• 대한가정학회지
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• 제29권1호
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• pp.13-25
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• 1991

We measured change of peripheral skin temperature and mean skin temperature when the upper arm and thigh are pressured in order to know the effect of skin pressure applied by clothing on blood circulation. After release from pressure, we observed also recovery condition. At the same time, we examined relation between pressure and a feeling of thightness. Three physiques of healthy females, namely slender, standard and plump, served as subjects. We used continuous restraint method with skin pressure applied by experimental fabric for 10 min. As a result of this experiment, we obtained following findings. 1. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under upper arm restraint. The peripheral and mean skin temperature decreased with the lapse of restraint time. A remarkable tendency observed according to the increase of restraint pressure. Recovery condition after release from pressure not yet recovered to original state, for all after a lapse of 10 min. 2. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under thigh restraint, especially different physique was remarkable among them. The peripheral skin temperature decreased or decreased. Recovery condition after release from pressure was the same upper arm. 3. Main factor affecting the evaluation of a feeling of tightness was restraint pressure. The value of pressure sensation made remarkable declined after a lapse of 10 min restraint time. Individual differences, however, were shown in pressure sensation.

• 복식
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• 제16권
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• pp.173-185
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• 1991

We measured change of peripheral skin temperature and mean skin temperature when the upper arm and thigh pressured in order to know the effect of skin pressure applied by clothing on blood circulation. After release from pressure, we observed also recovery condition. At the same time, we examined relation between pressure and a feeling of tightness. Three physiques of healthy females, namely slender, standard and plump, served as subjects. We used intermittent method with skin pressure applied by experimental fabric at l-minute intervals. Besides we made a comparative study with results according to different restraint method (continuous method and intermittent method). As a result of this experiment, we obtained following findings. 1. The significant difference was marked at the pressure, measuring time, physique and measuring region with change of skin temperature under upper arm and thigh restraint by intermittent method. The peripheral skin temperature decreased with the lapse of restraint time. A remarkable tendency observed according to the. increase of restraint pressure. Recovery condition after release from pressure not yet recovered to original state, for all after a lapse of 10 min. The mean skin temperature decreased with the lapse of restraint time in case of upper arm restraint, it was not an obvious tendency except 60mmHg under thigh restraint. 2. Main factor affecting the evaluation of a feeling of tightness was restraint pressure, when the upper arm and thigh restraint by intermittent method. The respondence rate of 'very tight' grew larger according to the increase of restraint pressure. The value of pressure sensation declined after restraint ten times as compared with one time, but there was difference according to restraint pressure. 3. We reexamined change of skin temperature and feeling of tightness by different restraint method(continuous method and intermittent method). The results were as follows. 1) The skin temperature decreased more greatly during skin pressure by continuous method than intermittent method, especially in the peripheral. Without different restraint method, the skin temperature of slender plysique decreased more greatly than that of plump physique. 2) The value of pressure sensation by intermittent method was highly on both sites of upper arm and thigh.

• 대한기계학회논문집A
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• 제30권9호
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• pp.1134-1141
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• 2006

This paper presents the model for evaluating restraint effect of pressure induced bending (PIB) on the circumferential through-wall crack opening displacement (COD), which considers plastic behavior of crack. This study performed three-dimensional elastic-plastic finite element (FE) analyses for different crack angle, restraint length, pipe geometry, stress level, and material conditions, and evaluated the influence of each parameter on the PIB restraint effect on COD. Based on these evaluations and additional perfectly-plastic FE analyses, a closed-form model to evaluate the restraint effect of PIB on the plastic crack opening of circumferential through-wall crack, was proposed as functions of crack angle, restraint length, radius to thickness ratio, axial stress corresponding to an internal pressure, and normalized COD evaluated from linear-elastic crack opening condition.

