• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.51-54
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• 2007

Surfactants can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for hexadecyl pyridinium bromide over the range $40^{\circ}C$ to $60^{\circ}C$ has been measured by drop methods. Thermodynamic quantities for micellization of hexadecyl pyridinium bromide in water have been calculated by polynominal equation.

• Journal of the Korea Safety Management & Science
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• v.9 no.5
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• pp.37-41
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• 2007

There are two parts(middle and southern) according to dividing line of district in Korea. Middle part contains Kang Won, Chung Chung, Gyeong Gi, Seoul, In Cheon and Dae Jeon. Southern part contains Gyeong Sang, Jeol La, Je Ju, Bu San, Dae Gu, Ul San, and Gwang Ju. It is known that there are some differences between middle and southern part on weather. The climatic differences might affect human body. Thus, the mall objective of this study is to analyze effects of climatic differences which influence somatotype characteristics on residents in two regions. In order to compare and analyze data, $R\ddot{o}hrer$ index and drop-value were used. Also, this paper provides typical ratios according to dividing line of district.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.120-126
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• 1993

This work was carried out to investigate the effects of solid mass flow rate, mean particle diameter and mesh number of screen packing material on minimum carrying velocity, which defined as the superficial gas velocity of the upper limit of chocking phenomenon. Vertical pneumatic conveying was studied on a 4.6cm 1. D. pipe, 180cm in length. Experiments were performed in both the empty and the screen-packed pipe. It was also examined the effect of superficial gas velocity, solid mass flow, mean particle diameter, and mesh number of packing material on pressure drop. Minimum carrying velocity in screen packed-pipe was lower than that in an empty pipe. besides minimum carrying velocity was decreased with increase in mesh number of screen packing material. The pressure drop In vortical packed-pipe was Increased with superficial gas velocity, mean particle diameter, and mesh number of screen packing material.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.353-359
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• 2008

Somatotype is a very important factor for the comfortable and safe work environments. Many researches are trying to find the characteristics of somatotype according to age. Thus, the main objective of this study is to analyze somatotype of male residents in Seoul. The data used in this study included 267 men subjects who are living in Seoul. In order to analyze a detailed somatotype of citizens, age groups are divided into six groups. In order to compare and analyze data, Coefficient of Variance, Cronbach's Alpha, $R\ddot{o}hrer$ Index and Drop Value were used in this study. The results of this study can be applied to the comfortable and safe work environments for workers.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.133-149
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• 2022

The design of a wooden impact limiter equipped to a transportation cask for radioactive materials was optimized. According to International Atomic Energy Agency Safety Standards, 9 m drop tests should be performed on the transportation cask to evaluate its structural integrity in a hypothetical accident condition. For impact resistance, the size of the impact limiter should be properly determined for the impact limiter to absorb the impact energy and reduce the impact force. Therefore, the design parameters of the impact limiter were optimized to obtain a feasible optimal design. The design feasibility criteria were investigated, and several objectives were defined to obtain various design solutions. Furthermore, a probabilistic approach was introduced considering the uncertainties included in an engineering system. The uncertainty of material properties was assumed to be a random variable, and the probabilistic feasibility, based on the stochastic approach, was evaluated using reliability. Monte Carlo simulation was used to calculate the reliability to ensure a proper safety margin under the influence of uncertainties. The proposed methodology can provide a useful approach for the preliminary design of the impact limiter prior to the detailed design stage.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.3
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• pp.172-179
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• 2021

The drop impact analysis was carried out on Type 4 pressure containers, and the degree of damage to the falling environment was predicted and determined using smoothed particle hydrodynamics (SPH) techniques. The purpose of the design and the optimization process of the winding pattern of the pressure vessel of the composite material is to verify the safety of the container in actual use. Finally, an interpretation process that can be implemented in accordance with domestic test standards can be established to reduce the cost of testing and containers through pre-test interpretation. The research on the fall analysis of pressure vessels of composite materials was conducted using Abaqus, and optimization was conducted using ISIGHT. As a result, the safety of composite pressure vessels in the falling environment was verified.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.2
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• pp.104-107
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• 2009

