1,720,962 research outputs found
The need for online microstructural image acquisition for tribological charecterisation in rolling/sliding contacts
No full textConsidering their tribological advantage, rolling/sliding contacts like gears, cams and rollers have adopted polymer-metal pairs in several engineering and domestic applications (copy machine, toys, pumps, etc.). The tribological behaviour of these applications is generally studied using real components or by standardized tribotests (ASTM). Although closer to the real application, investigations using real components are less effective because of the dynamicity involved in transfer layer, wear process, micro and macro slip characteristics and also due to the complexity in the contact geometry. In the current research, a twin-disc model representing the Hertzian line contact replicates the micro-slip whereas the macro-slip of the tribological system is achieved using different slip ratios. Efforts are made for microstructural characteristic through online imaging of contact surface to explore interaction between the mating surface and the dynamic behavior from transfer layer deposition. A computer vision system was developed for acquiring online micrographs of contact surface where a high-speed camera in concurrence with a microscope is used. Wear tests were conducted using polymer-metal pairs for offline and online investigations. Micrographs of the composite contact surface were acquired online at 7000 fps – 35000 fps. Transition of wear mechanisms observed during the course of wear elucidates the interaction level at different stages of wear. From the view point of wear mechanism a clear distinction between run-in (ploughing) and steady state (adhesion and plastic deformation) was observed. The online micrograph of contact surface at different intervals validates the back transfer of polymer to the parent material. The unsteady stage is dominated by abrasion on the other hand, as the wear proceeds a transition to adhesion occurs. The initially unfilled (rough) steel surface without transfer layers gains advantage from the asperity geometry to plough the polymer surface. However, after gaining transfer layer in the steel surface, adhesion becomes the dominant mechanism. Finally, a combination of adhesion and abrasion is evident due to the dynamic behavior of transfer layer. Thus online computer vision is an effective tool to characterize the stages of wear process and to understand the mechanism underneath. Understanding the mechanism in a parametric way gives a chance to make necessary alterations for effective design of tribological system. However, the adhesion coefficient between transfer layer and the polymer-steel pairs has to be validated
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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