Recursos de colección

Archivo Digital UPM (115.086 recursos)

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

Materia = Materiales

Mostrando recursos 1 - 20 de 29

  1. Mechanical behavior of bilayered small-diameter nanofibrous structures as biomimetic vascular grafts

    Montini Ballarin, Florencia; Calvo Aguilar, Daniel; Caracciolo, Pablo C.; Rojo Pérez, Francisco Javier; Frontini, Patricia M.; Abraham, Gustavo A.; Guinea Tortuero, Gustavo V.
    To these days, the production of a small diameter vascular graft (<6 mm) with an appropriate and permanent response is still challenging. The mismatch in the grafts mechanical properties is one of the principal causes of failure, therefore their complete mechanical characterization is fundamental. In this work the mechanical response of electrospun bilayered small-diameter vascular grafts made of two different bioresorbable synthetic polymers, segmented poly (ester urethane) and poly (L-lactic acid), that mimic the biomechanical characteristics of elastin and collagen is investigated. AJ-shaped response when subjected to internal pressure was observed as a cause of the nanofibrous layered structure, and...

  2. Tratado de Minería de Recursos Hídricos en Islas Volcánicas Oceánicas

    Santamarta Cerezal, Juan Carlos
    La presente obra aporta un compendio de conceptos, metodologías y técnicas necesarias para poder acometer un proyecto minero para la explotación de las aguas subterráneas en las islas volcánicas oceánicas. El texto presenta dos partes diferenciadas. Por un lado, se introduce en la ciencia y el conocimiento básico necesario para entender el funcionamiento de los acuíferos en las islas volcánicas, es decir, la hidrología e hidrogeología de las islas oceánicas. Continúa con la técnica y estrategias de extracción del agua subterránea y, se complementa, con un anexo donde se indican las partes fundamentales que deben comprender un proyecto minero de...

  3. Influencia de los tratamientos térmicos en la resistencia a la corrosión en medios salinos de uniones soldadas de aleación de magnesio AZ31B

    Palomo Colao, David
    Las especiales características del magnesio, en especial su baja densidad y fácil accesibilidad en el mercado debido a su abundancia y bajo precio, lo convierten en uno de los metales más interesantes dentro del campo de la ingeniería dadas las posibilidades que ofrece, y al mismo tiempo reducir el gasto energético gracias a la capacidad de fabricar estructuras más ligeras y compactas. Gracias a estas características su utilización se ha extendido a ámbitos tan importantes como el aeroespacial, militar, deportivo, automovilista, etc. A pesar de las ventajas que presenta el magnesio y sus aleaciones, su utilización presenta una serie de...

  4. Deformation, strengthening and fracture mechanisms of nanoscale Al/SiC multilayers

    Yang, Lingwei
    Los nanolaminados de Al/SiC son materiales multicapa metal-cerámico con propiedades mecánicas singulares. Por ejemplo, se han reportando resistencias a temperatura ambiente extremadamente altas cuando el espesor de las capas individuales se reduce por debajo de 100 nm. Este comportamiento se ha atribuido a la elevada densidad de intercaras y al espesor nanométrico de las capas. Sin embargo, existen varios interrogantes fundamentales acerca de los mecanismos de deformación y fractura. Primero, no está claro cómo se pueden deformar las capas metálicas cuando su espesor se reduce a dimensiones nanométricas ni el papel que juegan las capas cerámicas en su deformación. Segundo, aunque su comportamiento es potencialmente muy anisótropo, estos materiales...

  5. Dynamic fracture of high-strength metallic alloys: experiments and modelling

    Pérez Martín, María Jesús
    Fracture toughness is a property which describes the ability of a material containing a crack to resist fracture. Such a characteristic is one of the most important properties for describing the failure criteria of materials and may be a function of loading rate and temperature. Therefore, in the case of materials that may be subjected to dynamic loads or extreme conditions, it is crucial to be aware of the evolution of their fracture behaviour with such variables. The main objective of this PhD thesis was to design and develop a novel experimental technique that allowed measuring the dynamic fracture-initiation toughness...

