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공기와 헬륨 실험루프를 이용한 인쇄형 열교환기의 열유체성능 연구
No full text학위논문(석사) - 한국과학기술원 : 원자력및양자공학과, 2008.2, [ viii, 63 p. ]The wavy channels of a Printed Circuit Heat Exchanger (PCHE) cause physical phenomena such as eddy and recirculation. In its channels both of the overall heat transfer coefficient and the pressure drop are enhanced. We built two test loops to study the thermal-hydraulic performance of a PCHE manufactured by Heatric Company: KAIST Air and Helium Test Loops. The KAIST tests are performed in laminar region. We estimated the fanning factor, overall heat transfer coefficient, and effectiveness based on their experimental data. We developed the empirical correlation for the fanning factor in the micro-wavy channels of the PCHE assuming that the total pressure drop is the sum of friction loss and form loss. From the results of the KAIST Air Test, the fanning factor is the same as that of the semi-circular pipe in the low Reynolds number: when the Reynolds number is lower than 120, the form loss can be negligible. However, the fanning factor in the KAIST Helium Test shows different behavior from that in KAIST Air Test: the loss factor for the pressure drop for Helium flow is much higher than that for air flow. We developed the empirical correlation for the heat transfer coefficient in the micro-wavy channels of the PCHE in the laminar region. The heat transfer coefficient in the PCHE is higher than that in the straight circular tube in the laminar region: it is proportional to the Re number.한국과학기술원 : 원자력및양자공학과
Thermal-hydraulic characteristics of the Printed Circuit Heat Exchanger (PCHE) in a Helium-Water Test Loop
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Cost analysis based on physical models developed for printed circuit heat exchangers with wavy channels in HTGR
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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