• 대한통합의학회지
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• 제10권2호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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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 $45{\sim}52dB(A)$.

• 한국안전학회지
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• 제27권5호
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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%.

• 한국안전학회지
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• 제28권4호
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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.%.

• 한국안전학회지
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• 제29권3호
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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.%.

• 한국안전학회지
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• 제16권4호
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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.

• 한국정밀공학회지
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• 제8권3호
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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.

• 한국화재소방학회논문지
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• 제22권3호
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• pp.228-233
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• 2008

폭굉한계는 가연성물질의 화재 및 폭발 위험성을 결정하기 위해 사용되는 중요한 연소 특성치 가운데 하나이다. 본 연구에서는 가연성혼합물의 구성하는 각 순수성분의 연소열과 기상 조성을 이용하여 폭발한계를 예측하였다. 제시된 방법론에 의한 계산값은 적은 오차범위에서 문헌값과 일치하였다. 따라서 본 연구에서 제시한 방법론이 다른 가연성물질의 폭굉한계 예측에 폭넓게 적용되기를 기대한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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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.

• 한국화재소방학회논문지
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• 제27권2호
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• pp.11-17
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• 2013

노말언데칸의 안전한 취급을 위해서 하부인화점, 상부인화점, 연소점 그리고 발화지연시간에 의한 발화온도를 측정하였다. 또한 노말언데칸의 하부와 상부인화점의 측정값을 이용하여 폭발하한계와 상한계를 예측하였다. 밀폐식 장치에 의한 노말언데칸의 하부인화점은 $59^{\circ}C$와 $67^{\circ}C$로 측정되었고, 개방식 장치에 의한 하부인화점은 $67^{\circ}C$와 $72^{\circ}C$로 측정되었다. 클리브랜브 장치에 의한 노말언데칸의 연소점은 $74^{\circ}C$로 측정되었다. ASTM E659-78 장치를 사용하여 자연발화 온도와 발화지연시간을 측정하였고, 여기서 측정된 최소자연발화온도는 $198^{\circ}C$였다. 측정된 하부인화점 $59^{\circ}C$와 상부인화점 $83^{\circ}C$를 이용하여 예측된 폭발하한계는 0.65 Vol.%, 폭발상한계는 2.12 Vol.%였다.