• Particle and aerosol research
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• 제10권4호
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• pp.131-136
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• 2014

The importance of waste treatments is increasing because of the lack of resources and environmental problems resulted from economic growth policy. Especially, the pollutant dust which is one of the wastes should be treated considerately because it could cause secondary damages on the human health as well as environmental systems. Recently, massive amount of coal fly-ash is being produced in thermoelectric power plants. In this study, we compared two general methods used in estimating the amount of unburned carbon in fly-ashes to categorize the coal fly-ashes into several groups following their carbon contents. One is the "loss on ignition(KS L 5405) method" which estimates the change of mass after combustion, and it is generally used. Another one is measuring $CO_2$ gas content by burning solid carbon in the fly-ash, and it is called "$CO_2$ analysis method."

• Transactions of the Korean Society of Mechanical Engineers B
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• 제31권8호
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• pp.672-679
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• 2007

The combustion characteristics of a liquefied petroleum gas-di-methyl ether (LPG-DME) compression ignition engine was investigated under homogeneous charge and stratified charge conditions. LPG was used as the main fuel and injected into the combustion chamber directly. DME was used as an ignition promoter and injected into the intake port. Different LPG injection timings were tested to verify the combustion characteristics of the LPG-DME compression ignition engine. The combustion was divided into three region which are homogeneous charge, stratified charge, and diffusion flame region according to the injection timing of LPG. The hydrocarbon emission of stratified charge combustion was lower than that of homogeneous charge combustion. However, the carbon monoxide and nitrogen oxide emission of stratified charge combustion were slightly higher than those of the homogeneous charge region. The indicated mean effective pressure was reduced at stratified charge region, while it was almost same level as the homogeneous charge combustion region at diffusion combustion region. The start of combustion timing of the stratified charge combustion and diffusion combustion region were advanced compared to the homogeneous charge combustion. It attributed to the higher cetane number and mixture temperature distribution which locally stratified. However, the knock intensity was varied as the homogeneity of charge was increased.

• Fire Science and Engineering
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• 제14권2호
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• pp.7-13
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• 2000

We had investigated thermal stability, Ignition temperature and fire gas for polyurethane foams used for manikin, cushion and interior finishing material. Decomposition of polyurethane foams with temperature was investigated using a DSC and the weight loss with temperature increase using a TGA in order to find the thermal hazard of polyurethane foams, and the ignition temperature of polyurethane foams according to species. We studied constant temperature among ignition temperature measuring methods. In addition, noxious gases for polyurethane foams according to combustion condition were analyzed using gas analyzer and GASTEC. As results, initial decomposition temperature of polyurethane foam used for interior finishing material was lower than those for manikin and cushion, and exothermic energy was higher. Ignition temperature of polyurethane foam of interior finishing material was $420^{\circ}$. All of combustion forms at $427^{\circ}$ and under were smoldering combustion, and it was combustion at $500^{\circ}$. As furnace temperature was increased, concentration of noxious gases such as carbon oxide, carbon dioxide, and hydrogen cyanide was increased. And nitrogen oxide at combustion condition($500^{\circ}$) was over 10 ppm.

• Nuclear Engineering and Technology
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• 제43권4호
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• pp.391-398
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• 2011

The U metal chips generated in developing nuclear fuel and a gamma radioisotope shield have been stored under immersion of water in KAERI. When the water of the storing vessels vaporizes or drains due to unexpected leaking, the U metal chips are able to open to air. A new oxidation treatment process was raised for a long time safe storage with concepts of drying under vacuum, evaporating the containing water and organic material with elevating temperature, and oxidizing the uranium metal chips at an appropriate high temperature under conditions of controlling the feeding rate of oxygen gas. In order to optimize the oxidation process the uranium metal chips were completely dried at higher temperature than $300^{\circ}C$ and tested for oxidation at various temperatures, which are $300^{\circ}C$, $400^{\circ}C$, and $500^{\circ}C$. When the oxidation temperature was $400^{\circ}C$, the oxidized sample for 7 hours showed a temperature rise of $60^{\circ}C$ in the self-ignition test. But the oxidized sample for 14 hours revealed a slight temperature rise of $7^{\circ}C$ representing a stable behavior in the self-ignition test. When the temperature was $500^{\circ}C$, the shorter oxidation for 7 hours appeared to be enough because the self-ignition test represented no temperature rise. By using several chemical analyses such as carbon content determination, X-ray deflection (XRD), Infrared spectra (IR) and Thermal gravimetric analysis (TGA) on the oxidation treated samples, the results of self-ignition test of new oxidation treatment process for U metal chip were interpreted and supported.

• Journal of the Korean Society of Combustion
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• 제11권2호
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• pp.1-6
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• 2006

This report presents a study of the development of an advanced coal nozzle used in burners to reduce unburned carbon (UBC) in a tangential coal-fired boiler. To understand the mechanism of UBC reduction, experiments using conventional burners were carried out to evaluate the effects of air injection velocity, coal fineness and over fired air (OFA) on combustion efficiency. It was confirmed that ignition of pulverized coal particles close to the burner is helpful toward the complete burn of residual carbon in fly ash. These efforts indicated the additional results that UBC was strongly dependent on the primary air velocity and coal fineness; especially that UBC dramatically decreased when the weight fraction of pulverized coal under $75{\mu}m$ was over 85 %. New coal nozzles, modified from conventional nozzles, were prepared and tested to improve the combustion efficiency. Some of these nozzles offered relatively lower unburned carbon than those of conventional burners and are referred to as HPFS (High Performance Flame Stability) coal nozzles.

