The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform

Yukihide Iwamoto - One of the best experts on this subject based on the ideXlab platform.

  • Alignment in total knee arthroplasty following failed high tibial osteotomy.
    Journal of Knee Surgery, 2003
    Co-Authors: Tsutomu Kawano, Ryuji Nagamine, Shuichi Matsuda, Hiromasa Miura, Ken Urabe, Taro Mawatari, Takaaki Moro-oka, Yukihide Iwamoto
    Abstract:

    : In total knee arthroplasty (TKA) following failed high tibial osteotomy, the mechanical Axis does not intersect the center of the tibial component if the tibia has been resected perpendicular to the anatomical Axis. Therefore, tibial resection referencing the predicted postoperative mechanical Axis instead of the tibial Shaft Axis is advocated. To obtain the optimal tibial resection, characteristics of the tibial proximal deformity were measured radiographically and predicted postoperative lower limb alignment was calculated using full-length, weight-bearing, lower limb anteroposterior radiographs. Two finite element analysis models also were examined. The proximal tibia was resected perpendicular to the tibial Shaft Axis in model 1, and perpendicular to the predicted postoperative tibial mechanical Axis in model 2. When the proximal tibia was resected perpendicular to the tibial Shaft Axis, the predicted lower limb mechanical Axis was significantly shifted medially to the center of the tibial joint surface. The results of the finite element analysis reflected the medial shift of the lower limb mechanical Axis in model 1, where stresses were increased in the medial tibial compartment. Tibial resection referencing the predicted postoperative tibial mechanical Axis, instead of the tibial Shaft Axis, should be performed, especially in cases with a deformed tibia.

  • Tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Hideki Mizu-uchi, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P

  • tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Hideki Mizuuchi, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P<.0001). The postoperative weight-bearing ratio was in Method 1, 57.7%, in Method 2, 53.6% and 50.0% in Method 3. These results suggest that cutting the tibia perpendicular to the tibial Shaft can cause valgus alignment in total knee arthroplasty for varus knees. Copyright 2003, Elsevier Science (USA). All rights reserved.

Yoshinori Ando - One of the best experts on this subject based on the ideXlab platform.

  • High temperature superconducting levitation flywheel system and its control
    Journal of Materials Processing Technology, 2020
    Co-Authors: Kosuke Nagaya, Kazuya Kobayashi, Masato Saito, Yoshinori Ando
    Abstract:

    Abstract A simple and stable flywheel system with high temperature superconducting levitation is presented, in which a control is not needed for levitation. In order to have stable levitation, a superconductor and a permanent magnet are used, and three permanent magnets support the top of the Shaft. In the part of drive system, eight-poles cylindrical permanent magnet and eight cylindrical coils are used to drive the rotor, in which magnetic forces in the direction perpendicular to the Shaft Axis are cancelled. Hence, vibration force due to the driving is zero in this system. A coil-type electromagnetic damper is presented which works in the magnetic field of levitation permanent magnet. It consists of four coils. The dampers lie at both ends of the Shaft. When the Shaft vibrates in the direction perpendicular to the Shaft Axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the Shaft when the velocity feedback is performed, so that the force behaves like damping forces. Using this system, a control like the sensor less control can be performed by using sensors consisting of coils only. Analytical expressions are obtained for the torque for our cylindrical-type motor, and a method for accelerating the Shaft is presented by controlling the voltage of the coil based on the expressions. Experimental tests have been carried out. It is clarified that our system has stable levitation, and vibrations are extremely suppressed.

  • High temperature superconducting levitation flywheel system and its control
    Journal of Materials Processing Technology, 2007
    Co-Authors: Kosuke Nagaya, Kazuya Kobayashi, Masato Saito, Yoshinori Ando
    Abstract:

    A simple and stable flywheel system with high temperature superconducting levitation is presented, in which a control is not needed for levitation. In order to have stable levitation, a superconductor and a permanent magnet are used, and three permanent magnets support the top of the Shaft. In the part of drive system, eight-poles cylindrical permanent magnet and eight cylindrical coils are used to drive the rotor, in which magnetic forces in the direction perpendicular to the Shaft Axis are cancelled. Hence, vibration force due to the driving is zero in this system. A coil-type electromagnetic damper is presented which works in the magnetic field of levitation permanent magnet. It consists of four coils. The dampers lie at both ends of the Shaft. When the Shaft vibrates in the direction perpendicular to the Shaft Axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the Shaft when the velocity feedback is performed, so that the force behaves like damping forces. Using this system, a control like the sensor less control can be performed by using sensors consisting of coils only. Analytical expressions are obtained for the torque for our cylindrical-type motor, and a method for accelerating the Shaft is presented by controlling the voltage of the coil based on the expressions. Experimental tests have been carried out. It is clarified that our system has stable levitation, and vibrations are extremely suppressed. ?? 2006 Elsevier B.V. All rights reserved.

