• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권12호
• /
• pp.602-607
• /
• 2003

We show three-dimensional distribution of voltages resulted from the leakage current originated from outdoor electrical facilities in a submerged area. In case these facilities are grounded by the neutral line multiple grounding method, the existence of ungrounded electrical facilities can cause a disastrous effect on near-by passengers. In order to investigate this situation, we installed a real-scale test field for the experiment type I (for the leakage current path between a enclosure grounded electrical facility and another enclosure grounded one), and that for the experiment type II (for the leakage current path between a enclosure grounded electrical facility and another ungrounded one). For both cases, we carried out three-dimensional monitoring of the voltage distribution while varying additional conditions such as the exposure of the underground cables and the finishing of cable connection part. The result shows that a disastrous effect on human safety can arise from the leakage current without a pertinent measure for the construction and maintenance of outdoor electrical facilities.

• International Journal of Concrete Structures and Materials
• /
• 제11권1호
• /
• pp.69-84
• /
• 2017

This paper presents results of an experimental investigation on the behaviour of bond between external glass fibre reinforced polymer reinforcement and concrete exposed to three different environmental conditions, namely, temperature cycles, wet-dry cycles and outdoor environment separately for extended durations. Single shear tests (pull-out test) were conducted to investigate bond strengths (pull-out strengths) of control (unexposed) and exposed specimens. Effect of the exposure conditions on the compressive strength of concrete were also investigated separately to understand the effect of changing concrete compressive strength on the pull-out strength. Based on the comparison of experimental results of exposed specimens to control specimens in terms of bond strengths, failure modes and strain profiles, the most significant degradation of pull-out strength was observed in specimens exposed to outdoor environment, whereas temperature cycles did not cause any deterioration of strength.

• 환경위생공학
• /
• 제11권3호
• /
• pp.47-52
• /
• 1996

Personal exposure levels of $NO_{2}$ for office workers and housewives Living in A-San and neighboring prefectures were measured in two seasons with $NO_{2}$ filter badge. $NO_{2}$ concentrations in indoor and outdoor air in their offices and houses were also measured in the same periods. Personal exposure levels in winter ranged from 13 to 132 ppb and its distribution pattern was remarkably different from the other seasons (15.2-17.9 ppb). This fact suggests that use of heating apparatus affects largely $NO_{2}$ indoor air pollution in winter seasons. Actually, $NO_{2}$ exposure levels of subjects used Kerosene heater (43.6ppb) and gas heater (33.4ppb) were higher than those of subjects unused heating apparatus (18.0ppb). Personal exposure levels of $NO_{2}$ for man and woman Living in the same houses were correlated well each other. The time spent indoors for office workers and housewives were both longer than 22 hour a day. Home staying time was about 60% of total indoor staying time for office workers and 90% or more for housewives. Personal exposure levels were significantly related to indoor exposure levels at home all seasons. Furthermore, personal exposure levels could be estimated from $NO_{2}$ concentrations and staying times in various Living environment.

• 한국산업보건학회지
• /
• 제32권4호
• /
• pp.402-413
• /
• 2022

Objectives: In this study, the scale of exceeding the extreme heat exposure standard at the construction site was estimated using the nationally approved statistical data and wet bulb globe temperature modeling method. By comparing and analyzing the modeling results with the existing work environment monitoring results, the risk of heat exposure at outdoor construction sites was considered. Methods: Using the coordinates of second level administrative districts and meteorological observatories as the key, the automated synoptic observing system data and building permit data for 2021 were matched. The wet-bulb temperature was obtained using Stull's formula, and the globe temperature was obtained using the Tg_KMA2006 model. WBGT was calculated using these. Excess rates were obtained compared to exposure limits for heavy work-continuous work and moderate work-25% rest. It was compared with the results of the work environment monitoring in 2020. Results: As a result, 1,827,536 cases were estimated for 11,052 workplaces in one year. This is much higher than the 5,116 cases of 3818 workplaces of the existing work environment monitoring results. It is confirmed that the exposure limit was exceeded in 10.6~24.0% of the entire period and 70.2~84.1% of the peak period of the heat wave. It is very high compared to 0.9% of the existing work environment monitoring result. Conclusions: It is necessary to improve the system of monitoring and statistics related to extreme heat. Additional considerations are needed regarding WBGT estimation methods, meteorological data, and evaluation time. Various follow-up risk assessment studies for other industries and time series need to be continued.

