1,721,005 research outputs found
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
Thermal fatigue testing of CuCrZr alloy for high temperature tooling applications
No full textCuCrZr alloy offers good mechanical and thermal properties and was investigated in the present work for its potential as tooling material in thixoforming of steels. Samples of CuCrZr alloy were cycled thermally between 450 and 750 A degrees C, every 60 s. The thermal conductivity of the CuCrZr alloy, nearly an order of magnitude higher with respect to that of the conventional hot work tool steel, proved to be very beneficial in terms of thermal stresses generated at the surface upon thermal cycling. The maximum compressive and tensile stresses produced at the front face of the CuCrZr alloy were estimated to be approximately 30 and 10 MPa, respectively, much smaller than those endured by the conventional hot work tool steel. The very favourable thermal stress state in the CuCrZr alloy die was largely negated, however, due to its inferior resistance to high temperature oxidation
Synthesis of Al-SrB6 composite via powder metallurgy processing
No full textThe potential of powder metallurgy processing for the manufacture of Al-SrB6 composites was explored. Al4Sr particles fractured extensively during the ball milling of Al-15Sr/Al-4B powder mixtures. There was no interaction between the Al4Sr and AlB2 compounds across the section of the aluminium grains in the as-milled state. SrB6 formed, when the ball milled powder blends were subsequently annealed at sufficiently high temperatures. Ball milling for 1 h was sufficient for SrB6 to become the major constituent in powder blends annealed at 700 degrees C while it took 2 h of ball milling for powder blends annealed at 600 degrees C. Higher annealing temperatures and longer ball milling time encouraged the formation of the SrB6 compound while the latter made a great impact on the microstructural features of the Al-SrB6 composite. The SrB6 compound particles were much smaller and more uniformly distributed across the aluminium matrix grains in powder grains ball milled for 2 h before the annealing treatments at 600 degrees C and 700 degrees C
Impact of partial recrystallization on the performance of 6005A tube extrusions
No full textStrain distribution in tube extrusion involves gradients not only across the thickness but also around the diameter in a cyclic fashion favouring recrystallization at the surfaces and weld seams where the peak strains occur. Recrystallized grains are coarse since only a small fraction of the potential nuclei are activated while the rest are pinned by the dispersoids. While coarse surface grain structure is typical in all 6005A tubes, only those with fully recrystallized weld seams have failed. Having been largely depleted of its defects during recrystallization, weld seams respond to a subsequent artificial ageing treatment favourably and enjoy a relatively higher hardness owing to the precipitation of the hardening precursor phases of the Mg(2)Si. The interface between the harder weld seams and the relatively softer fibrous zones is believed to be a weak link, a very favourable site for crack initiation. Once initiated, cracks propagate along this interface until they reach the recrystallized surface layer. The recrystallized weld seams are judged to be a serious threat to the integrity of hollow extrusions. (C) 2010 Elsevier Ltd. All rights reserved
Recrystallization of twin-roll cast Al-Fe-Si foil stock processed without homogenization
No full textDifferential scanning calorimetry, hardness testing, electrical conductivity measurements and microstructural analysis were employed in the present work to investigate the response of twin-roll cast Al-0.8Fe-0.6Si strips to interannealing without prior homogenization. Recrystallization which occurs at 400 degrees C in sheet samples cold rolled only lightly (epsilon similar to 0.2) is gradually displaced to lower temperatures with increasing strain until epsilon similar to 2.3. Precipitation occurs largely before a measurable recrystallization reaction at low strains, epsilon < 2.3, producing an acceptable grain structure across the section. The interaction of the two reactions at epsilon > 2.3 is believed to be responsible for a decreasing recrystallized fraction and for coarse grains at the surface where the interaction is likely to be most pronounced. Interannealing of the Al-0.8Fe-0.6Si alloy without a homogenization treatment produces acceptable grain structures across the section of the strip for much of the cold rolling strain range. It is thus concluded that Al-0.8Fe-0.6Si foil stock, intended for cosmetic foil applications where formability is not critical, could be processed without a high-temperature annealing treatment. (C) 2009 Elsevier B.V. All rights reserved
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