1,721,274 research outputs found
Vacancy-interface-helium interaction in Zr-Nb multi-layer system: A first-principles study
No full textDriven by our previous experimental findings, we have performed ab-initio simulations to investigate the mechanical properties of and vacancy-interface-helium interaction at Zr-Nb (HCP-BCC) multi-layer composite at Burgers orientation ((0 0 0 2)//(1 1 0) - 〈2 -1 -1 0〉 // 〈1 -1 1〉). HCP-BCC interfaces have not been previously modelled using density functional theory. We present many aspects of this interfacial system such as elastic constants, charge densities and densities of states which, although being crucial in understanding the properties of the materials with interfaces at the atomistic level, are usually ignored by similar works. A thorough analysis of the mechanical properties of Zr-Nb multi-layers has been performed and compared with the behaviour of their constituents in bulk form. The results are promising for applicational purposes as the multi-layers retain most of the mechanical properties of the bulk forms except for the anisotropy index. Furthermore, we present electronic structure analysis which reveals formation of bonding between opposing Zr and Nb atoms and transfer of some net charge at the interface. These results, together with the energetics of the systems, are used to understand the interaction among vacancy, He and the interface which gives insight for foreseeing the behaviour of the system in the presence of He atoms.</p
Helium migration in Zr-Nb multilayers under electric field
No full textThe α particles, which appear during the nuclear reactions and are transformed into He atoms, are often implanted into (or produced in) the structural materials causing deterioration of the mechanical properties. Moreover, they precipitate into high-pressure He bubbles, further decreasing the strength. Metallic alloys with a high density of interfaces and/or grain boundaries can reduce or even heal the defects caused by irradiation; nevertheless, the detrimental effect of He atoms is still a concern and diffusion of He atoms in the vicinity of interfaces is the subject of active research. Here, we present an ab initio study to explore how the electric field influences the diffusion of He atoms in (HCP-BCC) Zr-Nb metallic multilayer composite before they start to agglomerate. Motivated by our previous work, where we showed that He atoms tend to agglomerate into the regions with low electron density, we utilized the shift of electrons inside Zr-Nb multilayer system due to the external field to manipulate the migration of He atoms in a preferred direction. The results indicate that He atoms can be guided along the direction of the field out of the system, especially along [0002] direction in HCP-Zr.<br/
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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