Recursos de colección

Archivo Digital UPM (115.892 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Tipo de documento = Artículo

Mostrando recursos 1 - 15 de 15

  1. Material selection for spallation neutron source windows. Application to PDS-XADS and XT-ADS prototypes

    Sordo Balbín, Fernando; Abánades Velasco, Alberto; Lafuente Mazuecos, Antonio; Martínez-Val Peñalosa, José María; Perlado Martín, José Manuel
    High performance neutron sources are being proposed for many scientific and industrial applications, ranging from material studies, hybrid reactors and transmutation of nuclear wastes. In the case of transmutation of nuclear wastes, accelerator driven systems (ADS) are considered as one of the main technical options for such purpose. In ADS a high performance spallation neutron source becomes an essential element for its operation and control. This spallation source must fulfil very challenging nuclear and thermo-mechanical requirements, because of the high neutron rates needed in ADS. The material selection for this key component becomes of paramount importance, particularly the source window...

  2. Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors

    Montes Pita, María José; Abánades Velasco, Alberto; Martínez-Val Peñalosa, José María; Valdés del Fresno, Manuel
    Usual size of parabolic trough solar thermal plants being built at present is approximately 50 M We. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice. A too large field will be partially useless under high solar irradiance values whereas a small field will mainly make the power block to work at part-load conditions. This paper presents an economic optimization of the solar multiple for a...

  3. Sede de la Caja de Arquitectos, Bilbao

    Urzáiz González, Pedro; Pérez-Plá de Viu, Carlos
    Artículo sobre la obra en Bilbao de la Sede de la Caja de Arquitectos de Eduardo Arroyo

  4. Alta tecnología aplicada a las máquinas trasplantadoras

    Barreiro Elorza, Pilar; Diezma Iglesias, Belen; Valero Ubierna, Constantino
    La tecnica del trasplante, aunque mas costosa que la siembra, se ha extendido en gran manera debido al elevado coste de las semillas hibridas y a la aparicion de la micropropagacion para determinadas especies. En este articulo se realiza una clasificacion de las distintas trasplantadoras manuales y automaticas y se dan a conocer los ultimos controles electronicos que incorporan y que son de gran utilidad para el operario.

  5. Models for predicting friction coefficient and parameters with influence in elastohydrodynamic lubrication

    Lafont Morgado, Pilar; Echávarri Otero, Javier; Muñoz Sanz, José Luis; Diaz Lantada, Andres; Muñoz Guijosa, Juan Manuel; Lorenzo Yustos, Héctor; Leal Wiña, María del Pilar; Muñoz García, Julio
    This article shows different friction prediction models applicable to lubricants in point contacts under an elastohydrodynamic regime. The types of models used are two variations of the Newtonian theory, the Limiting Shear Stress model and the one based on Carreau's equation. The article sets out the theoretical calculation procedures and the ensuing equations for calculating the friction coefficient. The aims of the article are to study the effect of the parameters with influence on friction and to compare the model's results with those given by an experimental stage performed on a mini traction machine. This test system allows the measurement...

  6. He production and induced swelling in KOYO-F

    Gámez Mejías, María de Linarejos; Gamez Mejias, Berta; Caturla Terol, Maria Jose; Ortiz, Christopher; Perlado Martín, José Manuel
    From preliminary results[1] of neutron fluxes and energy spectra obtained for the vacuum vessel of the Fast Ignition Fusion Reactor KOYO-F, the distribution of Primary Knock-on Atoms (PKA), necessary to quantify defect production, has been calculated. In the presence of He these defects could induce swelling through nucleation of voids and bubbles. Kinetic Monte Carlo models are being developed to predict the evolution of these defects in different metals. As a first study we have focused on He in Ni, since there are systematic experimental results available.

  7. Assessment of vehicle emissions projections in Madrid (Spain) from 2004 to 2012 considering several control strategies

    Lumbreras Martin, Julio; Valdes, M.; Borge García, Rafael; Rodríguez Hurtado, María Encarnación
    Road transport is a major source of air pollutant emissions in European cities. Moreover, vehicle exhaust emissions have been the cause of much concern about the effects of urban air pollution on human health. Local authorities need to develop strategies to control vehicular emissions through technological and socioeconomical measures. For this reason, an efficiency assessment of possible future measures to reduce air pollution is required for future traffic planning, regulatory and fiscal initiatives. This paper presents the assessment of several mobility and technology scenarios that can be used for emission reductions in Madrid (Spain) in the period 2004–2012. Pollutants considered...

  8. A comprehensive sensitivity analisys of the WRF model for air quality applications over the Iberian Peninsula

    Borge García, Rafael; Alexandrov, Vassil N.; Vas, Juan José del; Rodríguez Hurtado, María Encarnación; Lumbreras Martin, Julio
    Meteorological inputs play a vital role on regional air quality modelling. An extensive sensitivity analysis of the Weather Research and Forecasting (WRF) model was performed, in the framework of the Integrated Assessment Modelling System for the Iberian Peninsula (SIMCA) project. Up to 23 alternative model configurations, including Planetary Boundary Layer schemes, Microphysics, Land-surface models, Radiation schemes, Sea Surface Temperature and Four-Dimensional Data Assimilation were tested in a 3 km spatial resolution domain. Model results for the most significant meteorological variables, were assessed through a series of common statistics. The physics options identified to produce better results (Yonsei University Planetary Boundary...

