• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.129-139
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• 2002

From the view of the environmental protection against the use of fossil fuels, a great of efforts have been exerted to find an alternative energy source. Hydrogen may become an alternative. However the product species of the hydrogen flame is only $H_2O$, which emits only non-luminous radiation so the radiation from it is much smaller than that for a hydrocarbon flame. In this study, the authors designed and fabricated a laboratory scale test furnace to study thermal characteristics of hydrogen-air diffusion flame. In addition, the effects of addition of reacting as well as non-reacting solid particles were experimentally investigated. Among the total heat flux to the wall, about 75% was occupied by radiation while 25 % by convection. When the aluminum oxide ($Al_2O_3$) particles were added, the radiative heat flux was reduced due to heat blockage effects. On the other hand, the total as well as the radiative heat flux was increased when the carbon particles were seeded, since the overall temperature increased. The effects of swirl and excess air ratio were also examined.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.131-134
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• 2015

국내 천연가스 열량제도를 현행 표준 열량제 $10,400kcal/Nm^3(43.54MJ/Nm^3)$에서 중간 조정기간을 두고 2012.07.01부터는 최저 $10,100kcal/Nm^3(42.28MJ/Nm^3)$을 유지하고 2015년 이후 $9,800(41.1MJ/Nm^3){\sim}10,600kcal/Nm^3(44.4MJ/Nm^3)$ 열량범위제도로 변경 추진되고 있다. 산업현장에서 열량변동을 측정하여 공연비 제어기술을 개발하고자 60ton Al 용해로에 열량대응기술 개발을 위한 내용으로 열량측정시스템설치 및 열량 값과 연계하여 공연비 제어기술개발연구 내용으로 결과는 다음과 같다. 단순히 표준열량으로 에 맞춰 프로그램된 제어로직에 열량변동에서 검출된 신호를 이용하여 연료보정 값을 추가한 로직을 재구성할 필요가 있다. 이 혀장의 경우는 용탕의 온도가 목표온도 근처까지 올리기가 어려워진 상황으로 주로 공급열량 저열량화에 따른 과잉공기영향으로 온도상승이 어려워 보이며 적절한 공연비로 최적화 되면 이러한 문제가 개선되리라 생각된다.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.391-397
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• 2014

Acid mine drainage occurrence is a serious environmental problem by mining industry; it usually contain high levels of metal ions, such as iron, copper, zinc, aluminum, and manganese, as well as metalloids of which arsenic is generally of greatest concern. It causes mine impacted soil pollution with mining and smelting activities, fossil fuel combustion, and waste disposal. In the present study, three bacterial strains capable of producing urease were isolated by selective enrichment of heavy metal contaminated soils from a minei-mpacted area. All isolated bacterial strains were identified Sporosarcina pasteurii with more than 98% of similarity, therefore they were named Sporosarcina sp. KM-01, KM-07, and KM-12. The heavy metals detected from the collected mine soils containing bacterial isolates as Mn ($170.50mg\;kg^{-1}$), As ($114.05mg\;kg^{-1}$), Zn ($92.07mg\;kg^{-1}$), Cu ($62.44mg\;kg^{-1}$), and Pb ($40.29mg\;kg^{-1}$). The KM-01, KM-07, and KM-12 strains were shown to be able to precipitate calcium carbonate using urea as a energy source that was amended with calcium chloride. SEM-EDS analyses showed that calcium carbonate was successfully produced and increased with time. To confirm the calcium carbonate precipitation ability, urease activity and precipitate weight were also measured and compared. These results demonstrate that all isolated bacterial strains could potentially be used in the bioremediation of acidic soil contaminated by heavy metals by mining activity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.32-37
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• 2003

The trend of miniaturization has been applied to the research on micro rockets resulting in prototype rockets fabricated by MEMS processes. In this paper, the development of three-dimensional micro rockets using micro milling as well as the results of combustion and flight tests are discussed. The body of rocket was made of 6061 aluminum cylinder. The three-dimensional micro nozzles were fabricated on brass by micro endmill with 127${\mu}m$ diameter. Two different micro nozzles were fabricated, one with 1.0mm of throat diameter and the other with 0.5mm. The total mass of rocket was 7.32g and that of propellant was 0.65g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle form the ground resulted in 46m-53m of horizontal flight distance

• Tribology and Lubricants
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• v.25 no.6
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• pp.387-398
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• 2009