• Transactions of the Korean Society of Automotive Engineers
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• 제18권1호
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• pp.37-43
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• 2010

The purpose of this paper is to investigate the effect of air-fuel ratio on the combustion and emissions characteristics of spark ignition (SI) gasoline engine fueled with bio-ethanol. A 1.6L SI engine with 4 cylinders was tested on EC dynamometer. In addition, lambda sensor and lambda meter were connected with universal ECU to control the lambda value which is varied from 0.7 to 1.3. The engine performance and combustion characteristics of bio-ethanol fuel were compared to those obtained by pure gasoline. Furthermore, the exhaust emissions such as carbon monoxide (CO), unburned hydrocarbon (HC), oxides of nitrogen ($NO_X$) and carbon dioxide ($CO_2$) were measured by emission analyzers. The results showed that the brake torque and cylinder pressure of bio-ethanol fuel were slightly higher than those of gasoline fuel. Brake specific fuel consumption (BSFC) of bio-ethanol was increased while brake specific energy consumption (BSEC) was decreased. The exhaust emissions of bio-ethanol fuel were lower than those of gasoline fuel under overall experimental conditions. However, the specific emission characteristics of the engine with bio-ethanol fuel were influenced by air-fuel ratio.

• Journal of The Korean Society of Clinical Toxicology
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• 제19권2호
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• pp.127-132
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• 2021

Purpose: It is known that the most common cause of gas poisoning in Korea is suicide attempts by burning ignition coals. Ignition coals are made from waste wood, and studies have been reported that heavy metals are emitted when this coal is burned. However, there was no study on how much heavy metal poisoning occurs in the human body through this, so this study was planned to find out whether the concentration of heavy metals in the blood increased in patients exposed to ignition coal combustion. Methods: From April 2020 to April 2021, blood lead, mercury, and cadmium concentrations were investigated in carbon monoxide poisoning patients who visited one regional emergency medical center in Seoul, and their association with exposure time, source of poisoning, and rhabdomyolysis were investigated. Results: During the study period, a total of 136 carbon monoxide poisoning patients were tested for heavy metals, and 81 cases of poisoning by ignition coal were reported. When comparing poisoning caused by combustion of ignition coal and other substances, there was no difference in the concentrations of lead, mercury, and cadmium in the blood, and there was no difference in the number of patients above the reference range. However, the patients exposed to more than 5 hours of ignition coal gas exposure are more frequent than those in the group less than 5 hours in lead (51.4% vs. 23.9%, p=0.012). Conclusion: Compared to poisoning with other combustible substances, the blood concentration of lead, mercury, and cadmium does not increase further in patients with gas poisoning by ignition coal. However, prolonged exposure may result in elevated levels of lead.

• Environmental Engineering Research
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• 제22권3호
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• pp.294-301
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• 2017

This paper is based on experiments conducted on a stationary, four stroke, naturally aspirated air cooled, single cylinder compression ignition engine coupled with an electrical swinging field dynamometer. Instead of 100% diesel, 20% Jatropha oil methyl ester with 80% diesel blend was injected directly in engine beside 25% pre-mixed charge of diesel in mixing chamber and with 20% exhaust gas recirculation. The performance and emission characteristics are compared with conventional 100% diesel injection in main chamber. The blend with diesel premixed charge with and without exhaust gas recirculation yields in reduction of oxides of nitrogen and particulate matter. Adverse effects are reduction of brake thermal efficiency, increase of unburnt hydrocarbons (UBHC), carbon monoxide (CO) and specific energy consumption. UBHC and CO emissions are higher with Diesel Premixed Combustion Ignition (DPMCI) mode compared to compression ignition direct injection (CIDI) mode. Percentage increases in UBHC and CO emissions are 27% and 23.86%, respectively compared to CIDI mode. Oxides of nitrogen ($NO_x$) and soot emissions are lower and the percentage decrease with DPMCI mode are 32% and 33.73%, respectively compared to CIDI mode.

• Applied Chemistry for Engineering
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• 제4권4호
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• pp.709-714
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• 1993

The cetane number is a measure of ignition quality, specifically ignition delay, of diesel fuel. It is an engine measure of kinetic phenomena. The ignition quality such as kinetic behavior does correlate with the molecular structure, the carbon type structural composition. In fact, we use the group additivity rule to dissect the molecular structures and predict cetane number. In this study, the use of $^{13}C-Nuclear$ Magnetic Resonance spectroscopic measuring the molecular structure and group additivity rule at different diesel fuels, whose cetane numbers were determined on a number of standard cetane rating engines is proposed to predict cetane numbers that relate the carbon type structural composition. The effect of the molecular structures on the cetane numbers has been studied.

• Journal of Environmental Science International
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• 제13권7호
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• pp.619-626
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• 2004

We have studied the catalytic combustion of soot particulates over perovskite-type oxides prepared by malic acid method, The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions such as temperature and $O_2$ concentration were investigated. The partial substitution of alkali metals into A site in the $LaMnO_3$ catalyst, enhanced the catalytic activity in the combustion of carbon particulate and the activity was shown in the order: Cs > K > Na. For the $La_{1-x}Cs_{x}MnO_{3}$ catalysts, the catalytic activity showed the maximum value with x=0.3 but no more increase on the catalytic activity was shown with x > 0.3. For the $La_{0.8}Cs_{0.2}MnO_{3}$ catalyst, the substitution of Fe or Ni increased the ignition temperature. The ignition temperature decreased with an increase of $O_2$ concentration, however, no more increase in the catalytic activity was shown with $O_2$ concentration > 0.2. The introduction of NO into reactants showed no effect on the catalytic activity.