• 한국가시화정보학회지
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• 제18권2호
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• pp.18-27
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• 2020

Air lift pump operated by buoyancy is mainly used for the continuous circulation and the purification of fluids. In this study, the computational flow analysis has been performed with the geometric and operating conditions of the air lift pump. The numerical data from the analysis have been verified by comparing with the previous experimental data. The following results are obtained which advance the efficiency of the air lift pump. As the submergence length of pipe increases and the pipe length over the water surface decreases, the non-dimensional mass flow ratio increases in both cases. When the position of the air injection hole is within the pipe, the circulation range of the surrounding fluid becomes widened with the distance between the air injection hole and the pipe inlet relatively becoming narrower. It is more efficient both when the air injection velocity is at 10 m/s and at 15 m/s, and when the diameter of the pipe with holes is doubled near the water surface. It is expected that these results can be provided as fundamental data for operating the air lift pump.

• 한국대기환경학회지
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• 제24권1호
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• pp.108-121
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• 2008

On January 1, 2005, the Korean Ministry of Environment put into operation a comprehensive program, so called 'Blue Sky 21' project, for the improvement of air quality in greater Seoul metropolitan area. This program was legally based on the 'Special Act on Metropolitan Air Quality Improvement' for Greater Seoul area, which was established in 2003, and should be updated every 10 years. The principal objective of this program is to improve the air quality in Seoul and surrounding area by 2014 to the levels of air quality in Tokyo and Paris, with particular emphases on reducing the concentrations of nitrogen dioxide and $PM_{10}$. Any regulation of the emission of toxic air pollutants in general, and $NO_2$ and $PM_{10}$ in particular, should be based on human exposure levels and consequential health effects. In this article, the contents and feasibility of the special program were critically evaluated with respect to the reduction of health risks. Important issues for improving not only air quality but public health are discussed, and future requirements for the success of the special program are suggested.

• 한국대기환경학회지
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• 제4권1호
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• pp.79-83
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• 1988

To improve working environment for the toll workers who were working at Kyungbu expressway in outskirts of Seoul and Suwon, the status of air pollution surrounding toll booth were measured from March 28 through June 14, 1986. The results were as follows: 1. The amount of TSP (total suspended particle) surrounding toll booth was directly proportional to the traffic load. The ratio of traffic load at Seoul and Suwon toll was 3.2:1 and of TSP was 2.6:1. 2. The proportion of particle larger than 5$\mum$ was 24.8 $\sim$ 34.9% of TSP at Seoul toll and 19.2 $\sim$ 32.7% at Suwon. The proportion of particle less than 2$\mum$ was 38.7 $\sim$ 51.8% of TSP at Seoul toll and 34.8 $\sim$ 54.8% at Suwon. 3. The concentration of respirable particle les than 7$\mum$ measured by personal air sampler was higher in Seoul toll booth than that of Suwon and it seems to be influenced by the exhausion of diesel engine. Especially the concentration of respirable particle of reformed toll booth with air curtain was 20% lower than unreformed one. 4. Concentration of Pb among suspended particles around Seoul toll was 5 times higher than Pb of Suwon toll. So it is considered that there were other possible pollution source of Pb beyond heavy traffic in Seoul toll area. The amount of Pb inside toll booth was extremely small but the concentration of benzo(a)pyrene showed a trend of increase according to traffic stagnation. 5. The concentration of $SO_2$ arround toll showed no difference between weekday and weekend and also showed no relation with traffic load. But the concentration of $NO_2$ was affected by traffic load.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.205.2-205.2
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• 2010

Optimum operation conditions of low-NOx MILD combustion for gaseous and solid fuels have been investigated by experimental and computer simulation. Loop reactor type MILD combustor without air pre-heater has been used in the present work. The results show that the balance of injection velocities of fuel and surrounding air is major factor for maintaining MILD combustion mode. Temperature difference between lower and upper part can be reduced less than 20 degree of Celsius. It was found that NOx emission in MILD combustion also can be remarkably reduced to more than 85% in comparison with conventional premixed combustion, and reduced to more than 50% in case of nitrogen and carbon dioxide carrying dried waste water sludge and pulverized coal in comparison with the same of air carrying. It was also found that carbon monoxide emission increase was not appeared at the time of changeover to MILD combustion mode from premixed or air carrying combustion at optimum operation condition.

• 한국환경과학회지
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• 제8권4호
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• pp.485-490
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• 1999

We will calculate concentration of air pollutants using ISCST3, FDM and AERMOD of models recommended in U. S. EPA which are able to predict concentration of short term for point source, complex like industrial complex, power plant and burn-up institution. Before executing model, as analyzing computational result of many cases according to selecting of input data, we will increasing predictable ability of model in limit range of model. Especially, we analyzed three cases-case of considering various emission rate according to time scale and not, case considering effect of atmospheric pollution materials removed by physical process. In our study, after comparing and analyzing results of three model, we choose the atmospheric dispersion model reflected well the characteristic of the area. And we will investigate how large the complex pollutant sources such as industrial complex contribute to atmospheric environment and air quality of the surrounding the area as predicting and estimating chosen model.

• International Journal of Safety
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• 제3권1호
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• pp.20-26
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• 2004

The system considered in this model consists of a single, semi- transparent, diesel fuel droplet, which is immobile in the heating area and surrounded by a quiescent air. A uniform external radiation field surrounds the droplet. Results from mathematical simulation suggest that because of the higher surface temperature, the external radiative heating of the droplet can promote an earlier ignition of the fuel vapour/air mixture. The radiative heating of the droplet increases the mass transfer from the droplet to the surrounding gas-phase, thus, decreasing the heterogeneity of the fuel droplet/air system.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.68-75
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• 2002

The dynamic behaviors of the single vortex and flame-vortex interaction in a $CH_4/Air$ diffusion flame with addition of $CO_2$ were investigated numerically. The numerical method was based on a predictor-corrector for low Mach number flow. A two-step global reaction mechanism was adopted as a combustion model. Through comparison of results by effect of $CO_2$ added either on the fuel or oxidizer side, it was found that the growth of single vortex and entrainment of surrounding fluid by $CO_2$addition on the fuel side are larger than those by $CO_2$ addition on oxidizer side. Also, when $CO_2$ is added on fuel side, flame-vortex interaction becomes more significant than on air side.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.233-234
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• 2006

LNG is extremely cold, $-160^{\circ}C$ in its liquid state. When it vaporizes, returning to its natural state (re-vaporization), it cools its surroundings. This is cold energy. The manufacturing of liquid air is the first processes developed as the most effective utilization of LNG cold. In this paper, adopting the LNG cold process for manufacturing liquid air was developed and analysed. The result showed that as the higher air pressure and adapting nitrogen precooling, liquefaction rate and cumulative mass was increased.

• 한국환경과학회지
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• 제9권1호
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• pp.65-74
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• 2000

In this study, we investigated the site feasibility for the construction of the incineration facilities in Won Ju City. To assess the environmental impact of its construction, we examined the current status of air quality in the selected candidate sites and predicted the extent of air quality change upon its operation through modification of stack type. If the stack height is assumed to be 70 m, the concentrations of $SO_2$ and dioxin in the surrounding area were predicted to increase by 0.05 ppb and 0.09 pg/$m^3$, respectively. The impact of its operation was assessed and compared among different sites. According to this analysis, more impact was expected from the residential area for the Dan-Gye site than from agricultural areas of the Kwan-Sul and Sa-Je site.

• 한국환경과학회지
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• 제30권11호
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• pp.967-977
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• 2021

From January 1, 2020, the International Maritime Organization has implemented a global regulation, known as IMO 2020, to reduce the sulfur content in fuel oil of ships from 3.5% to 0.5%. In this study, we used data from air monitoring stations to evaluate the change in air quality at New Port and North Port in Korea areas after the regulation was implemented. The concentration of SO₂ and NO₂ was higher in the port areas than in the surrounding areas due to exhaust gas from ships and vehicles. However, the SO₂ concentration decreased by more than 50% in the port area, demonstrating the efficiency and positive effect of the IMO 2020 sulfur limit.