1,720,954 research outputs found
Electrical power aspects of distributed propulsion systems in turbo-electric powered aircraft
Get PDFThe aerospace industry is currently looking at options for fulfilling the
technological development targets set for the next aircraft generations.
Conventional engines and aircraft architectures are now at a maturity level
which makes the realisation of these targets extremely problematic. Radical
solutions seem to be necessary and Electric Distributed Propulsion is the most
promising concept for future aviation. Several studies showed that the viability
of this novel concept depends on the implementation of a superconducting
power network.
The particularities of a superconducting power network are described in this
study where novel components and new design conditions of these networks
are highlighted. Simulink models to estimate the weight of fully superconducting
machines have been developed in this research work producing a relatively
conservative prediction model compared to the NASA figures which are the only
reference available in the literature. A conceptual aircraft design architecture
implementing a superconducting secondary electrical power system is also
proposed. Depending on the size of the aircraft, and hence the electric load
demand, the proposed superconducting architecture proved to be up to three
times lighter than the current more electric configurations. The selection of such
a configuration will also align with the general tendency towards a
superconducting network for the proposed electric distributed propulsion
concept. In addition, the hybrid nature of these configurations has also been
explored and the potential enhanced role of energy storage mechanisms has
been further investigated leading to almost weight neutral but far more flexible
aircraft solutions. For the forecast timeframe battery technology seems the only
viable choice in terms of energy storage options. The anticipated weight of the
Lithium sulphur technology is the most promising for the proposed architectures
and for the timeframe under investigation. The whole study is based on
products and technologies which are expected to be available on the 2035
timeframe. However, future radical changes in energy storage technologies may be possible but the approach used in this study can be readily adapted to meet
such changes.PhD in Manufacturin
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
Future energy storage solutions for hybrid-electric powered aircraft
No full textThis paper is part of the conference proceedings from the 22nd International Symposium on Air Breathing Engines
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
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