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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.

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.

Egli L.,World Radiation Center | Grobner J.,World Radiation Center | Hulsen G.,World Radiation Center | Bachmann L.,University of Sao Paulo | And 8 more authors.
Atmospheric Measurement Techniques | Year: 2016

The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance measurements. Within the European EMRP ENV03 project ĝ€œSolar UVĝ€, new devices, guidelines and characterization methods have been developed to improve solar UV measurements with ASRMs, and support to the end user community has been provided. In order to assess the quality of 14 end user ASRMs, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the blind intercomparison revealed that ASRMs, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema-weighted UV index - in particular at large solar zenith angles - due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available ASRMs within 5ĝ€% compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range of solar zenith angles. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 and 400ĝ€nm under all atmospheric conditions. © Author(s) 2016.

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.

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.

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