1,720,954 research outputs found
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
Study on Micro-Drilling Characteristics of a Ni Based Superalloy
No full textAccomplishment of good dimensional accuracy in micro drilling of Ni-based superalloys has always been a challenge. Hence, ample research, especially on the micro machinability of the superalloy, is required for the low cost, large scale utilisation of the material in different industrial fields. At the very outset, the FEM simulation of micro-drilling of Incoloy 825 using a 0.4 mm drill made up of cemented carbide (WC-Co) was carried out. The aim of this initial phase of work was to explore fundamental insights into various micro-drilling characteristics of the same workpiece material. The effect of feed was simulated on various cutting forces, dynamic fluctuations and specific cutting energy under dry environment. Thrust force and radial forces along with their dynamic components obtained during experimentation were in close agreement with the results of simulation with a deviation in the range of 7 to 8 %. Moreover, efforts were also made to experimentally study the various features of the micro holes including oversize error and circumferential deformation layer under the same condition. A comparative study of micro-drilling of Incoloy 825 with pilot and without prior pilot under minimum quantity lubrication (MQL) condition was carried out to understand the effect of pilot hole. The next phase of study sought to explore the mechanism of physical vapour deposition (PVD)-based TiAlN coating in micro-drilling of Ni-based superalloy. Results indicated that increase in edge radius due to coating hindered the performance of coated micro-drill while machining under very low feed (1 μm/rev). This was attributed to ‗size effect‘. However, elevation of feed, cutting speed and also machining duration (number of holes drilled) was found to be effective for TiAlN coated micro-drill. Furthermore, a comparative study of different cooling techniques was undertaken to investigate their influences on thrust force, tool wear, oversize error and circumferential deformation layer under constant cutting parameters (spindle speed of 20000 rpm and feed of 2.5 μm/rev). The experimental results demonstrated remarkable improvement in micro-machining characteristics under MQL which caused significant reduction in thrust force of around 8 % and average flank wear of 60 % compared to flood cooling. Therefore, MQL may successfully replace conventional flood cooling process during micro-drilling difficult-to-cut materials like Ni-based superalloys. The final phase of experiment aimed at investigating the effects of CrAlN and TiAlN coatings deposited using high power impulse magnetron sputtering (HiPIMS). Influence of feed which plays a major role on size effect was studied for the uncoated and coated micro-drills in terms of thrust force along with its bandwidth, oversize error and average flank wear. Particular emphasis was placed on the exploration of the mechanism of wear of the coated micro-drills in comparison with their uncoated counterpart. HiPIMS coated micro-drills were successful in mitigating thrust force, bandwidth and rate of progression of wear. However, TiAlN consistently outperformed the CrAlN coating in micro drilling of Incoloy 825 owing to the superior hardness, coating adhesion and chemical inertness of TiAlN towards Ni based superalloys
Effect of Cutting Parameters on Micro Drilling Characteristics of Incoloy 825
Get PDFThe study focuses on the micro drilling of Incoloy 825 alloy under flood cutting condition. Micro drilling on nickel based superalloy is very challenging process due to the material properties, operating conditions, low thermal conductivity and high quality requirements. Due to low thermal conductivity of material heat is concentrated near tool tip and unable to dissipate for which tool wear occurs. The current study described the machinability of Incoloy 825 in micro drilling operation and also the effect of spindle rpm and feed rate on thrust force, torque, radial component force, tangential component forces, oversize diameter and white layer thickness. The current study investigates the influence of micro drilling parameters on surface profile and circumferential damage of micro holes (in terms of damaged layer thickness). ANSYS simulation was carried out to theoretically determine and evaluated necessary data like equivalent stress and deformation. Statistical analysis was also carried out to develop predictive models for various output characteristics
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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