Recursos de colección

Archivo Digital UPM (114.084 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 - 20 de 29

  1. New Virtual Environment for Active Learning on Parameter Adjustment of Plastic Injection Molding

    Marquez Sevillano, Juan de Juanes; Rodríguez Villagrá, María; Martínez Muneta, María Luisa; Pérez García, Jesus Maria
    This paper describes some aspects of new software development and its academic application. This program is an alternative to enhance and to improve the available resources for students to acquire practical knowledge in plastic injection molding parameterization. A virtual injection molding environment has been developed, which allows preliminary machine capacity determination, number of cavities analysis, injection cycle parameter definition, and defects analysis and representation. The environment allows the student to carry out an iteration process in order to optimize the injection molding process parameters. All decision making is based on an Expert System which response is similar to a skilled...

  2. 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 Martin, Jose 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...

  3. 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...

  4. Alpha decay perturbations by atomic effects at extreme conditions

    Eliezer, S.; Martínez-Val Peñalosa, José María; Piera, Mireia
    The alpha tunneling effect in the presence of electron screening is calculated within the Debye model. Calculations show that very small effects are predicted by cooling the metal to low temperatures. However the alpha lifetime decay may be reduced by about 15% if solid samples of the alpha emitters are cooled and compressed to relatively high densities. These conditions can be achieved at high pressures by using existing diamond anvil cells (DACs). Even so, practical consequences for speeding-up the decay of actinides (from the nuclear waste) seem to be negligible. Keywords: Alpha decay; Lifetime reduction; Extreme atomic conditions

  5. Performance of a direct steam generation solar thermal power plant for electricity production as a function of the solar multiple

    Montes Pita, María José; Abánades Velasco, Alberto; Martínez-Val Peñalosa, José María
    This paper describes the influence of the solar multiple on the annual performance of parabolic trough solar thermal power plants with direct steam generation (DSG). The reference system selected is a 50 M We DSG power plant, with thermal storage and auxiliary natural gas-fired boiler. It is considered that both systems are necessary for an optimum coupling to the electricity grid. Although thermal storage is an opening issue for DSG technology, it gives an additional degree of freedom for plant performance optimization. Fossil hybridization is also a key element if a reliable electricity production must be guaranteed for a defined...

  6. 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; Valdes 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...

  7. 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...

  8. Experimentación en condiciones de gravedad reducida

    Perales Perales, José Manuel; Meseguer Ruiz, José; Pindado Carrion, Santiago; Meseguer, Encarnación
    Como es bien sabido, la ley de gravitación de Newton establece que entre dos cuerpos de masas M y m, cuyos centros de masas están separados entre sí una distancia r, aparece una fuerza de atracción que es proporcional al producto de las masas e inversamente proporcional al cuadrado de la distancia: F = GMmr−2, es la constante de proporcionalidad, G, es la denominada constante de gravitación universal, que vale G ≈6,6710−11 m3•s−2•kg−1. Esta fuerza es la atracción gravitatoria, y la generalización del enunciado a n cuerpos es obvia. En las proximidades de la Tierra el efecto dominante en la...

  9. Optimización de Procesos de Inducción de Tensiones Residuales en Compresión en Materiales Metálicos por Ondas de Choque Generadas por Láser

    Morales Furió, Miguel; Porro González, Juan Antonio; Molpeceres Álvarez, Carlos Luis; García Beltrán, Ángel; Acebal, Nestor; Ocaña Moreno, José Luis
    El tratamiento superficial mediante ondas de choque generadas por láser (LSP) se basa en la aplicación de un pulso láser de alta intensidad (I > 1 GW/cm2; / < 50 ns) en la superficie de un blanco metálico provocando la vaporización súbita de su superficie y su conversión en un plasma de alta temperatura y densidad que induce la propagación de una onda de choque en el blanco. El resultado característico del tratamiento consiste en la inducción de un campo de tensiones residuales de compresión en profundidad y que mejoran el comportamiento de la pieza tratada. En este artículo, se...

  10. Microconformado de Materiales Metálicos mediante Pulsos Láser en el Dominio de ns

    Garcia Garcia, Oscar; Morales Furió, Miguel; García-Ballesteros Ramírez, Juan José; Porro González, Juan Antonio; Molpeceres Álvarez, Carlos Luis; Sanchez Perez, Angel M.; Ocaña Moreno, José Luis
    La demanda de miniaturización introducida, entre otros, por la industria de fabricación de MEMS (Micro Electro Mechanical Systems), hace necesario caracterizar y validar los procesos que emplean el láser en el microconformado de materiales metálicos a escala submilimétrica. Como alternativa al microconformado térmico, que hace uso de las deformaciones de origen térmico inducidas por la radiación láser, el microconformado mediante pulsos láser en el dominio de ns hace posible el conformado de materiales metálicos manteniendo, o incluso mejorando, las propiedades mecánicas de los mismos debido a la inducción de tensiones residuales de compresión en la superficie de la pieza tratada....

  11. Avances en la fabricación de células y módulos fotovoltaicos de silicio en capa fina mediante láser

    Fernández Robledo, Susana; Lauzurica Santiago, Sara; García-Ballesteros Ramírez, Juan José; Molpeceres Álvarez, Carlos Luis; Guadaño Ayuso, Gonzalo; Allen-Perkins, F.; Ocaña Moreno, José Luis
    El láser es un instrumento omnipresente en la fabricación de módulos fotovoltaicos. Los láser estándar para la interconexión monolítica de dispositivos de lámina delgada de a-Si son láser de estado sólido bombeados por diodo (DPSS) emitiendo en longitudes IR (λ=1064 nm) y en VIS (λ=532 nm). En este trabajo mostramos estudios de ablación de algunos materiales fotovoltaicos (óxidos conductores transparentes (OCT) y a-Si) con láser emitiendo en UV en el régimen de nanosegundos (ns). La afección térmica resultante en la ablación es menor, y por tanto se reduciría el riesgo de cortocircuitos en la interconexión monolítica, convirtiendo a las fuentes...

