• Title/Summary/Keyword: Thermal properties

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A Study on Electrical and Thermal Properties of Polyimide/MWNT Nanocomposites

  • Park, Soo-Jin;Chae, Sung-Won;Rhee, John-Moon;Kang, Shin-Jae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.8
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    • pp.2279-2282
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    • 2010
  • In this work, the electrical and thermal properties of polyimide/multi-walled carbon nanotube (MWNT) nanocomposites were investigated. The polyimide/MWNT nanocomposites contained from 0 to 2.0 wt % of MWNT. The electrical properties of the polyimide films were characterized by a specific resistance measurement. The thermal properties were evaluated using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). It was found that the thermal properties of the polyimide nanocomposites increased with increasing MWNT content and specific resistance as well. This result indicated that the crosslinking of polyimide/MWNT nanocomposites was enhanced by good distribution of the MWNT in the polyimide resins, resulting in the increase of the electrical and thermal properties of the nanocomposites.

Evaluation System of the Thermal Properties of the Exothermic Agents (발열 보온재의 특성평가 시스템 구축)

  • Shin, D.Y.;Kim, D.J.;You, B.D.;Kim, N.S.;Oh, S.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.46-51
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    • 2008
  • In this study, evaluation system of the thermal properties of the exothermic agents was investigated. Exothermic agents property evaluation system was developed by metering variation of power supply. Thermal properties of exothermic agents was affected by material mixture condition of exothermic agents, however, it was not affected by temperature. It is possible to make various exothermic agents by means of regulating thermal properties which is based on property evaluation system of exothermic agents.

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Effect of Mixing condition of raw materials on the Thermal Properties of the Exothermic & Insulating Materials (원료 배합조건에 따른 발열보온재의 열적 특성)

  • Kim, D.J.;Shin, D.Y.;Byun, S.Y.;Wi, C.H.;You, B.D.;Oh, S.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.118-126
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    • 2009
  • The change of the thermal properties of exothermic & insulating materials with mixing condition of raw materials which is the most important factor for exothermic & insulating materials was investigated by using the evaluation system of the thermal properties of exothermic & insulating materials. In this study, the effect of the thermal properties of the exothermic & insulating materials such as exothermic properties, endothermic properties, insulating properties, maximum temperature of molten metal, ignition time of exothermic & insulating materials and temperature recovery time on the mixing ratio of reductant and oxidant, types of reductant, and particle sizes of reductants was examined. It could be expected to design the mixing condition of raw materials for various exothermic & insulating materials.

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Effect of Mixing Condition of Raw Materials on the Thermal Properties of the Exothermic & Insulating (원료 배합조건에 따른 발열보온재의 열적 특성)

  • Kim, D.J.;Shin, D.Y.;Byun, S.Y.;Wi, C.H.;Hong, S.H.;You, B.D.;Oh, S.H.
    • Transactions of Materials Processing
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    • v.18 no.5
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    • pp.401-409
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    • 2009
  • The change of the thermal properties of exothermic and insulating materials with the mixing condition of raw materials which is the most important factor for exothermic & insulating materials was investigated by using the evaluation system of the thermal properties of exothermic and insulating materials. In this study, the effect of the thermal properties of the exothermic & insulating materials such as exothermic properties, endothermic properties, insulating properties, maximum temperature of molten metal, ignition time of exothermic & insulating materials and temperature recovery time on the mixing ratio of reductant and oxidant, types of reductant, and particle sizes of reductants was examined. It could be expected to design the mixing condition of raw materials for various exothermic and insulating materials.

A study on electrical and thermal properties of conductive concrete

  • Wu, Tehsien;Huang, Ran;Chi, Maochieh;Weng, Tsailung
    • Computers and Concrete
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    • v.12 no.3
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    • pp.337-349
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    • 2013
  • Traditional concrete is effectively an insulator in the dry state. However, conductive concrete can attain relatively high conductivity by adding a certain amount of electronically conductive components in the regular concrete matrix. The main purpose of this study is to investigate the electrical and thermal properties of conductive concrete with various graphite contents, specimen dimensions and applied voltages. For this purpose, six different mixtures (the control mixtures and five conductive mixtures with steel fibers of 2% by weight of coarse aggregate and graphite as fine aggregate replacement at the levels of 0%, 5%, 10%, 15% and 20% by weight) were prepared and concrete blocks with two types of dimensions were fabricated. Four test voltage levels, 48 V, 60 V, 110 V, and 220 V, were applied for the electrical and thermal tests. Test results show that the compressive strength of specimens decreases as the amount of graphite increases in concrete. The rising applied voltage decreases electrical resistivity and increases heat of concrete. Meanwhile, higher electrical current and temperature have been obtained in small size specimens than the comparable large size specimens. From the results, it can be concluded that the graphite contents, applied voltage levels, and the specimen dimensions play important roles in electrical and thermal properties of concrete. In addition, the superior electrical and thermal properties have been obtained in the mixture adding 2% steel fibers and 10% graphite.

