• Title/Summary/Keyword: Efficiency Elevation

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A Study on the Flow Characteristics according to the Shapes of Rod on Impinging Jet by PIV Measurement (충돌 Jet에서 Rod 형상에 따른 유동특성의 PIV 계측에 의한 연구)

  • 나우정;정진도;송민근;이상범;손승우;주은선
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.1
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    • pp.152-161
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    • 2004
  • The thermal load is a very important problem to be solved in many industrial systems including the electronic equipment. Impinging Jets have been known to provide a large heat transfer rates on surface for many years. The turbulence enhancement of fluid flow is requested for the efficiency elevation of heat transfer. A study on flow fields by rods attached to the wall surface as a promoter of turbulence enhancement has been carried out. The exact analysis on chracteristics of impinging jet field is requested to obtain the optimum design of the impinging jet system. By visualizing the flow field and processing the high digital image by computer PIV can afford exact data on the velocity vector kinetic energy and turbulence intensity in the complex turbulence field. In this study. three kinds of rod shape such as square. triangle. and semicircle are selected as the turbulence promoter. Nozzle diameters are 10mm. 17mm. and 23mm. And the analysis of the flow characteristics due to the above rods is carried out at Re No. 2.000, 3.000. and 4,000 by PIV measurement. It is clarified that the rod setup is very useful to obtain the turbulence enhancement and the turbulence intensity according to the shapes of rod appears large in order of the shapes of rod such as square 〉 triangle 〉semicircle.

Effect of Fin Pitch on Air Side Heat Transfer in Louvered-Fin Heat Exchanger (루우버핀 열교환기의 핀피치가 공기측 열전달에 미치는 영향)

  • Jang, B.J.;Kim, S.J.
    • Solar Energy
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    • v.20 no.3
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    • pp.31-38
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    • 2000
  • In order to study on influence of fin pitch and shape of heat exchanger on the elevation of heat transfer efficiency, we make models of louvered fin type heat exchanger which was given a transformation of fin pitch in louvered fin type heat exchanger which are of en used now. And the influence of fin pitch on pressure drop and characteristics of heat transfer was experimented and analysed when air velocity and fin pitch was a variable. The results of experiment shows below. Pressure drop shows larger in louvered fin type heat exchanger than in plate fin type heat exchanger, size of pressure drop shows like this order that fin space is 4mm, 5mm, 6mm. Mean heat transfer coefficient shows higher in louvered fin type heat exchanger than in plate fin type heat exchanger, size of mean heat transfer coefficient by fin space shows same in both case in louvered fin type heat exchanger and plate fin type like this order that fin space is 4mm, 5mm, 6mm.

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Effects of Calcium Intake on Lipid Contents and Enzyme Activity in Rats of Different Ages (연령이 다른 흰쥐에 있어 칼슘이 섭취수준이 체내 지질함량과 효소활성에 미치는 영향)

  • 최미경
    • Journal of the East Asian Society of Dietary Life
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    • v.8 no.1
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    • pp.9-19
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    • 1998
  • The purpose of this study was to investigate the effect of calcium intake on lipid contents and enzyme activities in rats of different ages. Lipid levels in serum and liver and GOT, CPK and LDH activities in serum were compared in rats of different ages(4 weeks and 10 months) that were fed various levels of calcium(50, 100, 200% of requirement)for 3 weeks. Body weight gain and feed efficiency ratio were significantly higher in young rats than in adults. Serum calcium level was increased by elevation of calcium intake levels were decreased. Liver phospholipid and triglyceride levels in the high-cal-terol and triglyceride levels were decreased. Liver phospholipid and triglyceride levels in the high calcium group were significantly lower than those in other groups. Serum GOT and LDH activities of adults were significantly higher in low-calcium group than those in adequate/high-calcium groups. However, serum CPK activity of adults was significantly higher in high-calcium group than that in low/adequate-calcium groups. The results of this study suggest that adequate calcium intake may have protective effects ont he alteration of lipid and enzyme activity in rats.

