Person: Vázquez Martínez, Luis
Universidad Complutense de Madrid
Faculty / Institute
Análisis Matemático Matemática Aplicada
Now showing 1 - 9 of 9
PublicationLa aventura de la exploración de Marte(2013-04-18) Vázquez Martínez, LuisResumen La exploración del planeta Marte forma parte de un objetivo científico de largo alcance: entender la formación y la historia del Sistema Solar, saber no sólo cómo son hoy en día todos los cuerpos celestes que lo forman, sino cómo fueron en otros tiempos geológicos, cómo se formaron, si en ellos se dieron condiciones para que se desarrollase vida como ocurrió en la Tierra. En este contexto científico se ha de resaltar la participación activa de la Universidad Complutense de Madrid. Asunto que se aborda con el siguiente esquema: 1. Exploración de Marte. Aspectos generales de Marte 2. Principales descubrimientos de la exploración de Marte 3. Misiones a Marte 4. Entorno de estudios marcianos en la Universidad Complutense de Madrid 5. Referencia de futuro 6. Ejemplos básicos de estudio y modelización: • Radiación solar ultravioleta en la superficie marciana • Capa límite de Marte • Eclipses de Fobos PublicationMOURA magnetometer for Mars MetNet Precursor Mission. Its potential for an in situ magnetic environment and surface characterization(Universidad Complutense de Madrid, Servicio de publicaciones, 2016) Herraiz Sarachaga, Miguel; Vázquez Martínez, Luis; Díaz Michelena, Marina; Sanz, Ruy; Fernández, Ana Belén; Manuel, Víctor de; Cerdán Cojedor, Miguel Felipe; Apestigue, Víctor; Arruego, Ignacio; Azcue, JoaquínMOURA magnetometer and gradiometer is part of the scientific instrumentation for Mars MetNet Precursor mission. This work describes the objective of the investigation, summarizes the work done in the design and development of the sensor as well as its calibration, and shows the demonstration campaigns to show the potential of such instrument for planetary landers and rovers. PublicationCharacterization of the Martian Surface Layer(American Meteorological Society, 2009-01) Martínez, Germán; Valero Rodríguez, Francisco; Vázquez Martínez, LuisWe have estimated the diurnal evolution of Monin- Obukhov length, friction velocity, temperature scale, surface heat flux, eddy-transfer coefficients for momentum and heat, and turbulent viscous dissipation rate on the Martian surface layer for a complete Sol belonging to the Pathfinder mission. All these magnitudes have been derived from in situ wind and temperature measurements at around 1.3 m height, and simulated ground temperature (from 6 a.m. Sol 25 to 6 a.m. Sol 26). Up to the moment, neither values of turbulent viscous dissipation rate and eddy-transfer coefficients from in situ measurements for the Martian surface layer, nor diurnal evolutions of all the previous mentioned turbulent parameters for the Pathfinder had been obtained. Monin-Obukhov similarity theory for stratified surface layers has been applied to obtain the results. The values assigned to the surface roughness, and the applied parameterization of the interfacial sublayer will be discussed in detail due to the sensibility of the results on them. We have found similarities concerning the order of magnitude and qualitative behaviour of Monin- Obukhov length, friction velocity and turbulent vis-cous dissipation rate on Earth and on Mars. However, magnitudes directly related to the lower Martian atmospheric density and thermal inertia, like temperature scale and hence surface heat flux, show different order of magnitude. Finally, turbulent exchanges in the first meters have been found to be just two orders of magnitude higher than the molecular ones, while on Earth around five orders of magnitude separate both mechanisms. PublicationCharacterization of the Martian Convective Boundary Layer(American Meteorological Society, 2009-07) Martínez, Germán; Valero Rodríguez, Francisco; Vázquez Martínez, LuisThe authors have carried out an extensive characterization of the Martian mixed layer formed under convective conditions. The values of the mixed layer height, convective velocity scale, convective temperature scale, mean temperature standard deviation, mean horizontal and vertical velocity standard deviations, and mean turbulent viscous dissipation rate have been obtained during the strongest convective hours for the mixed layer. In addition, the existing database of the surface layer has been improved by recalculating some parameters (e.g., Monin–Obukhov length, friction velocity, or scale temperature) that had already been obtained in previous papers by other means and also by calculating new ones, such as the standard deviation of the vertical wind speed velocity, the turbulent viscous dissipation rate, and eddy transfer coefficients for momentum and heat. The Earth counterparts of all these magnitudes are also shown. In this paper, a