• Title/Summary/Keyword: lateral pressure

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Effects of Combined Wedge on Angle and Moment of Ankle and Knee Joint During Gait in Patients With Genu Varus

  • Yang, Hae Sun;Choi, Houng Sik
    • Journal of International Academy of Physical Therapy Research
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    • v.7 no.2
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    • pp.1025-1030
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    • 2016
  • The purpose of this study was to investigate the effects of combined wedge on the range of motion in ankle and knee joint, ankle eversion moment and knee adduction moment, and center of pressure excursion of foot for genu varus among adult men during gait. This study was carried out with 10 adult men for genu varus in a motion analysis laboratory in J university. The subjects of the experiment were measured above 5cm width between the knees on contact of both medial malleolus of ankle while standing. The width of their knees in neutral position was measured without the inversion or eversion of the subtalar joint by the investigator. The subjects of the experiment were ten who were conducted randomly for standard insole, insole with $10^{\circ}$ lateral on rear foot wedge, insole at $10^{\circ}$lateral on rear foot and $5^{\circ}$ medial on fore foot wedge. Before and after intervention, changes on the range of motion in ankle and knee joint, ankle eversion moment and knee adduction moment, and center of pressure excursion were measured. In order to compare analyses among groups; repeated one-way ANOVA and $Scheff{\acute{e}}$ post hoc test were used. As a result, combined wedge group was significantly decreased compared to control wedge group in terms of knee varus angle in mid-stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge group in terms of ankle eversion moment in whole stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge group in terms of knee adduction moment in whole stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge in terms of center of pressure excursion in whole stance(p<.05). The results of this study suggest that combined wedge for genu varus decreased ankle eversion moment and knee adduction moment upon center of pressure excursion. We hypothesize that combined wedge may also be effective in the protection excessive ankle pronation.

Rotation Point of Laterally Loaded Pile Under Multi Layered Soil (다층지반 하에서 수평하중을 받는 말뚝의 회전점)

  • Kang, Beong-Joon;Kyung, Doo-Hyun;Hong, Jung-Moo;Lee, Jun-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.708-712
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    • 2008
  • Piles and pile foundations have been in common use since very early times. Usually function of piles is to carry load to a depth at which adequate support is available. Another important use of piles is to furnish lateral support and nowadays it is getting highlighted due to the wind load, lateral action of earthquake, and so on. After Broms (1964), many researchers have been suggested methods for estimating lateral capacity of pile. But each method assumes different earth pressure distribution and lateral earth pressure coefficient and it gives confusion to pile designers. Lateral earth pressure, essential in lateral capacity estimation, influenced by pile's behavior under lateral load. Prasad and Chari (1999) assumed the rotation point of pile and suggested an equation of ultimate lateral load capacity. In this study, we investigate the depth of rotation point in both homogeneous soil and multi layered soil, and compare to the estimation value by previous research. To model the pile set up in the sand, we use the chamber and small scale steel pile, and rain drop method. Test results show the rotation point is formed where the Prasad and Chari's estimation value, and they also show multi layered condition affects to location of rotation point to be scattered.

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Numerical Investigation of the Lateral Jet Effect on the Aerodynamic Characteristics of the Missile: Part I. Jet Flow Condition Effect (측 추력 제트가 미사일의 공력특성에 미치는 영향에 관한 연구 : Part I. 제트 유동특성 영향)

  • Min, Byung-Young;Lee, Jae-Woo;Byun, Yung-Hwan;Hyun, Jae-Soo;Kim, Sang-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.8
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    • pp.64-71
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    • 2004
  • A computational study on the supersonic flow around the lateral jet controlled missile has been performed. For this purpose a three dimensional Navier-Stokes computer code(AADL3D) has been developed and case studies have been performed by comparing the normal force coefficient and the moment coefficient of a missile body for different jet flow conditions including jet pressure and jet Mach number. The results show different behavior of normal force and moment variation according to jet pressure variation and jet Mach number variation. From the detailed flow field analyses, it is verified that most of the normal force loss and the pitching moment generation are taken place at the low-pressure region behind the jet nozzle. Furthermore, it is shown that the pitching moment can be efficiently reduced by obtaining the lateral thrust through higher jet Mach number rather than through high jet pressure.

