The Experts below are selected from a list of 32448 Experts worldwide ranked by ideXlab platform

Peter Omand Rasmussen - One of the best experts on this subject based on the ideXlab platform.

  • Theoretical and Experimental Loss and Efficiency Studies of a Magnetic Lead Screw
    IEEE Transactions on Industry Applications, 2015
    Co-Authors: Nick Ilsoe Berg, Rasmus Koldborg Holm, Peter Omand Rasmussen
    Abstract:

    This paper investigates mechanical and magnetic losses in a magnetic lead screw (MLS). The MLS converts a low-speed high-force Linear motion of a translator into a high-speed low-torque rotational motion of a rotor through helically shaped magnets. Initial tests performed with a novel 17-kN demonstrator and a simplified motor model showed an efficiency of only 80% at low load; however, it was expected that the efficiency should be above 95%. For understanding and future optimization, a detailed study of the loss in the MLS is presented with the aim of identifying and segregating various loss components that was not accounted for in previous results. This is done through theoretical loss calculations and various experiments. It is concluded that the Linear Guide is the dominating loss component in the MLS demonstrator, whereas the losses in the axial thrust bearing is not as dominant as expected; furthermore, an efficiency above 94% was measured.

  • Theoretical and experimental loss and efficiency studies of a magnetic lead screw
    2013 IEEE Energy Conversion Congress and Exposition, 2013
    Co-Authors: Nick Ilsoe Berg, Rasmus Koldborg Holm, Peter Omand Rasmussen
    Abstract:

    This paper investigates mechanical and magnetic losses in a magnetic lead screw (MLS). The MLS converts a low speed high force Linear motion of a translator into a high speed low torque rotational motion of a rotor through helically shaped magnets. Initial tests performed with a novel 17 kN demonstrator and a simplified motor model showed an efficiency of only 80 % at low load, however it was expected that the efficiency should be above 95 %. For understanding and future optimization a detailed study of the loss in the MLS is presented with the aim of identifying and segregate various loss components which was not accounted for in previously results. This is done through theoretical loss calculations and various experiments. It is concluded that the Linear Guide is the dominating loss component in the MLS demonstrator, while the losses in the axial thrust bearing is not as dominant as expected, further an efficiency above 94 % was measured.

Wada Kenji - One of the best experts on this subject based on the ideXlab platform.

  • Development of two directional beam steering ECH/CD launcher for JT-60SA
    'Elsevier BV', 2019
    Co-Authors: Kobayashi Takayuki, Kajiwara Ken, Oda Yasuhisa, Ikeda Ryosuke, Isayama Akihiko, Hiranai Shinichi, Sawahata Masayuki, Terakado Masayuki, Sato Fumiaki, Wada Kenji
    Abstract:

    Developments of a two directional beam steering electron cyclotron heating/current drive launcher for JT-60SA have been progressed based on a Linear motion antenna concept. A full-scale (˜7 m) mock-up of the mirror steering structure with two kinds of bellows structures and an in-vessel support structure has been fabricated and tested in vacuum successfully. The support structure consists of a pair of angular ball bearings made of Si3N4 for rotational motion and a Linear Guide assembled by a rail and a housing made of non-magnetic stainless steel and Si3N4 balls. Solid lubricant has been used for the Linear Guide and it results in the improvement of the life time by a factor greater than 10 with respect to the case without lubricant. Considering that the mock-up test results satisfied the requirements for the bellows and support structures (reliable 40 cm Linear movement, 105 cycles and angular rotation 30°, 104 cycles), the final design of the launcher is underway targeting the start of its fabrication

  • Development of two directional beam steering ECH/CD launcher for JT-60SA
    2019
    Co-Authors: Kobayashi Takayuki, Kajiwara Ken, Oda Yasuhisa, Ikeda Ryosuke, Isayama Akihiko, Hiranai Shinichi, Sawahata Masayuki, Terakado Masayuki, Sato Fumiaki, Wada Kenji
    Abstract:

    Developments of a two directional beam steering electron cyclotron heating/current drive launcher for JT-60SA have been progressed based on a Linear motion antenna concept. A full-scale (~7m) mock-up of the mirror steering structure with two kinds of bellows structures and an in-vessel support structure has been fabricated and tested in vacuum successfully. The support structure consists of a pair of angular ball bearings made of Si3N4 for rotational motion and a Linear Guide assembled by a rail and a housing made of non-magnetic stainless steel and Si3N4 balls. Solid lubricant has been used for the Linear Guide and it results in the improvement of the life time by a factor of greater than 10 with respect to the case without lubricant. Considering that the mock-up test results satisfied the requirements for the bellows and support structures (reliable 40 cm Linear movement, 105 cycles and angular rotation 30°, 104 cycles), the final design of the launcher is underway targeting the start of its fabrication.30th Symposium on Fusion Technology (SOFT 2018

Lenarz Thomas - One of the best experts on this subject based on the ideXlab platform.

