• 한국운동역학회지
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• 제20권3호
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• pp.337-344
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• 2010

This study was conducted on male college students with pronated foot to measure the foot pressure by having them wear three kinds of mid-sole wedge ($0^{\circ}$, $5^{\circ}$, $10^{\circ}$). Maximum force, foot contact area, mean pressure and peak pressure were measured using a foot pressure distribution measuring instrument. And the surface of the foot sole was divided into 10 areas. Regarding maximum force, there were statistically significant difference in the area 3 of the middle foot(p<.05). Regarding the foot contact area, it appeared broad in the outside area(1, 3, 5) of the foot according to mid-sole wedge, and there was statistically significant difference in the area 1 of the rear foot(p<.05) and the area 3 of the middle foot(p<.05). Mean pressure by foot area decreased in the inside of the foot according to mid-sole wedge, and there was statistically significant difference in the area 2 of the rear foot(p<.05) and the area 3 of the middle foot(p<.05). Regarding the peak pressure by foot area, the pressure roughly decreased in the inside area(2, 4, 7) of the foot according to mid-sole wedge, and there was statistically significant difference in the area 1(p<.05), 2(p<.05) of the rear foot and the area 3 of the middle foot(p<.05).

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.59-64
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• 2009

The propeller induced forces acting on a hull are surface forces and bearing forces. The bearing forces are the forces acting directly on the propeller which are transferred to the hull through the propeller bearings. The surface forces are those which act by fluid pressure directly on the various hull surfaces. Because the surface force is main source to oscillate stern constructions and deckhouse, the estimation of surface force is very important to predict response of forced vibration of that. The estimation methods were statistical analysis method, theoretical analysis method and method through model test.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1042-1047
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• 2001

A mechanistic model is developed to predict the thrust force and cutting torque of drilling process including wear. A mechanistic oblique cutting force model is used to develop the drilling force model. The cutting lips are divided into small elements and elemental forces are calculated by multiplying the specific cutting pressure with the elemental chip area. The specific cutting pressure is a function of chip thickness, cutting velocity, rake angle and wear. The total forces are then computed by summing the elemental forces. Measured cutting forces are in good agreement with the simulated cutting forces.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1202-1208
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• 2006

This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

• 대한치과교정학회지
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• 제22권2호
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• pp.297-308
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• 1992

The effect of orthodontic force on the collagenase and phosphatase activities of the adjacent alveolar bone was evaluated. Maxillary canines of male cats were treated orthodontically with closed coil spring so as to exert about 80g force. Sixteen cats were equally divided into one control group and seven experimental groups (12 hrs, 24 hrs, 36 hrs, 2 days, 3 days, 5 days and 7 days after orthodontic treatment). After sacrificing all animals on experimental intervals, collagenase, acid phosphatase (ACP) and alkaline phosphatase (ALP) activities were determined in the pressure and tension sides of alveolar bones. ACP activities increased in both the pressure and tension sides, but significantly increased in the pressure side continuously. ALP activities increased in the tension side at early stage (1-2 days after treatment), but changed small amount in the pressure side. Collagenase activities increased in the pressure side, especially at late stage (5-7 days after treatment). These results suggest that (1) orthodontic fore force increases the ACP, ALP and collagenase activities generally and (2) activities of ACP and collagenase increase in the pressure side, but that of ALP in the tension side and (3) activities of ACP and ALP increase at early stage, but that of collagenase at late stage after orthodontic treatment. Therefore it is shown that there are time differences in the formation and destruction of organic and inorganic components in the bone metabolism of alveolus with application of the orthodontic forces.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.357-364
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• 2004

A computational study on the supersonic flow around the lateral jet controlled missile has been performed. Case studies have been performed by comparing the normal force coefficient and the moment coefficient of a missile body for several different jet flow conditions, angle of attacks, circumferential jet locations, and spouting jet angles. For the several different jet flow conditions, which include the jet pressure, the jet Mach number, and the corresponding jet mass flow rate, the results show that the normal force coefficient is almost proportional to the jet thrust but the moment coefficient is not. Distinctly different flow phenomena can be noticed as the pressure ratio and the jet Mach number increase. By investigating the angle of attack effect to the normal force and the pitching moment, it has been identified that the normal force and the pitching moment show nonlinearity with respect to the angle of attack. From the detailed flow field analyses with respect to the jet flow conditions and the angle of attacks, it is verified that most of the normal force loss and the pitching moment generation are taken place at the low-pressure region behind the jet nozzle. Furthermore, the normal force and the pitching moment characteristics of the missile have been identified by comparing different circumferential jet locations and spouting jet angles.

