1,720,963 research outputs found
Thermodynamics of intermetallics through emf measurements under effusion conditions
No full textA general treatment is performed for a complete description of the thermodynamics of galvanic cells PtMe′′, Me′′zF jCaF2s.c./MehMe′k, Me lMe′m,MexFyPt type working under effusion conditions where the vaporization of Me′′ is considered. The treatment has been applied to three Me2Ni17Ni ss systems with Me ≡ Eu, Tb, Ho and Me hMe′k is the solid solution, Niss, produced by the eutectic reaction L ↔ Me2Ni 17s+Niss. From the emf vs T experimental data, ΔfH298θ and Δ fST̄θ have been calculated. The ΔfH298θ values for Tb 2Ni17(s) and Ho2Ni17(s) are, respectively, -16.76±0.06 and -18.8±0.1 kJ/mol atoms. In the same order, the ΔfST̄θ values are -1.27±0.06 and -1.81±0.09 JK-1/ mol atoms, respectively, at T = 1023 and 1085 K. For Eu2Ni17(s), ΔfHT̄θ and Δ fST̄θ are, respectively, -48±4 kJ /mol atoms and 2.0±0.2 JK-1/mol atoms, both the values at T = 910 K. The latter results should be considered unexpected and the reason for this is extensively discussed. © 2003 Elsevier Ltd. All rights reserved
HETEROGENEOUS EQUILIBRIUM BETWEEN YBA2CU3O7-DELTA AND OXYGEN GAS STUDIED BY A KINETIC APPROACH
No full textThe kinetic behaviour of the YBa2CU3O7-delta system has been investigated via a 'T-jump' experiment. This is realized by a displacement of the thermodynamic system from equilibrium by a temperature jump. The subsequent relaxation process is followed via resistivity measurements. Kinetic models have been formulated by assuming the formation of singly and doubly charged oxygen vacancies and according to the kinetic law of mass action. A good agreement between the theoretical model and the experimental data has been achieved in the case of singly charged oxygen vacancies in the temperature range 400-800-degrees-C. At equilibrium the YBa2Cu3O7-delta conductivity is found to be a function of the oxygen partial pressure, P, according to sigma is-proportional-to P(n) with 1/4 < n < 1/2
X-ray, heat excess and 4He in the D/Pd system
No full textThe energy balance between heat excess and He-4 in the gas phase has been found to be reasonably satisfied even if the low levels of He-4 do not give the necessary confidence to state definitely that we are dealing with the fusion of deuterons to give He-4. In the melted cathode, the data of which are reported, no He-4 was found at the achieved sensitivity. X-ray film, positioned at 50 mm from the cell, roughly gave the image of the cathode through spots. Extended considerations have been made to explain this evidence on the basis of the bundle nature of the cathode. From these considerations, the energy of the radiation and the total energy associated to it have been estimated, as 89 keV and 12 kJ, respectively. This value is approximate to 0.5% of the energy measured by calorimetry in the same interval of time. The highest values of energy and excess power are 8.3 MJ and 10 W, respectively. (C) 1997 Elsevier Science S.A
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
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
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