Mechanical and Thermal Properties of Environmentally Benign Silicone Foam Filled with Wollastonite

  • Kim, Yongha;Joeng, Hyeonwoo;Lee, Kyoung Won;Hwang, Sosan;Shim, Sang Eun
    • Elastomers and Composites
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    • v.55 no.4
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    • pp.300-305
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    • 2020
  • In recent times, polymeric foams have been popularly used in various applications. To meet the demand for these applications, polymer foams with excellent mechanical and thermal properties are required. In particular, silicone foam has gained significant attention owing to its superior thermal properties and low density. In this study, the mechanical and thermal properties of silicone foams filled with wollastonite were investigated. A maximum tensile strength of 98.3 kPa was obtained by adding 15 phr of wollastonite. The specific gravity did not exhibit a marked difference up to 10 phr, but it increased substantially above 15 phr wollastonite. Thermogravimetric analysis indicated that adding wollastonite to the silicone foam increased both the amount of residue and the thermal decomposition temperature. The morphologies of the silicone foams filled with wollastonite were observed by scanning electron microscopy.

Comparison of Hand and Thermal Properties of Woven Fabrics Made from hollow and Regular Fibers (중공사와 원형사로 제직된 직물의 태와 열적 성질의 비교)

  • 심현주;홍경아;김형섭이경우
    • Textile Science and Engineering
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    • v.37 no.5
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    • pp.280-285
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    • 2000
  • This study shows the enhancement of thermal properties and the change of hand values due to the hollowness by comparing properties of fabrics made form hollow fibers are better compared with fabrics made from regular fibers, except for the frictional properties. the thermal properties measured by KES-F7(Thermo Labo II) system shows that the values of the initial maximum value($q_{max}$) and the thermal conductivity(λ) are higher in the fabricsmade from hollow fibers.

Preparation of PET Nanocomposites: Dispersion of Nanoparticles and Thermal Properties

  • Her, Ki-Young;Kim, Dae-Heum;Lim, Soon-Ho
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.4
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    • pp.71-73
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    • 2008
  • The development of polymer/inorganic nanocomposites has attracted a great deal of interest due to the improved hybrid properties derived from the two different components. Various nanoscale fillers have been used to enhance polymer mechanical and thermal properties, such as toughness, stiffness, and heat resistance. The effects of the filler on the final properties of the nanocomposites are highly dependent on the filler shape, particle size, aggregate size, surface characteristics, polymer/inorganic interactions, and degree of dispersion. In this paper, we describe the influence of different $CaCO_3$ dispersion methods on the thermal properties of polyethylene terephthalate (PET)/$CaCO_3$ composites: i.e., the adsorption of $CaCO_3$ on the modified PET surface, and the hydrophobic modification of the hydrophilic $CaCO_3$ surface. We prepared PET/$CaCO_3$ nanocomposites using a twin-screw extruder, and investigated their thermal properties and morphology.

The Study on the physical Properties of tencel fabrics (텐셀직물의 물리적 특성에 관한 연구)

  • Kwon, Oh Kyung;Kwon, HyunSun;Na, Young-Joo
    • Fashion & Textile Research Journal
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    • v.2 no.2
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    • pp.132-137
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    • 2000
  • This study was carried out to evaluate the distribution of mechanical and thermal properties of 14 sorts of tencel fabrics. Three kinds of cellulosic fabrics such as cotton 100%, cotton/tencel 50/50% and rayon 100% were used to compare with tencel fabrics. Furthermore, for the comparison of thermal properties, these fabrics were repeatedly washed 1, 3, 5, 10, 15 and 20 times respectively. The mechanical properties were measured by the KES-FB system and Thereto Labo II type was employed to measure the thermal properties of warmth retaining and contact warm/cool feeling($q_{max}$). The experimental results were analysed statistically to relate the mechanical and thermal properties. Tencel showed sufficient ability to recover from bending deformation and drapability comparing with other cellulosic fabrics and had a silhouette which goes along with the body.

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Thermal Properties and Spray Characteristics of Kerosene Fuel at High Temperature and Pressure (고온고압 환경에서 케로신 연료의 물성치변화 및 분무특성연구)

  • Byeon, Yong-Woo;Son, Min;Koo, Ja-Ye
    • Journal of ILASS-Korea
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    • v.15 no.2
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    • pp.94-99
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    • 2010
  • The object of this investigation is to study the thermal properties and spray characteristics of kerosene fuel in high temperature and pressure conditions. In order to investigate the thermal properties and spray characteristics, KIVA3 and SUPERTRAPP have been used at the same time. The thermal properties of kerosene has been calculated in high temperature and pressure condition using SUPERTRAPP. The study of spray characteristics has been conducted at both original properties of KIVA3 and calculated properties. The evaporation rate was increased in proportion to pressure when the calculated properties were used. However, the effect of pressure was not shown in the case of using original properties. So the calculated properties are more effective than original properties in high temperature and high pressure condition.