1,720,964 research outputs found
Synthesis, Characterization and Photocatalytic Activity of NiO-Bi2O3 Nanocomposites
No full textNiO–Bi2O3 nanocomposite was synthesized and characterized. XRD analysis and UV–vis spectroscopy revealed that the two components of the composite retain their independent identity. Nevertheless, the smaller mean crystallite sizes of the NiO and Bi2O3 in the nanocomposite, compared to pure components, suggests the presence of an interaction between the two phases. Consistently the surface area of the nanocomposite is significantly higher with respect to that of the pure components. Photocatalytic activity was estimated for the decolorization of methylene blue and methyl orange. The nanocomposite, NiO–Bi2O3 showed significantly higher activity compared to its components in the pure phase
Photocatalytic activity of zinc modified Bi2O3
No full textThe surface of alpha-Bi2O3 was modified by either impregnating Zn acetate or coating with a sol-gel containing Zn hydroxide. The surface modified Bi2O3 powders were evaluated by UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and surface area analysis (BET). The photocatalytic performances were evaluated for the degradation of phenol, methylene blue and methyl orange. The variations in photocatalytic activity were correlated with morphology change. The presence of ZnO does not significantly prevent the progressive formation of photocatalytically inactive (BiO)(2)CO3, while the dye decolourization capability of nanocomposite is significantly preserved with respect to that of bare Bi2O
Sustainable photocatalytic synthesis of benzimidazoles
Full text linkAmong the 17 Sustainable Development Goals presented by the United Nations in 2015, great attention is devoted to the production of goods and chemicals by use of renewable raw materials, by recycling of products and by extensive use of renewable energy sources. In this context, photocatalysis attracted great attention for the possibility to exploit Solar light to promote the desired chemical reactions. Besides its use in degradation of pollutants and in the production of fuels, some efforts have been devoted in the development of photocatalytic processes for the synthesis of fine chemicals with high added-value. In this work, we investigated the sustainable photocatalytic synthesis of benzimidazole derivatives through a one-pot, tandem process starting from a nitro compound and ethanol. By a photocatalytic approach, ethanol is dehydrogenated producing the hydrogen required for reduction of nitro groups and the aldehyde required for cyclization and production of the benzimidazole unit. Co-doping of TiO2 with B and N is beneficial to increase the photocatalytic activity in H2 production from ethanol. The effect of various metal co-catalysts (Pt, Pd Ag, Cu) have been evaluated on H2 production rate and on selectivity in the synthesis of substituted benzimidazoles: Pt showed the highest selectivity in the desired products while Pd demonstrated a great activity for hydrodehalogenation, with potential interest for degradation of persistent pollutants
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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