1,720,956 research outputs found
Effect of Iron content on the microstructure evolution, mechanical properties and wear resistance of FeXCoCrNi high-entropy alloy system produced via MA-SPS
No full textIn the present study, the FexCoCrNi (x = 1, 1.3, 1.6) high entropy alloy (HEA) system was prepared by mechanical alloying (MA) and spark plasma sintering (SPS). The effect of iron content on the microstructure, mechanical properties, thermal behavior, and wear resistance of the FexCoCrNi (x = 1, 1.3, 1.6) HEA system was separately studied. It was found that all 3 alloys showed body-centered cubic (BCC) and face-centered cubic (FCC) solid solutions after 50 h of milling and an increase in the iron content was accompanied by an increase in the fraction of the BCC solid solution. Thermal stability of the FexCoCrNi (x = 1, 1.3, 1.6) HEA system was evaluated in the temperature range of 973–1273 K. The FCC structure was retained even after thermal exposure at 973, 1123, and 1273 K for all 3 alloys. The increase in Fe content led to a decrease in the sigma phase (FeCr or CoCr) formation temperature. The results of mechanical tests indicated that increasing Fe (1–1.6 mol) resulted in enhancement of ultimate tensile strength and hardness from 480 to 560 MPa and 320–400 Vickers, respectively. Wear resistance results demonstrated that the coefficient of friction (COF) and weight loss of this system decreases with increased Fe content. Moreover, the dominant wear mechanism changed from abrasive wear to adhesive wear
Investigation of hardness, wear and magnetic properties of NiCoCrFeZrx HEA prepared through mechanical alloying and spark plasma sintering
No full textIn this work, the effect of the addition of Zirconium on the microstructure, hardness, wear behavior and magnetic properties of NiCoCrFe High Entropy Alloy (HEA) was investigated. The crystal structures and phase evolution of the alloys were characterized using X-Ray Diffraction (XRD). XRD patterns showed the FCC and BCC solid solutions in both alloy powders. To investigate the effect of Zr element on the wear behavior of NiCoCrFe HEA, the alloys, in the form of powder, were compressed using Spark Plasma Sintering (SPS) process, and then, the pin on disk wear test was applied. The results showed that after SPS, BCC/FCC phases of the NiCoCrFeZrx (x = 0) alloy had converted to single-phase FCC (NiCoCrFeZr0.4); however, the mechanical properties and wear behavior of the alloy improved compared to the NiCoCrFe alloy. The micro-hardness and nano-hardness of NiCoCrFe alloy increased from 682 ± 7 and 672 ± 7 Vickers to 828 ± 10 and 845 ± 10 Vickers, respectively. Moreover, the addition of Zr led to significant increasing in wear resistance and decreasing the coefficient of friction. Results of the scanning electron microscope (SEM) equipped with an XRD energy spectrometer (EDS) illustrated that the presence of Zr led to the conversion of the dominant abrasive mechanism to adhesive mechanism. Eventually, the results of the Vibrating Sample Magnetometer (VSM) indicated that the addition of Zr element led to the tendency of NiCoCrFe alloy to be paramagnetic. In this way, the magnetic saturation is reduced by 15%, and the coercive force is increased by 133%
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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