• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1190-1195
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• 2005

Biomass burning is a source of greenhouse gases, carbon dioxide, methane, and nitrous oxide. Under the ideal conditions of complete combustion, the burning of biomass produces carbon dioxide and water vapor. Since complete combustion is not achieved under any conditions of biomass burning, other carbon species, including carbon monoxide, methane, non-methane hydrocarbons and particulate carbon are produced. In this study, we analyze the combustion characteristics of rice-husk, such as heat release rate, smoke production rate, the percentage variation of CO and $CO_2$, oxygen consumption rate, and mass loss under different heat fluxes (20, 50 and 70kW). As a result, at 20kW incomplete combustion is occurred so that the percentage of CO is high in initial burning and total smoke release is higher than the others. At 50kW and 70kW, the combustion behaviors is very similar except the variation of CO percentage.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.32-37
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• 1998

The Carbon Dioxide is the gas, which causes green house effects, unusual changes in the weather, destruction of the life. Almost every nation in the world is trying to search the countermeasure to this poisonous gas. I synthesized $Fe_3O_4$ and NaOH, in order to decompose the Carbon Dioxide. Among the particles synthesizing $Fe_3O_4$, I chose the equivalent ratio 1.00 which can decompose the Carbon Dioxide best, and fixed that equivalent ratio and added the 0.005-3.00 mole percentage of NiCl$_2$ and synthesized $Fe_3O_4$. I studied the decomposition of the Carbon Dioxide and methanized reaction, by measuring its crystal structure, thermochemistrical character and specific surface area. In decomposing the Carbon Dioxide, I used oxygen-deficit Magnetite which I produced by injecting the hydrogen gas into the synthesized sample. I observed the methanization reaction by raising the temperature of sample up to 650$\circ$C and having it reacted with the hydrogen gas. The decomposition of the Carbon Dioxide was added 0.005, 0.03, 0.05 mole percentage of NiCl$_2$ was more effective than pure $Fe_3O_4$. All sample in which the decomposition of the Carbon Dioxide took place produced the methane gas.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.38-39
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• 2009

The precipitate percentage and the spheroidization percentage were analyzed as a function of the tempering temperatures and the alloying elements for high strength preheat-treated steel. The optimum temperature of tempering produced the small precipitates of nano size. The precipitate percentage and the spheroidization percentage were increased with the tempering temperatures. The size of precipitate decreased as the spheroidization of carbon precipitates progressed. The alloying elements such as Cr and Mo reduced the sphereidization temperature.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.68-74
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• 2016

In this study, the fabrication of zeolite combined activated carbon spherical samples was carried out as follows. Briefly, ZSM-5 zeolite and activated carbon were composed as main absorbent materials; by controlling the weight percentage of zeolite and binder materials, a series of spherical samples (AZP 4, 6, 8) were prepared. These spherical samples were characterized by BET, XRD, SEM, EDX, and pressure drop; benzene and iodine adsorption tests, bactericidal effect test, and ignition temperature test were also performed. The adsorption capability was found to depend on the BET surface area; the spherical samples AZP6 with high BET surface area of $1011m^2/g$ not only exhibited excellent removal effects for benzene (24.9%) and iodine (920mg/g) but also a good bactericidal effect. The enhanced ignition temperature may be attributed to the homogeneous dispersion conditions and the proper weight percentage ratio between zeolite and activated carbon.

• Advances in materials Research
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• v.6 no.3
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• pp.245-255
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• 2017

High energy ball milling is employed to produce iron matrix- multiwall carbon nanotube (MWCNT) reinforced composite. The damage caused to MWCNT due to harsh ball milling condition and its influence on interfacial bonding is studied. Different amount of MWCNT is used to find the optimal percentage of MWCNT for avoidance of the formation of chemical reaction product at the matrix - reinforcement interface. Effect of process control agent is assessed by the use of different materials for the purpose. It is observed that ethanol as a process control agent (PCA) causes degradation of MWCNT reinforcements after milling for two hours whereas solid stearic acid used as process control agent, allows satisfactory conservation of MWCNT structure. It is further noted that at a high MWCNT content (~ 2wt.%), high energy ball milling leads to reaction of iron and carbon and forms iron carbide (cementite) at the iron-MWCNT interface. At low percentage of MWCNT, dissolution of carbon in iron takes place and the amount of reinforcement in iron matrix composite becomes negligibly small. However, under the present ball milling condition (ball to metal ratio~ 6:1 and 200 rpm vial speed) iron-1wt.% MWCNT composite of good interfacial bonding can retain the tubular structure of reinforcing MWCNT.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.79-88
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• 2013

