• Journal of Korean Society for Atmospheric Environment
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• v.11 no.3
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• pp.273-278
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• 1995

This study is to estimate the ventilation volume by the traffic that originated from driving automobiles for two tunnels (Kugi tunnel and Kumhwa tunnel) that adopted natural ventilation system among tunnels of Seoul, and on the basis of which, we estimated the ventilation velume at various conditions. With the result of the estimation, we will present the basic method that can be operated with the optimum condition for the ventilation system. Estimating the predicted ventilation volume in the tennel by the pollutant concentration, we used traffic volume and CO emission data by the automobile speed and CO concentration in the tunnel. And, when we estimated the traffic ventilation volume by natural and traffic ventilation force, we used traffic volume, automobile speed, tunnel area, automobile area data and so on. As the result of simple regression between predicted ventilation volume and traffic ventilation volume, we attained the regression coefficient 0.88, and achieved the relation form that predicted ventilation volume equal 0.12x traffic ventilation volume-92, 000. Using this equation, we estimated the ventilation volume to satisfy the enviromnental standards of several space, and calculated the required volume for mechanical ventilation. Incase of Kumhwa Tunnel, there is a need of mechanical ventilation all day long to satisfy air quality standard 9 ppm for 8 hours average and 10 ppm for the indoor air quality standard of public facilities.

• Advances in environmental research
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• v.1 no.1
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• pp.69-82
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• 2012

Based on the measurement data of the particulate matter with an aerodynamic diameter of less than or equal to a nominal 10 ${\mu}m$ (PM10) by the ${\beta}$-ray absorption method (BAM) equipped with an inlet heater and the gravimetric method (GMM) at two coastal sites in Korea, the optimal inlet heater temperature was estimated. By using a gas/particle equilibrium model, Simulating Composition of Atmospheric Particles at Equilibrium 2 (SCAPE2), water content in aerosols was estimated with varying temperature to find the optimal temperature increase to make the PM10 concentration by BAM comparable to that by GMM. It was estimated that the heated air temperature inside the BAM should be increased up to $35{\sim}45^{\circ}C$ at both sites. At this temperature range, evaporation of volatile aerosol components was minor. Similar ($30{\sim}50^{\circ}C$) temperature range was also obtained from the calculation based on the absolute humidity which changed with ambient absolute humidity and chemical composition of hygroscopic species.

• Transactions of the Korean Society of Mechanical Engineers
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• v.1 no.4
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• pp.171-181
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• 1977

This paper is aiming at calculating NOx concentration, which is one of the harmhul components of emission from the gasoline engine, formed in the combustor through the presess of combustion. Instantaneous temperature and concentration of each components for each division can be determined by the solution of simulatneous equation of reaction equation and equation of energy conservation, inputting the estimated temperature with a considerably wide rage of temperature. After determining instantaneous temperature and instantanous concentration of each components, the nonequilibrium calculation is performed based on the reaction kinetics in order to determine NOx concentration. To summarize the result abtained from the above method ;through the passage of NO concentration, NO concentration is the highest in the first division and it is gradually decreasing through the following divisions In the final division, NO concentation is the lowest.

• Journal of the Korea Furniture Society
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• v.25 no.3
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• pp.182-187
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• 2014

Underground shopping center has become a important commercial facility due to their good accessibility to the public transport. However, underground shopping center has high risk of air contaminants emission like formaldehyde and lowered indoor air quality. In this study, formaldehyde concentration of the underground shopping center was estimated according to the renovation and characteristics of space. It was found that newly renovated underground shopping center has low formaldehyde concentration. In case of closed entrance type, the formaldehyde concentration was 320 % higher than open type. Formaldehyde concentration was varied by product type and especially, high formaldehyde concentration was measured near the stores selling nail polish and cosmetics. It is important to apply appropriate ventilation system according to characteristics of space.

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1392-1396
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• 2004

The micellization of dodecylpyridinum chloride (DPC) assembled on aqueous gold nanoparticles has been studied as a function of concentration using Surface-Enhanced Raman Scattering (SERS). At the low concentration, the strong SERS band of the benzene ring moiety was observed at 1025 $cm^{-1}$, and assigned to “trigonal ring breathing”. According to high concentration of DPC, a new strong band was also appeared at 1012 $cm^{-1}$, which was assigned to “totally symmetry ring breathing”. The difference of two spectra seems to ascribe to the geometry of polar head group, i.e., pyridinium cation. These geometry exist flat-down at low concentration, whereas standing-up or tilted geometry at high concentration. The critical micelle concentration (CMC) was first obtained from the ratio of intensities of the two bands related to the benzene ring moiety by vibrational spectroscopy, and was about 28 mM. After the CMC, the benzene ring moiety in the micelle state was more restricted than in monomer state because there is no more change of intensities at 1012 $cm^{-1}$. In addition, the size of gold-assembled micelle was estimated using light scattering and it was about 328.3 nm.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.32-40
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• 2021

