• Title/Summary/Keyword: thermal change

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Analysis of Amur Cork Tree Extract and Dyed Silk upon Thermal Degradation Treatment (황벽 추출염료와 염직물의 열적 퇴화 거동 연구)

  • Ahn, Cheun-Soon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.10
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    • pp.1228-1241
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    • 2011
  • This research compares the change in berberine content in liquid dye and the color and dye uptake of amur cork tree dyed silk upon thermal degradation treatment. Thermal degradation of amur cork tree extract and liquid dye of standard berberine was carried out at room temperature, $4^{\circ}C$ refrigeration, and $100^{\circ}C$ oven conditions for 0-192 hours. Amur cork tree dyed silk was treated in a $100^{\circ}C$ oven for 0-240 hours. The berberine content in liquid dye was measured by the relative abundance of the berberine peak in the HPLC-MS chromatograms. The color and dye uptake of dyed silk was measured using K/S value and colorimetric data. The berberine content in standard berberine dye was 2.4 times that of the amur cork tree extract. A similar result was observed between the K/S value of standard berberine dyed silk and that of amur cork tree dyed silk. The berberine dyed silk showed the highest dye uptake after 120 hours in a $100^{\circ}C$ oven. This result was similar to the change in a berberine content in liquid dye in a $100^{\circ}C$ oven treatment. The change of the K/S value of amur cork tree dyed silk and berberine content of amur cork tree extract was similar up to 24 hours. The result suggests that there is a direct relationship between the color change of amur cork tree dyed silk and the berberine content in amur cork tree dye.

Effects of the mosture and thermal annealing on CLBO crystal

  • Mori, Yusuke;Sasaki, Takatomo
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1997.06a
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    • pp.125-129
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    • 1997
  • The effects of the moisture and thermal annealing on CLBO crystal have been investigated. CLBO has hydrated at high humidity condition, resulting in 5B$_2$O$_3$$.$Cs$_2$O$.$8H$_2$O. The surface hydration seems to induce the cracking and the refractive index change in CLBO. The thermal annealing is effective to restore the changed index.

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A Numerical Simulation of Regenerative Cooling Heat Transfer for the Rocket Engine (로켓엔진의 재생 냉각 열전달 해석)

  • 전종국;박승오
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.127-130
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    • 2003
  • This paper presents the numerical thermal analysis for regeneratively cooled rocket thrust chambers. An integrated numerical model incorporates computational fluid dynamics for the hot-gas thermal environment, and thermal analysis for the liner and coolant channels. The flow and temperature fields in rocket thrust chambers is assumed to be axisymmetric steady state which is presumed to the combustion liner. The heat flux computed from nozzle flow is used to predict the temperature distribution of the combustion liner. As a result, we present the wall temperature of combustion liner and the temperature change of coolant.

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The thermal & hydraulic analysis of the cooling passage for HTS power cable (초전도케이블 냉각유로의 열 및 유동 특성 해석)

  • 홍용주;염한길;김효봉;고득용
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.167-170
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    • 2003
  • The thermal and hydraulic characteristics of the cooling passage for HTS power cable should be carefully investigated to get the highly reliable and economic operation. In this study, the pressure drop and temperature change of the coolant flowing the corrugated passage was estimated using the simple one-dimensional approach, and the temperature distribution in the radial direction was calculated. The results show the dependency of the mass flow rate, thermal conductivities on the cooling performance of the HTS cable.

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The Fire induced Thermal Stress Analysis of PC Box Bridge (PC Box교량의 화재에 대한 열응력해석)

  • 최창근;이계희;최인혁;김일곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.10a
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    • pp.125-132
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    • 1998
  • In this study the fire, due to overturning of oil tanker on the bridge induced heat transfer analysis and thermal stress analysis are carried out. The results of analysis for fire history of 1 hour present very large thermal gradient near the surface. However, the temperature increase of tendon & rebar that is the main resistant member of bridge is not sufficient to change material properties. The Von-Mises yield criteria is used to calculate the depth of delamination, The depth of delamination is about 4cm at center of fire and this value is close to measured value.

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Heat Transfer Analysis of Freezing Processes Including Thermal Resistance of Mold(I) - One - dimensional Analysis of Saturated Liquid - (용기를 고려한 응고과정의 열전달 해석(I) - 포화액의 일차원 해석 -)

  • Yoo, Jai Suk
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.4
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    • pp.377-381
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    • 1988
  • Effects of thermal resistance of mold during freezing processes have been investigated. Saturated liquid is chosen to present one-dimensional quasi-steady solution and this solution is compared with numerical solutions. Front tracking finite element method has been applied for the numerical solutions. Results show that mold should be considered as well as phase change material except the cases when the very thin mold with relatively high thermal conductivity is used.

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Enhancement of Convective Heat Transfer by Using a Micro-Encapsulated Phase-Change-Material Slurry (피복된 미립 상변화물질 슬러리를 이용한 대류 열전달의 향상에 관한 연구)

  • Jung, Dong-Ju;Choi, Eun-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.9
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    • pp.1277-1284
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    • 2000
  • To enhance heat transfer characteristics of water, micro-encapsulated octadecane of about $10{\mu}m$ diameter was added to water. Viscosity of the slurry was measured by using a capillary tube viscometer. The measured viscosity decreased as the temperature of the slurry increased, and it increased as the fraction of the capsules in the slurry increased. Thermal characteristics of the octadecane were studied by using a differential scanning calorimeter. The melting temperature and the melting energy of the octadecane were found to be $28.6^{\circ}$ and 34.4kcal/kg, respectively. The convective heat transfer characteristics of the slurry were investigated in a flow loop with a constant heat flux test section. Friction factor of the slurry flow was found to be similar to the expected curve by Petukhov. The Nusselt number of the slurry flow was highest when the octadecane melted. Effective thermal capacity of the 14.2% slurry was found to have 1.67 times of the thermal capacity of water.

