1,720,955 research outputs found
Phase evolution in mechanical alloying and spark plasma sintering of AlxCoCrCuFeNi HEAs
No full textAlxCoCrCuFeNi high-entropy alloys were synthesised through mechanical alloying and spark plasma sintering. Different alloys were produced by varying the aluminium content (x = 0.5, 1.5, 2.5 and 4). The influences of the milling duration on the evolution of microstructure, constituent phases and morphology were studied. Increasing milling time resulted in grain refinement and higher solid solution homogenisation characterised by a high internal strain. As a consequence of aluminium addition, the microstructure of materials evolved from face centered cubic (FCC) and body centered cubic (BCC) phases to FCC, BCC and ordered BCC phases. Both mechanical alloying and SPS conditions as well as aluminium content led to grain refinement and variations of mechanical properties. In particular, hardness increased with increasing aluminium content. The aluminium percentage and the evolution of consequent phases are responsible for the microstructural stability at high temperatures. In addition, with Al content increase, the further synergy of strength and ductility along with a more pronounced strain hardening was obtained
Crystal structure evolution in mehcanical alloying and spark plasma sintering of AlxCoCrCuFeNi HEAs
No full textAl x CoCrCuFeNi high entropy alloys were synthesised through mechanical alloying and spark plasma sintering. Different alloys were produced by varying the aluminium content (x = 0.5, 1.5, 2.5 and 4). The influence of the milling duration on the evolution of microstructure, constituent phases and morphology was studied. Milling time increasing resulted in grain refinement and higher solid solution homogenisation characterised by a high internal strain. As a consequence of aluminium addition, the materials’ microstructure evolved from FCC and BCC phases to FCC, BCC and ordered BCC phases. Both mechanical alloying and SPS conditions as well as aluminium content let to grain refinement and mechanical properties variations. In particular, hardness increased with increasing the aluminium content. The aluminium percentage and the consequent phases evolution is responsible for the microstructural stability at high temperatures
Friction stir spot welding of TiO2 nanoparticle-reinforced interstitial free steel
No full textThe purpose of the current study was to investigate the effect of different content of TiO2 nanoparticles and FSSW parameter such as tool rotational speed on microstructure and mechanical properties of IF steel FSSW joints. FSSW joints were realized by adding 0.45, 1.14, 2 wt% of TiO2nanoparticles to IF steel. Optical microscopy and scanning electron microscopy and energy dispersive spectroscopy studied along with the results of microhardness measurements and tensile shear analyses. The obtained results showed that the optimal welding conditions were a tool rotational speed of 1120 rpm and a dwell time of 9 s. Microstructural observations demonstrated a good dispersion of TiO2 reinforcements in the steel matrix. TiO2 nanoparticles addition led to a remarkable increase in the mechanical properties of the produced welds. This was attributed to the fine grain size obtained thanks to the ceramic particles addition. The hardness and ultimate load of joints produced by TiO2 amount of 1.14 wt% are optimum welding conditions for fabrication of the best quality of welds which have attributed to the uniform dispersion of TiO2 nanoparticles in the weld regions. For higher than 1.14 wt% content of TiO2, nanoparticles agglomeration occurred, this resulted in the decrease in strength and ductility
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
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