• Toxicological Research
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• v.35 no.2
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• pp.119-129
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• 2019

As the use of cosmetics has greatly increased in a daily life, safety issues with cosmetic ingredients have drawn an attention. Drometrizole [2-(2'-hydroxy-5'-methylphenyl)benzotriazole] is categorized as a sunscreen ingredient and is used in cosmetics and non-cosmetics as a UV light absorber. No significant toxicity has been observed in acute oral, inhalation, or dermal toxicity studies. In a 13-week oral toxicity study in beagle dogs, No observed adverse effect level (NOAEL) was determined as 31.75 mg/kg bw/day in males and 34.6 mg/kg bw/day in females, based on increased serum alanine aminotransferase activity. Although drometrizole was negative for skin sensitization in two Magnusson-Kligman maximization tests in guinea pigs, there were two case reports of consumers presenting with allergic contact dermatitis. Drometrizole showed no teratogenicity in reproductive and developmental toxicity studies in which rats and mice were treated for 6 to 15 days of the gestation period. Ames tests showed that drometrizole was not mutagenic. A long-term carcinogenicity study using mice and rats showed no significant carcinogenic effect. A nail product containing 0.03% drometrizole was nonirritating, non-sensitizing and non-photosensitizing in a test with 147 human subjects. For risk assessment, the NOAEL chosen was 31.75 mg/kg bw/day in a 13-week oral toxicity study. Systemic exposure dosages were 0.27228 mg/kg bw/day and 1.90598 mg/kg bw/day for 1% and 7% drometrizole in cosmetics, respectively. Risk characterization studies demonstrated that when cosmetic products contain 1.0% of drometrizole, the margin of safety was greater than 100. Based on the risk assessment data, the MFDS revised the regulatory concentration of drometrizole from 7% to 1% in 2015. Under current regulation, drometrizole is considered to be safe for use in cosmetics. If new toxicological data are obtained in the future, the risk assessment should be carried out to update the appropriate guidelines.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.371-392
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• 2010

Since the 21st century, to the worldwide computer, broadcasting, communications and other technologies have be developed. because of the Internet allows real-time information delivery, Information Society that was done quickly. In this study, using information technology, Active measures to enable e-commerce in agriculture is discussed. agricultural e-commerce to the consumer satisfaction surveys were conducted, too. In addition to, as a e-commerce features, informance, convenience, interface presented. After research results, I think information, convenience, interface is important to consumers. Consumers will be spent on activities having a new value. To respond to these consumers, Companies must evaluate the internal capabilities. and outside the assessment continuously. E-commerce will give an effective way to companies. And e-commerce will develop further in the future. Therefore, e-commerce will be done by the long-term plan.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.155-160
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• 2010

In this study, detailed assessment for durability performance were performed on the chloride protected concrete structures to investigate the effectiveness of chloride protection. And economical efficiency for the chloride protected concrete structures were studied by LCC(Life Cycle Cost) analysis. In the comparison result of the first section repair time, it was found that the chloride protected concrete structures was economical better than the non-protected concrete structures in the long term. According to the analysis result of the accumulated chloride concentration by used time and chloride ion concentration by depth, it can be seen that the permeation through time from chloride has increased two times in the chloride protected concrete structures.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.1-6
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• 2003

In this work, procedure evaluating failure modes such as pipe rupture, large scale leak, and small scale leak was suggested using equations to assess remaining strength by corrosion failure. Additionally, the method to predict probability of failure was suggested according to the aforementioned failure modes, and by combining data on corrosion rate, probability of long-term failure can be induced. This work will be very useful in predicting lifetime or exchanging period of pipeline.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.245-256
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• 2021

This study is significant in determining the reduction of safety accidents by applying PDCA's theory by subdividing it into a case analysis technique for construction sites by PDCA's theory. For this study, accidents accounted for the largest proportion of each type of disaster in the construction site were considered, and safety accidents were reduced through the PDCA theory through prior research. The analysis method of this study derived improvement plans by applying PDCA techniques to plan, implement, confirm, review, and improve disaster accidents at construction sites. The conclusions of this study are as follows. In the plan, first of all, measures shall be taken to prepare a safety management plan, to verify the implementation of the plan, and to verify the degree of implementation by the field manager. In the implementation, first of all, it is necessary to introduce a safety education history system to strengthen the safety education curriculum to suit the site, as long-term work is impossible for field workers depending on field conditions. First of all, it is necessary to strengthen the installation of safety facilities, including "work scaffolding" and "conducting prevention facilities" at construction sites. In management review and improvement, the risk assessment system for construction sites needs to be expanded first°.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.169-177
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• 2010

