1,720,953 research outputs found

    Power generation on board of a FPSO : a technical, environmental and economic comparison between open cycle gas turbines and combined cycle

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    LAUREA MAGISTRALEL’obiettivo della tesi, condotta in collaborazione con Eni, è quello di valutare la fattibilità dell’applicazione di un ciclo combinato a bordo di una unità galleggiante di produzione, stoccaggio e scarico (FPSO) che lavora nel giacimento Agogo, in Angola. Rispetto agli impianti attualmente più diffusi, basati su ciclo a gas semi-aperto con recupero termico dai gas di scarico della GT, il ciclo combinato permetterebbe un aumento dell’efficienza nella generazione di potenza e quindi una riduzione dell’impronta carbonica della compagnia. Fino ad oggi, però, i cicli combinati non sono adottati in questo ambito, soprattutto a causa degli stringenti limiti riguardo a peso e dimensioni dell’impianto a bordo della nave Lo scopo dello studio è di valutare la fattibilità attraverso i seguenti step: scelta dei principali componenti e del layout del ciclo; modellazione del ciclo combinato e del ciclo semi-aperto su Thermoflex e stima delle performances, in modo di verificare se il ciclo combinato è in grado di fornire i flussi di potenza richiesti; modellazione preliminare del layout dell’impianto di generazione di potenza (modelli 2D e 3D) e stima dei pesi, per verificare la fattibilità riguardo ai limiti di peso e dimensioni; studio della stabilità elettrica della rete per verificare la capacità di rispondere e adattarsi ad improvvisi cambiamenti di carico, generazione o altri guasti (senza l’effetto mitigante della rete elettrica, dato che questo scenario riguarda un impianto stand-alone). Infine, l’obiettivo è stimare i costi del progetto e calcolare le emissioni di anidride carbonica e gli altri principali KPI di sostenibilità, in modo di effettuare un paragone con il ciclo a gas semi-aperto e valutare la convenienza dell’investimento.The aim of the thesis, produced in collaboration with Eni, is to assess the feasibility of the application of a combined cycle on board of a Floating Production Storage and Offloading unit (FPSO) which operates in the Agogo oil field, in Angola. With respect to the widely diffused semi-open cycles with waste heat recovery unit, the combined cycle would allow an increase in the efficiency of power and thermal generation, thus, a reduction of the carbon footprint of the company. However, as of today, the combined cycles have not been adopted in this environment, mainly because of the strict constraints on weight and footprint on board of the vessel. The scope of this study is to evaluate the feasibility through the following steps: selection of the main components and the power cycle layout; modeling of the combined cycle and the semi-open cycle with Thermoflex and assessment of the performances, in order to check if the combined cycle fulfills the power duties; preliminary layout modeling (2D and 3D models) and weight assessment, to check the feasibility regarding footprint and weight constraints; transient stability analysis to check the capability of the electrical system to respond and adapt to sudden changes in load, generation or other faults (without the mitigating effect of the electrical grid, since it is a stand-alone power plant scenario). Lastly, the purpose is to assess the cost of the project and compute the carbon dioxide emissions and the other main sustainability KPIs, in order to make a comparison with the semi-open cycle and evaluate the convenience of the investment

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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 Under Sail The Imagination of Jack London, 1893-1902

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    In 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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