1,720,981 research outputs found
Experimental characterization of tritium extraction systems and tritium anti-permeation barriers in heavy liquid metal systems
No full textThis work lies within the framework of the development of advanced nuclear reactors, dealing with the research on tritium technologies, such as extraction systems for
the Water Cooled Lithium-Lead Breeding Blanket (WCLL BB) of the EU DEMO fusion reactor and anti-permeation coatings for IV generation fission Lead-cooled Fast Reactors (LFR). On the first topic, the aims of this thesis are to provide the first characterization of the Permeator Against Vacuum (PAV) technology and to contribute to the research on the Gas-Liquid Contactor (GLC). Instead, the characterization at ALFRED LFR relevant conditions of the Pulsed Laser Deposition (PLD) coatings is the aim of the second part of the thesis. The two parts of the thesis are joined together by the common theoretical background of tritium transport. The first part took advantage of the experimental facility TRIEX-II, located at ENEA Brasimone R.C., which has been refurbished and intensively operated to contribute to the characterization of the PAV and GLC technologies.
The PAV has been often considered as the reference technology to extract tritium from LiPb, but it has never been tested in relevant conditions, nor a sizeable mock-up has ever been completed before. In this thesis, the engineering design and fabrication of a niobium-based PAV are shown, with particular attention paid on the manufacturing processes and on the selected equipment. The mock-up has been integrated in TRIEX-II and tested at different hydrogen partial pressures and LiPb temperatures, demonstrating that a PAV can be manufactured and operated at relevant conditions. The experiments showed that the permeated flux was in the order of 10−9 mol/s at 350 ◦C and increased, at 450 ◦C, to about 10−8 mol/s. The activity on PAV is complemented by data on the compatibility of niobium in flowing LiPb, obtained by exposing samples at 0.5 m/s and 500 ◦C in IELLL O facility, also located at ENEA Brasimone R.C., for about 4000 hours. Vanadium, the other PAV candidate material, was also exposed in the same campaign. The samples of both materials withstood the aggressive environment but a tendency was noted to form ternary compounds with nickel, already dissolved in LiPb.
A complementary experimental campaign aimed at providing new data on the GLC operation and showed low extraction efficiencies, caused by the strong corrosion of the packings. The lessons learnt in this campaign on instrumentation and packings were useful for the PAV experiments and are being used to prepare a new GLC campaign that will be performed during Fall 2022. The second part of the thesis deals with the fusion-fission cross-cutting subject of alumina coatings, which have the double task of reducing corrosion of structural materials and minimizing tritium permeation towards the coolant in the WCLL BB and in the primary loop of ALFRED lead fast reactor. In this field, the main achievement has been the design and construction of an innovative experimental apparatus, named APRIL, also located at ENEA Brasimone R.C., that is capable of testing permeation from a gas phase towards water in relevant conditions for fusion and fission reactors. This facility has been used to measure the Permeation Reduction Factor (PRF) of 3 μm alumina coatings made by PLD with deuterium concentration of 0.5% and water at ALFRED conditions. The evaluated PRF is about 13.5. A second activity on coatings has been devoted to test their effectiveness in reducing the corrosion rate of EUROFER and their resistance in flowing LiPb by exposing samples in the same IELLLO campaign mentioned above. While PLD-made coatings protected the EUROFER samples and resisted to the LiPb corrosive attack, those made by Atomic Layer Deposition showed a tendency to detach from the substrate, leaving EUROFER exposed to the LiPb flow. Finally, both coatings revealed a grainy appearance related to the formation of LiAl-oxides
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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