• 한국화재소방학회논문지
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• 제32권1호
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• pp.24-32
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• 2018

수리계산방식에 의한 설계는 전산프로그램을 사용하는 방식과 직접 설계자가 계산에 의하여 설계하는 방식이 있다. 전산프로그램을 사용하는 경우 필요한 조건을 입력하면 프로그램에 의해 마찰손실, 유량, 양정 등을 계산하여 주지만 기본적인 개념과 절차를 모르게 되면 계산값이 입력자마다 다를 수가 있어 절차상의 기준을 정하는 것이 필요하다. 설계자가 직접 계산하는 경우에도 동일하다. 따라서 설계면적 내에서 수리계산의 절차를 다음과 같이 제시하였다. 가지관에 설치되는 티의 등가길이는 방출구(Outlet)의 관경이 다를지라도 설치된 배관의 관경과 동일한 관경(Run)의 등가길이를 선택한다. 가지관 중간에 손실값이 큰 다른 헤드가 있더라도 말단에서부터 계산해온 압력이 더 크다면 말단헤드에서부터 계산해온 압력으로 헤드방출량을 계산한다.

• 한국작물학회지
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• 제38권6호
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• pp.554-559
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• 1993

냉수관개가 벼 생육특성, 수량 및 미질관련 형질에 미치는 영향을 검토하기 위하여 작물시험장 춘천출장소 냉수처리포장에서 실시한 시험 결과를 요약하면 다음과 같다. 1. 냉수구에서는 자연구에 비하여 출수가 10～19일 지연되었고 간장과 수장은 17～31% 단축되었다. 수수는 일정한 경향이 없으며 품종간에 반응이 상리하였다. 2. 냉수구에서 영화수는 이삭당 10～35개가 감소되었고 등숙률이 현저히 떨어졌으며, 정조수량은 오대벼 치악벼등이 높은 수량을 나타낸 반면에 백암벼 소백벼 진미벼등은 낮은 수량을 보였다. 고중은 공시품종 모두 냉수구에서 높았다. 3. 현미 완전미율은 냉수구와 자연구간에 일정한 차이가 없었고 오히려 품종간의 변이가 크게 나타났고, 청미율은 자연구에서 많은 경향이며 연색미는 냉수구에서 월등히 높았다. 4. 백미 투명도및 알칼리 붕괴도는 수구쪽에서 높은 경향이며, 아밀로스 함량은 자연구에서 높았다.

• International Journal of Human Ecology
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• 제8권2호
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• pp.29-46
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• 2007

The purpose of this study was to analyze characteristics of the bedroom environment of nursing homes for the elderly in Korea. Field case research was performed using a structured checklist and measurements, from Oct. 28th to Dec. 2nd, 2006. Collected data were analyzed for cognitive efficiency, privacy, safety, supportiveness and amenity. Based on nursing homes for the elderly nationwide (Ministry of Health and Welfare, 2006), we choose 43 facilities in which Seoul and six megalopolis areas that had answered our questionnaire in 2006. We then narrowed the list to 14 facilities, balanced them in terms of regional population. The contents of investigation consisted of eight categories: that general characteristics of the bedrooms (including number of residents per room, using a bed or floor mat, the size and shape of the chamber, space for wheelchair turning, signage), door of bedroom (including door, doorknob, door sill/level difference), windows in the bedroom(including type of window, window sill height, window treatment, window safety device/shape, view/daylight), furniture (including personal furniture and lock), finishes (material, character and color of wall, floor, ceiling), lighting (including types of lighting, night lighting, switch), bathroom in the bedroom (including signage, door size/type, doorknob shape, height of the washbowl, size of toilet bowl, handrail, finishes), and other facilities (including outlet and handrails).

• 대한기계학회논문집B
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• 제36권1호
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• pp.1-8
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• 2012

본 연구에서는 주름높이가 고려된 판형열교환기의 완전발달유동 및 열전달특성을 수치적으로 해석하였다. 여러 개의 단위셀(5개 또는 7개)을 연결한 다중셀에 입구부와 출구부가 부착된 모델을 기본으로 P/H비 변화($2.0{\leq}P/H{\leq}4.0$)에 따른 모델에 대하여 수치해석을 수행하였다. 작동유체는 물이며, 수치조건은 쉐브론각 $20^{\circ}$, $300{\leq}Re{\leq}1,500$이다. 그리고 마찰인자는 $f=CRe^m$의 형태로, Colburn 계수는 $j=CRe^m$의 형태로 상관관계식을 제시하였다. 수치해석 결과 완전발달유동은 세 번째 셀부터 시작되었으며, 누셀트수는 P/H비가 작을수록 큰 값을 나타냈다.

