1,721,104 research outputs found
ANODIC DISSOLUTION OF IRON IN ORGANIC SOLVENTS.
No full textWhile the anodic behaviour of Armco iron and the low alloyed steel is strongly influenced by the presence of aggressive ions and by the water content of the solutions, both 304 L and 446 stainless steels show, even in the presence of relatively high concentration of aggressive ions, the formation of stable protective films. The lowest value of the passivation current has been obtained for Armco iron and the low alloyed steel in the base solution (0. 1 M LiClO in organic solvent) at a water content of ca. 0. 5% in all the solvents, the current value increased, either increasing or decreasing the water content. The effect of the presence of chromium seems to be predominant, with respect to water content, on the behaviour of the stainless steels examined
Un metodo veloce ed efficiente per la risoluzione di Equazioni Integrali di Volterra con un WR non stazionario
No full textAn efficient and fast parallel method for Volterra integral equations of Abel type
Full text linkIn this paper we present an efficient and fast parallel waveform relaxation method for Volterra integral equations of Abel type, obtained by reformulating a nonstationary waveform relaxation method for systems of equations with linear coefficient constant kernel. To this aim we consider the Laplace transform of the equation and here we apply the recurrence relation given by the Chebyshev polynomial acceleration for algebraic linear systems. Back in the time domain, we obtain a three term recursion which requires, at each iteration, the evaluation of convolution integrals, where only the Laplace transform of the kernel is known. For this calculation we can use a fast convolution algorithm. Numerical experiments have been done also on problems where it is not possible to use the original nonstationary method, obtaining good results in terms of improvement of the rate of convergence with respect the stationary method
Influence of water content on corrosion of iron and stainless steels in organic solvents
No full textThe anodic behaviour of Armco iron, a low alloy steel, and AISI 304L and 446 stainless steels was evaluated in methanol, dimethylformamide, and acetonitrile as a function of water and aggressive ion content. The observed differences in behaviour in the various environments can be explained by the differing solvating ability of the three solvents. (A
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
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