  • Minimally invasive mastoidectomy approach using a mouldable surgical targeting system: a proof of concept
    'Walter de Gruyter GmbH', 2018
    Co-Authors: Rau, Thomas S., Witte Sina, Uhlenbusch Lea, Lexow G. Jakob, Hügl Silke, Kahrs, Lüder A., Majdani Omid, Lenarz Thomas
    Abstract:

    Hearing restoration using a cochlear implant requires a surgical access to the inner ear. In order to enhance patient safety, reduce trauma, and shorten the patient’s time under anaesthesia current research focusses on minimally invasive cochlear implantation surgery by drilling only a single bore hole. This demands a highly accurate surgical assistance device to Guide the drill along a predetermined trajectory planned in patient’s image data. In this study a recently developed surgical targeting system was evaluated for the first time in a human cadaver trial. After screwing a reference frame on a temporal bone specimen and imaging of both, a trajectory through the facial recess was planned in order to reach the middle ear. Based on this plan a patient specific surgical template including a Linear Guide for the surgical drill was composed utilizing bone cement. After the hardening of the bone cement the surgical template was mounted on top of the reference frame. The drilling could be performed as previously planned without harming facial nerve and chorda tympani. The deviation of the actual drill hole to the planned trajectory was 0.17 mm at the level of the facial recess. The minimal distance of the drill hole to the facial nerve was 0.59 mm. This proof-of-concept study demonstrates the feasibility of performing the access to the middle ear in a minimally invasive manner using the mouldable surgical targeting system. The presented process allows the patient specific individualization of a drill Guide under sterile conditions. This might facilitate its integration into clinical routine

  • Minimally invasive mastoidectomy approach using a mouldable surgical targeting system. A proof of concept
    Berlin : Walter de Gruyter, 2018
    Co-Authors: Rau, Thomas S., Witte Sina, Uhlenbusch Lea, Hügl Silke, Kahrs, Lüder A., Majdani Omid, Lexow Jakob, Lenarz Thomas
    Abstract:

    Hearing restoration using a cochlear implant requires a surgical access to the inner ear. In order to enhance patient safety, reduce trauma, and shorten the patient's time under anaesthesia current research focusses on minimally invasive cochlear implantation surgery by drilling only a single bore hole. This demands a highly accurate surgical assistance device to Guide the drill along a predetermined trajectory planned in patient's image data. In this study a recently developed surgical targeting system was evaluated for the first time in a human cadaver trial. After screwing a reference frame on a temporal bone specimen and imaging of both, a trajectory through the facial recess was planned in order to reach the middle ear. Based on this plan a patient specific surgical template including a Linear Guide for the surgical drill was composed utilizing bone cement. After the hardening of the bone cement the surgical template was mounted on top of the reference frame. The drilling could be performed as previously planned without harming facial nerve and chorda tympani. The deviation of the actual drill hole to the planned trajectory was 0.17 mm at the level of the facial recess. The minimal distance of the drill hole to the facial nerve was 0.59 mm. This proof-of-concept study demonstrates the feasibility of performing the access to the middle ear in a minimally invasive manner using the mouldable surgical targeting system. The presented process allows the patient specific individualization of a drill Guide under sterile conditions. This might facilitate its integration into clinical routine. © 2018 Thomas S. Rau et al

  • Minimally invasive mastoidectomy approach using a mouldable surgical targeting system
    'Walter de Gruyter GmbH', 2018
    Co-Authors: Rau, Thomas S., Witte Sina, Uhlenbusch Lea, Hügl Silke, Majdani Omid, Lexow Jakob, Lenarz Thomas
    Abstract:

    Hearing restoration using a cochlear implant requires a surgical access to the inner ear. In order to enhance patient safety, reduce trauma, and shorten the patient’s time under anaesthesia current research focusses on minimally invasive cochlear implantation surgery by drilling only a single bore hole. This demands a highly accurate surgical assistance device to Guide the drill along a predetermined trajectory planned in patient’s image data. In this study a recently developed surgical targeting system was evaluated for the first time in a human cadaver trial. After screwing a reference frame on a temporal bone specimen and imaging of both, a trajectory through the facial recess was planned in order to reach the middle ear. Based on this plan a patient specific surgical template including a Linear Guide for the surgical drill was composed utilizing bone cement. After the hardening of the bone cement the surgical template was mounted on top of the reference frame. The drilling could be performed as previously planned without harming facial nerve and chorda tympani. The deviation of the actual drill hole to the planned trajectory was 0.17 mm at the level of the facial recess. The minimal distance of the drill hole to the facial nerve was 0.59 mm. This proof-of-concept study demonstrates the feasibility of performing the access to the middle ear in a minimally invasive manner using the mouldable surgical targeting system. The presented process allows the patient specific individualization of a drill Guide under sterile conditions. This might facilitate its integration into clinical routine

Nick Ilsoe Berg - One of the best experts on this subject based on the ideXlab platform.

