1,720,977 research outputs found
Breakup and breakdown of bent kerosene jets in gas turbine conditions
No full textet A-1 kerosene injection in air crossflow conditions has been studied for temperature up to 600 K and pressure up to 2 MPa. Thousand frames of jet shadowgraphs have been sampled for each of the 82 experimental conditions to determine statistical parameters characterizing the jet behavior. Among them the breakdown point, corresponding to the spatial position along the jet where the momentum jet looses its coherence, is the most relevant one. The axial coordinate of this point is strongly correlated with the liquid–gas momentum ratio while the breakdown position in gas stream direction mainly depends on the aerodynamic Weber number. This shows that the deformation of the liquid before and after its primary atomization is the most significant correction in respect to the ballistic, inviscid evolution of a bent cylindrical jet. The generalized profile equation, normalized to the breakdown coordinates, is invariant in respect of whatever external parameter and it predicts with high level of accuracy the measured profile upstream of the breakdown position
Trajectory and momentum coherence breakdown of a liquid jet in high-density air cross-flow
No full textAn experimental study of a liquid jet injected normal to a high-density air cross-flow is presented. Kerosene and water were used in order to highlight the influence of liquid properties on the jet bending and atomization process. Two different nozzle sizes and two values of the air pressure were used to gain some insight on the dependence of these parameters on the jet evolution. A shadow-graphic technique has been used and an image statistical analysis procedure, allowing for a fully automated determination of the jet momentum coherence breakdown point, was set up. A simple correlation between the coordinates of this point and the ratio of the liquid-to-air momentum (q) and a Weber number was found. Experimentally measured trajectories normalized with respect to the breakdown point coordinates collapse to a unique trajectory, which is well fitted by either a power or a logarithmic curve with only one parameter. This is the base for the definition of a new empirical correlation that, in the explored experimental conditions, performs better than the ones available in the literature. This fact indicates that the operatively defined momentum coherence breakdown concept subsumes the functional dependence of jet behavior on controlling parameters, at least for the explored operating conditions
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
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
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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