  6. Dynamic fracture of high-strength metallic alloys: experiments and modelling

    Pérez Martín, María Jesús
    Fracture toughness is a property which describes the ability of a material containing a crack to resist fracture. Such a characteristic is one of the most important properties for describing the failure criteria of materials and may be a function of loading rate and temperature. Therefore, in the case of materials that may be subjected to dynamic loads or extreme conditions, it is crucial to be aware of the evolution of their fracture behaviour with such variables. The main objective of this PhD thesis was to design and develop a novel experimental technique that allowed measuring the dynamic fracture-initiation toughness...

  7. Dynamic fracture of high-strength metallic alloys: experiments and modelling

    Pérez Martín, María Jesús
    Fracture toughness is a property which describes the ability of a material containing a crack to resist fracture. Such a characteristic is one of the most important properties for describing the failure criteria of materials and may be a function of loading rate and temperature. Therefore, in the case of materials that may be subjected to dynamic loads or extreme conditions, it is crucial to be aware of the evolution of their fracture behaviour with such variables. The main objective of this PhD thesis was to design and develop a novel experimental technique that allowed measuring the dynamic fracture-initiation toughness...

  8. Caracterización de propiedades reológicas de fluidos para aplicaciones en Lift mediante técnicas de visión artificial

    Sbant, Magda
    En este trabajo se ha hecho, en primer lugar, un estudio de las propiedades reológicas de algunos fluidos para después caracterizar un proceso de impresión mediante láser. Parte de este estudio ha sido medir la tensión superficial de algunos fluidos. Existe una gran variedad de métodos para medir la tensión superficial de un fluido, pero la más simple (en términos de instrumentación, más robusta y más versátil es una técnica llamada pendant drop tensiometry o gota que cuelga de una aguja. Este método es el que se ha usado en este trabajo. La técnica de la gota que cuelga de una aguja...

  9. Nuevo procedimiento de ensayo para determinar el coeficiente de pulimento acelerado de mezclas bituminosas

    Ramírez Rodríguez, Antonio
    La resistencia al deslizamiento es una de las propiedades que tienen más influencia en lo que respecta a la seguridad ofrecida por el pavimento y tiene una gran repercusión en la reducción de los accidentes, especialmente en circunstancias de lluvia o superficie mojada. La resistencia al deslizamiento en los pavimentos tiende a decrecer con el paso del tiempo, debido a la acción del tráfico y a otros factores, lo que repercute en una mayor inseguridad para los conductores. La medida de la resistencia al deslizamiento se ha convertido en una herramienta básica para la gestión de las redes de carreteras....

  10. Standard and strain gradient crystal plasticity models: application to Titanium

    Rodríguez Galán, Daniel
    The necessity of improvements in metallic materials requires to understand the mechanisms that give the evolution of its mechanical properties at the micrometer scale. These mechanisms whose dependence and effects span several scales over length and time derive from plasticity in metals. In this realm, the current work is focused on the simulation at the continuum scale of the mechanical behavior of metals with a micromechanical description based on crystal plasticity because of its proven suitability to characterize the microstructural behaviour in crystalline materials. However, local crystal plasticity models are not able to capture the size effects. For this reason, strain gradient plasticity theories are introduced. This...

  11. Influencia de las condiciones de ejecución en la resistencia de anclajes de fibra de carbono para refuerzos en estructuras de hormigón

    Villanueva Llauradó, Paula
    Los materiales compuestos con fibra en matriz polimérica (FRP) son muy utilizados actualmente para actuaciones de refuerzo y rehabilitación de estructuras de hormigón armado y de fábrica, tanto de obra civil como de edificación. Entre las ventajas de estos materiales destacan su alta resistencia a tracción, alta relación resistencia/peso y buenas propiedades durables. En estructuras de hormigón se pueden emplear para refuerzo de elementos a compresión por confinamiento, y de elementos a flexión y cortante tales como vigas y losas. Las técnicas de refuerzo con FRP se clasifican atendiendo a la disposición del refuerzo, que puede ser exterior adherida a la superficie del elemento a reforzar o bien parcialmente embebida...

