• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1171-1178
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• 1992

An experiment was performed to describe the heat and mass transfer occurring between hot waste gas and cold water through direct contact in a direct contact heat exchanger. This model was then used to obtain an equation of overall heat transfer coefficent based on heat exchanger volume. The diffusion heat transfer rate is 2-3 times larger than the convection heat transfer rate as results of condensation of the water vapor contained in the waste gas. The boiler efficiency increases over 10%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.341-348
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• 2001

In this study, nonlinear vibration analysis of the cylindrical orthotropic porous thin plate under V-shaped tension distribution with wire impact damping is considered. We make dynamic model of the plate under the tension using commercial FEM code and reduce the number of its degrees of freedom using dynamic condensation. The dynamic model of wire is obtained as lumped mass model from string equation. And then we analyze the nonlinear vibration of the plate including the impact phenomenon between the plate and the wire using the reduced mass and stiffness matrices of the plate and lumped model of the wire. The contact phenomenon between them can be described by impact contact elements composed of contact stiffness coefficients from Hertzian contact theory and contact damping coefficients from restitution coefficient between them. And we discussed the results of nonlinear vibration analysis for variations of their design parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.547-548
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• 2009

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1121-1127
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• 2010

Human characteristic responding to idle vibration on passenger vehicle was studied to find if affected by seating posture of passenger. When twelve male subjects are exposed to moderate vertical vibration of 0.224 $m/s^2$ r.m.s. at frequency range from 3 Hz to 40 Hz, it was found that seating posture significantly affects to biodynamical characteristics, apparent mass and apparent eccentric mass, at most range of idle vibration frequency(20~40 Hz). The supported thigh contact on rigid seat showed bigger values in the two biodynamical characteristics than the average thigh contact. The bigger apparent mass and apparent eccentric mass in the seating posture of the supported thigh contact can be assumed more strengthened muscle at the frequency range.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.145-149
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• 2012

I describe a series of processes, including hierarchical fragmentation, gravitational scattering, Kozai cycles within triple systems, tidal friction and magnetic braking, that I believe are responsible for producing the modest but significant fraction of stars that are observed as contact binaries. I also discuss further processes, namely heat transport, mass transport, nuclear evolution, thermal relaxation oscillations, and further magnetic braking with tidal friction, that influence the evolution during contact. The endpoint, for contact, is that the two components merge into a single star, as recently was observed in the remarkable system V1309 Sco. The single star probably throws off some mass and rotates rapidly at first, and then slows by magnetic braking to become a rather inconspicuous but normal dwarf or subgiant. If however the contact binary was part of a triple system originally-as I suggested above was rather likely-then the result could be a $widish$ binary with apparently non-coeval components. There are several such known.

• Journal of Astronomy and Space Sciences
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• v.22 no.3
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• pp.233-242
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• 2005

The absolute dimensions and orbital elements of 66 near contact binaries, collected from literatures, have been analyzed to investigate the physical characteristics of the near contact binaries as well as co-relations among physical parameters. The relationship between the mass ratio and luminosity ratio of the near contact binary systems have been obtained as a $L_2/L_1{\approx}(M_2/M_1)^{1.45}$, which is similar to that of the early type contact binary system. The physical parameters of the new contact binaries show that the difference in mass, radius, luminosity and temperature between the primary and the secondary components for the F type NCBs are smaller than those for the A type NCBs. In H-R diagram, the components of the A types are located closer to the terminal age main sequence than those of the F types.

• Structural Engineering and Mechanics
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• v.4 no.3
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• pp.303-312
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• 1996

The dynamic behavior of an Euler beam with multiple point constraints traversed by a moving concentrated mass, a "moving-force moving-mass" problem, is analyzed and compared with the corresponding simplified "moving-force" problem. The equation of motion in matrix form is formulated using Lagrangian approach and the assumed mode method. The effects of the presence of intermediate point constraints in reducing the fluctuation of the contact force between the mass and the beam and the possible separation of the mass from the beam are investigated. The equation of motion and the numerical results are expressed in dimensionless form. The numerical results presented are therefore applicable for a large combination of system parameters.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.2
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• pp.180-188
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• 1994

The purpose of this study was to evaluate the effect of basic needs and demographic variables of adult woman on the modesty and aethetics In the selection of clothes. The results of the study were as follows: 1. There are factors which have effect on variables of need. School careers have effect on physical need. Age, marriage status and household type have effect on safty need. Native community and household type have effect on self-esteem. School career, native community, household type and frequency of contact with mass media have effects on need of self-actualizing and native community has effect on the aesthetic need. 2. Physical bleed, self-esteem, self-actualization, safety need, fiequency of contact with mass media, age, native community and income have direct effect on the modesty of clothing. 3. Aethetic and self-actualization need, frequency of contact with mass media and income have direct effect on the aethetics of clothing.

• Tribology and Lubricants
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• v.16 no.4
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• pp.289-294
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• 2000

This paper present the contact stresses, which considers the shear stress at the cam and follower interface in the direct acting type valve train system of a high speed engine. To determine the contact condition, the normal contact forces are calculated by using the lumped mass dynamic modeling. The line contact is considered between the cam and follower interface. The variations of dynamic stresses are presented as a function of camshaft rotational angle. Also the effects of various design parameters are investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.870-874
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• 2007

Golf ball spin rate after impact with club is created by the contact force, which is greatly influenced by ball and club mass, material, impact speed, and club loft angle. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of the ball, and the tangential force creates the spin. Especially, the tangential force takes either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail. It is shown in this work that the linear impulse of the tangential force is directly related to generation of back spin rate of golf ball. The linear impulse can be calculated from the tangential force, which depends upon many factors such as ball and club mass, material, impact speed, and club loft angle. In this research, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and the contact time at impact between golf club head and ball are computed using FEM.