1,720,953 research outputs found
Effet des paramètres de fabrication additive et de post-traitement sur les performances de l'acier maraging : étude de sensibilité, exploration, modélisation et optimisation de la technique de la fusion laser sélective et des post-traitements appliqués à l'acier maraging (C300)
Get PDFRÉSUMÉ : La fusion sélective laser (SLM) est un procédé prometteur qui est en voie de développement grâce aux innovations techniques et aux travaux de recherches actives qui ont vu le jour dans les récentes années. L'acier maraging (C300), qui appartient à la gamme des métaux qui peuvent être mis en œuvre par la fabrication additive grâce à sa bonne imprimabilité, a été utilisé dans différents domaines, tels que l'outillage, le moulage, l'aérospatial, et l'industrie automobile, en raison de ses hautes caractéristiques mécaniques. Cependant, certaines limitations sont toujours là, y compris le coût de production, la nécessité de post-traitement des pièces telles que construites et les effets non encore maîtrisés des différents paramètres du processus et des caractéristiques de post-traitement thermique. C'est pourquoi la fusion sélective laser des aciers maraging fait toujours un sujet intéressant de recherche et développement. Néanmoins, beaucoup reste encore à faire pour perfectionner l'utilisation de la technique SLM pour la production des pièces complexes à haute résistance afin d'avoir un procédé rentable et efficace. Dans cette mémoire, l'influence de plusieurs traitements thermiques sur les différentes propriétés mécaniques des SLM-acier maraging (C300) ainsi que la sensibilité des ces propriétés mécaniques aux paramètres du procédé, spécialement la puissance laser, la vitesse de balayage, l'espace d'hachurage et la densité d'énergie laser, ont été examinées expérimentalement. À cet effet, plusieurs séries d'expériences ont été faites dans le cadre de la recherche en faisant varier les paramètres de SLM et de traitements thermiques pour disposer de données satisfaisantes pour pousser l'analyse en profondeur. Les paramètres de processus SLM et de traitement thermique ont été mesurés pour leur effet sur la formation de défauts, la microstructure et les propriétés mécaniques. Des outils statistiques tels que l'ANOVA sont utilisés pour cela, précédés d'une planification d'expérience faisant appel à la méthode Taguchi et un design factoriel complet. L'optimisation est faite à l'aide d'outils numériques qui sont des méthodes itératives et algorithmiques aidant à trouver les valeurs optimales. Les résultats de l'étude ont montré l'efficacité de cette approche en mettant en avant la sensibilité et l'apport des traitements thermiques en termes des performances mécaniques. -- Mot(s) clé(s) en français : fusion laser sélective, paramètres de procédé, acier maraging, traitement thermique, propriétés mécaniques, optimisation, Taguchi, ANOVA. --
ABSTRACT : Selective laser fusion (SLM) is a promising process, which is under development thanks to the technical innovations and the active research works which have emerged in recent years. Maraging steel (C300), which belongs to the range of metals affected by additive manufacturing thanks to its good printability, has been used in different fields, such as tooling, casting, aerospace, and automotive, due to its high mechanical characteristics. However, some limitations are still there, including the cost of production, the necessity of post-treatment of as-built parts, and the unchecked effects of various process parameters and heat post-treatment characteristics. Therefore, the selective laser melting of maraging steels is still a curious subject of research and development. However, much remains to be done to perfect the use of the SLM technique to produce complex high-strength parts, in order to have a cost-effective and efficient process. In this paper, the influence of several thermal routes on the different mechanical properties of SLM-steel maraging (C300) as well as the sensitivity of these mechanical properties to process parameters, especially laser power, scanning speed, space hatching, and laser energy density, have been investigated experimentally. To this end, several series of experiments have been carried out within the framework of the research by varying the parameters of SLM and heat treatments to obtain satisfactory data for further analysis in depth. SLM process and heat treatment parameters were measured for their effect on defect formation, microstructure, and mechanical properties. Statistical tools such as ANOVA are used for this preceded by an experiment planning using the Taguchi method and a full-factorial design. The optimization is done using numerical tools which are iterative and algorithmic methods helping to find the optimal values. The results of the study showed the effectiveness of this approach by highlighting the sensitivity and contribution of heat treatments in terms of mechanical performance. -- Mot(s) clé(s) en anglais : selective laser melting, process parameters, maraging steel, heat treatment, mechanical properties, optimization, Taguchi, ANOVA
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
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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