• Title/Summary/Keyword: melting time

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Finishing of Interior Fabric Using Soluble Micro-fiber and low melting Yarn (용출형 극세사와 저온 융착사를 이용한 인테리어 직물의 가공)

  • Ahn, Young-Moo
    • Journal of Fashion Business
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    • v.13 no.2
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    • pp.78-86
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    • 2009
  • When scouring and contraction finishing at 90C using Relaxer or Rotary Washer contraction and weight loss ratio in warp and weft directions were excellent. Also surface state of fabric after drying or sanding treatment was excellent without crease. Low melting polyester fabric showed a complete melting bond by heat setting(P/S) at above 160C. The alkali hydrolysis reaction of polyester showed the breakpoint in the weight loss behavior test, polyester yarn showed a breakpoint ranging from 25% to 28%. This is due to the difference of the hydrolysis rate between regular polyester and soluble polyester. Initially the soluble polyester was eluted and micro-fibrillized 5 times faster than a regular polyester. At a later time, a regular polyester was reduced weight to impart a proper flexibility and drape property to the fabric. As a result of surface sanding finishing, the surface of interior fabric showed a surface state most stabilized when using Mesh No. 220 in mono 0.2d after elution finishing. When the rotation direction of sanding roller was pro-, pro-, pro-, and retro-direction, a directional effect of tuft was not shown, a writing effect as suede was exhibited and a surface state was even. Sublimation fastness was 3-4 class for polyester and 2-4 class for nylon. Light fastness 3-4 class after lapse of 100 hours and 2-4 class after lapse of 160 hours. Abrasion fastness was 3-4 class on wet and 4-5 class on dry Laundry fastness was 2-4 class. As such, the abrasion fastness is slightly reduced upon wetting and the use thereof for interior is excellent, whereas laundry fastness is slightly lowered.

Preparation and Thermal Characteristics of Hexadecane/xGnP Shape-stabilized Phase Change Material for Thermal Storage Building Materials (축열건축자재 적용을 위한 Hexadecane/xGnP SSPCM 제조 및 열적특성)

  • Kim, Sug-Hwan;Jeong, Su-Gwang;Lim, Jae-Han;Kim, Su-Min
    • Journal of the Korean Solar Energy Society
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    • v.33 no.1
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    • pp.73-78
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    • 2013
  • Hexadecane and exfoliated graphite nanoplate (xGnP)composite was prepared as a shape-stabilized phase change material (SSPCM) in a vacuum to develope thermal energy storage. The Hexadecane as an organic phase change material (PCM) is very stable against phase separation of PCM and has a melting point at 18C that is under the thermally comfortable temperature range in buildings. The xGnP is a porous carbon nanotube material with high thermal conductivity. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR)were used to confirm the chemical and physical stability of Hexadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter(DSC) and Thermogravimetric analysis (TGA). The specific heat of Hexadecane/xGnPSSPCM was 10.0J/gK at 21.8C. The melting temperature range of melting and freezing were found to be 1625C and 1712C. At this time, the laten heats of melting and freezing were 96.4J/g and 94.8J/g. The Hexadecane was impregnated into xGnP as much about 48.8% of Hexadecane/xGnP SSPCM's mass fraction.

Numerical Analysis for Thermal Design of Electronic Equipment Using Phase Change Material (상변화 물질을 이용한 전자 장비 방열 설계의 수치 해석적 연구)

  • Lee, Dong Kyun;Lee, Won Hee;Park, Sung Woo;Kang, Sung Wook;Cho, Ji Hyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.4
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    • pp.285-291
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    • 2017
  • In this study, a case analysis for thermal design of electronic equipment using a phase change material(PCM) was performed numerically using ANSYS Fluent. Experiments were conducted to find the temperature increase(ΔTm), melting temperature(Tm), and volume expansion of the PCM under the melting process. To verify the accuracy of the Fluent solver model, Tm, ΔTm, and the melting time were compared with experimental results. To simulate the temperature stagnation phenomenon under the melting process, the equivalent specific heat method was applied to calculate the thermal properties of the PCM in the solver model. To determine the thermal stability of electronic equipment, we paid special attention to finding a thermal design for the PCM using fins. Further, an additional numerical analysis is currently underway to find an optimum design.

