1,720,987 research outputs found
Experimental and numerical study of heat transfer to nanofluid flow in sudden enlargement of annular concentric pipe / Hussein Togun Abdullah
Get PDFTurbulent heat transfer to separation nanofluid flow in annular concentric pipe has been studied numerically and experimentally. In numerical study, finite volume method with standard k-ε turbulence model in three dimensional domains is used. Three different types of water based (Al2O3, CuO, TiO2) nanofluids have been employed in this simulation. The adopted boundary conditions were expansion ratio (ER= 1.25, 1.67, and 2), Reynolds number ranging from 20000 to 50000, and Al2O3, CuO, TiO2 water based nanofluids with volume fractions varied between 0 to 2% at heat flux varied from 4000 W/m2 to 16000 W/m2. For experimental study, Al2O3 water based nanofluid was used to validate numerical results. The outer cylinder of downstream section was heated by uniform heat flux whereas the outer cylinder of upstream section and the overall length of the inner cylinder were unheated. The results show that the volume fraction of nanofluid and Reynolds number significantly affect the surface heat transfer coefficient; an increase in surface heat transfer coefficient was noted when both volume fraction of nanofluids and Reynolds number were increased for all the cases. The peak of the heat transfer coefficient had occurred after the sudden expansion moved far from the step height with the increase of sudden expansion dimensions due to separation flow in case of both pure water and nanofluid. It has been noted from the counter of streamline the size of recirculation zone increased with the increases of Reynolds number and expansion ratio. Increase of volume fraction of nanofluid enhances the heat transfer coefficient due to augmented heat transport by nanoparticles in base fluid which raises the convection heat transfer. The lowest pressure drop and maximum thermal performance are observed at Reynolds number 50000, 2% Al2O3 water based nanofluid at expansion ratio 2 in comparison to others. The improvement of heat transfer was about 36.6 % for pure water at expansion ratio 2 compared to heat transfer obtained in straight pipe. Augmentation of heat transfer could be achieved by using nanofluid at expansion ratio 2 where the total improvements were about 45.2% (TiO2), 47.3 %(CuO), and 49 %(Al2O3). Also the increment in the pressure drop was about 42% for pure water at expansion ratio 2 compared with straight pipe whereas by using nanofluid they were 62.6% (TiO2), 65.4% (CuO), and 57.6% (Al2O3). Good agreements were observed between numerical and experimental results all the way.
Extension studies on thermal performances and pressure drop for separation flow over single or double and Forward or Backward-Facing steps have also been performed. Studies were conducted numerically with different models for flowing water and different types of nanofluids. Here heat transfer and pressure drop enhancements were observed following the similar trend obtained for sudden expansion configuration
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
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
Laminar CuO–water nano-fluid flow and heat transfer in a backward-facing step with and without obstacle
Get PDFDispelling 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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