• Title/Summary/Keyword: Coefficient of utilization

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A Study on the Field Survey on the Usage Pattern of Church-affiliated Kindergarten (교회 부설 유치원의 이용실태 조사 연구 - 전북 전주시·익산시를 중심으로 -)

  • Lee, Moon Chul;Lee, Dong Suk;Yoon, Choong Yeul
    • Journal of the Korean Institute of Rural Architecture
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    • v.7 no.1
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    • pp.100-111
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    • 2005
  • Recent architecture of church purport to develop churches that are open towards regional society, and volunteer programs are executed to benefit diverse regional societies. As a means of various programs, church-affiliated of kindergarten which is social welfare facility is installed. Through church-affiliated of kindergarten, the awareness that it does not merely benefit and satisfy the needs of regional residents. Accordingly, diverse forms and structures are emerging within the protestant church both in terms of education and construction. Accordingly, this research conducted by focusing on church-affiliated of kindergarten. The results are summarized as follows.

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SORET AND DUFOUR EFFECTS ON RADIATIVE HYDROMAGNETIC FLOW OF A CHEMICALLY REACTING FLUID OVER AN EXPONENTIALLY ACCELERATED INCLINED POROUS PLATE IN PRESENCE OF HEAT ABSORPTION AND VISCOUS DISSIPATION

  • VENKATESWARLU, M.;BHASKAR, P.;LAKSHMI, D. VENKATA
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.23 no.3
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    • pp.157-178
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    • 2019
  • The present correspondence is conveyed on to consider the fascinating and novel characteristics of radiative hydromagnetic convective flow of a chemically reacting fluid over an exponentially accelerated inclined porous plate. Exact solutions for the fluid velocity, temperature and species concentration, under Boussinesq approximation, are obtained in closed form by the two term perturbation technique. The interesting parts of thermal dispersing outcomes are accounted in this correspondence. Graphical evaluation is appeared to depict the trademark direct of introduced parameters on non dimensional velocity, temperature and concentration profiles. Also, the numerical assortment for skin friction coefficient, Nusselt number and Sherwood number is examined through tables. The certification of current examination is confirmed by making an examination with past revelations available in composing, which sets a benchmark for utilization of computational approach.

A Study on Transport and Heat Utilization of Ice Slurries (아이스 슬러리의 수송 및 냉열이용에 관한 연구)

  • 길복임;이윤표;정동주;조봉현;최은수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.11
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    • pp.1065-1071
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    • 2001
  • To investigate hydraulic and thermal characteristics of ice slurries in a circular tube, ice slurries were tested in a flow loop with a constant heat flux test section, for ranges of flow velocity, ice fraction and heat flux. Heat transfer coefficients and friction factors of ice slurries were calculated by measuring the outer wall temperatures of the test section and the pressure drops over the test section. Heat transfer coefficients of ice slurries were 9% higher than the heat transfer coefficients expected by Petukhov. Friction factors were about 4% lower than the friction factors expected by Petukhov. The effective thermal capacity of ice slurry with 12.8% ice fraction, was found to be about 3 times higher than the thermal capacity of water.

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Characteristics of the Stored and Released Thermal Energy in Plastic Greenhouse with Underground Heat Exchange System (지중열교환(地中熱交換) 온실(溫室)의 축열(蓄熱) 및 방열(放熱) 특성(特性))

  • Lee, C.H.;Park, S.J.;Kim, Y.H.;Kim, C.S.;Rhee, J.Y.
    • Journal of Biosystems Engineering
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    • v.19 no.3
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    • pp.222-231
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    • 1994
  • The efficient use of solar energy for greenhouse heating is one of the most obvious applications to save the heating energy for greenhouse culture. To increase the efficiency of solar energy utilization in plastic greenhouse, underground heat exchange system was installed. Characteristics of the stored and released thermal enery in plastic greenhouse with underground heat exchange system was analyzed. The average stored and released thermal energy in this system were 1,484 $kJ/m^2$ day and 555 $kJ/m^2$ day, respectively. The average coefficient of performance of heat exchange system was found to be 2.86. Also an attempt was made to predict the air temperature in plastic greenhouse. The agreement between the results of prediction and that of measurement was relatively good.

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Thermal Influence on Hydraulic Conductivity in Compacted Bentonite: Predictive Modeling Based on the Dry Density-Hydraulic Conductivity Relationship

  • Gi-Jun Lee;Seok Yoon;Won-Jin Cho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.22 no.1
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    • pp.17-25
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    • 2024
  • Hydraulic conductivity is a critical design parameter for buffers in high-level radioactive waste repositories. Most employed prediction models for hydraulic conductivity are limited to various types of bentonites, the main material of the buffer, and the associated temperature conditions. This study proposes the utilization of a novel integrated prediction model. The model is derived through theoretical and regression analyses and is applied to all types of compacted bentonites when the relationship between hydraulic conductivity and dry density for each compacted bentonite is known. The proposed model incorporates parameters such as permeability ratio, dynamic viscosity, and temperature coefficient to enable accurate prediction of hydraulic conductivity with temperature. Based on the results obtained, the values are in good agreement with the measured values for the selected bentonites, demonstrating the effectiveness of the proposed model. These results contribute to the analysis of the hydraulic behavior of the buffer with temperature during periods of high-level radioactive waste deposition.

