• Title/Summary/Keyword: Tension

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Neonatal Tension Pneumopericardium (신생아 긴장성 심막 기종)

  • 손국희;김영삼;백완기;윤용한;김광호;성태정;전용훈;김정택
    • Journal of Chest Surgery
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    • v.37 no.5
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    • pp.464-466
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    • 2004
  • Neonatal tension pneumopericardium is a serious disease that requires prompt diagnosis and treatment. If untreated, it may lead to cardiac tamponade and death. We report a case of neonatal tension pneumopericardium which was successfully treated by open pericardial window operation with review of literatures.

Advanced Idealized Structural Units Considering Excessive Tension-Deformation Effects

  • Paik, Jeom-Kee
    • Journal of Hydrospace Technology
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    • v.1 no.1
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    • pp.125-145
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    • 1995
  • In this paper, three kinds of the existing idealized structural units, namely the idealized beam-column units the idealized unstiffened plate unit and the idealized stiffened plate unit are expanded to deal with the excessive tension-deformation effects. A simplified mechanical model far the stress-strain relationship of steel members under tensile load is suggested. The 1/3-scale hull model for a leander class frigate under sagging moment tested by Dow is analyzed, and it is shown that the excessive tension-deformation is a significant factor affecting the progressive collapse behavior, particularly in the post-collapse range.

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Investigation into Deformation of Three-Dimensional Microstructures via Surface Tension of a Rinsing Material During a Developing Process (현상공정에서 표면장력에 의한 극미세 3 차원 구조물의 변형거동 분석 및 저감방안에 관한 연구)

  • Park, Sang-Hu;Yang, Dong-Yol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.4
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    • pp.303-309
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    • 2008
  • Dense and fine polymer patterns often collapse, as they come into contact with each other at their protruding tips. Resist pattern collapse depends on the aspect ratio of patterns and the surface tension of rinsing materials. The pattern collapse is a very serious problem in microfabrication, because it is one of the factors which limit the device dimensions. The reasons for the pattern collapse are known as the surface tension of rinse liquid, centrifugal force and rinse liquid flow produced in the developing process. In this work, we tried to evaluate the pattern collapse of three-dimensional microstructures that were fabricated by two-photon induced photopolymerization, and showed the way how to reduce the deformation of microstructures.

Tension Crack and Active Earth Pressure by Using Coulomb이s Theory (Coulomb 이론을 이용한 인장균열 및 주동토압)

  • Jeong, Seong-Gyo;Lee, Man-Yeol;Kim, Mun-Gyu
    • Geotechnical Engineering
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    • v.12 no.6
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    • pp.101-114
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    • 1996
  • Even though the Coulomb's earth pressure theory has been mainly used in practice, the general equation does not exist yet, which is applicable to retaining wall backfilled by cohesive soils. Here, for gravity walls backfilled by cohesive soils, some equations have been derived by newly using the Coulomb's theory, for the cases oi drained and untrained analyses. and for the cases of neglecting and considering the tension crack, respectively. Both the active earth thrust and the depth of tension crack under different conditions were tabulated.

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A Study on Bubbly Lubrication of High-Speed proceeding Bearing Considering Live Surface Tension

  • Chun, S.-M.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.111-112
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    • 2002
  • The influence of aerated oil on a high-speed proceeding bearing is examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing including the live surface tension of aerated oil. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil aeration level, air bubble size and shaft speed. The results show that, if the live surface tension is considered, the effect of air bubbles on the bearing load capacity is reduced due to temperature engagement comparing with that under the condition of a constant surface tension.

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Evaluation of mechanical properties of Bi-2223/Ag HTS tapes (Bi-2223/Ag 고온초전도 선재의 기계적 특성 평가)

  • 하홍수;이동훈;양주생;최정규;윤진국;하동우;오상수;권영길
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.351-354
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    • 2002
  • In most of electrical applications using Bi-2223/Ag HTS tapes, bending and tension stresses are essentially applied to the tape. Therefore, the critical current of the Bi-2223/Ag tape is degraded by increasing the deformation stress, though brittle superconducting filaments are embedded in the reinforced Ag alloy sheath. It is needed to understand bending and tension properties of HTS tapes at room temperature and cryogen to make superconducting magnet, cable and etc. using Bi-2223/Ag HTS tapes. Actually, bending and tension stress applied to the tapes simultaneously, when winding the tapes on former for applications. In this study, the effect of mechanical deformations, bending and tension, on the critical current of Bi-2223/Ag tape was investigated.

