• Title, Summary, Keyword: Melting temperature

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Experimental study on the melting characteristics of pellet fuel for a waste plastic firing boiler (열가소성 폐플라스틱 연소 보일러용 펠렛 연료의 용융특성 실험)

  • Lee, Sung-Soo;Kim, Hyouck-Ju;Choi, Gyu-Sung
    • 한국연소학회:학술대회논문집
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    • pp.189-193
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    • 2006
  • Experiments were performed to investigate the melting characteristics of pellet fuel made of LDPE and PP for a waste plastic firing boiler. Pellet fuel in a burner goes through conduction, convection and radiation transferred from flame in a furnace, and complex thermo/chemical processes. To figure out effects of ambient temperature and size of pellet on melting time pellets with a diameter from 5 mm to 40 mm were made to contact high temperature flue gas generated by a LNG firing pilot burner. Though melting processes of plastics include complicated heat transfer in a burner, parameters are limited to flue gas temperature and size for the simplicity in this study. From the results, melting times of LDPE and PP with a diameter of 5mm are 63 and 62 secs respectively at 600 $^{\circ}C$ while 677 and 583 sees respectively for a diameter of 40 mm. At $900^{\circ}C$, melting times of LDPE and PP with a diameter of 5mm are 21 and 24 sees respectively while 408 and 337 secs respectively for a diameter of 40 mm. It is found that melting time of LDPE is longer than that of PP, and melting times of both in general increase with diameter of pellets. It is thought melting is dependent mostly on melting temperature of plastic. It is expected melting times obtained from the study might be taken into account in designing a pellet firing burner for a boiler

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Experimental Study for Keeping a Melting Pool in a Waste Pyrolysis Melting Incinerator (폐기물 열분해 용융소각로의 용탕 유지를 위한 실험적 연구)

  • Kim, Bong-Keun;Park, Ju-Won;Yu, Tae-U;Yang, Won;Jeun, Keum-Ha
    • 한국연소학회:학술대회논문집
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    • pp.151-155
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    • 2006
  • The large amount of energy is consumed in a process for keeping the high temperature melting pool. For this reason, in addition to the wastes input to keep the high temperature melting pool, it is necessary for an auxiliary fuel and LOx to throw into the melting pool. So in this study, using a new melting furnace system, the experiments to keep the melting pool with minimal energy without throwing an auxiliary fuel and LOx was carried out. Also it is hoped that the results of the experiment will be available to analyze keeping a melting pool and behavior in a melting furnace.

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Derivation of Climate Zones and Melting Temperature Range for the Application of Phase Change Materials in Office Building (국내 업무시설의 상변화 물질 적용을 위한 기후존 분류 및 적정 용융온도 도출)

  • Kim, Kyung-Soo;Lee, Ki-Chul;Yoo, Dong-Chul;Park, Chang-Young
    • Journal of the Architectural Institute of Korea
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    • v.36 no.7
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    • pp.123-130
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    • 2020
  • This study is to derive the melting temperature range for applying phase change materials to buildings, and propose climate zones for each administrative region in Korea based on outdoor weather data variables affecting the melting temperature range of PCM, and analyze simulations. Through this, the melting temperature range of the PCM module attached to the building envelope was derived, and the results are as follows. (1) Factors influencing the melting temperature of PCM are surveyed by Heat Degree Hours, Cool Degree Hours, and solar insolation amount, and 14 climate zones were classified by selecting the ASHRAE classification method. (2) PCM increases heating energy consumption, but as cooling energy consumption decreases significantly, total energy consumption decreases. It is analyzed that the energy saving rate is reduced by 0.87 ~ 2.4%. (3) The proper melting temperature of PCM is a valid result, because it is analyzed that the phase change temperature is different according to the proposed climate zone. It is judged that classification by climate zone will be effective when constructing PCM design data for building applications.

