1,720,957 research outputs found
Optimization of mechanical behavior of PEKK/carbon fibers structural composites by PEKK oligomers sizing
No full textL'objectif de cette recherche est la conception et l'analyse d'un ensimage pour composites structuraux PEKK/Fibres de carbone (FC) continues. Les oligomères de PEKK (oPEKK) ont été synthétisés en laboratoire pour définir les caractéristiques physico-chimiques permettant leur utilisation comme agent d'ensimage. A partir de ce cahier des charges, un oligomère " pilote " a pu être synthétisé afin de mener des études sur la formulation de l'ensimage. A partir d'une étude quantitative de relation structure-propriété (QSPR) et des réseaux de neurone artificiels (ANN), le développement et l'optimisation d'une formulation d'ensimage " solvantfree " ont été réalisés Le dépôt de cet ensimage a été effectué selon deux protocoles : nous avons ainsi réalisé un " ensimage laboratoire " et " ensimage sur pilote ". Les performances mécaniques des composites PEKK/FC ensimés oPEKK ont été étudiées par analyse mécanique dynamique (AMD) ; quel que soit le protocole, l'ensimage optimise les performances mécaniques de manière significative. Il est intéressant de souligner que l'" ensimage sur pilote " est plus efficace que l'" ensimage laboratoire ". Outre, l'intérêt de l'ensimage au niveau de la mise en œuvre des composites, le transfert de contraintes fibre/ matrice est optimisé ce qui se traduit par une augmentation des modules mécaniques conservatif et dissipatif.The objective of this research is to design and analyze a sizing for PEKK / continuous carbon fiber (CF) structural composites. PEKK oligomers (oPEKK) were synthesized in the laboratory to define the physicochemical characteristics allowing their use as a sizing agent. From these specifications, a "pilot" oligomer was synthesized in order to carry out studies on the sizing formulation. From a study of quantitative structure-property relationship (QSPR) and artificial neural networks (ANN), the development and optimization of a "solvent-free" sizing formulation was performed. The deposit of this sizing was achieved according to two protocols: we thus produced a "laboratory sizing" and "pilot sizing". Mechanical performances of PEKK / CF without and with oPEKK sizing composites were studied by dynamic mechanical analysis (DMA). Whatever the protocol is, the sizing optimizes the mechanical performances significantly. It is interesting to note that "pilot sizing" is more efficient than "laboratory sizing". Besides the advantage of sizing for fiber placement in composite processing, the fiber / matrix stress transfer is optimized. Then, it results in an increase of both storage and loss modulus
Optimisation du comportement mécanique de composites structuraux PEKK/Fibres de carbone par ensimage oligomères de PEKK
Get PDFL'objectif de cette recherche est la conception et l'analyse d'un ensimage pour composites structuraux PEKK/Fibres de carbone (FC) continues. Les oligomères de PEKK (oPEKK) ont
été synthétisés en laboratoire pour définir les caractéristiques physico-chimiques permettant leur utilisation comme agent d'ensimage. A partir de ce cahier des charges, un
oligomère " pilote " a pu être synthétisé afin de mener des études sur la formulation de l'ensimage. A partir d'une étude quantitative de relation structure-propriété (QSPR) et
des réseaux de neurone artificiels (ANN), le développement et l'optimisation d'une formulation d'ensimage " solvantfree " ont été réalisés Le dépôt de cet ensimage a été
effectué selon deux protocoles : nous avons ainsi réalisé un " ensimage laboratoire " et " ensimage sur pilote ". Les performances mécaniques des composites PEKK/FC ensimés
oPEKK ont été étudiées par analyse mécanique dynamique (AMD) ; quel que soit le protocole, l'ensimage optimise les performances mécaniques de manière significative. Il est
intéressant de souligner que l'" ensimage sur pilote " est plus efficace que l'" ensimage laboratoire ". Outre, l'intérêt de l'ensimage au niveau de la mise en œuvre des
composites, le transfert de contraintes fibre/ matrice est optimisé ce qui se traduit par une augmentation des modules mécaniques conservatif et dissipatif.The objective of this research is to design and analyze a sizing for PEKK / continuous carbon fiber (CF) structural composites. PEKK oligomers (oPEKK) were synthesized in the
laboratory to define the physicochemical characteristics allowing their use as a sizing agent. From these specifications, a "pilot" oligomer was synthesized in order to carry
out studies on the sizing formulation. From a study of quantitative structure-property relationship (QSPR) and artificial neural networks (ANN), the development and optimization
of a "solvent-free" sizing formulation was performed. The deposit of this sizing was achieved according to two protocols: we thus produced a "laboratory sizing" and "pilot
sizing". Mechanical performances of PEKK / CF without and with oPEKK sizing composites were studied by dynamic mechanical analysis (DMA). Whatever the protocol is, the sizing
optimizes the mechanical performances significantly. It is interesting to note that "pilot sizing" is more efficient than "laboratory sizing". Besides the advantage of sizing
for fiber placement in composite processing, the fiber / matrix stress transfer is optimized. Then, it results in an increase of both storage and loss modulus
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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