Con la finalidad de obtener nuevos materiales de altas prestaciones a partir de recursos naturales, la memoria de la tesis "Síntesis y caracterización de poliamidas derivadas del ácido tartárico", presentada por Jordi Bou Serra, describe nuevos polímeros preparados a partir de derivados de carbohidratos. Se presentan cinco nuevas clases de poliamidas preparadas con ácido tartárico, un compuesto natural y biodegradable que se obtiene fácilmente tomando algunas frutas y vegetales como materia prima. Los comonómeros son diversos compuestos hidrocarbonatos (diaminas y diácidos) La tesis presenta la síntesis orgánica de todos estos materiales, así como su caracterización química (análisis elemental, espectro IR, espectro RMN de H y de 13C, rotación óptica específica, dicroísmo circular, puntos de fusión y tamaño molecular. Se han evaluado algunas propiedades de interés tecnológico, como su higroscopicidad, propiedades térmicas, capacidad de cristalizar y formación de piezas como fibras o películas. Cabe remarcar también que de algunas poliamidas (PxDMLT) se han determinado sus propiedades mecánicas y eléctricas, con resultados prometedores.Se detallan los resultados de todas estas técnicas de caracterización y propiedades, así como los procedimientos seguidos.También es interesante resaltar la poliamida PELYTA, que se ha preparado a partir del ácido tartárico y el aminoácido lisina, sustancias ambas de origen natural.De la tesis se han publicado cinco trabajos en publicaciones científicas de alto nivel y varias comunicaciones a congresos nacionales e internacionales. El director de la tesis ha sido el Dr Sebastián Muñoz Guerra. / With the purpose of obtaining new materials of high performances from natural resources, the memory of the thesis "Synthesis and characterization of polyamides derived from the tartaric acid", presented by Jordi Bou Serra, describes new polymers prepared from carbohydrate derivatives. There appear five new classes of polyamides prepared with tartaric acid, a natural and biodegradable compound that is obtained easily taking some fruits and vegetables as a raw material. The comonomers are diverse hydrocarbon compounds (diamines and diacids)The thesis presents the organic synthesis of all these materials, as well as their chemical characterization (elementary analysis, IR spectra, H and 13C NMR spectra, optical specific rotation, circular dicroism, melting points and molecular size). There have been evaluated some properties of technological interest, like their hygroscopicity, thermal properties, capacity to crystallize and formation of pieces like fibers or films. It is important to note that of someone polyamides (PxDMLT) have determined their mechanical and electrical properties, with promising results.Details of the results of all these techniques of characterization and properties are presented, as well as the followed procedures.Also it is interesting to highlight the polyamide PELYTA, which has been prepared from tartaric acid and lysine (an amino acid) substances both of natural origin.Of the dissertation five works have been published in scientific publications of high level and several communications to national and international congresses. The director of the thesis has been Dr Sebastián Muñoz Guerra.

Mechanical characterization of micro-volume systems, as thin films or micro-sized phases embedded in multiphase materials, has attracted special interest in the last decades since different micromechanical techniques have been developed to characterize microdevices and materials at the micro and nano scale and it has become apparent that mechanical properties may depend on the analysis scale. An example is the way a crack grows in a bulk material that is likely to be different from crack propagation in a micro-volume where crack and microstructural dimensions are comparable. Consequently, there is a need of a detailed knowledge of material properties at micro and nano scale to design materials with advanced mechanical properties. In this way, micro and nanoscale science and technology enables to improve new materials and applications at macroscopic scale through a sound micromechanical design. The accuracy of test methodologies will depend on the size scale in which specific mechanical properties are studied. Micro scale is usually defined as the length scale in the range of 1-1000 microns, whereas nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, although this term is sometimes also used for materials of larger dimension but smaller than one micrometer. Efforts to characterize the mechanical response of small volumes have led to the development of a variety of test methodologies, as uniaxial micro testing machines, micro beam cantilever deflection or nanoindentation devices. Challenges of testing at the micro scale include micro specimen preparation and handling, the application of small forces, and stress and strain measurement. Nanoindentation appears as the easiest way to study local behaviour on thin films or micro-sized phases, since no special sample preparation is required and tests can be performed quickly and inexpensively. Nanoindentation tests consist in the application of a controlled load on the specimen surface through the direct contact with a sharp diamond indenter and recording the evolution of the load versus the penetration depth of the indenter. The use in engineering of thin films, advanced coatings and materials with small tailored microstructures has led to the analysis of mechanical properties of very small volumes in which size effects might be important. Efforts to design and model the reliability of small-scale devices are directly dependent on the availability of accurate and reliable measurements of relevant mechanical properties at small scales. In designing structural or machine components an important step is the identification of the main micromechanical damage mechanisms. It is particularly interesting to determine the first fracture step, i.e., the crack nucleation in order to optimize the material resistance to crack nucleation. Stable brittle fracture takes place easily by the contact of a hard indenter