1,720,999 research outputs found
HYBRI – A combined Savonius-Darrieus wind turbine: Performances and flow fields
No full textIn this paper, wind tunnel measurements on a model of a vertical axis wind turbine (VAWT) are reported. The turbine is a novel hybrid Savonius-Darrieus combined rotor which aims optimizing performances in medium-low wind regimes, by using a careful design of the shape, size and relative positions of Savonius and Darrieus blades. To this end, a dynamically scaled turbine model is tested in wind tunnel to derive instantaneous and averaged velocity fields by means of Particle Image Velocimetry (PIV), which allows deriving wakes and specific fluid flow phenomena on each single configuration (Savonius or Darrieus) and interactions on the combined geometry. These results are coupled with electrical measurements to determine global performances, efficiency and best working conditions for each separate turbine and for the combined turbine. Data are also compared with results obtained by other authors in previously reported combined hybrid configurations. The proposed system is able to work with good performances (power coefficient equal or slightly lower than 0.2), on an extended range of operative conditions, covering those of each component alone, i.e. for tip speed ratios between 0.5 and 4, in comparison to the ranges 0.5 ÷ 1 and 1.7 ÷ 4 of the used Savonius and Darrieus components. Motivations for the increased performances and working ranges reached by the proposed combined turbine, especially in the low tip speed ratio regime, are given as derived from detailed PIV velocity measurements
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
A Modified Dynamic Model for Planar Microwave Circuits
No full textA modified version of the moments method for planar circuit simulation, based on fundamental mode sampling, is presented. Fundamental mode sampling substantially reduces the complexity of the analysis and the computation time involved in the characterization of all practical discontinuities. The numerical results are in very good agreement with experimental dat
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
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