• Journal of Environmental Health Sciences
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• 제44권3호
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• pp.238-243
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• 2018

Objectives: The purpose of this study was to determine skin adhesion rate of children's modeling clay for exposure assessment. Methods: Children's modeling clays were classified into 10 categories as PVA clay, PVA soft clay, starch-based clay, foam clay, rubber clay, oil clay, muddy clay, terra clay, paper clay and slime. A total of 26 children's clay goods was selected. Moisture content (%) and hardness of clays were measured. Five adults aged 20 to 25were recruited for experiment. Gravimetric difference of modeling clay was determined after 3 minutes playing time. Skin adhesion rate ($g/min/cm^2$) was estimated bythe amount of skin adhesion per minute (g/min) and each individual's palm surface area ($cm^2$). Results: Twenty four of the 26 children's modeling clay products were adhesive to skins. Two products of foam and rubber clay were not adhered to skin. For the 24 products, the average skin adhesion rate was $5.5{\times}10^{-4}{\pm}4.0{\times}10^{-4}g/min/cm^2$. The highest skin adhesion rate was $1.3{\times}10^{-3}{\pm}4.4{\times}10^{-4}g/min/cm^2$ for paper clay. The lowest skin adhesion rate was $4.6{\times}10^{-5}{\pm}1.1{\times}10^{-4}g/min/cm^2$ for oil clay. The skin adhesion rate was increased with increase of moisture content. Adhesion rates of some clays were varied by person and testing trials. Conclusion: The study determined skin adhesion rate of children's modeling clay. The adhesion rate is useful for exposure and risk assessments and setting safety guideline to protect children's health.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권1호
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• pp.760-767
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• 2020

Sustainable growth of hydroelectric power plants is expected in consideration of climate change and energy security. However, hydroelectric power plants always have a risk of water hammer damage, and safety assurance is very important. The water hammer phenomenon commonly occurs during operations such as rapid opening and closing of the valves and pump/turbine shutdown in pipe systems, which is more common in cases of emergency shutdown. In this study, a computational numerical model was developed using the MOC-FDM scheme to reflect the mechanism of water hammer occurrence. The proposed model was implemented in boundary conditions such as reservoir, pipeline, valve, and pump/turbine conditions and then applied to simulate hypothetical case studies. The analysis results of the model were verified using the analysis results at the main points of the pipe systems. The model produced reasonably good performance and was validated by comparison with the results of the SIMSEN package model. The model could be used as an efficient tool for the safety assessment of hydroelectric power plants based on accurate prediction of transient behavior in the operation of hydropower facilities.

• Korean Journal of Food Science and Technology
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• 제42권5호
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• pp.541-548
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• 2010

In this study, contamination levels of 7 N-nitrosamine were investigated in processed meat products (n=51), processed fish products (n=62), salted fish pickles (n=20), and beer and malt beverages (n=21) using a GC/PCI-MS/MS method. The limits of detection (LOD) of the N-nitrosamines ranged from 0.2 to 0.5 ${\mu}g$/kg. In addition, methods were used to estimate the recovery of 7 N-nitrosamines, which ranged from 84 to 112%. N-nitrosamines were detected in 89 (58%) out of 154 samples. The exposure of an entire population group to N-nitrosamines through food intake was estimated using the average body weight of the total population and average daily food consumption, to perform risk assessment based on reports of a national health and nutrition survey. The results indicated that the daily intake of N-nitrosamines over a life time was $4.92{\times}10^{-7}$ mg/kg b.w./day. The margin of exposure (MOE) for the general population, estimated using the benchmark dose lower confidence limit 10 ($BMDL_{10}$) of N-nitrosodimethylamine, was 208,939, which was found to be safe.

• Korean Journal of Food Science and Technology
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• 제37권5호
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• pp.850-855
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• 2005

Model was developed to predict the growth of Listeria monocytogenes in raw pork. Experiment condition for model development was full 5-by-7 factorial arrangements of temperature (0, 5, 10, 15, and $20^{\circ}C$) and time (0, 1, 2, 3, 18, 48, and 120 hr). Gompertz values A, C, B, and M, and growth kinetics, exponential growth rate (EGR), generation time (GT), lag phase duration (LPD), and maximum population density (MPD) were calculated based on growth increased data. GT and LPD values gradually decreased, whereas EGR value gradually increased with increasing temperature. Response surface analysis (RSA) was carried out using Gompertz B and M values, to formulate equation with temperature being main control factor. This equation was applied to Gompertz equation. Experimental and predictive values for GT, LPD, and EGR, compared using the model, showed no significant differences (p<0.01). Proposed model could be used to predict growth of microorganisms for exposure assessment of MRA, thereby allowing more informed decision-making on potential regulatory actions of microorganisms in raw pork.

