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The present paper describes the experiences gained from the design methodology and operation of a 3D physical model experiment aimed to investigate the dynamic behaviour of a spar buoy (SB) off-shore floating wind turbine (WT) under different wind and wave conditions. The physical model tests have been performed at Danish Hydraulic Institute (DHI) off-shore wave basin within the European Union-Hydralab+ Initiative, in April 2019. The floating WT model has been subjected to a combination of regular and irregular wave attacks and wind loads.

Floating wind turbines (FWTs) are proposed as a method to harness the significant wind energy resource in deep water. International research efforts have led to the development of coupled numerical global analysis tools for FWTs in order to understand their behavior under wind and wave actions. The hydrodynamic models in such tools are typically based on first-(and second-)order potential flow theory, sometimes also including Morison s equation. In order to accurately model highly nonlinear waves, their interaction with a floating platform, and obtain estimates of the resulting loads on the structure, a numerical wave tank approach is generally needed. In this thesis, the response of floating structures to nonlinear wave loading is investigated by means of two different numerical approaches: a fully nonlinear Navier-Stokes/VOF solver and a second-order potential flow theory solver. Firstly, the fully nonlinear Navier-Stokes/VOF numerical wave tank, developed within the open-source CFD toolbox OpenFOAMframework (version 1606+), is validated against experimental data for two cases. These comprise the response of a 2D floating box and a 3D floating vertical cylinder. In order to model the motions of the floating structures, together with the generation and absorption of the waves, the interDyMFoam solver, provided by the OpenFOAMlibrary, is extended with the waves2Foam package, developed by Jacobsen at al. (2012). Furthermore, a simple catenary mooring line is implemented for the moored cases. Secondly, a potential flow theory based model of the OC5-semisubmersible floating platform is generated. The frequency-domain analysis is done with the Wadam software and the time-domain simulations with SIMO. This model is validated against measurement data from a 1:50 scale test campaign performed at the MARIN offshore wave basin and the fully nonlinear validated CFD model. Lastly, both numerical models of the OC5-semisubmersible are compared in order to assess the suitability of the diffraction model in two different conditions where nonlinearities are of relevance. The first one involves very long waves, with periods close to 20s, which are likely to take place under swell wave conditions. These may excite the OC5-semisubmersible platform in heave at its natural frequency. The second situation deals with regular waves with increasing steepness. In principle, the fully nonlinear CFD model, if no experimental data is available, is needed to calibrate the diffraction model. However, once the latter is adjusted and validated, results are given at a much lower computational cost. According to the computations throughout this work, when dealing with waves with high steepness and high excitation frequencies, the motions, as well as the peak forces, are properly captured by the diffraction model. However, other local effects of importance for offshore structures, such as wave run-up, or the different components in frequency of the loading, require the use of a fully nonlinear CFD solver. Therefore for preliminary design stages a diffraction model is able to give suitable results regarding the motions and peak inline and vertical forces at a much lower computational cost; however, for detailed design, or optimisation phase stages, where local effects are of relevance, a fully nonlinear CFD model is required.

The Large Hadron Collider is the world’s largest and most powerful particle accelerator. The project is divided in phases. The first one goes from 2009 until 2020. The second phase will consist of the implementation of upgrades. One of the upgrades is to increase the ratio of collision, the luminosity. This objective is the main of one of the most important projects which is carrying out the upgrades: Hi-Lumi LHC project. Increasing luminosity could be done by using a new material in the superconductor magnets placed at the interaction points: Nb3Sn, instead of NbTi, the one being used right now. Before implementing it many aspects should be analysed. One of them is the induction magnetic field quality. The tool used so far has been ROXIE, software developed at CERN by S. Russenschuck. One of the main features of the programme is the time-transient analysis, which is based on three mathematical models. It is quite precise for fields above 1.5 Tesla. However, they are not very accurate for lower fields. Therefore the aim of this project is to evaluate a more accurate model: Classical Preisach Model of Hysteresis, in order to better analyse induced field quality in the new material Nb3Sn. Resumen: El Gran Colisionador de Hadrones es el mayor acelerador de partículas circular del mundo. Se trata de uno de los mayores proyectos de investigación. La primera fase de funcionamiento comprende desde 2009 a 2020, cuando comenzará la siguiente fase. Durante el primer periodo se han pensado mejoras para que puedan ser implementadas en la segunda fase. Una de ellas es el aumento del ratio de las colisiones entre protones por choque. Este es el principal objetivo de uno de los proyectos que está llevando a cabo las mejoras a ser implementadas en 2020: Hi- Lumi LHC. Se cambiarán los imanes superconductores de NbTi de las dos zonas principales de interacción, y se sustituirán por imanes de Nb3Sn. Esta sustituciónn conlleva un profundo estudio previo. Entre otros, uno de los factores a analizar es la calidad del campo magnético. La herramienta utilizada es el software desarrollado por S. Russenschuck en el CERN llamado ROXIE. Está basado en tres modelos de magnetización, los cuales son precisos para campos mayores de 1.5 T. Sin embargo, no lo son tanto para campos menores. Con este proyecto se pretende evaluar la implementación de un cuarto modelo, el modelo clásico de histéresis de Preisach que permita llevar a cabo un mejor análisis de la calidad del campo inducido por el futuro material a utilizar en algunos de los imanes.

Nanospain Conference, the leading N&N event in Spain; Escuela Técnica Superior de Ingenieros Industriales (ETSII Madrid - UPM)., Branched metal nanoparticles (NPs) such as nanostars and nanoflowers are exciting plasmonic and catalytic platforms on account of their often large surface areas, multiple high angle edges, and sharp tips [1]. The small radius of curvature of sharp tips can concentrate electromagnetic fields at these features of Au and Ag nanostructures to achieve high sensitivity in plasmon-enhanced surface spectroscopy [2]. Also, through size controlled syntheses of branched metal nanoparticles, the extinction features of their localized surface plasmon resonance (LSPR) can be tuned. The fabrication of silver nanostars (AgNS) should be of high interest in spectroscopy and, therefore, in the optical detection field, due to the better optical properties of this metal in comparison to gold, taking into account the LSPR properties of each metal. In addition, AgNPs display higher SERS enhancement factors (EF) in comparison to gold ones [3]. In this work, a reduction in two steps method, using hydroxylamine and citrate to obtain AgNS is reported. This method can be modulated to give rise to AgNS of different morphological features, as the length and the tip width of arms. The Principal Component Analysis (PCA) was used to identify the morphological features in 24 samples and to correlate them to the different experimental conditions employed in their fabrication, This work has been supported by the Spanish Ministerio de Economía y Competitividad (MINECO, Grant FIS2010-15405). A.G.-L. acknowledges CSIC and FSE for a JAE-CSIC predoctoral grant.