• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3395-3403
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• 1994

The structural test technique and equipment for strength test of astronautical structures, such as rocket, were presented in this paper. Structural strength tests of the fin assembly with fin and fin frame in the scientific sound rocket were performed with load levels of 100% limit load and 150% ultimate load of design lift force. Safety factors in each part of the fin assembly were calculated at these two load levels and the stiffnesses based on the measured deflection of fin assembly and strains on fin and fin frame were evaluated at these two load level. As the result of structural test, the fin assembly was estimated to be safe.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.2
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• pp.92-99
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• 2018

A numerical analysis of a compressor dehumidifier has been conducted focusing on the air side heat transfer, which is a part of a series research on the dehumidifier. The moving reference frame was applied to the fan modeling, and the porous model was used for the evaporator and condenser modeling. Curve fitting obtained the inertial and viscous resistances parameters to the results of the physical model of the unit cell with actual shape of a fin tube. The porous model was validated within a reasonable computation time for the range of practical inlet velocity of a dehumidifier. A parametric study has been conducted for fin number, fan speed (i.e., air flow rate), and evaporator/condenser tube arrangement. ANOVA analysis showed the dependency of each parameter on the velocity and temperature uniformity, which are desirable for high performance of the dehumidifier.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.745-752
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• 2020

A numerical study was carried out to evaluate the aerodynamic characteristics of the supersonic grid fins installed on SpaceX Falcon 9. The unit-grid-fin concept was utilized for more efficient and simpler 3-D steady flow calculations. Pre- and post-correction processes that accounted the interference effects by the angle of attack of the missile, the influences of the outer frame of the grid fin and the connecting rods were improved in the study, and it was demonstrated that the present correction method was more accurate as compared to previous studies. Finally, the present approach was applied to evaluate the aerodynamic characteristics in transonic/supersonic flights of SpaceX Falcon 9 with various angle of attacks.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.570-578
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• 1997

At design stage of new motor or when taking remedial action of old motor, a lot of information can be obtained from thermal parameters analysis. This study focused on the temperature rise of TEFC induction motor with respect to various thermal parameters. Frame heat transfer had the most important effect on coil temperature rise. But those of air gap and rotor fan had no effect. This fact shows fan action is more important than fin action in the case of rotor fan. Coil temperature can be more decreased by cooling near the heat sources than any other parts from the results of thermal conductivity and loss tests. Variation of cooling air flow rate and motor volume effects on coil temperature were also tested. These tests suggest that improvement of cooling fan performance is important in reducing the coil temperature rise. Thermal equivalent program was verified by comparison of some experimental results.

• Journal of Environmental Science International
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• v.12 no.4
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• pp.383-391
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• 2003

The purpose of this research explain the meaning of the environmental design principles and cultural landscape pattern(dualistic space organization) of the Hahoe(河回:winding river village) the Yangdong(良洞) traditional village. Village's space organizations based on Shamanism, fin-yang and Five elements principle, Feng-shui idea, social system and Confucian ideas. And it were accomplish curat landscape pattern(village:form+object=pattern) through the frame of settlement space. As a central persons of villages(the Hahoe $.$ the Yangdong) construction, Suhae(西厓) experienced tough Chunghyodang - Wonjichongsa - Ogyonchongsa - Pyongsansowon channel(忠孝堂 -遠志精舍 -玉端精含 -脣山書院) and Kyomam(謙 ) experienced tough Yangjindang - Binyeonchongsa - Kyomamchongsa - Hwachonsodang(養眞堂 - 賓淵精舍 - 謙庵f精舍 - 花川書堂) channel. Also Woojae(愚齋) experienced tough Suhbackdang - Khankachung - Dongkangsowon(書百堂 - 觀稼停 - 東江書院) and Hoejae(晦齋) experienced tough Moochumdang - Hyangdan - Oaksansowon(無添堂 - 香壇 - 玉山書院). It is space organization of themselves interact contrast and sequence principles with competition in good faith. And ecological art-space, that is, environmental spare organizations of traditional village has been reflected harmony between nature and artificiality, spatial rhythm and sequence, spatial hierarchy between upper classes and humble class, permeability space, asymmetrical balance, aesthetic space perception. The humble classes hold a ceremony Hahoe's Pyolsingut-Talnori(maskdance drama), Dangjae(堂祭:religious service) at the Dang(堂:shamanism spot) and Yangdong's Sohraesulnori, Hohminori. And the upper class hold a ceremony Hahoe's Julbulnori and Yangdong's Chungjanori connected with culture of confucianism. Specially, the cultural structure cf the village is evidence of a contrast between the upper class and the humble classes, time, method and location of ceremony(performance).

• Nuclear Engineering and Technology
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• v.46 no.3
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• pp.439-446
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• 2014

An amphibious inspection robot system (hereafter AIROS) is being developed to visually inspect the in-containment refueling storage water tank (hereafter IRWST) strainer in APR1400 instead of a human diver. Four IRWST strainers are located in the IRWST, which is filled with boric acid water. Each strainer has 108 sub-assembly strainer fin modules that should be inspected with the VT-3 method according to Reg. guide 1.82 and the operation manual. AIROS has 6 thrusters for submarine voyage and 4 legs for walking on the top of the strainer. An inverse kinematic algorithm was implemented in the robot controller for exact walking on the top of the IRWST strainer. The IRWST strainer has several top cross braces that are extruded on the top of the strainer, which can be obstacles of walking on the strainer, to maintain the frame of the strainer. Therefore, a robot leg should arrive at the position beside the top cross brace. For this reason, we used an image processing technique to find the top cross brace in the sole camera image. The sole camera image is processed to find the existence of the top cross brace using the cross edge detection algorithm in real time. A 5-DOF robot arm that has multiple camera modules for simultaneous inspection of both sides can penetrate narrow gaps. For intuitive presentation of inspection results and for management of inspection data, inspection images are stored in the control PC with camera angles and positions to synthesize and merge the images. The synthesized images are then mapped in a 3D CAD model of the IRWST strainer with the location information. An IRWST strainer mock-up was fabricated to teach the robot arm scanning and gaiting. It is important to arrive at the designated position for inserting the robot arm into all of the gaps. Exact position control without anchor under the water is not easy. Therefore, we designed the multi leg robot for the role of anchoring and positioning. Quadruped robot design of installing sole cameras was a new approach for the exact and stable position control on the IRWST strainer, unlike a traditional robot for underwater facility inspection. The developed robot will be practically used to enhance the efficiency and reliability of the inspection of nuclear power plant components.