• Journal of The Korean Society of Integrative Medicine
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• 제9권3호
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• pp.37-45
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• 2021

Purpose : This study aimed to present normative data and cut-off points for older Korean adults completing the Montreal Cognitive Assessment - Korean (MoCA-K), which is used as a screening test for mild cognitive impairment in Korea. Methods : A total of 195 healthy adults ≥60 years were recruited. All participants completed the MoCA-K and the Korean - Mini-Mental State Examination (MMSE-K) to assess their cognitive function. Participants were divided into six groups based on their age: 60-64 years, 65~69 years, 70~74 years, 75~79 years, 80~84 years, and 85~89 years. Results : The results revealed that MoCA-K score decreased significantly with age (mean score ± standard deviation [SD]; 27.63±2.80 in subjects aged 60~64 years; 27.00±2.39 in subjects aged 65~69 years; 24.94±2.96 in subjects aged 70~74 years; 24.74±3.37 in subjects aged 75~79 years; 22.59±4.72 in subjects aged 80~84 years; and 18.83±5.38 in subjects aged 85~89 years; p<.001). Additionally, MoCA-K score also increased significantly with educational level (mean score±standard deviation [SD]; 19.95±4.78 in no formal education group; 24.95±2.22 in elementary school graduated group; 26.35±2.72 in middle school graduated group; 28.32±1.36 in high school graduated group; and 28.50±1.51 in more than college graduated group; p<.001). The optimal cut-off points were 24/25 for 60~69 years old group, 21/22 for 70~79 years old group, 17/18 for 80~84 years old group, and 13/14 for 85~89 years old group. The optimal cut-off points were 15/16 for individuals who were illiterate, 22/23 for individuals with 6 years of education, 22/24 for individuals with 9 years of education, and 26/27 for individuals with 12 or more years of education. Conclusions : This study presents normative data and cut-off points for the MoCA-K in older Korean adults. This data will facilitate more accurate detection and follow-up of the risk of mild cognitive impairment in this population, taking into consideration age and education. Future studies are required that should focus on the cut-off score on the level of education according to age.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• 제28권1호
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• pp.15-21
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• 2022

The purpose of our study was to investigate the migration level of lead (Pb), cadmium (Cd), and barium (Ba) from glassware into a food simulant and to evaluate the exposure of each element. The test articles were glassware, including tableware, pots, and other containers. Pb, Cd, and Ba were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analytical performance of the method was validated in terms of its linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. The monitoring was performed for 110 samples such as glass cups, containers, pots, and bottles. a food simulant. Migration test was conducted at 25? for 24 hours in a dark place using 4% acetic acid as a food simulant. Based on the data; exposure assessment was carried out to compare the estimated daily intake (EDI) to the human safety criteria. The risk levels of Pb and Ba determined in this study were approximately 1.9% and 0.3% of the provisional tolerable weekly intake (PTWI) and tolerable daily intake (TDI) value, respectively, thereby indicating a low exposure to the population.

• Journal of Korean Society for Geospatial Information Science
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• 제24권1호
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• pp.43-50
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• 2016

Urbanization in Korea has increased significantly and subsequently, various facilities have been concentrated in urban areas at high speed in accordance with a growing urban population. Accordingly, damages have occurred due to a variety of disasters. In particular, fire damage among the social disasters caused the most severe damage in urban areas along with traffic accidents. 44,432 cases of fire occurred in 2015 in Korea. Due to these accidents, 253 were killed and property damage of 4,50 billion won was generated. However, despite the efforts to reduce a variety of damage, fire danger still remains high. In this regard, this study collected fire data, generated from 2007 to 2014 through the Jinju Fire Department and the National Fire Data System(NFDS) and calculated fire risk by analyzing the clustering of fire cases and facilities in Jinju-si based on the current DB of facilities, offered by the Ministry of Government Administration and Home Affairs. As a result, the risk ratings of fire occurrence were classified as four stages under the standards of the US Society of Fire Protection Engineers(SEPE). Business facilities, entertainment facilities, and automobile facilities were classified as the highest A grade, detached houses, Apartment houses, education facilities, sales facilities, accommodation, set of facilities, medical facilities, industrial facilities, and life service facilities were classified as U grade, and other facilities were classified as EU grade. Finally, hazardous production facilities were classified as BEU grade, the lowest grade. In addition, in the case of setting the standard with loss of life, the highest risk facility was the hazardous production facilities, while in the case of setting the standard with property damage, a set of facilities and industrial facilities showed the highest risk. In this regard, this study is expected to be effectively utilized to establish the fire reduction measures against facilities, distributed in urban space by calculating risk grades regarding the generation frequency, casualties, and property damage, through the classification of fire, occurred in the city, according to the facilities.