This study set out to evaluate the economy, environmentality, and complexity (economy+environmentality) of fire station buildings of public service facilities and propose ways to apply the optimization of renewable energy system to fire station buildings. As for economy according to life cycle costs, economy increased when the application percentage of the geothermal and solar heat system increased over the three renewable energy system types (geothermal, solar heat, and solar photovoltaic). On the other hand, economy decreased when the application percentage of the solar photovoltaic system increased. As for environmentality according to tons of carbon dioxide, environmentality decreased when the application percentage of the geothermal and solar heat system increased. Environmentality increased when the application percentage of the solar photovoltaic system increased. As for complexity (economy+environmentality) according to the weighted coefficient method, complexity increased when the application percentage of the geothermal system increased. It was highest at the combination of the solar heat system (20%) and geothermal system (80%). On the other hand, complexity decreased when the application percentage of the solar photovoltaic system increased. It was lowest at the combination of the solar photovoltaic system (80%) and geothermal system (20%).

• Carbon letters
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• v.10 no.1
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• pp.5-8
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• 2009

We measured the non-carbon content of single-walled carbon nanotubes (SWCNTs) in SWCNT soot using thermogravimetric analysis. The weight increased percentage by the oxidation of metal in the raw soot is well obtained by TGA graph which was confirmed with ICP-AES, XRD, and XPS. This work will be very useful for the purity precise evaluation of SWCNT with UN-vis-NIR spectroscopy.

• Journal of the Korean institute of surface engineering
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• v.32 no.2
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• pp.93-99
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• 1999

Surface polymer layer formed on the silicon wafer during the oxide overetching using $C_4F_8$/ helicon wave plasmas and their characteristics were investigated using spectroscopic elipsometry, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry. Overetch percentage and dc-self bias voltage were varied to investigate the effects on the characteristics of the polymers remaining on the overetched silicon surface. The increase of bias voltage from -80 volts to -120 volts increased the C/F ratio and carbon bondings such as C-C, $C-CF_x$/, and C-Si in the polymer while reducing the thickness of the polymer layer. However, the increase of the overetch percentage from 50% to 100% did not change the composition of the polymer layer and the carbon bondings in the polymer layer remained same even though it increased the polymer thickness. The polymer layer formed at the higher dc-self bias voltage was more difficult to be removed by the following various post-etch treatments compared to that formed at the longer overetch percentage.

• Carbon letters
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• v.14 no.1
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• pp.14-21
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• 2013

Physically and chemically activated carbons (ACs) exhibited high adsorption capacities for organic and inorganic pollutants compared with other adsorbents due to their expanded surface areas and wide pore volume distribution. In this work, seven steam-ACs with different burn-off have been prepared from cotton stalks. The textural properties of these sorbents were determined using nitrogen adsorption at $-196^{\circ}C$. The chemistry of the surface of the present sorbents was characterized by determining the surface functional C-O groups using Fourier transform infrared spectroscopy, surface pH, $pH_{pzc}$, and Boehm's acid-base neutralization method. The textural properties and the morphology of the sorbent surface depend on the percentage of burn-off. The surface acidity and surface basicity are related to the burn-off percentage. A theoretical model was developed to find a mathematical expression that relates the % burn-off to ash content, surface area, and mean pore radius. Also, the chemistry of the carbon surface is related to the % burn-off. A mathematical expression was proposed where % burn-off was taken as an independent factor and the other variable as a dependent factor. This expression allows the choice of the value of % burn-off with required steam-AC properties.

• Carbon letters
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• v.10 no.1
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• pp.23-32
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• 2009

The adsorption of phenolic compound resorcinol on activated carbons prepared from Moringa oleifera (Drumstick bark) has been investigated. Activated carbon was prepared by impregnating Moringa oleifera with 50% phosphoric acid in the ratio of 1:1 and 1:2(w/w), designated as MOAC1 and MOAC2. Equilibrium and isotherm studies were carried out. The influences of variables such as contact time, initial concentration of resorcinol, carbon dosage in the solution on percentage adsorption and adsorption capacity of the bark have been analysed. The equilibration time was found to be 4 h. Kinetics of resorcinol onto activated carbons was checked for pseudo first order and pseudo second order model. It was found that the adsorption of resorcinol follows pseudo second order kinetics for both MOAC1 and MOAC2. The isotherm data were correlated with isotherm models, namely Langmuir and Freundlich. Adsorption isotherms were satisfactorily fitted by both the Langmuir and Freundlich model for MOAC1 and MOAC2.