1,720,955 research outputs found
Synthèse et caractérisation des nanoparticules de cobaltite de cuivre CuCo2O4 Application photocatalytique
Get PDFRésumé L’objectif de ce travail s’inscrit dans le cadre du développement de procédé photo catalytique efficace, pratique et économique pour la dépollution des eaux contenant des polluants colorants La première étude consacrée à la synthèse de cobaltite de cuivre CuCo2O4 par une méthode simple, peu coûteuse et respectueuse de l’environnement, selon un processus hydrothermal. Le matériau Synthétisé a été caractérisé par différents techniques telle que : IR, DRX, MEB, EDS, UV visible réflectance diffuse. L’analyse microstructurale, effectué grâce la méthode de Debye Scherer, a montré que la taille des cristallites est environ 53 nm. Par ailleurs, l’analyse IR montre la présence de liaisons CO et Co-O correspond aux bandes de vibrations 550 cm-1, 657 cm-1 respectivement. Les images MEB confirment la taille nanométrique et microscopique de l’oxyde synthétisé. Le résultat de réflectance diffuse a montré que le matériau CuCo2O4 a une énergie de gap de 2 ev, permettant une absorption important dans le do
Synthèse et caractérisation des nanoparticules de cobaltite de cuivre CuCo2O4 Application photocatalytique
Get PDFThe aim of this work is to develop an effective, practical and economical photo-catalytic process for
the decontamination of water containing coloring pollutants.
The first study focused on the synthesis of copper cobaltite CuCo2O4 using a simple, low-cost and
environmentally-friendly hydrothermal process. The material Synthesized material was
characterized by various techniques such as: IR, DRX, SEM, EDS, UV visible diffuse reflectance.
Microstructural analysis, performed using the Debye Scherer method, showed that the crystallite
size is around 53 nm.
In addition, IR analysis showed the presence of CO and Co-O bonds corresponding to vibration
bands 550 cm-1, 657 cm-1 respectively.
SEM images confirm the nanometric and microscopic size of the synthesized oxide.
Diffuse reflectance results showed that the CuCo2O4 material has a gap energy of 2 ev, enabling
significant absorption in the UV range.
EDS analysis confirmed the presence of all the elements in our material.
Photocatalytic experiments were carried out in the ultraviolet and visible range to understand the
effects of our sample on the degradation of rhodamine B at PH= 7 and Ph = 10. The CuCo2O4
spinel nanoparticles showed photo-catalytic responses in both the UV range (91% for pH=7 and
78% for pH=10) and the visible range; (80.4% pH =7, and for 65% pH =10), Finally, rhodamine B
degradation tests show that the nanoparticle offers high performance
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
- …