  12. Neutronic design for ESS-Bilbao neutron source

    Sordo Balbín, Fernando; Terrón, Santiago; Magán, Miguel; Muhrer, Guenter; Ghiglino Novoa, Angelo; Martínez, F.; Vicente Albendea, Juan Francisco de; Vivanco Sánchez, Raúl; Perlado Martín, José Manuel; Bermejo, F. J.
    The European Spallation Source-Bilbao (ESS-Bilbao) project plans to build an accelerator facility compliant with the ESS-AB requirements which will be able to drive several experimental stations for research purposes involving intense proton beams with currents up to 75 mA, 50 MeV of final energy, 1.5 ms of pulse length and up to 50 Hz repetition rate. The accelerator will also drive a compact neutron source which will provide useful neutron beams to carry out experiments on moderator optimization, neutron optics devices and general neutron instrumentation as well as preparation work for experiments to be carried out by neutron beam users...

  13. Conceptual design of the beryllium rotating target for the ESS-Bilbao facility

    Terrón, Santiago; Sordo Balbín, Fernando; Magán, Miguel; Ghiglino Novoa, Angelo; Martínez, F.; Vicente Albendea, Juan Francisco de; Vivanco Sánchez, Raúl; Thomsen, Knud; Perlado Martín, José Manuel; Bermejo, F. J.; Abánades Velasco, Alberto
    The ESS-Bilbao facility, hosted by the University of the Basque Country (UPV/EHU), envisages the operation of a high-current proton accelerator delivering beams with energies up to 50 MeV. The time-averaged proton current will be 2.25 mA, delivered by 1.5 ms proton pulses with a repetition rate of 20 Hz. This beam will feed a neutron source based upon the Be (p,n) reaction, which will enable the provision of relevant neutron experimentation capabilities. The neutron source baseline concept consists in a rotating beryllium target cooled by water. The target structure will comprise a rotatable disk made of 6061-T6 aluminium alloy holding...

  14. Neutronic analysis of the bi-spectral moderator such as that proposed for ESS

    Magán, Miguel; Sordo Balbín, Fernando; Zanini, Luca; Terrón, Santiago; Ghiglino Novoa, Angelo; Martínez, F.; Vicente Albendea, Juan Francisco de; Vivanco Sánchez, Raúl; Perlado Martín, José Manuel; Bermejo, F. J.; Mezei, Ferenc; Muhrer, Guenter
    This paper reports on design studies concerning a moderator concept which aims to maximize the time averaged flux. The idea is to provide neutron spectra showing two clear maxima, with peaks at View the MathML source and View the MathML source arising from leakage from both cryogenic and thermal moderators. Such a concept known as a bi-spectral moderator (Mezei, 2006 [1]) while proven on a reactor source has only been examined for the ESS 2003 proposal. Filges et al. (2003 [2]), which featured a different design than the current ESS. This paper thus reports on a baseline design for such...

  15. Aporte martensíticos en la soldadura de aceros 9%Cr

    Oñoro Lopez, Javier; Portolés García, Antonio; Ibars Almonacil, Jose Ramón
    Los aceros 9% en cromo son utilizados en plantas de producción de energía eléctrica debido a su elevada resistencia a la corrosión, buenas propiedades mecánicas y resistencia a la termofluencia. Estos aceros presentan una estructura completamente martensítica. Sin embargo, la realización de uniones soldadas los hace susceptibles a la aparición en la zona fundida de ferrita delta, que reduce sus propiedades de termofluencia y tenacidad. Este trabajo analiza la microestructura del metal de aporte producido durante la soldadura manual con electrodo consumible (SMAW) utilizando aportes con diferentes composiciones en cromo y otros elementos de aleación como molibdeno, wolframio, cobre y...

