1,720,954 research outputs found
Evaluation des performances d\u27un aérateur a jet vertical pour l\u27oxygénation des boues activées. Hydrodynamique et transfert de matière
No full textCe travail concerne létude dun réacteur gaz-liquide à jet vertical descendant, appartenant à la catégorie des colonnes à bulles et fonctionnant à co-courant. Le but est de lutiliser comme aérateur des boues de station dépuration. Létude concerne la détermination de son efficacité en transfert doxygène par mesure du coefficient volumétrique de transfert de matière kLa en eau claire comme en présence de boues. En eau claire, ce paramètre a été déterminé par trois méthodes différentes, à savoir la méthode du gazing out, labsorption gaz-liquide avec réaction chimique et la méthode des bilans gazeux. Quant aux boues activées, les valeurs de kLa sont obtenues par deux méthodes : la réoxygénation des boues et la méthode au peroxyde dhydrogène. Les valeurs obtenues en eau claire sont comparées à celles obtenues en présence de boues ce qui permet de déterminer le facteur (rapport de kLa boue/kLa eau claire). Au préalable les rétentions gazeuses et la puissance dissipée ont été déterminées et les écoulements caractérisés. Enfin lApport Spécifique Brut (ASB: quantité doxygène transférée sur la quantité dénergie dépensée) est comparé à celui obtenu dans dautres réacteurs susceptibles dassurer laération dun liquide. Les résultats obtenus montrent que le réacteur à jet est parmi les aérateurs les plus performants
Evaluation des performances d'un aérateur a jet vertical pour l'oxygénation des boues activées (Hydrodynamique et transfert de matière)
No full textCe travail concerne l étude d un réacteur gaz-liquide à jet vertical descendant, appartenant à la catégorie des colonnes à bulles et fonctionnant à co-courant. Le but est de l utiliser comme aérateur des boues de station d épuration. L étude concerne la détermination de son efficacité en transfert d oxygène par mesure du coefficient volumétrique de transfert de matière kLa en eau claire comme en présence de boues. En eau claire, ce paramètre a été déterminé par trois méthodes différentes, à savoir la méthode du gazing out, l absorption gaz-liquide avec réaction chimique et la méthode des bilans gazeux. Quant aux boues activées, les valeurs de kLa sont obtenues par deux méthodes : la réoxygénation des boues et la méthode au peroxyde d hydrogène. Les valeurs obtenues en eau claire sont comparées à celles obtenues en présence de boues ce qui permet de déterminer le facteur (rapport de kLa boue/kLa eau claire). Au préalable les rétentions gazeuses et la puissance dissipée ont été déterminées et les écoulements caractérisés. Enfin l Apport Spécifique Brut (ASB: quantité d oxygène transférée sur la quantité d énergie dépensée) est comparé à celui obtenu dans d autres réacteurs susceptibles d assurer l aération d un liquide. Les résultats obtenus montrent que le réacteur à jet est parmi les aérateurs les plus performants.The aim of this work is to investigate a co-current air-liquid downward flow bubble column with air entrainment by liquid injection nozzle in order to use it as an aerator in activated sludge treatment plants. The study concerns the determination of oxygen transfer efficiency by measuring the mass transfer coefficient kLa both in clean water and in activated sludge. In clean water, this parameter is determined by three methods: Gassing out method, absorption with chemical reaction and off gas method. In activated sludge medium, kLa values are measured by two methods: sludge reoxygenation and hydrogen-peroxide method. The values of kLa obtained in clean water are compared to those of the obtained in sludge, enabling to assess the factor (ratio of oxygen transfer coefficient sludge/clean water). Previously the determination of gas hold-ups, power dissipated and characterization of fluids flow were carried out. Finally the oxygen transfer efficiency (OE) is determined and compared to those obtained in other reactors able to aerate the liquids. The obtained results show that our reactor is among the most performed ones.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF
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
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