• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.441-446
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• 2011

본 연구에서는 건축물에 화재가 발생 시, 건축용 외장재로부터 발생하는 연소가스의 독성을 분석함으로써 소방관을 비롯한 건물 재실자들에게 미치는 영향에 대해서 고찰하였다. 실험 방법은 건물의 외장재로 많이 사용되는 일반스티로폼, 강화스티로폼, 우레탄폼 그리고 유리섬유 재질의 외장재를 대상으로 NES 713 방법을 이용하였다. 실험 결과를 살펴보면, 대부분의 시료들로부터 CO, $CO_2$, HCHO, $CH_2CHCN$, $NO_x$ 등이 검출되었으며, 우레판폼의 경우, 다른 시료들과 달리 HCl과 HCN이 추가적으로 검출되었다. 하지만 대부분의 시료들로부터 검출된 독성가스들은 치사농도에는 훨씬 못미치는 것으로 나타났으며, 독성지수 값들을 살펴보면, 일반스티로폼<강화스티로폼<유리섬유<우레판폼의 순으로 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4111-4116
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• 2013

The progressive die producing continuously while transferring in order a multiple process is processing law that it is efficient and quality is excellent. In this study the position of precision secured that it occurred when be welded exhaust efficiency of gas boiler combustion exhaust pipe and the exhaust pipe which is cause of incomplete combustion for the purpose of productivity increase. it add burring to a product form and progressive die make die don't disassemble and it be able to exchange burring punch the position of precision and productivity by progressive die is able to improve.

• Fire Science and Engineering
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• v.30 no.6
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• pp.57-63
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• 2016

In this study, the toxicity of combustion products of wood-based materials (MDF, OSB) were analyzed using experimental animal techniques. The average deed stopping time of MDF was shorter than that of OSB. This means that the toxicity of the combustion products of MDF is higher than that of OSB. To analyze the cause of the result quantitatively, Fourier transform infrared spectroscopy (FT-IR) of the gas phase materials was performed. Qualitative analysis result, CO and $CO_2$ were detected. Quantitative analysis results, the gas generation rate was higher in OSB than in MDF. Blood analysis of mice revealed, COHb to be higher in OSB than MDF. A correlation between the gas generation rate and COHb was found. Currently, the toxicity of the combustion products of the materials is being examined using the toxicity index, such as Fractional Effective Dose (FED). The FED is based on the gas emissions. The average deed stopping time decreased with increasing toxicity of exposed material. On the other hand, the result of this study showed that, the CO emissions of OBS were 186.5% that of MDF. The COHb of OSB was > 129.6% that of MDF. Nevertheless, the average deed stopping time of the OSB is 51 seconds longer than that of MDF. Therefore, more toxicity studies on factors other than the gas phase materials in the combustion products will be needed.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.27-36
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• 2013

Linear stability analysis for combustion instability within a cylindrical port of solid rocket motor has been conducted. The analysis of acoustic energy has been performed by a commercial COMSOL code to obtain the mode function associated to each acoustic mode prior to the calculation of stability alpha. An instability diagnosis based on the linear stability analysis of Culick is performed where special interests have been focused on 5 stability factors(alpha) such as pressure coupling, nozzle damping, particle damping and additionally, flow turning effect and viscous damping to take into account the flow and viscosity effect near the fuel surface. The instability decay characteristics depending on the particle size is also analyzed.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.100-107
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• 2016

In this study confirmed the reduction effect of pollutant by applying Fi-EGR and FPI-EGR to hybrid combustion system realizing premixed flame and non-premxied flame at once. The results showed that NOx emission index decreased significantly in case of adopting EGR. Additionally, the hybrid combustion system with EGR resulted in a better performance compared to usual non-premixed combustion system such that it can reduce $NO_x$ emission at equivalent EGR ratios. Especially, in the case of 25% of FI-EGR ratio at hybrid combustion system that the ratio of non-premixed and premixed is 50 : 50, NOx emission index reduction rate was about 59% compared to $NO_x$ emission of non-premixed combustion system without EGR and in the case of 15% of FPI-EGR ratio at hybrid combustion system that the ratio of non-premixed and premixed is 70 : 30, $NO_x$ emission index reduction rate was about 48% compared to $NO_x$ emission of hybrid combustion system without EGR.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.21-25
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• 2010