  9. A model to calculate consistent atmospheric emission projections and its application to Spain

    Lumbreras Martin, Julio; Borge García, Rafael; Andrés Almeida, Juan Manuel de; Rodríguez Hurtado, María Encarnación
    Global warming and air quality are headline environmental issues of our time and policy must preempt negative international effects with forward-looking strategies. As part of the revision of the European National Emission Ceilings Directive, atmospheric emission projections for European Union countries are being calculated. These projections are useful to drive European air quality analyses and to support wide-scale decision-making. However, when evaluating specific policies and measures at sectoral level, a more detailed approach is needed. This paper presents an original methodology to evaluate emission projections. Emission projections are calculated for each emitting activity that has emissions under three scenarios: without...

  10. A dislocation dynamics study of the strength of stacking fault tetrahedra. Part II: interactions with mixed and edge dislocations

    Martínez Sáez, Enrique; Marian, Jaime; Perlado Martín, José Manuel
    In this paper we present the sequel to Part I and present a comprehensive dislocation dynamics study of the strength of stacking fault tetrahedra to mixed and edge dislocation glides in fcc Cu.

  11. A dislocation dynamics study of the strength of stacking fault tetrahedra. Part I: interactions with screw dislocations

    Martínez Sáez, Enrique; Marian, Jaime; Arsenlis, A.; Victoria, Maximo Pedro; Perlado Martín, José Manuel
    We present a comprehensive dislocation dynamics (DD) study of the strength of stacking fault tetrahedra (SFT) to screw dislocation glide in fcc Cu. Our methodology explicitly accounts for partial dislocation reactions in fcc crystals, which allows us to provide more detailed insights into the dislocation– SFT processes than previous DD studies. The resistance due to stacking fault surfaces to dislocation cutting has been computed using atomistic simulations and added in the form of a point stress to our DD methodology. We obtain a value of 1658.9 MPa, which translates into an extra force resolved on the glide plane that dislocations...

  12. Synchronous parallel kinetic Monte Carlo for continuum diffusion-reaction systems

    Martínez Sáez, Enrique; Marian, Jaime; Kalos, Malvin; Perlado Martín, José Manuel
    A novel parallel kinetic Monte Carlo (kMC) algorithm formulated on the basis of perfect time synchronicity is presented. The algorithm is intended as a generalization of the standard n-fold kMC method, and is trivially implemented in parallel architectures. In its present form, the algorithm is not rigorous in the sense that boundary conflicts are ignored. We demonstrate, however, that, in their absence, or if they were correctly accounted for, our algorithm solves the same master equation as the serial method. We test the validity and parallel performance of the method by solving several pure diffusion problems (i.e. with no particle...

  13. Atomistically informed dislocation dynamics in fcc crystals

    Martínez Sáez, Enrique; Marian, Jaime; Arsenlis, A.; Victoria, Maximo Pedro; Perlado Martín, José Manuel
    We develop a nodal dislocation dynamics (DD) model to simulate plastic processes in fcc crystals. The model explicitly accounts for all slip systems and Burgers vectors observed in fcc systems, including stacking faults and partial dislocations. We derive simple conservation rules that describe all partial dislocation interactions rigorously and allow us to model and quantify cross-slip processes, the structure and strength of dislocation junctions, and the formation of fcc-specific structures such as stacking fault tetrahedra. The DD framework is built upon isotropic non-singular linear elasticity and supports itself on information transmitted from the atomistic scale. In this fashion, connection between...

  14. First approaches to the usability of Digital Map Libraries

    Fernández Wyttenbach, Alberto; Moya Honduvilla, Javier; Bernabe Poveda, Miguel Angel; Álvarez, Mabel
    The Internet is a powerful tool providing different online communication options on geographic approaches. In addition to searching, geoportals provide tools to visualize, explore and download information. Cartographic heritage contained in the Digital Map Libraries (DML) stands out as an exceptional case within the generic frame of a Spatial Data Infrastructure (SDI). There are useful and basic similarities between the global reality of an SDI as a distributed geoportal and a DML; conformance to standards, agreements and services. However, some technological and policy considerations must be taken into account apart from the characteristics common to all SDI in any thematic...

  15. Verificación en campo de las prestaciones técnicas de la serie 6000 de New Holland

    Barreiro Elorza, Pilar; Valero Ubierna, Constantino
    En este artículo se comparan dos tractores de la serie 6000 de New Holland: 6030 Delta y 6070 Grande en relación a las especificaciones de todas los modelos de la gama (Delta, Elite y Grande), con especial énfasis en los controles electrónicos y su programación.

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