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A Model of Maintenance Management System for Public Rental Housing Utilizing Personal Digital Assistant (휴대형 정보단말기(PDA)를 활용한 공공임대주택 유지관리시스템 모델)

  • Lee, Seok-Won;Won, Jo-Youn;Kim, Chang-Duk;Yu, Jung-Ho
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.781-786
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    • 2007
  • According to increase in supply of public rental housing, in connection with support plan of housing welfare from government, necessity of maintenance management is coming to be important. By analyzing characteristics of public rental housing and maintenance management system, this study grasped developmental possibility of a web based maintenance management system as well as a critical point for improvement of problem and elevation of efficiency about maintenance management process. As we present not only useful possibility of ubiquitous equipments utilizing IT like PDA but effectiveness by using, based on this result, we represent course of improvement to systematic development for user that complement the existing maintenance management system which is currently developed.

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Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus

  • Xing, Hong-yan;He, Gui-xian;Ji, Xin-yuan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1697-1704
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    • 2018
  • As a key component of lighting location system (LLS) for lightning warning, the atmospheric electric field measuring is required to have high accuracy. The Conventional methods of the existent electric field measurement meter can only detect the vertical component of the atmospheric electric field, which cannot acquire the realistic electric field in the thunderstorm. This paper proposed a three dimensional (3D) electric field system for atmospheric electric field measurement, which is capable of three orthogonal directions in X, Y, Z, measuring. By analyzing the relationship between the electric field and the relative permittivity of ground surface, the permittivity is calculated, and an efficiency 3D measurement model is derived. On this basis, a three-dimensional electric field sensor and a permittivity sensor are adopted to detect the spatial electric field. Moreover, the elevation and azimuth of the detected target are calculated, which reveal the location information of the target. Experimental results show that the proposed 3D electric field meter has satisfactory sensitivity to the three components of electric field. Additionally, several observation results in the fair and thunderstorm weather have been presented.

Development of Dental Patient Education System using Mutimedia (멀티미디어를 이용한 치과환자교육 시스템 개발)

  • Kim, M.S.;Lee, S.J.;Nam, G.K.;Kim, H.I.;Lee, Y.W.;Jun, K.R.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.11
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    • pp.52-56
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    • 1996
  • The elevation of present medical service using advanced science contributes to offer medical examination and treatment of good quality under the subject of patient satisfaction as well as patient impression. The dental service field charging some part of public health promotion and public welfare promotion also intends to improve the dental examination and treatment quality utilizing advanced science. The object of this research is the development of dental patient education system (DPES) using multimedia of new technology. DPES can be employed for these object, harmonious operation of dental examination and treatment, treatment quality improvement, disease notice to patient under the subject of patient satisfaction and patient impression, explanation of some selective treatment course, the verification of treatment necessities and treatment validation, and the improvement of treatment effect through the oral cavity sanitation education in the sense of prevention. This research also serves the development environment, the step to collect educational document, visual information and to structure those, and the examination of DPES efficiency in clinic.

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Analysis of the Spatial Configuration of Lobby in General Hospital (종합병원 로비의 기능요소에 따른 공간구조 분석)

  • Choi, Inyoung;Park, Heykyung
    • Korean Institute of Interior Design Journal
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    • v.26 no.1
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    • pp.134-141
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    • 2017
  • General hospitals in Korea have increased more in size since 2000, and as not only medical service but the quality of the environment also got important, the considerable changes have appeared revolving around the lobbies. This study is a basic research to find a direction of a plan for general hospital lobbies in response to the demands that change. It was examined the current condition of lobbies so as to derive the idea of types of lobbies and of functional elements, and based on the research, it was compared and analyzed in terms of the spatial configuration to draw the characteristics by type. The result of the research is as follows. (1) The lobbies were explored after being classified into four types; the plan(central type/street type) and the elevation(eclectic type/double-story type). (2) The hall and corridor were ranked high in order of importance in the whole spatial configuration, and it has been utilized in various ways. (3) Also, each type differed with the others in its main functional area, regarding traffic line efficiency and spatial intelligibility.

