30 resultados para Dudrid, Cristobal

em Universidad Politécnica de Madrid


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The determination of the Stark broadening parameters of Sn ions is useful for astrophysicists interested in the determination of the density of electrons in stellar atmospheres. In this paper, we report on the calculated values of the Stark broadening parameters for 171 lines of Sn iii arising from 4d105sns (n= 6–9), 4d105snp (n= 5, 6), 4d105p2, 4d105snd (n= 5–7), 4d105s4f and 4d105s5g. Stark linewidths and line shifts are presented for an electron density of 1023 m−3 and temperatures T= 11 000–75 000 K. These have been calculated using a semi-empirical approach, with a set of wavefunctions obtained from Hartree–Fock relativistic calculations, including core polarization effects. The results obtained have been compared with available experimental data. These can be used to consider the influence of Stark broadening effects in A-type stellar atmospheres

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Transitionprobabilities and oscillatorstrengths of 176 spectral lines with astrophysical interest arising from 5d10ns (n = 7,8), 5d10np (n = 6,7), 5d10nd (n = 6,7), 5d105f, 5d105g, 5d10nh (n = 6,7,8), 5d96s2, and 5d96s6p configurations, and radiativelifetimes for 43 levels of PbIV, have been calculated. These values were obtained in intermediate coupling (IC) and using relativistic Hartree–Fock calculations including core-polarization effects. For the IC calculations, we use the standard method of least-square fitting from experimental energy levels by means of the Cowan computer code. The inclusion in these calculations of the 5d107p and 5d105f configurations has facilitated a complete assignment of the energy levels in the PbIV. Transitionprobabilities, oscillatorstrengths, and radiativelifetimes obtained are generally in good agreement with the experimental data.

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A straightforward unprecedented sublimation protocol that reveals both conversion of a racemic compound into a racemic conglomerate and subsequent enantioenrichment has been developed for the proteinogenic amino acid valine. The phenomenon has been observed in closed and open systems, providing insight into asymmetric amplification mechanisms under presumably prebiotic conditions

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Transports of radioactive wastes in Spain are becoming issues of renewed interest, due to the increased mobility of these materials which can be expected after the building and operation of the planned central repository for this country in a near future. Such types of residues will be mainly of the medium and high activity classes and have raised concerns on the safety of the operations, the radiological protection of the individuals, the compliance with the legal regulations and their environmental consequences of all kind. In this study, relevant information for the assessment of radiological risk of road transport were taken into account, as the sources and destination of the radioactive transports, the amount of traveling to be done, the preferred routes and populations affected, the characterization of the residues and containers, their corresponding testing, etc. These data were supplied by different organizations fully related with these activities, like the nuclear power stations, the companies in charge of radioactive transports, the enterprises for inspection and control of the activities, etc., as well as the government institutions which are responsible for the selection and location of the storage facility and other decisions on the nuclear policies of the country. Thus, we have developed a program for computing the data in such a form that by entering the radiation levels at one meter of the transport loads and by choosing a particular displacement, the computer application is capable to calculate the corresponding radiological effects, like the global estimated impact, its relevance to the population in general or on those people living and driving near the main road routes, the doses received by the most exposed individuals (e.g. the workers for loading or driving the vehicle), or the probability of detrimental on the human health. The results of this work could be of help for a better understanding and management of these activities and their related impacts; at the same time that the generated reports of the computer application are considered of particular interest as innovative and complementary information to the current legal documentation, which is basically required for transporting radioactive wastes in the country, according with the international safety rules (like IAEA and ADR).Though main studies are still in progress, as the definite location for the Spanish storage facility has not been decided yet, preliminary results with the existing transports of residues of medium activity indicate that the radiological impact is very low in conventional operations. Nevertheless, the management of these transports is complex and laborious, making it convenient to progress further in the analysis and quantification of this kind of events, which constitutes one of the main objectives of the present study for the radioactive road mobility in Spain.

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Los aspectos relacionados con el transporte de residuos radiactivos de alta actividad (RAA) hacia el futuro almacén temporal centralizado (ATC) están de actualidad, por el propio trasiego que se espera en un futuro próximo, el compromiso adquirido de estas actividades con el medio ambiente, la seguridad de las personas [1], así como su normativa reguladora. En España se prevé una larga “ruta radiactiva” de más de 2.000 kilómetros, por la que el combustible nuclear gastado se transportará presumiblemente por carretera desde las centrales nucleares hasta el ATC, así como los residuos vitrificados procedentes del reprocesado del combustible de la central nuclear Vandellos I, que en la actualidad están en Francia. Proponemos como hipótesis el siniestro de uno de estos transportes con combustible nuclear gastado en una ruta definida y nos preguntamos: ¿Qué impacto radiológico se podría generar en el medio ambiente o en individuos tipo cercanos al siniestro, el público en general…?

