1,721,082 research outputs found
Proccedings of the 1st World Congress on “Environmental Catalysis – For a Better World and Life”
No full textPreparation, performances and reaction mechanism for the synthesis of H2O2 from H2 and O2 based on palladium membranes
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Palladium-modified catalytic membranes for the direct synthesis of H2O2: preparation and performance in aqueous solution
No full textA series of new tubular catalytic membranes (TCMs) have been prepared and tested in the direct synthesis of H2O2. Such TCMs are
carbon-coated asymmetric α-alumina mesoporous membranes supported on macroporous α-alumina. Pd was introduced by deposition–
precipitation to obtain an even Pd particle distribution inside the membrane pore network. This type of membrane was active in the direct
synthesis of H2O2. Catalytic tests were carried out in a semi-batch recirculating reactor under very mild conditions. Concentrations as high
as 250–300 ppm H2O2 were commonly achieved after 6–7 h on stream, with a particularly high decomposition rate in the presence of H2.
Important features are optimization of the metal deposition procedure and preactivation. To slow down the decomposition and favor the
synthesis of H2O2, a smooth metal particle surface is needed.
2005 Elsevier Inc. All rights reserved
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
Carbon Nanostructures Decorated with Titania: Morphological Control and Applications
Full text linkNanostructured titania (TiO2) is the most widely applied semiconducting oxide for a variety of purposes, and it is found in many commercial products. The vast majority of uses rely on its photo-activity, which, upon light irradiation, results in excited states that can be used for diverse applications. These range from catalysis, especially for energy or environmental remediation, to medicine—in particular, to attain antimicrobial surfaces and coatings for titanium implants. Clearly, the properties of titania are enhanced when working at the nanoscale, thanks to the increasingly active surface area. Nanomorphology plays a key role in the determination of the materials’ final properties. In particular, the nucleation and growth of nanosized titania onto carbon nanostructures as a support is a hot topic of investigation, as the nanocarbons not only provide structural stability but also display the ability of electronic communication with the titania, leading to enhanced photoelectronic properties of the final materials. In this concise review, we present the latest progress pertinent to the use of nanocarbons as templates to tailor nanostructured titania, and we briefly review the most promising applications and future trends of this field
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