1,720,956 research outputs found
Simulation numérique du comportement macroscopique des matériaux hétérogènes à matrice élastique et inclusion élastoplastique pour l'utilisation en construction aéronautique
No full text115 p. : ill. ; 30 cmLes matériaux composites de haute performance commencent à prendre une place très importante dans l’industrie aéronautique et particulièrement en structure avion (on atteint 50%), vu leurs avantages en terme de qualité/prix.
Vu la diversification de ces matériaux (plus de 50 000 matériaux), des recherches et des études sont entreprises en se basant sur des expériences réelles afin d’améliorer la conception et l’exploitation de ces matériaux. Des méthodes très performantes se sont développées grâce aux logiciels informatiques qui ont permis de faire des simulations sur la caractérisation et l’étude du comportement de ces matériaux. Ce travail consiste à étudier le comportement macroscopique des matériaux hétérogènes à matrice élastique, avec inclusion élastoplastique, appliqués à l’aéronautique. Une étude comparative avec d’autre résines (INJ et STR), avec les mêmes renforts en fibre de carbone et en fibre de verre, a
été réalisée. Une autre étude d’un cas particulier en réparation aéronautique nommé réparation par patch a été faite, suite aux travaux réalisés pour un matériau quelconque avec matrice élastique et renfort élastoplastique. Comparativement au travail d’homogénéisation effectué à une échelle microscopique, et réalisé avec des stations de calcul, notre travail est plus orienté vers l’expérimental dont une comparaison avec des résultats de simulation obtenus par le logiciel exploité en mécanique ANSYS. Des observation au microscope électronique à balayage (MEB) ont été aussi réalisés pour détecter les
irrégularités de nos échantillons. Des techniques de contrôle non destructifs employées en aéronautique sont détaillées pendant l’étude de la méthode de réparation selon l’utilisation et le type de composite ; la technique utilisée est celle de contrôle à ultrasons qui nous permettra d’avoir des informations sur les paramètres d’élasticit
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
Experimental study of environmentally Friendly composite materials Behavior in aeronautical applications
No full textThis study is a part of a work in progress on the mechanical
behavior of laminate in various modified epoxy matrices. we begin
with a laminate six folds with fiberglass taffeta, and epoxy matrix
cross linked by aliphatic Amine called MEDAPOXY STR, this resin is
in the form of a kit of two elements ,a monomer and a hardener with
the report weight of 0,67%. The treatment of the results shows that the
reticulation of monomer by this Amine is incomplete what provokes a
plastic domain on the mechanical behavior of the matrix, concerning
composites made from these elements, the results show that the elastic
domain is dependent on the elasticity of fibers used and not on the
matrix. The control by ultrasound can be considered as another way
to measure and follow-up of the parameters elasticity of the elaborate
laminat
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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