1,720,953 research outputs found
CONVERSÃO FOTOELETROQUÍMICA DE METANO EM ENERGIA UTILIZANDO FOTOCÉLULAS A COMBUSTÍVEL BASEADAS EM FOTOÂNODOS DE BiVO4/CoOx
No full textClimate change associated with greenhouse gas emissions has driven the search for technologies capable of mitigating environmental impacts while simultaneously enabling sustainable energy generation. In this context, methane stands out due to its high global warming potential and elevated energy content, making it a strategic target for energy valorization processes. Among the available conversion technologies, photoelectrocatalysis emerges as a promising approach by employing solar energy to drive electrochemical reactions, combining energy recovery with environmental mitigation. This work investigates the performance of a methane-fed photo fuel cell (PFC) based on bismuth vanadate (BiVO4) photoanodes surface-modified with cobalt oxide (CoOx). BiVO4 has attracted significant attention as a photoanode material due to its suitable band gap of approximately 2.4 eV, enabling visible light absorption, chemical stability in aqueous solution, and relatively low cost, making it attractive for photoelectrochemical applications. The photoanodes were synthesized by electrodeposition followed by thermal conversion, while the CoOx cocatalyst was deposited on the surface through chemical impregnation and thermal treatment. Structural, morphological, optical, and electronic characterizations confirmed the preservation of the monoclinic phase of BiVO4, with an unchanged band gap of 2.46 eV, indicating that the modification predominantly affects the semiconductor/electrolyte interface. Mott–Schottky analysis revealed a shift in the flat-band potential from −0.02 to 0.15 VRHE and an increase in charge carrier density after CoOx modification. Electrochemical impedance spectroscopy demonstrated a significant reduction in polarization resistance, indicating improved charge transfer kinetics. During PFC operation, the BiVO4/CoOx photoanode exhibited a 64% increase in maximum power density when the anolyte was saturated with methane, reaching 0.38 mW under continuous flow conditions. These results demonstrate that the use of CoOx as a cocatalyst is an effective strategy to enhance the photoelectrochemical performance of BiVO4, highlighting the potential of this system for methane energy valorization and sustainable electricity generation.As mudanças climáticas associadas às emissões de gases de efeito estufa impulsionam a busca por tecnologias capazes de mitigar impactos ambientais e, simultaneamente, gerar energia de forma sustentável. Nesse contexto, o metano destaca-se por seu elevado potencial de aquecimento global e alto conteúdo energético, tornando-se um vetor estratégico para processos de valorização energética. Entre as tecnologias de conversão possíveis, a fotoeletrocatálise se destaca ao utilizar energia solar para promover reações eletroquímicas, aliando aproveitamento energético e mitigação ambiental. Este trabalho investiga o desempenho de uma fotocélula a combustível (PFC) alimentada com metano, baseada em fotoânodos de vanadato de bismuto (BiVO4) modificados superficialmente com óxido de cobalto (CoOx). O BiVO4 tem se destacado como fotoânodo por sua lacuna de banda de 2,4 eV, capaz de absorver luz na região do visível, além de estabilidade química em meio aquoso e baixo custo relativo, características que o tornam promissor para aplicações fotoeletroquímicas. Os fotoânodos foram sintetizados por eletrodeposição seguida de conversão térmica, e o cocatalisador CoOx foi ancorado na superfície por impregnação química e tratamento térmico. As caracterizações estruturais, morfológicas, ópticas e eletrônicas confirmaram a preservação da fase monoclínica do BiVO4, com bandgap de 2,46 eV, indicando que o cocatalisador atua predominantemente na interface semicondutor/eletrólito. As análises de Mott-Schottky revelaram um deslocamento do potencial de banda plana de −0,02 para 0,15 VRHE e aumento da densidade de portadores de carga após a modificação com CoOx. A espectroscopia de impedância eletroquímica evidenciou redução significativa da resistência de polarização, indicando melhora na cinética de transferência de carga. Em operação na PFC, o fotoânodo BiVO4/CoOx apresentou aumento de 64% na densidade de potência máxima quando o anolito foi saturado com metano, alcançando 0,38 mW em regime de fluxo contínuo. Os resultados demonstram que o uso de CoOx como cocatalisador é uma estratégia eficaz para aprimorar o desempenho fotoeletroquímico do BiVO4, evidenciando o potencial do sistema para a valorização energética do metano e geração sustentável de eletricidade
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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