• 한국기계가공학회지
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• 제6권2호
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• pp.3-8
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• 2007

Nonlinear property and contact matter are analyzed about the pipe applied with internal pressure through this study. The weakest part and its safety can be examined. Maximum equivalent stress is shown at the contact surface between bolt and nut. The value of contact stress with the pressure of 12MPa is increased 1.4 times as large as that with no pressure. The maximum contact pressure is shown at the clamp corner of the external surface on pipe. The value of contact pressure with the pressure of 12MPa is increased 1.4 times as large as that with no pressure. The radial deformation with no pressure is also increased greatly at the middle part of internal surface on pipe. But this maximum deformation on pipe with the pressure of 12MPa is shown at the part far away the support of pipe. This value is increased 5.7 times as large as that value with no pressure. As contact status, the sticking occurs most at the external surface of pipe. It also tends to occur at the contact surface between bolt and nut. At the external surface of pipe, the sticking in case of the pressure of 12MPa occurs more than that in case of no pressure.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.38-45
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• 2001

Environmental protection on the ocean has been interested and nowadays the International maritime organization(IMO) has advanced on the prevention of air pollution from ships. This study presents the emission characteristics of 4 stroke propulsion diesel engine in E2 cycle (constant speed) and E3 cycle (propeller curved speed). Also the effects of important operating parameters in terms of intake air pressure and temperature, and maximum combustion pressure are described on the specific emissions. Emissions measurement and calculation are processed according to IMO technical code. The results show that NOx emission level in E3 cycle is higher than E2 cycle due to lower engine speed and lower maximum combustion pressure by retarding fuel injection timing. Intake air temperature has strong influence on NOx emission production. And CO, HC emissions are not affected by maximum combustion pressure and intake air pressure and temperature.

• 한국운동역학회지
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• 제25권4호
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• pp.475-482
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• 2015

Objective : The purpose of this study was to investigate mean plantar foot pressure, maximum plantar pressure and ground reaction force, and center migration path of pressure according to the type of trekking shoes for the development of shoes. Method : Subjects of the study averaged $22.10{\pm}2.05years$ of age. Their average height was $169.27{\pm}7.62cm$ and their average weight was $64.34{\pm}10.22kg$. The method of this study was administered measuring 50 steps, at once, 3 times at a speed of 4 km/h and using the data of 30 steps. Pedar-X system measured the mean foot pressure, maximum foot pressure, mean maximum force, and center migration path of pressure by subjects' position while walking. Statistical analysis was performed by SPSS 23.0 using a paired t-test. Results : Results of the study showed Nestfit trekking shoes lower foot pressure of both feet in mean foot pressure and maximum foot pressure. Nestfit trekking shoes showed high ground reaction force (p<.001) in the midfoot, and low mean ground reaction force in the rearfoot. The center migration path of pressure showed the Nestfit trekking shoes were more stable than flat insole trekking shoes. Conclusion : It can be concluded that wearing Nestfit trekking shoes spreads pressure efficiently and induces walking stability because Nestfit trekking shoes spread the pressure of the forefoot and rearfoot to the midfoot and the center migration path of pressure shows regularly.

• 소음진동
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• 제10권5호
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• pp.873-879
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• 2000

Experimental investigation was conducted to study the effects of pitch angle maximum camber on the performance and noise of an axial-flow fan used in outdoor-unit of air -conditioner. For this study the axial-flow fan whose pitch angle can be varied was made and the Specific sound Pressure Level and other coefficients were measured using the anechoic fan tester. It is found that pitch angle affects more severly than the maximum camber on the fan performance. On the while the maximum camber affects much on the specific sound power level. Present results show that it is important to choose the optimum pitch angle and maximum camber to design the high-performance and low-noise axial-flow fan and specific noise measured in the anechoic fan tester can be sued effectively for the design of low-noise fan.

• 대한기계학회논문집B
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• 제22권6호
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• pp.823-831
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• 1998

In order to investigate the impulsive noise at the exit of high-speed railway tunnel and the pressure transients inside the tunnel, numerical calculations using a Total Variation Dimishing difference scheme were applied to axisymmetric unsteady compressible flow field. Some compression wave forms were assumed to model the compression wave produced in real high-speed railway tunnel. The numerical data were extensively explored to analyze the peak over-pressure and maximum pressure gradient in the pressure wavefront. The effect of the distance and cross-sectional area ratio between two-continuous ducts on the characteristics of the pressure waves were investigated. The peak over-pressure inside the second duct decreases for the distance and cross-sectional area ratio between two tunnels to increase. The peak over-pressure and maximum pressure gradient of the pressure wavefront inside the second duct increase as the maximum pressure gradient of initial compression wave increases. The present results were qualitatively well agreed with the results of the previous shock tube experiment.

