• Title/Summary/Keyword: Extension Surface

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The Effect of Cervical & Lumbar Range of Motion According to Plantar Surface Compliance (족저 접촉면의 경도가 경추와 요추의 가동범위에 미치는 영향)

  • Cho, Hyun-Rae;Chae, Jung-Byung
    • PNF and Movement
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    • v.5 no.1
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    • pp.1-8
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    • 2007
  • Purposes : The purpose of this study was to measurement the change of cervical and lumbar range of motion according to plantar surface compliance in standing status. Method : The thirty normal adult(15men and 15women) aged between 20 and 35 were assigned to 3 group: first, in bottom piece shoe plantar form not changed the control group, the fore foot which was hard and the rear foot was soft the FHRS Group, the fore foot which was soft and the rear foot was hard the FSRH Group. The cervical and lumbar Range of motion was examined before and after adaptation with corresponding form types Results : This study investigated the change which appears when it will be soft and hard to be. As a result, FHRS group the cervical extension and lumbar flexion increased and the cervical flexion and lumbar extension decreased(p<0.05). In opposition, the FSRH group the cervical flexion and lumbar extension increased and the cervical extension and lumbar flexion decreased(p<0.05).

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The Generation of a Smooth C Extension Surface (부드러운 $C^2$확장 곡면 생성)

  • 김회섭
    • Korean Journal of Computational Design and Engineering
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    • v.9 no.2
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    • pp.143-147
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    • 2004
  • To design parts satisfying physical property in the continuous region, we do it in the discrete rectangular mesh points. Then we obtain points data from parts design and usually construct the surface using least squares method. In such case, that surface has an oscillation in the ineffective region which is inadequate for physical phenomena or NC machining. To solve both problems simultaneously, we extend the surface smoothly to have small curvature in the extended region. Up to now, we use the least squares method for the parts design in Color Picture Tube or Color Display Tube but in this paper, we use functions which is easily controllable. This surface has no error within the effective region compared to the least squares method.

Modifying a Back Endurance Test for Examining Erector Spine Muscles by Adding Lateral Trunk Bending and Trunk Rotation

  • Park, Se-Yeon;Park, Du-Jin
    • PNF and Movement
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    • v.15 no.3
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    • pp.381-387
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    • 2017
  • Purpose: Although some studies indicate that the Sorensen test may not be used to examine back muscles such as the erector spinae, alternatives to the back-extension test are rarely suggested. Therefore, the purpose of the present study was to investigate an effective way to stimulate the erector spinae muscles by adding a component of trunk rotation and lateral bending to general back extensions. Methods: A total of 18 healthy, physically active participants performed simple trunk extension, extension with trunk rotation, and extension with lateral bending. Surface electromyography responses of the latissimus dorsi, thoracic, and lumbar levels of the erector spinae; the gluteus maximus; and the biceps femoris muscles were investigated during these 3 conditions of modified back extension tests. Results: The simple trunk extension exercise caused significant increases in activity of the gluteus maximus and biceps femoris muscles as compared to the extension with rotation and lateral bending exercises. The extension with trunk rotation exercise showed significantly greater activation in the thoracic and lumbar levels of the erector spinae and in the latissimus dorsi as compared to the other exercises. The index measuring subjective difficulty was significantly lower in the simple trunk extension exercise as compared to the extension with trunk rotation and extension with lateral bending exercises. Conclusion: The present study suggests that extension with trunk rotation has the advantage of stimulating the para-spinal muscles, while simple trunk extension may not be adequate to selectively simulate the para-spinal muscles but may be appropriate for examining global trunk extensors.

Analysis of Activation and Contribution of Muscles of the Elderly During Arm Flexion and Extension Resistance Exercise with Increased Load (노인의 팔 굽힘/폄 저항 운동 시 하중 증가에 따른 근육의 활성도 및 기여도 분석)

  • Kim, Hyun-Dong;Hwang, Sung-Jae;Son, Jong-Sang;Kim, Han-Sung;Kim, Young-Ho
    • Journal of the Ergonomics Society of Korea
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    • v.28 no.4
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    • pp.17-23
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    • 2009
  • The purpose of this study was to assess activation and contribution of muscles of the elderly according to increased loading during the arm flexion extension resistance exercise. Surface electromyographic signals were acquired from biceps brachii, triceps brachii, deltoid posterior, pectoralis major and latissimmus dorsi to determine the difference of the activation of specific muscles between the elderly and young. Five elderly and five young males with no musculoskeletal disease volunteered for the study. Electromyographic activities in the muscles were measured during resistance exercise and normalized to the maximum EMG activity recorded in the maximal voluntary static contraction (MVC). Against the increased loading during arm flexion/extension resistance exercises, the young uses muscles evenly but the elderly uses one specific muscle frequently. Contribution of triceps brachii during extension and deltoid posterior during flexion was principal in the elderly.