on a brittle surface; this methodology is known as indentation fracture. Indentation fracture yields valuable information on the fundamental processes of brittle fracture in covalent-ionic solids, and detail on subsidiary deformation processes in the contact region; it provides ‘controlled flaws’ for systematically evaluating fracture properties, and it serves as a simple microprobe for determining material fracture parameters, toughness, crack-growth exponent, etc. For materials that exhibit R-curves behaviour, it affords a much needed bridge between the short-crack domain of microstructural flaws and the long-crack domain of traditional toughness testing; mainly in the study of the first regimes of crack propagation. The great appeal of the indentation methodology is its versatility, control and simplicity, requiring only access to routine hardness testing apparatus. In order to study the mechanical behaviour of small-volumes and micro-sized phases, nanoindentation has become a suitable technique for the mechanical characterization of small-volumes and micrometer – sized phases, in terms of hardness (H), elastic modulus (E) and fracture toughness (Kc). While H and E can be routinely measured by nanoindentation from the load – displacement curves, the evaluation of Kc of hard micro-sized phases can in principle be measured from the length of the cracks at the corners of the indentation. This method of evaluation of Kc is known as Indentation Microfracture (IM) and it was proposed in the 1970s for Vickers indentation cracks in bulk materials. However, the design of new materials leads to ever smaller microstructures, hence lower loads and sharper indenters has to be used in order to concentrate the deformation and fracture only in the very small volume of phases of interest. Mechanical characterization of small volumes, has recently received much attention, and many works have focused on the determination of Kc by nanoindentation following the IM method. Nanoindentation allows using low loads needed for accurate micromechanical characterization with high spatial resolution. However, the use of a different kind of tip geometry and load range in nanoindentation technique raises some questions about the applicability of the existent fracture toughness equations which were developed in the past mainly for Vickers tips and for loads typically more than two orders of magnitude higher. Therefore, for a better knowledge of the micromechanical behaviour of brittle materials, this work is directed to the study of indentation microfracture applied to small volumes, focussing on the understanding of the fracture behaviour of brittle materials in terms of indenter tip geometry, applied load and crack morphology generated. On the other hand, since it is of a scientific and technological interest to understand the mechanical response of micro-volume systems, the feasibility of extending the IM developed for brittle bulk materials to engineering systems formed by micro-sized hard phases in multiphase materials or thin films will be also studied.

Energy problems are serious problems caused by limited resources and by human activity such as deforestation, water pollution and various other long-term practices that have environmental impact which produces global warming and climate change. These complex problems usually involve multiple conflicting criteria and multiple decision makers. They require the use of multi-criteria decision-making methods to evaluate different types of variables with respect to sustainability factors addressing conflicting economic, technological, social and environmental aspects. These factors, especially social ones, are not always precise, as imprecision and uncertainty are features of the real world. Therefore, in order to provide useful data from experts' assessments, in this thesis a new multi-criteria decision-making method, as a useful tool in energy planning, is presented. This method supports decision makers in all stages of the decision-making process with uncertain values. An exhaustive literature review on multi-criteria decision analysis and energy planning has been conducted in this thesis. First, the in-depth study of criteria and indicators in the energy planning area is presented. Some well-known multi-criteria decision-making methods and their applications are introduced. In these problems, it is often difficult to obtain exact numerical values for some criteria and indicators. In order to overcome this shortcoming, qualitative reasoning techniques integrated with multi-criteria decision-making methods are capable of representing uncertainty, emulating skilled humans, and handling vague situations. This study proposes a Qualitative TOPSIS (Q-TOPSIS) method, which is a new method for ranking multi-criteria alternatives in group decision making. This new method, in its first step, takes into account qualitative data provided by the decision makers' individual linguistic judgments on the performance of alternatives with respect to each criterion, without any previous aggregation or normalization. Then, in its second step, it incorporates the judgments of decision makers into the modified TOPSIS method to generate a complete ranking of alternatives. Three applications of the proposed method in energy planning are presented. In the first case, the application of the Q-TOPSIS method in a case study of renewable energy alternatives selection is presented. These alternatives are ranked and the proposed method is compared with the modified fuzzy TOPSIS method. A simulation of thirty scenarios using different weights demonstrates that the simplicity and interpretability of Q-TOPSIS provides a general improvement over classic TOPSIS in the case of ordinal assessments. Second, a real case study in a social framework to find an appropriate place for wind farm location in Catalonia is presented. In this case different alternatives were proposed based on social actors' preferences for the location of the desired wind farms in a region between the counties of Urgell and Conca de Barbera. Ranking alternatives concludes that an alternative combining two different initial