• 한국대기환경학회지
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• 제8권4호
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• pp.229-239
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• 1992

A receptor model application was performed by using a chemical mass balance (CMB) model to identify and apportion the specific source of airborne organic pollutants, particularly polynuclear aromatic hydrocarbons (PAHs). Source profiles of PAHs produced from the combustion of fossil fuels for CMB modeling were prepared by measuring them in emission gases. The emission sources which were examineed for the development of PAH source profiles are a coal-fired furnace using Yontan, a bunker-C iol heating boiler, and gasoline-and diesel engine automobiles. The ambient concentrations of PAHs were determined at four sites in Daejon city in 1991 with a seasonal variation. Wintertime air samples contained more extractable organic matter than summertime samples. The results of CMB modeling were various depending on the sampling sites and seasons, but the emission from bunker-C oil heating boliers was the predominant factor to affect local air quality throughout the year.

• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.43-50
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• 2007

Reheating furnace is an essential facility of a rod mill plant where a billet is heated to the required rolling temperature so that it can be milled to produce wire. Although it is very important to obtain information on billet temperatures, it is not feasible during furnace operation. Consequently, a billet temperature profile should be estimated. Moreover, this estimation should be done within an appropriate time interval for an on-line application. In this paper, a billet heat transfer model based on 2D FEM(Finite Element Method) with spatially distributed emission factors is proposed for an on-line billet temperature estimation and also a measurement is carried out for two extremely different furnace operation patterns. Finally, the difference between the model outputs and the measurements is minimized by using a new optimization algorithm named uDEAS(Univariate Dynamic Encoding Algorithm for Searches) with multi-step tuning strategy. The obtained emission factors are applied to a simulation for the data which are not used in the model tuning for validation.

• 천문학논총
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• 제15권spc1호
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• pp.113-118
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• 2000

A magnetic cataclysmic variable has a rotating magnetic white dwarf which accretes matter from its late type companion. Kim & Beuermann (1995) presented a phenomenological model of the accretion from its surrounding structure e.g., a disk into the magnetosphere of the white dwarf, and presented results for the spin modulated X-ray spectrum and light curves. Using this model, we calculate the optical continuum and line emission which result from reprocessing of X-rays in the accretion stream within the magnetosphere. Penning (1985) suggested the observed spin-modulated radial-velocity variations might result from reprocession of X-rays in the disk. We, however, find the radiation can be originated from the magnetosphere accretion stream. We use the same geometrical model to calculate the optical and the X-ray behaviour. The results from the two wavelength bands are internally consistent. We conclude that this approach will increase the diagnostic accuracies of the results.

• 환경영향평가
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• 제5권1호
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• pp.69-77
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• 1996

The variations of ozone concentration and the sensitivity test for VOC emission intensities was investigated by means of a PBM(Photochemical Box Model). Compared to monitoring data, the typical variations of $NO_2$, CO, $O_3$ for days were successfully reproduced. Model results revealed that maximum ozone concentration got increased with the increase of VOC emission, that is, VOC played the important role in producing the photochemical smog.

• 대한교통학회지
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• 제29권6호
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• pp.117-128
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• 2011

본 연구에서는 교통사업 시행에 따른 대기질 평가의 객관성 향상을 위하여 장래 도로이동오염원의 배출계수 예측 모형을 구축하였다. 이를 위해 자동차의 연식별 차량대수 자연감소 패턴을 분석한 후, 차령별 열화계수 등을 활용하여 2015년과 2030년의 속도별 배출계수 예측모형을 정립하였다. 본 연구에서 예측한 2030년 기준의 배출계수는 현재 교통 분야에서 적용하고 있는 배출계수와 비교해 볼 때, 운행속도 30km/h의 경우에 승용차와 버스/트럭 각각 5%~37%, 8%~83% 정도 낮은 것으로 분석되었다. 이러한 실험 분석결과는 통계적으로 유의미한 것으로 판정되었으며, 이를 통해 교통사업 시행에 따른 대기질 평가를 위한 본 모형의 유용성을 확인하였다.

• 환경영향평가
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• 제16권1호
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• pp.1-13
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• 2007

This study was carried out to estimate the emission reduction rates for the regional allowable emissions by special measures to achieve the target air quality in Seoul Metropolitan Area (SMA). A modeling system was designed to validate the details in enforcement regulations set up by local governments based on the current status and plans for air quality improvement. Modeling system was composed of meteorological model (MM5), emission model (SMOKE), and air quality model (CMAQ). Predicted results by this system show quiet well not only daily air pollutants concentration but also the tendencies of wind direction, wind speed and temperature. To achieve the target air quality in Seoul Metropolitan Area (SMA), emission allowances are estimated by seasons and regions. Referring to the base year 2002, it was estimated that emission reduction rates to achieve the intermediate goal in 2007 were 14.2% and 16.6% for NOx and $PM_{10}$, respectively. It was also estimated that 52% of NOx and 48% of $PM_{10}$ reductions from the base year 2002 would be required to accomplish the air quality improvement goal of 22 ppb for $NO_2$, and $40mg/m^3$ for $PM_{10}$ in year 2014. To improve $NO_2$ and $PM_{10}$ concentration through emissions reduction policies, it was found that emissions reduction for the on-road mobile sources would be the most effective in SMA.

• 한국경제지리학회지
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• 제16권2호
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• pp.149-166
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• 2013

본 논문은 중국의 가구부문에서의 주거 에너지 소비에 따른 이산화탄소 배출량의 지역 격차를 파악하고 지역격차에 영향을 미치는 요인을 추정하는 데 목적을 두었다. 2006~2011년 동안 30개 성급의 균형 패널 데이터를 토대로 1인당 이산화탄소 배출량을 종속변수로, 가구 특성 요인과 지역환경 특성 요인들을 설명변수로 하는 패널모델을 구축하였다. 모형의 추정 결과 가구 특성 중 대졸자 비율, 1인가구 비율, 여성경제활동비율, 노령인구 비율은 탄소 배출에 유의하게 영향을 미치는 것으로 나타났다. 또한 지역 특성 중 주거밀도가 높을수록 탄소배출량이 줄어드는 것으로 나타났다. 본 연구 결과는 중국에서 주거 에너지 소비로 인한 이산화탄소 배출량을 절감시키는 정책을 수립하는데 있어서 지역별 가구특성, 공급되는 에너지원, 그리고 지역의 기후특성에 따라 차별화되어야 한다는 정책적인 시사점을 제공하였다.

• 한국대기환경학회지
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• 제21권1호
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• pp.73-81
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• 2005

It is widely accepted that, at present, the SO$_2$ emissions in China are not increasing thanks to the rigorous Chinese government policies. However, with the development of western China, it is possible that the SO$_2$ emission amounts might increase in regional scale. In this study, changes of sulfur deposition pattern and unprotected ecosystem in east Asia due to the sulfur emission pattern changes in China are studied by using the RAINS-Asia model. Five scenarios have been postulated to understand the effects on east Asia, especially, on Korea and Japan. It is found that the increase of SO$_2$ emission in western China might increase the total emission in whole China. And the amount of sulfur deposition from western China on east Asia would be higher than those from eastern China. The deposition amount of sulfur species on Asia is 3.2 Mt when SO$_2$ are emitted from western China only while 2.6 Mt from eastern China only. Generally, Korea and Japan are influenced more by emissions from eastern China than western China. However, if the SO$_2$ emissions from western China increase by 100% while those decrease by 10% in eastern China compared to the base case, the deposition amount of sulfur species on Korea and Japan would be higher than the base case. The fraction of unprotected ecosystem in Korea and Japan for the base case are 50 and 5%. However, if the emissions from western China increase by 100% while those decrease by 10% in eastern China, the fraction of unprotected ecosystem in Korea and Japan would be 52 and 6%.

• 한국대기환경학회지
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• 제25권6호
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• pp.539-549
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• 2009

The purpose of this study is to estimate hourly Asian dust emission flux in springtime by using the optimized Weather Research Forecasting model (WRF) in order to accurately predict the horizontal flux of Asian dusts. Asian dust emission flux using 5 empirical formulas such as US EPA, Park and Inn, Wang, The Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Dust Entrainment and Deposition (DEAD) were calculated and compared by using classified land-use types and size distribution at various locations in China and Mongolia together with the hourly meteorological elements of the WRF model. As a result, the empirical formula in US EPA among them, which was considered the various conditions such as vegetation, soil type and terrain, was better than the other 4 empirical formulas. However, these formulas were adjusted hourly and vertically in time and space because there was different order and time resolution of dust emissions from original empirical formulas.

• 한국대기환경학회지
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• 제18권5호
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• pp.401-410
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• 2002

Concerns for energy conservation, environmental pollution, and the fact that organic wastes account for a major portion of our waste materials, have created the interest of biogas, which usually contains about 60 to 70 percent methane, 30 to 40 percent carbon dioxide, and other gases, including ammonia, hydrogen sulfide, mercaptans and other noxious gases. Cyclone combustors are used for homing a wide range of fuels such as low calorific value gas, waste water, sludge. coal, etc. The 3-dimensional swirling flow, combustion and emission in a tangential inlet cyclone incinerator under different inlet conditions are simulated using a standard k-s turbulence model and ESCRS (Extended Simple Chemically-Reacting System) model. The commercial code Phoenics Ver.3.4 was used for the present work. The main parameters considered in this work are inlet velocity and air to fuel ratio. The results showed that the change of operating conditions had an influence on the shape and size of recirculation zones, mixture fraction and axial velocity which are important factors for combustion efficiency and emission behavior. The application of this kind of computer program seams to be promising as a potential tool for the optimum design of a cyclone combustor with low emission.