1,721,005 research outputs found
Sol-gel synthesis of Na+ beta-Al2O3 powders
No full textPowders of general formula Na1+xAl11O17+x/2 with x=0, 0.2 and 0.57 have been obtained by hydrolysis and condensation of
metal alkoxides. X-ray diffraction investigations showed the crystallization of b-alumina peaks at 1100 C, confirmed by DTA/TG
measurements. The same phase was revealed for pellets sintered in air at 1400 C. Densities up to 97% of the theoretical value were
reached. Electrical performances of pellets of x=0.2 and 0.57 compositions were investigated by Dielectric Analyzer (DEA) at
various frequencies. The measured values confirmed the good conductivity and activation energy performances of the material
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
Hydrogen desorption from magnesium hydride - graphite nanocomposites produced by ball milling
No full textAbstract
Magnesium hydride–graphite composites produced via ball milling exhibit fast H2 desorption/absorption kinetics; moreover, their activation behaviour is particularly attractive if compared with MgH2-based materials obtained so far. In this work, we report the phase analysis (by X-ray diffraction) and investigate the crystal structure and the desorption behaviour (using a home-made Sievert apparatus) of MgH2–graphite composites produced by ball milling. Milling with graphite is found to improve the desorption rate of MgH2 changing the reaction mechanism
Sol-gel synthesis of lambda-Na2O·xAl2O3 films
No full textNa2OxAl2O3 (x = 9, 11) films have been obtained by sol– gel
method. Crystallization processes during heat treatments have
been investigated by X-ray diffraction analysis. A metastable
phase with the mullite structure, lambda-Na2OxAl2O3, has been
observed starting from 800°C. Films remained stable after a
heat treatment at 1000°C for 250 h. Impedance spectroscopy
measurements showed that the films of lambda-Na2OxAl2O3 possess a large three-dimensional ionic conductivity at 400°C
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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