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Torrejón de Ardoz, Spain

Mora R.B.,INTA
The Scientific World Journal | Year: 2014

Helicopters operations on board ships require special procedures introducing additional limitations known as ship helicopter operational limitations (SHOLs) which are a priority for all navies. This paper presents the main results obtained from the experimental investigation of a simple frigate shape (SFS) which is a typical case of study in experimental and computational aerodynamics. The results obtained in this investigation are used to make an assessment of the flow predicted by the SFS geometry in comparison with experimental data obtained testing a ship model (reduced scale) in the wind tunnel and on board (full scale) measurements performed on a real frigate type ship geometry. © 2014 Rafael Bardera Mora. Source


Giovannelli F.,National institute for astrophysics | Sabau-Graziati L.,INTA
Revista Mexicana de Astronomia y Astrofisica: Serie de Conferencias | Year: 2014

In this paper we will briefly discuss several examples of results, from the Big Bang to galactic sources, obtained in different frequency regions by many space-and ground-based experiments. We will remark the fundamental problems born from a comparison of experimental multifrequency results and theories. We will discuss also the importance of having a network of robotic telescopes that can provide long term optical monitoring of different classes of cosmic sources for providing fundamental data for a progress in understanding many problems still open. The results selected are biased by our knowledge and feelings and extend over several decades, starting from the 1970's, when the space experiments opened practically all the windows for investigating the Universe, up to-date. We discussed about this topic many times (e.g. on the review paper "The impact of the space experiments on our knowledge of the physics of the Universe" (Giovannelli & Sabau-Graziati, 2004) and subsequent revisions (e.g. Giovannelli & Sabau-Graziati, 2012a). Source


Giovannelli F.,Istituto di Astrofisica Spaziale e Fisica Cosmica | Sabau-Graziati L.,INTA
Memorie della Societa Astronomica Italiana, Supplementi - Journal of the Italian Astronomical Society, Supplement | Year: 2010

In occasion of the Silver Jubilee of the Frascati Workshop about Multifrequency Behaviour of High Energy Cosmic Sources we want to discuss some aspects of the Multifrequency Astrophysics. Multifrequency Astrophysics can be considered as a 'new field' of astrophysics born just around the end of 1970-ies - beginning of 1980-ies to which we strongly contributed not only with our own measurements and studies of physical processes spread along the whole electromagnetic spectrum, but mostly with the organization of the Frascati Workshop Series. In this paper we discuss the methodology used in astrophysics for collecting data coming from multifrequency observations of cosmic sources - obtained in different ways - and the relative models developed through theoretical study of physical processes governing their behaviour. Several examples about X-ray binaries, cataclysmic variables, T Tauri stars, relativisticjets from different classes of sources, gamma-ray bursts, and few words about Standard Big Bang Cosmology and experimental proofs fitting the theory will be discussed. We will briefly discuss also the prospects of the multifrequency astrophysics which is now in its golden age without any pretension of completness. © SAIt 2010. Source


Mora R.B.,INTA
Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering | Year: 2014

This paper presents the main results of the test campaign performed on a frigate ship model in a low-speed wind tunnel in order to investigate the ship superstructure airwake by means of particle image velocimetry (PIV). On board wind velocities measurements above the flight deck were carried out by a sonic anemometer and results were compared with these obtained in wind tunnel tests, providing information about the influence of the ship environment on the helicopter safe operational limitations during launch and recovery operations. The first step in the helicopter-ship qualification program is determine the wind limitations in order to build a candidate launch and recovery wind envelope. Thus subsequent steps of the program, additional effects produced by the helicopter rotor and ship motion must be evaluated, and finally flight trial on the ship must be performed to evaluate the pilot workload. © © IMechE 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav. Source


Diaz-Michelena M.,INTA | Cobos P.,Technical University of Madrid | Aroca C.,Technical University of Madrid
Sensors and Actuators, A: Physical | Year: 2015

Anisotropic magnetoresistive (AMR) magnetic sensors are often chosen as the magnetic transducer for magnetic field sensing in applications with low to moderate magnetic field resolution because of the relative low mass of the sensor and their ease of use. They measure magnetic fields in the order of the Earth magnetic field (with typical sensitivities of 1‰/G or 10-2‰/μT), have typical minimum detectable fields in order of nT and even 0.1 nT but they are seriously limited by the thermal drifts due to the variation of the resistivity with temperature (∼2.5‰/°C) and the variation of the magnetoresistive effect with temperature (which affects both the sensitivity of the sensors: ∼2.7‰/°C, and the offset: ±0.5‰/°C). Therefore, for lower magnetic fields, fluxgate vector sensors are generally preferred. In the present work these limitations of AMR sensors are outlined and studied. Three methods based on lock-in amplifiers are proposed as low noise techniques. Their performance has been simulated, experimentally tested and comparatively discussed. The developed model has been also used to derive a technique for temperature compensation of AMR response. The final goal to implement these techniques in a space qualified applied specific integrated circuit (ASIC) for Mars in situ exploration with compact miniaturized magnetometers. © 2014 Elsevier B.V. All rights reserved. Source

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