• 산업기술연구
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• 제8권
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• pp.3-11
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• 1988

Shock pressure of wave breaking on vertical wall is studied experimentally with beaches, which have four different slopes (1/4.02, 1/7.05, 1/10, 1 /13.5). This results is summerized as follows: 1. Maximum impact presures are occured where the wave break directly on the wall rather than breaking in front of the wall. 2. Deep water steepness, and the beach slope are the two Quantities governing the magnitude and location of maximum dimensionless impact pressure from wave breaking directly on the wall, also, the greatest pressure is produced with a beach slope of 1/10. 3. This study is clearly shown that the location of maximum pressure can be presented above still water level under respectively experimental condition. The dimensionless elevation of maximum Pressure is greatest on a beach slope of 1/10.

• Journal of Acupuncture Research
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• 제37권1호
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• pp.28-34
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• 2020

This is a systematic review of the clinical use of cupping therapy. Four domestic databases and 2 foreign databases were searched. Studies that reported the cupping pressure used during cupping therapy were included in this study. The types of cupping, cupping site, pressure, and duration of cupping were the main parameters analyzed. A total of 27 studies, including 24 experimental studies were analyzed. There were 12 constant negative pressure (domestic) studies with a range between 60 mmHg and 600 mmHg. There were 5 maximum negative pressure (domestic) studies and the maximum negative pressure was 620 mmHg. Three studies used a maximum negative pressure of 600 mmHg. There were 4 constant negative pressure (foreign) studies with a range between 75 mmHg to 750 mmHg. There were 3 maximum negative pressure (foreign) studies with a maximum pressure of 420 mmHg. The studies differed with regards to the materials used and the amount of pressure applied. Many studies had limited information and therefore generalizability of the results in this review is limited. Further experimental studies are required to establish the correlation between cupping pressure and treatment effects so that cupping therapy can be standardised.

• 대한기계학회논문집B
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• 제21권10호
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• pp.1294-1302
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• 1997

For the purpose of investigating the impulsive noise at the exit of high-speed railway tunnel and the pressure transients inside the tunnel, experiments were carried out using a shock tube with an open end. A great deal of experimental data were obtained and explored to analyze the peak pressures and maximum pressure gradients in the pressure waves. The effects of the distance and cross-sectional area ratio between two-continuous tunnels on the characteristics of the pressure waves were investigated. The peak pressure inside the second tunnel decreases for the distance and cross-sectional area ratio between two tunnels to increase. Also the peak pressure and maximum pressure gradient of the pressure wave inside the second tunnel increase as the maximum pressure gradient of initial compression wave increases.

• 한국운동역학회지
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• 제28권3호
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• pp.165-173
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• 2018

Objective: The purpose of this study is to provide biomechanical basis data for the analysis of the maximum vertical ground reaction force, the maximum plantar pressure, the average plantar pressure, and the contact area according to the type of the insole through the insole insertion type foot pressure gauge. Method: In the treadmill, the slope was set at 10%, the first type A was worn at a walking speed of 3.5 km / h, and then walking was carried out using B, C, and D types. Data from 20 boots with consistent walking were extracted and plantar pressure data were collected and analyzed. Results: Functional insole was more effective than conventional insole for maximum vertical ground reaction force, maximum plantar pressure, average plantar pressure, and contact area at 10% of treadmill ramps. Conclusion: In this study, D-type insole supports the cushion in the middle part and supports the heel cup with hardness in the hind part, so that it is the most effective insole by lowering the plantar pressure and dispersing it more widely.

• Tribology and Lubricants
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• 제5권2호
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• pp.60-67
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• 1989

For the life prediction and fatigue failure prevention of the constant velocity joint, the maximum equivalent stress and its location in depth from the contact area are essential. These values give the fundamental information to determine the depth of the surface hardening treatment at the contact area. Contact stresses are evaluated at the surface and subsurface of the ball groove of the Weiss type constant velocity joint. The maximum contact pressure and the maximum equivalent stress are obtained. The effects of various parameters such as the radius of ball groove, friction coefficient, and residual stress are studied. The maximum equivalent stress and the maximum contact pressure increase as the radius of the ball grove increases. The location of the maximum equivalent stress moves toward surface as the friction coefficient increases. It was also found that the maximum equivalent stress becomes minimum when the compressire residual stress is about 0.16 times of the maximum contact pressure.