1,720,962 research outputs found
Resonant Enhancement of Standing Magnetoelastic Waves By Laser-generated Thermoelastic Waves In Ribbons of Metallic-glass
No full textExperimental evidence of magneto-elastic wave amplitude enhancement by thermo-elastic waves is reported. This enhancement is shown to be optimized under resonance conditions. The thermo-elastic waves have been excited in a metal alloy ribbon sample by a high repetition rate CO2 laser. The results are explained in terms of a simple theoretical treatment of the thermo-magnetic elastic waves under the conditions investigated
THE VIBRATIONAL-TRANSLATIONAL RELAXATION OF CF2HCL IN ARGON
No full textWe report in this paper results concerning the vibrational-translational (VT) rates of CF2HCl diluted in Ar as a neutral buffer. The dependence on the buffer concentration and on the initial vibrational energy distribution are obtained by using the 9R(48) and the 9R(34) CO, laser lines for the excitation process. The differences observed between the results corresponding to the two lines bear valuable information about the dependence of the VT relaxation process on the specific initial conditions of vibrational excitation
New materials and related fabrication processes for hot structures on RLV'S
No full textThe next generation of Reusable Launch Vehicles (RLV's) will implement the substitution of traditional blunt bodies with new aerodynamic configurations characterized by slender profiles with sharp leading edges. The main advantage of this redesign of hypersonic space vehicle is represented by enhanced maneuverability and improved cross range capability and consequently increased mission safety, In addition the reduction of wave drag in the ascent phase will reduce the costs of the payload deployment. The real possibility to adopt sharp profiles is strictly related to the selection and availability of materials with suitable performance. In fact at hypersonic speeds, sharp edges of slender configurations reach values of the surface temperatures much higher than any temperature allowable by traditional thermal protection system (TPS) and more the geometrical radius of curvature decreases, more the heat flux at leading edge increases. Recent research and developments of a new class of materials named Ultra High Temperature Ceramics (UHTC) seems to offer the right chance to fabricate hot structures for RLV's applications which can withstand temperatures above 2000°C. This paper deals with a new process technology based on the employment of zirconium diborides ceramic matrix composites that appropriately modified and reinforced can be considered, as our previous numerical investigation showed, very promising candidate materials for the fabrication of hot structures of slender bodies such as nose cap, wing leading edges, etc. The materials developed in the frame of a consistent scientific collaboration coordinated by CIRA, and involving Centre Sviluppo Materiali SpA (CSM) and University of Rome "La Sapienza", have been thermally and mechanically characterized in order to assess their applicability to a specific space mission requirements. Copyright © 2003 by the International Astronautical Federation. All rights reserved
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
Electromagnetic SQUID based NDE: a comparison between experiments and numerical FEM modelling
No full textin pres
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
Electromagnetic SQUID based NDE: a comparison between experiments and numerical FEM modelling
No full textin pres
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