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Cermodel 2013: Modelling and Simulation Meet Innovation in Ceramics Technology, July 10-12, 2013, Trento, Italy (Editorial)
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Electrochemical behavior of ZrB2 in aqueous solutions
No full textThe corrosion behavior of a dense ZrB2 material (hot pressed with 2.5 wt % Si3N4 as a sintering aid) in aqueous acid solutions containing different aggressive anions such as chlorides, perchlorates, sulfates, oxalates, and fluorides was investigated by means of several experimental techniques. The methodology adopted consists in polarization curve recording, gravimetric corrosion rate determination, and potentiostatic tests coupled to solution analysis, scanning electron microscope observations and X-ray photoelectron spectroscopy surface chemical characterization. During the corrosion process, ZrB2 is converted into both soluble [boric acid and complexes of the different anions with Zr(IV)] and insoluble (mainly ZrO2) corrosion products. The experimental results, compared to literature data, show that the higher the stability of the Zr(IV) soluble complex formed by a particular anion, the higher the corresponding solution aggressiveness and consequently the lower the protectivity of the surface oxide film. The solution aggressiveness was found to increase in the following order: perchlorates = chlorides << sulfates = oxalates < fluorides
Studio del comportamento alla corrosione del diboruro di zirconio in soluzioni acquose
No full textIl diboruro di zirconio (ZrB2) sinterizza, con difficoltà, a temperature superiori a 1700°C e in presenza di pressione. La microstruttura del materiale, contenente 2.5% di Si3N4 come additivo di sinterizzazione, è stata studiata con osservazioni al microscopio elettronico (SEM), tramite spettroscopia a dispersione di energia (EDS) e diffrattometria dei raggi X (XRD). Lo studio del suo comportamento alla corrosione è stato condotto in soluzioni acquose acide contenenti anioni diversi, quali cloruri, fluoruri, perclorati, solfati e ossalati, alla temperatura di 45 °C. Le tecniche elettrochimiche utilizzate consistono nella registrazione di curve di polarizzazione e in misure potenziostatiche e sono state affiancate da analisi chimiche delle soluzioni
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
Microstructure design of liquid phase sintered silicon carbide in function of the powders characteristics
No full textDifferent LPS-SiC were produced by pressureless sintering in argon atmosphere, starting
from different powders: either alfa-SiC or Beta-SiC or mixtures of alfa and beta-SiC, using the same sintering
aid system (Y2O3+Al2O3). The green densities and the densities after various sintering tests
(Temperature range from 1850 to 1900° and holding time 1-2 hours) were related to the powder
characteristics and to the processing conditions. The microstructure of materials from alfa-SiC powder
is generally equiaxed and fine (grain size from 0.5 to 3.5 μm), while the use of beta-SiC powder
favours the development of elongated grains (up to 7 μm) with a mean aspect ratio of about 4. It is
possible to tailor morphology and grain size with a proper selection of powder mixtures alfa/beta-SiC.
Mechanical properties were evaluated on selected samples
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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