1,720,969 research outputs found
Microstructural characterization and corrosion behavior of lead, bismuth and antimony tellurides prepared by melting
No full textThe corrosion behavior of lead, bismuth and antimony tellurides (PbTe, Bi2Te3 and Sb2Te3) was investi- gated in naturally aerated 0.1 M NaCl solution by open circuit potential and impedance spectroscopy measurements. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS) were used to characterize the samples prior to and after the electrochemical tests. All the investigated tellurides exhibit a one-phase microstructure, as evidenced by SEM characterization. The electrochemical results showed that in sodium chloride solution the corrosion resistance of the PbTe intermetallic com- pound was higher than that of bismuth and antimony tellurides owing to a more stable corrosion prod- ucts laye
Influence of rare earth metals addition on the corrosion behaviour of copper in alkaline environment
No full textEffect of silicon and germanium alloying additions on the passivationcharacteristics of Fe3 Al intermetallic in sulphuric acid solution
No full textInvestigation of passivity and its breakdown on Fe3Al–Si and Fe3Al–Ge intermetallics in chloride-containing solution
No full textThe passivity and passivity breakdown of Fe3Al–Si and Fe3Al–Ge iron aluminides were studied in borate
buffer solution (pH 8.4) in the absence and presence of 100 mM KCl, performing potentiodynamic polar-
ization, potentiostatic transients and electrochemical impedance spectroscopy (EIS) measurements com-
plemented with scanning electron microscopy (SEM). In the absence of chloride ions Si and Ge exercise a
beneficial role in the passivating characteristics of Fe3Al intermetallic. Addition of Si or Ge significantly
modifies the electrochemical response of iron aluminide Fe3Al resulting in a more stable passive film.
In the presence of chloride ions all the intermetallic compounds experience localized corrosion (pitting).
However, Si and Ge alloying additions increase the breakdown potential and the extent of passivation
domain, indicating improved resistance to initiation of pitting corrosion. Furthermore, EIS measurements
performed at the breakdown state evidenced higher Rct and lower depression angle values for Fe3Al–Si
and Fe3Al–Ge iron aluminides compared to Fe3Al intermetallic, confirming their better localized corro-
sion behavior. The improved resistance to pitting corrosion results from the enhanced protective function
of passive film due to the presence of Si or Ge that inhibit pit initiation by hindering the adsorption of ClÀ
ions at the metal surface
Effect of copper alloying addition on the electrochemical corrosion behaviour of Fe3Al intermetallic in sulphuric acid solution
No full textThe effect of Cu alloying addition on the corrosion resistance of iron aluminide
Fe3Al has been investigated. In this work, the corrosion behaviour of Fe3Al-5Cu
(at%) alloys has been assessed by open circuit potential, potentiodynamic
polarisation and electrochemical impedance spectroscopy (EIS) measurements
carried out in a 0.5 M H2SO4 solution, without stirring and in contact with the
air. For comparison, the electrochemical tests have also been performed on
Fe3Al intermetallic. The obtained electrochemical results indicate that iron
aluminide Fe3Al-5Cu exhibits superior corrosion resistance as compared to
Fe3Al. This improvement may be ascribed to the formation of a copper-enriched
surface layer which shows higher protective effectiveness than that formed on
Fe3Al intermetallic
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
DETOXIFICATION OF COPPER IN THE CELLS OF THE DIGESTIVE GLAND OF MUSSEL - THE ROLE OF LYSOSOMES AND THIONEINS
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