1,720,961 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
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
Poudres PEKK pour la fabrication additive par fusion laser
No full textNowadays, the need to develop ever more innovative and efficient materials puts constant pressure on a large number of industrial sectors. Among them, aeronautics, aerospace, transport and energy production sectors seek to lighten the structure of their equipment in order to reduce energy consumption and minimize their environmental footprint. This reduction generally results in the conversion of metallic and dense materials towards plastic and lighter materials. The specificities of these industrial sectors, as well as the conditions of temperature, pressure, and accelerated aging to which some of their equipment are constrained, impose very precise specifications. The selective laser sintering process (also called SLS), recently implemented for the manufacture of thermoplastic parts, is of great interest for these different sectors of activity in which custom-made parts with complex geometry are often required. This process consists of the layer-by-layer manufacturing of parts by selective melting of powder by a laser beam. PEKK, a high performance semi-crystalline thermoplastic copolymer, validates many of the criteria for use in SLS manufacturing. However, the still limited knowledge that we have of this polymer, as well as its copolymer-like structure, still require substantial research work to this day. The aim of this work was to deepen our knowledge of the properties of crystallization and melting of a commercially available PEKK grade designed for use in SLS. These properties are of key importance for the successful implementation of the SLS process. A second objective was to develop a new grade of PEKK copolymers with a regular structure. In order to better understand the crystallization properties of our polymers, a model was used and a combination of SAXS / WAXS, DSC and rheological studies is carried out. The way of using in SLS the new grade of PEKK, hitherto very little explored, was also studied. We demonstrated that the copolymer with the regular chain structure exhibits a much simpler crystallization mechanism and a higher crystallization enthalpy which may be a advantage for use in SLS.De nos jours, la course au développement de matériaux toujours plus innovants et performants fait subir une constante pression à un grand nombre de secteurs industriels. Parmi eux, l’aéronautique, l’aérospatial, les secteurs de transport et de production d’énergie cherchent à alléger la structure de leurs équipements afin d’en réduire la consommation en énergie et minimiser leur empreinte environnementale. Cet allègement se traduit généralement par la conversion des matériaux métalliques et denses vers des matériaux plastiques et plus légers. La spécificité de ces domaines d’utilisation, ainsi que les conditions de température, de pression, et de vieillissement accéléré auxquelles sont contraints certains de leurs équipements imposent néanmoins un cahier des charges très précis. Le procédé de frittage sélectif par laser (également appelé SLS), récemment mis en œuvre pour la fabrication de pièces thermoplastiques, constitue un grand intérêt pour ces différents secteurs d’activité dans lesquels des pièces sur mesure et à géométrie complexe sont requises. Ce procédé consiste à la fabrication couche par couche de pièces par fusion sélective de grains de poudre à l’aide d’un laser. Le PEKK, copolymère thermoplastique semi-cristallin de hautes performances, valide de nombreux critères lui permettant d’être, depuis quelques années, utilisé dans la fabrication de pièces par SLS. Cependant, la connaissance encore limitée que nous avons de ce polymère complexe, ainsi que sa structure de type copolymère, nécessitent encore à ce jour un travail de recherche conséquent. Cette thèse a eu ainsi pour but, sur une famille de PEKK déjà commercialisée, d’approfondir nos connaissances des propriétés de cristallisation et de fusion qui jouent un rôle essentiel dans la fabrication de pièces par la technologie SLS. Un deuxième objectif était de développer une nouvelle famille de copolymères PEKK à structure régulière. Afin de comprendre au mieux les propriété s de cristallisation de nos polymères, un modèle a été utilisé et une mise en commun de données SAXS / WAXS, DSC et rhéologiques est réalisée. La voie d’une utilisation en SLS d’une nouvelle famille de PEKK à chaîne alternée, jusque-là très peu explorée, a également été étudiée
Poudres PEKK pour la fabrication additive par fusion laser
No full textNowadays, the need to develop ever more innovative and efficient materials puts constant pressure on a large number of industrial sectors. Among them, aeronautics, aerospace, transport and energy production sectors seek to lighten the structure of their equipment in order to reduce energy consumption and minimize their environmental footprint. This reduction generally results in the conversion of metallic and dense materials towards plastic and lighter materials. The specificities of these industrial sectors, as well as the conditions of temperature, pressure, and accelerated aging to which some of their equipment are constrained, impose very precise specifications. The selective laser sintering process (also called SLS), recently implemented for the manufacture of thermoplastic parts, is of great interest for these different sectors of activity in which custom-made parts with complex geometry are often required. This process consists of the layer-by-layer manufacturing of parts by selective melting of powder by a laser beam. PEKK, a high performance semi-crystalline thermoplastic copolymer, validates many of the criteria for use in SLS manufacturing. However, the still limited knowledge that we have of this polymer, as well as its copolymer-like structure, still require substantial research work to this day. The aim of this work was to deepen our knowledge of the properties of crystallization and melting of a commercially available PEKK grade designed for use in SLS. These properties are of key importance for the successful implementation of the SLS process. A second objective was to develop a new grade of PEKK copolymers with a regular structure. In order to better understand the crystallization properties of our polymers, a model was used and a combination of SAXS / WAXS, DSC and rheological studies is carried out. The way of using in SLS the new grade of PEKK, hitherto very little explored, was also studied. We demonstrated that the copolymer with the regular chain structure exhibits a much simpler crystallization mechanism and a higher crystallization enthalpy which may be a advantage for use in SLS.De nos jours, la course au développement de matériaux toujours plus innovants et performants fait subir une constante pression à un grand nombre de secteurs industriels. Parmi eux, l’aéronautique, l’aérospatial, les secteurs de transport et de production d’énergie cherchent à alléger la structure de leurs équipements afin d’en réduire la consommation en énergie et minimiser leur empreinte environnementale. Cet allègement se traduit généralement par la conversion des matériaux métalliques et denses vers des matériaux plastiques et plus légers. La spécificité de ces domaines d’utilisation, ainsi que les conditions de température, de pression, et de vieillissement accéléré auxquelles sont contraints certains de leurs équipements imposent néanmoins un cahier des charges très précis. Le procédé de frittage sélectif par laser (également appelé SLS), récemment mis en œuvre pour la fabrication de pièces thermoplastiques, constitue un grand intérêt pour ces différents secteurs d’activité dans lesquels des pièces sur mesure et à géométrie complexe sont requises. Ce procédé consiste à la fabrication couche par couche de pièces par fusion sélective de grains de poudre à l’aide d’un laser. Le PEKK, copolymère thermoplastique semi-cristallin de hautes performances, valide de nombreux critères lui permettant d’être, depuis quelques années, utilisé dans la fabrication de pièces par SLS. Cependant, la connaissance encore limitée que nous avons de ce polymère complexe, ainsi que sa structure de type copolymère, nécessitent encore à ce jour un travail de recherche conséquent. Cette thèse a eu ainsi pour but, sur une famille de PEKK déjà commercialisée, d’approfondir nos connaissances des propriétés de cristallisation et de fusion qui jouent un rôle essentiel dans la fabrication de pièces par la technologie SLS. Un deuxième objectif était de développer une nouvelle famille de copolymères PEKK à structure régulière. Afin de comprendre au mieux les propriété s de cristallisation de nos polymères, un modèle a été utilisé et une mise en commun de données SAXS / WAXS, DSC et rhéologiques est réalisée. La voie d’une utilisation en SLS d’une nouvelle famille de PEKK à chaîne alternée, jusque-là très peu explorée, a également été étudiée
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