Burnup of spent fuel should be determined accurately for the safety control of spent fuel. Especially, it is necessary to measure the burnup profile along the nuclear fuel axis. In the present work, an ionization chamber was designed and fabricated to measure the gamma ray profile inside the guide tube of spent fuel. The ionization chamber was composed of three parts; induction part, gas-inlet part, and sensor part. The sensor part had two electrodes; cathode and anode. A guide electrode was considered in the ionization chamber design to make the ionization chamber to be inserted easily into the guide tube. Pure gas (argon and xenon) was inserted into the ionization chamber, and the leakage current and saturation curve were measured to determine the operation characteristics of the ionization chamber. The gamma ray radiation was also measured in relatively high dose environment. The gamma ray profile of the spent fuel will be measured with the ionization chamber.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.335-342
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• 2012

Nowadays, automobile manufacturers are focusing on the reduction of exhaust-gas emissions because of the harmful effects on humans and the environment, such as global warming by greenhouse gases. Gasoline direct injection (GDI) combustion is a promising technology that can improve fuel economy significantly compared to conventional port fuel injection (PFI) gasoline engines. In the present study, ultra-lean combustion with an excess air ratio of over 2.0 is realized with a spray-guided-type GDI combustion system, so that the fuel consumption is improved by about 13%. The level of exhaust-gas emissions and the operation performance with the multiple injection strategy and exhaust-gas recirculation (EGR) are examined in comparison with the emission regulations and from the point of view of commercialization.

• Fire Science and Engineering
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• v.33 no.2
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• pp.47-55
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• 2019

The prediction performance of design fire curves was evaluated using a Fire dynamics simulator (FDS) for a solid fuel fire in a building space by comparing the results with experimental data. EDC 2-step mixing controlled combustion model was used in the FDS simulations and the previously suggested 2-stage design fire (TDF), Quadratic and Exponential design fire curves were used as the FDS inputs. The simulation results showed that smoke propagation in the building space was significantly affected by the design fire curves. The predictions of simulations using design fire curves for the experimental temperatures in the building space were reasonable, but the TDF was found to be the most acceptable for predicting temperature. The predictions with each design fire curve of species concentrations showed insufficient agreement with the experiments. This suggests that the combustion model used in this study was not optimized for the simulation of a solid fuel fire, and additional studies will be needed to examine the combustion model on the FDS prediction of solid fires.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.42-48
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• 2014

Soot and tar which were derived from combustion or pyrolysis processes in Puverized Coal(PC) furnace or boiler have been significantly dealing in a radiative heat transfer and an additional source of NOx. Furthermore, the increasing for the use of a coal with low caloric value gives rise to a lot of tar-soot yield and LOI in a recycled ash for using cement materials. So, the ash with higher tar-soot yield and LOI can not recycle due to decreased strength of concrete. In this study, tar-soot yields and flame structures were investigated using the LFR for a blending combustion with bituminous coal and sub-bituminous coal. Also, The investigation were conducted as each single coals and blending ratio. The coals are used in a doestic power plant. In the experimental results, sub-bituminous coal with high volatile contents shows longer soot cloud length than bituminous coal, but overall flame length was shorter than bituminous coal. Tar-soot yields of sub-bituminous coal is lower than those of bituminous coal. Combustion characteristics are different between single coal and blended coal. Therefore, finding an optimal coal blending ratio according to coal rank effects on tar-soot yields.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.315-324
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• 2012

This paper presents a numerical investigation of the deflagration-to-detonation transition (DDT) of flame acceleration by a shock wave filled with an ethylene/air mixture as the combustible gas, considering geometrical changes by using obstacles and bent tubes. The model used consists of the reactive compressible Navier-Stokes equations and the ghost fluid method (GFM) for complex boundary treatment. Simulations with a variety of bent tubes with obstacles show the generation of hot spots through flame and strong shock-wave interactions, and restrained or accelerated flame propagation due to geometrical effects. In addition, the simulation results show that the DDT occurs with a nearly constant chemical heat-release rate of 20 MJ/($g{\bullet}s$) in our numerical setup. Furthermore, the DDT triggering time can be delayed by the absence of unreacted material together with insufficient pressures and temperatures induced by different flame shapes, although hot spots are formed in the same positions.