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Secondary phases precipitation in the 2510 duplex stainless steel
No full textDuplex and superduplex stainless steels are prone to secondary phases (sigma, chi, nitrides, secondary austenite) precipitation in a wide temperature range (500-1000°C), with different sequence and kinetic which depend on the chemical composition and thermo-mechanical history of the steel.
These phases negatively affect the mechanical and corrosion resistance properties of the steels and a drastic drop of toughness has been verified at low intermetallic contents, quite undetectable by optical microscopy.
In this paper the effects of isothermal ageing (5-30 min in the 850-1080°C range) on the microstructure of a super duplex 2510 are presented. The high contents on Ni and N gamma-stabilizer elements are required for the use as welding material.
The phase transformations were investigated by optical, scanning electron microscopy and X ray diffraction, chi and sigma were identified and quantified on the chemical composition base on BSE images. Chi precipitates as small micrometric sized particles at grain boundaries while sigma grows inside the ferrite with the typical butterfly morphology. Nitrides were detected at grain boundaries.
The effect of alloying elements on chemical composition and on amount of secondary phases is discussed. The noses of the TTP curves are at 1000°C (sigma phase) and at 900° C (Chi phase) with a partial transformation of Chi to sigma, as evidenced in 2205 and 2507 Stainless Steels grades.
The obtained data confirm that the examined steel is very prone to phase transformation and that the quantification of precipitated phases have to be performed with image analysis on SEM-BSE micrographs
Roman bricks from the Lagoon of Venice: a chemical characterization with methods of multivariate analysis.
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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
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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