1,720,964 research outputs found
Experimental and kinetic modeling study of PAH formation in methane coflow diffusion flames doped with n-butanol
Full text linkIn order to understand the interactions between butanol and hydrocarbon fuels in the PAH formation, experimental and kinetic modeling investigations were combined to study methane laminar coflow diffusion
flames doped with two inlet mole fractions of n-butanol (1.95% and 3.90%) in this work. Mole fractions of flame species along the flame centerline were measured using synchrotron VUV photoionization
mass spectrometry. A detailed kinetic model of n-butanol combustion, extended from a recent published n-butanol model, was provided in this work to reproduce the fuel decomposition and the formation of benzene and PAHs in the investigated flames. Numerical simulations were performed with laminar-SMOKE code, a CFD code specifically conceived to handle large kinetic mechanisms. The simulation results were able to follow the observed effects of n-butanol addition from the experimental results. In particular, unsaturated hydrocarbons, especially C6–C16 aromatics, were predicted satisfactorily. The reaction flux analysis revealed that benzene precursors, especially C3 radicals, increase significantly with increasing inlet mole fraction of n-butanol. This enhances the formation of phenyl and benzyl radicals, which are important PAH precursors. Reactions of benzyl, phenyl radicals and benzene with C2–C3 species are the major formation pathways for indene and naphthalene. And PAHs with more carbon atoms are dominantly formed from naphthyl and indenyl radicals
Experimental and kinetic modeling study of PAH formation in coflow diffusion n-butanol doped methane flames
No full textIn this work, experimental and kinetic modeling investigations were combined to study the PAH formation in the coflow diffusion methane flames doped with 1.95% and 3.90% of n-butanol, with the help of synchrotron VUV photoionization mass spectrometry method and laminarSMOKE code. The modeling result reveals that benzene precursors, especially C3 radicals, increase significantly while increasing inlet mole fraction of n-butanol. This enhances the formation of phenyl and benzyl radicals which are important precursors of PAHs. Reactions of benzyl, phenyl radicals and benzene with C2-C3 species are major formation pathways for indene and naphthalene
Experimental and detailed kinetic modeling study of PAH formation in laminar co-flow methane diffusion flames
No full textIn the present paper, synchrotron VUV photoionization mass spectrometry is used to study the detailed chemistry of co-flow methane diffusion flames with different dilution ratios. The experimental results constitute a comprehensive characterization of species important for PAH and soot formation under conditions that resemble those of practical flames. In addition to the main C1/C2 species, unsaturated C3 (C3H2, C3H3, aC3H4, pC3H4), C4 (C4H2, C4H4, C4H6), and C6 (C6H2) species as well as first aromatics (C6H6, C7H8, C10H8, C12H8) are detected. The laminar, co-flow flames were simulated using an original CFD code based on the operator-splitting technique, specifically conceived to handle large kinetic mechanisms. The detailed kinetic modeling was effectively used to describe and analyze the fuel consumption and the formation of PAH. Experimental measurements and numerical predictions were found to be in satisfactory agreement and showed the relative importance of the C2 and C3 mechanisms in the formation of the first aromatics
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
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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