  • Theoretical and Experimental Loss and Efficiency Studies of a Magnetic Lead Screw
    IEEE Transactions on Industry Applications, 2015
    Co-Authors: Nick Ilsoe Berg, Rasmus Koldborg Holm, Peter Omand Rasmussen
    Abstract:

    This paper investigates mechanical and magnetic losses in a magnetic lead screw (MLS). The MLS converts a low-speed high-force Linear motion of a translator into a high-speed low-torque rotational motion of a rotor through helically shaped magnets. Initial tests performed with a novel 17-kN demonstrator and a simplified motor model showed an efficiency of only 80% at low load; however, it was expected that the efficiency should be above 95%. For understanding and future optimization, a detailed study of the loss in the MLS is presented with the aim of identifying and segregating various loss components that was not accounted for in previous results. This is done through theoretical loss calculations and various experiments. It is concluded that the Linear Guide is the dominating loss component in the MLS demonstrator, whereas the losses in the axial thrust bearing is not as dominant as expected; furthermore, an efficiency above 94% was measured.

  • Theoretical and experimental loss and efficiency studies of a magnetic lead screw
    2013 IEEE Energy Conversion Congress and Exposition, 2013
    Co-Authors: Nick Ilsoe Berg, Rasmus Koldborg Holm, Peter Omand Rasmussen
    Abstract:

    This paper investigates mechanical and magnetic losses in a magnetic lead screw (MLS). The MLS converts a low speed high force Linear motion of a translator into a high speed low torque rotational motion of a rotor through helically shaped magnets. Initial tests performed with a novel 17 kN demonstrator and a simplified motor model showed an efficiency of only 80 % at low load, however it was expected that the efficiency should be above 95 %. For understanding and future optimization a detailed study of the loss in the MLS is presented with the aim of identifying and segregate various loss components which was not accounted for in previously results. This is done through theoretical loss calculations and various experiments. It is concluded that the Linear Guide is the dominating loss component in the MLS demonstrator, while the losses in the axial thrust bearing is not as dominant as expected, further an efficiency above 94 % was measured.

Chingyuan Lin - One of the best experts on this subject based on the ideXlab platform.

  • fault detection of Linear Guide preload of a positioning stage with vibration acoustic analysis
    Journal of Failure Analysis and Prevention, 2011
    Co-Authors: Juipin Hung, Chingyuan Lin, Tzuoliang Luo
    Abstract:

    The vibration analysis method has been widely used to detect faults in the components of a machine. For a Linear positioning stage, its vibration characteristics are closely related to and affected by the preload of Linear Guides. To clarify the meaning of the vibration signals coming out from an abnormal machine, in this study we aimed to investigate the influence of a faulty Linear Guide on the vibration and acoustic characteristics of a positioning stage through experimental and finite element modeling approaches. Experimental measurements indicate that stages equipped with abnormal or damaged Linear Guides indeed exhibit different vibration behavior compared to stages with intact Guides. According to finite element analysis, the variation in vibration characteristics can be attributed to the changes in the structural stiffness of Linear Guides because of rolling ball defects. This phenomenon was also found in the acoustic characteristics measured for stages under various preloaded conditions, providing further correlations between the variations in acoustic characteristics and changes in structural stiffness. The present results clearly show that faulty conditions of Linear Guides can be effectively detected by means of monitoring the vibration and acoustic characteristics of the stage.

  • modeling the machining stability of a vertical milling machine under the influence of the preloaded Linear Guide
    International Journal of Machine Tools & Manufacture, 2011
    Co-Authors: Juipin Hung, Yuanlung Lai, Chingyuan Lin
    Abstract:

    The prediction of machining stability is of great importance for the design of a machine tool capable of high-precision and high-speed machining. The machining performance is determined by the frequency characteristics of the machine tool structure and the dynamics of the cutting process, and can be expressed in terms of a stability lobe diagram. The aim of this study is to develop a finite element model to evaluate the dynamic characteristics and machining stability of a vertical milling system. Rolling interfaces with a contact stiffness defined by Hertz theory were used to couple the Linear components and the machine structures in the finite element model. Using the model, the vibration mode that had a dominant influence on the dynamic stiffness and the machining stability was determined. The results of the finite element simulations reveal that Linear Guides with different preloads greatly affect the dynamic behavior and milling stability of the vertical column spindle head system. These results were validated by performing vibration and machining tests. We conclude that the proposed model can be used to accurately evaluate the dynamic performance of machine tool systems designed with various configurations and with different Linear rolling components.