• Nuclear Engineering and Technology
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• 제39권1호
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• pp.75-84
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• 2007

This paper presents a closed-form model for evaluating the restraint effect of pressure induced bending on the opening of a circumferential through-wall crack, which is considered plastic deformation behavior. Three-dimensional finite element analyses with different crack lengths, restraint conditions, pipe geometries, magnitudes of internal pressure, and tensile properties were used to investigate the influence of each parameter on the pressure-induced bending restraint on the crack opening displacement. From these investigations, an analytical model based on elastic-perfectly plastic material was developed in terms of the crack length, symmetric restraint length, mean radius to thickness ratio, axial stress corresponding to the internal pressure, and normalized crack opening displacement evaluated from a linear-elastic crack opening condition. Finite element analyses results demonstrate that the proposed analytical model reliably estimated the restraint effect of pressure-induced bending on the plastic crack opening of a circumferential through-wall crack and properly reflected the dependence on each parameter within the range over which the analytical expression was derived.

• 한국안전학회지
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• 제19권4호
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• pp.8-13
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• 2004

The purpose of this paper is to investigate the welding residual stress distribution according to the constraint or non-constraint welding condition with titanium commonly using power station, aircraft, and ship. The measuring method of the residual stress was applied stress release rating method with strain gages and a potable strain meter. The x direction residual stress generally showed the tensile residual stress in case of res03int welding. On the other hand, the x direction residual stress under non-restraint welding were changed tensile stress into compressive stress on 15mm away from welding bead center. Also, the y direction residual stress generally showed the tensile residual stress in case of non-restraint welding and the y direction residual stress under restraint welding were changed tensile stress into compressive stress about 60mm away from welding bead center.

• 한국해양공학회지
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• 제13권3호통권33호
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• pp.49-56
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• 1999

Welding is a reliable process and is mainly adopted for fabricating heavy structures. Recently, transverse cracks in the weld metal is serious problem, and they affect cost, efficiency, safety and joint reliability for various welded structures. In this view of point, this study investigated the potential factors for weld metal transverse crack. The main results obtained are as follows; 1) The content of diffusible hydrogen in the commercial flux cored are welding wire was remarkable change by manufacturer. 2) The diffusible hydrogen content was thd main factor for weld metal transverse cracks. 3) Weld metal was immune to transverse cracking under the condition of low diffusible hydrogen content of high restraint condition. 4) The factors for weld metal transverse crack would be the content of diffusible hydrogen and restraint of weld joint.

• 콘크리트학회지
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• 제8권5호
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• pp.111-122
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• 1996

본 연구에서는 매스콘크리트의 외부구속도의 특성을 검토하기 위하여, 타설높이를 1.0m로 고정시킨 상태에서 타설블럭의 밑면길이와 타설높이와의 비(L/H), 하부 구속체의 탄성계수($E_r$) 등 매스콘크리트 구조물에서 특히 외부구속에 영향을 미치는 인자를 대상으로 parameter study를 실시하여 각 인자가 온도응력에 미치는 영향을 검토하고 각 인자간의 상호 영향도에 대해서도 검토하였다. 검토결과, 외부구속에 의해 발생하는 응력은 단면 높이방향으로 거의 직선분포를 이루고 있으며, L/H나 구속체 탄성계수의 크기에 따라서도 다르고 타설한 콘크리트의 강도발현에 따른 탄성계수의 증가 및 체적변화로 이해서 재령별로도 그 영향이 각각 다르다는 것을 알았다. 또한, 외부구속은 축방향구속과 휨방향구속으로 나누어 평가할 수 있으며, 외부구속이 약한 경우는 휨방향구속이 탁월하고, 외부구속이 강한 경우는 축방향구속이 탁월하다는 것을 알았다. 그리고타설높이 H를 1.0cm로 제한 시킨 경우에 ACI 207 위원회법으로 계산한 결과를 본 해석결과와 비교한 결과, ACI위원회법으 외부고속이 약한 경우에는 본 해석결과보다 큰 값으로 평가하고, 외부구속이 강한 경우에는 작게 평가하고 있음을 알았다.

