1,720,953 research outputs found
High-Power Electrical Energy Conversion Systems for Industrial Production with Reduced Environmental Impact
No full textScientific consensus on anthropogenic climate change calls for drastic emissions reduction. Electrification is the cornerstone of this transition and needs backing by clean energy generation and modern grids. Both aspects rely on large-scale deployment of power converters and energy storage systems since the power quality and stability of traditional power systems are challenged by renewable energy sources’ non-dispatchable nature. Indeed, electrification’s growing energy demand drives a widespread need for high-power converter systems. At generation and distribution levels, converters actively control power flows and integrate storage to ensure power quality and resilience. High-power isolated converters (i.e., solid-state transformers, SSTs), supported by advanced control and communication, will constitute smart grids capable of supplying high power to, e.g., electric vehicles (EVs), datacenters, and high-power industrial loads. The rapid pace of deployment calls for careful attention to all aspects that can catalyze their series production and adoption.
In this context, the scope of this research project is to improve power converters in some of their aspects (e.g., efficiency, power density, material use, control performance) for lessening, either directly or indirectly, the environmental impact of the industry and transportation sectors, possibly by catalyzing new applications for an electrified economy. Towards this end, modularity is identified as a key feature, e.g., low-power power electronic building blocks (PEBBs) can be purposely combined to obtain a high-power system, enabling scalability, cost reduction, and increasing availability, with the drawback of increased complexity.
Prominent modular high-power converters, isolated and nonisolated, have been studied. In Part I, SSTs are discussed, also focusing on the conversion from medium-voltage AC (MVAC) to low-voltage DC (LVDC) as the most promising applications (e.g., for datacenters and fast EV charging). A modular SST has been investigated as derived from a recent patent that claimed hardware simplification. This work provided the first analyses on this new SST, greatly advancing its modeling, control, and high-level design, also providing a comparative evaluation against another SST and testing with refined simulations.
In SSTs, the isolation is provided by high-density transformers operating at increased frequencies that makes their design nontrivial. To contribute on this issue, this thesis studied a high-frequency transformer for a resonant CLLC converter working as a DC solid-state transformer (DCX), experimentally evaluating different winding configurations to explore the trade-off between electrical performance and ease of manufacturing.
In Part II, this work focuses on a prominent application for the heavy industry, proposing, motivating, and analyzing the application of the modular multilevel converter (MMC) to accelerate the deployment of next-generation electric arc furnaces (EAFs) for steelmaking with extended modularity than the state-of-the-art. A first feasibility study shows that the novel solution can match the existing one in power density but with improved modularity and scalability. Then, a novel control strategy tailored for this peculiar non-linear load (i.e., the electric arc) is provided and validated through advanced simulations, and a scaled-down prototype has been designed.
Several original scientific contributions have already been presented at the most relevant international conferences and have been the result of fruitful collaboration with national and international partners.
Ultimately, recognizing both the importance of innovation and industrial adoption, these findings pave the way for future research into SSTs and expanded MMC applications to ensure that power electronics remain at the forefront of the global transition toward cleaner and more resilient energy systems
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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