• Title/Summary/Keyword: shear heating

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A STUDY ON THE ADHESION OF A SOFT LINER CONTAINING 4-META TO THE BASE METAL ALLOY AND ITS VISCOELASTIC PROPERTY

  • Park Hyun-Joo;Kim Chang-Whe;Kim Yung-Soo
    • The Journal of Korean Academy of Prosthodontics
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    • v.41 no.6
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    • pp.732-746
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    • 2003
  • Statement of problem. Soft lining materials, also referred to as tissue conditioning materials, tissue heating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. Purpose. The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. Material and Methods. This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the Relation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL.,USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint desist which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the $20{\times}20mm$ transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/ TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. Conclusion. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.

Effect of Cooking Methods with Various Heating Apparatus on the Quality Characteristics of Chicken (가열기구에 따른 조리방법이 닭고기의 품질특성에 미치는 영향)

  • Jeon, Ki-Hong;Kwon, Ki-Hyun;Kim, Eun-Mi;Kim, Young-Boong;Sohn, Dong-In;Choi, Jin-Young
    • Culinary science and hospitality research
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    • v.20 no.3
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    • pp.201-213
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    • 2014
  • This study showed the quality characteristics of chicken breast meat(CB) and leg meat(CL) with various kinds of existing cooking methods and double layer pan filled with Phase Change Materials(PCM) heating. Steaming resulted the highest moisture contents of 63.9% and 62.1% each in CB and CL. Also, steaming showed the lowest with 1.3% and 8.6% of crude fat in CB and CL(p<0.05) respectively. Crude protein content of CB in charcoal heating and grilling of CL had the highest values of 37.9% and 30.5% each. In the test of crude ash, grilling showed the highest with 2.4% in CB(p<0.05) and oven heating and charcoal heating was the highest with 1.3% in CL(p<0.05). In the test of cooking loss, charcoal heating showed much higher with 33.52% and 41.16% in CB and CL each than the other cooking treatments. And in case of shear force test, $5.93kg/cm^2$ in CB and $6.80kg/cm^2$ in CL were the highest scores in grilling. In the test of color, L value of CB prepared by steaming showed the highest scores of 78.31(p<0.05) while CL by oven heating was the highest of 10.00 in a value. In the overall acceptability test of 9 point-scale sensory evaluation, CB prepared by charcoal heating showed the highest score of 7.25 points in boiling, but the lowest score of 6.00 points in steaming(p<0.05). CL by charcoal heating resulted the highest score of 7.71 points but had no significant difference.

NON-COPLANAR MAGNETIC RECONNECTION AS A MAGNETIC TWIST ORIGIN

  • CHAE JONGCHUL
    • Journal of The Korean Astronomical Society
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    • v.32 no.2
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    • pp.137-147
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    • 1999
  • Recent studies show the importance of understanding three-dimensional magnetic reconnect ion on the solar surface. For this purpose, I consider non-coplanar magnetic reconnection, a simple case of three-dimensional reconnect ion driven by a collision of two straight flux tubes which are not on the same plane initially. The relative angle e between the two tubes characterizes such reconnection, and can be regarded as a measure of magnetic shear. The observable characteristics of non-coplanar reconnection are compared between the two cases of small and large angles. An important feature of the non-coplanar reconnect ion is that magnetic twist can be produced via the re-ordering of field lines. This is a consequence of the conversion of mutual helicity into self helicities by reconnection. It is shown that the principle of energy conservation when combined with the production of magnetic twist puts a low limit on the relative angle between two flux tubes for reconnect ion to occur. I provide several observations supporting the magnetic twist generation by reconnection, and discuss its physical implications for the origin of magnetic twist on the solar surface and the problem of coronal heating.

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Thermal Stability Analysis of 2-D Spacecraft Appendage (위성체 2-D 구조물의 열 안정성 해석)

  • 윤일성;송오섭;김규선
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.99-104
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    • 2001
  • Thermally induced vibration response of solar array is investigated. The solar array model consists of composite thin walled beam and solar blanket, spreader bar. The composite thin walled beam incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. The solar blanket is a membrane subjected to uniform tension in the z direction. The spreader bar is a rigid member. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated. A stability criterion given in parameters for establishes the conditions for thermal flutter.

