1,720,964 research outputs found
Evaluation and impact of the degree of impregnation of uncured out-of-autoclave prepreg
No full textOut-of-autoclave prepreg contains partially impregnated fibre tows which act as paths for gas evacuation. The degree of impregnation of resin into the dry fibre bed is a quantitative measure of the size of these dry fibre pathways and can affect part quality and rejection rates. There is no well-defined and accurate standard method to measure this quantity. The current state-of-the-art is to manufacture discriminator panels, which are panels containing complex features such as tight radius corners, internal ply drop-offs, sandwich regions, etc. to determine the producability of specific components by specific material. That is, it is an empirical method used to determine if the initial properties of the prepreg fall within certain boundaries. This technique is time consuming and does not necessarily account for variations within specific rolls of material. The aim of this thesis is twofold: examine different techniques to measure the degree of impregnation of out-of-autoclave prepreg and perform an experimental investigation into the impact of degree of impregnation on the breathability of the material.Firstly, different methods to quantitatively measure the degree of impregnation of out-of-autoclave prepreg are examined. Three methods are compared: X-ray computed tomography, the water uptake test, and active infrared thermography. The first method serves as a baseline for accuracy but is expensive both in terms of cost and time. The second method is characterized by its simplicity but is destructive and only gives local information over a small sample area. The latter method shows promise as a quick, non-destructive evaluation technique. A further investigation into active infrared thermography highlights some limitations of the technique with regards to its implementations in an industrial setting.Secondly, the impact of degree of impregnation on the gas transport phenomena in composite materials is evaluated by manufacturing single skin sandwich panels in an instrumented fixture with a simple design of experiments. Under room temperature conditions, as the degree of impregnation increases, the material's ability to transport gas is reduced, resulting in higher core pressure. However, at elevated temperatures, this impact is lessened and final laminate quality in all panels manufactured is similar.Both material and process variability is inherent in composite materials. Currently, it is important to use robust material systems and process cycles; however, through the use of non-destructive material inspection it would be possible to measure this variability and mitigate any problems caused by it through process modification or material rejection.Les pré-imprégnés hors autoclave comportent des régions sèches qui permettent l'évacuation des gaz. Le degré d'imprégnation de la résine dans les fibres sèches est une mesure quantitative de la taille de ces régions et peut affecter la qualité des pièces et le taux de rejet. Il n'existe pas de méthode définie et précise pour mesurer cette quantité. La pratique actuelle consiste à fabriquer des panneaux discriminants, qui contiennent des éléments complexes tels que des rayons serrés, des fins de plis internes, des zones renforcées par une âme, etc. pour déterminer la faisabilité de ces composantes spécifiques. Autrement dit, il s'agit d'une méthode empirique utilisée pour déterminer si les propriétés initiales du pré-imprégné sont conformes dans les limites de la pièce à fabriquer. Cette technique prend beaucoup de temps et ne tient pas nécessairement compte des variations à l'intérieur des rouleaux de matière. L'objectif de cette thèse est double: examiner différentes techniques pour mesurer le degré d'imprégnation de pré-imprégnés hors autoclave et effectuer une étude expérimentale sur l'influence du niveau d'imprégnation sur la respirabilité du matériau.Premièrement, différentes méthodes de mesure quantitative du degré d'imprégnation de pré-imprégnés hors autoclave sont examinées. Trois méthodes sont comparées: la tomodensitométrie par rayon X, le test d'absorption d'eau, et la thermographie infrarouge. La première méthode sert de base de référence pour la précision mais elle se révèle coûteuse en termes de coût et de temps. La deuxième méthode se caractérise par sa simplicité, mais est destructive et se limite à de petites surfaces de l'échantillon, fournissant uniquement une information locale. La dernière méthode est rapide, non destructive et prometteuse comme technique d'évaluation. L'étude plus approfondie de la thermographie infrarouge met en évidence certaines limites de cette technique concernant son implémentation dans un milieu industriel.Deuxièmement, l'influence du degré d'imprégnation sur les phénomènes de transport de gaz dans les matériaux composites est évaluée par la fabrication de panneaux sandwich dans un moule instrumenté avec un simple plan d'expériences. Dans des conditions de température ambiante, lorsque le degré d'imprégnation augmente, la capacité du matériau à transférer des gaz est réduite, entraînant une pression de l'âme à nid d'abeille élevée. Cependant, à des températures élevées, cet effet est réduit et la qualité finale des peaux de tous les panneaux fabriqués est similaire.La variabilité des matériaux et des processus est inhérent dans les matériaux composites. Actuellement, il est important d'utiliser des systèmes de matériaux et cycles de procédés robustes; toutefois, grâce à l'utilisation d'inspection non destructive, il serait possible de mesurer cette variabilité et d'atténuer les problèmes qu'il cause par des modifications du procédé ou rejet des matériaux
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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