• Title/Summary/Keyword: Passive resistance

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Combined Effects of Gastrocnemius Stretch and Tibialis Anterior Resistance Exercise in Subjects with Limited Ankle Dorsiflexion

  • Lee, Jihyun;Cynn, Heonseock;Shin, Areum;Kim, Bobeen
    • Physical Therapy Rehabilitation Science
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    • v.10 no.1
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    • pp.10-15
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    • 2021
  • Objective: Limited ankle dorsiflexion is related to ankle injuries. There are various exercises to increase the flexibility of the gastrocnemius for improving the passive range of motion in ankle dorsiflexion. However, to performances in daily activities and athletic sports and higher efficiency of walking and running, both ankle dorsiflexion passive and active range of motion are needed. To investigate the effects of combined gastrocnemius stretching and tibialis anterior resistance exercise on ankle kinematics (passive and active range of motion of ankle dorsiflexion) and tibialis anterior muscle activity in subjects with limited ankle dorsiflexion. Design: Cross-sectional single-group repeated measures design. Methods: Fourteen subjects with limited ankle dorsiflexion were recruited (in the right ankle in 7 and the left ankle in 7). All subjects performed gastrocnemius stretching alone and tibialis anterior resistance exercise after gastrocnemius stretching. The passive and active range of motion of ankle dorsiflexion were measured after interventions immediately. The tibialis anterior activity was measured during active range of motion of ankle dorsiflexion measurement. Results: There was no significant difference of ankle dorsiflexion passive range of motion between gastrocnemius stretching alone and the tibialis anterior resistance exercise after gastrocnemius stretching. The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased active range of motion of ankle dorsiflexion compared to gastrocnemius stretching alone (p<0.05). The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased tibialis anterior activity better than did gastrocnemius stretching alone. Conclusions: Thus, subjects with limited ankle dorsiflexion should be encouraged to perform tibialis anterior resistance exercises.

Evaluation of Corrosion Resistance Properties by Applying Galvanostatic Nanoscale Current Density on Passive Metals

  • Na, Seung-Chan;Lee, Jeong-Ja;Yang, Won-Seog;Hwang, Woon-Suk
    • Corrosion Science and Technology
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    • v.6 no.1
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    • pp.7-11
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    • 2007
  • In this study, new evaluation method for the stability and corrosion resistance properties of passive films has been suggested by means of observation of self-activation process in open-circuit state and galvanostatic nanoscale reduction test. The experiments were performed for air-formed oxide film in case of plain carbon steel, and for anodically passivated films formed in aqueous sulfuric acid solutions in case of titanium and 304 stainless steel. From these experimental results, we derived two parameters, $i_{0}$ and $q_{0}$, which characterize the self-activation process and the properties of passive film on a stainless steel surface. The parameter $i_{0}$ was defined as the rate of self-activation, and $q_{0}$, the reduced amount of charge during the self-activation process. In conclusion, it is considered that the stability and corrosion resistance of passive metals and alloys can be evaluated quantitatively by three parameters of $\tau_{0}$, $q_{0}$, and $i_{0}$, which easily obtain by means of observing the self-activation process and galvanostatic nanoscale reduction test.

Pullout Resistance of Geosynthetic Strip with Rounded Band Anchor (수동저항부가 형성된 띠형 섬유보강재의 인발저항 특성)

  • Lee, Kwang-Wu;Cho, Sam-Deok;Han, Jung-Geun;Hong, Ki-Kwon
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.3
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    • pp.43-51
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    • 2011
  • This paper describes the results of pullout tests in the laboratory, which are conducted to assess the pullout performance of recently developed geosynthetic strip reinforcement with rounded band anchor. The geosynthetic strip can be used as reinforcements in reinforced soil wall with concrete block facing. The pullout resistance of the geosynthetic strip with rounded band anchor is mobilized by the combination of the interface friction between soil-reinforcement surface and the passive soil resistance caused by the rounded band anchor. Therefore, both the friction resistance and the passive resistance have to be considered in design. From the pullout test results, when the rounded band anchor are formed in the end part of the geosynthetic strip, pullout strength increases about from 10% to 65%. The passive resistance can be evaluated based on the pullout test results.

A Study on Anti-Oxidation of Stainless Steel Spot Weld (스테인리스강 Spot 용접부의 산화방지에 관한 연구)

  • Huh, Dong-Woon;Rhee, Se-Hun
    • Journal of Welding and Joining
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    • v.29 no.5
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    • pp.58-62
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    • 2011
  • Stainless steels are alloy steels with a nominal chromium content of at least 11 percent, with other alloy additions. The stainlessness and corrosion resistance of these alloy steels are attributed to the presence of a passive oxide film on the surface. When exposed to conditions like Resistance Spot Welding (RSW) process that remove the passive oxide film, stainless steels are subject to corrosive attack. And exposure to elevated temperatures causes oxidation (discoloration) of areas around indentation in Spot welding. In this paper, deal with the effect of shielding gas (Ar) preventing the corrosion, oxidation of stainless steel. And find the optimal shielding gas flow rate. In addition, suggest effective purging method for direct/indirect spot welding process.