Fabrication of Porous Titanium Parts by Direct Laser Melting of Ti-TiH2 Mixing Powder (Ti-TiH2 혼합 분말의 레이저 직접 용융 공정을 이용한 다공성 티타 늄 부품 제조 연구)

  • Yun, H.J.;Seo, D.M.;Woo, Y.Y.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.28 no.1
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    • pp.21-26
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    • 2019
  • Direct Laser Melting (DLM) of TixTiH2 (mixing ratio x = 2, 5, 10 wt.%) blended powder is characterized by producing porous titanium parts. When a high energy laser is irradiated on a TiTiH2 blended powder, hydrogen gas (H2) is produced by the accompanying decomposition of the TiH2 powder, and acts as a pore-forming and activator. The hydrogen gas trapped in a rapidly solidified molten pool, which generates porosity in the deposited layer. In this study, the effects of a TiH2 mixing ratio and the associated processing parameters on the development of a porous titanium were investigated. It was determined that as the content of TiH2 increases, the resulting porosity density also increases, due to the increase of H2 produced by TiH2. Also, porosity increases as the scan speed increases. As fast solidified melting pools do not provide enough time for H2 to escape, the faster the scan speed, the more the resulting H2 is captured by the process. The results of this study show that the mixing ratio (x) and laser machining parameters can be adjusted to actively generate and control the porosity of the DLM parts.

Manufacturing and Properties of Bi-Sn Impregnated Wood Composites of Juglans nigra (북미산 흑호두나무 Bi-Sn 용융합금 복합체의 제조와 특성)

  • Kang, Seog-Goo;Park, Kye-Shin;Lee, Ho;Seo, In-Soo;Lee, Jong-Shin;Lee, Hwa-Hyoung
    • Journal of the Korea Furniture Society
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    • v.22 no.1
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    • pp.54-62
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    • 2011
  • The metalized wood composites with natural grain of imported Juglans nigra, which was impregnated with low melting alloy were manufactured and evaluated in this study. And the proper manufacturing conditions was also investigated in this study. The low melting alloy with bismuth (Bi) and tin (Sn) which are harmless to humans, was applied to this new composites. The composites showed not only no defects of discoloration, delamination, swelling, and cracking, because of high dimensional stability and low thickness swelling, but also much improved performance such as high bending strength, high hardness, abrasion resistance, high thermal conductivity as floor materials. This study also suggested the proper impregnating condition, such as 10 minutes of the preliminary vacuum time, 186C of the heating temperature and 10 minutes of the maintaining pressure time at the pressure of 30kgf/cm2. This metalized wood composites showed 7 times higher density than control, great increase in bending strength from 131.8N/mm2 to 192.3N/mm2, and great increase in hardness from 18.2N/mm2 to 90.4N/mm2. The composites demonstrated not only high emissivity of 91%, high shilding effectiveness of 92.59∼99.99%, high fire resistance but also great decrease in abrasion depth, water absorption and thickness swelling.

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Application of Graphene Platelets on Electronic Controlled Thermostat of TGDI Engine for Improving Thermal Sensitivity (TGDI엔진용 전자식 수온조절기의 감온성능 향상을 위한 그래핀 소재의 적용)

  • Kim, SeoKyu;Kim, YongJeong;Joung, Heehwa;Jeon, Wonil;Jeong, Jinwoo;Jeong, SooJin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.1
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    • pp.66-73
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    • 2017
  • In this work, graphene platelets were introduced into wax in an automotive electronic controlled thermostat for the purpose of enhancing its thermal-conductive property and improving response performance. Graphene content ranging from 10 % to 20% was added into and mixed with the wax to investigate the effect of graphene amounts on the performance of an automotive electronic controlled thermostat in terms of response time, hysteresis and melting temperature. The experimental results revealed that graphene in wax contributed to a reduction in the response time and hysteresis of an automotive electronic controlled thermostat. As a consequence, important improvement in thermal sensitivity, full lift, melting temperature and hysteresis were obtained. The thermal response of wax with graphene content of 20 % was improved by 25 %, as compared to that of wax with Cu content of 20 %. Hysteresis of wax with graphene was reduced by 0.6C as compared to that of wax with Cu content. The melting temperature of wax is lowered and hysteresis is also improved with increased graphene content of wax in an electronic controlled thermostat. We hope that this study can help further the transition of nano-fluid technology from small-scale research laboratories to industrial application in the automotive sector.