Design of Planar-Type Modified Folded Loop Antennas

  • Park, Sung-Il
    • Journal of information and communication convergence engineering
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    • v.8 no.5
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    • pp.489-492
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    • 2010
  • This paper proposes the planar-type modified monopole antennas of loop structure. This antenna has an opened center of a conventional closed loop structure with an inside-folded terminal of the loop microstrip line. The size of the proposed antenna was minimized by folding the end of the loop. Also, the reactance value has been minimized by increasing capacitances between the coupled microstrip line. Therefore the proposed antenna has been compacted to about 20% from a conventional loop antenna and has increased its efficiency. The proposed antennas have an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6~3.56 GHz) with VSWR$\leq$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9%. These properties could satisfy the S-DMB band.

Design of Planar Modified Folded Loop Antennas for S-DMB band (위성 DMB 대역을 위한 수정된 폴디드 루프 안테나)

  • Lee, Hyeon-Jin
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.61 no.1
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    • pp.1-4
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    • 2012
  • In this paper, the planar type modified folded loop antennas for S-DMB band is proposed. The proposed antenna consisted of opened center of a conventional closed loop and folded terminal of microstrip line to inside loop antenna. The sizes proposed antenna was minimized by folding the terminal of the loop. Also, It was minimized reactance value by increasing capacitances between coupled microstrip line. Therefore the proposed antennas compacted about 20% than a conventional loop antenna and increased efficiency of antenna. The proposed antennas got an omni-directional pattern, the antenna gain was 3.67 [dBi] and the bandwidth was 900 MHz (2.6-3.56 GHz) with VSWR${\leq}$2 from the simulated and the measured results. The frequency utilization coefficient was 29.9 %. These properties could satisfy the S-DMB band.

A Study on the Improved Winding Method in Tubular Linear Induction Motor (TLIM의 권선밥법 개선의 관한 연구)

  • 임달호;홍정표
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.6
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    • pp.885-895
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    • 1994
  • In this paper, we propose the one-Ampere conductor method which is able to calculate the flux distribution conceptually and easily, and the improved winding method which suppresses space harmonics of magnetormotive force and enhances the coefficient of utilization of primary iron core in tubular linear induction motor. We carry out no-load test to verify effectiveness of proposed method and analyze characteristics by finite element method. As a result, performances are improved and propriety of primary iron core is enhanced comparing with conventional model.

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Utilization of Alunite to Ceramic Raw Materials (III) (요업원료로서 명반석의 이용에 관한 연구(제III보) Mullite질내화재원료로의 이용)

  • 백용혁;최상흘
    • Journal of the Korean Ceramic Society
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    • v.11 no.3
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    • pp.33-38
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    • 1974
  • The possibility of the sources for the manufacture of mullite-rich refractories from the modified domestic alunite was studied. The modifying method of alunite studied were performed by calcination, wet ballmilling, and washing with water. For synthesis of mullite-rich refractories, the modified alunite with the addition of alumina and Fe2O3 as mineralizer was fired at 1350$^{\circ}$-155$0^{\circ}C$, and the following results were obtained: 1) The suitable firing temperature range was 1450$^{\circ}$-150$0^{\circ}C$, and adequate amounts of Al2O3 and Fe2O3 were below 30% and 3~4%, respectively. 2) Thermal expansion coefficient proportional to heating temperature was about 5$\times$10-6~10$\times$10-6cm/cm.deg. 3) The mineralogical compositions of the sintered specimens were found as mainly mullite and corundum.

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LED module for a desk lamp (탁상 스탠드용 LED모듈)

  • Kang, Seok-Hoon;Shin, Kyung-Ho;Yeo, In-Seon
    • Proceedings of the KIEE Conference
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    • 2003.07c
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    • pp.1713-1715
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    • 2003
  • This paper describes an LED module for a desk lamp using 1[W] high flux while LEDs. The optimum length of the module is obtained from the lighting simulation of the target area of $500{\times}500[mm]$ on the desk, which in turn determines an optimum separation between LEDs. The main issue is to find the optimum separation which gives good illuminance uniformity and high coefficient of utilization at at various reflector structures. Two module configuations of linear and ring types are compared. As a result, good illuminance uniformity is obtained in the case of the ring module. The mofied twin type, however, gives better performance than the ring module, and shows the most performance at an separation angle of around $30^{\circ}$.

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