1,721,197 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
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
Electrochemical corrosion behaviour of 90-10 Cu-Ni alloy in chloride-based electolytes
No full textThe corrosion of 90–10 copper–nickel alloy in aqueous chloride electrolytes has received considerable attention in the literature due to its widespread use in seawater and saline environments. From an analysis of the electrochemical behaviour of the alloy, it is clear that both the polarization and mixed/corrosion potential characteristics show a close comparison to unalloyed copper. Important differences arise, however, due to the semi–conducting nature, composition and overall protectiveness of the corrosion products on the 90–10 copper–nickel alloy. In this work the metallurgy, electrochemistry and mechanism of passivation of the alloy are reviewed to provide a focused source of data regarding the electrochemical characteristics of the alloy in saline media
Flow influenced electrochemical corrosion of nickel aluminium bronze – Part II. Anodic polarisation and derivation of the mixed potential
No full textThe mixed charge and mass transfer influenced anodic current response of CA 104 nickel aluminium bronze (NAB) is presented as a function of both laminar (rotating disc electrode) and fully turbulent (rotating cylinder electrode) fluid flow. At low values of positive polarisation, the overall behaviour of the freshly polished material in filtered and artificial seawaters is closely related to that of unalloyed copper. The primary anodic reaction in this case is the selective dissolution of the copper component via a cuprous di-chloride complex anion. At large positive polarisation, the solid solution mole fraction for the production of a discrete film of protective alumina (Al2O3) is examined as a function of Reynolds number and discussed in terms of a new mechanism for the passivation NAB in seawater. The polarisation data is used to replicate experimental Reynolds number dependent, corrosion potentials and corrosion current densities over a wide range of electrode angular velocities
The performance of marine coatings and pipe materials under fluid-borne sand erosion
No full textA program of tests is described in which pipe materials and steel substrates with various coatings were subjected to fluid-borne sand particle erosion conditions. Sand-water slurry jets were used at velocities between 2–30 m/s and at a jet impingement angle of 90° to create a range of erosive conditions to evaluate the performance of the pipe materials carbon steel AISI 1020, stainless steel AISI 316. Cupro-Nickel 90/10, medium density polyethylene and glass reinforced plastic test coupons. Further tests at an impingement angle of 30° and at 10 and 20 m/s velocity compared the performance of the carbon and stainless steels with various polymeric, metallic and ceramic coatings. Flexible polyurethane seems to have promise for future use in fluid-borne sand particle erosion environments. The erosion mechanisms of flexible polyurethane have been identified as micro-cutting at low angle impingement and fatigue/crack propagation at normal impact
Flow influenced electrochemical corrosion of nickel aluminium bronze – Part I. Cathodic polarisation
No full textThe cathodic polarisation behaviour of CA 104 nickel aluminium bronze (NAB) has been examined in fully characterised seawaters (filtered and artificial) using the rotating disc electrode (RDE) and the rotating cylinder electrode (RCE). Linear sweep voltammetry and a potential step, current transient technique were used to examine the charge transfer and mass transfer controlled cathodic response as a function of both laminar and turbulent fluid flow. For freshly polished surfaces, the rate of irreversible charge transfer controlled oxygen reduction is controlled by the exchange of a single electron and hydrogen evolution is only significant at potentials more negative than approximately –1.0 V vs. the saturated calomel electrode (SCE)
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
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