• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.1-5
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• 2019

In the field of combined cycle power generation, thermal barrier coating(TBC) protects the super-heat-resistant alloy, which forms the core component of the gas turbine, from high temperature exposure. As the turbine inlet temperature(TIT) increases, TBC is more important and durability performance is also important when considering maintenance cost and safety. Therefore, studies have been made on the fabrication method of TBC and super-heat-resistant alloy in order to improve the performance of the TBC. In recent years, due to excellent properties such as high temperature creep resistance and high temperature strength, turbine blade material have been replaced by a single crystal superalloy, however there is a lack of research on TBC applied to single crystal superalloy. In this study, to understand the isothermal degradation performance of the TBC applied to the single crystal superalloy, isothermal exposure test was conducted at various temperature to derive the delamination life. The growth curve of thermally grown oxide(TGO) layer was predicted to evaluate the isothermal degradation performance. Also, microstructural analysis was performed by scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS) to determine the effect of mixed oxide formation on the delamination life.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.360-366
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• 2018

In shipyards hull forming is performed by the line heating method using a gas torch and by cold treatment using a roll-press. However, this forming process has some issues, such as difficulties in controlling and accurately estimating the amount of the heat input, as well as a harsh working environment due to exposure to loud noises and air pollution. The induction heating method, which is introduced in this paper, exhibits good control and allows for the estimation of precise heat input. Also, workers can carry out the induction heating in a comfortable working environment. In this research, the induction heating simulation, which consists of electro-magnetic, heat transfer and thermal elasto-plastic analysis, was developed and modified through induction heating experiments. Finally, the effective heating coil was designed for the automatic hull forming system based on the results of induction heating simulation. For the purposes of a future study, if an algorithm to obtain optimal working conditions is developed, automatic systems for hull forming can then be constructed.

• Fire Science and Engineering
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• v.16 no.2
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• pp.75-80
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• 2002

In this paper, some experiments of a heat release rate and toxicity for underground utility 22.9kv cable in fire was conducted and analysed applying plume equation and smoke chamber test separately, A 22.9 ㎸ power cable is selected for testing heat release in ISO 9705 geometry and toxicity production is measured with NES 713 (British-Naval Engineering Standard)test. In test results, Cable heat release reached about 60 ㎾ above 1.2 m from heptane pan and CO generated lethal concentration under 30 min. exposure condition.

• Journal of Environmental Science International
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• v.10 no.1
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• pp.73-77
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• 2001

This study examined blends of styrene butadiene rubber(SBR) and chloroprene rubber(CR) prepared from an open 2-roll mill following the conventional polymer blend method for a wide range of the blend composition. Rubber vulcanizates were manufactured by hot press and then mechanical properties, heat and ozone resistance of the specimens were examined. Due to the post cure during the aging test, hardness of vulcanizates was increased. It was found that the undesirable characteristics of heat and ozone resistance of pure SBR was significantly improved through the blending of SBR with CR.

• Journal of the Korea Furniture Society
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• v.26 no.4
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• pp.467-473
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• 2015

Natural dyeing is considered to be an alternative to chemical staining in terms of harmful VOC-free and environmentally-friendly ingredient. This study was concerned with an evaluation of color performance of naturally dyed- and painted veneer for cylindrical laminated veneer lumber etc. according to the used condition in terms of existence of light and heat in drying. From the results, the color changes by the color of dyed veneer and the type of paint are likely to be affected by fading condition of light or heat. In the future, long-term outdoor exposure test needs to be additionally followed in order to evaluate durable usability of colored veneers.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.523-537
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• 2008

In Korea, the global warming leads to more frequent high temperature region. increasing the need for research into physical damage caused by high temperature. We therefore analyzed the differences of mortality, caused by extreme heat, among gender and age. We also examined the trend of mortality from high temperature-sensitive diseases. Women are more affected by exposure to high temperature than are men; People over 65 years old have higher mortality rate (1.5 times) than under 65. As for high temperature-related diseases, cerebrovascular disease was the number one cause of death, and chronic lower respiratory disease and cardiovascular disease followed.

• Journal of Life Science
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• v.14 no.1
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• pp.188-192
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• 2004

Toluene tolerance and therrnotolerance in Crampositive organic solvent resistant bacterium Micrococcus sp. BCNU 121 has been studied. Exposure to a sub- lethal temperature or a sub-lethal concentration of toluene conferred protection to subsequent challenges with a killing temperature or a lethal concentration of toluene, respectively. Pretreatment of Micrococcus sp. BCNU 121 with sub-lethal concentrations of toluene induced adaptative protection against heat shock. Moreover, temperature-adaptative cells also showed cross-resistance to lethal doses of toluene. These data suggested a cross-regulation between toluene tolerance and heat shock response.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.81-82
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• 2018

The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.

• Elastomers and Composites
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• v.53 no.3
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• pp.136-140
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• 2018

In this study, research was conducted into the manufacture of thermally expandable microspheres for automotive underbody coatings and applications in industry. In particular, the relationship between heat resistance and the ratio of crosslinking agents and initiators in the manufacture of the thermally expandable microspheres was investigated. We focused on the results with various cross-linking agents; our aim was to make the walls of the microspheres thicker to solve the problem of reductions in size caused by shrinkage when the microspheres are heated to $T_m$ ($T_{max}$). We observed the sectional thickness and surface of the samples with thicker walls. The thick thermally expandable microspheres showed reduced shrinkage and excellent stability in spite of prolonged exposure to heat.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.126-127
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• 2017

This study investigates the effect of improving the heat resistance performance when carbon fiber is mixed in the polyurea coating material. A tensile strength test method was carried out with the carbon fiber mixed polyurea specimens at an interval of 7, 14, and 21 days after heat treatment at 140±2℃. The test results showed that there was a significant decrease in the tensile strength performance. While the elongation and tensile performance decreased greatly, it was confirmed nevertheless the overall performance was maintained. This study proposes that mixing carbon fiber to the polyurea resin can effectively secure long-term heat resistance, thereby solving the problem of deterioration of physical properties caused by exposure to ultraviolet rays.