1,721,010 research outputs found
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
Design and structural optimization of a high entropy alloy (HEA) of the CoCrFeMnNi family with high mechanical resistance.
No full textLes alliages à haute entropie (high entropy alloys ou HEAs en anglais) sont une nouvelle classe de matériaux obtenus avec nouvelle approche originale. Ils sont constitués d'au moins 5 éléments dans des proportions similaires, ce qui entraîne une entropie accrue du mélange du système et donc une plus grande stabilité des solutions solides.Dans ce travail, un nouveau HEA basé sur CoCrFeMnNi a été optimisé, caractérisé et breveté. Cet alliage, appelé A3S, est constitué de 5 éléments en proportions non équiatomiques. Cette composition a été optimisée avec CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) dans le logiciel Thermo-Calc. Le matériau possède une structure de solution solide cubique à face centrées et qui, contrairement à la structure équiatomique, reste stable après un recuit à 500°C jusqu'à 300 jours. La facilité de formation d'une nanostructure après forgeage à chaud est remarquable et résulte en une résistance élevée ainsi qu'une bonne ductilité. Ces propriétés sont améliorées aux températures cryogéniques où un mécanisme supplémentaire de déformation par le maclage est activé. Une étude comparative entre le nouvel A3S et le matériau de référence équiatomique a été réalisée. Tout d'abord, la procédure d'optimisation de l'alliage par des calculs thermodynamiques a été présentée. Ensuite, les microstructures et les propriétés mécaniques dans différentes conditions (différentes températures et durées de recuit ainsi que les types de déformation) ont été examinées. Enfin, la dernière partie passe en revue les mécanismes de restauration et de recristallisation qui diffèrent significativement des matériaux classiques.High entropy alloys (HEAs) are a new class of materials obtained with a novel approach. They are made of at least 5 elements in similar proportions, which results in increased configurational entropy of the system and in some cases in higher stability of single solid solutions.In this work, a novel HEA based on equiatomic CoCrFeMnNi was optimized, characterized and patented. This alloy, referred to as A3S (austenitic super stainless steel), consists of 5 elements in non-equiatomic proportions (Co20Cr15Fe26Mn17Ni22). This composition was optimized with CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) in Thermo-Calc software. The material possesses stable face-cubic centered solid solution structure and, unlike the equiatomic one, remains stable after annealing at 500oC up to 300 days. The facility of forming a nanostructure after hot forging is remarkable, and results in high resistance as well as ductility compared to stainless steels. These properties are improved at cryogenic temperatures where an additional mechanism of deformation by twinning is being activated. This compilation of properties is very promising for industry where new materials are required.A comparative study between the novel A3S and the equiatomic reference material has been conducted. First, the procedure of the alloy optimization by thermodynamic calculations has been presented. Then, microstructures and mechanical properties in different conditions (various annealing temperatures and times as well as types of deformation) have been examined. Finally, the last part reviews the mechanisms of recovery and recrystallization which differ significantly from classical materials
Non destructive analysis of grain sub-structuration in single grains of an Aluminium polycrystal deformed in uniaxial tension.
No full textCe travail vise à améliorer la compréhension des mécanismes et de la dynamique de sous-structuration des grains pendant la deformation des matériaux polycristallins. Pour cela, des experience in situ en synchrotron et des acquisitions EBSD ont été menées afin d’étudier les comportements des grains individuels d’un polycrystal d’Aluminium déformé plastiquement. Une éprouvette d’un alliage Al-0.1%Mn a été déformée en traction in situ et analysée par microscopie 3D par diffraction des Rayons-X (3DXRD). Une nouvelle méthode de dépouillement a été développée pour determiner les axes de désorientation intragranulaires et les distributions d’orientation, grâce à l’analyse de l’élargissement azimutal des taches de diffraction. La technique EBSD a été appliquée pour obtenir des cartographies de désorientation des grains individuels d’une éprouvette déformée en traction. Trois acquisitions ont été réalisées sur la même région d’intérêt à l’état non déformé et après l’application des deformations 1% et 5%. Ces résultats permettent une meilleure comprehension de la formation et de l’évolution des gradients d’orientations intragranulaires, et son ten bon accord avec les modèles théoriques pré-existants. Aussi, la caractérisation de la sous-structuration des grains et de la deformation intragranulaire a été réalisée grâce à la technique K-map. La deformation était très hétérogène avec des valeurs élevées de compression et de traction à l’intérieur des grains et en proximité de deux joints de grains, respectivement. La distribution de la norme des vecteurs de diffraction a montré que les dislocations sont à l’origine de la deformation.This work aims to improve the understanding of grain sub-structuration mechanisms and dynamics during deformation of polycrystals. For this purpose, in situ synchrotron experiments and EBSD acquisitions were coupled to study the response of single grains of an Al-0.1%wt.Mn polycrystal during tensile deformation. The specimen deformed in situ at the synchrotron was analyzed by 3DXRD. A new method provided a grain-by-grain analysis of the intragranular misorientation axes and their orientation distribution, through the investigation of the azimuthal broadening of diffraction spots. The 3DXRD results were cross-checked by classical EBSD analysis. Three acquisitions were carried out over the same region of interest at the undeformed state and after the application of 1% and 5% strain. Thanks to the available spatial resolution, the EBSD results allow for a better comprehension of the creation and dynamics of intragranular orientation gradients, and are in good agreement with pre-existing theoretical models. In addition, the characterization of grain sub-structuration and intragranular strain was performed through a novel X-Ray scanning technique, the K-map. The strain was found to be very heterogeneous with high compressive and tensile values in the grain interior and near two grain boundaries, respectively. Dislocations were found to be at the origin of deformation
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
Contribution to the study of the monotonie and cyclic behavior of welded austenitic 3 l 6L and duplex 2101 stainless steels
No full textCe travail de thèse vise à apporter des éléments de compréhensions sur les mécanismes endommagement par fatigue des réservoirs en aciers inoxydables (fabriqués par e.l.m. Leblanc). Nous nous sommes intéressés à identifier les facteurs influençant la tenue en fatigue de réservoirs lors du chargement cyclique de pression. Dans le but de distinguer les stades d'amorçage et de propagation de fissure, nous étudions le comportement en flexion cyclique des soudures modèles. Ces résultats ont permis également d'évaluer l'influence du procédé sur le comportemen des soudures. Nous complétons cette étude par des observations in-situ des mécanismes d'amorçage et de propagation d�� fissures en présence <l'entaille.This thesis work aims to provide elements of understanding on the fatigue damage mechanisms of stainless steel tanks (manufactured by e.l.m. Leblanc). We are interested in identifying the factors influencing the fatigue behavior of tanks during cyclic pressure loading. ln order to distinguish the stages of crack initiation and propagation, we study the cyclic behavior of model welds. These results also made it possible to evaluate the influence of the process on the behavior of the welds. We complete this stud) with in-situ observations of crack initiation and propagation mechanisms in the presence of a notch
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