• Title/Summary/Keyword: Total heat

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Protection of Canola (Low Glucosinolate Rapeseed) Meal and Seed Protein from Ruminal Degradation - Review -

  • Mustafa, A.F.;McKinnon, J.J.;Christensen, D.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.4
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    • pp.535-542
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    • 2000
  • Canola meal and seed are poor sources of ruminal undegraded protein (RUP). On average, canola meal and canola seed contains 35 and 14% RUP, respectively. Several protection methods are effective in reducing ruminal degradation of canola protein and in increasing RUP without affecting total tract protein digestibility. Heat (e.g., dry heat, moist heat and jet-sploding) and chemical (e.g., formaldehyde) treatments are the most common methods used to reduce ruminal degradability of canola protein. In most cases, heat treatments were found to be more effective than chemical treatments in protecting canola protein form ruminal degradation. Despite improvement in RUP content and intestinal availability of RUP, data form several studies showed little or no improvement in animal performance as a result of increasing the RUDP level of canola meal and seed.

Optimal heat exchanger network synthesis through heuristics and system separation method (경험법칙과 계의 분리법을 통한 최적 열교환망 합성)

  • Lee, Hae-Pyeong;Ryu, Gyeong-Ok
    • Journal of Institute of Control, Robotics and Systems
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    • v.1 no.2
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    • pp.119-126
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    • 1995
  • The purpose of this study is to develop the technique of energy recovery and energy saving by using the optimization of heat exchanger network synthesis. This article proposes a new method of determining the optimal target of a heat exchanger network synthesis problem of which data feature multiple pinch points. The system separation method we suggest here is to subdivide the original system into independent subsystems with one pinch point. The optimal cost target was evaluated and the original pinch rules at each subsystem were employed. The software developed in this study was applied to the Alko prosess, which is an alcohol production process, for the synthesis of heat exchanger network. It was possible to save about 15% of the total annual cost.

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Calculation of the Convective Mixed Layer by Estimation of Sensible Heat Flux (현열 플럭스 추정에 의한 대류 혼합층 고도의 산출)

  • 김용국
    • Journal of Environmental Science International
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    • v.7 no.5
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    • pp.639-645
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    • 1998
  • A Jump model was evaluated for the calculation of hourly mixing height and mean potential temperature within the height. The Sump model was modified for estimation of downward heat fluxes by mechanical convections and surface heat fluxes. The surface heat fluxes were estimated from routine weather data such as solar radiation and air temperature. Total of 8 upper-air data observed at 0000UTC and 0600UTC in Osan station during April 23 to 26, 1996 were analyzed, and compared to the model results in detail. The calculated mixing heights and potential temperatures within the height were comparable to the observations, but some differences were showed. The calculated mixing heights were generally higher than observations. And, when variations of wind directions were large, the large difference of potential temperature was occurred. From the results, it was important to note that vortical motions and advections of air masses would affect to the growth of the mixing height.

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Winding Temperature Measurement in a 154 kV Transformer Filled with Natural Ester Fluid

  • Kweon, Dongjin;Koo, Kyosun
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.156-162
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    • 2013
  • This paper measures the hot spot temperatures in a single-phase, 154 kV, 15/20 MVA power transformer filled with natural ester fluid using optical fiber sensors and compares them with those calculated by conventional heat run tests. A total of 14 optical fiber sensors were installed on the high-voltage and low-voltage windings to measure the hot spot temperatures. In addition, three thermocouples were installed in the transformer to measure the temperature distribution during the heat run tests. In the low-voltage winding, the hot spot temperature was $108.4^{\circ}C$, calculated by the conventional heat run test. However, the hot spot temperature measured using the optical fiber sensor was $129.4^{\circ}C$ between turns 2 and 3 on the upper side of the low-voltage winding. Therefore, the hot spot temperature of the low-voltage winding measured using the optical fiber sensor was $21.0^{\circ}C$ higher than that calculated by the conventional heat run test.

Experimental Study of the Superheat and Control of the Refrigerant Flow-Rate in the Evaporator of a Multi-type Air-Conditioning System (멀티형 공조시스템의 증발기 과열도에 관한 실험적 연구 및 냉매유량 제어)

  • 김태섭;홍금식;손현철
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.221-221
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    • 2000
  • The heat exchange part in a modern multi-type air-conditioning system employs multiple-pass heat exchangers. The heat-transfer performance of an each pass in such an exchanger depends strongly on the length of the two-phase region and the mass flow of the refrigerant. The total length and diameters of the pipes, the exit conditions, and the arrangement of each pass as well as the geometrical shape of the distributor at the branching sections are considered to be major factors affecting the heat-transfer performance. The refrigerant commonly used in these systems is HCFC-22. The two objectives of this paper are to investigate the characteristics of the refrigerant flow rate and the superheat in the evaporator of a multi-type air-conditioning system for a single or simultaneous operating conditions and to control the superheat and the refrigerant flow rate of the evaporator.