projects is the best option. Using the proposed method to handle a high degree of conflict in group decision making involving multi-dimensional concepts simplified the experts' measurements. Finally, an application to energy efficiency in buildings using the SEMANCO (Semantic tools for carbon reduction in urban planning) platform is presented in order to assess the energy performance and CO2 emissions of projected urban plans at the city level in Manresa. In this case study, an application of Q-TOPSIS helps decision makers to rank different projects with respect to multi-granular quantitative and qualitative criteria and offers outputs which are very easy for decision makers to understand. / Los problemas de la energía son problemas graves causados por los recursos limitados y las actividades humanas como la deforestación, contaminación del agua y otras prácticas con efectos a largo plazo. Estas prácticas tienen un gran impacto ambiental y dan lugar al efecto invernadero, que ocasiona el calentamiento global y cambio climático. Los problemas complejos implican generalmente múltiples criterios contradictorios y múltiples decisores. Requieren el uso de métodos toma de decisiones multicriterio para evaluar diferentes tipos de variables con respecto a factores de sostenibilidad, incluyendo aspectos conflictivos económicos, tecnológicos, sociales y ambientales. Estos factores, especialmente los sociales, no siempre son precisos, dado que la imprecisión y la incertidumbre son características del mundo real. Por lo tanto, con el fin de proporcionar datos útiles a partir de evaluaciones de expertos, en esta tesis se presenta un nuevo método de toma de decisiones multicriterio, como una herramienta útil en la planificación de la energía. Este método permite a los decisores utilizar valores con imprecisión en todas las etapas de la toma de decisiones. En esta tesis se ha realizado una revisión exhaustiva de la literatura sobre el análisis de la decisión multicriterio y la planificación de la energía. En primer lugar, se presenta el estudio a fondo de los criterios e indicadores en el área de planificación de la energía. Se introducen algunos de los métodos más conocidos de toma de decisiones multicriterio y sus aplicaciones. En estos problemas, a menudo es difícil obtener valores numéricos exactos para algunos criterios e indicadores. Para superar esta deficiencia, la integración de técnicas de razonamiento cualitativo en métodos de decisión multicriterio permite representar la incertidumbre, emular el trabajo de seres humanos cualificados y manejar situaciones vagas. Este estudio propone un método TOPSIS cualitativo (Q-TOPSIS), que es un nuevo método de ranking de alternativas para la toma de decisiones multicriterio en grupo. Este nuevo método, toma en cuenta los datos cualitativos proporcionados por los juicios lingüísticos individuales de los decisores sin necesidad de previa agregación o normalización. Se presentan tres aplicaciones del método propuesto en la planificación de la energía. En el primer caso, se presenta la aplicación del método Q-TOPSIS en un caso práctico de selección de alternativas de energías renovables. Una simulación de treinta escenarios utilizando diferentes pesos demuestra que la simplicidad y la interpretabilidad de Q-TOPSIS proporcionan una mejora general del TOPSIS clásico en el caso de evaluaciones ordinales. En segundo lugar, se presenta un estudio de un caso real para decidir el lugar apropiado para ubicación de parques eólicos en una zona de Cataluña. En este caso, las distintas alternativas fueron propuestas en base a las preferencias de los actores sociales sobre la ubicación de los parques eólicos deseados en una región entre los condados del Urgell y la Conca de Barberà. El ranking obtenido de las alternativas concluye que la mejor opción es una alternativa que combina dos proyectos iniciales diferentes. La utilización del método propuesto para la decisión en grupo permite manejar un alto grado de conflicto entre conceptos multidimensionales y simplifica las mediciones de los expertos. Por último, se presenta una aplicación a la eficiencia de la energía en edificios mediante la plataforma SEMANCO (Herramientas semánticas para la reducción de carbono en la planificación urbana) para evaluar la eficiencia de la energía y las emisiones de CO2 de planes urbanísticos proyectados en la ciudad de Manresa. En este caso estudio, la aplicación de Q-TOPSIS ayuda a los decisores a realizar el ranking de los diferentes proyectos con respecto a criterios cuantitativos y cualitativos multi-granulares y ofrece resultados fácilmente inteligibles para los decisores.

La obtenció de ceràmiques superconductores de YBa2Cu3O7 porta implícita una limitació en les dimensions i forma de les peces. Per tal de superar aquesta limitació, s’ha proposat un mètode de soldadura basat en l’ús d’una làmina de plata com a decapant. Aquest treball de Tesi està enfocat en: • El perfeccionament de la tècnica de soldadura de YBCO per tal de resoldre una sèrie de problemàtiques presents en el moment de començar aquest treball. • Caracterització de la microestructura de les mostres soldades. • El desenvolupament d’eines d’anàlisi quantitatiu per avaluar la qualitat de la soldadura des del punt de vista de les propietats magnètiques i elèctriques. • La expansió del mètode de soldadura per incloure soldadures on existeix una desorientació cristal·logràfica entre les dues peces unides i estudi de la influència d’aquesta desorientació en les propietats magnètiques i elèctriques. El primer pas seguit fou la construcció d’un forn equipat amb un sistema d’observació òptica in-situ. Aquest sistema va permetre obtenir gravacions de l’evolució de la mostra durant el tractament tèrmic. Aquests vídeos van permetre detectar la presència de dos tipus de líquids que eren arrossegats fora de la zona de soldadura. L’estudi de la microestructura de la soldadura van indicar que aquesta pèrdua de líquid afavoria l’aparició de defectes microestructurals. Una modificació del porta-mostres emprat solucionà el problema. Es van realitzar estudis de la microestructura més detallats per tal de poder entendre