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Influence de l'orientation cristalline sur les microstructures de déformation et l'adoucissement d'alliages Al-Mn
No full textThe aim of my tesis was to evaluate the influence of crystalline orientation in deformation microstructures and softening (recovery, recrystallization) in cold-rolled Al-Mn alloys.The deformation microstructures of Al–Mn single crystals (namely Brass, Goss and S) have been characterized after channel-die compression up to true strains of 2.1 by EBSD in a FEG-SEM. There is a general tendency for the microbands to be non-crystallographic at low strains, then crystallographic, and finally mixed at high strains with some lamellar banding.The recovery behaviour (at 240-320°C) of the cold-rolled Al-0.1%Mn crystals (ε=2.1) was investigated by Vickers microhardness, EBSD and X-ray line broadening analysis. The microhardness recovery rates of the Brass oriented crystals are systematically lower than those of the Goss and S orientations. We thus suggest that the orientation dependency is ascribed to the relatively low misorientations developed by plastic straining in the Brass crystals (average about 4°) compared with the Goss and S orientations (about 7-8°).Finally, softening investigations in strongly deformed Al-0.1%Mn polycrystals were carried out to correlate the deformation microstructure with the cube recrystallization nucleation. Two major types of thin cube bands have been identified. Only the “intergranular” cube segments (usually between different S and Cu oriented grains) led to the formation of high growth rate recrystallized cube grains. The “transgranular” cube bands did not lead to a growth advantage for the cube components compared to components of the surrounding matrix.L’objectif de ma thèse consiste en l’étude de l’influence de l’orientation cristalline sur les microstructures de déformation et l’adoucissement (restauration, germination de la recristallisation) d’alliages Al-Mn.Les évolutions microstructurales de monocristaux d’orientation Laiton, Goss et S déformés en compression plane (0,15<ε<2,1) ont tout d’abord été caractérisées par la technique EBSD couplée à un MEB-FEG. Aux petites déformations, les microbandes s’alignent principalement sur les plans de cission maximale (indépendamment de l’orientation cristalline) ; alors qu’à des déformations plus importantes, elles s’alignent majoritairement sur les systèmes de glissement activés. Une structure lamellaire apparaît aux grandes déformations.Ensuite, les mécanismes de la restauration (à 240-320°C) dans ces mêmes monocristaux déformés (ε=2,1) ont été caractérisés par microdureté Vickers, par EBSD et par analyses des profils des pics de diffraction RX. La cinétique de restauration des monocristaux Laiton est systématiquement plus lente que celle des monocristaux Goss et S. L’influence de l’orientation serait alors attribuée aux faibles désorientations développées au cours de la déformation plastique pour les monocristaux Laiton (moyenne autour de 4°) comparativement à celles des monocristaux Goss et S (autour de 7-8°).Enfin, nous avons étudié l’adoucissement dans un polycristal déformé par une corrélation directe de la microstructure avant et après recuit. Deux principaux types de fragments Cube ont été mis en évidence dans l’état déformé. Seuls les fragments Cube « intergranulaires » permettent le développement rapide de grains Cube recristallisés
Influence of the crystalline orientation on deformation microstructure and softening in Al-Mn alloys.
No full textL’objectif de ma thèse consiste en l’étude de l’influence de l’orientation cristalline sur les microstructures de déformation et l’adoucissement (restauration, germination de la recristallisation) d’alliages Al-Mn.Les évolutions microstructurales de monocristaux d’orientation Laiton, Goss et S déformés en compression plane (0,15<ε<2,1) ont tout d’abord été caractérisées par la technique EBSD couplée à un MEB-FEG. Aux petites déformations, les microbandes s’alignent principalement sur les plans de cission maximale (indépendamment de l’orientation cristalline) ; alors qu’à des déformations plus importantes, elles s’alignent majoritairement sur les systèmes de glissement activés. Une structure lamellaire apparaît aux grandes déformations.Ensuite, les mécanismes de la restauration (à 240-320°C) dans ces mêmes monocristaux déformés (ε=2,1) ont été caractérisés par microdureté Vickers, par EBSD et par analyses des profils des pics de diffraction RX. La cinétique de restauration des monocristaux Laiton est systématiquement plus lente que celle des monocristaux Goss et S. L’influence de l’orientation serait alors attribuée aux faibles désorientations développées au cours de la déformation plastique pour les monocristaux Laiton (moyenne autour de 4°) comparativement à celles des monocristaux Goss et S (autour de 7-8°).Enfin, nous avons étudié l’adoucissement dans un polycristal déformé par une corrélation directe de la microstructure avant et après recuit. Deux principaux types de fragments Cube ont été mis en évidence dans l’état déformé. Seuls les fragments Cube « intergranulaires » permettent le développement rapide de grains Cube