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Nonlinear Analysis of High Strength Reinforced Concrete Members Considering the Tension Stiffening Model (인장강성 모델을 고려한 고강도 철근콘크리트 부재의 비선형 해석)

  • 홍창우;윤경구;김경진;박제선
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.479-482
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    • 1999
  • The tension stiffening effect, which means the maintaining a part of stiffness after cracking of concrete in tensile, exists at a reinforced concrete member because of the concrete softening and bonding stress between cracks. It is required to consider it for precise analysis and evaluation o structural behavior, due to the possibility of discrepancy between the actual behavior and the analysis without considering the tension stiffening effect. Making and adopting a tension stiffening model is the most simple and effective way for considering it at nonlinear analysis which indicated the estimation from models and experimental results were similar each others. The comparisons on RC beam were, also performed in order to analyzed the influence of concrete strength and steel ratio into the structural behavior. They indicated that the results from analysis estimated quite closely to the test results at low steel ratio, however, overestimated at high steel ratio. The overestimation increase linearly as concrete strength or steel ratio increased.

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Influence of Surface Tension on Pinhole Phenomenon of Earthen Ware Glazes (도기유의 표면장력이 Pinhole 현상에 미치는 영향)

  • 지응업;이경재
    • Journal of the Korean Ceramic Society
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    • v.13 no.3
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    • pp.3-12
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    • 1976
  • The corelation between surface tensions and surface appearances of SK O5a opaque glazes for earthen wares were investigated. The surface tension values were theoretically calculated by using Dietzel's factors of constituent oxides of glaze. The surface appearances of glazes, especially the pinhole phenomena were strongly effected by the surface tension values showing the following general tendencies: (1) In the range of 305±3 dynes/cm of surface tensions, glazes showed almost no pjnholes. (2) In the range of surface tensions less than 300 dynes/cm, the large numbers of small pinholes or eggshell textures were observed. (3) In the range of surface tensions higher than 310 dynes/cm, large and deep pinholes were observed. (4) The contact angles of glazes on the wall tile body substrate are in the good proportional agreement with the surface tension values calculated by Dietzel's factors.

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Dynamic Response Characteristics of Tension Leg Platforms in Waves (인장계류식 해양구조물의 동적응답 특성)

  • Lee, C.H.;Son, Y.K.
    • Journal of Power System Engineering
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    • v.2 no.2
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    • pp.81-86
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    • 1998
  • The dynamic response characteristics of Tension Leg Platforms(TLPs) in waves are examined for presenting the basic data for design of TLPs. The numerical approach is based on a combination of the three dimensional source distribution method and the dynamic response analysis method, in which the superstructure of TLP is assumed to be flexible instead of rigid. Restoring forces by hydrostatic pressure on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the motion and structural analysis. Numerical results are compared with the experimental ones, which are obtained in the literature, concerning the motion and tension responses of a TLP in waves. The results of comparison confirmed the validity of the proposed approach.

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Behavior Analysis of a Tension Leg Platform in Current and Waves (조류와 파랑 중의 인장계류식 해양구조물의 거동해석)

  • Lee, S.C.;Park, C.H.;Bae, S.Y.;Goo, J.S.
    • Journal of Power System Engineering
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    • v.15 no.1
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    • pp.64-71
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    • 2011
  • The Tension Leg Platform(TLP) is restrained from oscillating vertically by tethers(or tendons), which are vertical anchor lines tensioned by the platform buoyancy larger than the platform weight. Thus a TLP is a compliant structure which allows lateral movements of surge, sway, and yaw but restrains heave, pitch, roll. In this paper, the motions of a TLP in current and waves were investigated. Hydrodynamic forces and wave exciting forces acting on the TLP were evaluated using the three dimensional source distribution method. The motion responses and tension variations of the TLP were analyzed in the case of including current or not including one in regular waves and effects of current on the TLP were investigated.