  16. Techniques to accelerate convergence of stress-controlled molecular dynamics simulations of dislocation motion

    Cereceda, D.; Perlado Martín, José Manuel; Marian, Jaime
    Dislocation mobility —the relation between applied stress and dislocation velocity—is an important property to model the mechanical behavior of structural materials. These mobilities reflect the interaction between the dislocation core and the host lattice and, thus, atomistic resolution is required to capture its details. Because the mobility function is multiparametric, its computation is often highly demanding in terms of computational requirements. Optimizing how tractions are applied can be greatly advantageous in accelerating convergence and reducing the overall computational cost of the simulations. In this paper we perform molecular dynamics simulations of ½ 〈1 1 1〉 screw dislocation motion in tungsten...

  17. Conceptual design of the liquid metal laboratory of the TECHNOFUSION facility

    Abánades Velasco, Alberto; García, A.; Casal, N.; Perlado Martín, José Manuel; Ibarra, A.
    The application of liquid metal technology in fusion devices requires R&D related to many phenomena: interaction between liquid metals and structural material as corrosion, erosion and passivation techniques; magneto-hydrodynamics; free surface fluid-dynamics and any other physical aspect that will be needed for their safe reliable operation. In particular, there is a significant shortage of experimental facilities dedicated to the development of the lithium technology. In the framework of the TECHNOFUSION project, an experimental laboratory devoted to the lithium technology development is proposed, in order to shed some light in the path to IFMIF and the design of chamber's first wall...

  18. Application of Ultraintense Lasers to validate materials for laser fusion: production of ions and other relevant species

    Alvarez Ruiz, Jesus; Mima, K.; Tanaka, K.; Perlado Martín, José Manuel
    Justification of the need and demand of experimental facilities to test and validate materials for first wall in laser fusion reactors - Characteristics of the laser fusion products - Current ?possible? facilities for tests Ultraintense Lasers as ?complete? solution facility - Generation of ion pulses - Generation of X-ray pulses - Generation of other relevant particles (electrons, neutrons..)

  19. Materials Research for HiPER Laser Fusion Facilities: Chamber Wall, Structural Material and Final Optics

    Alvarez Ruiz, Jesus; Rivera de Mena, Antonio; Gonzalez Arrabal, Raquel; Garoz Gómez, David; Rio Redondo, Emma del; Perlado Martín, José Manuel
    The European HiPER project aims to demonstrate commercial viability of inertial fusion energy within the following two decades. This goal requires an extensive Research &Development program on materials for different applications (e.g., first wall, structural components and final optics). In this paper we will discuss our activities in the framework of HiPER to develop materials studies for the different areas of interest. The chamber first wall will have to withstand explosions of at least 100 MJ at a repetition rate of 5-10 Hz. If direct drive targets are used, a dry wall chamber operated in vacuum is preferable. In this...

  20. IFMIF suitability for evaluation of fusion functional materials

    Casal, N.; Sordo Balbín, Fernando; Mota, F.; Jordanova, J.; Garcia, A.; Ibarra, A.; Vila, R.; Rapisarda, D.; Queral, V.; Perlado Martín, José Manuel
    The International FusionMaterials Irradiation Facility (IFMIF) is a future neutron source based on the D-Li stripping reaction, planned to test candidate fusionmaterials at relevant fusion irradiation conditions. During the design of IFMIF special attention was paid to the structural materials for the blanket and first wall, because they will be exposed to the most severe irradiation conditions in a fusion reactor. Also the irradiation of candidate materials for solid breeder blankets is planned in the IFMIF reference design. This paper focuses on the assessment of the suitability of IFMIF irradiation conditions for testing functionalmaterials to be used in liquid blankets and...

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