• Title, Summary, Keyword: Exothermic Reaction

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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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Thermal Analysis of Poly(Sodium 4-Styrenesulfonate) Intercalated Graphite Oxide Composites

  • Jeong, Hye-Gyeong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.555-555
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    • 2012
  • The thermal stability of poly(sodium 4-styrenesulfonate) intercalated graphite oxide has been investigated using a differential scanning calorimeter. The poly(sodium 4-styrenesulfonate) intercalated graphite oxide composite shows a prominent exothermic reaction near $207^{\circ}C$ and an endothermic reaction near $453^{\circ}C$. Graphite oxide is responsible for the exothermic reaction while the endothermic reaction is caused by the poly(sodium 4-styrenesulfonate) used in the synthesis of poly(sodium 4-styrenesulfonate) intercalated graphite oxide. The onset temperature of the exothermic reaction of poly(sodium 4-styrenesulfonate) intercalated graphite oxide decreased by $92^{\circ}C$ in comparison with that of graphite oxide, indicating the addition of poly(sodium 4-styrenesulfonate) in the composite has diminished the thermal stability of graphite oxide.

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Evaluation System of the Thermal Properties of the Exothermic & Insulating Materials (발열 보온재의 특성평가 시스템 구축)

  • Shin, D.Y.;Kim, D.J.;Jun, B.H.;You, B.D.;Kim, N.S.;Oh, S.H.
    • Transactions of Materials Processing
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    • v.17 no.5
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    • pp.356-363
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    • 2008
  • An evaluation system of the thermal properties of exothermic & insulating materials was developed. By measuring the power supply of the induction furnace, the thermal property of exothermic & insulating materials could be evaluated with high reproducibility at elevated temperature of molten steel. The thermal properties of exothermic & insulating materials were affected by mixing condition of raw materials. The effect of main components of exothermic & insulating materials such as metallic aluminum and $Fe_2O_3$ powder on the exothermic and insulating properties was examined. It could be expected to design and develop various exothermic & insulating materials by means of the evaluation system of the thermal properties.

A Study on Dielectric Properties of $TiO_2$-Based Ceramics ($TiO_2$계 세라믹스의 유전특성에 대한 연구)

  • You, Do-Hyun
    • Proceedings of the KIEE Conference
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    • pp.167-170
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    • 2006
  • $TiO_{2}-Nb_{2}O_{5}$ sol was prepared using sol-gel method. DTA properties of gel powder had endothermic reaction due to evaporation of propanol and water about $78^{\circ}C$, had exothermic reaction due to propanol combustion about $290^{\circ}C$ and had exothermic reaction due to changing of $TiO_2$ phase about $640^{\circ}C$. Capacitance of thin films increased according to increasing relative humidity, whereas it decreased according to increasing measured frequency.

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THERMAL IGNITION OF A REACTION DIFFUSION SYSTEMS IN SOME CLASS A GEOMETRIES WITH DIFFERENT THERMAL BOUNDARY CONDITIONS

  • Ajadi, S.O.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.11 no.3
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    • pp.7-20
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    • 2007
  • We examined the steady state solution for a strongly exothermic mixtures in some class A geometries subjected to different boundary conditions under Arrhenius, Bimolecular and Sensitised reactions. The solution of the governing nonlinear reaction diffusion equation was obtained using the variational method formulation executed in Mathematica package. The paper elucidates the influence of geometry, boundary conditions and types of reaction on the thermal ignition of the reactive mixture. Apart from validating known results in literature, the solution gave further insight into the influence of material properties and conditions on the occurrence of thermal ignition.

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A Study on the Thermal Decomposition Characteristics of Nitrophenylhydrazine (니트로페닐하이드라진의 열분해 특성에 관한 연구)

  • 김관응;이근원
    • Journal of the Korean Society of Safety
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    • v.16 no.2
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    • pp.75-79
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    • 2001
  • For handling and storage of reactive chemicals, the hazard evaluations have been extremely important. In the chemical industry, the most concerns are focused on the thermal harzards such as runaway reactions and thermal decompositions, which are mostly governed by thermodynamics and reaction kinetics or these reactive chemical in the system. This study no investigated the thermal decomposition characteristics of nitrophenylhydrazine isomers by using differential scanning calorimeter(DSC) and accelerating rate calorimeter(ARC). Experimental results showed that exothermic onset-temperatures in nitrophenylhydrazine(NPH) isomers were about 160-$210^{\circ}C$ by DSC and 100-$150^{\circ}C$ by ARC. The decomposition temperature acquired by ARC was about 50-$60^{\circ}C$ lower than that by DSC. Reaction heats were about 40-100cal/g by DSC and 330-750ca1/g by ARC. While ortho isomer of NPH show two distinct exothermic peaks, para isomer shows a single peak in DSC curves. The first exothermic peak for 2-NPH is mainly due to intramolecular dehydration forming 1-hydroxybenzotriazole(HOBT) and the second exothermic peak is mainly due to the decomposition of HOBT formed in the first step of decomposition. The exothermin peak in the DSC curve for 4-NPH is mainly due to dissociation of hydrazino and nitro groups.