• Asian Journal of Atmospheric Environment
• /
• 제12권3호
• /
• pp.204-214
• /
• 2018

Indoor air quality was investigated in homes and daycares located in areas with heavy traffic in Seoul, South Korea from November 2013 to January 2014. Indoor and outdoor air quality measurements were collected for 48 hours in four children's homes and daycare centers. The I/O ratio (Indoor to outdoor ratio) for each major air pollutant ($NO_2$, black carbon, $PM_{10}$, and $PM_{2.5}$) was calculated, and $NO_2$ and $PM_{10}$ concentration profiles were analyzed based on indoor activity diaries recorded during the 48 hours. Most I/O ratios for $NO_2$, black carbon, $PM_{10}$, and $PM_{2.5}$ at daycare centers were less than one. At homes, I/O ratios for black carbon, $PM_{10}$, and $PM_{2.5}$ were less than one; however, most I/O ratios for $NO_2$ were greater than one due to the usage of gas stoves. The children's exposure to indoor air pollutants was calculated using a time-weighted average exposure method, and the daily intake level for each pollutant was determined.

• Corrosion Science and Technology
• /
• 제12권5호
• /
• pp.209-214
• /
• 2013

In the industry, accelerated corrosion test is used for the life time prediction. When anti-corrosion test proceeds in real environments, it is difficult that we predict and evaluate the corrosion life time because of the long test time such as 10 years or more time. Accelerated corrosion test and Salt spray test are able to test corrosion life time of products in the laboratory instead of outdoor corrosion test. Experimental procedure is selected for the corrosion standard specimen, exposure of the specimens, measurements of the mass loss and evaluating the mass loss data. As a result, the acceleration factor of the accelerated corrosion test to the outdoor corrosion test is 414.8. Therefore we can predict the corrosion life time of carbon steel during a short time period.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2008년도 춘계학술대회 논문집
• /
• pp.596-598
• /
• 2008

• 한국환경과학회지
• /
• 제22권2호
• /
• pp.163-171
• /
• 2013

The aggregate risk assessment on xylene and ethylbenzene was carried out according to the guidance established newly in 2010 with the purpose of providing information for risk management. In human exposure assessment, the results indicated that lower ages were exposed more and that, in the interior space at home, the highest level of human exposure occurred via inhalation. At outdoor spaces, exposures via inhalation and drinking were less than 1%. In human health risk characterization, xylene showed HI(Hazard Index) < 1 in all ages. When reasonable maximum exposure(RME) was applied, HI for young children was 0.64. The HI of ethylbenzene was also below 1(0.02~0.04) in all ages, indicating no potential risk. From this study, it is considered that xylene need to be continous monitoring with interest because this substance may be more sensitive on young age group. In additon, to reduce the uncertainty of the risk assessment, the korean exposure factors on young age group such as infant, children had to be established as soon as possible.

• 환경위생공학
• /
• 제17권2호
• /
• pp.26-33
• /
• 2002

Ultimate objective of industrial hygiene is the prevention of health impairment that may result from exposure to chemicals at workplace. Workers in solvent thinner-using occupation environment may be highly exposed to VOCs (volatile organic compounds) because solvent thinner has been used extensively such as painting, spraying, degreasing, coating and so on in Korea. The purpose of this study was to recognize, evaluate, and propose the control methods of VOCs from solvent thinner-using workplace. Five target volatile organic compounds (benzene, toluene, ethylbenzene, o-xylene, and m-xylene) were monitored in H company of Shiwa Industrial Complex and analyzed in perosnal, occupational indoor and outdoor during working hours simultaneously. Engineering control such as local ventilation should be made in considering the long-term exposure, though measured VOCs concentration did not exceed the workplace exposure standards. In addition, air cleaning device should be installed in local ventilation because Shiwa Industrial Complex has had the serious ambient air pollution. Currently, environmental purification using $TiO_2$ photocatalyst have attracted a great deal of attention with increasing number of recent environmental problems. In this study, $TiO_2$ sol coated on the ceramic bead was prepared by sol-gel method and the photodegradation of target compounds was investigated in gas phase by the exposure to UV-A lamp(365nm) in a batch system.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2005년도 국제학술대회
• /
• pp.373-377
• /
• 2005

The work of hairdressers includes washing, coloring, bleaching, permanent waving, conditioning, and cutting hair. Hairdressers are subjected to a number of physical and toxicological hazards. The toxicological hazards are those resulting from exposure to a wide range of chemicals and from chemicals are usually classified active processes. In this study, twenty beauty shops were selected to assess the exposure to indoor air pollutants such as VOCS and particulate matter($PM_{10}$) during one month from September 1 to September 30, 2003. Indoor air quality of beauty shops might be worse by vehicle emissions because the beauty shops were generally located near roadways. Personal exposures to VOCs and PM lo were related to indoor concentrations of beauty shops. According to the questionnaire, hairdressers complained of sore throat, eye irritation, and nervousness as physical symptoms. Conclusively, customers as well as workers in the beauty shops might be highly exposed to air pollutants from indoor sources and outdoor sources. Therefore, proper management methods should be taken to improve the indoor air quality in beauty shops.