Influence of eccentric load and lateral earth pressure on the tunnel behavior (편토압 및 측압이 터널거동에 미치는 영향)

  • Ahn, Hyun-Ho;Suh, Byung-Wook;Kim, Dong-Hyun;Min, Dong-Ho;Lee, Sun-Bok;Lee, Seok-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.3
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    • pp.219-228
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    • 2007
  • Scaled model tests were performed to explore the influence of eccentric load and lateral earth pressure on tunnel behavior and their results were verified through numerical analyses. As a method for reducing the eccentric load acting on tunnel, an eccentric supporting system (ESS) was proposed and its applicability was investigated. Experimental results showed that displacement decreased overall and the load inducing initial cracks increased as the eccentric supporting system was applied. The maximum eccentric vertical load which impacted the stability of tunnel was also increased. The test results on the influence of lateral earth pressure on tunnel behavior showed that the general aspect of displacement and crack growth changed significantly depending on the coefficient of lateral earth pressure. In addition, the weak zone In view of stability varied as well.

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Biomechanical Behaviors of Disc Degeneration on Bending Loads (굽힘하중에 대한 퇴행성 추간판의 생체역학적 특성 분석)

  • Lee, Hyun-Ok;Lee, Sung-Jae;Shin, Jung-Woog
    • The Journal of Korean Physical Therapy
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    • v.13 no.1
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    • pp.1-18
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    • 2001
  • Aging has been recognized as the primary cause of disc degeneration. A biomechanical characteristics of disc degeneration has been demonstrated that intradiscal pressure is reduced. With the increasing population of elderly people, disc degeneration and associated problems of nerve entrapment are becoming more prevalent. Presently, research on reduced intradiscal pressure associated with degeneration is insufficient. In this study. we used the Finite Element Method (FEM) of computerized simulations to investigate the effects of variation in intradiscal pressure on mechanical behaviours of L4-5 intervertebral disc degeneration. Degeneration was classified using four grades based on initial intradiscal pressure; Normal (135 kPa), mild(107 kPa), moderate (47 kPa) and severe (15 kPa). The predicted results f3r bending loads were as follows; 1 . Range of motion increased progressively with severity of degeneration with flexion and lateral bending moments, but decreased with extension moments. 2. Discal bulging of posterolateral aspect was larger in lateral bending and extension moment. But bulging was increased with severity of degeneration in lateral bending and torsion(same side).3. The rate of increasing intradiscal pressure was decreased in all bending motions with severity of degeneration. In conclusion, lateral bending and extension moment yield greatest bulging in severe degeneration. In torsion, although bending load produces disc bulging, disc bulging was associated more strongly with severity of degeneration than increasing torsional moments. Clinical Implications: Discal bulging may produce nerve root impingement and irritation. The effect of loading and posture on the varying degrees of disc degeneration has important implications especially in the elderly. In the presence of disc degeneration, avoidance of end range postures, especially extension and lateral bending may help reduce discal bulging and in turn, nerve entrapment.

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A Study on the Lateral Earthpressure at Behind Structure for Backfill by Sand (구조물 배면에 사질토 되메움시 유발되는 수평토압에 관한연구)

  • Lee, Sang-Duk;Kang, Se-Gu
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.4
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    • pp.11-18
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    • 2011
  • In this study, the reinforcing effect of geogrids in the narrow backfill by sand was experimentally studied. In the model tests, the size of space and the slope of the cut off slope were varied out. The resultant and the distribution of lateral earth pressure were measured. Width of backfill space varied 10 cm, 20 cm, 30 cm at the lower wall level and angle of the cut off slope varied $90^{\circ}$, $75^{\circ}$, $60^{\circ}$. Geogrids were installed in the backfill. Measured results showed that the distribution of the lateral earth pressure due to the narrow backfill developed in a arching shape. And the earth pressure was reduced due to the reinforcement of the backfill by geogrid. geogrid helps reduction of lateral earth pressure.