An analysis of snow melting process for a study of defrosting phenomena (제상 현상 연구를 위한 눈 융해 과정 해석)

  • Lee, K.S;Ko, Y.W.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.1
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    • pp.38-47
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    • 1999
  • An improved one-dimensional modeling of snow melting was obtained by considering both the effect of heat capacity and the decreasing influence of porosity. Using the improved model, the effects of initial snow temperature, initial snow density and the heat flux on the snow melting were investigated. It is found that the drainage starting time is delayed and the drainage rate becomes smaller with lower initial snow temperature. ResuIts also show that the drainage starts at the same time when an initial snow density is over a certain value. Melting efficiency increases linearly with an increasing initial snow temperature. With increasing the initial density of the snow and the amount of heat supplied, the melting efficiency increases, then converges to a constant value.

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High Temperature Vaporization of the High Melting Point Oxides (고융점 산화물에 대한 고온 증발)

  • 이홍림
    • Journal of the Korean Ceramic Society
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    • v.15 no.2
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    • pp.72-78
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    • 1978
  • The vapor pressure of the high melting point oxides, MgO, $Cr_2O_3$, and $MgCr_2O_4$ were measured over the temperature range 1300 to 175$0^{\circ}C$ under vacuum <$10^{-5}$ torr by the Langmuir and the Knudsen method. The Langmuir vapor pressure was increased with elevating temperature and with increasing porosity of the specimen. The difference between the vapor preseures measured by the Langmuir and the Knudsen method was decreased with elevating temperature and the Langmuir vapor pressure finally reached the Knudsen vapor pressure at the melting point when extrapolated. The vapor pressure of other important oxides with high melting points, i.e., $Al_2O_3$, $ThO_2$, $Yb_2O_3$ and $Y_2O_3$ were cited from the references. The Langmuir and the Knudsen vapor pressure of these oxides also showed the same results, i.e., they showed the same value at their melting points.

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The Effects of Melting Temperature and Holding Time on Critical Characteristics of HTSC Fabricated by Melting Method (용융온도와 유지시간이 용융법으로 제작한 고온초전도체의 임계특성에 미치는 영향)

  • Lim, Sung-Hun;Han, Tae-Hee;Park, Kyung-Kuk;Yim, Seong-Woo;Cho, Dong-Eon;Han, Byoung-Sung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.2
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    • pp.154-161
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    • 1998
  • The effects of melting temperature and holding time on the critical current density($J_c$) of $YBa_2Cu_3O_x$ based superconducting bulk fabricated by MPMG process were investigated. The amount of the formed $Y_2BaCuO_5$ phases increased with the melting temperature. However, the value of critical current density was highest at 1120 $^{\circ}C$. With this proper melting temperature, the effect of holding time on the critical characteristics was also investigated. In the case of Ag addition, the volume of the formed $Y_2BaCuO_5$ phase when the amount of Ag addition was 10 wt% and 20 wt% was observed to be highest at 20 minute and 40 minute respectively. But in the specimen without Ag, volume of $Y_2BaCuO_5$ phase increased as the holding time increased. The proper melting temperature and the holding time obtained were 1120 $^{\circ}C$ and 20 minute. The long holding time was not effective for the $J_c$ improvement as well as the formation of $Y_2BaCuO_5$.

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Inter-comparison of temperature measurement capability using standard platinum resistance thermometers (표준백금저항온도계를 이용한 온도측정능력 상호비교)

  • Gam, K.S.;Kang, C.S.;Lee, Y.J.;Lee, K.B.;Kim, Y.G.;Park, S.N.
    • Journal of Sensor Science and Technology
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    • v.18 no.1
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    • pp.86-94
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    • 2009
  • Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

