• Title/Summary/Keyword: disc

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Coupled temperature-displacement modeling to study the thermo-elastic instability in disc brakes

  • Ramkumar, E.;Mayuram, M.M.
    • Coupled systems mechanics
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    • v.1 no.2
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    • pp.165-182
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    • 2012
  • Macroscopic hot spots formed due to the large thermal gradients at the surface of the disc brake rotor, make the rotor to fail or wear out early. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature making the disc susceptible to hot spot formation. The formation of one hot spot event will predispose the system to future hot spotting at the same location. This leads to the complete thermo-elastic instability in the disc brakes; multitude parameters are responsible for the thermo elastic instability. The predominant factor is the sliding velocity and above a certain sliding velocity the instability of the brake system occurs and hot spots is formed in the surface of the disc brake. Commercial finite element package ABAQUS(R) is used to find the temperature distribution and the result is validated using Rowson's analytical model. A coupled analysis methodology is evolved for the automotive disc brake from the transient thermo-elastic contact analysis. Temperature variation is studied under different sliding speeds within the operation range.

Prediction of Load-displacement of the Disc Spring with the Friction (마찰을 고려한 접시 스프링의 하중 변위 곡선 예측)

  • Shin, Dong-Ho;Lee, Jung-Youn;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.4
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    • pp.344-351
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    • 2012
  • A disc spring consists of a conical disc. A load-displacement formula was newly developed in the form of energy method to consider both rigid and friction. The cross section of the disc spring has identical slope angles at the bottom of conical. To solve such a problem, an energy method calculation is proposed. To achieve the goal of this study, the proposed calculation is extended to a disc spring with friction. A firm basis background study based on Almen's work is presented in developing a new numerical approach to predict the available formulation for a disc spring with friction.

Mini-partial lateral corpectomy and hemilaminectomy for the treatment of heavily protruded thoracolumbar intervertebral disc in small dogs

  • Han, Hyun-Jung;Yoon, Hun-Young
    • Korean Journal of Veterinary Research
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    • v.59 no.4
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    • pp.213-217
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    • 2019
  • Five paraplegic dogs were diagnosed with thoracolumbar intervertebral disc disease with more than 50% compression of spinal cord. Because the lesions were determined to be disc extrusion on magnetic resonance imaging, a hemilaminectomy was initially performed, however, protruded discs were confirmed during surgery. To remove the protruded disc, modified partial lateral corpectomy (mini-PLC) was additionally performed. All dogs recovered to full ambulation within a median of 44 days without temporary deterioration or vertebral instability. Mini-PLC as described here enables successful removal of the protruded disc, while preserving vertebral stability in dogs for whom the use of hemilaminectomy is inevitable.

Deformation Analysis and Experimental Verification of DVD Optical Disc Holders (DVD 광 디스크 홀더의 변형 해석 및 실험적 검증)

  • 김진곤;박용국
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.5
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    • pp.164-170
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    • 2003
  • To ensure the reliability of DVDR-P and DVD-ROM, it is imperative to remedy the unrecoverable creep deformation and/or relaxation of the holding force of an optical disc holder. To predict the deformation of an optical disc holder, a deformation analysis of an 80 mm optical disc holder considering the creep characteristics of 3 plastic materials has been conducted. Subsequently, the results by this Finite Element Analysis (FEA) are experimentally verified. A disc holder inserted in a cartridge case is kept in a chamber of $60^{\circ}C$ with 90 % humidity for 24 hours. The arm span and the holding force of the disc holder are measured after being left for another 24 successive hours at a room temperature and under normal humidity. The predicted results by FEA are in good agreement with experimentally measured values.

Brown Sequard Syndrome Resulting from Cervical Disc Herniation Treated by Anterior Foraminotomy

  • Kim, Yeon-Seong;Lee, Jung-Kil;Joo, Sung-Pil;Kim, Soo-Han
    • Journal of Korean Neurosurgical Society
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    • v.38 no.2
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    • pp.136-140
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    • 2005
  • The authors describe two cases of Brown-Sequard syndrome associated with cervical disc herniation. In both cases, magnetic resonance images of the cervical spine showed a large paramedian disc herniation at C5-C6 with ipsilateral severe spinal cord compression. Microsurgical removal of the herniated disc via anterior foraminotomy was performed and complete decompression of the spinal cord was achieved. Postoperatively, the neurological symptoms recovered rapidly and both patients experienced a complete remission of their symptoms. Although Brown-Sequard syndrome is rarely associated with degenerative cervical spine disease, cervical disc herniation should be kept in mind and prompt evaluations are mandatory. To the best of our knowledge, these are the first reported case of Brown-Sequard syndrome produced by cervical disc herniation which was treated by anterior foraminotomy.

