• Title/Summary/Keyword: Base condition

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FINITE ELEMENT ANALYSIS OF MANDIBULAR STRESSES AND DENTURE MOVEMENTS INDUCED BY OVERDENTURES (Overdenture 하에서 하악응력 및 의치의 변위에 관한 유한요소법적 분석)

  • Kim, Joung-Hee;Chung, Chae-Heon;Cho, Kyu-Zong
    • The Journal of Korean Academy of Prosthodontics
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    • v.28 no.1
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    • pp.63-94
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    • 1990
  • The purpose of this study was to analyze the displacement and the magnitude and the mode of distribution of the stresses in the lower overdenture, the mucous membrane, the abutment tooth and the mandibular supporting bone when various denture base materials, such as acrylic resin and 0.5mm metal base, and various denture base designs were subjected to different loading schemes. For this study, the two-dimensional finite element method was used. Mandibular arch models, with only canine remaining, were fabricated. In the first denture base design, a space, approximately 1mm thick, was prepared between the denture and the dome abutment. In the second denture base design, contact between the denture and the dome abutment was eliminated except the contact of the occlusal third of the abutment. In order to represent the same physiological condition as the fixed areas of the mandible under loading schemes, the eight nodes which lie at the mandibular angle region, the coronoid process and the mandibular condyle were assumed to be fixed. Each model was loaded with a magnitude of 10 kgs on the first molar region(P1) and 7 kgs on the central incisal region (P2) in a vertical direction. Then the force of 10 kgs was applied distributively from the first premolar to the second molar of each model in a vertical direction(P3). The results were as follows. : 1. When the testing vertical loads were given to the selected points of the overdenture, the overdenture showed the rotatory phenomenon, as well as sinking and the displacements of alveolar ridge, abutment and lower border of mandible under the metal base overdenture were less than those under the acrylic resin overdenture. 2. The maximum principal stresses(the maximum tensile stresses) being considered, high tensile stresses occured at the buccal shelf area, the posterior region of the ridge crest and the anterior border region of the mandibular ramus. 3. The minimum principal stresses(the maximum compressive stresses) being considered, high compressive stresses occured at the inferior and posterior border region of the mandible, the mandibular angle and the posterior border region of the mandibular ramus. 4. The vertical load on the central incisal region(P2) produced higher equivalent stress in the mandible than that on any other region(P1, P3) because of the long lever arm distance from the fixed points to the loading point. 5. Higher equivalent stresses were distributed throughout the metal base overdenture than the resin base overdenture under the same loading condition. 6. The case of occlusal third contact of the abutment to the denture produced higher equivalent stresses in the abutment, the mandibular area around the abutment and the overdenture than the case of a 1mm space between the denture and the abutment. 7. Without regard to overdenture base materials and designs, the amounts and distribution patterns of equivalent stresses under the same loading condition were similar in the mucous membrane.

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An Experimental Study on the Turning Property of Welded Material (용접부의 선삭특성에 관한 실험적 연구)

  • Jang, Bok-Deuk
    • Journal of the Korean Society for Precision Engineering
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    • v.3 no.3
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    • pp.13-21
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    • 1986
  • Turning property of metal is affected by the cutting condition, tool geome- try and cutting material. But the turning property of welded material is not welknown. Welded structures usually contain nonhomogeneity, defects and resi- dual stresses due to differential contraction between welded metal and base metal. In this paper, authors conducted the experimental test on the turning property, by changing turning condition and welding electrodes of the welded specimens. The results obtained in these experimental tests are as follows; (1) Within the limit of this experimental test, the cutting force of the weld zone is bigger than that of base metal, and this phenomena is caused by the different mechanical property of the weld zone. The range of the variation of cutting force in the weld zone is caused by the nonhomogeneity of the weld zone, respectively. (2) The surface roughness follows the general characteristic of the effect of cutting condition on the surface roughness and the surface roughness of the weld zone shows coarse surface comparing with that of the base metal. (3) The specimen welded by the electrode E4301, shows worse cutting property than that of E4361 and E4313.

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The Effect of Action Observational Physical Training on Manual Dexterity in Stroke Patients (동작관찰훈련이 뇌졸중 환자의 손 조작능력에 미치는 영향)

  • Kim, Jong-Man;Yang, Byoung-Il;Lee, Moon-Kyu
    • Physical Therapy Korea
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    • v.17 no.2
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    • pp.17-24
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    • 2010
  • The aim of this study was to determine the effect of action observational physical training (AOPT) on manual dexterity and corticomotor facilitation in stroke patients. Ten hemiparetic patients participated in this study. Each subject was asked to participate the three conditions; base condition (Base), physical training (PT), AOPT. Participants were asked to observe the action in the video that a therapist moved the blocks during the AOPT conditions. Corticomotor facilitation was determined in three conditions by monitoring changes in the amplitude of motor-evoked potentials (MEPs) elicited in hand muscles by transcranial magnetic stimulation. MEP responses were measured from the first dorsal interosseous after participants attended to three conditions. For the manual dexterity, Box and Block test (BBT) was used. The results of present study were summarized as follows: MEPs amplitude significantly tended to be larger than PT and Base condition. The scores of BBT in the AOPT condition were also significantly larger than other conditions. In conclusion, this finding of present study indicates that physical training for observation of an action is beneficial for enhancing a dexterity of paretic arm in stroke patients.