Vapor-driven solutal Marangoni flow is governed by the concentration distribution of solutes on a liquid-gas interface. Typically, the flow structure is investigated by particle image velocimetry (PIV). However, to develop a theoretical model or to explain the working mechanism, the concentration distribution of solutes at the interface should be known. However, it is difficult to achieve the concentration profile theoretically and experimentally. In this paper, to find the concentration distribution of solutes around 2D droplet, the reverse tracking method with an artificial neural network based on PIV data was performed. Using the method, the concentration distribution of solutes around a 2D droplet was estimated for actual flow data from PIV experiment.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.125-129
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• 2004

This study investigates the fatigue lift estimation of butt weld specimen for the railway vehicle by examining butt weld bead profiles. The butt weld beads, which are welded by semi-robot method, have non-uniform bead profiles described by $\theta$, p and h. The stress concentration factors, K$\_$t/, are changed by different $\theta$, p and h from 1.395 to 2.863. Hence, the sensitivity of K$\_$k/ is changed by each $\theta$, p and h. As $\theta$ becomes lower and p and h become higher, K$\_$t/ increases. The fatigue life can be estimated very closely for the AAY specimens without residual stress using only butt weld bead profiles. But, for the AAN specimens with residual stress, the fatigue life must be estimated by considering both the weld bead profiles and the residual stress data.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.88-94
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• 2000

The adsorption characteristics of Tharonil on granular activated carbon were experimentally investigated in an adsorber and in a packed column. It was estabilished that the adsorption equilibrium of Tharonil on granular activated carbon was more successfully fitted by Freundlich isotherm equation than Langmuir isotherm equation in the concentration range from 1 to 1000 mg/1. Intraparticle diffusivities (pore and surface diffusivity) of Tharonil were estimated by the concentration-time curve and adsorption isotherm. The estimated values of pore diffusivity and surface diffusivity are $6.70{\times}10^{-6}$ and $2.0{\times}10^{-9}cm^2/s$, respectively. From comparison of intraparticle diffusivities, it was found that surface diffusion was the limiting step for adsorption rate. The break time and breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.768-772
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• 2006

To assess the dietary exposure to 3-monochloropropane-1,2-diol (3-MCPD) from soy sauces, the levels of 3-MCPD in commercial soy sauces were analyzed with gas chromatography/mass spectrometry. Sixty nine out of the 72 soy sauces tested contained a level of 3-MCPD below $0.3\;{\mu}g/g$, the maximum limit in Korea. The average concentration of the 72 samples was $0.080\;{\mu}g/g$ and the highest concentration was $3.131\;{\mu}g/g$. On the basis of the consumption data, 3-MCPD concentration and body weight, the estimated daily exposures to 3-MCPD were ranged from 0.037 to $0.146\;{\mu}g/kg$ body weight (bw)/day for 95th percentile exposed population groups. Our estimated daily exposures are significantly lower than the provisional maximum tolerable daily intake (PMTDI) of $2\;{\mu}g/kg$ bw/day, which was established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA).

• Asian Journal of Atmospheric Environment
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• v.6 no.2
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• pp.111-117
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• 2012

To establish area specific control strategy for ambient ozone in the Seoul Metropolitan Area (SMA), the maximum ozone concentration in each local government district in the SMA were estimated by using the OZone Isopleth Plotting Package for Research (OZIPR) model. The modeling period was June 2000 and the emission inventory data used were from National Institute of Environmental Research (NIER). Except the islands of Incheon, whole Seoul and Incheon areas were volatile organic compounds (VOCs) limited, i.e., decreasing the oxides of nitrogen ($NO_X$) emission alone may increase the maximum ozone concentration upto certain point. In Gyeonggi, 12 areas were VOCs limited while 12 areas were in between VOCs limited and $NO_X$ limited, i.e., decreasing both $NO_X$ and VOCs emission may decrease the maximum ozone concentration. Majority of the estimated ozone values were lower than the measured values. The reason could be inaccuracy in emission inventories and/or transport from other areas. The same calculation was carried out for June 2004 and it was found that Seoul was still in the VOCs limited condition.