1,720,953 research outputs found
Power Performance and Response Analysis of a Semi-Submersible Wind Turbine Combined with Wave Energy Converters in Intermediate and Deep Water
Full text linkRenewable energies are the forefront against environmental pollution and the leading technology in sustainable energy sources. Power produced by wind energy is a well established technology. There is a lot of space for expansion though, especially at offshore environment. Floating wind turbines can take advantage of the abundant wind energy available far out at the oceans. Increasing the power production of such structures and ensuring the efficient and safe position keeping of them in every depth is crucial. Two concepts that aim to tackle down these two issues are proposed. A combination of wind and wave energy converters and an intermediate water depth mooring arrangement. The installation of wave energy converters (WECs) at the floating wind turbine base will reduce the levelized cost of energy (LCoE). The use of the same power cables and mooring arrangement to deploy the WECs can prove beneficial financially wise. Furthermore, it can act as a boost to the development of wave energy in general. The transient depth between shallow and deep is a challenging field for the traditional mooring arrangements. A cost effective solution will help the deployment of floating wind turbines in this intermediate water depth fields.
A novel concept of combining a floating wind turbine with WECs is proposed. A semi submersible floater is used to support a 5MW wind turbine. Three flap typed WECs are deployed on the pontoons of the floater. A two-point type absorber called Torus is installed at the central column. The proposed concept is named STFC. A thorough analysis of the natural periods, regular and irregular wave tests is performed to evaluate the effect of the WECs to the floater’s behavior. Small to no effect is observed across all degrees of freedom except the reduction in pitch period due to increased hydrostatic stiffness. The irregular wave tests indicate that the absorbed power amplitude operator (RAO) of Torus has a wider excitation range than the flaps. The floater heave RAO is affected by the addition of Torus and the floater surge and pitch RAOs are affected by the additions of flaps. Irregular waves tests are carried out to evaluate the influence of the added WECs to the motions of the combined concept and the total power performance. The results indicate that the WECs have little to no effect to the motions of the structure except the expected reduction in pitch motions. This is preliminary indication that no changes should be made to the mooring due to the addition of WECs. The wind turbine power performance is not affected by the addition of WECs. There is small reduction in pitch standard deviation though, in loading condition EC3 that leads to slightly better wind quality. The Torus performance is satisfactory as it accounts for 9% of the total STFC power production. The total three flaps account only for 14% of the Torus power production thus their power performance is not satisfactory. The flaps rotation is out of phase with the wave excitation force so there is room for improvement if active damping and stiffness control is added.
Following, the STFC is moved to intermediate water depth z = -50m and a new hybrid mooring design is proposed. A brief explanation of the intermediate water mooring challenges is given and the basic design criteria are established. A step to step designing process is presented. The combination of studded chain, buoys, and clump weights is proposed. The name of the concept is CCCB. A restoring force test is carried out and the linearity of the restoring force response is verified. Irregular wave tests are carried out and the data indicate that the new mooring design is a feasible design. The maximum floater offset is restrained to 14% of the water depth. The pretension of the mooring system proves to be a significant factor for the total performance of the mooring arrangement. The maximum mooring line tension is kept within safe limits throughout the whole offset range. CCCB is compared with similar concepts and proves itself stiffer mainly because of its increased pretension. Points of interest are defined across the mooring line and spectra analysis is performed to evaluate the distribution of response frequencies across the chain length. The role of buoys as dampers of motions is established. CCCB utilization factor indicates that this mooring design can be used also in larger structures and there is room for cost reduction measures
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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