Land Use Classification of TM Imagery in Hilly Areas: Integration of Image Processing and Expert Knowledge

  • Ding, Feng;Chen, Wenhui;Zheng, Daxian
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1329-1331
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    • 2003
  • Improvement of the classification accuracy is one of the major concerns in the field of remote sensing application research in recent years. Previous research shows that the accuracy of the conventional classification methods based only on the original spectral information were usually unsatisfied and need to be refined by manual edit. This present paper describes a method of combining the image processing, ancillary data (such as digital elevation model) and expert knowledge (especially the knowledge of local professionals) to improve the efficiency and accuracy of the satellite image classification in hilly land. Firstly, the Landsat TM data were geo-referenced. Secondly, the individual bands of the image were intensitynormalized and the normalized difference vegetation index (NDVI) image was also generated. Thirdly, a set of sample pixels (collected from field survey) were utilized to discover their corresponding DN (digital number) ranges in the NDVI image, and to explore the relationships between land use type and its corresponding spectral features . Then, using the knowledge discovered from previous steps as well as knowledge from local professionals, with the support of GIS technology and the ancillary data, a set of conditional statements were applied to perform the TM imagery classification. The results showed that the integration of image processing and spatial analysis functions in GIS improved the overall classification result if compared with the conventional methods.

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Study on the Preparation of Alginic Acid-PMMA Graft Polymer and the Surface Modification of Montmorillonite with the Graft Polymer (Alginic Acid-PMMA Graft Polymer의 합성 및 이를 Coupling제로 한 Montmorillonite 표면의 개질화에 관한 연구)

  • 손차호;김경환;박천욱
    • Textile Coloration and Finishing
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    • v.4 no.4
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    • pp.81-89
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    • 1992
  • Graft polymers of alginic acid-PMMA, different in composition and Mv of branched PMMA, were prepared by emulsion graft polymerization at various MMA concentrations. In aqueous dispersion solution, the adsorption of graft polymer on the montmorillonite was carried out to modify the surface property of powder, and the adsorption of PMMA in organic solvents (acetone, benzene) on the modified surface of powder were observed. The results obtained were as follows. 1. In emulsion graft polymerization of MMA on the sodium alginate in aqueous solution, SA conversion, MMA conversion and % grafting were increased with increasing MMA concentration where as graft efficiency was decreased. 2. The adsorption amount of graft polymer was increased with the elevation of temperature and the increased of dispersion concentration and with the increase of branched PMMA composition of graft polymer. 3. In organic solvent, the adsorption of PMMA on the surface modified particle was proceeded by the orientation along the stretched branched PMMA of adsorbed graft polymer which is in radial direction to the particle surface. 4. The adsorbed amount of PMMA was increased as the temperature and concentration of PMMA solution, the branching of adsorbed graft polymer and the solvency of solvent were increased.

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Work Stress and Affecting Factors of Emergency Medical Technicians (응급구조사의 업무 스트레스와 그 영향 요인)

  • Jo, Hyeon Tae
    • The Journal of Korean Society for School & Community Health Education
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    • v.15 no.3
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    • pp.95-103
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    • 2014
  • Objectives: To identify work stress and affecting factors of the emergency medical technicians(EMT) and to provide basic data for work circumstance improvement and emergency medical service and duty efficiency elevation. Methods: The data were collected by questionnaire from 635 emergency medical technicians throughout the whole country from August 5 to September 20 2013 and analyzed by using the SPSS(version 18.0) program. Factors affecting stress were analyzed by Multiple Linear Regression Analysis(${\alpha}=0.05$). Results: Mean level of job stress was markedly high in the spot situation(3.43 point), user awareness(3.31 point), burden related to work(3.21 point), role and conflict as a professional job(3.10 point), unsuitable treatment(2.95 point) but was lowest in specialty demand of knowledge and skill(2.76 point). Conclusions: To diminish work stress, understanding and cooperation of the residents and reduction of burden related to work must be improved. Above all, positive interest of 119 and related organ and duty environment improvement will and effort and continuous measure establishment and support and cooperation of the government are needed.

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