between 3 and 9 mm (mean: 5.8 mm at the pole and 7.8 mm at the rim) and with the plunger type Pressuriser it varied between 4 and 6 mm (mean 5.2 mm at the pole and 4.8 mm at the rim). The peak pressure achieved with the DePuy Pressuriser was 60 kPa whereas it was 70 kPa with the plunger type Pressuriser. The mean penetration with the plunger type Pressuriser was found to be better than the other types. The penetration was found to be more uniform with equal penetration at the rim as well as at the pole.
-
Cement pressurisation in the acetabulum.
International orthopaedics, 2006Co-Authors: F. Wadia, D Leonard, Mohammad Azad Malik, M L PorterAbstract:Cement pressurisation is an important step in total hip arthroplasty that determines the long-term integration at the cement-bone interface. Our aim was to evaluate the performance of a new Pressuriser designed by us against the standard existing Pressurisers in an in vitro experimental set-up using two parameters: cement penetration and cement pressurisation. A polypropylene cup model was designed to represent the acetabulum. DePuy’s T-handle, Exeter and our own plunger type Pressuriser were each tested for cement pressurisation in this acetabular model. Cement penetration and pressures were measured. The cement intrusion into the capillaries with the DePuy Pressuriser was found to vary between 2 and 8 mm (mean: 5 mm at the pole and 4.6 mm at the rim), with the Exeter Pressuriser it varied between 3 and 9 mm (mean: 5.8 mm at the pole and 7.8 mm at the rim) and with the plunger type Pressuriser it varied between 4 and 6 mm (mean 5.2 mm at the pole and 4.8 mm at the rim). The peak pressure achieved with the DePuy Pressuriser was 60 kPa whereas it was 70 kPa with the plunger type Pressuriser. The mean penetration with the plunger type Pressuriser was found to be better than the other types. The penetration was found to be more uniform with equal penetration at the rim as well as at the pole.
-
A NEW INSTRUMENT FOR IMPROVING CEMENT PRESSURISATION IN THE ACETABULUM
2004Co-Authors: N Pradhan, A K Gambhir, D Leonard, M L PorterAbstract:A secure bone/cement interface at the bone cement junction is an important requirement for the long-term success in the cemented hip arthroplasty. Cementing techniques have evolved and now involve pressurisation of the acetabulum and femur. It can be difficult to get a complete rim seal and hence adequate pressurisation due to the unique anatomy of the acetabulum and the contyloid notch. Several acetabular Pressurisers are commercially available. We have developed an instrument for controlled and reproducible cement pressurisation in the acetabulum before socket insertion. It is a T-bar incorporating a central plunger, which protrudes from an outer sleeve when force is applied. The protrusion of the central plunger and hence the amount of force applied can be limited by a stop-sleeve. A laboratory saw bone model was designed to assess this system and compare it with two existing Pressurisers. A polypropylene model of the acetabulum was used. Included in the model were two 1.3mm diameter capillary outlets, one at its pole and one at a point close to its rim opposite the cotyloid notch. Water was free to flow through the capillaries at a pressure of 13.5” WG to represent blood flow. 5 test per Pressuriser were performed. CMW 1 Gentamicin bone cement was mixed as per manufacturers instruction in a Vacuum Mix system. The cement was then pressurised using one of three systems; the Depuy T handle Pressuriser, the Exeter Pressuriser and our new instrument. The cement mantle produced with the Depuy T-handle and the Exeter Pressuriser was thicker at the pole than the rim and the cement intrusion was not consistent nor reproducible. The new pressurizer produced a cement mantle equal at the pole and the rim to within 1mm. A reproducible cement mantle compatible to the shape of the socket and with cement intrusion of 5mm (+/− 1mm) could be achieved. We recommend the use of this Pressuriser.
Fuyu Zhao - One of the best experts on this subject based on the ideXlab platform.
-
A fuzzy-logic-based pressure setpoint modification method for pressurized water reactor pressurizers
Annals of Nuclear Energy, 2020Co-Authors: Pengfei Wang, Jiashuang Wan, Fuyu ZhaoAbstract:Abstract For pressurized water reactors, the pressurizer pressure is expected to be maintained constant to limit adverse impacts on the reactor due to pressure variations. To achieve this, a constant pressure setpoint is usually adopted in the pressurizer pressure control system. But it may not guarantee satisfactory pressure control performances especially under severe transient conditions. A feasible solution may be adjusting the pressure setpoint during transient processes and then restoring it to the initial value. For this purpose, the paper proposes a fuzzy-logic-based pressure setpoint modification (FPSM) method for pressurizers. A simulation platform was developed in MATLAB/Simulink implementing a nonequilibrium three-region pressurizer model, the pressure and waterlevel control systems and the FPSM system. Simulation studies of the AP1000 pressurizer during typical load change transients were performed, and responses of the pressurizer implementing the FPSM system are compared with those employing constant pressure setpoint to demonstrate feasibility and effectiveness of the system.