Kosuke Nagaya - One of the best experts on this subject based on the ideXlab platform.

  • High temperature superconducting levitation flywheel system and its control
    Journal of Materials Processing Technology, 2020
    Co-Authors: Kosuke Nagaya, Kazuya Kobayashi, Masato Saito, Yoshinori Ando
    Abstract:

    Abstract A simple and stable flywheel system with high temperature superconducting levitation is presented, in which a control is not needed for levitation. In order to have stable levitation, a superconductor and a permanent magnet are used, and three permanent magnets support the top of the Shaft. In the part of drive system, eight-poles cylindrical permanent magnet and eight cylindrical coils are used to drive the rotor, in which magnetic forces in the direction perpendicular to the Shaft Axis are cancelled. Hence, vibration force due to the driving is zero in this system. A coil-type electromagnetic damper is presented which works in the magnetic field of levitation permanent magnet. It consists of four coils. The dampers lie at both ends of the Shaft. When the Shaft vibrates in the direction perpendicular to the Shaft Axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the Shaft when the velocity feedback is performed, so that the force behaves like damping forces. Using this system, a control like the sensor less control can be performed by using sensors consisting of coils only. Analytical expressions are obtained for the torque for our cylindrical-type motor, and a method for accelerating the Shaft is presented by controlling the voltage of the coil based on the expressions. Experimental tests have been carried out. It is clarified that our system has stable levitation, and vibrations are extremely suppressed.

  • Vibration suppression for high temperature superconducting levitation flywheel system using coil dampers
    International Journal of Applied Electromagnetics and Mechanics, 2007
    Co-Authors: Kosuke Nagaya, Kazuya Kobayashi, Masato Saito, Iwanori Murakami
    Abstract:

    A simple and stable flywheel system with high temperature superconducting levitation is presented that needs no control for levitation. The drive system consists of eight-poles cylindrical permanent magnet and eight cylindrical coils, in which magnetic forces in the direction perpendicular to the Shaft Axis are cancelled. Hence, vibration force due to the driving is zero in this system. A coil-type electromagnetic damper is also presented which works in the magnetic field of levitation permanent magnet. The dampers lie at both ends of the Shaft. Using this system, a control like the sensorless control can be performed by using coils only. The control method has been presented and analytical expressions are also obtained for vibrations of the Shaft. To validate the analysis, experimental tests have been carried out.

  • High temperature superconducting levitation flywheel system and its control
    Journal of Materials Processing Technology, 2007
    Co-Authors: Kosuke Nagaya, Kazuya Kobayashi, Masato Saito, Yoshinori Ando
    Abstract:

    A simple and stable flywheel system with high temperature superconducting levitation is presented, in which a control is not needed for levitation. In order to have stable levitation, a superconductor and a permanent magnet are used, and three permanent magnets support the top of the Shaft. In the part of drive system, eight-poles cylindrical permanent magnet and eight cylindrical coils are used to drive the rotor, in which magnetic forces in the direction perpendicular to the Shaft Axis are cancelled. Hence, vibration force due to the driving is zero in this system. A coil-type electromagnetic damper is presented which works in the magnetic field of levitation permanent magnet. It consists of four coils. The dampers lie at both ends of the Shaft. When the Shaft vibrates in the direction perpendicular to the Shaft Axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the Shaft when the velocity feedback is performed, so that the force behaves like damping forces. Using this system, a control like the sensor less control can be performed by using sensors consisting of coils only. Analytical expressions are obtained for the torque for our cylindrical-type motor, and a method for accelerating the Shaft is presented by controlling the voltage of the coil based on the expressions. Experimental tests have been carried out. It is clarified that our system has stable levitation, and vibrations are extremely suppressed. ?? 2006 Elsevier B.V. All rights reserved.

Shuichi Matsuda - One of the best experts on this subject based on the ideXlab platform.

