• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.82-88
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• 2003

Four kinds of low calorie mayonnaises containing 1.2% of sodium alginate, 1.0% of guar gum, 1.0% and 1.2% of xanthan gum and one control mayonnaise containing 78.5% of oil without gums were manufactured in pilot scale. Fresh control mayonnaise was higher in viscosity and turbidity than low calorie mayonnaise with gums. During storage at -1$0^{\circ}C$, viscosity and turbidity of control mayonnaise decreased sharply, whereas those of low calorie mayonnaise with gums decreased slightly. Scanning electron microscopy showed that fresh mayonnaise was composed of heterogeneous population of dispersed spherical oil droplets (<10 ${\mu}{\textrm}{m}$), and oil droplet size of control mayonnaise was smaller than any other low calorie mayonnaise. During storage at -1$0^{\circ}C$, a shift in oil droplet size toward larger oil droplets was frequently observed in control mayonnaise as a result of coalescence of oil droplets. Oil separation and turbidimetric study also confirmed that coalescence of oil droplets was occurring during this accelerated aging treatments.

• Elastomers and Composites
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• v.47 no.3
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• pp.254-258
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• 2012

Material characteristics and the prediction of life time of polyacrylic rubber (ACM) for automotive engine gasket were studied. Two kinds of ACM rubber compounds, having chlorine cure-site and carboxyl cure-site, were made with optimum formulations and the properties of each materials were examined. As a test results for the thermal properties and compression set, which are very important in the application for the automotive engine gasket, the compound using ACM with carboxyl cure-site was evaluated as having a better characteristics than that of ACM with chlorine cure-site. Arrhenius relationship based on time-temperature superposition principle (TTSP) was obtained through the accelerated heat aging test to predict the useful life-time for the compound using ACM with carboxyl cure-site.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2054-2060
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• 2016

As the aging society is accelerated, the population with dementia grows significantly faster. Because there is no complete cure of dementia, it is of great importance to detect the disease at a very early stage and prevent its fast aggravation through evaluation of MCI(Mild Cognitive Impairment) which happens before dementia. The current assessment of MCI conducts only in the form of hand-written data and by 1:1 face to face communication between the subjects and the examiners. Due to this, both examiners' fatigue rate and evaluation error rate increase. Further, there are some limitations in utilizing and analyzing data collected. Against the problems, therefore, there is a need to develop a computerized system by which MCI is assessed, and the results are saved and analyzed. This paper presents the development of such a system enabling MCI evaluation, its related data collection and analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3633-3642
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• 2015

Single-base propellants contain a single energetic component: nitrocellulose. Accurate predictions of propellant shelf-life should result in cost savings in terms of human and material resources. This study derived an optimized kinetic model reaction order that described stabilizer consumption and estimated propellant shelf-life. High temperature accelerated aging tests gave an optimum reaction order value of 1.15481, from which the minimum standard error of a linear regression estimate of 16.284 was obtained. At normal storage temperature of $21-30^{\circ}C$, propellants should have a safe shelf-life of 140 years, and a minimum of 35 years. It is necessary to consider the temperature range in ammunition storage areas to predict propellant shelf-life more accurately.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.207-210
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• 2017

The suspension arrangement of insulators provides flexibility and assists in power transmission in transmission lines. The performance of the insulator string is strongly influenced by the environmental conditions to which it is exposed, its shape and the inherent material properties of suspension-type insulators. The suspension-type insulators are mostly made from glass, porcelain and ceramic material due to their high resistivity. Irregularity in charge distribution throughout the porcelain insulator may lead to accelerated aging and electrical breakdown. A very high and steep lightning impulse voltage may also cause breakdown of suspension-type insulators. We investigated various material characteristics such as alumina addition, surface morphology, x-ray diffraction pattern and relative density of suspension porcelain insulators manufactured in 1989 (36,000 lbs.), 1995 (36,000 lbs.) and 2001 (36,000 lbs.) by the KRI Company for use in 154 kV high power transmission lines. We compared the material characteristics of these porcelain insulators with that of the top-of-the-line porcelain insulators (36,000 lbs.) manufactured by the NGK Company in 2000. These suspension-type porcelain insulators were exposed to arc and flashover tests to examine their electrical and mechanical strength. It was noted that alumina addition (17 wt.%) for K-2001 was one of the major contributors to the enhancement of the performance of the porcelain insulators and to their ability to withstand very high current generation during the arc test. The porcelain insulators manufactured during 2001 also showed the highest relative density of 95.8% as compared to the other insulators manufactured in 1989 and 1995 respectively 94.2% and 91.5%. We also discuss reports of various failure modes of suspension-type porcelain insulators.

• Communications for Statistical Applications and Methods
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• v.17 no.3
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• pp.423-440
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• 2010

The purpose of this paper is to prepare the department creation and the staff increase of education institution by forecasting the demand of health and welfare workers according to execution of the elderly's long-terms treatment insurance system in July, 2008. We estimated confirmors of the elderly's long-terms treatment and the demand of professional workers of health and welfare field due to the increase of care insurance users in facilities treatment organization, care at home service facilities, and family allowance facilities for 2010-2030. The numbers of social welfare professional worker are estimated as 16,624 workers in 2020 and 24,688 workers in 2030. The numbers of nurses are forecasted as 11.287 in 2020 and 16,624 in 2030, we expect that the increase of the demand be accelerated. The demand of necessary care probation worker is 44,824 in 2009, but we already trained over around 500,000 workers in 1,078 education institutions through one year in Aug. 31, 2009, which excesses over the numbers of workers demanded as much as 10 times.