millor els mecanismes que en fan possible la seva formació amb la idea de postular-ne un possible model. Un estudi adequat de les propietats magnètiques també fou necessari, ja que l’objectiu final del mètode de soldadura és el d’unir diverses peces de YBCO, tot mantenint les propietats superconductores a la zona soldada. Per aquest motiu, es van realitzar mesures d’imatge magnètica, basades en una Sonda d’Efecte Hall. A partir dels mapes de magnetització local de les mostres, es va obtenir la distribució de densitats de corrent crítica, emprant un programari especialitzat. Per tal d’entendre millor aquests mapes de densitat de corrent i, també, per extreure’n informació útil, es va desenvolupar un programari de simulació i els coneixements adquirits, es van poder obtenir les densitats de corrent intergranular i intragranular (JcGB i JcG). Es va estudiar la dependència del quocient entre JcGB i JcG amb l’angle de desorientació cristal·lina. En principi s’esperava una dependència semblant a la que es troba en el cas de les cintes superconductores. No obstant, la dependència que es va trobar era més fluixa que la del cas model considerat. Aquesta dependència es va comprar, llavors, amb la d’altres estudis similars, fets amb fronteres de gra artificials en mostres superconductores volumètriques, revelant un comportament semblant entre elles, indicant que el valor del quocient JcGB/JcG era potencialment intrínsec al grau de desorientació. Aquesta hipòtesi es va confirmar quan es van comparar mostres de YBCO amb qualitats diferents, però amb el mateix angle de desorientació. Es van realitzar mesures dels mapes de magnetització en funció del camp magnètic per tal de determinar els règims d’ancoratge de vòrtexs presents en les mostres i es van comparar amb el cas de les cintes superconductores. Tot i que els règims d’ancoratge en la zona de soldadura són similars als de les fronteres de gra per una cinta superconductora, els règims en zones fora de la soldadura difereixen entre els dos casos. Finalment, es van realitzar mesures de nanoindentació per tal de correlacionar les propietats mecàniques amb les elèctriques. Concretament, es va avaluar la duresa del material en la zona de soldadura i fora d’aquesta zona. El quocient entre les dues dureses mostraven una gran correlació amb el valor del quocient JcGB/JcG. / The obtention of bulk YBa2Cu3O7 tiles by the Top Seeded Melt Growth method carries and implicit limitation on the shape and size of the pieces. In order to overcome this limitation a joining method based on the use of an Ag foil as a welding agent has been proposed. This thesis work was focused in the following aspects: • The refinement of the welding methodology for YBCO pellets in order to solve the issues present. • Characterization of the microstructure of welded pellets. • The development of suitable quantitative analysis tool for evaluating the weld quality in terms of its superconducting behavior. • The expansion of the methodology to include welds with crystallographic misorientation and study the influence of such a crystallographic misorientation on the electric and magnetic properties The first step was to develop a furnace bundled with an in-situ observation video setup that allowed visually record the evolution of the sample during the thermal process. Those videos revealed the existence of two types of liquids that were dragged out from the weld position. The microstructural study carried out on the welded samples indicated that this loss of liquid was the source of microstructural malformations at the weld position. A modification on the sample holder was required and solved the issue. All the studied samples were analyzed under the scope of their micro-structural characteristics and their magnetic properties. For the case of the micro-structural characterization, a basic study was carried out in order to determine the successfulness of the weld formation and it was used as a feedback parameter for fine-tuning the thermal process. The weld microstructure was further investigated in order to obtain more information about its characteristics and in order to obtain a better understanding about the mechanisms that make the weld formation possible. A proper study of the magnetic and electric properties was also required, since the final objective of the superconducting welding technology is to join several YBCO tiles while maintaining the superconducting properties at the weld position. For that purpose, magnetic imaging Hall Effect based measurements were performed on the specimens under study. From the local magnetization maps, current density distribution maps were obtained by using specialized software. In order to understand and obtain useful information from those current density maps, a simulation software piece was developed and the knowledge acquired from those simulations allowed obtaining the inter- and intra-granular critical current density values (JcGB and JcG) from each sample. The ratio between JcGB and JcG was studied as a function of the misorientation angle. In principle, a behavior similar to coated conductors was expected. However, the dependence found was weaker than the considered model case. That determined dependence was compared with similar studies on grain boundaries in bulk YBCO, revealing a similar behavior and indicating that the JcGB/JcG ratio value was potentially intrinsic to the misorientation angle. This hypothesis was confirmed when several samples with different YBCO grain characteristics but with the sample misorientation were compared. Field dependence measurements of the magnetization maps were also performed in order to determine the vortex pinning regimes present at the samples and to compare them with the thin film case. Despite the weld pinning regimes were similar, the behavior at the grain was slightly different. Finally, the superconducting properties were correlated with the mechanical properties. The hardness of the material was evaluated by using nano-indentation techniques at different positions. The ratio between the hardness at the weld and away from the weld exhibited a high correlation with the JcGB/JcG ratio.