It was verified that the effect of the distance between current input point and output point on direct current potential drop(DCPD) in the material with two-dimensional surface notch. If the distance between potential drop measuring points was fixed at a certain distance, the potential drop was decreased with increasing the distance between current input and output points. Hence it is the effect way to increase sensitivity in DCPD that the current input and output points should be located near the potential measuring points. DCPD was a useful method for surface crack sizing because the potential drop was proportional to the length of notch. When the current input and output points are located near the potential measuring points, even small length crack can be measured by DCPD technique.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.217-225
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• 2009

The study on the left turning trajectory has not done many times in Korea. Because of this, there are a lot of intersections built without considering on turning trajectory of vehicles, in Korea, and we can see many conflicts, reduced capacity of turn, especially at small intersections. Even if left turn trajectory is designed well, it is not easy to mark exactly on the pavement according to the turn trajectory. This study suggests "drop Islands" which can be seen in Europe, and is introduced in Korea recently, to solve the problems of conflicts and reduced capacity of turning. It suggests a table of location of the stop line so that the engineers who design the intersection design appropriate left turn trajectory and marking of the stop line and turn trajectory is done more exactly. To evaluate the effect of "drop island", two intersections with and without drop island were compared on the turnning radii and location of stop line. Construction of "drop island" can increase the capacity of intersection and safety without additional land and construction expenses.

• Journal of Pharmacopuncture
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• v.12 no.3
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• pp.61-72
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• 2009

Objectives : This experimental study was performed to investigate the safety and efficacy of Bovis Calculus pharmacopuncture solution manufactured with freezing dryness method to use eye drop. To identify the use of it as eye drop, the eye irritation test of rabbits and the antibacterial test of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, and Candida albicans were performed. Methods : 1. The eye irritation test of this material was performed according to the Regulation of Korea Food & Drug Administration(2005. 10. 21, KFDA 2005-60). After Bovis Calculus pharmacopuncture solution was administered in the left eye of the rabbits, eye irritation of the cornea, iris and conjunctiva was observed at 1, 2, 3, 4 & 7day. 2. After administering Bovis Calculus pharmacopuncture solution on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) which cause Keratitis, MIC(Minimum Inhibition Concentration) and the size of inhibition zone were measured. Anti-bacterial potency was also measured using the size of inhibition zone. Results : 1. After Bovis Calculus pharmacopuncture solution was administered in the left eye of the rabbits, it was found that none of nine rabbits have abnormal signs and weight changes. 2. After Bovis Calculus pharmacopuncture solution was medicated in the left eye of the rabbits, no eye irritation of the cornea, iris and conjunctiva was observed at 1, 2, 3, 4 & 7day. 3. There was no response to MIC on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) after Bovis Calculus pharmacopuncture solution was medicated. Conclusions : The present study suggests that Bovis Calculus pharmacopuncture solution is a nontoxic and non-irritant medicine, which does not cause eye irritation in rabbits, but dosen't have antibacterial effects on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) which cause Keratitis. These study result recommends that more research on other herbal medicines of eye drop for Keratitis are required.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.274-279
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• 2010

The present work is to analyze the longitudinal static stability and the drop trajectory of fighter aircraft's external fuel tank, of which horizontal fin is modified as the 20% scale down size compared with the original one. The analytical results to the pitching stability of external fuel tank using a thin airfoil's aerodynamic force data show the corresponding tendency to results of wind tunnel experiment. Results of trajectory simulation by the 6 degree of freedom equations of motion, comparing with drop trajectories of wind tunnel experiment, are shown that aircraft's attitude affects strongly on horizontal movement but not on the vertical movement. Those results give the reliability to aircraft safety when the external fuel tank with the 20% reduced horizontal fins is released from aircraft based on the flight manual.