  • Alignment in total knee arthroplasty following failed high tibial osteotomy.
    Journal of Knee Surgery, 2003
    Co-Authors: Tsutomu Kawano, Ryuji Nagamine, Shuichi Matsuda, Hiromasa Miura, Ken Urabe, Taro Mawatari, Takaaki Moro-oka, Yukihide Iwamoto
    Abstract:

    : In total knee arthroplasty (TKA) following failed high tibial osteotomy, the mechanical Axis does not intersect the center of the tibial component if the tibia has been resected perpendicular to the anatomical Axis. Therefore, tibial resection referencing the predicted postoperative mechanical Axis instead of the tibial Shaft Axis is advocated. To obtain the optimal tibial resection, characteristics of the tibial proximal deformity were measured radiographically and predicted postoperative lower limb alignment was calculated using full-length, weight-bearing, lower limb anteroposterior radiographs. Two finite element analysis models also were examined. The proximal tibia was resected perpendicular to the tibial Shaft Axis in model 1, and perpendicular to the predicted postoperative tibial mechanical Axis in model 2. When the proximal tibia was resected perpendicular to the tibial Shaft Axis, the predicted lower limb mechanical Axis was significantly shifted medially to the center of the tibial joint surface. The results of the finite element analysis reflected the medial shift of the lower limb mechanical Axis in model 1, where stresses were increased in the medial tibial compartment. Tibial resection referencing the predicted postoperative tibial mechanical Axis, instead of the tibial Shaft Axis, should be performed, especially in cases with a deformed tibia.

  • Tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Hideki Mizu-uchi, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P

  • tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Hideki Mizuuchi, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P<.0001). The postoperative weight-bearing ratio was in Method 1, 57.7%, in Method 2, 53.6% and 50.0% in Method 3. These results suggest that cutting the tibia perpendicular to the tibial Shaft can cause valgus alignment in total knee arthroplasty for varus knees. Copyright 2003, Elsevier Science (USA). All rights reserved.

Hiromasa Miura - One of the best experts on this subject based on the ideXlab platform.

  • Alignment in total knee arthroplasty following failed high tibial osteotomy.
    Journal of Knee Surgery, 2003
    Co-Authors: Tsutomu Kawano, Ryuji Nagamine, Shuichi Matsuda, Hiromasa Miura, Ken Urabe, Taro Mawatari, Takaaki Moro-oka, Yukihide Iwamoto
    Abstract:

    : In total knee arthroplasty (TKA) following failed high tibial osteotomy, the mechanical Axis does not intersect the center of the tibial component if the tibia has been resected perpendicular to the anatomical Axis. Therefore, tibial resection referencing the predicted postoperative mechanical Axis instead of the tibial Shaft Axis is advocated. To obtain the optimal tibial resection, characteristics of the tibial proximal deformity were measured radiographically and predicted postoperative lower limb alignment was calculated using full-length, weight-bearing, lower limb anteroposterior radiographs. Two finite element analysis models also were examined. The proximal tibia was resected perpendicular to the tibial Shaft Axis in model 1, and perpendicular to the predicted postoperative tibial mechanical Axis in model 2. When the proximal tibia was resected perpendicular to the tibial Shaft Axis, the predicted lower limb mechanical Axis was significantly shifted medially to the center of the tibial joint surface. The results of the finite element analysis reflected the medial shift of the lower limb mechanical Axis in model 1, where stresses were increased in the medial tibial compartment. Tibial resection referencing the predicted postoperative tibial mechanical Axis, instead of the tibial Shaft Axis, should be performed, especially in cases with a deformed tibia.

  • Tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Hideki Mizu-uchi, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P

  • tibial Shaft Axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees
    Journal of Arthroplasty, 2003
    Co-Authors: Shuichi Matsuda, Ryuji Nagamine, Hiromasa Miura, Ken Urabe, Hideki Mizuuchi, Yukihide Iwamoto
    Abstract:

    Predicted postoperative knee alignment was calculated when total knee arthroplasty was performed after 1 of 3 different methods of tibia preparation in 30 osteoarthritic knees with varus deformity. In Method 1, the tibia was cut perpendicular to the tibial Shaft. In Method 2, the tibia was cut perpendicular to a line connecting the center of the tibial plateau and the center of the talar dome. In method 3, tibial resection was determined with an original template so that tibial resection would be perpendicular to a line connecting the center of the resected tibial plateau and the center of the talar dome. Methods 1 and 2 caused significantly more valgus alignment than Method 3 (P<.0001). The postoperative weight-bearing ratio was in Method 1, 57.7%, in Method 2, 53.6% and 50.0% in Method 3. These results suggest that cutting the tibia perpendicular to the tibial Shaft can cause valgus alignment in total knee arthroplasty for varus knees. Copyright 2003, Elsevier Science (USA). All rights reserved.