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Hydrodynamic Analysis of Piston Rings (피스톤 링의 유체 윤활 해석)

  • 김재현;최상민;김경웅
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.167-172
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    • 1998
  • An algorithm of Thermal-elastohydrodynamic lubrication analysis for the piston ring is developed. This algorithm contains cavitation boundary condition so it automatically satisfies conservation of mass. 1-D Reynolds equation and 2-D energy equation are solved simultaneously by using Gauss-Jordan method and Newton-Raphson method. Minimum film thickness and friction force are calculated for 1 cycle. There is little difference between the results caculated by isothermal rigid and EHL analysis in entire cycle. In the results of THL, shear heating effect and temperature boundary condition affect the minimum film thickness and friction force prediction. The minimum film thickness and the friction force calculated by THL are lower than those caculated using isothermal assumption.

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Matching inviscid and boundary layer method for incompressible and compressible flows (비압축성과 압축성 유동에 있어서 비점성 유동과 경계층 유동의 결합)

  • Sohn, Chang-Hyun;Moon, Su-Yeon;Lee, Jeong-Yun
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1966-1971
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    • 2003
  • Matching inviscid and boundary layer methods are developed for hypersonic flow with thick boundray layer. The new equations match all the boundary layer properties with a variation in the inviscid solution near the edge, except for the normal velocity. Computational comparison are performed for incompressible and compressible flows over a flat plate. Results from the present method are compared with Navier-Stokes solutions. The present results are in good agreement with Navier-Stokes solutions. They show that the new technique can provide improved heating rates and skin friction predictions for preliminary design of vehicles where shear layers and entropy layer swallowing are important.

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Study on High Temperature Processing of Ti-10Ta-10Nb Alloys (Ti-10Ta-10Nb 합금의 고온 가공 특성에 관한 연구)

  • 반재삼;이경원;유영선;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.418-421
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    • 2003
  • Specimens of Ti-10Ta-10Nb have been hot upset forged after heating to either the $\alpha$+$\beta$ and $\beta$-phase field. The variety temperatures (At 650, 700, 750, 800, 85$0^{\circ}C$) and strain rates (At 0.001, 0.01. 0.1, 1, 10 $s^{-1}$ ) were used. On the basis of flow stress data obtained as a function of temperature and strain rate in compression, a processing map for hot working has been developed. At strain rates lower than about 0.1 $s^{-1}$ and almost temperatures, processing efficiency exhibited high, but at 0.001 $s^{-l}$, and temperature 80$0^{\circ}C$, low because the Shear band has occurred. On the basis of the processing map, the optimum processing routes available for hot working of this material are outlined.d.

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Thermal Stability Analysis of Flexible Beam Spacecraft Appendage (위성체 유연 보 구조물의 열 안정성 해석)

  • 윤일성;송오섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.399-406
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    • 2001
  • Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

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Thermally Induced Vibration Analysis of Flexible Spacecraft Appendages (위성체 유연구조물의 진동 해석)

  • Yoon, Il-Soung;Kim, Gu-Sun;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1216-1221
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    • 2000
  • Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, 'rotary inertia' and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

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Boundary Layer Analysis in a Hypersonic Flow Field (극초음속 유동장의 경계층 해석)

  • Sohn Chang-Hyun;Choi Seung;Moon Su-Yuon;Kim Jae-Yung;Lee Yul-Hwa
    • Journal of the Korea Institute of Military Science and Technology
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    • v.7 no.3 s.18
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    • pp.165-173
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    • 2004
  • Matching inviscid and boundary layer methods are developed for analysis of hypersonic flow with thick boundary layer. The new equations match all the boundary layer properties with a variation in the inviscid solution near the edge, except for the normal velocity. Computational comparison are peformed for incompressible and compressible flows over a flat plate. Results from the present method are compared with Wavier-Stokes solutions. The present results are in good agreement with Wavier-Stokes solutions. They show that the new technique can provide improved predictions of heating rates and skin friction predictions for preliminary design of vehicles where shear layers and entropy layer swallowing are importantfor for preliminary design.