• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.675-681
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• 2012

The char oxidation characteristics of ashless coal with a relatively low ash content and high heating value were experimentally investigated at several temperatures (from $900^{\circ}C$ to $1300^{\circ}C$), in various oxygen concentrations (from 10% to 30%) under atmospheric pressure in a drop tube furnace. The char reaction rate was calculated from the exhaust gas concentrations (CO, $CO_2$) measured by FT-IR, and the particle temperature was measured by the two-color method. In addition, the activation energy and pre-exponential factor of ashless coal char were also calculated based on the Arrhenius equation. The results show that higher temperature and oxygen concentration result in a higher reaction rate of ashless coal, and the activation energy of ashless coal char is similar to that of bituminous coal.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.220-221
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• 2003

Equiatomic FePt and CoPt alloy thin films have received considerable attention as possible magnetic and magneto-optic recording because of their high magnetic anisotropy energy and high coercivity. The high coercivity in these thin films is due to the presence of finely dispersed ordered FePt phase mixed with disordered FePt phase. However, a high temperature treatment, either substrate heating during deposition or post annealing, is needed to obtain the ordered L1$\_$0/ phase with high value of magneto crystalline anisotropy. Recent microstructural studies on these films suggest that the average grain size ranges from 10-50 nm and the grains are magnetically coupled between each other. On the other hand, the ultrahigh-density magnetic recording media with low media noise imposes the need of a material, which consists of magnetically isolated grains with size below 10 nm. The magnetic grain isolation can be controlled by the amount of additional non-magnetic element in the system which determines the interparticle separation and therefore the interparticle interactions. Recently, much research work has been done on various non-magnetic matrices. Preliminary studies showed that the samples prepared in B$_2$O$_3$ and Carbon matrices have shown strong perpendicular anisotropy and fine grain size down to 4nm, which suggest these nanocomposite films are very promising and may lead to the realization of a magnetic medium capable of recording densities beyond 1 Tb/in$^2$. So, in this work, the effect of Carbon doping on the magnetic properties of FePt nanoparticles were investigated.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.960-966
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• 2013

In this study, operation data from an actual plant in M city were analyzed to evaluate effects of water supply into sewage sludge on the co-incineration of municipal solid waste (MSW) and sewage sludge. Design capacity of the stoker incinerator is 50 m3/day. Maximum portion of sewage sludge in the total waste input was 20%. According to this research, moisture content increase up to 85% of sewage sludge could be possible by water supply on MSW input to the incinerator. Therefore, stable operation of incinerator could be achieved. As water was added into sewage sludge up to 85%, input quantity of sewage sludge to frequency (Hz) was similar to theoretical input. Also, it is concluded that stable management of incinerator without leachate combustion and damages of refractory bricks and castable could be achieved by the reduction of low heating value.

• Journal of Animal Science and Technology
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• v.62 no.1
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• pp.103-110
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• 2020

Quality characteristics of chicken emulsion sausage manufactured with various levels of NaCl and 9 times heated bamboo salt (0.3%, 0.6%, 0.9%, and 1.2% respectively) were examined. The pH value of chicken emulsion sausage was increase tendency with increasing amount of bamboo salt, on the contrary in case of NaCl sample were decrease tendency with increasing amount of NaCl. Both before and after heating, redness of chicken emulsion sausage with bamboo salt treatments were upward trend with increasing amount of bamboo salt. water holding capacity (WHC) of 1.2% NaCl sample was significantly higher than 0.3%-0.9% (p < 0.05), but 0.9%, 1.2% bamboo salt samples were significantly higher than 0.3, 0.6 % (p < 0.05). Water loss of 1.2% NaCl and 0.9% bamboo salt samples were significantly lower than other treatment (p < 0.05). Protein solubility values significantly increased amount of bamboo salt and NaCl (p < 0.05), and samples of 0.9% NaCl and 0.6% bamboo salt values show similar values. Cooking yield of samples were increased tendency with increasing amount of NaCl and bamboo salt. Also viscosity values of sample containing 1.2% bamboo salt sample showed higher viscosity than other treatments. These results show that containing 1.2% NaCl chicken emulsion sausage and 0.9% bamboo salt chicken emulsion sausage were similar physicochemical properties. Therefore, bamboo salt is suitable for manufacturing chicken emulsion sausage.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.92-98
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• 1982

The major objective of this study was to investigate the heat resistance of epoxy resin mortar. For this purpose, these tests of compressive and bending strength were accomp- olished with various heating temperature (40˚C, 60˚C, 80˚C, 100˚C, 120˚C), and with various mixing ratio (1: 2, 1: 4, 1: 6, 1: 8, 1:10, 1:12, 1:14). The exprimental resin was to be Epi-Bis type epoxy resin, which is widely used as construction materials. The results obtained are summarized as follows; 1. The variations of color tone started to begin at 60˚C, and it has come out very heavy at 120˚C. It was assumed that the decrement of weight resulted from carbonization were about 0.22% at 100˚C, and about 0.34% at 120˚C. 2. The compressive and bending strength were increased with temperature rise up to 80˚C, but these were made rapid decrease when the given temperature was over. And so, the mean decrement of compressive and bending strength at 120˚C reached up to 35.5% and 26.4%, respectively. 3. The regression equation between compressive and bending strength for epoxy resin mortar under heat exposure were obtained as follows; od=0. 371oc+39. 23 (r=0. 986) And the estimated value of bending strength was corresponded to about 37 percent in comparing with that of the compressive strength. 4. Consquently, the heat resistance temperature of epoxy resin mortar was to be around 80˚C, and it was generally very low values. But it was regarded that the epoxy resin mortar will not be difficult with materials of civil engineering works and agricultural structures.

