1,721,056 research outputs found
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
An algorithm for extracting chemical reactor network models from CFD simulation of industrial combustion systems
No full textChemical engineering models significantly reduce the amount of computational time for detailed chemical kinetics with respect to the direct implementation of a three-dimensional CFD code, but to be of real aid in dealing with industrial problems, they should be generated from CFD outputs in an automatic and objective way that does not depend on the specific case to be modeled. In the present study, the features of an algorithm developed and encoded for this purpose are shown: The criteria and logical steps adopted in generating chemical reactor networks (CRNs) from CFD simulation of industrial combustion devices are presented, and a method for evaluating the accuracy of the simplification is discussed. The assessment of the algorithm focuses on its performance in yielding CRNs capable of reproducing the concentration of main species calculated by CFD. This is a necessary condition for the subsequent use of comprehensive and detailed reaction schemes for the prediction of pollutant and harmful species involved in combustion
Modelling practical combustion systems and predicting NOx emissions with an integrated CFD based approach
No full textAn integrated methodology for the simulation of practical combustion systems and NOx prediction is presented. It is based on 3D CFD simulation coupled to a postprocessor which yields reactor networks, extracted from 3D fields, as 'equivalent' simplified flow models for which it is possible to use a detailed reaction kinetics. The study of two glass melting furnaces is presented to illustrate the methodology. The furnaces were experimentally characterised, then CFD simulations were performed, setting the suitable boundary conditions for the radiative heat exchange and the sub-model for the chemistry. From each CFD simulation, a chemical reactor network was extracted to perform the computation of the secondary product combustion species by means of a complex kinetics mechanism. An evaluation of the models was given comparing the measurements with the temperature of the CFD field and the NOx prediction. Finally, an estimate of the effect of some NOx reducing techniques was given. (C) 2002 Elsevier Science Ltd. All rights reserved
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
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