1,720,954 research outputs found
Chemical Machining of Copper-Based Aerospace Alloys Produced Through Additive Manufacturing: A Preliminary Approach to Improve Surface Quality
No full textAdditive Manufacturing (AM) is transforming the production of high-performance components, particularly in the aerospace sector. However, the surface quality of AM products often does not meet industry standards, necessitating additional treatments. Chemical machining processes are especially advantageous for preserving the intricate geometries of AM parts, yet their application can be challenging for certain metals due to the presence of alloying elements. The objective of this study is to evaluate the enhancement of surface properties, with a focus on roughness reduction, in GRCop-42 components fabricated via powder bed fusion technology, through the application of chemical machining treatments. Two distinct chemical machining solutions were considered: one formulated with ferric chloride and the other composed of a mixture of sulfuric and nitric acids. Furthermore, two experimental setups were implemented to assess the efficacy of ultrasound assistance during the chemical machining process. The results demonstrated that both chemical solutions effectively removed surface material, with the integration of ultrasound significantly accelerating the process. Surface roughness was reduced by up to 13 pct and the steepness of the surfaces was markedly decreased, achieving a nearly uniform finish. However, the utilization of ultrasound with the lower viscosity solution resulted in cavitation erosion, which created undesirable cavities on the surface
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
Evolution of Unstable Skin-Stringer Debonding Propagation in Composite Aircraft Structures: Implications on Damage Tolerant Design
No full textInterlaminar damages are a key challenge that limits the widespread use of composite materials in aircraft primary structural parts. Although years have already passed since the introduction of these materials, unstable propagation of delamination damage is still the base for evaluating the durability and reliability of structures made of composite laminates. In this paper, the unsteady and sudden propagation of skin-stringer debonding in a typical aircraft composite panel is investigated. Experimental tests and advanced finite element simulations have been performed to assess the evolution of debonding under compressive loading conditions. Fibre-reinforced composite panels, reinforced with a single T-shape stringer and characterized by artificial debonding at the interface between skin and stringer, have been experimentally tested and numerically analysed. The test output has revealed unstable growth of the debonding, with implications for the structural stability of the panels. The experimental results have been then compared with numerical simulations performed by using the Virtual Crack Closure Technique based SMart-time XB numerical procedure and excellent correlation have been found in terms of strain measurements against compressive load
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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