1,720,977 research outputs found
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
Characterization and amorphous phase formation of mechanically alloyed Co60Fe5Ni5Ti25B5 powders
No full textAbstract In this work, the multicomponent Co 60 Fe 5 Ni 5 Ti 25 B 5 (at.%) alloy powders were synthesized from commercially available pure elemental powders by using a mechanical alloying (MA) process under argon gas atmosphere. The changes in structural, morphological, thermal and magnetic properties of the processed powders during MA were examined by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), differential thermal analysis (DTA) and vibrating sample magnetometer (VSM). The results showed that the amorphization occurred after 3.5 h of milling, and the amorphous phase was stable up to 580 °C, where crystallization occurred. The SEM observations indicated that different morphologies were obtained during the MA stages. In addition, the EDX mapping confirmed the uniform distribution of elemental content. Magnetic results indicated that all the samples exhibited soft-ferromagnetic behavior. The evolution of the saturation magnetization (Ms), the coercivity (Hc) and the squareness ratio (Ms/Mr) during milling process were discussed with respect to microstructural changes. The influence of the annealing on magnetic hysteresis was also studied. The Ms, Hc and Ms/Mr values of about 53.4 emu/g, 7.6 Oe and 0.01, respectively was obtained after 7 h of milling
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
Structural evolutions in Ti and TiO2 powders by ball milling and subsequent heat-treatments
No full textIn this study, nanocrystalline Ti and TiO2 powders were synthesized by wet milling of Ti powder within water and reactive milling of Ti powder under oxygen atmosphere, respectively. The wet milling processes were performed at 300 rpm milling speed for different milling durations (6, 12, 24, and 48 h). Subsequent heat-treatments of the as-milled powders were performed at 200-800 degrees C for 1 h in an air atmosphere. Structural characteristics of the as-milled and the heat-treated powders were investigated by X-ray diffraction (XRD). The crystallite size, lattice strain and lattice parameters of the powders were also calculated. It has been realized that during the wet milling process, elemental Ti powder undergoes an hcp to fcc polymorphic transformation, which is related to grain refinement and plastic strain. In addition, TiO2 powders are produced after heat-treatments at 600 and 800 degrees C. Reactive milling of the elemental Ti powder in pressurized oxygen atmosphere leads to nartocrystalline TiO2 powders with an average crystallite size of about 10 nm after 48 h milling time. The subsequent heat-treatments of the asmilled TiO2 powders results in the increase of the crystallite size up to 70-150 nm. In order to understand the thermal behavior of the as-milled powders, thermal analysis (DTA) and thermogravimetric analysis (TGA) were employed. The activation energy of the nanocrystalline TiO2 powders was determined by the Kissinger method is 128 +/- 3 kJ/mol. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved
Characterization and amorphous phase formation of mechanically alloyed Co60Fe5Ni5Ti25B5 powders
No full textIn this work, the multicomponent Co60Fe5Ni5Ti25B5 (at.%) alloy powders were synthesized from commercially available pure elemental powders by using a mechanical alloying (MA) process under argon gas atmosphere. The changes in structural, morphological, thermal and magnetic properties of the processed powders during MA were examined by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), differential thermal analysis (DTA) and vibrating sample magnetometer (VSM). The results showed that the amorphization occurred after 3.5 h of milling, and the amorphous phase was stable up to 580 degrees C, where crystallization occurred. The SEM observations indicated that different morphologies were obtained during the MA stages. In addition, the EDX mapping confirmed the uniform distribution of elemental content. Magnetic results indicated that all the samples exhibited soft-ferromagnetic behavior. The evolution of the saturation magnetization (Ms), the coercivity (Hc) and the squareness ratio (Ms/Mr) during milling process were discussed with respect to microstructural changes. The influence of the annealing on magnetic hysteresis was also studied. The Ms, Hc and Ms/Mr values of about 53.4 emu/g, 7.6 Oe and 0.01, respectively was obtained after 7 h of milling. (C) 2015 Elsevier B.V. All rights reserved
Structural evolutions in Ti and TiO2 powders by ball milling and subsequent heat-treatments
No full textIn this study, nanocrystalline Ti and TiO2 powders were synthesized by wet milling of Ti powder within water and reactive milling of Ti powder under oxygen atmosphere, respectively. The wet milling processes were performed at 300 rpm milling speed for different milling durations (6, 12, 24, and 48 h). Subsequent heat-treatments of the as-milled powders were performed at 200-800 degrees C for 1 h in an air atmosphere. Structural characteristics of the as-milled and the heat-treated powders were investigated by X-ray diffraction (XRD). The crystallite size, lattice strain and lattice parameters of the powders were also calculated. It has been realized that during the wet milling process, elemental Ti powder undergoes an hcp to fcc polymorphic transformation, which is related to grain refinement and plastic strain. In addition, TiO2 powders are produced after heat-treatments at 600 and 800 degrees C. Reactive milling of the elemental Ti powder in pressurized oxygen atmosphere leads to nartocrystalline TiO2 powders with an average crystallite size of about 10 nm after 48 h milling time. The subsequent heat-treatments of the asmilled TiO2 powders results in the increase of the crystallite size up to 70-150 nm. In order to understand the thermal behavior of the as-milled powders, thermal analysis (DTA) and thermogravimetric analysis (TGA) were employed. The activation energy of the nanocrystalline TiO2 powders was determined by the Kissinger method is 128 +/- 3 kJ/mol. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved
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