• Journal of Nutrition and Health
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• v.41 no.4
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• pp.291-298
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• 2008

To study antioxidant role of zinc, the effects of dietary zinc deficiency and vitamin E supplementation on lipid peroxidation were studied. Levels of zinc and vitamin E in blood and liver were also measured. Forty Sprague-Dawley male rats aging 8 weeks old were used as experimental animals. Zinc deficient diet (Zn, 0 ppm), zinc normal diet (Zn,36.5 ppm), and vitamin E supplemented diet (1,000 IU ${\alpha}$-tocopherol/kg of diet) were used as experimental diet. During the first three weeks, rats were divided into zinc normal (ZnN, 8 animals) and zinc deficient (ZnD, 32 animals) group. Eight rats from each group were sacrificed to get blood and liver after 3 weeks of experiment. The remaining 24 zinc deficient rat were then divided into zinc normal (ZnDN), zinc deficient (ZnDD), vitamin E supplemented (ZnDE) diet groups. After another 3 weeks of experiment, all animals were sacrificed as well. Thiobarbituric acid reactive substanc (TBARS) levels in plasma and liver, conjugated diene levels in liver were measured as lipid peroxidation index. There were no significant differences in food intake, body weight gain, and food efficiency ratio among groups. Weights of liver per 100 g body weight were not significantly different. There were no significant differences in Zn levels in serum. Plasma and liver TBARS level, and liver conjugated diene level were significantly lower in ZnDE than in ZnDN or ZnDD, and significantly higher in ZnDD than in ZnDN. Therefore, it seems that lipid peroxidation is accelerated by dietary zinc deficiency and recovered partly by vitamin E supplementation.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.337-347
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• 2006

Papers made from unbleached and bleached bagasse chemimechanical pulp were chemically modified by acetylation. The effects of irradiation on unbleached and bleached also reduced papers of bagasse chemimechanical pulp before and after acetylation were investigated in this study. Chemimechanical pulp was prepared from bagasse and then bleached with hydrogen peroxide. Unbleached and hydrogen bleached pulps were reduced by Sodium borohydride in different procedures. Paper sheets were prepared from pulps and then acetylated using a technical grade of acetic anhydride. Accelerated photo-aging was run on the samples using fluorescent lamps to verify photo-stability of paper sheets before and after pretreatments. Brightness reversion (as Post-color number) and other optical properties of the paper sheets were measured. Efficient inhibition of photo-yellowing of papers made from bagasse CMP was achieved by acetylation. The acetylated unbleached CMP was noticeably photo-bleached during irradiation. Sodium borohydride reduction followed by acetylation had the same effect as acetylation alone at the same degree of reaction time and reductive treatment did not affect the yellowing rate to any great extent. The pre-reduced, acetylated unbleached papers were, however, not brightened during irradiation. Calculation done by Kubelka-Munk equation showed that reductive treatment had little effect in reducing the photo-yellowing of paper made from CMP pulp; a small stabilization effect was observed in the case of bleached CMP, while unbleached CMP was slightly more prone to discolor in the later phase of photo-reversion. The improved stability towards light may was closely related to the decrease in the phenolic hydroxyl content as a result of blocking by acetyl groups during treatment with acetic anhydride. The results support the hypothesis that phenolic hydroxyl has an important role in the process of photo-reversion of high-yield pulps. The results obtained in this study demonstrate that the acetylation of paper manufactured from peroxide bleached Bagasse CMP significantly retards light-induced discoloration. The inhibition of yellowing is connected with a decrease in the phenolic hydroxyl content of both unbleached and peroxide bleached papers.

• Journal of the Korea Society for Simulation
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• v.29 no.3
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• pp.19-25
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• 2020

The field farming machine is difficult to develop due to its heavy slopes, tough roads and unformatted cultivation by growing crops. In particular, harvesting is a major problem in rural areas in Republic of Korea where aging is accelerated with work requiring a lot of time and manpower. This study seeks to analyze the dynamic characteristics of hot pepper harvester developed to replace manpower, reduce working hours and mechanize harvesting operations. To analyze the dynamic characteristics of a hot pepper harvester, the dynamic program Recurdyn was used and all analysis were performed as case of an empty vehicle. Based on the results, this study can suggest dynamic safety range of multi-purpose driving platform with hot pepper harvester.

• Tribology and Lubricants
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• v.35 no.4
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• pp.222-228
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• 2019

As rubber products such as O-rings, which are also known as packings or toric joints, come in regular, long term contact with liquid fuel, they can eventually swell, become mechanically weakened, and occasionally crack; this diminishes both their usefulness and intrinsic lifetime and could cause leaks during the steady-state flow condition of the fuel. In this study, we evaluate the lifetime of such products through compression set tests of FKM, a family of fluorocarbon elastomer materials defined by the ASTM international standard D141; these materials have great compression, sunlight, and ozone resistance as well as a low gas absorption rate. In this process, O-rings are immersed in the liquid fuel of airtight containers that can be expressed as a compression set, and the liquid fuel leakage in a flow rig tester at variable temperatures over 12 months is investigated. Using the Power Law model, our study determined a theoretical O-ring lifetime of 2,647 years, i.e. a semi-permanent lifespan, by confirming the absence of liquid fuel leakage around the O-ring assembled fittings. These results indicate that the FKM O-rings are significantly compatible for fuel tests to evaluate long-term sealing conditions.