-
Mathematical modeling of a pressurizer in a pressurized water reactor for control design
Applied Mathematical Modelling, 2019Co-Authors: Pengfei Wang, Xinyu Wei, Fuyu ZhaoAbstract:Abstract A pressurizer is a key equipment to ensure the safe operation of a pressurized water reactor by maintaining the reactor coolant system pressure within allowed tolerances. In this paper, a nonequilibrium three-region pressurizer model for the pressurized water reactor was developed first base on the basic conservation laws of mass and energy for the steam and water in the pressurizer. Then the nonlinear model was linearized to introduce the transfer function models of the pressurizer during insurge and outsurge transients for the controller design of a small pressurized water reactor pressurizer. Based on the developed transfer function models, the closed-loop pressurizer pressure and water level control systems including conventional proportional-integral-derivative controllers were designed employing the control strategy that uses a spray valve and two electric heaters for pressure control and regulates the charging flow rate with the letdown flow rate keeping constant for water level control. Finally, a simulation platform for the small pressurized water reactor pressurizer was developed in MATLAB/Simulink with implementation of the proposed nonlinear and nonequilibrium three-region pressurizer model, a widely-used nonlinear and nonequilibrium three-region pressurizer model and the designed pressure and water level controllers. Two typical load change transients, including the 100% to 90% of full power step load decrease and load rejection from 100% to 25% of full power, were simulated based on the platform. Dynamic responses of the pressure and water level obtained using the two nonlinear pressurizer models were analyzed, and the controller performances were assessed. The analysis and assessment results have shown satisfactory control performance and good robustness of the designed controllers regardless of the pressurizer simulation model adopted, demonstrating the feasibility, effectiveness and accuracy of the developed nonlinear and transfer function models of the pressurizer for dynamic simulation and controller design.
-
control simulation and study of load rejection transient for ap1000
Progress in Nuclear Energy, 2015Co-Authors: Pengfei Wang, Fuyu Zhao, Zhi Chen, Rui Zhang, Jian Sun, Xinyu WeiAbstract:Abstract The AP1000 nuclear steam supply system (NSSS) is designed to accept large load rejections without initiating a reactor trip using the reactor power control system, the pressurizer pressure and water level control systems, the feedwater control system, the steam dump control system and the rapid power reduction (RPR) system. This paper presents the dynamic simulation and study of load rejection transients for the AP1000 NSSS. A real-time NSSS simulation platform is developed in Matlab/Simulink environment with implementation of a nodal core model, a three-region non-equilibrium pressurizer model, a nonlinear steam generator model, a feedwater system model, a main steam system model, and the relevant control systems. Based on the simulation platform, three typical load rejection transients from full power (FP) are simulated, including the 50%FP load rejection without RPR, the large load rejection to 25%FP with RPR and the load rejection to house load. The simulation results show that the NSSS control systems can successfully respond to load rejection transients without reactor trip or operation of the pressurizer or steam generator safety valves. Sustained stable operation can be obtained under the condition of the minimum house load due to the proper control system responses. Science the world's first AP1000 plant is being constructed in China, these simulation and analysis results can make us have a better understanding of the load rejection operations and the special steam dump and RPR control systems for AP1000, and offer certain guidance for the engineering practice.
Pengfei Wang - One of the best experts on this subject based on the ideXlab platform.
-
A fuzzy-logic-based pressure setpoint modification method for pressurized water reactor pressurizers
Annals of Nuclear Energy, 2020Co-Authors: Pengfei Wang, Jiashuang Wan, Fuyu ZhaoAbstract:Abstract For pressurized water reactors, the pressurizer pressure is expected to be maintained constant to limit adverse impacts on the reactor due to pressure variations. To achieve this, a constant pressure setpoint is usually adopted in the pressurizer pressure control system. But it may not guarantee satisfactory pressure control performances especially under severe transient conditions. A feasible solution may be adjusting the pressure setpoint during transient processes and then restoring it to the initial value. For this purpose, the paper proposes a fuzzy-logic-based pressure setpoint modification (FPSM) method for pressurizers. A simulation platform was developed in MATLAB/Simulink implementing a nonequilibrium three-region pressurizer model, the pressure and waterlevel control systems and the FPSM system. Simulation studies of the AP1000 pressurizer during typical load change transients were performed, and responses of the pressurizer implementing the FPSM system are compared with those employing constant pressure setpoint to demonstrate feasibility and effectiveness of the system.
