1,720,965 research outputs found
Développement de verres métalliques à base de titane pour des applications dentaires à travers une stratégie de conception innovante, l'optimisation du procédé et la fonctionnalisation de la surface
No full textLes implants dentaires actuels sont majoritairement fabriqués en titane commercialement pur (cp-Ti) ou en Ti-6Al-4V (grade 23). Ces matériaux présentent d’excellents résultats cliniques sur des suivis à court et long termes. Toutefois, les alliages titane ont atteint un plateau en termes de propriétés mécaniques ce qui limite la miniaturisation des composants implantaires dentaires (implants dentaires, piliers et vis connectique). Des matériaux alternatifs avec une biocompatibilité au moins équivalente, une bonne résistance à la corrosion et une facilité de mise en œuvre doivent être étudiés pour concevoir des implants dentaires moins invasifs. Les verres métalliques à base de titane (Ti-based BMGs) sont des matériaux potentiels pour la réduction de la taille des composants implantaires. Grâce à leur structure amorphe (absence d’ordre atomique à grande distance), ces matériaux possèdent une très bonne biocompatibilité, peuvent être thermoformés, atteignent une déformation élastique de 2% ainsi qu’une limite d’élasticité de près de 2000 MPa. Bien que leur capacité à se déformer plastiquement soit limitée, les verres métalliques à base de titane, et en particulier la nuance Ti40Zr10Cu36Pd14, a démontré des résultats encourageant dans des applications implantaires dentaires durant la phase de prototypage. Cependant, l’utilisation des verres métalliques à base de titane est restreinte par deux aspects. Premièrement, la résistance à la corrosion de ces alliages est limitée par la présence du cuivre qui engendre la corrosion par piqûres en milieu chloré. Ainsi, des stratégies réduisant la teneur en cuivre doivent être envisagés afin de prévenir son influence délétère sur le comportement en corrosion. Deuxièmement, la capacité de ces alliages à former une structure amorphe (GFA) est insuffisante pour empêcher totalement la cristallisation lors du refroidissement. Les hétérogénéités cristallines peuvent causer une rupture prématurée en tension et leur formation reste insuffisamment décrite dans la littérature. Cette thèse de doctorat aborde à la fois des questions scientifiques et industrielles en rapport avec les verres métalliques à base de titane et s’articule autour de trois axes de recherche : (i) la conception d’alliages, (ii) les procédés de fabrications et (iii) la fonctionnalisation de surface. En premier lieu, des compositions alternatives amoindries en cuivres sont identifiées par apprentissage automatique. Ensuite, la formation des hétérogénéités crystallines dans la nuance Ti40Zr10Cu36Pd14 est étudiée et mise en lien avec les procédés de fabrication. Enfin, deux modifications de surface sont proposées pour améliorer la résistance à la corrosion de la composition Ti40Zr10Cu36Pd14.Current dental implants are predominantly made of commercially pure titanium (cp-Ti) and Ti-6Al-4V alloys. These materials demonstrate excellent clinical outcomes over short- and long-term follow-ups. However, crystalline Ti-alloys have reached a plateau in terms of mechanical properties, hindering further downsizing of dental implant components (e.g. dental implants, abutments and connecting screws). Alternative materials with higher mechanical strength, and at least equivalent biocompatibility, corrosion resistance and processability must be explored to design less invasive load-bearing implantable devices. Ti-based bulk metallic glasses (Ti-based BMGs) are attractive materials to downsize dental implant components. Due to their amorphous structure (i.e. absence of long atomic range order), Ti-based BMGs exhibit excellent biocompatibility, thermoplastic forming ability, high elastic strain limit (εl ≈ 2%) along with outstanding mechanical strength (yield strength σy ≈ 2000 MPa). Despite their relatively ‘brittle’ behaviour under plastic deformation, Ti-based BMGs, particularly, the Ti40Zr10Cu36Pd14 composition, has shown encouraging results for use in dental application during the prototyping stage. However, the use of Ti-based BMGs is limited by two aspects. Firstly, the corrosion resistance of Ti-based BMGs is impaired due to the high content of copper in the alloys, which can trigger pitting corrosion in chloride environments. Therefore, strategies to remove copper or mitigate its influence on corrosion resistance have to be considered. Secondly, the glass forming ability (GFA) of Ti-based BMGs is insufficient to consistently prevent crystallisation upon cooling. Crystalline heterogeneities may cause premature failure under tensile loading and their formation remains incompletely described in the literature. This PhD addresses scientific queries and industrial challenges related to Ti-based BMGs through three research paths involving (i) materials design, (ii) materials processing and (iii) surface functionalisation. At first, alternative compositions with reduced amount of copper are explored by mean of a machine learning (ML) strategy. Then, the formation of crystalline heterogeneities in Ti40Zr10Cu36Pd14 alloys is investigated in relation with the processing techniques. Lastly, two surface modifications are proposed to improve the corrosion resistance of Ti40Zr10Cu36Pd14
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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