Effect of Gelation Condition on Physical Properties of Yellowfin Sole Gelatin Prepared by Ethanol Fractional Precipitation (에탄올처리 각시가자미껍질 젤라틴의 물리적 특성에 대한 겔화조건의 영향)

  • Kim, Jin-Soo;Cho, Soon-Yeong;Ha, Jin-Hwan;Lee, Eung-Ho
    • Korean Journal of Food Science and Technology
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    • v.27 no.4
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    • pp.483-486
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    • 1995
  • With a view to increase utility of ethanol fractionated fish skin gelatin as a food source, the effect of gelation condition on physical properties of the gelatin was investigated. The physical properties of gelatins treated with or without ethanol were improved with a concentration of gelatin increased. The properties such as gel strength, melting point and gelling point of 10% gelatin sol or gel were reached to maximum at pH 6.0 in ethanol treated gelatin and pH 5.0 in non treated one, respectively. Gel strength and melting point of both gelatin gels chilled for long time at low temperature were superior to those of both gelatin gels chilled for short time at high temperature. Gel strength, melting point and gelling point of ethanol treated gelatin gel or sol prepared under optimized gelation conditioning were superior to those of non treated one.

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Optimization of an Injection Molding Process for Polycarbonate Car Switch Buttons Using the Taguchi Method (실험계획법에 의한 폴리카보네이트 차량 스위치 버튼의 사출성형공정 최적화)

  • Kim, Cheol;Park, Jaewoo
    • Composites Research
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    • v.29 no.1
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    • pp.7-15
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    • 2016
  • The quality of polymeric automotive parts depends highly on an injection molding process, which causes various defects, such as warpage, sink marks, weld lines, shrinkage, residual stress, etc. This study is to determine the optimum processing parameters, such as packing pressure, mold temperature, melting temperature, and packing time for the manufacture of polycarbonate buttons in cars on the basis of FEM, the Taguchi method, and analysis of variance (ANOVA). As a result, the optimum processing parameters of buttons made of polycarbonate material were obtained as follows: 140 MPa of packing pressure, 105C of mold temperature, 292.5C of melting temperature and 1 second of packing time. A gain of S/N (signal to noise) ratio, 10.2, was obtained with the optimum values. Moreover, the melting temperature was found to be the most significant factor followed by the mold temperature.

A study on the growth mechanism of rutile single crystal by skull melting method and conditions of RF generator (스컬용융법에 의한 루틸 단결정 성장메커니즘과 RE generator 조건에 관한 연구)

  • Seok jeong-Won;Choi Jong-Koen
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.5
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    • pp.175-181
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    • 2005
  • Ingots of rutile single crystals were grown by the skull melting method, and their characteristics were compared in terms of melt-dwelling time for each melt. The method is based on direct inductive heating of an electrically conducted melt by an alternating RF field, and the heating is performed by absorption of RF energy. TiO2 is an insulator at room temperature but its electric conductivity increases elevated temperature. Therefore, titanium metal ring(outside diameter : 6cm, inside diameter : 4cm, thickness 0.2cm) was embedded into TiO2, powder (anatase phase, CERAC, 3N) for initial RF induction heating. Important factors of the skull melting method are electric resistivity of materials at their melting point, working frequency of RF generator and cold crucible size. In this study, electric resitivity of TiO2, (102\~101Ωm) at its melting point was estimated by compairing the electric resitivities of alumina and zirconia. Inner diameter and height of the cold crucible was 11 and 14cm, respectively, which were determined by considering of the Penetration depth (0.36\~1.13cm) and the frequency of RF generator.