Short-term fatigue analysis for tower base of a spar-type wind turbine under stochastic wind-wave loads

  • Li, Haoran;Hu, Zhiqiang;Wang, Jin;Meng, Xiangyin
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.1
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    • pp.9-20
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    • 2018
  • Due to integrated stochastic wind and wave loads, the supporting platform of a Floating Offshore Wind Turbine (FOWT) has to bear six Degrees of Freedom (DOF) motion, which makes the random cyclic loads acting on the structural components, for instance the tower base, more complicated than those on bottom-fixed or land-based wind turbines. These cyclic loads may cause unexpected fatigue damages on a FOWT. This paper presents a study on short-term fatigue damage at the tower base of a 5 MW FOWT with a spar-type platform. Fully coupled time-domain simulations code FAST is used and realistic environment conditions are considered to obtain the loads and structural stresses at the tower base. Then the cumulative fatigue damage is calculated based on rainflow counting method and Miner's rule. Moreover, the effects of the simulation length, the wind-wave misalignment, the wind-only condition and the wave-only condition on the fatigue damage are investigated. It is found that the wind and wave induced loads affect the tower base's axial stress separately and in a decoupled way, and the wave-induced fatigue damage is greater than that induced by the wind loads. Under the environment conditions with rated wind speed, the tower base experiences the highest fatigue damage when the joint probability of the wind and wave is included in the calculation. Moreover, it is also found that 1 h simulation length is sufficient to give an appropriate fatigue damage estimated life for FOWT.

Research on the Domain Formation of Living Base Space of Credit System High Schools - Focused on Japanese Comprehensive High Schools - (학점제 고등학교 생활거점공간의 영역 형성에 관한 연구 - 일본의 총합학과 고등학교를 대상으로 -)

  • Son, Suk-Eui;Kim, Seung-je
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.35 no.10
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    • pp.3-10
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    • 2019
  • The high school credit system is a system in which students select complete various subjects, depending on their career, and graduate when their accumulated credit reaches the standard. It is expected that the high school credit system, which guarantees the individual's right of choice, will bring an educational effect that can respond to the student's career aptitude. However, it is expected that problems in the aspect of school life, such as the weakening of class belongingness or difficulty of securing a stable base venue within the school building would be accompanied. This research analyzed students' usage condition depending on the living base space environment feature in schools that are implementing moving-selective class in the aspect of activity domain formation and contemplated the venue evaluation. The purpose is to provide the basic data of an architectural plan of a stable living base space within the school building through this. 'Living base center type' and 'living base dispersion type' school buildings among Japanese integral department high schools were used as the target to analyze the usage condition in the aspect of domain formation. As a result, a conclusion was deducted that student's securement of territory consciousness about the base space and venue construction for the community of various studying groups affects life satisfaction.

Performance Analysis of a Geometrically Asymmetric Trapezoidal Fin for an Enhanced Heat Exchanger (향상된 열교환기를 위한 기하학적 비대칭 사다리꼴 핀의 성능 해석)

  • Song, Nyeon-Joo;Kang, Hyung-Suk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.4
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    • pp.24-31
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    • 2011
  • Performance of the asymmetric trapezoidal fin with various upper lateral surface slopes is investigated by using the two-dimensional analytic method. For a fin base boundary condition, convection from the inner fluid to the inner wall, conduction from the inner wall to the fin base and conduction through the fin base are considered. Heat loss and fin efficiency are represented as a function of the fin base thickness, base height, inner fluid convection characteristic number, fin tip length and fin shape factor. One of the results shows that heat loss increases while fin efficiency decreases as the fin shape factor increases.

Optimization of a Reversed Trapezoidal Fin (역 사다리꼴 핀의 최적화)

  • Kang Hyung-Suk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.10 s.253
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    • pp.987-995
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    • 2006
  • A reversed trapezoidal fin with the fluid in the inside wall is analyzed and optimized in this study. As a fin base boundary condition, the heat transfer from inside wall fluid to the fin base is considered. The values of fin base temperature with the variations of inside wall fluid convection characteristic number and fin base length are listed. The heat transfer, fin effectiveness, fin length and fin base height are optimized as a function of fin base length, convection characteristic number ratio, fin shape factor and fin volume.

Malignant Transformation of Fibrous Dysplasia on Anterior Skull Base

  • Lee, Chul-Jae;Kim, Seong-Min
    • Journal of Korean Neurosurgical Society
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    • v.37 no.5
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    • pp.383-385
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    • 2005
  • Malignant transformation of fibrous dysplasia is a rare condition and the incidence is estimated at 0.4% for fibrous dysplasia and 4% for Albright's syndrome. The authors did not find a reported case of malignant change at skull base around the orbit in the literature. We experienced a case of fibrous dysplasia, in which neurologic symptoms were aggravated due to malignant change around the orbit, and report its favorable outcome obtained with total surgical removal.

Base Drag Characteristics with Exothermic Bleed/Jet (발열성 유출류와 제트를 고려한 기저부 저항 특성)

  • Shin J.R.;Choi J.Y.;Kim C.K.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.327-330
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    • 2006
  • Numerical simulations were carried out to investigate the base drag characteristics of a base bleed projectile with a central propulsive jet by considering the base homing process. Overall fluid dynamic process is modeled by Wavier-Stokes equations for reacting flows with two-equation $k-\omega$ SST turbulence closure. The combustion process is modeled by finite-rate chemistry with a given partially burned exit condition of the BBU (base-bleed unit). Besides the demonstrating the capability of the present CFD solver for the base drag and the interaction of the base flow with a rocket plume, present study gives an insight into the fluid dynamics and the combustion process of the hybrid-propulsion projectile.

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