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In this paper, we report calculated values of the Stark widths and shifts for 72 spectral lines of Pb v. They were calculated using the Griem semi-empirical approach. A set of wavefunctions obtained from Hartree–Fock relativistic calculations including core polarization effects was used. Stark widths and shifts corresponding to lines arising from 5d9ns (n = 7, 8), 5d9 6p, 5d9 6d and 5d9 5f configurations of Pb v. Stark widths and shifts are presented for an electron density of 1017 cm−3 and temperatures T = 1.6–5.0 (104 K). The 2142.5, 2167.9 and 2278.6 Å lines of Pb v recently measured are included in our calculations. In this case, we have included for comparison calculations without core polarization effects. There is good agreement between our calculations and the above-cited experimental values.

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Las cuestiones relacionadas con el transporte de residuos radiactivos de alta actividad, en adelante (RAA), al previsto almacén centralizado (ATC) constituyen un objeto de renovada actualidad, por la movilidad que se espera de estos materiales en un futuro próximo, por el compromiso creciente de estas actividades con el medio ambiente, por la seguridad y protección de las personas, así como por el actual marco legal [1]. Cabe preguntarse: ¿Cuáles serán las rutas más activas? ¿Qué impacto radiológico se generará en el medio ambiente o en individuos tipo, como los ocupantes de un vehículo particular o industrial que puedan coincidir con el transporte, en las poblaciones y el público en general … ? En España se prevé una larga “ruta radiactiva” de más de 2.000 kilómetros, por la que el combustible nuclear gastado se transportará presumiblemente por carretera desde las centrales nucleares hasta el ATC, así como los residuos vitrificados procedentes del reprocesado del combustible de la central nuclear Vandellos I, que en la actualidad están en Francia

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Técnicos de TECNATOM, S.A. e Investigadores de la (UPM), han desarrollado un programa para analizar la logística y los impactos potenciales del transporte por carretera de materiales radiactivos en España. El transporte de materiales radiactivos es un tema de renovado interés en nuestro país debido a la creciente movilidad que cabe esperar, sobre todo tras la entrada en operación del almacén temporal centralizado (ATC) previsto para los próximos años. Este almacén está destinado a residuos de alta actividad, principalmente combustibles gastados de las plantas nucleares españolas, que hasta ahora se han venido depositando en las propias instalaciones generadoras o se enviaban a Francia. Pero ninguna de ambas opciones resulta sostenible técnica o económicamente en el futuro, y de ahí la necesidad del nuevo (ATC)

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El presente documento evalúa la Cuenca Alta del Guadalquivir en busca de posibles estructuras viables como almacenes de CO2, tanto técnica como económicamente. Se lleva a cabo la selección de seis posibles estructuras, de las cuales solo tres han resultado viables atendiendo a criterios técnicos y socio-económicos. De estas tres, se evalúa la viabilidad económica de la de mayor capacidad, obteniendo como resultado que la capacidad estimada es demasiado baja para que sea rentable su uso como almacén de CO2 a nivel comercial en una industria tipo de la Unión Europea. Para ello nos basamos principalmente en la Ley 40/2010 que regula el almacenamiento geológico en nuestro país, el informe GeoCapacity elaborado por el IGME, atlas elaborados por el Departamento de Energía de los Estados Unidos (DOE), y en diversos documentos de carácter económico publicados a nivel Europeo. Este proyecto, está incluido dentro de la Cátedra TecFutura, y forma parte del proyecto AVANZACO2. Por tanto, ha contado con la colaboración de las empresas implicadas en dicho proyecto, Sacyr Vallehermoso y Gessal así como con investigadores de la UPM. En relación con dicho proyecto, se procesaron los datos obtenidos mediante la herramienta informática CO2SITEASSES. ABSTRACT This paper evaluates the Upper basin of the Guadalquivir in the search of viable structures for CO2 storage, both technically and economically. The selection of six possible structures has been made, of which only three have proved to be viable attending to technical an socio-economic criteria. Of these three, we evaluate the economic viability of the larger capacity. In result, the estimated capacity is too low to make it profitable for a commercial use. In order to do this, we rely primarily on the Law 40/2010, which regulate the geological storage in our country, the report GeoCapacity, prepared by the IGME, atlas prepared by de Department of Energy of the United States (DOE) and various economic papers published in Europe. This project is included in the “Cátedra TecFutura” and is part of AVANZACO2 project. Therefore it has enjoyed the cooperation of the companies involved in the project, Sacyr Vallehermoso and Gessal, as well as UPM researchers. Related to this project, the obtained data were processed using the software CO2SITEASSES

