Time filter

Source Type

Fornet-Ruiz J.,Instituto Nacional Of Tecnica Aeroespacial Inta | Lozano-Guerrero A.,Technical University of Cartagena | Monzo-Cabrera J.,Technical University of Cartagena | Diaz-Morcillo A.,Technical University of Cartagena
IEEE MTT-S International Microwave Symposium Digest | Year: 2011

A broadband primary standard for thermal noise measurements is presented and its thermal and electromagnetic behavior is analyzed by means of analytical and numerical simulation techniques. It consists of a broadband termination connected to a 3.5mm coaxial airline partially immersed in liquid Nitrogen. The main innovative part of the device is the thermal bead between inner and outer conductors, designed for obtaining a proper thermal contact and to keep low both its contribution to the total thermal noise and its reflectivity. A sensitivity analysis is realized in order to fix the manufacturing tolerances for a proper performance in the range 10MHz-26.5GHz. © 2011 IEEE.


Delgado F.J.,Polytechnic University of Valencia | Ortega P.,Polytechnic University of Catalonia | Tarrida C.L.,Polytechnic University of Valencia | Garcia J.,Polytechnic University of Valencia | And 2 more authors.
Proceedings of IEEE Sensors | Year: 2010

This paper shows the design and calibration of an improved miniaturized two-axis sun sensor for satellite attitude control. The proposed new structure is based on a previous sun sensor structure by adding multiple sensing cells. The improvement in precision is obtained by the subdivision of field of view (FoV), which is expected to be ±60°, with a resolution of 0.1°. In the paper, both the mathematical model and the experimental results are presented. The resulting device will be incorporated in Microsat satellite from INTA, which will be launched in 2012. ©2010 IEEE.


Lozano C.,Instituto Nacional Of Tecnica Aeroespacial Inta | Andres E.,Instituto Nacional Of Tecnica Aeroespacial Inta | Martin M.,Instituto Nacional Of Tecnica Aeroespacial Inta | Bitrian P.,Instituto Nacional Of Tecnica Aeroespacial Inta
International Journal for Numerical Methods in Fluids | Year: 2012

This paper considers the computation of flow sensitivities that arise in the context of design optimization. The scheme is based on the solution of a continuous adjoint problem, for which two complementary, although analytically equivalent, approaches have been routinely used for some time now, yielding expressions for the sensitivities that contain, respectively, boundary and domain integrals. These concepts are clarified in a unified framework and their equivalence at the continuous level is demonstrated through appropriate algebraic manipulations. Equivalence at the discrete level is assessed through numerical testing for various aerodynamic shape-optimization problems. © 2011 John Wiley & Sons, Ltd.


Gonzalez E.L.,Instituto Nacional Of Tecnica Aeroespacial Inta | Llerena F.I.,Instituto Nacional Of Tecnica Aeroespacial Inta | Perez M.S.,Instituto Nacional Of Tecnica Aeroespacial Inta | Iglesias F.R.,University of Seville | Macho J.G.,University of Seville
International Journal of Hydrogen Energy | Year: 2015

Storage of electricity from renewable energy sources is one of the main challenges to be overcome to ensure a proper integration of renewable technologies into the power grid, paving the way for their gradual introduction into future energy scenarios. The use of hydrogen as an energy carrier is a potential and promising option among the different technologies that can be used to store electrical energy from renewable sources on a large scale. Typical hydrogen facilities used to store renewable electricity are currently based on electrolysis systems connected to the power source, mainly wind or photovoltaic. Hydrogen is stored in accordance with the facility requirements for its use in stationary fuel cells for electric power production. This article presents the evaluation, in terms of energy-related parameters, of a hydrogen storage system, connected to a renewable energies power plant. The system is located at INTA R&D facilities in Huelva, SW of Spain. These parameters will be representative of the real performance of the system, and can be used as indicators to compare different electrical energy storage systems based on hydrogen and other technologies. Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Andrey J.,Instituto Nacional Of Tecnica Aeroespacial Inta | Cuevas E.,Izana Atmospheric Research Center | Parrondo M.C.,Instituto Nacional Of Tecnica Aeroespacial Inta | Alonso-Perez S.,Izana Atmospheric Research Center | And 3 more authors.
Atmospheric Environment | Year: 2014

Ozone (O3) reduction caused by dust particles is a challenging topic that has not been sufficiently investigated. Previous studies have provided limited quantification of O3, mainly based on case studies or short-term campaigns. In this paper, 157 O3 vertical profiles from ozone soundings launched from the Canary Islands over 13 summers are analyzed. Using aerosol optical depth as a discrimination tool, the data are classified into two groups: clean atmospheric conditions and dusty conditions under the presence of the Saharan Air Layer (SAL). The results show that ozone mixing ratios on SAL days are systematically lower than those during clean conditions, with a difference of as much as 35%. An analysis of independent total ozone columns from ground-based and satellite spectrometers confirm the observed O3 reductions. In addition, a vertical redistribution of the total water content takes place during these events. A comparison of the vertical shape of the O3 reductions with the vertical distribution of dust loading and precipitable water vapor shows that although O3 reductions occur in parts of the layer where the dust is present, a better correlation is found with the total amount of water present in the air. This finding suggests that the latter component plays a role in the observed O3 reduction within the SAL. © 2013 Elsevier Ltd.