-
Mathematical modeling of a pressurizer in a pressurized water reactor for control design
Applied Mathematical Modelling, 2019Co-Authors: Pengfei Wang, Xinyu Wei, Fuyu ZhaoAbstract:Abstract A pressurizer is a key equipment to ensure the safe operation of a pressurized water reactor by maintaining the reactor coolant system pressure within allowed tolerances. In this paper, a nonequilibrium three-region pressurizer model for the pressurized water reactor was developed first base on the basic conservation laws of mass and energy for the steam and water in the pressurizer. Then the nonlinear model was linearized to introduce the transfer function models of the pressurizer during insurge and outsurge transients for the controller design of a small pressurized water reactor pressurizer. Based on the developed transfer function models, the closed-loop pressurizer pressure and water level control systems including conventional proportional-integral-derivative controllers were designed employing the control strategy that uses a spray valve and two electric heaters for pressure control and regulates the charging flow rate with the letdown flow rate keeping constant for water level control. Finally, a simulation platform for the small pressurized water reactor pressurizer was developed in MATLAB/Simulink with implementation of the proposed nonlinear and nonequilibrium three-region pressurizer model, a widely-used nonlinear and nonequilibrium three-region pressurizer model and the designed pressure and water level controllers. Two typical load change transients, including the 100% to 90% of full power step load decrease and load rejection from 100% to 25% of full power, were simulated based on the platform. Dynamic responses of the pressure and water level obtained using the two nonlinear pressurizer models were analyzed, and the controller performances were assessed. The analysis and assessment results have shown satisfactory control performance and good robustness of the designed controllers regardless of the pressurizer simulation model adopted, demonstrating the feasibility, effectiveness and accuracy of the developed nonlinear and transfer function models of the pressurizer for dynamic simulation and controller design.
-
control simulation and study of load rejection transient for ap1000
Progress in Nuclear Energy, 2015Co-Authors: Pengfei Wang, Fuyu Zhao, Zhi Chen, Rui Zhang, Jian Sun, Xinyu WeiAbstract:Abstract The AP1000 nuclear steam supply system (NSSS) is designed to accept large load rejections without initiating a reactor trip using the reactor power control system, the pressurizer pressure and water level control systems, the feedwater control system, the steam dump control system and the rapid power reduction (RPR) system. This paper presents the dynamic simulation and study of load rejection transients for the AP1000 NSSS. A real-time NSSS simulation platform is developed in Matlab/Simulink environment with implementation of a nodal core model, a three-region non-equilibrium pressurizer model, a nonlinear steam generator model, a feedwater system model, a main steam system model, and the relevant control systems. Based on the simulation platform, three typical load rejection transients from full power (FP) are simulated, including the 50%FP load rejection without RPR, the large load rejection to 25%FP with RPR and the load rejection to house load. The simulation results show that the NSSS control systems can successfully respond to load rejection transients without reactor trip or operation of the pressurizer or steam generator safety valves. Sustained stable operation can be obtained under the condition of the minimum house load due to the proper control system responses. Science the world's first AP1000 plant is being constructed in China, these simulation and analysis results can make us have a better understanding of the load rejection operations and the special steam dump and RPR control systems for AP1000, and offer certain guidance for the engineering practice.
F. Wadia - One of the best experts on this subject based on the ideXlab platform.
-
ACETABULAR CEMENT PRESSURISATION: AN IN-VITRO STUDY OF DIFFERENT DESIGNS OF ACETABULAR CEMENT PressuriserS
2008Co-Authors: F. Wadia, M. H. A Malik, J Leonard, M L PorterAbstract:A secure bone cement interface between the acetabulum and the cement mantle of the hip socket is an important requirement for the long-term success of a cemented hip arthroplasty. Cement pressurisation after bone bed cleaning enables cement to penetrate interstices of cancellous bone forming a superior fixation strength. We designed an in-vitro experiment to evaluate the performance of the Exeter, Depuy T-handle and a plunger-type Pressurisers using two parameters: cement penetration and cement pressurisation. The deformation of the flexible pressure head of the DePuy model produced a cement mantle, which is thick at the pole but tapered at its rim and variable in the amount of penetration produced (range 2–8mm) for an estimated similar force. Pressures of up to 60KPa were generated throughout the model acetabulum. The Exeter Pressuriser was found to produce cement mantles more compatible with a socket. However, the test results show a wide variation in cement penetration occurring for what was estimated to be a similar applied force (3mm to 9mm at the pole and 5mm to 9mm at the rim). It was also shown to have the disadvantage of causing widely dissimilar pressures at the pole and the rim. The plunger protrusion required to produce 5mm cement penetration was found to be 7.5mm. Since this protrusion can be monitored and controlled by the operator, a cement intrusion of 5mm +/−1mm was found to be reproducible with the plunger-type device. The maximum variation in intrusion between rim and pole was 1 mm. Maximin pressures of 70KPa were generated. We have presented experimental evidence that suggests that a plunger type of acetabular cement Pressuriser may provide a more consistently reproducible level of pressurisation leading to optimal cement penetration.