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Laser Shock Processing is developing as a key technology for the improvement of surface mechanical and corrosion resistance properties of metals due to its ability to introduce intense compressive residual stresses fields into high elastic limit materials by means of an intense laser driven shock wave generated by laser with intensities exceeding the 109 W/cm2 threshold, pulse energies in the range of 1 Joule and interaction times in the range of several ns. However, because of the relatively difficult-to-describe physics of shock wave formation in plasma following laser-matter interaction in solid state, only limited knowledge is available in the way of full comprehension and predictive assessment of the characteristic physical processes and material transformations with a specific consideration of real material properties. In the present paper, an account of the physical issues dominating the development of LSP processes from a moderately high intensity laser-matter interaction point of view is presented along with the theoretical and computational methods developed by the authors for their predictive assessment and new experimental contrast results obtained at laboratory scale.

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Outline: • Introduction • Fundamental Physics of the Laser-Plasma Interaction in Laser Shock Processing • Theoretical/Computational Model Description • Some Results. Analysis of Interaction Parameters • Experimental Validation. Diagnosis Setup • Discussion and Outlook

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We have determined matrix elements for all experimental configurations of Ca III, including the 3s3p63d configuration. These values have been obtained using intermediate coupling (IC). For these IC calculations, we have used the standard method of least-squares fitting from the experimental energy levels, using the computer code developed by Robert Cowan. In this paper, using these matrix elements, we report the calculated values of the Ca III Stark widths and shifts for 148 spectral lines, of 56 Ca III spectral line transition probabilities and of eight radiative lifetimes of Ca III levels. The Stark widths and shifts, calculated using the Griem semi-empirical approach, correspond to the spectral lines of Ca III and are presented for an electron density of 1017 cm?3 and temperatures T = 1.0?10.0 (×104 K). The theoretical trends of the Stark broadening parameter versus the temperature are presented for transitions that are of astrophysical interest. There is good agreement between our calculations, for transition probabilities and radiative lifetimes, and the experimental values presented in the literature. We have not been able to find any values for the Stark parameters in the references.

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In the present work we report theoretical Stark widths and shifts calculated using the Griem semi-empirical approach, corresponding to 237 spectral lines of MgIII. Data are presented for an electron density of 1017 cm?3 and temperatures T = 0.5?10.0 (104 K). The matrix elements used in these calculations have been determined from 23 configurations of MgIII: 2s22p6, 2s22p53p, 2s22p54p, 2s22p54f and 2s22p55f for even parity and 2s22p5ns (n = 3?6), 2s22p5nd (n = 3?9), 2s22p55g and 2s2p6np (n = 3?8) for odd parity. For the intermediate coupling (IC) calculations, we use the standard method of least-squares fitting from experimental energy levels by means of the Cowan computer code. Also, in order to test the matrix elements used in our calculations, we present calculated values of 70 transition probabilities of MgIII spectral lines and 14 calculated values of radiative lifetimes of MgIII levels. There is good agreement between our calculations and experimental radiative lifetimes. Spectral lines of MgIII are relevant in astrophysics and also play an important role in the spectral analysis of laboratory plasma. Theoretical trends of the Stark broadening parameter versus the temperature for relevant lines are presented. No values of Stark parameters can be found in the bibliography.

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Las células solares de banda intermedia se inventaron en España. Constituyen una propuesta para aumentar la eficiencia de las células solares por encima del límite de Shockley y Queisser para células de un solo gap. El número de ideas para llevarlas a la práctica (desde la utilización de puntos cuánticos a la implantación selectiva de impurezas) se ha ido expandiendo a medida que nuestra comprensión ha ido aumentando. En este artículo repasamos el concepto de célula solar de banda intermedia y algunas de estas ideas para llevarla a la práctica.

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Análisis del riesgo volcánico. We show the preliminary results of the study of 561 volcanic bombs ejected from a pyroclastic cone during the 1730-1736 Timanfaya eruption (Lanzarote, Canary Islands). This cone displays the highest concentration of big bombs (major axis higher than 1 m) of Timanfaya. More than 560 bombs have been studied to calculate their reach. The results suggest that bombs of 1t have a reach of 409 m, while bombs up to 28 t have a reach of 248 m. These data may be used to define a security area once a vent has been opened, but also to calculate other data such the initial velocity of ejection. The geomorphological analysis and the study of the deposits also contribute to better understand an undocumented episode of the Timanfaya eruption and also provide important data for volcanic bombs modeling for volcanic hazard analysis.