• Journal of Power System Engineering
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• v.20 no.5
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• pp.5-13
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• 2016

This study is on wear damage of the material for a molding machine that be used at finally cutting of metal beam made in roll forming process of vehicle bump beam process line. SKD11 steel was used with the material for cutting mold jig. In the cutting mold jig, Ti diffusion heat treatment after vacuum heat treatment was carried out for upgrade of surface hardness and anti-wear. Also, the heat treatments by various methods were performed to compare the wear damage degree against above the existing heat treatment. Wear loss and friction coefficient were obtained from wear test. And, micro Vickers hardness values were compared with damaged parts or not of cutting mold jig. Micro Vickers hardness value appeared higher at the undamaged part by Ti diffusion heat treatment. The micro Vickers hardness well followed a two-parameter Weibull probability distribution.

• Journal of agricultural medicine and community health
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• v.35 no.1
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• pp.21-35
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• 2010

There are many work-related injuries and diseases of fisheries in Korea. Fishermen have exposed to harmful environment, such as natural disasters, ultraviolet, noise, vibration, organic solvents, ergonomic risk factors, loss of fresh water and food, and psychologic stress. They have suffered from numerous work-related health problems, including musculoskeletal disorders, cardiovascular diseases, infectious diseases, pyschological diseases, decompression sickness, and so on. Sea accidents can cause deaths of fishermen and if sea pollution is occurred, fishermen have a great economic damage. However, the concern of these injuries and diseases has been little because they are small in number and have decreased. Fisheries are important core industries, so the problems of fisheries have to be solved by a government. But work-related injuries and diseases are not investigated properly and accurate diagnoses are not made due to loss of concern. We hope that this article will be a cornerstone to solving the work-related problems of fisheries.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.4
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• pp.23-31
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• 2007

The objective of the study is to prepare input data for FIA (Flood Inundation Analysis) & FDA (Flood Damage Assessment) through rainfall-runoff simulation by HEC-HMS model. For HwaOng watershed (235.6 $km^{2}$), HEC-HMS was calibrated using 6 storm events. Geospatial data processors, HEC-GeoHMS is used for HEC-HMS basin input data. The parameters of rainfall loss rate and unit hydrograph are optimized from the observed data. HEC-HMS was applied to simulate rainfall-runoff relation to frequency storm at the HwaOng watershed. The results will be used for mitigating and predicting the flood damage after river routing and inundation propagation analysis through various flood scenarios.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.149-150
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• 2020

Granting self-sensing performance in a building is an important performance to ensure the degree of damage and safety of the building. Since the current research is being conducted in the state before deterioration loss occurs, it is necessary to confirm whether the self-sensing performance is maintained even in the damaged conductive cement composite. As part of the study, electrical resistance characteristics were analyzed in conductive cement composites in which freeze-thawing and chemical corrosion occurred. As a result, it was found that the change in electrical resistance value due to freeze-thawing was not as large as 1%, and chemical corrosion occurred. It was found that the change in electrical resistance value of the tested specimen increased by about 10%.

• International Journal of Advanced Culture Technology
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• v.7 no.2
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• pp.218-226
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• 2019

In modern society, people live in an environment with artificial or natural noise. Especially, the sound that corresponds to the artificial noise makes the noise itself and affects each other because many people live and work in the city. Sounds are generated by the activities and causes of various people, such as construction sites, aircraft, production machinery, or road traffic. These sounds are essential elements in human life and are recognized and judged by human auditory organs. Noise is a sound that you do not want to hear by subjective evaluation, and it is a loud sound that gives hearing damage or a sound that causes physical and mental harm. In this study, we introduce the method of stimulating the human hearing by finger vibration and explain the advantages of the proposed method in various kinds of a noise environment. And how to improve the sound quality to improve efficiency. In this paper, we propose a method to prevent the loss of hearing loss and the transmission of sound information based on proper signal to noise ratio when using portable IT equipment in various noise environments.

