• 대한기계학회논문집
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• 제5권4호
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• pp.284-292
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• 1981

The flow of fluid with low prandtl number in the entrance region of a circular pipe has been considered, where the wall temperature is maintained to be constant. A finite difference method is used for the integral form of the governing equations in order that they satisfy the conservative properties of the numerical solutions. It is confirmed that the hydrodynamic entrance length and be divided into growing boundary layer region and fully viscous region, which is compared with existing results obtained by using boundary layer approximations. By assuning the developing velocity profile in the entrance region, the thermal entrance length is estimated and the local Nusselt number is obtained at various locations along the axial dirction.

• 수산해양기술연구
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• 제52권1호
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• pp.9-16
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• 2016

This study was conducted to analyze fishing capacity and bycatch by mesh size and entrance size of spring net pot conducted by water tank and field experiment. The water tank experiments were conducted by using traps with mesh size of 22 mm and entrance size of 120 mm and 140 mm, respectively in the water tank of NIFS. The field experiment was conducted using 5 kinds of spring net pot with mesh sizes of 20 mm, 22 mm, 35 mm and entrance size of 120 mm, 130 mm, 140 mm, 360 mm by coastal trap fishery vessel operating around the area of Geoje island. In the result of water tank experiments, the catch of conger eel was 1.5 times higher when using trap with entrance size of 140 mm than that of 120 mm. In the field experiment, when using same mesh size, the larger the entrance size, the higher amount of conger eel catch, bycatch and number of bycatch species. When using the same entrance size, the larger the mesh size, the lower amount of conger eel catch and number of bycatch species, whereas the amount of bycatch showed increasing trend.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.862-870
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• 1998

In this paper an experimental investigation of characteristics of developing transitional unsteady flows in a square-sectional 180。 curved duct are presented. The experimental study using air is carried out to measure axial velocity profiles secondary flow velocity profiles and entrance length by using Laser Do ppler Velocimeter(LDV) system. The flow development is found to depend upon Dean number dimensionless angular frequency velocity amplitude ration and cur-vature ratio. Of special interest is the secondary flow generated by centrifugal effects in the plane of the cross-section of the duct. The secondary flows are strong and complicate at entrance region. The entrance length of transitional pulsating flow is obtained to 120。 of bended angle of duct in this experimental conditions.

• 한국화재소방학회논문지
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• 제5권2호
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• pp.21-35
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• 1991

As a part of studies of drag reduction phenomenon, at the entrance flow region of abrupt contraction tube flowing water, dilute and concentrated drag reducing polymer solutions contraction losses are estimated experimentally. Futher more, entrance lengths are considered theoretically and are measured experimentally. In the present experiment, fluid temperature is fixed l$0^{\circ}C$ and flow rates are 3,000

• Journal of Advanced Marine Engineering and Technology
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• 제23권1호
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• pp.33-39
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• 1999

In this paper an experimenatal investigation of characteristics of developing ransitional steady flows in a square-sectional $180^{\circ}$ curved duct is presented, The experimental study is carried out to measure axial velocity profiles secondary flow velocity profiles and entrance length by using Laser Dopper Velocimeter(LDV) system. The flow development is found to depend upon Dean number and curvature ratio. Of special interest is the secondary flow generated by centrifugal effects in the plane of the cross-section of the duct. The secondary flows becomes strong from $120^{\circ}$ of bended angle on the duct. The entrance length of transitional steady flow is obtained to $120^{\circ}$ of bended angle of the duct in this experimental conditions.

• Journal of the Korean Data and Information Science Society
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• 제21권3호
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• pp.523-534
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• 2010

본 연구의 목적은 이중 이동평균법에 의한 초, 중, 고등학교 학생 수 예측 기법을 이용하여 2027년까지의 수도권의 고3학생 수를 예측하고, 수도권 전문대학, 대학교 입학정원과 대학과 전문대학, 교육대학을 합한 총 입학정원과의 관계를 향후 2027년까지 분석하는 것이다. 이 분석 결과 수도권의 집중화 현상으로 심각한 저 출산의 영향에도 불구하고, 수도권의 대학들의 신입생 유치에는 문제가 없다. 그러나 향후 대학들의 입학정책에 영향을 끼칠 것이다.

• 대한기계학회논문집
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• 제13권5호
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• pp.1032-1043
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• 1989

본 연구에서는 해석적으로 열적 입구 길이를 규명하는데 필요한 와류 열확산 계수를 실험 결과를 이용하여 결정하고, 시험관 입구의 형상 변화가 열전달 특성에 미치는 영향을 실험적으로 결정하며, 열적 입구 길이 영역에서 국소 열전달 계수를 표시할 수 있는 실험식을 제시하고, 유체의 전단율에 따른 점성 계수의 실험 결과와 점탄성 유체의 특성시간을 이용한 새로운 무차원 수인 Weissenberg수를 결정하여 퇴화 현상을 분석하고저 한다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.129-130
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• 2019

In this research, we determine the proper number of entrances in the evacuation facilities for civil and military personnel. The current standards on the emergency evacuation facility only sets the number of possible evacuees and the according architectural floor area since the evacuation have been completed. However, other than static standards such as the floor area, there is needs to consider the dynamic standards along with allowable evacuation time such as the number of entrance, staircases and so on. Therefore, we need to consider the number of entrances and their location in order to account for the allowed evacuation time of particular number of people in a set area. The outcome could be contributed to the standards which should contain the dynamic conditions associated with evacuation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1485-1490
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• 2003

This paper is the analysis of thermal and fluid in solar concentration absorber with various tilt angle and opening ratio of absorber entrance. The purpose of this study is to develop optimum solar concentration absorber, and the parameters for the study are the opening ratio of absorber entrance and the tilt angle. The aspect ratio of absorber was fixed at 0.64, and opening ratio was changed from 0.1 to 1.0. The finite volume method with SIMPLE computational algorithm are used and analyzed the heat transfer in absorber inside walls.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제29권1호
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• pp.7-19
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• 2023

Purpose: Mobility impairment persons are all people who experience mobility difficulties in their daily lives, which makes up about 30% of the population in Seoul Metropolitan City; this number is expected to increase with population aging. As the number of mobility impairment persons in need of vision correction increases, it is necessary to create the Universal Design guidelines and to provide the foundation to access convenience facilities at the entrance of optical shops, a health and medical institution. Methods: Of the 2,282 optical shops located in Seoul, 252 optical shops were chosen for data collection of actual photos, from April 10, 2022 to September 4, 2022. Based on the photographs, the height difference between the entrance and the sidewalk, safety handles, and opening and closing methods of entrances were investigated, as these factors correspond to the accessibility and the mobility of the mobility impairment persons. Results: Of the 252 optical shops surveyed, 114 (45.2%) have resolved the problems of height difference through improving horizontal accessibility (61) or using ramps (53). 36 (14.3%) optical shops chose automatic doors for opening and closing methods of the entrance. Implications: The rate of installation of access convenience facilities for the entrance of optical shops is slightly lower than the rate of installation of ramps, surveyed by the Ministry of Health and Welfare. It is necessary to apply the Universal Design to access convenience facilities for the entrance of optical shops for not only the mobility impairment persons but all people, regardless of age or ability, to conveniently access healthcare services.