• 한국태양에너지학회 논문집
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• 제39권6호
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• pp.83-91
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• 2019

Photovoltaic thermal (PVT) collectors are devices that simultaneously produce electricity and heat. Research on conventional air-type PVT collector focuses on installing baffles to enhance the collector's thermal performance. However, the baffles have pressure drop inside the collector which degrades the thermal performance. Thus, it is necessary to design baffles to smoothen the flow inside the air-type PVT collector. Alternatively, installing perforated baffles in air-type PVT collectors can reduce the collector weight, but parameters such as the diameter of the perforated holes and the height of the perforated plates should be considered. Therefore, the main aim of this study was to analyze thermal characteristics of each variable of perforated baffles installed inside air-type PVT collector. For this purpose, the uniformity of air flow in the collector was compared through NX program, and the resultant heat gain and thermal efficiency of the air-type PVT collector were compared and analyzed. Therefore, the main aim of this study was to analyze thermal characteristics of each variable (Baffle angle, length, height, pitch, perforated ratio) of perforated baffles installed inside air-type PVT collector. For this purpose, the uniformity of air flow in the collector was compared through CFD program, and the resultant heat gain and thermal efficiency of the air-type PVT collector were compared and analyzed. As a result, the maximum outlet temperature was increased by 1.45 times and the heat gain was increased by 193.8 Wth, depending on the perforated baffle plate, compared to the collector without the baffle. The heat transfer performance showed that the maximum internal velocity was 1.61 times higher and the Reynolds number was 1.06 times higher depending on the parameters of the baffle plate.

• 대한기계학회논문집B
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• 제26권6호
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• pp.883-892
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• 2002

A numerical study has been carried out to investigate the flow and heat transfer from an aluminum foam heat sink in a confined channel. A uniform heat flux is given at the bottom of the aluminum foam heat sink, which is horizontally placed on the heated surface. The channel walls are assumed to be adiabatic. Cold air is supplied from the top opening of the channel and exhausted to the channel outlet. Comprehensive numerical solutions are acquired to the governing Wavier-Stokes and energy equations, using the Brinkman-Forchheimer extended Darcy model and the local thermal non-equilibrium model f3r the region of porous media. Details of flow and thermal fields are examined over wide ranges of the principal parameters; i.e., the Reynolds number Re, the height of heat sink h/H, porosity $\varepsilon$and pore diameter ratio $R_{H}$.

• 한국농공학회논문집
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• 제47권7호
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• pp.57-66
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• 2005

The Hydrological Simulation Program - FORTRAN (HSPF) was modified to simulate nonpoint pollutant loadings from paddy fields using a field experimental data collected during 2001-2002. The concept of a 'dike height' was added in a modified HSPF code, named HSPF-Paddy, to consider the function of retaining water by a weir at the field outlet. The effect of fertilization on the variances of nutrients on the soil surface and shallow soil layer was described mathematically with a Dirac delta function (or first-order kinetics). As confirmed through model verification, the HSPF-Paddy modifications were shown to represent the function of retaining water, varied ponded water, and surface runoff by forced drain during both rainy and non-rainy seasons and reasonably predicted the water balance and nutrients behavior in paddy fields. It is a distributed watershed model which, with the paddy modifications, can now simulate nonpoint pollutant loadings where paddy fields are dominant, and it can be used to evaluate the effects of paddy fields on the water quality at a basin scale, and assess the impacts of proposed BMPs applied to paddy fields.

• 동력기계공학회지
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• 제19권5호
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• pp.32-37
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• 2015

The present study is to investigates the convective heat transfer characteristics and pressure drop inside the rib-roughened cooling passage of gas turbine blades. The divergent rectangular channel is fabricated with V-shaped ribs on one wall only and the inlet hydraulic diameter to outlet hydraulic diameter ratio($D_{ho}/D_{hi}$) of 1.49 is used. The current investigation has covered a Reynolds number (Re) range of 22,000~75,000, relative roughness height ($e/D_h$) of 0.1~0.2, and rib angle of attack (a) of $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$ for a fixed relative pitch of 10. Results show that the Nusselt numbers are the greatest in the $60^{\circ}$-angled ribs; however, the total friction factors are the highest in the $30^{\circ}$-angled ribs.

• 설비공학논문집
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• 제26권9호
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• pp.416-423
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• 2014

To verify different boundary conditions on the borehole wall, which are commonly used for generating g-function, the well-known TRNSYS simulation model, DST (Duct STorage), is employed. By letting the fluid circulation determine the borehole wall conditions, a DST-based g-function is induced with numerical processes proposed in this work. A new TRNSYS module is also developed to accommodate g-function data and predict dynamic outlet fluid temperatures. Results showed that the modified g-function, which is different from Eskilson's original g-function, is closer to the DST-based g-function. This implies that the uniform heat transfer rates over the height can be used for good approximation. In fact, simulations with the modified g-function showed similar results as the DST model, while Eskilson g-function case deviated from the DST model as time progressed.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.234-238
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• 2008

The energy conservation theory is introduced for investigating processes of runoff and soil erosion on the hillslope system changed vegetation condition by wildfire The rainfall energy, input energy consisted of kinetic and potential energy, is influenced by vegetation coverage and height. Output energy at the outlet of hillslope is decided as the kinetic energy of runoff and erosion soil, and mechanical work according to moving water and soil is influenced dominantly by the work rather than the kinetic energy. Relationship between output and input energy is possible to calculate the energy loss in the runoff and erosion process. The absolute value of the energy loss is controlled by the input energy size of rainfall because energy losses of runoff increase as many rainfall pass through the hillslope system. The energy coefficient which is dimensionless is defined as the ratio of input energy of rainfall to output energy of runoff water and erosion soil such as runoff coefficient. The energy coefficient and runoff coefficient showed the highest correlation coefficient with the vegetation coverage. Maximum energy coefficient is about 0.5 in the hillslope system. The energy theory for output energy of runoff and soil erosion is presented by the energy coefficient theory associated with vegetation factor. Also runoff and erosion soil resulting output energy have the relation of power function and the rates of these increase with rainfall.