• Journal of The Korean Society of Integrative Medicine
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• v.10 no.2
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• pp.203-210
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• 2022

Purpose : The purpose of this study was to investigate the effect of vestibular sensory stimulation exercise on the limit of stability, dynamic weight shift, and upper and lower extremities reaction time in adult women. Methods : This study was conducted with 30 female. All subjects were randomly and equally assigned to an experimental group and a control group of 15 each. Subjects assigned to the experimental group received vestibular sensory stimulation training for 6 weeks. For the intervention, vestibular sensory stimulation exercises were conducted by referring to the Hamid exercise method and the Cawthorne-Cooksey exercise method, and the control group did not receive any intervention. All subjects were tested for limit of stability, dynamic weight shift, and upper and lower extremities reaction time before and after the intervention. Results : The results of this study showed significant differences between groups in reaction time, moving velocity, and directional control in the limit of stability test after intervention. In the dynamic weight shift test after intervention, there was a significant difference between the groups in the slow directional control of left and right. And in the upper and lower extremities reaction time test after intervention, both scores and reaction time showed significant differences between groups. Conclusion : As a result, the three vestibular sensory stimulation exercises applied in this study improved the limit of stability, dynamic weight shift, and upper and lower extremities reaction time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.547-552
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• 2002

The purpose of this study is to propose indoor noise level in residential buildings affected by transportation noise (road traffic, railway and air-craft noise) based on subjective evaluations, 30 subjects participated in the experiment to evaluate the noise. Experimental environment reproduced real living and office environment, and in asking subjects' annoyance to the noise. An experiment to investigate the subjective responses to various computer noises (CD-Rom, HDD, Fan) in office environment was also undertaken. The Result shows that the lower limit of transportation noise is $40{\sim}41dB(A)$ and upper limit is $55{\sim}60dB(A)$, whereas the lower limit of various computer noises is $36{\sim}40dB(A)$ and upper limit is $45{\sim}52dB(A)$.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.70-76
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• 2012

For the safe handling of n-tetradecane, the lower flash points and the upper flash point, fire point, AITs (auto-ignition temperatures) by ignition delay time were experimented. Also lower and upper explosion limits by using measured the lower and upper flash points for n-tetradecane were calculated. The lower flash points of n-tetradecane by using closed-cup tester were measured $104^{\circ}C$ and $112^{\circ}C$. The lower flash points and fire point of n-tetradecane by using open cup tester were measured $113^{\circ}C$ and $115^{\circ}C$, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-tetradecane. The experimental AIT of n-tridecane was $207^{\circ}C$. The calculated lower and upper explosion limit by using measured lower $104^{\circ}C$ and upper flash point $140^{\circ}C$ for n-tetradecane were 0.63 Vol.% and 3.18 Vol%.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.53-57
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• 2013

For the safe handling of n-pentadecane, the lower flash points and the upper flash point, fire point, AITs(auto-ignition temperatures) by ignition delay time were experimented. Also lower and upper explosion limits by using measured the lower and upper flash points for n-pentadecane were calculated. The lower flash points of n-pentadecane by using closed-cup tester were measured $118^{\circ}C$ and $122^{\circ}C$. The lower flash points and fire point of n-pentadecane by using open cup tester were measured $126^{\circ}C$ and $127^{\circ}C$, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-pentadecane. The experimental AIT of n-pentadecane was $195^{\circ}C$. The calculated lower and upper explosion limit by using measured lower $118^{\circ}C$ and upper flash point $174^{\circ}C$ for n-pentadecane were 0.54 Vol.% and 6.40 Vol.%.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.39-45
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• 2014

For the safe handling of n-hexadecane, the lower flash points and the upper flash point, fire point, AITs(auto-ignition temperatures) by ignition delay time were experimented. Also lower and upper explosion limits by using measured the lower and upper flash points for n-hexadecane were calculated. The lower flash points of n-hexadecane by using the Setaflash and the Pensky-Martens closed testers were measured $128^{\circ}C$ and $126^{\circ}C$, respectively. The lower flash points of the Tag and the Cleveland open cup testers were measured $136^{\circ}C$ and $132^{\circ}C$, respectively. The fire points of the Tag and the Cleveland open cup testers were measured $144^{\circ}C$. respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-hexadecane. The experimental AIT of n-hexadecane was $200^{\circ}C$. The calculated lower and upper explosion limit by using measured lower $128^{\circ}C$ and upper flash point $180^{\circ}C$ for n-hexadecane were 0.42 Vol.% and 4.70 Vol.%.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.109-114
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• 2001

Explosive characteristics of the city gas were determined by using the gas explosion apparatues. The explosive range is determined between lower explosive limit of 5.0% and upper explosive limit of 15.3% at atmosphere and even though the oxygen concentration is decreased, lower explosive limit is not changed, but upper explosive limit is rapidly decreased. The minimum oxygen for combustion is determined 10%. The maximum explosion pressure is determined 5.72$\textrm{cm}^2$ and the maximum rate of explosion pressure rise is oxygen concentration of 12% to determined 160.12$\textrm{cm}^2{\cdot}$sec.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.93-104
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• 1991

Limit analysis is based on the duality theorem which equates the least upper bound to the greatest lower bound. In this study, limit analysis of axisymmetric forming problem with workhardening materials is formulated by minimizing the upper bound functional and finite element program is developed for forward estrusion. Limit loads, velocity and flow line fields are directly obtained under various process conditions and deformation characteristics such as strains, strain rates and grid distortion are obtained from the optimum velocity components by numerical calculation. The experimental observation was carried out for extrusion and compared with computed results. The good agreement between theoretical and experimental results is shown that the developed programming is very effective for the analysis of axisymmetric extrusion.

• Fire Science and Engineering
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• v.22 no.3
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• pp.228-233
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• 2008

Detonation limit is one of the major physical properties used to determine the fire and explosion hazards of the flammable substances. In this study, the lower detonation limits (LDL) and the upper detonation limits (UDL) of the flammable substances predicted with the appropriate use of the heat of combustion and the stoichiometric coefficient. The values calculated by the proposed equations were a good agreement with literature data within a few percent. From a given results, It is to be hoped that this methodology will contribute to the estimation of the detonation limits of for other flammable substances.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.481-485
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• 2000

A new type of compliant press-fit pin has been developed and evaluated for use packaging of electronic telecommunications equipments. Main requirements for design are defined the upper limit of pin insertion force and the lower limit of pin retention force. Upper limit of pin insertion force is set to protect the copper plate of the inner PTH wall. Lower limit of pin retention force is set to satisfy a wire-wrapping specification. Results are represented by insertion force and retention force variations according to the front angle, rear angle and material, etc.

• Fire Science and Engineering
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• v.27 no.2
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• pp.11-17
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• 2013

For the safe handling of n-undecane, the lower flash points and the upper flash point, fire point, AITs (auto-ignition temperatures) by ignition delay time were experimented. Also lower and upper explosion limits by using measured the lower and upper flash points for n-undecane were calculated. The lower flash points of n-undecane by using closed-cup tester were measured $59^{\circ}C$ and $67^{\circ}C$. The lower flash points of n-undecane by using open cup tester were measured $67^{\circ}C$ and $72^{\circ}C$, respectively. The fire point of n-undecane by using Cleveland open cup tester was measured $74^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-undecane. The experimental AIT of n-undecane was $198^{\circ}C$. The estimated lower and upper explosion limit by using measured lower flash point $59^{\circ}C$ and upper flash point $83^{\circ}C$ for n-undecane were 0.65 Vol.% and 2.12 Vol.%.