El desarrollo de la sostenibilidad en la edificación ha realizado un gran avance en los últimos diez años, mejoras en la eficiencia energética de los edificios con la incorporación del certificado de eficiencia energética (EPC), el desarrollo del análisis del ciclo de vida de productos y servicios (LCA), la incorporación en el diseño de edificios con espacios más iluminados y saludables para vivir, trabajar y recrearse, junto con la aparición de certificaciones de evaluación de la sostenibilidad de los edificios; constituyen una realidad inspirando innovaciones en cuanto a materiales, productos y procesos. Esta Tesis se centra en el desarrollo de herramientas que ayuden a los técnicos y a la población en general a adoptar criterios de sostenibilidad, mediante la aplicación de una metodología diseñada para la adopción de sistemas constructivos eficientes energéticamente y el cálculo de las emisiones de CO2 en una vivienda unifamiliar, junto con el desarrollo de una herramienta que facilite la elección de una vivienda lo más sostenible posible. / The development of sustainability in construction has made a breakthrough in the past decade, improvements in building’s energy efficiency with the appearance of the energy performance certificate (EPC), the development of life-cycle analysis forgoods and services (LCA), the design of buildings with brighter and healthier areas where to live, work and play, along with the emergence of construction sustainability certifications; are a reality inspiring innovations in materials, products and processes. This thesis focuses on the development of tools to help professionals and the general population to embrace sustainability criteria by applying a methodology designed to adopt energy efficient building systems and calculations of CO2 emissions in single family housing, along with the development of a tool that facilitates the choice of a housing as sustainable as possible.

El present document conté el treball de recerca per a la caracterització mecànica de la població d'avet blanc (Abies alba Mill.) procedent del Pirineu en els seus dos vessants, espanyola i francesa. S'ha estudiat de forma independent la població del vessant espanyola, que correspon amb la població d'avet blanc d'Espanya. Inclou l'assignació de classe resistent d'acord amb UNE-EN 338 per a les dues poblacions. L'estudi compta amb una mostra total de 351 peces distribuïdes en cinc seccions: 120x75, 145x70, 150x70, 160x120 i 250x200 mm. S'han mostrejat les dues regions de procedència que contenen més del 90% de la població d'avet. Les provetes procedeixen de les zones amb major densitat de població de l'avet: Irati i Vall d'Aran. Es completa amb provetes de Roncal i Pallars Sobirà, a Espanya, i de Haute Garonne a França. Les provetes es van agrupar en cinc lots, definits per la secció. Es va realitzar un recull de les característiques i singularitats de cada proveta. Les provetes van ser classificades amb els criteris de qualitat de la classe visual MEG continguda en UNE 56544. Es va comprovar que el rendiment de la classificació és bo, l'eficiència alta. Es van assajar totes les provetes d'acord amb UNE-EN 408. Es van calcular els valors característics per a cada lot de la resistència a flexió, el mòdul d'elasticitat longitudinal i la densitat d'acord amb UNE-EN 384. Es van calcular els valors característics de la població espanyola i de la població completa d'acord amb la mateixa norma. Es va realitzar l'assignació de classe resistent d'acord amb UNE-EN 338. A la població espanyola li correspon una classe resistent C20, a la població Pirineus una C22. La diferència de classe resistent es deu exclusivament a l'augment de la mostra (reducció d'incertesa), no a millors propietats de la fusta francesa. No obstant això, la mostra completa és més consistent. L'assignació a la classe resistent va ser determinada en les dues poblacions per la resistència a flexió. El mòdul d'elasticitat longitudinal i la densitat són molt superiors als establerts per a la classe resistent. La classe resistent sense considerar la resistència a flexió és una C30 S'ha estudiat la influència de l'alçada de la secció en la resistència a flexió. Els resultats mostren una influència elevada, més gran que la recollida per UNE-EN 384. El paràmetre de l'efecte de l’altura de la secció alfa és al voltant de 0,37. La influència de l'altura de la secció és més gran en les peces de pitjor qualitat. S'ha estudiat la possibilitat d'ús de lots incomplets i aleatoris. Els lots incomplets poden tenir un ús limitat. Es descarten lots aleatoris. / El presente documento contiene el trabajo de investigación para la caracterización mecánica de la población de abeto blanco (Abies alba Mill.) procedente de la cordillera pirenaica en sus dos vertientes, española y francesa. Se ha estudiado de forma independiente la población de la vertiente española, que corresponde con la población de abeto blanco de España. Incluye la asignación de clase resistente de acuerdo con UNE-EN 338 para las dos poblaciones. El estudio cuenta con una muestra total de 351 piezas distribuidas en cinco secciones: 120x75, 145x70, 150x70, 160x120 y 250x200 mm. Se han muestreado las dos regiones de procedencia que contienen más del 90 % de la población de abeto. Las probetas proceden de las zonas con mayor densidad de población del abeto: Irati y Valle de Arán. Se completa con probetas de Roncal y Pallars Sobirà, en España, y de Haute Garonne en Francia. Las probetas se agruparon en cinco lotes, definidos por la sección. Se realizó una recopilación de las características y singularidades de cada probeta. Las probetas fueron clasificadas con los criterios de calidad de la clase visual MEG contenida en UNE 56544. Se comprobó que el rendimiento de la clasificación es bueno, la eficiencia alta. Se ensayaron todas las probetas de acuerdo a UNE-EN 408. Se calcularon los valores