1,721,023 research outputs found
Certification for Small Urban Wind Turbines: Verification of tlie lEC 61400-2 design methodology for a small wind turbine operating in the built environment
No full textMicrogeneration is a growing type of energy conversion used for generation of electricity in built environments such as urban areas. Among the different microgeneration technologies present in the market, small wind turbines have been showing a significant growth. The significant dissemination of its use and production and safety issues that arise from its deployment in urban areas have led to concerns in the insurance of its correct and safe design. Therefore the certification of the design process of these turbines is seen as an essential aspect to preserve this growing wind market worldwide. Currently, the design certification for Small Wind Turbines is set by the International Electrotechnical Commission in its lEC 61400-2 Ed.2 standard. It was considered that the present standard resulted from an adaptation and simplification of the lEC 61400-1 standard (used for the design large wind turbines), not considering some specific aspects typical of small wind turbines, nor the specific conditions of built environment wind conditions. The lEC 61400-2 standard introduces a methodology for load calculations based on a simplified load model by application of some simple equations. In order to validate this method for a small wind turbine operating in built environment wind conditions, aeroelastic modeling was used. Using real wind data obtained measured at an urban site (top of the Aerospace Engineering building), the loading on a 1.94 m rotor diameter turbine was analyzed by used of NWTC's FAST code. It was proven that the simplified load model underpredicted the loads for the maximum thrust load case. It was also proven that for the load case for Yawing, the simplified load model underpredicted the loading at yaw rates lower than the prescribed maximum. It was also proven that the high turbulence, typical of built environment wind conditions, generated higher loads than the ones predicted by the standard. Still, these results were considered complaint with the standard due to the large safety factor set for this load calculation methodology. However, these safety factors were considered to be not too informative or precise, limiting the validity of the simplified load model as a good load calculation method for the safe design of a small wind turbine.Aerospace Engineerin
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
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