1,720,959 research outputs found
Mechanical and tribocorrosion properties of HVOF sprayed WC-Co coatings
No full textHVOF technology has been proposed in recent years for the production of engineered cermet coatings suitable for the replacement of hard chromium surface treatments of mechanical components, for aeronautical and automotive applications. The aim of this study has been to compare the mechanical and tribocorrosion properties of WC-Co cermet coatings fabricated with different processing parameters, to optimise the spraying process by evaluating the dependence of the macroscopic coating properties on the spraying procedure. Barrel length, oxygen:fuel ratio and torc-1 specimen spraying distance were selected as the main variables since their influence on cooling microstructure and macroscopic properties in the absence of corrosion is already well known. WC-Co samples were subjected to 'block on ring' wear testing, carried out in an electrochemical cell, to assess wear properties in combination with a range of corrosive conditions. The results were compared to those obtained by ordinary wear testing and electrochemical characterisation. Mechanical properties of the coatings, such as microhardness, fracture toughness and coating substrate adhesion, were also measured. Tribocorrosion testing proved better able to distinguish coating properties than conventional wear tests, due to the more severe damage induced by the corrosive attack
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
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