• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.237-244
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• 2011

An experimental study was carried out to investigate the effect of the inclination angle on the nucleate pool boiling of saturated water at atmospheric pressure. We considered an annulus with a gap of 5 mm and a bottom opening. The inner tube of the annulus was heated, and the outer diameter and the length of the tube were 25.4 mm and 500 mm, respectively. The inclination angle was varied from horizontal to vertical. The results were compared to those for an annulus with a larger gap and a single tube. In the small-gap annulus, the effect of the inclination angle on the heat transfer was not significant. However, an early onset of the critical heat flux was observed at 80 kW/$m^2$ when the annulus was horizontal. Liquid agitation and bubble coalescence were considered to be the major heat-transfer mechanisms.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.775-782
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• 2012

To investigate pool boiling heat transfer in a vertical annulus with closed bottoms, the length of an outer tube was varied between 0.3 and 0.6 m. For the test, a heated tube of 0.2-m length and 19.1-mm diameter and water at atmospheric pressure were used. To elucidate the effects of the outer tube length on heat transfer, the results for the annulus were compared with data for a single unrestricted tube. The increase in the outer tube length resulted in an increase or decrease in heat transfer depending on the gap size. This tendency is mainly attributed to the difference in the intensity of liquid agitation.

• Anatomy & Biological Anthropology
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• v.29 no.4
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• pp.145-154
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• 2016

The purpose of this study was to provide basic biometric data on Korean adults through magnetic resonance imaging (MRI)-based measurements of the distances between the apex of sacral hiatus (SH) and the termination of dural sac (DS), and between SH and conus medullaris (CM) because they are critical to the performance of epidural neuroplasty. A total of 200 patients(88 males and 112 females) with back pain, who had no spine fracture, significant spinal deformity, and spondyloisthesis were selected for this study. The subjects were of mean age 54.3 (20~84) years and mean height 161.3 cm (135~187). T2-weighted MRI images were used for correlation analysis to evaluate the relationships between the distances, and variables such as sex and height. In all patients, the mean distance between SH and DS was $62.8{\pm}9.4mm$ and the mean distance between SH and CM was $232.2{\pm}21.8mm$. The minimum distance and the maximum distance between SH and DS were 34.8 mm and 93.9 mm respectively, and the minimum distance and the maximum distance between SH and CM were 155.0 mm and 284.0 mm respectively. In female patients, both the distances between the SH and DS, and between SH and CM were shorter when compared to those of the male patients(p<0.05). Both the distances between SH and DS and between SH and CM showed a significant correlation with height(p<0.01). The results of this study will provide a useful biometric data on the distances between SH and DS and between SH and CM in Korean in ensuring clinical safety and in the development of more effective catheterization techniques for epidural neuroplasty in Korean.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.431-434
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• 2013

국민관광객과 방한 외래관광객의 증가(문체부, 2012)로 도서와 해안지역에 대한 관광수요가 확산됨에 따라 중앙정부와 지방정부는 등대(예 : 영도등대, 간절곶등대, 울기등대, 거문도등대)를 중심으로 국민생활속의 해양관광공간, 해양레저스포츠공간, 어촌체험공간, 유통관광중심의 어항개발 및 크루즈관광활성화를 위하여 노력하고 있다. 새로움을 추구하는 관광객의 욕구가 증가하면서 틈새관광(niche tourism)의한 형태로 도서 관광(small island tourism)이 주목되고 있다(김영준, 2011). 내륙 중심의 관광에서 해양 관광으로 관심이 변화 확산되면서 친수공간시설에 대한 관광수요의 증가가 예상된다(이한석, 심미숙, 2009). 이와 같은 현실에서 도서에 위치하고 있는 등대자원을 활용하여 관광객의 욕구를 충족시킬 수 있는 등대관광활성화가 기대된다. 등대가 전통적인 기능과 역할에 충실한 항로표지로서 뿐만 아니라 공공서비스장소로서 해양문화를 향유할 수 있는 체험의 장을 제공하고 건축문화유산으로서의 역사성과 등대 고유의 기능에 대한 관광객의 흥미와 욕구를 잘 접목시켜 해양관광자원으로서의 가치를 극대화할 수 있을 것이다.