característicos para cada lote de la resistencia a flexión, el módulo de elasticidad longitudinal y la densidad de acuerdo a UNE-EN 384. Se calcularon los valores característicos de la población española y de la población completa de acuerdo a la misma norma. Se realizó la asignación de clase resistente de acuerdo con UNE-EN 338. A la población española le corresponde una clase resistente C20, a la población Pirineos una C22. La diferencia de clase resistente se debe exclusivamente al aumento de la muestra (reducción de incertidumbre), no a mejores propiedades de la madera francesa. Sin embargo, la muestra completa es más consistente. La asignación a la clase resistente fue determinada en ambas poblaciones por la resistencia a flexión. El módulo de elasticidad longitudinal y la densidad son bastante superiores a los establecidos para la clase resistente. La clase resistente sin considerar la resistencia a flexión es una C30 Se ha estudiado la influencia de la altura de la sección en la resistencia a flexión. Los resultados muestran una influencia elevada, mayor que la establecida por UNE-EN 384. El parámetro del efecto del tamaño alfa está en torno a 0,37. La influencia de la altura de la sección es mayor en las piezas de peor calidad. Se ha estudiado la posibilidad de uso de lotes incompletos y aleatorios. Los lotes incompletos pueden tener un uso limitado. Se descartan lotes aleatorios. / The present document contains the research work covering the mechanical characterization of the Pyrenees population of white fir (Abies alba Mill.) including Spanish and French watersheds. The Spanish side population, which corresponds to the whole population of white fir in Spain, was independently studied. Additionally, the strength class assignment, according to UNE-EN 338, has been included for both populations. The study contains a total sample of 351 pieces of sawn timber divided into five cross sections: 120x75, 145x70, 150x70, 160x120 and 250x200 mm. The two origin regions sampled contain more than 90% of the overall population of fir. The pieces come from areas with the highest fir population density: Irati and Valle de Arán. The sample was completed with pieces from Roncal Valley and Pallars Sobirà in Spain, and from Haute Garonne in France. The specimens were grouped into five samples, defined by section. The visual grading parameters of each single piece were recorded. The specimens were classified according the MEG visual class grading criteria (UNE 56544). The output result shows a high efficiency. All sawn timber pieces were tested according to UNE-EN 408. Characteristic values of the bending strength, the modulus of elasticity, and the density were calculated according to UNEEN 384 for each sample. Characteristic values were calculated from the Spanish population and the entire population according to the same standard. Strength class assignment was carried out according to UNE-EN 338. A C20 strength class was obtained to the Spanish population, and a C22 to the Pyrenees population. The difference in strength class is exclusively due to the increase of the sample (reducing uncertainty), not to different characteristics of French timber. However, the entire sample is more reliable. Assignment to strength class was determined in both populations for bending strength. The modulus of elasticity and density are considerably higher than those for the strength class. The strength class without considering bending strength achieves a C30 strength class. The influence of the height of the cross-section in bending strength was analyzed. The results show a high influence, greater than that established by UNE-EN 384. The parameter of the height effect alfa is around 0.37. The influence of this parameter increases as the timber quality decreases. The possibility of using incomplete and random samples was evaluated. Incomplete samples might be used in several circumstances. Random sampling was discarded.

Aquesta Tesi comprèn la síntesi i caracterització d’aliatges de base Ti amorfs i nanoestructurats. Així, s’han estudiat diversos aliatges amb composició Ti-44.3Nb- 8.7Zr12.3Ta, Ti-31.0Fe-9.0Sn, Ti40Zr20Hf20Fe20, Ti45Zr15Pd35-xSi5Nbx (x = 0, 5%) com a exemples d’aliatges de base Ti nanoestructurats, i el vidre amorf massís Ti40Zr10Cu38Pd12. Aquests materials es van escollir tenint en compte les seves potencials aplicacions com a implants ortopèdics. La primera part d’aquesta Tesi va consistir en la síntesi i caracterització d’aquests aliatges bo i fent especial èmfasi en les correlacions existents en el triangle microestructura – comportament mecànic – biocompatibilitat. En la segona part es van dur a terme tractaments d’irradiació amb feixos d’ions del vidre amorf com a estratègia per modificar les seves propietats superficials i, de retruc, incrementar-ne la compatibilitat biomecànica. Totes les mostres es van sintetitzar per fusió d’arc i posterior emmotllament. Es va dur a terme una caracterització exhaustiva de tipus tèrmic i estructural de les mostres anteriorment mencionades mitjançant calorimetria diferencial d’escombrat (DSC), difracció de raigs X (XRD) i microscòpia electrònica de rastreig i transmissió (SEM, TEM). Tot seguit, els materials es van caracteritzar mecànicament (nanoindentació, mesures acústiques), electroquímicament (assaigs de polarització potenciodinàmica) i biològicament (toxicitat, morfologia, adhesió i diferenciació cel·lular). S’ha vist que l’aliatge nanoestructurat Ti-Nb-Zr-Ta és interessant pel seu baix mòdul de Young (Er = 71 GPa), mentre que el sistema Ti-Fe-Sn destaca per la seva elevada duresa (H = 8.9 GPa). Ensems, l’aliatge Ti-Zr-Pd-Si-Nb posseeix un mòdul de Young relativament baix (Er = 85 GPa) i una duresa elevada (H = 10.4 GPa). En general, quan s’alien amb el Ti elements estabilitzadors tipus  (Nb, Ta, Fe i Pd), combinats d’una forma adient, s’aconsegueix reduir