Villanueva F.,University of Castilla - La Mancha | Notario A.,University of Castilla - La Mancha | Adame J.A.,Instituto Nacional Of Tecnica Aeroespacial Inta | Millan M.C.,University of Castilla - La Mancha | And 2 more authors.
Environmental Technology (United Kingdom) | Year: 2013

We report the first observations of volatile organic compound (VOC) concentrations, including aldehydes, in the coastal, industrial area of Huelva near the Doñana National Park (south-west of the Iberian Peninsula). The periods studied were July-September 2008 and February-November 2009. Formaldehyde, acetaldehyde, acetone, propanal, benzene, toluene and m/p-xylenes were identified and quantified. Acetone and formaldehyde were the most abundant carbonyls, followed by acetaldehyde and propanal. Maximum and minimum values for all these compounds in the period of measurement, and their relationship with meteorological parameters or influence of anthropogenic or biogenic emissions, are analysed. Finally, different concentration ratios and correlations were calculated to assess the effect of the anthropogenic or biogenic processes on the observed VOC levels. © 2013 Copyright Taylor and Francis GRouép, LLC.


Adame J.A.,Instituto Nacional Of Tecnica Aeroespacial Inta | Cordoba-Jabonero C.,Instituto Nacional Of Tecnica Aeroespacial Inta | Sorribas M.,University of Granada | Toledo D.,Instituto Nacional Of Tecnica Aeroespacial Inta | Gil-Ojeda M.,Instituto Nacional Of Tecnica Aeroespacial Inta
Atmospheric Environment | Year: 2015

A research campaign was performed for the AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry) project at El Arenosillo observatory (southwest Spain) in May-June 2012. The campaign focused on the impact of Saharan dust intrusions at the atmospheric boundary layer (ABL) and ozone-aerosol interactions. In-situ and remote-sensing techniques for gases and aerosols were used in addition to modelling analyses. Meteorology features, ABL structures and evolution, aerosol profiling distributions and aerosol-ozone interactions on the surface were analysed. Two four-day periods were selected according to non-dusty (clean conditions) and dusty (Saharan dust) situations. In both scenarios, sea-land breezes developed in the lower atmosphere, but differences were found in the upper levels. Results show that surface temperatures were greater than 3°C and humidity were lower during dusty than non-dusty conditions. Thermal structures on the surface layer (estimated using an instrument on a 100m tower) show differences, mainly during nocturnal periods with less intense inversions under dusty conditions. The mixing layer during dusty days was 400-800m thick, less than observed on non-dusty. Dust also disturbed the typical daily ABL evolution. Stable conditions were observed in the early evening during intrusions. Aerosol extinction on dusty days was 2-3 times higher, and the dust was confined between 1500 and 5500m. Back trajectory analyses confirmed that the dust had an African origin. On surface, the particle concentration was approximately 3.5 times higher during dusty events, but the local ozone did not exhibit any change. The arrival of Saharan dust in the upper levels impacted the meteorological surface, inhibited the daily evolution of the ABL and caused an increase in aerosol loading on the surface and at higher altitudes; however, no dust influence was observed on the surface ozone. © 2015 Elsevier Ltd.


Zuluaga-Ramirez P.,Instituto Nacional Of Tecnica Aeroespacial Inta | Zuluaga-Ramirez P.,Technical University of Madrid | Frovel M.,Instituto Nacional Of Tecnica Aeroespacial Inta | Belenguer T.,Instituto Nacional Of Tecnica Aeroespacial Inta | Salazar F.,Technical University of Madrid
Materials | Year: 2015

This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to "dog bone" shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. © 2015 by the authors.


Feo A.,Instituto Nacional Of Tecnica Aeroespacial Inta | Vargas M.,NASA | Sor S.,Instituto Nacional Of Tecnica Aeroespacial Inta
SAE Technical Papers | Year: 2011

This work presents the development of a Rotating Rig Facility by the Instituto Nacional de Técnica Aeroespacial (INTA) in cooperation with the NASA Glenn Research Center. The facility is located at the INTA installations near Madrid, Spain. It has been designed to study the deformation, breakup and impact of large droplets induced by aerodynamic bodies. The importance of these physical phenomena is related to the effects of Supercooled Large Droplets in icing clouds on the impinging efficiency of the droplets on the body, that may change should these phenomena not be taken into account. The important variables and the similarity parameters that enter in this problem are presented. The facility's components are described and some possible set-ups are explained. Application examples from past experiments are presented in order to indicate the capabilities of the new facility. Copyright © 2011 SAE International.


PubMed | Instituto Nacional Of Tecnica Aeroespacial Inta and Technical University of Madrid
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2015

We present an optical sensing methodology to estimate the fatigue damage state of structures made of carbon fiber reinforced polymer (CFRP), by measuring variations on the surface roughness. Variable amplitude loads (VAL), which represent realistic loads during aeronautical missions of fighter aircraft (FALSTAFF) have been applied to coupons until failure. Stiffness degradation and surface roughness variations have been measured during the life of the coupons obtaining a Pearson correlation of 0.75 between both variables. The data were compared with a previous study for Constant Amplitude Load (CAL) obtaining similar results. Conclusions suggest that the surface roughness measured in strategic zones is a useful technique for structural health monitoring of CFRP structures, and that it is independent of the type of load applied. Surface roughness can be measured in the field by optical techniques such as speckle, confocal perfilometers and interferometry, among others.

Loading Instituto Nacional Of Tecnica Aeroespacial Inta collaborators
Loading Instituto Nacional Of Tecnica Aeroespacial Inta collaborators