Observation of the Vortex Interaction over an Yawed Delta Wing with Leading Edge Extension by Flow Visualization and 5-hole Probe Measurements (가시화와 5공 프로브 측정을 통한 연장된 앞전을 갖는 편요된 델타형 날개에서의 와류 상호작용 관찰)

  • Sohn, Myong-Hwan;Lee, Ki-Young
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.388-393
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    • 2001
  • An experimental study is conducted to investigate the interaction of vortices over a delta wing with leading edge extension(LEX) through the off-surface flow visualization and the 5-hole probe measurements of the wing wake region. Especially, the application of a new visualization technique is employed by ultrasonic humidifier water droplet and laser beam sheet. The results, both the off-surface visualization and the 5-hole probe, show that LEX tends to stabilize the vortices of the delta wing up to the high angle of attack even though the model is yawed. With increasing yaw, the windward leading edge vortex moves inward, and closer to the wing surface, while the leeward vortex moves outwards and away from the wing surface. The vortex interaction is promoted in the windward side, and is delayed in the leeward side.

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Estimation of Stellate Ganglion Block Injection Point Using the Cricoid Cartilage as Landmark Through X-ray Review

  • Park, Jeong-Soo;Kim, Ki-Jun;Lee, Youn-Woo;Yoon, Duck-Mi;Yoon, Kyung-Bong;Han, Min-Young;Choi, Jong-Bum
    • The Korean Journal of Pain
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    • v.24 no.3
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    • pp.141-145
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    • 2011
  • Background: Stellate ganglion block is usually performed at the transverse process of C6, because the vertebral artery is located anterior to the transverse process of C7. The purpose of this study is to estimate the location of the transverse process of C6 using the cricoid cartilage in the performance of stellate ganglion block. Methods: We reviewed cervical lateral neutral-flexion-extension views of 48 patients who visited our pain clinic between January and June of 2010. We drew a horizontal line at the surface of the cricoid cartilage in the neutral and extension views of cervical lateral x-rays. We then measured the change in the shortest distance from this horizontal line to the lowest point of the transverse process of C6 between the neutral and extension views. Results: There was a statistically significant difference in the shortest distance from the horizontal line at the surface of the cricoid cartilage to the lowest point of transverse process of C6 between neutral position and neck extension position in both males and females, and between males and females in both neutral position and neck extension position. The cricoid cartilage level was 4.8 mm lower in males and 14.4 mm higher in females than the lowest point of transverse process of C6 in neck extension position. Conclusions: Practitioners should recognize that the cricoid cartilage has cephalad movement in neck extension. In this way, the cricoid cartilage can be still useful as a landmark for stellate ganglion block.

The effect of TiN and coating parameters on the tool life extension (TiN 및 TiCN 코팅 특성이 공구수명에 미치는 영향에 대한 연구)

  • 백영남;정우창
    • Journal of the Korean institute of surface engineering
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    • v.31 no.6
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    • pp.317-324
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    • 1998
  • TiN and TiCN films were deposited on the high speed steel by Cathode Arc Ion Plating(CAIP) Process to investigate the tool life extension effect. The experiment variables were bias voltage and deposit time for the TiN coating and reactive gas flow rate ($CH_4:N_2$) under fixing deposit pressure, are current, bias voltage for the TiCN coating respectively. The micro structure and mechanical properties were investigated and compared for among the coating conditions using various methods and machining practice.

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The Mechanics of Crack Formation Induced by Sliding on a Brittle Material (슬라이딩에 의해 취성재료에 발생하는 균열 성장에 관한 연구)

  • Kim, J.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.11
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    • pp.36-44
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    • 1995
  • When sliding a hard cylinder along the surface of glass, periodic surface cracks appear on the flat surface due to tensile stresses induced by the slider. These cracks propagate into the substrate and will affect the fracture properties of a body. Crack spacings and the directions of crack propagation into glass were calculated numerically by applying the finite element method and linear elastic fracture mechanics. The calculated crack spacings were in the range of the experimental results. Stress intensity factors and crack extension angles depended on the radius of slider and the load, and from these two factors the possible directions of crack propagation were calculated. The calculated propagation directions were in good agreement with real crack propagation.

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Finite Element Simulation of Surface Pitting due to Contact Fatigue (접촉피로에 의한 표면피팅의 유한요소 시뮬레이션)

  • Rhee, Hwan-Woo;Kim, Sung-Hun
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.3
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    • pp.80-88
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    • 2010
  • A simple computational model for modeling of subsurface crack growth under cyclic contact loading is presented. In this model, it is assumed that the initial fatigue crack will initiate in the region of the maximum equivalent stress at certain depth under the contacting surface. The position and magnitude of the maximum equivalent stress are determined by using the equivalent contact model, which is based on the Hertzian contact conditions with frictional forces. The virtual crack extension method is used for simulation of the fatigue crack growth from the initial crack up to the formation of the surface pit due to contact fatigue. The relationships between the stress intensity factor and crack length are then determined for various combinations of equivalent contact radii and loadings.