A Study on the Rectangular-Shaped Passive Row Piles in Inclined Sand-Ground by Model Test (경사모래지반의 사각형 수동 열말뚝에 관한 실험적 연구)

  • Bae, Jong-Soon;Kim, Ji-Seong;Kwon, Min-Jae
    • Journal of the Korean Geotechnical Society
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    • v.25 no.11
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    • pp.39-51
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    • 2009
  • This is a study on rectangular-shaped passive row piles in inclined sand-ground by model tests. The experiment controlled the angle of inclination of ground and induced the ground destruction. We also measured the behavior of row piles, by adjusting the shape, position and spacing of piles. As a result, we confirmed the earth pressure, the lateral resistance, and the effect of depressing on the ground variation working on passive pile. The effect of B-type pile of which the front width is wide is bigger than that of H-type pile of which the side width is wide. We can find out the failure angle of slope, the shared force of pile and soil by using the lateral resistance graph based on slope angle.

A Study on Resistance in Rapper Fashion (랩퍼(Rapper) 패션에 나타난 저항성(抵抗性) 연구(硏究))

  • Kwon, Hyuk-Ju;Yang, Suk-Hee
    • Journal of Fashion Business
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    • v.5 no.1
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    • pp.53-71
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    • 2001
  • The purpose of this study how 'Afro-American resistance' is showed up in the fashion trough the study of rapper's fashion present in singing rap music. Rap music produced by the influence of black music. It have been the tool of expression of pain and sorrow of their lives and included their resistant spirit. So rapper's fashion expressed resistance. at this point I categorized the resistant feature of rapper's fashion at two types in terms of the extent of expression. Their are active resistance fashion and passive resistance fashion. Also each fashion types was classified in terms of style, material, color, accessories and so forth. Active fashion is possible to classify these three styles as follows. The first one is Afrocentic style that was raised from longing for Africa. The second one is Military style which contains an ling-time enduring spirit of resistance against the society. The last one is Hiphop style that violated the typical rule of dressing under the hiphop style culture. these kinds of active resistance are also classified as material like blue Jean showing black workers' resistance, color like black showing off superiority of 'black' and red, gold and green color expressing black people's resistance, and other accessories like chains, cross and so on. Passive resistance fashion has several variations according to the style. There are Jazz style, Uniform style and Hiphop style. It is also categorized as high-tech materials, white color which is the expression of desire for white and luxurious accessories showing off wealth.

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Effect of seismic acceleration directions on dynamic earth pressures in retaining structures

  • Nian, Ting-Kai;Liu, Bo;Han, Jie;Huang, Run-Qiu
    • Geomechanics and Engineering
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    • v.7 no.3
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    • pp.263-277
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    • 2014
  • In the conventional design of retaining structures in a seismic zone, seismic inertia forces are commonly assumed to act upwards and towards the wall facing to cause a maximum active thrust or act upwards and towards the backfill to cause a minimum passive resistance. However, under certain circumstances this design approach might underestimate the dynamic active thrust or overestimate the dynamic passive resistance acting on a rigid retaining structure. In this study, a new analytical method for dynamic active and passive forces in c-${\phi}$ soils with an infinite slope was proposed based on the Rankine earth pressure theory and the Mohr-Coulomb yield criterion, to investigate the influence of seismic inertia force directions on the total active and passive forces. Four combinations of seismic acceleration with both vertical (upwards or downwards) and horizontal (towards the wall or backfill) directions, were considered. A series of dimensionless dynamic active and passive force charts were developed to evaluate the key influence factors, such as backfill inclination ${\beta}$, dimensionless cohesion $c/{\gamma}H$, friction angle ${\phi}$, horizontal and vertical seismic coefficients, $k _h$ and $k_v$. A comparative study shows that a combination of downward and towards-the-wall seismic inertia forces causes a maximum active thrust while a combination of upward and towards-the-wall seismic inertia forces causes a minimum passive resistance. This finding is recommended for use in the design of retaining structures in a seismic zone.

An Experimental Study on Passive Earth Pressure of 3-Dimension (3차원 수동토압에 관한 실험적 연구)

  • 김기동;이상덕
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.10a
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    • pp.489-496
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    • 1999
  • The safety of a structure can be improved by applying the three dimensional passive earth pressure. Because the three dimensional passive earth pressure is much larger than the two dimensional passive earth pressure and it is determined by the size(width B and height H) and the wall frictional angle of the resistant wall. Therefore, the three dimensional passive resistance behavior was studied through the model tests in sandy ground, where the size of the resistant wall and the wall frictional angle were varied. The results show that three dimensional passive earth pressure is 1.1∼3.4 times larger than that of the two dimensional value depending on the wall size and the wall friction.

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