1,721,073 research outputs found
Hydrogen sorption kinetics of magnesium hydride enhanced by the addition of Zr8Ni21 alloy
No full textHydrogen absorption and desorption kinetics, and thermodynamics of MgH 2 ball milled with addition of the Zr 8Ni 21 alloy have been studied. Different additive amounts were used from 3 to 12.5 wt%. The highest reversible capacity of 6.5 wt% of hydrogen was found for the samples with 3 and 5 wt% of additive. The best reaction kinetics was found with 10 wt% of additive: 5.9 wt% H 2 was desorbed in 4 min at 300 °C and 0.1 bar of hydrogen pressure. Regardless of the different storage capacities, all the samples were almost fully hydrided in 1 min using a hydrogen pressure of 10 bar at 250 and 300 °C. The enthalpy of formation of magnesium hydride was not affected by the presence of the additive.Fil: Pighin, Santiago Alberto. Università di Padova; Italia. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Capurso, Giovanni. Universita Di Padova. Dept.di Ingeniería Meccanica; ItaliaFil: Lo Russo, Sergio. Università di Padova; ItaliaFil: Peretti Hollemaert, Hernán Américo. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada; Argentin
Problemi di Fisica Generale Meccanica - Termodinamica
No full textLibro di esercizi di meccanica e termodinamica per studenti di Ingegneri
Effects of surface and bulk transverse fields on the critical behaviour of ferromagnetic films
No full textThe influence of surface and bulk transverse fields on the critical behaviour of ferromagnetic Ising films is studied by using effective field theory based on a single-site cluster method. Surface exchange enhancement is considered and a critical value is obtained. The,dependence of the critical uniform transverse field on the film thickness, the phase diagrams in the fields, the critical surface transverse field versus the bulk one, and the exchange coupling ratio is presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Ferromagnetic transitions of a spin-one Ising film in a surface and bulk transverse fields
No full textUsing the effective field theory method, we have calculated the Curie temperature of a spin-one Ising ferromagnetic film in a surface and bulk transverse fields. Numerical calculations give phase diagrams under various parameters. Surface exchange enhancement is considered. The dependence of the critical transverse field on film thickness, and phase diagrams in the fields, critical surface transverse field versus the bulk one are presented
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