del mòdul de Young del material i, al mateix temps, incrementar-ne la duresa. La substitució parcial de Pd per Nb és una estratègia eficaç per disminuir el mòdul elàstic (es va observar una davallada de fins a un 30% en el valor de Er) del sistema Ti-Zr-Pd-Si i, simultàniament, reduir-ne el cost. D’altra banda, s’obtenen valors elevats de duresa, com és el cas dels aliatges Ti-Zr-Pd-Si-(Nb) i Ti-Zr-Hf-Fe, quan s’aconsegueix tenir una microestructura formada per una mescla de nanofases. Val a dir que tots els aliatges estudiats presenten una resistència al desgast superior a la de l’aliatge d’ús comercial Ti-6Al-4V. Així mateix, no s’ha observat un deteriorament significatiu dels materials en els estudis de corrosió electroquímica, malgrat que es va detectar atac per picadura en el vidre amorf massís Ti40Zr10Cu38Pd12. Els assajos biològics van demostrar que tant les cèl·lules preosteoblast de ratolí com humanes s’adhereixen molt bé sobre la superfícies dels aliatges i que són capaces de diferenciar-se en osteoblasts, en part com a conseqüència de la presència d’elements no tòxics en la seva composició. En aquesta Tesi també es demostra que per a fluències d’ions i energies incidents suficientment baixes, es preserva el caràcter amorf del vidre massís Ti40Zr10Cu38Pd12 després de la irradiació a temperatura ambient. En canvi, quan aquestes condicions d’irradiació s’apliquen a una temperatura propera a Tg (620 K), s’indueix una nanocristal·lització parcial a la superfície del material. Això fa que ocorrin canvis en les propietats mecàniques que són totalment oposats dels observats a temperatura ambient (reducció de la duresa i del mòdul de Young probablement a causa de l’increment de concentració del volum lliure). En particular, després del tractament amb feixos d’ions a alta temperatura, s’observa un increment tant de la duresa com del mòdul de Young. Els resultats indiquen, per tant, que bo i modulant tant la temperatura de la mostra com les condicions d’irradació, poden controlar-se les propietats del material resultant per tal de satisfer demandes tecnològiques específiques, com ara de tipus mecànic. / This Thesis covers the synthesis and overall characterization of Ti-based glassy alloys and nanostructured materials. Several Ti-based nanostructured alloys with nominal composition, Ti-44.3Nb-8.7Zr12.3Ta, Ti-31.0Fe-9.0Sn, Ti40Zr20Hf20Fe20, Ti45Zr15Pd35-xSi5Nbx (x = 0, 5%), and Ti-based bulk metallic glass (BMG), Ti40Zr10Cu38Pd12, were investigated. These materials were chosen due to their potential applications as orthopedic implants. The first part of the study focused on the synthesis and characterization of these alloys by paying special attention to the correlation triangle microstructure-mechanical behaviourbiocompatibility. The second part was devoted to ion-irradiation treatment of the BMG material as a means to modify the surface properties and therefore increase its biomechanical compatibility. All samples were produced by arc melting and subsequenct suction casting. The in-depth thermal and structural characterization of above-mentioned samples was carried out by means of differencial scanning calorymetry (DSC) and x-ray diffraction (XRD), together with scanning and transmission electron miscroscopies (SEM, TEM). Subsequently, the samples were subjected to mechanical (nanoindentation, acoustic measurement), electrochemical (potentiodynamic polarization tests) and biological (cytotoxicity, cell morphology, adhesion and differentiation) analysis. It is shown that Ti-Nb-Zr-Ta nanostructured alloy is appealing because of its low Young’s modulus (Er = 71 GPa), whereas the Ti-Fe-Sn system is interesting because of its large hardness (H = 8.9 GPa). Meanwhile Ti-Zr-Pd-Si-Nb alloy possesses relatively low Young’s modulus (Er = 85 GPa) and high hardness (H = 10.4 GPa). The lowering of Young’s modulus and the increase in hardness was achieved through proper combination of - stabilizer elements (Nb, Ta, Fe and Pd) alloyed with Ti. Partial replacement of Pd by Nb is a convenient strategy to decrease the Young’s modulus (almost a drop of 30% in Er was observed) of the Ti-Zr-Pd-Si system, and to reduce costs. On the other hand, a microstructure consisting of a mixture of nanophases gives rise to large hardness values, as is the case of Ti-Zr-Pd-Si-(Nb) and Ti-Zr-Hf-Fe alloys. Additionally, all studied alloys exhibit better wear resistance than that of commercially used Ti-6Al-4V. None of the studied materials showed extensive corrosion damage when tested electrochemically, although pitting was observed in Ti40Zr10Cu38Pd12 BMG. The biological assays demonstrated that either preosteoblast mouse or human cells adhered very well to the surface of the studied alloys and were able to differentiate into osteoblasts. This is due, to some extent, to the presence of safe (i.e., non-toxic) elements in alloys’ composition. In this Thesis, it is also demonstrated that for sufficiently low ion fluencies and low incident energies, the glassy structure of the as-cast Ti40Zr10Cu38Pd12 BMG is preserved after irradiation at room temperature (RT). Conversely, the same mild irradiation conditions applied at a temperature close to Tg (620 K) induce partial nanocrystallization at the surface of the material. As a consequence, the changes in mechanical properties observed after irradiation at RT (reduction of hardness and Young’s modulus, presumably due to the increase of the free volume concentration) are opposite to those observed after temperatureassisted ion irradiation processes. Namely, an enhancement is observed after hightemperature irradiation of the Ti-based glassy alloy. Hence, these results indicate that, by tuning both the sample temperature and the irradiation conditions, the properties of the resulting material can be controlled in order to meet specific technological demands, such as mechanical performance.

