1,721,398 research outputs found
Quantifying the Effects of Rarefaction in High Velocity, Slip-Flow Regime
No full textThe present work follows two former papers by the first author where the effects of rarefaction in transitional regime were considered. In the first paper these effects were evaluated on the aerodynamic coefficients of a re-entering sphere-cone capsule. In the second paper, parameters quantifying non-equilibrium (anisotropy and thermodynamic non equilibrium) were proposed. Both studies were carried out changing at the same time velocity and altitude. In the present paper a sensitivity analysis, for identifying the most critical parameter for non-equilibrium, and an evaluation of the influence of non-equilibrium, slip velocity and temperature jump (slip effects) on the drag and heat transfer coefficients are carried out. Parameters quantifying the slip effects are also proposed. Computer simulations are made on a sphere in slip-flow regime by a: i) DSMC code (DS2V) for the sensitivity analysis and for quantifying the influence of non-equilibrium, ii) Navier-Stokes code (FLUENT) for the evaluation of the slip effects. The sensitivity analysis showed that the influence of the free stream velocity on the non-equilibrium parameters is much stronger than the one of the free stream thermodynamic parameters. Therefore the quantification was carried out changing the free stream velocity; in order to point out only the influence of rarefaction, excluding the fluid-dynamic effects, for each variation of the free stream velocity the thermo-dynamic parameters were adapted in such a way to keep the same value of the free stream Mach, Reynolds, Knudsen, Prandtl and Lewis numbers. The results showed that the influence of non-equilibrium and slip on the aerodynamic coefficients is of the order of one percentage unit. A more consistent difference, between the aerodynamic coefficients from DS2V and from FLUENT, is probably due to the failure of the phenomenological equations of Newton, Fourier and Fick
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 água para a rega em horticultura protegida
No full textNa horticultura protegida obtém-se a mais elevada produtividade e rentabilidade da água,
permitindo a recolha da água da chuva, ou a utilização de águas tratadas. Para assegurar
o desenvolvimento sustentável do território, e face à crescente escassez dos recursos hídricos,
deve-se prever a aplicação de medidas que garantam e aumentem a disponibilidade de água
para a rega, tendo presente o instável equilíbrio entre economia, ecologia e justiça social.info:eu-repo/semantics/publishedVersio
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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