1,720,966 research outputs found
Recent Advances in the Use of Black TiO2 for Production of Hydrogen and Other Solar Fuels
No full textBlack TiO2 has emerged as one of the most promising photocatalysts recently discovered. The reason behind its catalytic activity is considered to be due to the presence of defects and Ti3+ species at the surface of black TiO2 nanostructures, which are crucial for its diverse applications. Moreover, disordered/crystalline surface layers and bulk regions have been identified and appear to influence the intrinsic properties of the material. Here, we present the latest studies on the use of black TiO2 for metal free hydrogen production, as well as for CO2 photoreduction and N2 photofixation. After highlighting the structure/property relations, we conclude with some critical questions and suggest further topics of research in order to better understand the underlying mechanisms of light absorption in black TiO2, especially towards solar fuels production
Solid-state photoelectrochemical cell with TiO2 nanotubes for water splitting
No full textWe have fabricated and tested a photoelectrochemical (PEC) cell where the aqueous electrolyte has been replaced by a proton conducting hydrated Nafion® polymer membrane. The membrane was sandwiched between a TiO2-based photoanode and a Pt/C-based cathode. The performance was tested with two types of photoanode electrodes, a thermally prepared TiO2 film on Ti foil (T-TiO2) and a nanostructured TiO2 films in the form of highly ordered nanotubes (TNT) of different lengths. Firstly, photovoltammetry experiments were conducted under asymmetric conditions, where the anode was immersed in deionized water, while the cathode was kept in ambient air. The results showed a high incident photon-to-current efficiency (IPCE) of 19% under unassisted conditions (short-circuit, 0 V vs. cathode) with short TNT (ca. 1 μm) under 4 mW cm−2 illumination with UV-A rich light. Secondly, the deionized water was replaced by 0.5 M Na2SO4 and now the performance was higher with longer nanotubes, assigned to increased ionic conductivity inside the tubes. An unassisted (0 V) IPCE of 33% was achieved with nanotubes of ca. 8 μm. The presented solid-state PEC cell minimizes the electrode distance and volume of the device, and provides a way towards compact practical applications in solar water splitting
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
Photocatalytic generation of gas phase reactive oxygen species from adsorbed water: Remote action and electrochemical detection
No full textThe improvement of indoor environments is of great importance as it can significantly improve human health, comfort and productivity. Herein, different forms of TiO2 nanorods were used as the photocatalyst for generation of reactive oxygen species (ROS) in a gas phase photoreactor under controlled humidity. Several parameters were investigated by monitoring the remote decolourisation of Methylene Blue (MB) embedded in a Nafion film. A decolourisation of 26% under 80% relative humidity was observed when the MB film was 0.5 cm away from the photocatalyst. The length and ratio of light/dark intervals have major impacts on the efficiency of the gas phase photocatalytic process, which we link to the amount of water adsorbed on the photocatalyst, as the source for hydroxyl radicals. Furthermore, the photocatalytic production of ROS was quantified through a polyaniline electrochemical sensor and a rate of 1 · 10*12 of ROS molecules s−1 was estimated. This study contributes to the efficacy of the gas phase photocatalytic method in air decontamination, for the development of efficient air cleaning devices
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
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