1,720,960 research outputs found
Quasi-steady aeroelastic analysis of the semi-aeroelastic hinge including geometric nonlinearities
No full textA recent consideration in aircraft design is the use of folding wingtips, with the aim of enabling higher-aspect-ratio wings with less induced drag but also meeting airport gate limitations. A formulation is introduced to account for finite rotations of rigid folding wingtips attached through hinges on a flexible airframe structure including also aerodynamic follower forces for the folding wingtip components. This study investigates the effects of geometric nonlinearities on the quasi-steady aeroelastic response of floating wingtips. It is found that the wingtip response can vary significantly when geometric nonlinearities are accounted for; however, a small impact was observed on the main airframe structure
Aeroelastics flight dynamics coupling effects of the semi-aeroelastic hinge device
No full textA recent consideration in aircraft design is the use of folding wingtips, with the aim of enabling higher-aspect-ratio aircraft with less induced drag but also meeting airport gate limitations. This study investigates the impact of floating folding wingtips on the aircraft flight dynamics. It is found that a floating wingtip aircraft has similar handling qualities with respect to an aircraft with no wing extension
Unsteady aeroelastic analysis of the semi aeroelastic hinge including local geometric nonlinearities
No full textA recent consideration in aircraft design is the use of folding wing tips, with the aim of enabling higher aspect ratio wings with less induced drag but also meeting airport gate limitations. Of particular interest is the concept of using in flight free floating wing tips in order to reduce aircraft gust and maneuver loads. This study investigates the effects of local geometric nonlinearities on the static response, dynamic stability, post flutter behaviour and gust response of floating wing tips. A multibody formulation is introduced to account for finite rotations of rigid folding wing tips attached through hinges on a flexible airframe structure including also aerodynamic follower forces for the folding wing tip components. It is found that the wing tip response can vary significantly when geometric nonlinearities are accounted for; the post flutter behaviour is characterised by super-critical limit cycle oscillations and no sub-critical instability was observed for the analysed cases. Moreover, the wing tip gust response can vary significantly when geometric nonlinearities are accounted for whereas a small impact was observed on the main airframe structure
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
Aeroelastic behaviour of hinged wing tips
No full textThe primary purpose of a hinged wing tip on an airliner aircraft is to allow an aerodynamically efficient high aspect ratio wing to enter an airport gate of standard dimensions. There exists a potential opportunity to allow a wing tip to move in flight to alleviate the loads and achieve a lower wing weight. This paper will provide a summary of the latest studies investigating the Aeroelastic behaviour (loads and flutter) of hinged wing tips
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
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