• The Journal of Korean Physical Therapy
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• 제23권6호
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• pp.15-22
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• 2011

Purpose: This research investigated falls due to obstacles that occur among elderly people by assessing changes in the values of plantar foot force, peak force, and plantar foot pressure in elderly subjects while they were stepping over obstacles of different heights. Methods: The subjects were 20 elderly people aged 70-80 years; Pressure was measured on flat ground(0 cm), and after installing obstacles of 8 cm and 12 cm using the F-scan system, which is a resistance-type pressure sensor. A one-way analysis of variance was performed to compare pressure on each part of the foot according to various heights after collecting data using the Tekscan program. The least significant difference test was used for the post-hoc analysis, A p-value <0.05 was considered significant. Results: The force value for the toe area (parts 1, and 2) and contact pressure increased significantly with the 12 cm obstacle (p<0.05). The peak force value and the peak contact pressure for part 1 increased significantly with the 12 cm obstacle (p<0.05). Conclusion: Larger changes appeared in the functions and structure of the foot while subjects walked over obstacles of different heights compared to flatland walking. This result suggests that people have safety strategies to prevent falls, and that there is a need for a more realistic approach through practice to overcome obstacles of various heights to prevent falls.

• 대한토목학회논문집
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• 제28권2C호
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• pp.105-115
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• 2008

다양한 지층에 설치된 대형 뉴메틱케이슨의 강성기초에 작용하는 접지압분포를 파악하기 위하여 영종대교하부기초로 채택된 뉴메틱케이슨 시공시 실시한 현장계측자료를 분석하였다. 뉴메틱케이슨의 침설시 케이슨의 하부 접지면에 케이슨의 침설에 저항하여 저항력이 작용할 것이다. 이 저항력을 뉴메틱케이슨 기초저면 모서리에 설치한 반압계로 측정할 수 있었다. 그리고 이 저항력측정기록을 이용하여 접지압을 산정하였다. 측정기록의 분석결과 기반암구간에서 뉴메틱케이슨기초에 작용하는 접지압분포는 아래로 볼록한 형상의 접지압분포를 보이는 반면에 해성퇴적층과 풍화암층에서의 접지압분포는 위로 볼록한 형상을 보인다. 그리고 이들 접지압분포는 대체적으로 모든 지층에서 대칭분포를 나타내고 있다. 대형 뉴메틱케이슨기초에 작용한 최대접지압에 의하여 제시된 접지압분포는 Kgler(1936)와 Fang(1991)이 강성기초를 대상으로 제시한 접지압분포특성과 잘 일치하는 것으로 나타났다.

• 한국전산유체공학회지
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• 제7권3호
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• pp.1-8
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• 2002

The counter jet flow which is injected against the free stream at stagnation region of blunt body for improvement of aerodynamic performance has been studied by using upwind Navier-Stokes method. The variations of drag force and upwind forward penetration depth due to changes in the stagnation thermodynamic properties of counter jet flow such as total pressure, Mach number, and total temperature have been studied. The results show that the changes in the stagnation pressure and Mach number have large effects on the wall pressure and drag force, but the total temperature does not affect the wall pressure and drag force.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.373-376
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• 2002

The drift force acting on a floating OWC chamber in waves is studied taking account of fluctuating air pressure in the air chamber. A velocity potential in the water due to the free surface oscillating pressure patch is added to the conventional radiation-diffraction potential problem. The potential problem inside the chamber is formulated by making use of the Green integral equation associated with the Rankine Green function while the outer problem with the Kelvin Green function. The drift forces as well as the chamber motions are calculated taking account of the air pressure in the chamber.