• Title/Summary/Keyword: Sectional arch

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The Comparision of the Static Balance, Contact Area, and Plantar Pressure of Flexible Flat Foot According to Elastic Taping

  • Hyeon-Seong Joo;Sam-Ho Park;Myung-Mo Lee
    • Physical Therapy Rehabilitation Science
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    • v.11 no.4
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    • pp.421-429
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    • 2022
  • Objective: The purpose of this study was to compare and analyze the effects of arch support taping on static balance, static/dynamic foot contact area, and ground reaction force during walking according to the types of elastic tapes with mechanical elasticity differences. Design: Cross-sectional study Methods: Twenty-six participants selected for flexible flat feet through the navicular drop test were randomly assigned to non-taping, Dynamic-taping, and Mechano-taping conditions. Static balance and foot contact area were compared in the standing posture according to arch support taping conditions, and foot contact area and ground reaction force were compared during walking. Results: There was no significant difference in static balance according to the taping condition in the standing position, but the foot contact area in the Mechano-taping condition showed a significant decrease compared to the non-taping condition (p<0.05). The foot contact area during walking significantly decreased in the Dynamic-taping and Mechano-taping conditions (p<0.05), but there was no significant difference between the ground reaction force. Conclusions: Based on the results of this study, it was confirmed that among the types of elastic taping, arch support taping using dynamic taping and Mechano-taping has the effect of supporting the arch with high elastic recovery. Any type of elastic tape can be used for arch alignment in flexible flat foot.

Free Vibrations of Tapered Circular Arches with Constant Volume (일정체적 변단면 원호형 아치의 자유진동)

  • Lee, Byoung-Koo;Lee, Tae-Eun;Yoon, Hee-Min;Choi, Jong-Min
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.2
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    • pp.144-152
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    • 2010
  • This paper deals with free vibrations of the tapered circular arches with constant volume, whose cross sectional shape is the solid regular polygon. Volumes of the objective arches are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such arches are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various arch parameters such as rise ratio, section ratio, side number, volume ratio and taper type are reported in tables and figures.

A Clinical Consideration of Orthodontic Force (교정력에 관한 임상적인 소고)

  • Kim, Il-Bong;Ku, Ok-Kyung;Sung, Jae-Hyun;Kim, Yung-Soo
    • The Journal of the Korean dental association
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    • v.11 no.2
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    • pp.123-129
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    • 1973
  • The authors measured orthodontic force using the orthodontic materials of the Rocky Mountain Products Company. The results were as follows : ① Use latex of wide diameter in long distance, and when the latex of wide diameter activated by four or five times, we obtained a optimal force. ② The authors obtained canine retractions with sectional arch. Activation of sectional arch began at 1mm and had to do not activations of 3mm more. ③ The leveling started from .014 green round wire and finished to. 0.16" green Elgiloy round wire. Permit only a mild force in ideal arch form, in rectangular wire. ④ Fundamentaly, elastic thread obtained maximum force by activating as two times. ⑤ Coil spring obtained more heavy force from short distance than long distance.

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Heat Flow Characteristics by Sectional Shapes in Underground Electric Power Tunnel (지하 전력구 단면 형상에 따른 터널내 열유동 특성)

  • Baek, Doo-San;Lee, Seung-Chul;Kwak, Dong-Kurl
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.13-14
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    • 2015
  • This study has conducted a computational analysis to find out about characteristics of heat flow emitted from power lines when the sectional form of electric power tunnel that adopts forced ventilation is shaped like a rectangular, arch or horseshoe. The result of analysis shows that the temperature in the vicinity of the power line peaked at $70^{\circ}C$ when the sectional form is a rectangular, which indicates it is less affected by ventilation than the form of an arch or horseshoe.

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Strength Evaluation on Sectional Members of Prefabricated Precast Concrete Arch with Reinforced Joint (보강된 이음부가 적용된 조립식 프리캐스트 콘크리트 아치의 단면 강도 평가)

  • Joo, Sanghoon;Chung, Chulhun;Bae, Jaehyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.5
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    • pp.1363-1372
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    • 2014
  • In the previous study, the structural performance of proposed precast concrete arch with reinforced joint was evaluated by structural experiment. In this paper, finite element analysis considering both material and contact nonlinearity was carried out on the specimens of the previous study. Based on the result of analysis and experiment, friction coefficient between concrete blocks was determined. To evaluate the strength of sectional member, elastic analysis was carried out on the arch using linear elastic analysis program. The section force was compared with the nominal strength of arch section. It was concluded that the maximum load of all the specimens exceed the nominal strength of arch section. Those results of the strength evaluation were similar to the results of structural experiments. Therefore, it is concluded that the elastic analysis and ultimate strength model can effectively evaluate the strength for the proposed precast concrete arch composed of concrete blocks and reinforced joint in design.

Wind-induced vibration of a cantilever arch rib supported by a flexible cable system

  • Hang Zhang;Zilong Gao;Haojun, Tang;Yongle Li
    • Wind and Structures
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    • v.39 no.1
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    • pp.71-84
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    • 2024
  • The wind-resistant performance of bridges is generally evaluated based on the strip assumption. For the arch rib of arch bridges, the situation is different due to the curve axis and the variable cross-sectional size. In the construction stage, the arch rib supported by a cable system exhibits flexible dynamic characteristics, and the wind-resistant performance attracts specially attention. To evaluate the wind-induced vibration of an arch rib with the maximum cantilever state, the finite element model was established to compute the structural dynamic characteristics. Then, a three-dimensional (3D) fluid-solid coupling analysis method was realized. After verifying the reliability of the method based on a square column, the wind-induced vibration of the arch rib was computed. The vortex-induced vibration (VIV) performance of the arch rib was focused and the flow field characteristics were discussed to explain the VIV phenomenon. The results show that the arch rib with the maximum cantilever state had the possibility of VIV at high wind speeds but the galloping was not observed. The lock-in wind speeds were larger than the results based on the strip assumption. Due to the vibration of arch rib, the frequency of shedding vortices along the arch axis trended to be uniform.