• Journal of the Society of Disaster Information
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• 제16권4호
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• pp.701-711
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• 2020

Purpose: In this study, the risk of flammability of a liquid mixture was experimentally confirmed because the purpose of this study was to confirm the increase or decrease of the flammability risk in a mixture of two substances (combustible+combustible) and to present the risk of the mixture. Method: Flash point test method and result processing were tested based on KS M 2010-2008, a tag sealing test method used as a flash point test method for crude oil and petroleum products. The manufacturer of the equipment used in this experiment was Japan's TANAKA. The flash point was measured with a test equipment that satisfies the test standards of KS M 2010 with equipment produced by the company, and LP gas was used as the ignition source and water as the cooling water. In addition, when measuring the flash point, the temperature of the cooling water was tested using cooling water of about 2℃. Results: First of all, in the case of flammable + combustible mixtures, there was little change in flash point if the flash point difference between the two substances was not large, and if the flash point difference between the two substances was low, the flash point tended to increase as the number of substances with high flash point increased. However, in the case of toluene and methanol, the flash point of the mixture was lower than that of the material with a lower flash point. Also, in the case of a paint thinner, it was not easy to predict the flash point of the material because it was composed of a mixture, but as a result of experimental measurement, it was measured between -24℃ and 7℃. Conclusion: The results of this study are to determine the risk of mixtures through experimental studies on flammable mixtures for the purpose of securing the effectiveness of the details of the criteria for determining dangerous goods in the existing dangerous goods safety management method and securing the reliability and reproducibility of the determination of dangerous goods Criteria have been presented, and reference data on experimental criteria for flammable liquids that are regulated in firefighting sites can be provided. In addition, if this study accumulates know-how on differences in test methods, it is expected that it can be used as a basis for research on risk assessment of dangerous goods and as a basis for research on dangerous goods determination.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제20권4호
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• pp.282-294
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• 2010

The purpose of SAICM (Strategic Approach to International Chemicals Management) is to minimize the health and environmental hazards from the production and the consumption of chemicals by improving the chemicals management capability of developing countries and implementing a system of the risk assessment and the management based on the precautionary principle until 2020. To achieve this purpose, the UN has prescribed the principles, objectives and establishment of an action plan for the chemicals management strategy which must be carried out at international, local, and national levels, and requested the implementation of the Global Plan of Action (GPA) comprising of 273 recommendations in 36 work areas. SAICM is currently based on voluntary participation, but is expected to become the basic framework of international order in relation to chemicals management in the future. This study aims to analyze the practice in the occupational safety and health area relating to implement 273 recommendations of the GPA, and propose complementary measures for the system in order to provide political advices for establishing future plans to manage industrial chemicals. Twenty three areas of total 36 work areas and 161 items of 273 recommendations have relevance to occupational safety and health areas. We have found that, as a national implementation level, 157 of 161 industrial safety and health items are being implemented at a satisfactory level in regard to the implementation of the GPA, while 4 items, including the ratification of the ILO Conventions 170, 174, 184, and support for GHS (Globally Harmonized System of Classification and Labeling of chemicals) implementation of developing countries, require additional complementary measures for the system and operation.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제13권3호
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• pp.373-384
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• 2000

To assess the safety of nonlinear steel frame structures subjected to short duration dynamic loadings, especially seismic loading, a nonlinear time domain reliability analysis procedure is proposed in the context of the stochastic finite element concept. In the proposed algorithm, the finite element formulation is combined with concepts of the response surface method, the first order reliability method, and the iterative linear interpolation scheme. This leads to the stochastic finite element concept. Actual earthquake loading time-histories are used to excite structures, enabling a realistic representation of the loading conditions. The assumed stress-based finite element formulation is used to increase its efficiency. The algorithm also has the potential to evaluate the risk associated with any linear or nonlinear structure that can be represented by a finite element algorithm subjected to seismic loading or any short duration dynamic loading. The algorithm is explained with help of an example and verified using the Monte Carlo simulation technique.