-
Cement pressurisation in the acetabulum
International Orthopaedics, 2006Co-Authors: F. Wadia, D Leonard, M. H. A Malik, M L PorterAbstract:La pressurisation du ciment est une étape importante dans la prothèse totale de hanche qui peut déterminer une bonne intégration, à long terme, des implants, notamment à l’interface ciment-os. Le but de notre étude est d’évaluer les performances d’un nouvel appareil destiné à Pressuriser le ciment, en comparaison avec l’appareil préexistant, cette comparaison étant réalisée au cours d’une étude expérimentale in vitro avec étude de deux paramètres, la pénétration et la pressurisation du ciment. Une cupule en polypropylène a été fabriquée comme modèle d’accétabulum. Nous avons ensuite mesuré la pénétration et la pressurisation du ciment, nous avons utilisé trois appareils, le porte cupule Depuy, l’appareil d’Exeter et notre propre appareillage. Résultats : l’intrusion du ciment dans les capillaires avec le porte cupule Depuy a été de 2 à 8 mm, avec l’appareil d’Exeter de 3 à 9 mm et avec notre nouvel appareillage de 4 à 6 mm. Le type de pression avec l’appareil porte cupule Depuy a été de 60 kPa alors qu’il était de 70 kPa avec notre nouvel appareillage. En conclusion : la pénétration moyenne avec notre nouvel appareillage a été nettement améliorée si on la compare aux autres types d’appareillage. Cette pénétration a été plus uniforme que se soit au pourtour de la cupule ou au niveau des pôles. Cement pressurisation is an important step in total hip arthroplasty that determines the long-term integration at the cement-bone interface. Our aim was to evaluate the performance of a new Pressuriser designed by us against the standard existing Pressurisers in an in vitro experimental set-up using two parameters: cement penetration and cement pressurisation. A polypropylene cup model was designed to represent the acetabulum. DePuy’s T-handle, Exeter and our own plunger type Pressuriser were each tested for cement pressurisation in this acetabular model. Cement penetration and pressures were measured. The cement intrusion into the capillaries with the DePuy Pressuriser was found to vary between 2 and 8 mm (mean: 5 mm at the pole and 4.6 mm at the rim), with the Exeter Pressuriser it varied between 3 and 9 mm (mean: 5.8 mm at the pole and 7.8 mm at the rim) and with the plunger type Pressuriser it varied between 4 and 6 mm (mean 5.2 mm at the pole and 4.8 mm at the rim). The peak pressure achieved with the DePuy Pressuriser was 60 kPa whereas it was 70 kPa with the plunger type Pressuriser. The mean penetration with the plunger type Pressuriser was found to be better than the other types. The penetration was found to be more uniform with equal penetration at the rim as well as at the pole.
-
Cement pressurisation in the acetabulum.
International orthopaedics, 2006Co-Authors: F. Wadia, D Leonard, Mohammad Azad Malik, M L PorterAbstract:Cement pressurisation is an important step in total hip arthroplasty that determines the long-term integration at the cement-bone interface. Our aim was to evaluate the performance of a new Pressuriser designed by us against the standard existing Pressurisers in an in vitro experimental set-up using two parameters: cement penetration and cement pressurisation. A polypropylene cup model was designed to represent the acetabulum. DePuy’s T-handle, Exeter and our own plunger type Pressuriser were each tested for cement pressurisation in this acetabular model. Cement penetration and pressures were measured. The cement intrusion into the capillaries with the DePuy Pressuriser was found to vary between 2 and 8 mm (mean: 5 mm at the pole and 4.6 mm at the rim), with the Exeter Pressuriser it varied between 3 and 9 mm (mean: 5.8 mm at the pole and 7.8 mm at the rim) and with the plunger type Pressuriser it varied between 4 and 6 mm (mean 5.2 mm at the pole and 4.8 mm at the rim). The peak pressure achieved with the DePuy Pressuriser was 60 kPa whereas it was 70 kPa with the plunger type Pressuriser. The mean penetration with the plunger type Pressuriser was found to be better than the other types. The penetration was found to be more uniform with equal penetration at the rim as well as at the pole.
Wen Chen - One of the best experts on this subject based on the ideXlab platform.
-
research on pressurizer water level control of pressurized water reactor nuclear power station
Energy Procedia, 2012Co-Authors: Guo Duo Zhang, Xu Hong Yang, Wen ChenAbstract:Abstract In this paper, the subject is the water level control of the pressurizer in nuclear power plant. The water level of pressurizer dynamics testing and analysis, calculating the transfer function, as well as comparing the design of PID controller and fuzzy controller are all completed. At last, in order to get better control of the water level of the pressurizer, a fuzzy PID controller is designed and it has good control effect.