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Thermite Reaction Between CuO Nanowires and Al for the Crystallization of a-Si

  • Kim, Do-Kyung;Bae, Jung-Hyeon;Kim, Hyun-Jae;Kang, Myung-Koo
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.5
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    • pp.234-237
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    • 2010
  • Nanoenergetic materials were synthesized and the thermite reaction between the CuO nanowires and the deposited nano-Al by Joule heating was studied. CuO nanowires were grown by thermal annealing on a glass substrate. To produce nanoenergetic materials, nano-Al was deposited on the top surface of CuO nanowires. The temperature of the first exothermic reaction peak occurred at approximately $600^{\circ}C$. The released heat energy calculated from the first exothermic reaction peak in differential scanning calorimetry, was approximately 1,178 J/g. The combustion of the nanoenergetic materials resulted in a bright flash of light with an adiabatic frame temperature potentially greater than $2,000^{\circ}C$. This thermite reaction might be utilized to achieve a highly reliable selective area crystallization of amorphous silicon films.

A Study on the Spontaneous Ignition Probability of caused the Quicklime (생석회의 자연발화 가능성에 관한 실험적 연구)

  • Choi, I.H.;Park, S.B.;Lee, I.J.;Ha, J.H.;Lee, W.B.;Choi, D.M.
    • Journal of Korean Institute of Fire Investigation
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    • v.11 no.1
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    • pp.139-144
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    • 2007
  • The fires were occasionally occurred by the quicklime, used in soil conditioners and stall disinfectant, in the stables and shed especially during the rainy season. Accordingly, we observed that spontaneous ignition by the exothermic reaction was happened through the revival experiments. As a results of revival experiments, we confirmed that fire had been occurred by exothermic energies in the case of heat accumulation.

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Numerical Analysis of Steam-methane Reforming Reaction for Hydrogen Generation using Catalytic Combustion (촉매 연소를 열원으로 한 수증기-메탄개질반응 전산유체해석)

  • Lee, Jeongseop;Lee, Kanghoon;Yu, Sangseok;Ahn, Kookyoung;Kang, Sanggyu
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.2
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    • pp.113-120
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    • 2013
  • A steam reformer is a chemical reactor to produce high purity hydrogen from fossil fuel. In the steam reformer, since endothermic steam reforming is heated by exothermic combustion of fossil fuel, the heat transfer between two reaction zones dominates conversion of fossil fuel to hydrogen. Steam Reforming is complex chemical reaction, mass and heat transfer due to the exothermic methane/air combustion reaction and the endothermic steam reforming reaction. Typically, a steam reformer employs burner to supply appropriate heat for endothermic steam reforming reaction which reduces system efficiency. In this study, the heat of steam reforming reaction is provided by anode-off gas combustion of stationary fuel cell. This paper presents a optimization of heat transfer effect and average temperature of cross-section using two-dimensional models of a coaxial cylindrical reactor, and analysis three-dimensional models of a coaxial cylindrical steam reformer with chemical reaction. Numerical analysis needs to dominant chemical reaction that are assumed as a Steam Reforming (SR) reaction, a Water-Gas Shift (WGS) reaction, and a Direct Steam Reforming(DSR) reaction. The major parameters of analysis are temperature, fuel conversion and heat flux in the coaxial reactor.

Thermal Behavior of Dickite (딕카이트의 열적 특성 연구)

  • 조현구
    • Journal of the Mineralogical Society of Korea
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    • v.12 no.1
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    • pp.11-22
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    • 1999
  • Thermal behavior of dickite was studied by thermal analysis, X-ray diffraction analysis, electron microprobe analysis, and scanning electron microscopy, Dickite has an endothermic peak at about$ 650^{\circ}C$ and an exothermic one at $960^{\circ}C$ in the differential thermal analysis. The endothermic reaction is assigned to the decomposition of dickite to meta-dickite. Hydroxyl radicals are removed from dickite structure by the reaction, resulting in the weight loss about 10.5~14.5% and appearance of a 14$\AA$ phase different from other kaolin minerals. The reaction slowly proceed in the range of $200^{\circ}C$. As the completion of decomposition, aciclular mullite forms at the expense of meta-dickite plates with random crystallographic relationship. Mullites have diverse silica versus alumina ratio. The exothermic reaction without weight loss seems to be due to the formation of spinel and amorphous silica. The spinel phase shows cryptocrystalline globular morphology accompanying a little amount of silica. From spinel phase shows cryptocrystalling globular morphology accompanying a little amount of silica. From this work, it is suggested that mullite is formed from meta-dickite much lower temperature than the reported one in the previous works.

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