  12. Calibración de Microscopios Confocales

    Vicente y Oliva, Jesus de; Molpeceres Álvarez, Carlos Luis; Guarneiros, O.; García-Ballesteros Ramírez, Juan José
    El microscopio confocal ha sido durante mucho tiempo un instrumento de observación tridimensional con múltiples aplicaciones especialmente dentro de la biología. Sin embargo en los últimos años ha comenzado a ser utilizado como instrumento de medida en diferentes áreas de la ingeniería. En la actualidad existen muchas especificaciones de productos (dimensionales, angulares, acabado superficial) en las escalas micrométricas y nanométricas que pueden o podrían ser verificadas utilizando este instrumento. Pero para que esta verificación sea válida dentro de un sistema de calidad el microscopio confocal debe ser trazable. Esta ponencia presenta una solución sencilla a este problema implementada en el...

  13. Micromecanizado Láser de Componentes de Gran calidad de Acabado Superficial

    Molpeceres Álvarez, Carlos Luis; García-Ballesteros Ramírez, Juan José; Lauzurica Santiago, Sara; Vicente y Oliva, Jesus de; Ocaña Moreno, José Luis
    El uso de láseres pulsados con anchos temporales de nanosegundos y longitudes de onda en el rango Ultravioleta, permiten un preciso control del material abferido, convirtiendo dicha técnica en una herramienta fundamental para mecanizados que requieren de una gran calidad y acabado, con relaciones de aspecto muy altas. Este trabajo presenta un análisis paramétrico de la influencia de las distintas variables de proceso para diferentes tipos de materiales (metálicos, dieléctricos, materiales orgánicos, etc) en la calidad y acabado final. The use of nanoseconds U.V. lasers permits a precise control in ablation’s processes. As a result this tool plays a fundamental...

  14. Dynamic response of an accelerator driven system to accelerator beam interruptions for criticality

    Lafuente Mazuecos, Antonio; Abánades Velasco, Alberto; Sordo Balbín, Fernando; León López, Pablo Teófilo; Martínez-Val Peñalosa, José María
    Subcritical nuclear reactors driven by intense neutron sources can be very suitable tools for nuclear waste transmutation, particularly in the case of minor actinides with very low fractions of delayed neutrons. A proper control of these systems needs to know at every time the absolute value of the reactor subcriticality (negative reactivity), which must be measured by fully reliable methods, usually conveying a short interruption of the accelerator beam in order to assess the neutron flux reduction. Those interruptions should be very short in time, for not disturbing too much the thermal magnitudes of the reactor. Otherwise, the cladding and...

  15. Diseño de un Sistema de Monitorización y Control de Procesos de Tratamiento Térmico Superficial de Materiales con Láser Mediante Realimentación de Estados

    Pérez Rodríguez, José Antonio; Ocaña Moreno, José Luis; Molpeceres Álvarez, Carlos Luis; Morales Furió, Miguel; Blasco Litago, Manuel; García Beltrán, Ángel
    En el presente artículo se propone el empleo de un innovador Controlador Lineal Mínimo Cuadrático para Procesos de Tratamiento Térmico Superficial de Materiales con Láser, el cual mediante realimentación del vector de estados permite incrementar considerablemente la calidad y uniformidad de los tratamientos realizados, reduciendo de forma significativa la tasa de rechazos y mejorando significativamente la productividad y eficiencia del proceso. De un modo complementario, además de analizar las prestaciones del sistema de control propuesto en base a los criterios típicos de validación, tales como la sobreoscilación y el tiempo de asentamiento, se analizan también otros parámetros de interés, tales...

  16. Virtual reality applied to a full simulator of electrical sub-stations

    Romero Rey, Gregorio; Maroto Ibáñez, Joaquín; Félez Mindán, Jesús; Cabanellas Becerra, Jose Maria; Martínez Muneta, María Luisa; Carretero Díaz, Antonio María
    This paper presents an application designed to train electrical sub-station operators by means of a virtual reality environment. The application allows full viewing of any of the sub-stations in the power supply network. With the appropriate hardware (HMD, 3D mouse and tracking systems) it is possible to navigate into the virtual world and interact with the elements. Each of the sub-station components has been reproduced in the simulation model, including the behavior laws associated with it, so the complete functionality of the sub-station can be simulated. This module is built into a larger and more complex computer system composed of...

  17. TEMPLUM: A Process Adapted Numerical Simulation Code for The 3D Predictive Assessment of Laser Surface Heat Treatments in Planar Geometry

    García Beltrán, Ángel; Ocaña Moreno, José Luis; Molpeceres Álvarez, Carlos Luis
    A process adapted numerical simulation code for the 3D predictive assessment of laser heat treatment of materials has been developed. Primarily intended for the analysis of the laser transformation hardening of steels, the code has been successfully applied for the predictive characterization of other metallic and non metallic materials posing specific difficulties from the numerical point of view according to their extreme thermal and absorption properties. Initially based on a conventional FEM calculational structure, the developed code (TEMPLUM) reveals itself as an extremely useful prediction tool with specific process adapted features (not usually available in FEM heat transfer codes) in...

  18. 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...

  19. 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.

  20. 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...

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