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The anodic dissolution of nickel and molybdenum in methanol and water-methanol mixtures
No full textSome experimental results concerning the anodic behaviour of Nickel and Molybdenum in methanol and water-methanol mixtures are reported. The protective oxide of Ni is destabilized, even in neutral solutions, by the presence of small quantities of chlorides (ca. 3.5-170 ppm). In the case of Mo, the influence of acidity, water content and chloride concentration is negligible, at least in the intermediate region of anodic potentials which is the most interesting for practical applications. © 1980
Effect of water content on the corrosion behaviour of Ni in methanol (MeOH) solutions
No full textThe effect of water content on the corrosion behaviour of nickel in methanolic solutions have been investigated tracing the potentiostatic curves at room temperature in a standard electrochemical cell. Preliminary results reported in this communication, shown that the electrochemical behaviour of Ni in MeOH is strongly influenced by the water content of the solution and that traces of water (of the order of 0.5%) are able to guarantee the passivity of nickel. © 1981
The passivity of ferritic (Fe-18% Cr) stainless steel in methanolic solutions
No full textAn experimental study to define the active-passive behaviour of a ferritic (Fe-18%Cr) stainless steel in methanol, as a function of the concentration of Cl- ions and acidity level, is reported. The addition of water was considered to be an inhibitor capable of reinforcing the passive film of stainless steel. The effects of acidity and of the addition of water on the anodic and cathodic behaviour of Ni, Mo, Fe and The Fe-18%Cr alloy are reported. © 1981 Chapman and Hall Ltd
Solid supported chiral auxiliaries in asymmetric synthesis. Part 2: Catalysis of 1,3-dipolar cycloadditions by Mg(II) cation
No full text1,3-Dipolar cycloadditions of supported Evans' chiral auxiliary with nitrile oxides and nitrones in the presence of Mg(II) cation as catalyst were evaluated. The presence of acetonitrile as co-solvent was found to be fundamental for the Lewis acid catalysis on solid-phase. The regio- and stereochemical outcome of nitrile oxide cycloadditions is influenced by nearly stoichiometric quantities of the cation, whilst catalytic amounts of Mg(II) influence both the reactivity and the stereoselectivity of the nitrone cycloadditions. The results obtained support a reaction mechanism involving the coordination of the Mg(II) to the dicarbonyl fragment of the chiral auxiliary
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
(4S)-p-Hydroxybenzyl-1,3-oxazolidin-2-one as a solid-supported chiral auxiliary in asymmetric 1,3-dipolar cycloadditions
No full textEvans' chiral auxiliary was grafted onto both Merrifield and Wang resins and, after functionalisation, they were used as chiral dipolarophiles in a 1,3-dipolar cycloaddition involving both a nitrile oxide and a nitrone. The cycloadducts were cleaved and analysed by chiral HPLC: the recovered supported chiral oxazolidinone was functionalised and reused in further cycloadditions. The stereochemical results as well as the possibility of recycling the chiral linker supports the applicability of solid-supported chiral auxiliaries. (C) 2000 Elsevier Science Ltd
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
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