comprehensive database concerning the whole convective planetary boundary layer on Mars is displayed, and a detailed terrestrial comparison is established. The inputs of this work are hourly in situ temperature, hourly in situ horizontal wind speed, and hourly simulated ground temperature for specific selected Sols of the Viking and Pathfinder landers. These data correspond to typical low and midlatitude northern summertime conditions, with weak prevailing winds. To handle this set of data, surface layer and mixed layer similarity theory have been used at the strongest convective hours. In addition, the inclusion of a parameterization of a molecular sublayer and prescribed values of the surface roughness has been considered. PublicationA dynamics approach to the computation of eigenvectors of matrices(Science Press, 2005-11) Jiménez , S.; Vázquez Martínez, LuisWe construct a family of dynamical systems whose evolution converges to the eigenvectors of a general square matrix, not necessarily symmetric. We analyze the convergence of those systems and perform numerical tests. Some examples and comparisons with the power methods are presented. PublicationAbout Some Possible Implementations of the Fractional Calculus(https://mdpi.com, 2020) Velasco, María Pilar; Usero, David; Jiménez, Salvador; Vázquez Martínez, Luis; Vázquez Poletti, José Luis; Mortazavi, MinaWe present a partial panoramic view of possible contexts and applications of the fractional calculus. In this context, we show some different applications of fractional calculus to different models in ordinary differential equation (ODE) and partial differential equation (PDE) formulations ranging from the basic equations of mechanics to diffusion and Dirac equations. PublicationAn interpolation between the wave and diffusion equations through the fractional evolution equations Dirac like(American Institute of Physics, 2005) Pierantozzi, Teresa; Vázquez Martínez, LuisThrough fractional calculus and following the method used by Dirac to obtain his well-known equation from the Klein-Gordon equation, we analyze a possible interpolation between the Dirac and the diffusion equations in one space dimension. We study the transition between the hyperbolic and parabolic behaviors by means of the generalization of the D’Alembert formula for the classical wave equation and the invariance under space and time inversions of the interpolating fractional evolution equations Dirac like. Such invariance depends on the values of the fractional index and is related to the nonlocal property of the time fractional differential operator. For this system of fractional evolution equations, we also find an associated conserved quantity analogous to the Hamiltonian for the classical Dirac case. PublicationSpectral information retrieval from integrated broadband photodiode UV measurements(Alan E. Willner, University of Southern California, 2007) Vázquez Martínez, Luis; Zorzano, María Paz; Jiménez, SalvadorWe propose an algorithm to retrieve the global features of the spectral dependence of the ultraviolet (UV) irradiance from integrated, broadband UV measurements performed with a set of photodiodes with different UV filters. This fit, when applied to ground based measurements and compared to the incident Solar spectral irradiance on the top of the atmosphere, may be used to extract the spectral dependence of the UV opacity and the most relevant parameters characterizing the scattering with atmospheric aerosol (Angstrom exponent, etc) as well as the biological effective doses. In this way, using a set of photodiodes instead of a spectrophotometer, one may get spectral information within very low mass, package and weight constraints, which is particular useful for space missions. We consider its application for the rover-based exploration of the Martian ground which is subjected to daily and seasonal opacity variations. PublicationOpportunities to observe solar eclipses by Phobos with the Mars Science Laboratory(Wiley, 2012-11) Barderas, Gonzalo; Romero Pérez, Mª Pilar; Vázquez Martínez, Luis; Vázquez Poletti, José Luis; Llorente, I. M.We have generated predictions for observing Phobos transits during the period 2012–2014 using the Mars Science Laboratory. We describe how the detections of Phobos eclipses can be used as an alternative procedure to determine the coordinates of the rover. We present a numerical simulation to analyse the sensitivity of the precise observed contact times to the coordinate determination. The numerical results show that after four days of eclipse observations for 1 min each day, within the 25 × 20 km2 landing site ellipse, the position of the lander can be determined to within an ellipse of 40 × 60 m2 for uncertainties of 1 s in eclipse time observations. A 20 × 15 m2 ellipse is estimated if a 0.1-s time precision can be gathered.