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The two-dimensional heat transfer analysis in a fin assembly (Fin Assembly에서의 2차원 열전달 해석)

  • 서정일;조진호;강희영
    • Journal of the korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.36-45
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    • 1984
  • The conventional heat transfer analysis methods based on the one-dimensional theory are not adequate to be applied for the purpose of finned surface design because the two-dimensional effects in fact are induced within the supporting wall by the presence of the finnes. In this study, the two-dimensional heat transfer of a straight fin assembly is analyzed by using the integral method. It is shown that all the effects of the system parameters i.e., the heat transfer parameters and geometrical parameters, on both the total heat transfer rate and the surface temperature effectiveness can be seen from the present analysis. The optimum combinations of these parameters for the design of finned surfaces may be estimated.

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A Study on the Formation of Cavity and Welding Property in the Laser Welding Fusion Zone between Sintered Segment and Mild Steel Shank (소결체와 저탄소강의 레이저용접시 생성되는 캐비티의 형성과 용접 특성에 대한 연구)

  • Cho Nam-Joon;Jung Woo-Gwang;Kim Sung-Wook;Lee Chang-Hee;Kim Sung-Dea
    • Korean Journal of Materials Research
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    • v.14 no.4
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    • pp.300-306
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    • 2004
  • A laser welding has been made between sintered tip of Fe-Co-W and low carbon steel shank for the diamond saw blade. The welding characteristics and formation of defect has been investigated carefully for the weld fusion zone in different welding condition. Full penetration has been observed for the whole range of heat input investigated in the present work. Bead width and under-fill have been increased with the increase of heat input. With increasing of heat input small cavities were decreased while large cavities were increased. The ratio of total cavity area to the entire weld bead area was not changed significantly with change of heat input. Most of cavities were found near the tip, and supposed to be formed from the pore in the tip.

Effect of Diameter and Length on the Absorption Performance in a Vertical Absorber Tube (수직형 흡수기 성능에 미치는 흡수기 전열관의 직경과 길이의 영향)

  • 서정훈;조금남
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.12
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    • pp.1214-1222
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    • 2001
  • The present study investigated the effect of diameter and length on the absorption performance of a vertical falling film type absorber using $LiBr-H_2$O solution of 60 wt%. The parameters were diameter of absorber (17.2, 23.4, 31.1 mm), length of absorber (771, 1150, 1528 mm), and film Reynolds numbers (50, 70, 90, 110, 130, 150). As the diameter of the absorber was increased, the absorption mass flux, Sherwood number, heat flux, and heat transfer coefficient were increased, in which Sherwood number and heat transfer coefficient were increased up to 13% and 30% respectively. As the length of the absorber was increased, the total absorption rate and heat transfer coefficient were increased by 37% and 35% respectively, while the absorption mass flux was decreased.

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Multi-objective Topology Optimization of Magneto-Thermal Problem considering Heat Flow Rate (열 유입률을 고려한 자계-열계 다목적 위상최적설계)

  • Shim, Ho-Kyung;Wang, Se-Myung;Moon, Hee-Gon;Hameyer, Kay
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.138-139
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    • 2007
  • This research provides machine designers with some intuition to consider both, magnetic and heat transfer effects. A topological multi-objective function includes magnetic energy and heat inflow rate to the system, which equals to the total heat dissipation by conduction and convection. For the thermal field regarding the heat inflow, introduced as a reaction force, topology design sensitivity is derived by employing discrete equations. The adjoint variable method is used to avoid numerous sensitivity evaluations. As a numerical example, a C-core design excited by winding current demonstrates the strength of the multi-physical approach.

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A Convective Heat Transfer Correlation for Turbulent Gas-Liquid Two-Phase Flow in Vertical Pipes

  • Kim, Dong-Woo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.4
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    • pp.27-36
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    • 2001
  • A new two-phase non-boiling convective heat transfer correlation for turbulent flow $(Re_{SL}>4000)$ in vertical tubes with different fluid flow patterns and fluid combinations was developed using experimental data available from the literature. The correlation presented herein originates from a careful analysis of the major non-dimensional parameters affecting two-phase heat transfer. This model takes into account the appropriate contributions of both the liquid and gas phases using the respective cross-sectional areas occupied by the two phases. A total of 255 data points from three available studies (which included the four sets of data) were used to determine the curve-fitted constants in the improved correlation. The performance of the new correlation was compared with two-phase correlations from the literature, which were developed for specific fluid combinations.

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