• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.441-442
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.433-434
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.447-448
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.612-613
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• 2010

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.191-198
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• 2000

For a characterization of the pretreated waste automotive catalyst the following analysis techniques were applied : EA(Elemental Analysis) BET(Brunaure-Emmett-Teller) and ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry). The combustion activity of waste automotive catalyst was investigated for methanol acetaldehyde and toluene as model VOCs in a fixed bed reactor. carbon deposit amount was decreased with increasing catalyst showed a good catalytic activity for VOCs combustion at 40$0^{\circ}C$. Catalytic activity for methanol acetaldehyde and toluence combustion was very excellent and decreased with mileage. The catalytic activity of a waste automotive catalyst for methanol combustion increased after acid treatment. The acid effect of catalytic activity was summarized as follows: HNO3>HCI>H2SO4>CH3COOH. The waste automotive catalyst regenerated by the pretreatment method might have a excellent catalytic activity for VOCs combustion.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.3
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• pp.231-241
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• 1996

The effect of radiation and buoyancy on the thermophoresis phenomenon owing to the presence of highly absorbing, emitting particles (such as soot or pulverized coal) suspended in a two phase flow system was investigated numerically for a turbulent mixed convection flow. The analysis of conservation equations for a gas-particle flow system was performed on the basis of a two-fluid model from a continuum Eulerian viewpoint. The modified van Driest and Cebeci mixing length turbulence model was adopted in the anaylsis of turbulent flow. In addition, the P-1 approximation was used to evaluate the radiation heat transfer. As expected from the particle concentration and drift velocity distribution, the cumulative collection efficiency E (x) becomes larger when the buoyancy effect increases (i.e. higher Grashof number), while smaller as the radiation effect increases (i.e. higher optical thickness).

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E4
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• pp.169-175
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• 2003

The effect of gas composition on the discharge characteristics and the ozone production in silent discharge (SD) process was investigated. The major gas components, $N_2$, $O_2$, and $H_2O$ influence the discharge properties according to their relative magnitude of ionization thresholds and electron affinities. The generated amount of ozone increased with the discharge energy by increasing the electron mean energy. The higher oxygen content injected, the higher ozone produced. A small amount of water vapor significantly lowered the discharge onset voltage by the ionization threshold decreasing effect and high electrical conductivity. However, the further increase of water vapor contributes to decrease the electron density by the electron affinity The addition of water greatly reduced the ozone generation through the formation of OH radical and the catalytic ozone destruction process.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.821-830
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• 2006

To identify the effect of local air pollutants on the $PM_{2.5}$ level at Gosan, $PM_{2.5}$ composition data, continuous $O_3,\;NO_x,\;SO_2,\;CO$ data, VOCs data, surface wind characteristics, and backward trajectory analysis results were analyzed for the measurements in March 2000 during which high concentrations of mass and anthropogenic ionic species were reported. It was found that the combination of surface wind and continuous gaseous species data can help to identify local effect in Jeju Island. Even in a high $PM_{2.5}$ level case mainly affected by long range transport from China, it was Identified that local effects were also significant for both the duration and pollutants' levels.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.377-387
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• 1996

This study was carried out to monitor the visibility including measurement and analysis of the various parameters such as particle size distribution, chemical composition, and meteorotical conditions to understand the characteristics and causes of this phenomenon. According to the analysis of intensive sampling, $SO_4^{2-}, NO-3^-, Cl^-, NH_4^+$ ion concentration increased together with the mass concentration around 1 $\mu$m in the case of low visibility. $(NH_4)_2SO_4, NH_4NO_3$, and $NH_4Cl$ were thought to be the major components of fine particles. The statistical analysis showed that the scattering effect of particle was 81.2%, the absorption effect was 14.9%. Therefore, these effects were the major factors to reduce the visibility. In conclusion, the visibility was reduced by the fine particle of sulfate (18.6%), nitrate (14.2%), organic carbon (10.8%), element carbon (25.8%), and residual (24.8%) during this study.

• Structural Engineering and Mechanics
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• v.65 no.2
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• pp.191-201
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• 2018

The corrosion environments in a steel structure are significantly different depending on the individual parts of the members. To ensure the safety of weathering steel structures, it is important to evaluate the time-dependent corrosion behavior. Thus, the progress and effect of corrosion damage on weathering steel members should be evaluated; however, the predicted corrosion depth, which is affected by the corrosion environment, has not been sufficiently considered until now. In this study, the time-dependent thicknesses of the corrosion product layer were examined to quantifiably investigate and determine the corrosion depth of the corroded surface according to the exposure periods and corrosion environments. Thus, their atmospheric exposure tests were carried out for 4 years under different corrosion environments. The relationship between the thickness of the corrosion product layers and mean corrosion depth was examined based on the corrosion environment. Thus, the micro corrosion environments on the skyward and groundward surfaces of the specimens were monitored using atmospheric corrosion monitor sensors. In addition, the evaluated mean corrosion depth was calculated based on the thickness of the corrosion product layer in an atmospheric corrosion environment, and was verified through a comparison with the measured mean corrosion depth.