• Solar Energy
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• v.12 no.1
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• pp.48-58
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• 1992

In the present investigation, experimental analysis was performed to research heat transfer phenomena generated by means of conduction and natural convection at a succession of tube-inclimations relative to the vertical tube during inward melting process of a phase change material. The phase change material used in the experiments is 99 percent pure n-docosane paraffin($C_{22}H_{46}$). When the tube is vertical, the dominant mode of energy transfer between the tube wall and the melting interface is natural convection. On the other hand, when the tube is inclined to the vertical, the melting solid is brought into direct contact with the tube wall by the action of gravity. In the experimental results, direct contact gave rise to substantial enhancements in the amount of melted mass, relative to those for natural-convection-dominated melting.

• The Korean Journal of Rheology
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• v.4 no.1
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• pp.25-34
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• 1992

저속으로 낙하하는 원통형 미소체의 유체역학적 거동에 대하여 점탄성 유체의 비 뉴우튼 성질의 영향에 관해서 연구가 수행되었다. 원통형 미소체의 직경 및 직경에 대한 길 이의 비 (Aspect Ratio)의 영향에 관해서도 또한 고찰하였으며 본 실험에서는 뉴우튼 유체 로서 99.5%의 글리세린용액과 점탄성 유체로서 1,000 wppm 의 polyacyla-mide(Separan AP-273) 수용액이 각각 사용되었다. 낙하하는 미소체의 Aspect Ratio가 증가할수록 무차원 최종속도는 뉴우튼 유체내에서 보다 점탄성 유체내에서 그증가속도가 더욱 커짐을 보였다. 뉴우튼 유체 내에서 낙하하는 원통형 미소체의 마찰저항 계수는 실험데이타로부터 계산된 값과 이론치가 비교적 잘일치하나 점탄성 유체에 관한 마찰저항 계수는 본 실험의 결과치와 무한히 긴 원통형 미소체에 대한 기존연구의 이론값과는 상당한 차이가 있음을 알수 있었 다, 이는 점탄성 유체내에서 수직으로 낙하하는 원통형 미소체의 저항계수가 k(즉 용기의 직경에 대한 미소체 직경의 비), power-law index 레이놀즈수 뿐아니라 aspect ratio를 포함 하는 새로운 관계식이 도출되어야 함을 분명히 보여주고 있다.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.31-36
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• 2008

The embryonic and postembryonic developments of Nezara antennata Scott were observed in 5 different rearing cages such as A (Cylindrical, ${\phi}\;10cm{\times}4cm$), B (Cylindrical, ${\phi}\;14.5cm{\times}2.8cm$), C (Rectangle, $6.5L{\times}6.5cmW{\times}10cmH$), D (Cylindrical, ${\phi}$ 9cm in bottom & ${\phi}$ 11.5 cm in $upper{\times}10.8cm$) and E (Cylindrical, ${\phi}\;15cm{\times}7.5cm$) containing soybean and peanut seeds as food, and sponge soaked with water under laboratory condition of $24^{\circ}C$ and 15L : 9D. Hatchability ranged from 93 to 97%. Nymphal duration was shortest of 6 days in the 1st instar and longest of 10 days in the 5th instar. The nymphal duration was 38 to 39 days observed in the rearing cages. Emergence rate was in the range from 53 to 62% with highest in A and B cages. Adult longevity was 65 to 75 days for male, and 67 to 74 days for female, and was longest in the B cage. Total number of eggs laid by female adult was in the range from 51 to 56 without significant difference in the rearing cages, and was the most in the B cage. Accordingly, the reproductive rate of N. antennata for 1 generation was within 25 to 33 times, and was highest in the B rearing cage. Therefore, it could be concluded that B cage is most suitable for stable rearing of N. antennata under laboratory condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.108-115
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• 2016

In this paper, fluid-structure of interaction behavior of a fluid-filled cylindrical polymer container impacted by a high speed spherical projectile was studied using ALE(Arbitrary Lagrangian Eulerian) method. The hydrodynamic ram phenomenon occurred by the impact projectile penetrating through the container was investigated by examining time histories of projectile velocity and fluid pressure and density. The analysis results were agreed reasonably well compared to those by experiments.

• Science of Emotion and Sensibility
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• v.19 no.2
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• pp.19-26
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• 2016

Previous research has shown that people perceive the larger volume for tall and lean cylindrical containers over short and wide containers of the same volume (e.g., Raghubir & Krishna, 1999; Wansink & Van Ittersum, 2003). The present research demonstrated that this elongation effect is reversed for boxes, presumably due to the affordance of the boxes. Two studies showed that participants judge short and wide boxes as having larger volume than long and lean boxes of the same volume. This effect replicated through two types of presentation formats (drawing, Study1; actual object, Study2) when the choice between two boxes was forced (Study 1) and not (Study 2). The results also replicated among participants residing in the U.S. (Study 1) and participants residing in Korea (Study 2). The reversed elongation effect held for liquid materials in general (water, Study 1; drinks, Study 2). Theoretical and managerial implications are discussed.