Physical Properties of Microencapsulated Phase Change Material Slurries (미립잠열슬러리의 물성에 관한 실험적 연구)

  • 이효진;홍재창;이재구
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.9
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    • pp.860-869
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    • 2000
  • The thermal conductivity and density of slurries entrained with the particles of Micro-PCM are measured with respect to its temperatures as well as concentrations. For the thermal conductivity of slurries, a device made from P.A. Hilton (Model No. H470) is adopted. There is a well-scaled 0.3 mm gap between shells into which the slurry is injected. The temperatures of the slurry are changed to $5~25^{\circ}C$ , for which it is controled by the supplied voltage and cooling water circulated around the outer shell. The concentrations of Micro-PCM slurries are varied from 5 wt% to 50 wt%. Some general equations such as Maxwell's equation, are evaluated for their applicability with Micro-PCM slurry. As a result, it happens to be some 20% discrepancy between the experiment and the applied equations. The density measurements of Micro-PCM slurry to its temperature and concentration are peformed by hydrometer. For the experiment, tetradecane encapsulated slurry (($t_m≒6^{\circ}C$) and a mixed wax ($t_m≒50^{\circ}C$) are tested. The temperature changes of tetradecane are applied for $0^{\circ}C\;to\;$20^{\circ}C$and a mixed wax for $20^{\circ}C\;to\;$60^{\circ}C$ and its concentrations are changed from 5 wt% to 30 wt%. The results are compared with a general equation and the referenced data. For the conclusion, the experimental result and a general equation are well agreed.

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Effects of Somatotype Characteristics on Body Temperature Control Reaction & Thermal Sensation (체형특성(體型特性)이 체온조절반응(體溫調節反應) 및 온열쾌적감(溫熱快適感)에 미치는 영향(影響))

  • Shim, Boo-Ja;Yoo, Hyun
    • Journal of Fashion Business
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    • v.7 no.1
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    • pp.27-37
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    • 2003
  • This study is the first part of the research to reveal the effects of somatotype characteristics on body temperature control reaction as well as thermal sensation. Nine healthy female collegians (classified into 3 body types of thin, normal, and obese according to Rohrer index) living in Busan were chosen as the subjects. The following are the results: Significant differences of skin temperature appeared in the parts of epigastrium (thin/normal>obese), anterior forearm (normal>thin/obese), and anterior leg (obese > thin/normal) as well as mean skin temperature. Mean skin temperature temporarily dropped owing to the exercise but tended to recover as time went by. Skin temperature of normal/thin shows higher than obese type. The change of skin temperature was noticed in the order of forehead > epigastrium > anterior forearm > anterior leg > anterior thigh (obese type) ; epigastrium > forehead > anterior forearm > anterior thigh > anterior leg (normal type) ; epigastrium > forehead > anterior forearm > anterior thigh > anterior leg (thin type, before and after exercise); epigastrium > forehead > anterior forearm > anterior leg > anterior thigh (thin type, during exercise). Significant differences were shown in the temperature change inside clothes according to somatotypes. No significant differences were revealed in thermal sensation, moisture sensation, and comfortable sensation according to body types and time.

The Change of Crystal Structure and Physical Properties of Partially Oriented Polyester Yarn(POY) on the Draw Ratio and Heat Setting Temperature (연신비와 열고정 온도에 따른 Partially Oriented Polyester Yarn(POY)의 구조변화와 물성)

  • 박명수;윤종호
    • Textile Coloration and Finishing
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    • v.12 no.2
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    • pp.103-110
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    • 2000
  • To examine the physical properties of POY through the microstructure control, the crystal structure such as the crystallinity, the crystallite size, the orientation, the shrinkage, the tensile properties, and the thermal stress of POY(80/48, SD) were examined at different draw ratios and annealing temperatures. From the examination following conclusions were obtained : 1. The crystallinity was more effected by the heat setting temperature than by the draw ratio. The increasing rate was greatest at the heat setting temperature range of $170~190^\circ{C}$. 2. The crystallite size perpendicular to the fiber axis was more effected by the annealing temperature at lower draw ratios. On the other hand, the crystal and amorphous orientations were more effected by the heat setting at higher draw ratios. 3. The boiling shrinkage did not change significantly, but the total shrinkage showed 13% at the draw ratio 1.9 and the heat setting temperature $170^\circ{C}$. 4. The maximum thermal stress increased with increasing the draw ratio and decreasing the heat setting temperature in the temperature range of $170~210^\circ{C}$. At the draw ratio 1.9 and the heat setting temperature $170^\circ{C}$, the maximum thermal stress found was 1.1gf/d. 5. In the heat setting temperature above $170^\circ{C}$ after the drawing, the crystallinity, the crystallite size, the orientation, and the strength increased with increasing temperature, but the shrinkage and the maximum thermal stress decreased with increasing temperature.

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