• Journal of the Korean Society of Combustion
• /
• v.21 no.4
• /
• pp.39-47
• /
• 2016

The aims of this research were to investigate combustion characteristics of lab-scale pressurized oxy-fuel combustion(POFC) system. In this study, the reactor, 800 mm long, was equipped with co-axial burner. Low calorific value syngas that is composed of mainly CO and $H_2$ was used as fuel whereas pure oxygen was used as an oxidant. Thermal heat input to the reactor varied from 2.6 kW to 6.1 kW. The reactor pressure also increases from atmospheric up to 15 bar. The results show that as the pressure increase, the temperature of reactor decreases on the whole in all cases. A significant temperature drop was observed especially at the bottom section of the reactor that exist flame. In addition, the flame instability increases as the pressure increases. Furthermore $NO_x$ emissions increases from atmospheric up to 2 bar. However beyond 2 bar, $NO_x$ emission reduces as pressure increases. Lastly $NO_2$ ratio in $NO_x$ also increases as pressure increases.

• Clean Technology
• /
• v.25 no.3
• /
• pp.245-255
• /
• 2019

Pressurized oxy-fuel combustion is a promising technology for $CO_2$ capture with a benefit of improving power plant efficiency compared with atmospheric oxy-fuel combustion. Prior to $CO_2$ compression in this process, a flue gas condenser (FGC) is used to remove $H_2O$ while recovering the latent heat. At the same time, the FGC has a potential for high-efficiency removal of $SO_x$ and $NO_x$ by exploiting their good solubility in water. In this study, experiments were carried out in a lab-scale, direct contact FGC under different pressures varying between 1 and 20 bar to evaluate the removal efficiency of $SO_2$ and $NO_x$ for individual gases and their mixture. In the tests for individual gases, 20% and 76% of $NO_x$ was removed at 1 bar and 10 bar, respectively. Even higher removal efficiencies were achieved for $SO_2$, and also these were maintained for longer as the pressure increased. In the tests for $SO_2$ and $NO_x$ mixture, the removal efficiency of $NO_x$ increased from 13% at 1 bar to 56% at 20 bar because of higher solubility at elevated pressures. $SO_2$ in the mixture was initially dissolved almost completely and then increased by 1,219 ppm at 1 bar and by 165 ppm at 20 bar. Overall, the removal efficiency of $SO_2$ and $NO_x$ was increased at elevated pressures, but it was lower in the mixture compared with individual gases at identical conditions because of a lower pH and associated chemical reactions in water.

• Advances in Traditional Medicine
• /
• v.2 no.2
• /
• pp.119-124
• /
• 2002

Cigarette smoking contributes to lung cancer, cardiovascular diseases, oral diseases, etc. In desire to reduce their risk of disease, many cigarette smokers have tried to quit smoking. Sensory aspects of cigarette smoke are important for providing smoking satisfaction. Previously it was reported that citric acid aerosol significantly reduced craving for cigarettes and enhances smoking reduction and cessation. In this study, we tested whether a newly combined product Ciga-X, an aerosol for cessation aid, had toxicity in human embryonic lung fibroblast (MRC-9). The inhibitory effect of Ciga-X on cytotoxicity induced by cigarette smoke extract (CSE) or nicotine was examined in MRC-9, and craving for cigarettes and smorkers satisfaction after using Ciga-X was estimated. Ciga-X did not affect cell viability and had no toxicity in MRC-9. Ciga-X significantly inhibited not only CSE-induced cytotoxicity but also nicotine-induced cytotoxicity in MRC-9. One hundred and forty smokers rated the satisfaction for Ciga-X aerosol and craving reduction for cigarettes after using Ciga-X. The percentage of over 5 rating was 71.0% and 50.0% of subjects in satisfaction test for Ciga-X compared to their own brand and in craving reduction for cigarette, respectively. Besides, craving reduction for cigarette was highly correlated with the duration of smoking. Subjects have smoked under 10 years were more reduced in craving for cigarettes after using Ciga-X as compared to over 10 years (p=0.049). These results suggest that Ciga-X may be effective in promoting smoking abstinence with the reduction of CSE- or nicotine-induced human lung fibroblasts cytotoxicity.

• Journal of Environmental Science International
• /
• v.14 no.2
• /
• pp.221-230
• /
• 2005

Catalytic wet oxidation of trichloroethylene (TCE) in water has been conducted using $TiO_2-supported$ cobalt oxides at $36^{\circ}C$ with a weight hourly space velocity of $7,500\;h^{-1}.\;5\%\;CoO_x/TiO_2$, prepared by using an incipient wetness technique, might be the most promising catalyst for the wet oxidation although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. XPS spectra of both fresh and used Co surfaces gave different surface spectral features for each $CoO_x,\;Co\;2P_{3/2}$ binding energy for Co species in the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $CO_2TiO_4\;and\;CoTiO_3$. The used catalyst exhibited a 780.3-eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD patterns for $5\%\;CoO_x/TiO_2$ catalyst indicated that the phase structure of Co species in the catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present predominantly on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.

• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.1
• /
• pp.69-76
• /
• 2010

While increased use of motor cycles in the recent years for various demands could worsen air quality, only few studies have been conducted on estimation of emission factors and characterization of emissions from motorcycle. In this study, emissions from selected six models of motorcycle based on largest market share and production rate were investigated. To investigate gaseous and carbonaceous air pollutants, such as carbon monoxide (CO), total hydrocarbon (THC), nitrogen oxide ($NO_x$), elemental carbon (EC) and organic carbon (OC), total 124 motorcycles between 2003 and 2007 model year were tested with regulatory driving conditions, such as CVS-40 and CVS-47 mode. These motorcycles were further sub-categorized based on their displacement (< 50 cc, 50~150 cc, and $\geq$ 150 cc), type of stroke (2- and 4 strokes) and model year (2003~2005 and 2006~2007). Tested motorcycles with recent model year (2006~2007) exhibited less emissions of regulatory gaseous and carbonaceous air pollutants compared to old model year (2003~2005). Chemical analysis showed that CO present in highest concentration followed by THC and $NO_x$ for all tested motorcycles. Interestingly, two strokes motorcycle produced higher THC emission but less CO and $NO_x$ than those of four strokes. For all types of displacement and stroke, emission factors (gram per kilometer) of THC and CO except $NO_x$ with recent model year (2006~2007) showed decreased trend compared to old model year (2003~2005). In addition to this, due to mixed combustion between gasoline fuel and lubricant, two strokes motorcycle showed OC > EC emission trend.

• Journal of Sensor Science and Technology
• /
• v.8 no.6
• /
• pp.454-460
• /
• 1999

$LaCoO_3$ thick-films for gas sensing layers were prepared on alumina substrate by screen printing method. The sensitivities to $C_4H_{10}$, $NH_3$, NO and CO gases were investigated for different heat treatment temperatures of the films. Their structural properties were examined by X-Ray Diffraction measurements and SEM photographs. The sensitivity of $LaCoO_3$ thick-film to CO gas was much higher than those of $C_4H_{10}$, $NH_3$, and NO gases. The optimal heat treatment and operating temperatures were $800^{\circ}C$ and $150^{\circ}C$, respectively. The sensitivities of $LaCoO_3$ thick-films to 500ppm and 1250ppm CO gas were 72% and 95%, respectively.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.4
• /
• pp.543-550
• /
• 1998

From the power plant in a steel plant, environment pollutants such as $SO_x$, $NO_x$, CO and $CO_2$ are emitted by combustion reactions of the fuels which are by-product gases, oil and liquefied natural gas(LNG). To reduce the amounts of the pollutants, it is important to build a predictive model for the emission of the pollutants. In this paper, model that predict the amounts of generated pollutants for the used fuel is developed by using Gibbs free energy minimization method[1] with the temperature correction technique. For some data set, the calculation results from this model are compared with the real emission amounts of $SO_x$, $NO_x$, and the result of the calculation by both ASPEN PLUS which is a commercial simulation software. This model shows good results and can be applied to other power plants.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2375-2380
• /
• 2013

Two metal-organic frameworks based on the connectivity co-effect between rigid benzenedicarboxylic acid and bridging ligand have been synthesized $[Zn_2(3-NO_2-bdc)_2(4,4'-bpy)_2H_2O]_n$ (1), $[Co(3-NO_2-bdc)(4,4'-bpy)H_2O]_n$ (2) (where $3-NO_2-bdcH_2$ = 3-nitro-1,2-benzenedicarboxylic acid, 4,4'-bpy = 4,4'-bipyridine). The two novel complexes were characterized by IR spectrum, elemental analysis, fluorescent properties, thermogravimetric analysis, single-crystal X-ray diffraction and powder X-ray diffraction (PXRD). X-ray structure analysis reveals that 1 and 2 are two-dimensional (2D) network structures. Complex 1 and complex 2 belong to triclinic crystal with P-1 space group. The luminescence measurements reveal that two complexes exhibit good fluorescent emissions in the solid state at room temperature. Also, thermal decomposition process and powder X-ray diffraction of complexes were investigated.

• Journal of the Korean Magnetics Society
• /
• v.4 no.3
• /
• pp.263-271
• /
• 1994

We have produced $Co_{1-x}Pt_{x}(X\;=\;0.53\;and\;0.75)$ alloy films by DC magnetron sputtering at various substrate temperatures and sputtering pressures. Sputter-deposited Co-Pt alloy films showed a strong (111) texture, and the degree of (111) texture of the as-deposited film was found to depend on the substrate temperature and Ar pressure. However, we observed that the degree of (111) texture did not affect the magnetic properties. In addition, we have investigated the effect of heat-treatment on magnetic properties of these films. While the magnetic properties of the $Co_{0.25}Pt_{0.75}$ alloy films showed no noticeable changes, the coercivities and the squarenesses of the $Co_{0.47}Pt_{0.53}$ alloy films were drastically increased by annealing. Structural analysis using transmission electron microscopy(TEM) and x-ray diffractornetry(XRD) revealed that $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases, respectively, were formed, each with a strong (111) texture. By comparing the magnetic properties between $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases in relation to the atomic arrangements in a unit cell, we conclude that the magnetic anisotropy in the Co-Pt alloy system depends mainly on the atomic arrangements of Co and Pt.

• Journal of the Korean Chemical Society
• /
• v.64 no.6
• /
• pp.334-344
• /
• 2020

The adsorption of various atmospheric harmful gases (COx, NOx, SOx) on graphene-like Germanene 2D sheet was theoretically investigated using density functional theory(DFT) method. The structures were fully optimized at the B3LYP/cc-pvDZ and CAM-B3LYP/cc-pvDZ levels of theory and confirmed to be a local minimum by the calculation of the harmonic vibrational frequencies. The adsorptions of gases on the Germanene sheet were predicted to be a physisorption process for CO, CO2, NO, and SO2 gases but to be a chemisorption process for NO2, SO, and SO2 gases.