The operation condition of recently designed pistons for high power and high speed diesel engine become more severe due to the increment of combustion pressure and temperature. So, in order to overcome high temperature, the application of the mono-metal cast aluminum alloy piston featuring an enclosed cast-in open cooling gallery has increased. In this research, it is developed a PCJ (piston cooling jet) rig tester, described the test procedure and validated the performance of sample piston cooling gallery design. Then the test rig will be used for developing the design technology of piston cooling gallery. The test rig is composed with oil reservoir and pumping system, oil jet system, piston fixing and moving system, collecting oil measuring system, and data measuring and recording system. It will be measured collecting efficiencies under conditions of a few piston positions, oil jet pressures and oil viscosities for a piston cooling gallery. Furthermore, the PCJ rig tester will be used for the optimum design of the oil cooling gallery which being applied to increase the cooling efficiency of pistons in diesel engines satisfying the EURO V emission regulation and the more.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.10-18
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• 2017

The problem of non-ideal detonation propagation velocities in heterogeneous hybrid mixtures is studied in the case of a high explosive with suspended fine aluminum (Al) particles. Since there exist difference in the time scales of the characteristic induction and combustion of High Explosives and solid particles, the process of energy release behind the leading shock front occurs over an extended period of time. The problem is analyzed by the theory of the mechanics of multiphase media with mass, momentum and heat exchanges between particles and gases. The numerical results match the available experimental results of heavily aluminized (5~25% Al weight) HMX explosive obtained previously.

• Fire Science and Engineering
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• v.29 no.6
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• pp.76-83
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• 2015

EPS sandwich panel contains flame retardants that slow down ignition during fires,reduce the amount of heat generated, and block the spread of combustion. However, if a sandwich panel does not satisfy standards for fire-retardant performance, it may increase damage to property and human life. It is difficult to test the fire-retardant performance of a finishing material with the naked eye, so it is necessary to develop convenient and fast evaluation methods that are convenient and fast. In this study, a fire safety evaluation method for EPS sandwich panel was analyzed using X-ray to detect specific components related to the fire-retardant performance X-ray fluorescence analysis (XRF) indicated that suitable panel products contained more aluminum in comparison to unsuitable products. Gibbsite was identified as the main crystalline material of flame retardant EPS through X-ray diffraction analysis (XRD) and was included in both suitable products and unsuitable products, but there was a difference in crystalline structure. This study was verifies the possibility of evaluating fire-retardant performance using ultimate analysis and crystal analysis through these X-ray methods.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.545-550
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• 2012

High Energy density metal powder has high melting point of oxide film. By this, the ignition source that can make a thermal effect of high-temperature during short time is needed to overcome ignition disturbance mechanism by oxide film. So effective ignition does not occurred with hydrocarbon ignitor, $H_2-O_2$ ignitor, high power laser. But steam plasma can be generate about 5000 K temperature field in short order. Because a steam plasma uses steam as the working gas, it is environmental-friendly and economical. Therefore in this study, we analyze steam plasma temperature field and radical species with optical emission spectroscopy method in order to apply steam plasma ignitor to metal combustion system and cloud particle ignition was identified in visual.

• Clean Technology
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• v.26 no.3
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• pp.221-227
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• 2020

When the waste solid fuel (SRF, Bio-SRF) is burnt in a boiler, a problem occurs in the combustion process involving the alkali components (Na, K) contained in large amounts in the fuel. The alkaline component has a low melting point, which usually forms low melting point salt in the temperature of the furnace, with the resulting low melting point salts attaching to the heat pipe to form a clinker. Various additives are used to suppress clinker generation, and the additive based on the kaolinite has alkali-aluminum-silica to inhibit the clinker. In this study, the reactivity of the additives based on the kaolinite was compared. The additives utilized were R-kaolinite, B-kaolinite, and A-kaolinite. Also silica and MgO were sourced as the comparison group. The experimental group was employed as a laboratory-scale batch horizontal reactor. The additive and alkaline salts were reacted at a weight ratio of 1 : 1, and the reaction temperature was performed at 900 ℃ for 10 hours. The first measurement of HCl occurring during the experiment was performed 30 minutes after the detection tube was used, and the process was repeated every hour after the experiment. After the reaction, solid residues were photographed for characterization analysis by means of an optical microscope. The reaction characteristics of the kaolinite were confirmed based on the analysis results.

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.84-91
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• 2017

Recent years have witnessed the increased usage of flammable metals, such as aluminum or magnesium, in wide range of high-tech industries. These metals are indispensable for the improvement of physical properties of materials as well as the design capability of the final product. During the process, unwanted metal dusts could be released to the environment. This can lead to an occupational health and safety issues. Due to their flammable nature, more serious problem of an explosion can happen in extreme cases. The explosion is the combustion of tiny solid particles and vapor mixture, caused by pyrolysis. This complex composition makes engineering analysis more difficult, compared to simple gas explosions or vapor cloud combustions. The study was conducted to assess this light metal dust explosion in an effort to provide the bases for a risk assessment. Dust explosion characteristics of each material was carefully evaluated and an appropriate analysis tool was developed. A comprehensive database was also constructed and utilized for the calibration of the developed response model and the verification for its accuracy. Subsequently, guidelines were provided to prevent dust explosions that could occur in top-notch industrial processes.