One of the most obvious climatic manifestations of urbanization in Korea is a trend towards higher air temperature. The trends of long-term annual temperature generally well describe the warming of urban areas. The increase of air temperature in urban area has been observed to the present since the meteorological observations in Korea began. The objective of this study is to explore the actual increase and the regional long-term trends of air temperature attributed to urbanization in the Korean Peninsula. Therefore, temperatures of the selected urban areas were compared with that of the surrounding rural areas, with the results varying by the application of the estimates of each region. The second objective is to separate the long-term trend of surface air temperature of global warming from urbanization and to find the actual temperature increase from urbanization in Korean peninsula. For the data analysis, daily air temperatures observed by the Korea Meteorological Administration (KMA) during between from 1961 and 2005 were used at five rural sites and cities. The re-analyzed surface air temperatures by the National Centers for Environmental Prediction (NCEP) was also carried out to compare the result from the observed air temperature in the Korean climate domain. In this study, the urban areas in Korea showed high increase rate of air temperature with $0.4^{\circ}C$ per decade during past 50 year period, while rural sites as Chupungryung with the $0.2^{\circ}C$ decadal increase rate. The analyses reflect that the urban area shows the high rate of temperature increase with $1.39^{\circ}C$ of regression value at the urban area, Seoul, and $0.43^{\circ}C$ at the rural site, Chupungnyeong during the period of 30 years. The temperature increas due to the urbanization only showed the increase range between $0.44^{\circ}C$ and $0.86^{\circ}C$, and the observed decrease in diurnal temperature range at five urban areas during the 30 years period.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.228-243
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• 2023

Bentonite is widely recognized and utilized as a buffer material in high-level radioactive waste repositories, mainly due to its favorable characteristics such as swelling capability and low permeability. Bentonite buffers play an important role in ensuring the safe disposal of radioactive waste by providing a low permeability barrier and effectively preventing the migration of radionuclides into the surrounding rock. However, the long-term performance of bentonite buffers still remains a subject of ongoing research, and one of the main concerns is the erosion of the buffer induced by swelling and groundwater flow. The erosion of the bentonite buffer can significantly impact repository safety by compromising the integrity of buffer and leading to the formation of colloids that may facilitate the transport of radionuclides through groundwater, consequently elevating the risk of radionuclide migration. Therefore, it is very important to numerically quantify the erosion of bentonite buffer to evaluate the long-term performance of bentonite buffer, which is crucial for the safety assessment of high-level radioactive waste disposal. In this technical note, Two-region model is introduced, a proposed model to simulate the erosion behavior of bentonite based on a dynamic bentonite diffusion model, and quantitative evaluation is conducted for the bentonite buffer erosion with this model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.385-392
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• 2014

The isolators have been generally used to reduce a seismic force. If the isolators apply to the nuclear power plants(NPPs), the durability and capacity for the structures and equipments should be ensured during the life time. In this study, the long-term behavior of isolated NPPs was analyzed for ensuring the seismic safety. The properties of isolator due to the age-related degradation were analyzed. And the seismic behavior of isolated buildings was analyzed by considering the aging of rubber bearings in different temperature environments. According to the analysis results, the natural frequency of structures was increased with time. But the maximum acceleration and maximum displacement of isolated structures have not changed significantly. Although the damaged of structure did not occurred by aging of isolators, it was presented that the spectral acceleration at the target frequency of isolated structure increased with the temperature. Therefore the isolators in the isolated buildings should be carefully designed and manufactured considering the temperature-dependancy of rubber material.

• Safety and Health at Work
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• v.2 no.1
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• pp.39-51
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• 2011

Objectives: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. Results: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxy-ethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.74-82
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• 1993

The present paper deals with the structural safety assessment techniques for independent type B spherical LNG tank against fatique crack initiation and propagation, which contains fellowing 3 steps. 1) Prediction of long term distribution of wave induced stresses and fatique crack intiation life using cumulative damage theory which were described at the 1st report. 2) Surface crack propagation analysis to verify that initial defects cannot penetrate tank plate. 3) Passing-through fatigue crack propagation analysis was performed based on LBF(Leak Before Failure ) theory.