Structural Design of a Circumferential Friction Disc-brake, Considering Thermoelastic Instability (열탄성 불안정성을 고려한 원주면 마찰형 디스크 브레이크의 구조설계)

  • Song, Byoung-Cheol;Kang, Dong-Heon;Kim, Young-Hee;Park, Young-Chul;Lee, Kwon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.38-46
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    • 2007
  • Weight reduction for an automobile component has been sought to achieve fuel efficiency and energy conservation. In response to this trend, a new disc-brake called the circumferential friction disc-brake is suggested. This paper compares the mechanical performances of a conventional disc-brake and a suggested disc-brake, under the dynamic braking condition. The thermoelastic instability is considered to simulate the test condition. Furthermore, the metamodel using kriging interpolation method is introduced to obtain the optimum design of a suggested circumferential friction disc-brake. The design results obtained by the kriging method are compared with those obtained by the ANSYS.

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Two Cases on Tortipelvis caused by Lumbar Disc Herniation - Using Mckenzie Method Treatment (요추 추간판 탈출증에 의한 골반경사 치험 2례 - Mckenzie 수기요법을 이용)

  • Hwang, Hyung-Joo;Heo, Kwang-Ho;Keum, Dong-Ho
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.2 no.1
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    • pp.85-97
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    • 2007
  • Objectives : We evaluated the effect of Mckenzie method treatment by participating two patients suffering from Tortipelvis by lumbar disc herniation. Methods : Two patients were diagnosed as Tortipelvis by lumbar disc herniation through CT scan and X-ray examination. We used Mckenzie method and measured VAS(Visual analogue scale). Results and Conclusions : After using Mckenzie method treatment, We found out a recovery from both patients suffering from Tortipelvis by lumbar disc herniation. The result, through our study, suggests that Mckenzie method treatment was effective to cure the Tortipelvis by lumbar disc herniation. It also was effective to reduce the low back pain and to stabilize the lumbar disc herniation.

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Vibration Reduction of an Optical Disc Drive by Using Dynamic Vibration Absorber (동흡진기를 이용한 광디스크 드라이브의 진동저감)

  • 박준민;허진욱;이영원;서영선;정진태
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.706-711
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    • 2001
  • A dynamic vibration absorber(DVA) is developed to reduce the excessive focusing vibration of an optical disc drive(ODD) originated from the resonance of an wobble disc. We design the material properties of the DVA by FEM model such as Young's modules, damping coefficient, shapes and dimensions, analyze its dynamic characteristics and provide its design guide line for suppressing the vibration of an optical disc drive. To examine the performance. of the DVA, the vibration of the wobble disc and the feeding system is measured by using a laser vibrometer and the noise level is checked by using microphone. The result shows that the proposed DVA reduces the vibration and. the noise in an optical disc drive.

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Percutaneous Cervical Discectomy using Dekompressor® to the Patient with Posterolateral Extrusion Disc -A case report- (후측면으로 거대 탈출된 경추부 추간판 탈출증 환자에게 Dekompressor®를 이용한 경피적 수핵 감압술 -증례보고-)

  • Jo, Daehyun;Kim, Sangjin;Kim, Myounghee
    • The Korean Journal of Pain
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    • v.19 no.2
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    • pp.253-256
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    • 2006
  • Cervical disc herniation is one of the most common causes of neck, shoulder and arm pain. There are many treatments for a cervical disc herniation, such as rest, physical therapy, medication, epidural steroid injection and surgery. However, conservative treatments sometimes have limited effectiveness, and a surgical discectomy is often associated with numerous complications. Nowadays, a percutaneous discectomy, using a $Dekompressor^{(R)}$, has been used in herniated disc patients, but a posterolateral extruded disc is not an indication. Herein, our experience using a 19 G $Dekompressor^{(R)}$, on a 52 year-old male patient with a left C6-⁣7 posterolateral extruded disc, is reported. Decompression was successfully performed, and the pain and range of motion was immediately improved.

The Effectiveness of Oriental Medical Treatments to Symptoms and Quality of Life in the Patients with Herniated Cervical Disc being Suggested Operation (경추 추간판 탈출증으로 수술 권유를 받은 환자에게 한의학적 치료가 임상증상 및 삶의 질 개선에 미치는 영향)

  • Park, Jong-Min;Lee, Myeong-Jong
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.6 no.1
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    • pp.35-42
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    • 2011
  • Objective : The purpose of this study is evaluated the effects of Oriental treatments to symptoms and quality of life in the patients with herniated cervical disc being suggested operation. Methods : 20 patients diagnosed with herniated cervical disc by MRI in hospital were treated by oriental medical treatments. Symptoms of the patients were assessed by analogue scale(VAS) and SF-36. Results : After 12 weeks treatments, the VAS of symptoms of herniated cervical disc and the score of SF-36 were significantly improved. Conclusions : It could be suggested that oriental medical treatments were effective for the patients with herniated cervical disc being suggested operation. Further study of the effect of oriental medical treatments on herniated cervical disc is needed.

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