86,520 research outputs found
Development of a Counterbalanced Pendulum Thrust Stand for Electric Propulsion
No full textWe have designed and tested a thrust stand for RF plasma thrusters characterization. The balance is employed in the development of small and medium size RF plasma thrusters; it allows for a high number of tests per day with an accuracy in the order of 10%. The balance relies on the counterbalanced-type pendulum concept, which allows adjusting the instrument sensibility without changing the overall pendulum size. The range of thrust which can be evaluated depends on the mass of the prototype under test; e.g. for a 0.5 kg prototype the thrust can vary from 20 μN up to 50 mN. The system can be calibrated with both a calibration mass, and an electric calibrator. We have developed an algorithm which corrects the thermal drifts generated during thruster operation. We have compared the stand results against Faraday cup measurements, finding an agreement within 20%
L-band Plasma Turnstile Antenna for GPS applications
No full textThis work presents the preliminary results of a crossed dipole antenna that works in the L-band and that exploits plasma technology to generate and receive a circularly polarized electromagnetic field. The study considered in a first stage a simplified plasma crossed dipole and successively it included a more realistic design that comprises the plasma generation equipment, more realistic glass vessels and the electrodes used to generate the plasma. The simplified design can achieve good results in terms of axial ratio (i.e., circular polarization), directivity, and input impedance if compared to its metallic counterpart. However, when the more realistic antenna is considered, a down-shift in the operation frequency can be observed. Furthermore, the influence of the plasma parameters on the antenna parameters has been analyzed. All the results have been obtained through full-wave numerical simulations in CST Microwave Studio
Variations on the Author
No full text“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
Design of a thrust balance for RF plasma thruster characterization2014 IEEE Metrology for Aerospace (MetroAeroSpace)
No full text[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
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