1,720,976 research outputs found
Metal dusting: relationship between alloy composition and degradation rate
No full textThe authors have identified a compositional relationship between several commercially available wrought alloys, focussing only on the iron, nickel, chromium and aluminium content. The degradation rate due to metal dusting varies with the surface condition of each alloy: a ground surface condition corresponds to smaller mass losses than a pickled surface condition. The authors have derived a relationship between the maximum observed degradation rate due to metal dusting and the chromium plus aluminium content of each alloy. This relationship has been verified by comparing data from several exposures using different gas compositions and pressures. The results indicate that for the gas used in this exposure, the degradation rate strongly decreases up to a chromium plus aluminium content of 33 wt-%. Above this value, the mass loss rate is negligible. The current relationship is also found valid for aluminide diffusion coatings. © 2009 Institute of Materials, Minerals and Mining
Applicability of coatings to control metal dusting
No full textWe have performed a long term comparative study between five wrought and three centricast materials, both as-is, and in coated condition. Two commercially available coatings were applied to each different alloy. One coating was aluminum based with a chromium rich intermediate layer. The other coating was nickel rich with substantial amounts of silicon and aluminum. Both types of coating were of good quality, and did not show (micro)defects. The coated and bare alloy samples were exposed in a high pressure metal dusting atmosphere, and characterised based on mass loss, pit depth, pit size and pit density at regular intervals. The results indicate that a properly applied coating can boost the metal dusting resistance of low chromium alloys to a level comparable with alloy 693, for which generally no metal dusting attack is observed. Finally, the effect of micro cracks on the coating performance was assessed. ©2009 by NACE International
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
On the microstructure of bituminous binders
No full textThe objective of this work is to study the common features and the evolution of microstructures of bituminous binders regardless of their grade (PEN 10/20 to 160/220) and source/origin using the atomic force microscope operated in phase contrast mode. All bituminous binders show the same microstructural features, consisting of three distinct phases, the perpetua-, peri- and catana-phase. The perpetua-phase is soft and viscoelastic in nature, the peri-phase is relatively stiff and solid in nature and the catana-phase is alternatingly hard and soft in nature and is always found in the middle of the peri-phase. Experiments at different temperatures result in a quantitative picture of the changes/transitions between the different microphases upon heating. Phase formation is reversible with respect to temperature, upon heating homogenisation occurs and upon cooling re-formation of the phases can be observed. © 2013 © 2013 Taylor & Francis
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