• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.313-323
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• 2017

Objectives: This study aimed to assess exposure to black carbon(BC) among forklift operators and to identify environmental and occupational factors influencing their BC exposure. Methods: We studied a total of 23 forklift operators from six workplaces manufacturing paper boxes. A daily BC exposure assessment was conducted during working hours from January to April 2017. A micro-aethalometer was used to monitor daily BC exposure, and information on work activities was also obtained through a time-activity diary(TAD) and interviews. BC exposure records were classified into four categories influencing BC exposure level: working environment, workplace, forklift operation, and job characteristics. Analysis of variance(ANOVA) was used to compare average BC exposure levels among the four categories and the relationships between potential factors and BC exposure were analyzed using a multiple linear regression model. Results: The operators' daily exposure was $12.9{\mu}g/m^3$(N=9,148, $GM=7.5{\mu}g/m^3$) with a range: $0.001-811.4{\mu}g/m^3$. The operators were exposed to significantly higher levels when they operate a forklift in a room ${\leq}20,000m^3$($AM=12.3{\mu}g/m^3$), in indoor workplaces($AM=16.3{\mu}g/m^3$), when they operate a forklift manufactured before 2006 ($AM=13.2{\mu}g/m^3$), a forklift with a loading limit of four-tons($AM=27.1{\mu}g/m^3$), with a roll and bale type clamp($AM=17.1{\mu}g/m^3$), and with no particulate filter($AM=15.7{\mu}g/m^3$). Conclusions: Occupational factors including temperature, smoking, season, daytime, room volume($m^3$), location of operating, and manufacturing era and model of forklift influenced the BC exposure of forklift operators. The results of this study can be used to minimize the BC exposure of forklift operators.

• Korea journal of population studies
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• v.21 no.2
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• pp.113-143
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• 1998

Married women who follow occupations have remarkably increased. Economic-activies married women[EAMW] have experienced a great degree of role confilcts as the results of that they should play the role of wage workers and do duty as household affairs as well as raise children. To understand problems of EAMW and to make alterniative plans for EAMW, the daily life actives of EAMW should be examined. This study attempts to understand the daily life activites of EAMW. To obtain the goal this research generalizes the daily life actives of EAMW. classifies the patterns the activites, and analyzes the activites in the micro-level. The acivites of EAMW mainly consist of formal business and household affairs. The spatial bounds of activities are influenced by weekdays and holidays. During the weekday their activities are mainly found around residences and/or work places; while, during the weekend, they are discovered around residences and/or around residences or relatives who take care of their children. EAMW move longer distance rather than a full-time housewife; however, the activites of EAMW are residential orientation like those of full-time housewives. The role conflicts of EAMW are mainly from social cultural structure, the distance between workplace and residence, and the location of public service institutes.

• Clean Technology
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• v.20 no.2
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• pp.171-178
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• 2014

In this study we have examined the health risk factors and analyzing data of laborers working at the welding operation at large-sized casting process. In order to improve the working environment of workplace, an effective ventilation method was proposed after performing CFD (computational fluid dynamics) modeling and measurement of pollutants. As a result of examining the health risk factors of workers, oxidized steel dust is the main pollution source in the company A, welding fume in the companies B and C, and welding fume and oxidized steel dust in the company D. The fume concentration in the workers' breathing zone was $0.05{\sim}4.37mg/m^3$, and the fume concentration in the indoor air at the welding process was $0.13{\sim}7.54mg/m^3$. From a result of CFD, a local exhaust with an exhaust duct adjacent to welding point was found to be most effective in case of the exhaust process. In case of air supply, we found that a desired location of air supply fan would be at the end of the opening. If a standardizing the ventilation system for tunnel-type semi-enclosed space at a large-sized casting process is introduced in welding work places in the future, it would be more effective to protect the health of welding workers working at the casting industry and shipbuilding industry and improve the work environment.

• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.1-8
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• 2021

Among the flare systems that handle discharged substances from safety valves, the knockout drum was a key facility for safety, but the installation standards were not clear, so it was necessary to review the standards acceptable to the workplace and regulatory agencies. After investigating the domestic and foreign technical standards of knockout drums and the deficiencies of previous studies, research was first conducted on the degree of mass discharge, the installation location of the intermediate knockout drum, and the effect of changes in the composition of the discharged material. As a result of the study under the process simulation conditions, the gas-liquid separation of the knockout drum was completed in a small amount of less than 7,500kg/hr. However, when more than that was released, the gas-liquid separation effect was small even with the addition of an intermediate knockout drum. In addition, when the composition ratio of the material easily condensed was increased (molar fraction 10%), the gas-liquid separation effect of the knockout drum increased in the case of mass release. The gas-liquid separation effect was analyzed to be greater when the knockout drum was installed adjacent to the stack than the knockout drum was installed adjacent to the process equipment.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.521-531
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• 2021

Vacuum Pressure Impregnation (VPI) is a process that enhances physical properties by coating some types of epoxy resins on windings of stator used in large rotators such as generators and motors. During vacuum and pressurization of the VPI process, resin gas is generated by vaporization of epoxy resin. When the tank is opened for curing after finishing impregnation, resin gas is leaked out of the tank. If the leaked resin gas spreads throughout the workplace, there are safety and environmental problems such as fire, explosion and respiratory problems. So, exhaust system for resin gas is required during the process. In this study, a case study of exhaust efficiency by location of vent was conducted using Computational Fluid Dynamics (CFD) in order to design a system for exhausting resin gas generated by the VPI process. The optimal exhaust system of this study allowed more than 90% of resin gas to be exhausted within 1,800 seconds and reduced the fraction of resin gas below the Low Explosive Limit (LEL).

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.11-18
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• 2024

If flammable liquid leaks, vapor evaporated from the pool can cause poisoning or suffocation to workers, leading to secondary accidents such as fires and explosions. To prevent such damage, ventilation facilities shall be installed when designing indoor workplaces. At this time, the behavior varies depending on the characteristics of the leaked chemical, so it is necessary to select a suitable vent location according to the material. Therefore, 3D CFD simulations were introduced to derive optimal vent position and ventilation efficiency was quantitatively evaluated by vent position. At this time, assuming a situation in which flammable liquids leak at indoor workplaces to form pools, the concentration of vapor evaporated from pools was compared to derive the optimal vent position. As a result of research on toluene with high vapor density, ventilation efficiency was confirmed to be the highest at the upper supply-lower exhaust, and it is judged that introducing it can achieve about 3.7 times ventilation effect at the same maintenance cost. Through this study, it is expected that the workplace will be able to secure workers' safety by applying simulation results and installing ventilation ports.