• Archives of design research
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• v.19 no.4 s.66
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• pp.205-208
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• 2006

This work is a interactive digital art work which used the multiplex of jitter. It is an work which used a cross concept of two images. This work shows two kinds of images. One is on the wall through the gap of fluorescent lamp screen, and the other is on the fluorescent lamp screen. Two images are intercepted and comes out to the length as the multiplex of the jitter. The appearance of the spectator be recognized on the fluorescent lamp screen or on the wall, by two branch image which comes out intersecting of a length with multiplex function of the jitter. Two branch features of the image which it produces and the spectator which is input at real-time is equally divided, or in impression of juxtaposition goes in the spectator. It expresses the duplicity of the human being, with physical existence space divides the time space which we feel and there is a governing grammar which is different with each other and to express the thing it becomes. It used the image of the screen which it produces with the fluorescent lamp and cross concept.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.177-185
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• 2009

The failure analysis of scales deposited on automotive thermostat housing has been carried out. Observations using energy dispersive spectroscopy and electron probe micro analyzer indicate that the main components of scales are some of additives of coolant used. For a detailed investigation of organic matters pyrolysis-GC/MS is employed. The result shows that the main organic component is benzoic acid and furthermore, a small amount of acetophenone, benzene and phenyl group is detected. Based on the results of failure analysis performed, the scales on automotive thermostat housing appear due to the deposition of coolant components, followed by crevice corrosion, into gap between housing and rubber horse. New accelerated test methodology, which could mimic the scale formation and the crevice corrosion on thermostat housing, is developed considering the above results. In order to reproduce the real operating conditions, the accelerating factors, i.e. temperature and humidity, are changed and programmed. The reproducibility of the accelerated test proposed is confirmed after analyzing the scales obtained from the accelerated test.

• Nuclear Engineering and Technology
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• v.24 no.3
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• pp.228-235
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• 1992

Some soluble species may not be solubility-limited or congruent-released with the matrix species. For example, during the operation of the nuclear reactor, the fission products can be accumulated in the fuel-cladding gap, voids, and grain boundaries of the fuel rods. In the waste package for spent-fuel placed in a geologic repository, the high solubility species of these fission products accumulated in the“gap”, e.g. cesium or iodine are expected to dissolve rapidly when ground water penetrates fuel rods. The time and space dependent mass transport for high solubility nuclides in the gap is analyzed, and its numerical illustrations are demonstrated. The approximate solution that is valid for all times is developed, and validated by comparison with an asymptotic solution and the solution obtained by the numerical inversion of Laplace transform covering the entire time span.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1023-1037
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• 2018

The interest in the use of shield TBM (Tunnel Boring Machine) on the tunnel excavation has been increased rapidly in Korea. The shield TBM tunnel is generally designed as non-drainage tunnel. Consequently, if water leakage through the segment joints happens, big problems on the usage and stability of tunnel can be occurred. In this study, the variation of waterproof capacity of hydrophilic rubber waterstop and gasket, respectively by the construction error and excessive displacement of segment was studied. The test results show that hydrophilic rubber waterstop has favorable on the offset, however unfavorable on the gap. On the other hand, gasket has unfavorable on the offset, however favorable on the gap.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.285-292
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• 1999

The design parameter of the reactor vessel insulation for the Korea Standard Power Plant has been studied numerically. The heat loss from the reactor vessel through the insulation is analysed by using the computational fluid dynamics code, FLUENT. Parametric study has been performed on the air gap width between the reactor vessel wall and the inner surface of the insulation, and on the insulation thickness. Also evaluated is the performance degradation due to the chimney effect caused by gaps between the panels during the installation of the insulation system. From the analysis results, the optimal air gap width and the optimal insulation thickness are obtained.

• Journal of the Korea Institute of Building Construction
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• v.22 no.3
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• pp.239-249
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• 2022

Fire resistance performance and performance design of fire doors are becoming more important to prevent the spread of fire and support the rapid evacuation of apartment buildings. In this study, a database using 182 evacuation spaces and 308 common areas that passed the fire performance test was established, and fire door performance influencing factors were derived through an analysis of the structure(12 elements) of the fire door. As a result, the effects of fire-resisting filler density, adhesive, and foam gasket were confirmed for evacuation space, and the effects of fire-resisting filler, adhesive, and fire fins were confirmed for common areas. In the fire door fire resistance test, flames and cracks were analyzed as the most frequent failure factors.