• Nuclear industry
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• v.23 no.3 s.241
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• pp.42-48
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• 2003

가압 경수로는 원통형의 원자로 용기 안에서 핵물질을 반응시켜 고온$\cdot$고압의 물을 생성하는데 이 원자로 용기는 환형 주조물들을 서로 용접하여 만들어진다. 이 원자로 용기의 건전성을 확인하기 위해서는 용접부위에 결함이 발생되었는지를 주기적으로 정확하게 검사해야 한다. 한국원자력연구소는 원자력발전소의 핵심 기기인 원자로 용기의 용접부 결함을 수중에서 자동으로 검사, 탐지할 수 있는 $\ulcorner$원자로 자동 탐상 시스템$\lrcorner$을 개발하여, 울진 원전 6호기용 원자로 용기에서 실증 실험을 수행하였다. 이 원자로 자동 탐상 시스템은 물방개처럼 생긴 수중 탐상 로봇이 그 핵심으로서 이 로봇은 원자로 용기의 내벽을 타고 다니면서 수중 초음파 검사를 수행할 수 있는 획기적인 시스템이다. 본고에서는 개발된 원자로 자동 탐상 시스템을 소개하고자 한다.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.293-298
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• 2005

The embryonic and postembryonic developments of Pierodorus hybneri Linnaeus were observed in 5 different rearing cages such as A (Cylindrical, 10 cm in diameter, height of 4 cm), B (Cylindrical, 14.5 cm in diameter, height of 2.8 cm), C (Rectangle, 6.5 by 6.5 cm in $length{\times}breadth$, height of 10 cm), D (Cylindrical, 9 cm in bottom diameter, 11.5 cm in upper diameter, height of 10.8 cm) and E (Cylindrical, 15 cm in diameter, height of 7.5 cm) containing soybean and peanut seeds as feeding food, and sponge-water container under laboratory condition of $24^{\circ}C$ and 16L:8D. Egg duration was 6 days regardless of rearing cages. Hatchability ranged from 63 to 80% with the highest in B (14.5 cm in diameter, 2.8 cm in height) rearing cage. Instar duration was longer from 5 days in 1st instar to about 11 days in 5th instar. Nymphal duration showed 35 to 36 days with'3ut significant difference in rearing cages. Percent emergence was in range from 65 to 82% with the highest in B rearing cage. Adult longevity was 35 to 83 days for male, and 32 to 79 days for female, and was the longest in B rearing cage. Total number of eggs laid by female adult was in range from 38 to 86 with significant difference in rearing cages, and was the most in B rearing cage. Accordingly, the reproductive rate of P. hybneri for 1 generation was within 17 to 56 times, and was the highest in B rearing cage. Therefore, it could be concluded that B cage is most suitable for stable rearing of P. hybneri under laboratory condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.12
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• pp.1043-1050
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• 2014

An air-core vortex is generated during draining after stirring a rotating cylindrical tank or after filling it with water. The formation of the air-core vortex and the time of its formation are dependent on drain conditions such as the dimensions of the tank, the initial rotation or stirring speed, and the shape of the drain port. In this study, a draining process using a two-stage drain port was numerically investigated. The length and radius of the first drain stage located in the lower part of the drain port were kept constant, whereas the radius of the second drain stage was varied for simulating the draining process. The simulation was conducted by considering an axisymmetric swirling flow for all cases. The declining water level was monitored by an interface capturing method. Further, the effects of the radius of the second drain stage on the time of formation of the air-core vortex and the internal flow structure were investigated.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.51-58
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• 2001

In the low level radioactivity measurement, such as environmental radioactivity, there were used commonly cylindrical and Marinelli type beakers by means of measurement container. If there are differences in the matrix density or sample height between standard source and sample, it must be determined full energy peak efficiency considering self absorption effect. In this paper, we compared measured efficiency with calculated full energy peak efficiencies in the HPGe detector using the Monte Carlo method. For cylindrical container, we calculated the variation of the efficiency with sample height. Also, we calculated the variation of the detection efficiency with apparent density in the cylindrical and Marinelli container. It was seen that it need to be corrected for self absorption in the energy range of below 1000keV. Also, in order to verify the validity of calculation, we compared the calculated value with reference value using NIST SRM 4353 reference soil.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1627-1633
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• 2012

A deep-sea pressure vessel needs to protect the internal electrical equipment from the high external pressure. Thus, the pressure vessel should be designed to be watertight and structurally safe. In this study, a cylindrical-type pressure vessel comprising a hollow cylinder and cover plates at both ends is investigated. For communication between the internal electronic equipment and the external device, holes are bored on the cover plate to install underwater connectors. Considering the type of internal equipment and underwater connector specifications, multiple holes may be required. These holes can affect the structural safety of the pressure vessel cover plate. In this study, the optimum design of the hole arrangement in consideration of the structural safety of the cover plate was performed.