Measurement of Melting Temperatures of $UO_2,\;(U,Gd)O_2\;and\;(U,Er)O_2$ Fuels

  • Kang Ki Won;Yang Jae Ho;Kim Keon Sik;Kim Jong Hun;Lee Young Woo;Song Kun Woo
    • Nuclear Engineering and Technology
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    • v.36 no.1
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    • pp.104-111
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    • 2004
  • The melting temperatures of $UO_2,\;UO_2-6wt\%Gd_{2}O_3,\;UO_2-12wt\%Gd_{2}O_3,\;UO_2-2wt\%Er_{2}O_3,\;and\;UO_2-4wt\%Er_{2}O_3$ fuels were measured. Fuel materials were loaded in a tungsten capsule of which shape met the black body condition. The melting temperature was measured by the thermal arrest method during heating of the capsule in an induction furnace. The measured melting temperature of $UO_2$ fuel was $2815{\pm}20^{\circ}C$. The solidus and liquidus temperatures of $UO_2-Gd_{2}O_3\;and\;UO_2-Er_{2}O_3$ had also been measured, and it was observed that the solidus temperatures of them were lower than the liquidus temperature by $15{\sim}25^{\circ}C$. Measured melting temperatures of $UO_2,\;UO_2-Gd_{2}O_3\;and\;UO_2-Er_{2}O_3$ fuels were as follows:

Effect of Glass Melting Conditions on the Structural Properties of Chalcogenide Glasses for Infrared Optics (적외선 광학렌즈용 칼코게나이드 유리의 Glass melting 조건에 따른 특성 변화)

  • Park, Heung-Su;Lee, Hyun-Yong;Cha, Du-Hwan;Kim, Hye-Jeong;Kim, Jeong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.167-167
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    • 2010
  • Ge-Sb-Se계 칼코게나이드 유리의 Melting 조건변화에 따른 특성변화를 연구하였다. Glass melting 조건(homogenization-temperature, homogenization-time, annealing) 에 따라 제작된 칼코게나이드 유리 bulk를 FT-IR, XRD, SEM 등의 분석장비를 이용하여 특성을 분석하였다. Homogenization temperature가 높을수록 석영관 급냉 시 발생되는 mechanical stress와 내부응력차로 인해 칼코게나이드 유리 깨짐현상이 증가하였으며 조성비와 melting 조건에 따라 XRD분석에서 확인되지 않는 미소결정이 SEM 분석결과 관찰되었다. 본 연구를 통해 칼코게나이드 유리의 melting 조건에 따른 경향성을 확인할 수 있었다.

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Heat Processing and Dyeing Properties of Fabrics by Using Composite Fancy Yarn Containing Low Melting PET Yarn (저온융착 폴리에스테르사 함유 팬시사 직물의 열처리 특성 및 염색성)

  • Sung, Woo Kyung
    • Fashion & Textile Research Journal
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    • v.14 no.6
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    • pp.1024-1031
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    • 2012
  • The thermal bonding PET fabrics were produced through high temperature steaming (HTS) of low melting PET yarn as warp and composite fancy yarn containing low melting PET yarn as weft. The low melting PET yarn of sheath-core structure consisted of a regular PET in core portion and low melting PET in sheath portion. The composite fancy yarn consisted of regular PET yarn as inner part and effect part and low melting PET yarn as binding part. This study was carried out to investigate the melting behavior of thermal bonded PET fabric, the effect of HTS on the thermal bonding, mechanical properties, and dyeing properties. The melting peak of low melting PET yarn showed two melting peaks caused by sheath-core structure. Almost the entire thermal bonding of the fancy PET fabrics containing low melting PET yarn has formed at $200^{\circ}C{\times}3min$ of HTS. The tensile strength in warp and weft direction of the fancy PET fabrics slightly decreased as temperature of HTS increased. The total K/S value of the fancy PET fabrics decreased slightly to $180^{\circ}C{\times}3min$ of HTS, while increased slightly above $200^{\circ}C{\times}3min$ of HTS. The changes in the hue angle ($H^{\circ}$) of the thermal bonded fancy PET fabrics dyed with disperse dyes hardly ever happened.