1,720,965 research outputs found
대기압 하의 유동 시스템에서 임계열유속 증가에 관한 삼인산나트륨과 붕산의 영향
No full text학위논문(석사) - 한국과학기술원 : 원자력및양자공학과, 2008. 8., [ vii, 33 p. ]The phenomenon which the heat transfer coefficient between a heated wall and fluid with change from the liquid phase to the vapor phase of fluid near the heated wall decreases suddenly is generally called a CHF phenomenon. In case of a heat flux control system, there is a sudden increase of wall temperature. A CHF is a flux at the situation, and this is an important factor in a heat transfer system. The enhancement of CHF means the increase of efficiency of the heat transfer system due to perform normal operation at higher heat flux, and it also means the increase of safety due to increase the safety margin. Therefore, many researchers have studied about methods and applications of the CHF enhancement for 30 years.
In this study, the effect of tri-sodium phosphate (TSP) and boric acid on the CHF enhancement was studied. Both TSP and boric acid are used to control pH in nuclear power plants. TSP is a kind of surfactant, and several surfactants, include TSP, have been reported to have an effect on the enhancement of heat transfer. Nothing has been reported in case of boric acid, yet.
The CHF experiment was performed with mass flux ranged 100-500 and two inlet subcooling temperatures of 25, 50℃ under atmospheric pressure. In case of TSP, one inlet subcooling temperature of 50℃ was used. The test section was vertical circular SS316 tube having the inside diameter of 10.98 mm. The heated length is 224 mm, and it was heated by a heat flux control system using electricity. Fluids filled in the test loop were plain water, TSP solutions, and boric acid solutions. TSP solutions had three concentrations (0.2, 0.4, 0.6%), and boric acid solutions had four concentrations (0.2, 0.4, 0.6, 0.8%).
In case of TSP, 21.4% enhancement of CHF was observed at inlet subcooling temperature of 50℃ and extremely low mass flux (100 ). In case of boric acid, 14% enhancement of CHF was observed at inlet subcooling temperature of 50℃ and extremely low mass flux (1...한국과학기술원 : 원자력및양자공학과
Experimental study on the CHF enhancement in flow boiling system with TSP and boric acid solutions under atmospheric pressure
No full textCHF Enhancement in Flow Boiling System with TSP and Boric Acid Solutions under Atmospheric Pressure
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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
Artificial spores: cytoprotective nanoencapsulation of living cells
No full textIn this Opinion we discuss the development of artificial spores and their maturation as an independent field of research. The robust cell-in-shell structures have displayed unprecedented characteristics, which include the retardation of cell division and extensive cytoprotective capabilities that encompass exposure to osmotic pressure, shear force, heat, UV radiation, and lytic enzymes. Additionally, the nanothin shells act as highly versatile scaffolds for chemical functionalization to equip cells for implementation in tissue engineering, biosensors, cell therapy, or other biotechnological applications. We also explore the future direction of this emerging field and dictate that the next phase of research should focus on attaining more intricate engineering to achieve stimulus-responsive shell-degradation, multilayer casings with orthogonal functions, and the encapsulation of multiple cells for multicellular artificial spores
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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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