1,720,953 research outputs found
The synthesis, modification and characterisation of metal incorporated H1 SIO2 mesoporous materials
No full textTwo approaches have been utilised for the modification of Hi SiOi mesoporous materials in order to produce well-defined active sites for catalysis: (i) the incorporation of transition metal salts into the synthesis gel in order to form Hi M/Si02 materials and (ii) the post- synthesis modification with Pt(acac)2 and various germanium additives (i.e. GeBu4, GeBugH, GePh4) and their subsequent decomposition/reduction to 673K under 10% hydrogen in nitrogen or pure nitrogen. The decomposition/reduction of Pt(acac)2 supported on amorphous silica and alumina has also been examined. The first part of this thesis describes the synthesis and characterisation of Hi M/Si02 (M = V, Cr, Fe, Co, Zn, Ga, Ge, Sn). It has been shown that the incorporation of metal sites via this methodology does not typically lead to direct incorporation into the silicate framework. However, the chromium incorporated material contains chromium as discrete species, with no formation of any oxide. Furthermore, characterisation suggests that the germanium has been successfully incorporated into the silicate 6amework and a new one-pot methodology for the incorporation of metal sites (i.e. Sn) has also been developed. A new methodology for the in situ study of heterogeneous systems utilising Energy Dispersive EXAFS (EDE) has been used to investigate the decomposition/reduction of Pt(acac)2 on various supports. Characterisation has shown that support choice has little influence on the 10% H2 in N2 reduction procedure, although the desorption of carbonaceous fragments was influenced, with the temperature of complete carbon removal shown to be Hi Si02<Si02-Al203. However, decomposition of supported Pt(acac)2 in a N2 atmosphere was shown to be influenced by support choice and follows a two stage decomposition mechanism, reducing over a broader temperature range (80K) and forming naked platinum particles at a much higher temperature (ca. 546K). The choice of support is observed to play an important role in defining platinum particle morphology. Most interestingly, the formation of platinum clusters, morphologically defined by the size and shape of the mesopores of the Hi Si02 material, show novel reactivity towards CO with the simultaneous appearance of three IR bands that are related to the terminal adsorption on CO. The incorporation of GeBu4 into the Pt(acac)2/Hi Si02 system leads to a significant modification in the H2/N2 reduction mechanism, with the EDE and TPR both indicating an increase in the reduction temperature range (ca. lOOK) and an increase in the fmal temperature in platinum particle formation (ca. 60K). At higher temperatures, the presence of germanium-platinum interactions indicates alloy formation. Ex situ characterisation of this system shows that Ge incorporation leads to significant modification of the platinum clusters with the formation of Pt-Ge alloys. The DRIFTS spectrum aAer CO adsorption exhibits only two bands, indicating that the Pt sites analogous to flat platinum surfaces are blocked, and the other platinum adsorption sites, proposed to relate to the high aspect ratio clusters, are unaffected by incorporation of GeBu4. However, further ex situ studies conducted using other germanium additives show that the choice of additive has signiGcant consequences on the reduction products. GeBusH influences only the high aspect ratio clusters, GePh4 impedes all CO adsorption by the formation of large arrays of Pt-Ge alloys (GePts, Ge2Pt3) and prior incorporation of the germanium into the mesoporous material appears to have no significant inGuence on the reduction products at all.</p
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
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
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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