Behavior of the Segment Lining due to the Middle Slab and the Lateral Pressure Coefficient in Duplex Tunnel (복층터널에서 중간슬래브와 측압계수에 따른 세그먼트 라이닝의 거동분석)

  • Lee, Ho Seong;Moon, Hyun Koo
    • Tunnel and Underground Space
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    • v.26 no.3
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    • pp.192-200
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    • 2016
  • We analyzed the behavior of the lining segments considering the middle slab and lateral pressure coefficients when planning the construction of a duplex tunnel for the underground network. Reviewed segment lining analysis for research, the analytical model was determined for duplex tunnel. Also reviewed the vertical load, and a load of middle slab is considered the static load and the live load by vehicles. Section force by middle slabs a load applied was mainly generated in the lower tunnel had the greatest effect on the bending moment. In addition, the bending moment acting direction changes appeared with a large variable, and the section force according to the load applied to the middle slab is relatively constant and the effect on the segment lining from the smallest section force of the lateral pressure coefficient of 1.00 was found to occur appears most significantly. As a result of this research to identify the behavior of the slab and the segment lining by the effect of the lateral pressure coefficient (K) of the duplex tunnel will be able to present a method of the duplex tunnel structure is reasonable and economical design.

A Comparative Study of the Plantar Foot Pressure according to the Form of Foot Angle during Level Walking (평지 보행 시 발 각도 형태에 따른 발바닥 압력 비교 연구)

  • Lee, Jeon-Hyeong;Kim, Ki-Chul;Kuk, Jung-Suk
    • PNF and Movement
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    • v.12 no.2
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    • pp.89-96
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    • 2014
  • Purpose: The purpose of this study was to examine the influence of foot angles on plantar pressure and the center of pressure (COP) trajectory length during level walking. Methods: The study subjects were 30 female university students without orthopedic diseases in the foot. The foot angle was divided into three forms (out-toeing, normal, in-toeing). The subjects practiced each type of gait, and then performed each of level walking, three times, and their averages were calculated. A plantar pressure measurement instrument was used, and the maximum force was obtained by dividing the foot into nine regions covering the anterior medial-lateral, middle medial-lateral, and posterior medial-lateral. The COP trajectory length was statistically processed by obtaining medial-lateral, anterior-posterior, and entire travel distance. Results: During normal walking, the maximum force was significantly higher in the anterior lateral than in the other areas, and the COP trajectory length was significantly shorter in the front-back and entire travel distances (p<0.05). During stair climbing. Conclusion: Walking at abnormal foot angles does not cause appreciable problems in the short term as pressure is concentrated on a specific plantar part. However, it becomes the cause of deformed foot structures and can result in musculoskeletal disabilities in the long term. Therefore, a kinesiatrics-based intervention is required to maintain normal foot angles.

An Experimental Study on the Measuring Lateral Formwork Pressure Controlled by Super-Workable Fresh Concrete (고유동 콘크리트의 거푸집 측압 측정에 관한 실험적 연구)

  • 이준구;박광수;김한중;배수호
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.142-145
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    • 1998
  • The purpose of this study is to estimate lateral formwork pressure controlled by super-workable fresh concrete using prototype structrues such as, tall wall, retaining wall, and beam quantitativly. As a result of this experiment, a function which can be used to design a formwork system and to predict formwork pressure curve is formulated.

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Effects of quadriceps angle on patellofemoral contact pressure

  • Yoo, Yoon-Hyeong;Lee, Sung-Jun;Jeong, Soon-wuk
    • Journal of Veterinary Science
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    • v.21 no.5
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    • pp.69.1-69.11
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    • 2020
  • Background: An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint. Objectives: The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs. Methods: Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared. Results: Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P ≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001). Conclusions: Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided.