• 한국대기환경학회지
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• 제31권5호
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• pp.461-471
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• 2015

Base on emission factors derived from National Institute of Environmental Research, Particulate matter from combined cycle power plants (CCPPs) has been estimated to be a important source of $PM_{10}$. Generally there is no serious emission of particulate matter in CCPPs. because the fuel of them is natural gas. But emission gas after long shut down season has very high dust content. Therefore $PM_{10}$ emission rate is dependent on its operation mode. In this study, particulate dispersion study for new city near CCPPs complex has performed using CALPUFF model for three case. $PM_{10}$ concentration has big difference between normal operation and 2 case start-up condition after long shutdown. In normal operating conditions, daily $0.32{\sim}0.50{\mu}g/m^3$ influence on of the surrounding area. But when 1~2 aerobic high concentration discharged conditions, average concentration is higher about $9.2{\sim}34.1{\mu}g/m^3$ than normal operating conditions.

• Journal of Radiation Protection and Research
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• 제27권3호
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• pp.171-179
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• 2002

대기 중으로 방출된 방사성물질의 이동 확산 현상을 이해하기 위하여 3차원 장거리 확산 모델이 개발되었다. 모델은 수평방향으로 방출점으로부터 수천 키로 미터의 거리까지 공기중 농도와 지표면 침적을 계산하도록 설계되었다. 수직 난류운동은 혼합층 내와 혼합층 위로 분리하도록 고려하였다. 시험계산은 동북 아시아권의 영역을 고려하였고, 방출점은 중국의 동쪽 지점을 가정하였다. 계산된 농도분포는 바람장에 의해 방출점의 남동방향을 향해 주로 이동되었다. 개발된 모델은 원전 사고시 방사선 피해를 추정하기 위하여 이용될 것이며, 모델은 장거리 야외확산실험의 자료를 이용하여 비교 검증 연구를 통하여 보완될 것이다.

• 한국환경과학회지
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• 제1권1호
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• pp.35-43
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• 1992

Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are "A" and "B" at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.al dispersion model.

• 대한환경공학회지
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• 제28권12호
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• pp.1316-1322
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• 2006

본 연구는 천안 제 2산업단지에서 배출되는 대기오염물질과 악취물질을 분석하고 대기오염물질의 확산모델링을 수행하고자 함을 목적으로 한다. 측정은 12가지 지정 악취물질과 대기오염물질의 농도에 대하여 2005년 8월에 수행하였다. 악취물질은 주요 배출원을 중심으로 부지경계선에서 측정 및 분석을 실시하였으며, 대기오염물질은 ISCST3모델을 이용하여 대기오염확산 농도를 계산하였다. Air Master는 현재 국내 대기환경영향평가에 많이 사용되고 있고 U.S. EPA의 추천모델인 ISC3모델 중 ISCST3모델을 사용하였다. 따라서 천안 제 2산업단지를 대상으로 하절기 대기오염물질을 측정하여 모델링 하고 악취물질은 시료채취 후 분석을 실시하여 주변 지역에 영향을 끼치는 대기오염물질과 악취발생물질의 종류와 발생 원인을 규명하고자 한다.

• 대한토목학회논문집
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• 제30권4A호
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• pp.343-352
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• 2010

최근에 탄산화 콘크리트 구조물의 정량적인 사용수명과 장기적인 성능을 확보하고 예측하기 위해서 확률론적인 내구성 해석 및 설계를 수행하는 연구가 많이 진행되고 있다. 이와 관련하여 콘크리트 구조물에 확률론적 내구성 설계 개념을 도입되고 있다. 본 논문에서는 탄산화 콘크리트 구조물의 통계적인 자료를 이용하여 Fick의 첫 번째 법칙에 근거한 탄산화 예측 모델에 적용하였으며, 이를 이용하여 확률론적 내구성 해석을 수행하였다. 이 예측모델에 관련된 설계변수인 $CO_2$ 확산계수, 대기중의 $CO_2$ 농도, $CO_2$ 흡착량, 시멘트 수화도 등의 영향을 검토하였다. 확률론에 기초한 탄산화 예측모델은 여러 환경에 위치한 콘크리트 구조물에 모니터링 자료를 이용하여 탄산화 깊이와 잔존수명을 예측하였다. 그 결과로 본 연구에서 합리적인 탄산화 예측모델을 이용한 적용 방법은 탄산화 콘크리트 구조물의 내구성 확보 및 구조물의 손상 개시시기를 예측하고 구조물을 유지 관리하기 위한 유연한 의사결정을 할 수 있을 것으로 판단된다.