recristallisés.The aim of my tesis was to evaluate the influence of crystalline orientation in deformation microstructures and softening (recovery, recrystallization) in cold-rolled Al-Mn alloys.The deformation microstructures of Al–Mn single crystals (namely Brass, Goss and S) have been characterized after channel-die compression up to true strains of 2.1 by EBSD in a FEG-SEM. There is a general tendency for the microbands to be non-crystallographic at low strains, then crystallographic, and finally mixed at high strains with some lamellar banding.The recovery behaviour (at 240-320°C) of the cold-rolled Al-0.1%Mn crystals (ε=2.1) was investigated by Vickers microhardness, EBSD and X-ray line broadening analysis. The microhardness recovery rates of the Brass oriented crystals are systematically lower than those of the Goss and S orientations. We thus suggest that the orientation dependency is ascribed to the relatively low misorientations developed by plastic straining in the Brass crystals (average about 4°) compared with the Goss and S orientations (about 7-8°).Finally, softening investigations in strongly deformed Al-0.1%Mn polycrystals were carried out to correlate the deformation microstructure with the cube recrystallization nucleation. Two major types of thin cube bands have been identified. Only the “intergranular” cube segments (usually between different S and Cu oriented grains) led to the formation of high growth rate recrystallized cube grains. The “transgranular” cube bands did not lead to a growth advantage for the cube components compared to components of the surrounding matrix
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
Influence de l'orientation cristalline sur les microstructures de déformation et l'adoucissement d'alliages Al-Mn
No full textL objectif de ma thèse consiste en l étude de l influence de l orientation cristalline sur les microstructures de déformation et l adoucissement (restauration, germination de la recristallisation) d alliages Al-Mn.Les évolutions microstructurales de monocristaux d orientation Laiton, Goss et S déformés en compression plane (0,15< <2,1) ont tout d abord été caractérisées par la technique EBSD couplée à un MEB-FEG. Aux petites déformations, les microbandes s alignent principalement sur les plans de cission maximale (indépendamment de l orientation cristalline) ; alors qu à des déformations plus importantes, elles s alignent majoritairement sur les systèmes de glissement activés. Une structure lamellaire apparaît aux grandes déformations.Ensuite, les mécanismes de la restauration (à 240-320C) dans ces mêmes monocristaux déformés ( =2,1) ont été caractérisés par microdureté Vickers, par EBSD et par analyses des profils des pics de diffraction RX. La cinétique de restauration des monocristaux Laiton est systématiquement plus lente que celle des monocristaux Goss et S. L influence de l orientation serait alors attribuée aux faibles désorientations développées au cours de la déformation plastique pour les monocristaux Laiton (moyenne autour de 4) comparativement à celles des monocristaux Goss et S (autour de 7-8).Enfin, nous avons étudié l adoucissement dans un polycristal déformé par une corrélation directe de la microstructure avant et après recuit. Deux principaux types de fragments Cube ont été mis en évidence dans l état déformé. Seuls les fragments Cube intergranulaires permettent le développement rapide de grains Cube recristallisés.The aim of my tesis was to evaluate the influence of crystalline orientation in deformation microstructures and softening (recovery, recrystallization) in cold-rolled Al-Mn alloys.The deformation microstructures of Al Mn single crystals (namely Brass, Goss and S) have been characterized after channel-die compression up to true strains of 2.1 by EBSD in a FEG-SEM. There is a general tendency for the microbands to be non-crystallographic at low strains, then crystallographic, and finally mixed at high strains with some lamellar banding.The recovery behaviour (at 240-320C) of the cold-rolled Al-0.1%Mn crystals ( =2.1) was investigated by Vickers microhardness, EBSD and X-ray line broadening analysis. The microhardness recovery rates of the Brass oriented crystals are systematically lower than those of the Goss and S orientations. We thus suggest that the orientation dependency is ascribed to the relatively low misorientations developed by plastic straining in the Brass crystals (average about 4) compared with the Goss and S orientations (about 7-8).Finally, softening investigations in strongly deformed Al-0.1%Mn polycrystals were carried out to correlate the deformation microstructure with the cube recrystallization nucleation. Two major types of thin cube bands have been identified. Only the intergranular cube segments (usually between different S and Cu oriented grains) led to the formation of high growth rate recrystallized cube grains. The transgranular cube bands did not lead to a growth advantage for the cube components compared to components of the surrounding matrix.ST ETIENNE-ENS des Mines (422182304) / SudocSudocFranceF
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
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