• Clean Technology
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• v.14 no.2
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• pp.117-122
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• 2008

Theoretical analysis was conducted on the combustion and the NOx formation characteristics of the coal-derived synthetic gases with medium-BTU heating value. The synthetic gas was assumed to contain the major species of CO, $H_2,\;CO_2$, and $N_2$ and the minor species of $CH_4$ and $NH_3$. Through thermochemical analysis on the combustion of the synthetic gas, the flame temperature, major and minor species of exhaust gas, and thermal and fuel NOx emissions were computed. In addition, the effects of the $CH_4$ and the $NH_3$ components in syngas fuel on combustion and NOx emission were investigated. Based on the computed results on the synthetic gases, basic direction and guidelines were provided fur the low NOx design of gas turbine combustor.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.97-105
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• 1998

20mol% Gd-doped CeO2 ultrafine powders as a promising electrolyte for the low temperature solid ox-ide fuel cells were synthesized with particle sizes of 15-20 nm using glycine nitrate process(GNP) fol-lowed by sintering their pellets at 150$0^{\circ}C$ for various times in air and then the electrical properties of the sintered pellets were investigated. The sintering behaviors and electrical properties for the sintered 20 sintered mol% Gd-doped CeO2 pellets were analyzed using dilatometer and SEM and AC two-terminal impedance technique respectively. As the heating temperature increased the synthesized powder had the sintering behaviors to show the start of the significant shrink at temperature of about $700^{\circ}C$ and to show the end of the shrink at the temperature of about 147$0^{\circ}C$. When the pellets were sintered with the vaious times at 150$0^{\circ}C$ the temperatuer which the shrink had been already completed the grain sizes in the sintered 20 mol% Gd-doped GeO2 pellets increased with the increase of the sintering time but their electrical resis-tivities showed the minimum value at the sintering time of 10h. It is due that the pellet sintered for 10h had the minimum activation energy fior the electtrical conduction. Thus it is thought that the decrease of the activation energy with the increase of the sintering time to 10h is induced by the enhanced mi-crostructure like the decrease of pore amount and the grain growth and its increase with the sintering times more than 10h is induced by the increase of the amounts of the impurities such as Mg. Al and Si from the sintering atmosphere.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.3
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• pp.227-235
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• 2012

Finding an alternative fuel and reducing environmental pollution are the main goals for future internal combustion engines. The purpose of this study is to obtain low-emission and high-efficiency by hydrogen enriched LPG fuel in constant volume chamber. An experimental study was carried out to obtain fundamental data for the combustion and emission characteristics of pre-mixed hydrogen and LPG in a constant volume chamber (CVC) with various fractions of hydrogen-LPG blends. To maintain equal heating value of fuel blend, the amount of LPG was decreased as hydrogen was gradually added. Exhaust emissions were measured using a HORIBA exhaust gas analyzer for various fractions of hydrogen-LPG blends. The results showed that the rapid combustion duration was shortened, and the rate of heat release elevated as the hydrogen fraction in the fuel blend was increased. Moreover, the maximum rate of pressure rise also increased. These phenomena were attributed to the burning velocity which increased exponentially with the increased hydrogen fraction in the $H_2$-LPG fuel blend. Exhaust HC and $CO_2$ concentrations decreased, while NOX emission increased with an increase in the hydrogen fraction in the fuel blend. Our results could facilitate the application of hydrogen and LPG as a fuel in the current fossil hydrocarbon-based economy and the strict emission regulations in internal combustion engines.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.9
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• pp.583-589
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• 2012

The various promotion countermeasures such as solidification, carbonization, and the creation of cement materials have been considered to existing treatment methods such as incineration and the creation of composts, since direct landfill was prohibited for encouraging the recycling based on the sludge treatment on land. The Main objective of this study is to investigate the feasibility of co-incineration for MSW (Municipal Solid Waste) and SS (Sewage Sludge) through the change of heat and atmospheric pollutants. In this study, LHV (Low Heating Value) is 100~300 kcal/kg because the MC (Moisture Content) of de-hydrated sewage sludge is approximately 80%. From the results, we knew the feasibility of co-incineration for MSW (80%) and SS (20%). As the co-incineration rate of SS up to 20% became higher, the loading of heat and atmospheric pollutants was not influenced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.9-13
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• 2019

In this study, a miniature thin film-patterned heater was fabricated on a silicon substrate using semiconductor process technology and the thermal characteristics of the applied voltage, power, and temperature of the thin film heater were measured and analyzed. The temperature of the thin film pattern heater increased with increasing power, but the temperature increase rate was gradual at high power intervals. The characteristics of the high temperature section of the platinum thin film-patterned heater were analyzed using the heat resistance model under atmospheric and vacuum conditions. The thermal resistance measured in a vacuum atmosphere was 0.79 [K/mW] higher than the heat resistance value 0.69 [K/mW] in air. The temperature of the thin film pattern heater can be maintained at a low power in a vacuum rather than in air, and these results are expected to be utilized in the structural design of a thin film-patterned heater element.