• 한국전산유체공학회지
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• 제6권4호
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• pp.1-7
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• 2001

Wind flow perturbations, recirculations and turbulence generated by buildings often dominate air pollutant distributions around buildings. This paper describes dispersion of contaminants in the vicinity of a building by solving the concentration equation based on previously simulated wind flow field. Turbulence closure is achieved by using the standard k-ε two-equation model. The paper shows application of the CIP method for solving a species concentration equation of contaminant gas around a rectangular building for two different sources under conditions of neutral atmospheric stratification. Results have been compared to the experimental data and the previous numerical results by hybrid scheme. The computational results of concentration profiles by the CIP method agree well with experimental data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.723-728
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• 2001

Wind flow perturbations, recirculations and turbulence generated by buildings often dominate air pollutant distributions around buildings. This paper describes dispersion of contaminants in the vicinity of a building by solving the concentration equation based on previously simulated wind flow field. Turbulence closure is achieved by using the standard k-e two-equation model. The paper shows application of the CIP method for solving a species concentration equation of contaminant gas around a rectangular building for two different sources under conditions of neutral atmospheric stratification. Results have been compared to the experimental data and the previous numerical results by hybrid scheme. The computational results of concentration profiles by the CIP method agree well with experimental data.

• 한국염색가공학회지
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• 제13권6호
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• pp.33-33
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• 2001

The physical properties and the dyeability of the easily dyeable polyester yarn(EDY) were investigated and compared with those of regular polyester (REG-PET). The EDY, copolymerized with small amount of polyethylene glycol(PEG), showed higher intensity of aliphatic CH peak in IR spectrum, lower density and lower compactness than those of the REG-PET from the analysis of IR, density gradient column and XRD respectively. In the physical properties, the EDY has lowers $T_g,\;T_m$, specific stress and initial modulus, and also has higher strain than that of the REG-PET. The EDY can be dyed under atmospheric pressure and its dyeing rate was faster than REG-PET due to low $T_d$, and this seems to be caused by the increased flexibility of Polymer chain in amorphous region of the EDY due to the copolymerization of PEG.ns being within the experimental error, the average values of lifetim.
$\tau$(t) are taken for further calculations. Rate constants such as Stern-Volmer quenching constants K$_{sv}$, quenching rate parameters k$_q$ and k''$_q$, static quenching constant V and kinetic distance r are determined using the modified Stern-Volmer eq.
tion and sphere of action static quenching model. In order to see whether the reactions are diffusion limited, equations k$_q$ = e$^{-Eq/RT}$ and k''$_q$ = e$^{-Eq/RT}$ are used to determine the values of E$_q$ and E''$_q$, the activati.
energies for collisional quenching and the values of E$_q$ are 14.53, 17.28 and 16.20 kJ mole$^{-1}$ for MPNO1, MPNO2 and 2-PI respectively and the values of E''$_q$ are 14.62 and 17.73 for MPNO1 and MPNO2 respectively. From the magnitudes of various quantities it has.
een concluded that the reactions are diffusion limited and the observed positive deviations in the S-V plot are due to static and dynamic quenching.

• Journal of Advanced Marine Engineering and Technology
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• 제37권8호
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• pp.807-815
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• 2013

대기압에서의 층류 에틸렌 확산 화염 내 매연 생성에 대하여 부력의 영향에 대한 보다 나은 이해를 위해 0g와 1g 조건하에서 수치해석을 수행하였다. 수치해석을 위하여 가스상 메커니즘과 열 및 이송특성을 이용하였다. 매연의 생성과 성장 및 산화에 대하여 예측하기 위하여 간단한 매연 모델이 채택되었으며 이 모델은 가스상과 매연의 화학적 상호작용에 고려되었다. 수치 결과로서 보다 두꺼운 확산층과 축방향 속도의 감소로 인해 0g에서의 화염이 1g하의 화염보다 더 넓은 화염을 가진다는 알 수 있었다. 0g에서의 축방향 속도의 감소는 더 긴 체류 시간을 가지게 하고 그 결과로 더 많은 매연 체적분율을 나타나게 한다. 0g 하에서는 화염이 부력으로 인한 불안정성이 없어져 화염의 흔들거림이 사라졌다.

• 설비공학논문집
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• 제16권10호
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• pp.942-951
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• 2004

This paper presents the results of a theoretical study of the effect of radiation during free convective laminar film boiling for methanol/water binary mixtures on an isothermal vertical wall at atmospheric pressure. With the well-known boundary layer theory as a basis, a theoretical model has been formulated into consideration for mass diffusion at liquid phase. The equations are numerically solved by a similarity method to investigate the effects of radiation emissivity on the surface with various parameters such as wall superheat and composition of more volatile component at liquid phase far from the wall. From the results, the distributions of the physical quantifies are investigated in both phases. New correlations are proposed to predict the heat transfer coefficient of binary mixtures. It is shown that the proposed correlations are in good agreement with numerical results and with Bromley's correlation within maximum $11\%$ errors. It is also found that as the wall superheat is increased, radiation effect becomes more important.