• Korean Journal of Acupuncture
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• v.24 no.1
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• pp.171-187
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• 2007

Objectives : This study was performed to determine if Orostachys japonicus A. Berger herbal acupuncture (OjB) provides the protective effect against the loss of cell viability and DNA damage induced by oxidant in renal proximal tubular cells. Methods : The cell viability was evaluated by a MTT reduction assay and DNA damage was estimated by measuring double stranded DNA breaks in opossum kidney (OK) cells, an established proximal tubular cell line. Lipid peroxidation was determined by measuring malondialdehyde (MDA), a product of lipid peroxidation. Results : H2O2 increased the loss of cell viability in a time-dependent manner, which were prevented by 0.1% OjB. The protective effect of OjB was dose-dependent over concentration range of 0.05-0.5%. H2O2 caused ATP depletion and DNA damage, which were prevented by OjB and the hydrogen peroxide scavenger catalase. The loss of cell viability by H2O2 was not affected by the antioxidant DPPD, but lipid peroxidation by the oxidant was completely inhibited by DPPD. Generation of superoxide and H2O2 in neutrophils activated by phorbol-12,13-dibutyrate was inhibited by OjB in a dose-dependent manner. OjB inhibited generation of H2O2 in OK cells treated with antimycin A and exerted a direct H2O2 scavenging effect. Exposure of OK cells to 1 mM tBHP caused a significant depletion of glutathione which was prevented by OjB. OjB accelerated the recovery in cells cultured for 20 hr in normal medium without oxidant following oxidative stress. Conclusions : These results suggest that OjB exerts the protective effect against oxidant-induced cell injury and its protective effect was resulted from radical scavenging and antioxidant activities.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.265-282
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• 2000

Despite manufacturers' effort to provide safe and reliable products, a number of product-related accidents occur all over the world resulting in much damage to property, personal injury and even loss of life. Considerable evidence indicates that some accidents arise from user negligence, but most are due to the design, manufacture, and distribution of unreasonably dangerous products when compared to their use. As a result, a tremendous number of product liability lawsuits have been filed, many times causing huge amount of financial damages to manufacturers. Furthermore, with increasing government regulation and growing power of consumer lobbies, manufacturers might be more exposed to product liability claims in the future than now. The objectives of this study are twofold: to provide a framework of future research on product liability and safety and to introduce a product safety policy. To accomplish these objectives, previous studies on product liability and safety were reviewed thoroughly. The product safety policy consists of two parts: (1) an engineering design strategy for reducing product-related risks and (2) a management program for a product liability loss prevention plan. The policy is essential to preventing manufacturers' liability exposure as well as designing a safer product.

• Computers and Concrete
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• v.2 no.5
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• pp.367-380
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• 2005

Recent earthquakes have shown that many of existing buildings in Iran sustain heavy damage due to defective seismic details. To assess vulnerability of one common type of buildings, which consists of low rise framed concrete structures, three defective and three standard columns have been tested under reversed cyclic load. The substandard specimens suffered in average 37% loss of strength and 45% loss of energy dissipation capacity relative to standard specimens, and this was mainly due to less lateral and longitudinal reinforcement and insufficient sectional dimensions. A relationship has been developed to introduce variation of plastic length under increasing displacement amplitude. At ultimate state, the length of plastic hinge is almost equal to full depth of section. Using calibrated hysteresis models, the response of different specimens under two earthquakes has been analyzed. The analysis indicated that the ratio between displacement demand and capacity of standard specimens is about unity and that of deficient ones is about 1.7.

• Korean Journal of Human Ecology
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• v.2 no.1
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• pp.142-148
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• 1999

Tencel fabrics were treated with cellulase after mechanical prefibrillation treatment. SEM analysis was carried out to study morphological change of the treated fabric. The cellulase-treated Tencel fabrics were evaluated for weight loss and tensile strength. X-ray diffraction method, moisture regain, and K/S value were used to elucidate crystalline structural changes occurred by cellulase treatment. Degree of polymerization and copper number of the cellulase-treated fabrics were also measured to estimate effect of hydrolysis. SEM analysis indicated that with treatment of prefibrillation and cellulase, fibrils were produced and damage occurred deep into the fiber. Increases in concentration and time of cellulase treatment increased weight loss and decreased tensile strength retention of the treated fabrics. As cellulase hydrolysis progressed, degree of crystallinity, moisture regain and K/S value were not much changed. (Korean J Human Ecology 2(1) : 142∼148, 1999)

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.75-76
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• 2015

This study has examined the impact resistance and blast resistance characteristics of HPFRCC as a research on impact resistance and blast resistance characteristics using high volume mortar and high velocity projectile for evaluating the protection performance of actual buildings as small quantity experiment of laboratory conditions is performed although there was an instance of performing research on mortar that has reinforced fiber followed by the rise of problems on the damage of human life and buildings created due to explosion and shock. As a result, the destruction loss area and depth have decreased in case of the surface compared to the rear side. As tensile strength and tenacity have increased with the increased fiber replacing ratio, a tendency of destruction loss area and depth getting decreased was shown as the impact resistance has increased.