1,720,977 research outputs found
Opportunities and Challenges in the Synthesis, Characterization, and Catalytic Properties of Controlled Nanostructures
No full textCatalysis is a pillar of green chemistry and a crucial technology in achieving sustainability and reducing environmental concerns while still maintaining a high standard of living. Better catalytic materials, showing improved activity, selectivity, and stability, are at the core of future sustainable processes at the nexus of food, water, and energy. Fundamental understanding of catalyst operation is key for the preparation of improved heterogeneous systems for several catalytic applications. In order to develop fundamental knowledge about catalytic processes that would allow us to better design and tune catalytic materials, well-defined catalytic structures are important. Materials with well-defined morphologies can indeed facilitate and accelerate the discovery and description of active sites, which is the first, crucial step in better understanding catalytic systems. Once the active sites are known, it is then possible to build materials where the density of active sites is maximized, leading to improved systems with appropriate morphologies for best catalytic results. In this chapter, we will provide the fundamental basis and rationale for the development of controlled nanostructures in heterogeneous catalysis. We will briefly summarize synthetic procedures to achieve high control over catalytic nanostructures and illustrate important cases where this control resulted crucial for the final catalytic application. This material will lead us to a discussion of the opportunities and challenges in the field, with a positive look into the future of the catalysis field where controlled nanomaterials will play an increasingly important role
Preface: Morphological, Compositional, and Shape Control of Materials for Catalysis
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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
A model to determine the chemical expansion in non-stoichiometric oxides based on the elastic force dipole
No full textIn this work a novel continuum model informed by density functional theory (DFT) simulations is presented and used to predict the chemical expansion observed in non-stoichiometric oxides. We introduce an elastic dipole tensor that describes the long-range elastic fields created upon formation of oxygen vacancies. We show that this tensor, which can be accurately determined through first-principle DFT calculations, can be used to predict the chemical expansion of ceria and in general other non-stoichiometric oxides. Compared to previous work where expansivity was obtained with empirical potentials, our work provides an efficient way of computing it directly by DFT calculations. Furthermore, we discuss how the elastic dipole tensor can predict the O2 partial pressure vs O/Ce ratios in strained systems and show that CeO2 can be reduced more easily in the presence of tensile strains. More generally, the elastic dipoles can be used in continuum models to predict the distribution of vacancies near nanocrystal surfaces, grain boundaries and extended defects such as dislocations and hence provide information on how these structures and defects influence the overall reducibility of the material
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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