• 한국해양공학회지
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• 제32권6호
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• pp.433-439
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• 2018

An investigation was conducted to determine whether the changes in the maneuvering forces and moments acting on a hull could be affected by changing the vertical center of gravity (VCG) of a tanker. The changes in the hydrodynamic forces and moment acting on a hull according to the restraint conditions of motion were examined using CFD for cases where the VCG was located at the design draught (100% of draught), under the design draught (75% of draught), and at half of the design draught (50% of draught). The following motion restraint conditions were selected: (1) fixed restraints for everything; (2) heave, pitch, and roll free restraint; and (3) heave and pitch free restraints. It was found that restraint condition (2) had the best agreement with the model experiment results. In addition, it was found that the hydrodynamic forces and moment acting on the hull with restraint condition (2) could be greatly affected in the model tests and CFD calculations by the various configurations for the vertical center of gravity of the hull. Finally, it was concluded that the location of the vertical center of gravity of the hull could be an important factor when more accurate hydrodynamic maneuvering forces and moment are estimated.

• Journal of Welding and Joining
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• 제34권4호
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• pp.28-33
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• 2016

The purpose of this study is to evaluate the redistribution of transverse residual stress in the multi-pass FCA butt weld of YP47 in the hatch coaming top plate of ultra large size containership under the tensile cyclic load. In order to do it, the configuration of modified H type specimen including restraint length was first designed to simulate the restraint condition of the butt weld in hatch coaming top plate. FE analysis procedure for evaluating the transverse residual stress was verified by comparing the calculated mean and surface residual stresses with the measured results in the test specimen. After that, the effect of the cyclic load on the redistribution of transverse residual stress was evaluated by comprehensive FEA. From the results, it was found that although the maximum transverse residual stress decreased with an increase in the applied maximum load, the effect of the cyclic load on the mean residual stress is small enough to be negligible. It is because the maximum stress of the ship corresponding to the probability of 10E-8 is less than 70% of yield stress of the weld.

• Journal of Oral Medicine and Pain
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• 제37권2호
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• pp.81-91
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• 2012

타액이 대부분의 구강 내 질환에 영향을 주는 것으로 알려져 있다. 반대로, 여러 전신적 조건이 타액의 흐름에 영향을 줄 수 있으며 이는 구강 건조증을 야기할 수 있는데, 특히 사회심리적 스트레스는 타액의 부족과 구강 건조증의 병인으로 큰 역할을 할 수 있다. 많은 연구에서 자율신경계 반응에 의한 스트레스의 타액선에의 거시적 효과에 중점을 두어왔다. 본 연구에서는 구속 스트레스 조건 하에서 백서(Rat) 이하선에서 clusterin의 변화를 관찰하였다. 연구를 위해, 10마리의 백서를 이용, 3그룹으로 구분하였다. 1) 그룹 1: 대조군으로 rat 2마리 2) 그룹 2 : 실험대조군으로 2마리를 두어 2시간 동안 restraint cone을 사용하여 구속스트레스를 부여 3)그룹 3 : 실험군으로 6마리를 두어 매일 2시간씩 restraint cone을 사용하여 구속 스트레스를 부여 백서는 스트레스 부여 후 즉시(그룹 2) 희생하거나 24, 48, 72 시간 후 희생하여 이하선을 절취하였다. Western blotting과 면역조직화학검사를 시행하여 다음과 같은 결과를 얻었다. 1. 백서의 이하선에서 clusterin이 약간 증가하였고 구속 스트레스 부여 직후 타액선관에서 명확하게 관찰되었다. 2. 백서의 이하선에서 clusterin은 구속 24시간, 48시간 후에 매우 감소되었으며, 타액선관에서도 소량 관찰되었다. 3. 백서의 이하선에서 clusterin은 구속 72시간 후 현저하게 증가되었으며, 역시 타액선관에 밀집하여 증가되었다.