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Corrosion behaviour of Duplex stainless steel in organic acid aqueous solutions
No full textThis paper reports on mass loss and electrochemical polarization behaviour of two duplex stainless steels, SAF2205 and SAF2507, in aqueous
solutions of acetic acid, formic acid and their mixtures, in the presence of specific contaminant, e.g. sulphuric acid. The effect of temperature and
redox couples was also investigated.
Both steels withstand corrosion in acetic acid solutions in a wide temperature and concentration range. The corrosion rate is higher in the more
dissociated formic acid at the same concentration. Uniform corrosion with selective dissolution of the austenitic phase was observed in all tested
solutions, being more pronounced with increasing solution aggressiveness.
The presence of sulphuric acid is severely detrimental to the corrosion resistance. The corrosion rate increases almost linearly with H2SO4
concentration. The addition of few tens of ppm of oxidant species such as hydrogen peroxide and Fe3+ or Cu2+ improves the corrosion performance
markedly, leading to corrosion rates close to zero. In particular, the addition of H2O2 increases the corrosion potential up to the passivity of the
steels owing to the possible formation of peracids
Detection of sigma phase by electrochemical methods in a 22%Cr DSS
No full textDuplex stainless steels (DSS) may undergo various structural transformations as a function of temperature, leading to formation of secondary phases when exposed at temperatures in the range 600-1000 C° for prolonged periods of time. Among these phases, apart from carbides and nitrides, sigma is the most prominent intermetallic compound, since it is known to adversely affect the mechanical properties and corrosion resistance of DSS alloys as a consequence of depletion of Cr and Mo in the boundary zones of ferrite grains. As a result of sigma precipitation, DSS become susceptible to localized corrosion via a mechanism similar to sensitization in austenitic stainless steels. Electrochemical methods, reported to successfully detect sensitization in austenitic SS have been applied with the aim to define reliable test conditions with appropriate sensitivity also for DSS. A modified Electrochemical Potentiokinetic Reactivation (EPR) method was developed for investigating DSS sensitivity under different thermal cycles. Modifications were designed by closely analysing DSS anodic behaviour changes with respect to the operating testing conditions. All findings were confirmed by SEM, optical microscopy (OM) examinations and XRD analysis
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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