THREE DIMENTIONAL FORCE ANALYSIS OF FORCE SYSTEM IN CONTINUOUS ARCHWIRE BY FINITE ELEMENT METHOD (CONTINUOUS ARCHWIRE의 FORCE SYSTEM에 대한 3차원 유한 요소법적 연구)

  • Row, Joon;Ryu, Young-Kyu
    • The korean journal of orthodontics
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    • v.26 no.1 s.54
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    • pp.17-32
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    • 1996
  • It is important to understand the operating mechanism and force system of fixed appliance that most effective for individual tooth movement in various orthodontic appliances. The archwire system of fixed appliance is devided into 3 types, which is continuous arch, segmented arch and sectional arch. The last two types have longer interbracket distance and simple force operating points, so it is easy to control force system by operator. But the continuous arch has shorter interbracket distance and various bracket geometry, so it is hard to control and anaylze the force system. The purpose of this study was three dimentional force and moment analysis of continuous arch system by finite element method, which is similar situation to three dimentional elastic beam in structural engineering. Several sample form of various bracket geometry and artificial lower crowding typodont made by author were constructed, analyzed and compared each other. The results were as follows : 1. The force magnitude is linear proportional to the degree of displacement or tilting of the bracket. 2. The force magnitude is inversely non-linear proportional to the interbracket distance. 3. In three dimensional typodont model, while the force can be compared with that of the sample form in the area where adjacent bracket geometry is simple, the force is much more than the expected value in the area where adjacent bracket geometry is complex.

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Aortic Arch Variants and Anomalies: Embryology, Imaging Findings, and Clinical Considerations

  • Sang Bin Bae;Eun-Ju Kang;Ki Seok Choo;Jongmin Lee;Sang Hyeon Kim;Kyoung Jae Lim;Heejin Kwon
    • Journal of Cardiovascular Imaging
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    • v.30 no.4
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    • pp.231-262
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    • 2022
  • There is a wide spectrum of congenital anomalies or variations of the aortic arch, ranging from non-symptomatic variations that are mostly detected incidentally to clinically symptomatic variations that cause severe respiratory distress or esophageal compression. Some of these may be accompanied by other congenital heart diseases or chromosomal anomalies. The widespread use of multidetector computed tomography (CT) in clinical practice has resulted in incidental detection of several variations of the aortic arch in adults. Thus, radiologists and clinicians should be aware of the classification of aortic arch anomalies and carefully look for imaging features associated with a high risk of clinical symptoms. Understanding the embryological development of the aortic arch aids in the classification of various subtypes of aortic arch anomalies and variants. For accurate diagnosis and precise evaluation of aortic arch anomalies, cross-sectional imaging modalities, such as multidetector CT or magnetic resonance imaging, play an important role by providing three-dimensional reconstructed images. In this review, we describe the embryological development of the thoracic aorta and discuss variations and anomalies of the aortic arch along with their clinical implications.

A Study on Optimum design of Corrugated web girder using Eurocode (유로코드를 이용한 주름웨브보의 최적설계 연구)

  • Shon, Su-Deok;Yoo, Mi-Na;Lee, Seung-Jae
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.4
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    • pp.47-56
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    • 2012
  • This paper describes the structural design and optimization of sinusoidally corrugated web girder by using EUROCODE (EN 1993-1-5). The optimum design methodology and characteristics of the optimal cross-section are discussed. We investigate a shear buckling and the concerned standards for corrugated web and explain the equations to obtain a critical stress according to buckling type. In order to perform optimization, we consider an objective function as minimum weight of the girder and use the constraint functions as slenderness ratio and stresses of flanges as well as corrugated web and deflection. Genetic Algorithm is adopted to search a global optimum solution for this mathematical model. For numerical example, the clamped girder under the concentrated load is considered, while the optimum cross-sectional area and design variables are analyzed. From the results of the adopted example, the optimum design program of the sinusoidally corrugated web girder is able to find the suitable solution which satisfied a condition subject to constraint functions. The optimum design shows the tendency to decrease the cross-sectional area with the yielding strength increase and increase the areas with load increase. Moreover, the corrugated web thickness shows a stable increase concerning the load.

A Study on Strength Characteristics of Yieldable Steel Arch Supports (가축성 강재 지보의 강도특성에 관한 연구)

  • 김종우
    • Tunnel and Underground Space
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    • v.8 no.4
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    • pp.261-274
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    • 1998
  • The brief results of laboratory and field tests of yieldable steel arches are represented. The test supports were fabricated with three U-sectional beams which are 25.8 kg/m of Glocken profile. The structural analyses of semi-circular and arch supports were conducted to find out shape factor of U beam to be 1.35 and the location of 2nd plastic hinges. Load capacity of arch supports under crown loading were examined as a function of leg length. Yieldable characheristics of test supports were investigated with various bolting torque of connection part. Determination method of bolting torque were also studied. Finally, test supports were installed in-situ with torque of 21 kg .m, which showed a typical yielding procedure.

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