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Nanoaluminum as a Solid Propellant Fuel
No full textExperimental studies on the burning of nanoaluminum-based solid rocket propellants are carried out. Data on the properties of condensed combustion products, mechanisms of their formation, and burning-rate law are obtained.
Based on these data, a physical picture is developed of the considered burning-propellant classes. Mathematical modeling of burning nanoaluminum in composite solid rocket propellants is carried out. The influence of nanoaluminum on ignition temperature of the metal fuel and burning-rate law is shown. The results of this study allow carrying out the analysis and selection of good-quality propellants using nanoaluminum
Condensed Combustion Products from Burning of Nanoaluminum Based Propellants: Properties and Formation Mechanism
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Metallized Dual-Oxidizer Solid Propellants for Green Space Access
No full textOwing to technology maturity, simplicity, and reliability, in the near future (2010-2020) solid rocket propulsion will continue to play a main role in the development of Expendable Launch Vehicles (ELV's), both as first stages of heavy launchers and main stages of small/medium launchers. In this context, a cooperation was started between Avio and Politecnico di Milano - SPLab addressed to the study of Ammonium Nitrate - based composite rocket propellant combustion. The objective is to identify an optimum AN+AP dual oxidizer system and understand its basic combustion properties in view of possible space propulsion applications
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
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
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