1,720,997 research outputs found
Kinetics of deuteration of the Pd0.772Ag0.228 alloy with α/β phase transition by in-situ neutron diffraction
Full text linkThe deuteration reaction of a Pd0.772Ag0.228 foil was studied by neutron powder diffraction measurements vs. time in different T and p(D-2) conditions (D20 and D2B high-resolution diffractometers at ILL, France). The system has great importance as permeable membrane for hydrogen separation. At p = 1 bar and T < 200 degrees C Bragg peak splitting indicates the presence of two cubic phases, to be identified with the a and beta modifications of palladium hydride. Rietveld refinements provided the corresponding a(alpha), and a(beta) lattice constants, the nu(alpha), and nu(beta) occupancies of D, and the beta phase volume fraction vs. time during deuteration progress. A continuous alpha -> beta transformation takes place till reaction end. At T= 200 degrees C or p> 1 bar a single phase was always observed. The phase diagram of Pd0.772Ag0.228D nu is thus shown to present a alpha+beta two-phase domain less extended but similar to that of PdH nu, at variance with most thermodynamic measurements suggesting full single-phase behavior. The p(t) kinetic data of deuteration at 80 degrees C/1 bar can be interpreted by a mechanism based on a first-order nucleation step followed by a zero-order step of surface adsorption and dissociation of the D-2 molecule. (C) 2019 Elsevier B.V. All rights reserved
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
Neutron diffraction study of the Pd0.772Ag0.228DΝ membrane for hydrogen separation
No full textExperiments of deuterium absorption/desorption were performed on a foil of Pd77Ag23 (wt %) alloy in the 78-196 degrees C temperature and 1-4 bar pressure ranges under the neutron beam at ILL (Grenoble). Powder diffraction patterns were collected on the D1B diffractometer (lambda = 1.2871 angstrom) on the Pd0.772Ag0.228Dv deuterated alloy, and the face-centred-cubic structure was Rietveld-refined locating the D atom in the octahedral site with a variable occupancy v (=D/M ratio). The results of v(T) curves at different p(D-2) pressures are discussed in comparison with literature data on H and D absorption into Pd-Ag alloys from thermodynamic measurements. A negative deviation from predictions of Sieverts' law is shown by the dependence of D occupancy on pressure. This effect relates the behaviour of the activity coefficient TD to D-D and D-M interactions in the solid solution phase. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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