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The field of Tissue Engineering has developed in response to the shortcomings associated to the replacement of tissues lost to disease or trauma: donor tissue rejection, chronic inflammation, and donor tissue shortages. The driving force behind Tissue Engineering is to avoid these problems by creating biological substitutes capable of replacing the damaged tissue. This is done by combining scaffolds, cells and signals in order to create living, physiological, three-dimensional tissues.Scaffolds are porous biodegradable structures that are meant to be colonised by cells and degrade in time with tissue generation. Scaffold design and development is mainly an engineering challenge, and is the goal of this PhD thesis.The main aim of this thesis is to develop and characterise scaffolds for Tissue Engineering applications. Specifically, its objectives are: 1. To study, optimise and characterise two scaffold processing methods: Solvent Casting and Phase Separation. This is done by experiment design analysis. 2. To characterise the degradation, surface properties, and cellular behaviour of the scaffolds produced. The scaffolds are made of a composite of polylactic acid polymer and a calcium phosphate soluble glass. The comparison of the two processing methods reveals that in general, the solvent cast scaffolds have higher porosities and lower mechanical properties than the phase-separated ones. Two compositions containing 20 weight % and 50 weight % of glass particles were chosen for further characterisations including degradation, surface properties and cellular behaviour. The degradation of the scaffolds was studied for a period of 10 weeks. The evolution of various parameters such as: morphology, weight loss, mechanical properties, thermal transitions and porosity, was monitored. Scaffolds produced via solvent casting were found to be more severely affected by degradation than phase-separated ones. The surface properties of the scaffolds were measured by modelling the scaffold pore walls as thin composite films. The morphology, topography, surface energy and protein adsorption of the films was characterised thoroughly. Again, the processing method was critical in determining scaffold properties. Films made via phase-separation processing had markedly different properties due to extensive coating of the glass particles by the polymer. This made the surfaces rougher and more hydrophobic. When the glass particles are not completely coated with polymer, they increase the material's hydrophilic and protein adsorption properties, thus confirming the potential biological benefits of the inclusion of the calcium phosphate glass.The biological behaviour of the scaffolds was characterised by means of in vitro cell cultures with primary osteoblast stem cells and cells from a stable cell line, under static and dynamic conditions. Their morphology, proliferation and differentiation were monitored. Both types of scaffolds sustained osteblastic cell growth. The solvent cast scaffolds were easily colonised by cells which migrated throughout their structure. The cells on the phase-separated scaffolds, however, tended to form thick layers on the scaffold surface. Finally, an alternative characterisation technique was explored applying Synchrotron X-Ray Microtomography and in-situ micromechanical testing. These experiments allowed for the qualitative and quantitative analysis of the microstructure of the scaffolds both at rest and under strain. A finite element model of the solvent cast scaffolds was developed and a preliminary analysis was performed. This technique could be used to complement and overcome some of the limitations of traditional mechanical characterisation of these highly porous materials.

In the last decades, the use of laminated composites, such as Carbon Fiber Reinforce Polymer has increased in many industrial sectors. Different failure mechanisms different damage mechanism can appear in laminated composites. Among the different damage mechanisms, delamination or interlaminar failure is the one that reduces the load-carrying capacity of composite structures and may compromise structural integrity. Nowadays, the prediction of delamination can be done using computational tools that involve high computational costs, limiting their applicability in the initial stages of the design of new structural components. In this work, quick-analysis tools for delamination predictions are proposed. Two different sources of delamination have been studied: free-edge and matrix-crack induced delamination. A methodology to predict both types of induced delamination is proposed and it has been validated with experimental results / En los últimos años se ha incrementado el uso de materiales compuestos en diferentes campos de la tecnología. Este tipo de materiales presentan varios tipos de fallo, siendo uno de ellos la deslaminación o fallo interlaminar. La deslaminación puede reducir la capacidad de carga de los compuestos y puede comprometer la integridad estructural. En la actualidad, se puede predecir la deslaminación mediante herramientas numéricas, pero estas implican un alto coste computacional que imposibilita su utilización en las primeras etapas del diseño de un componente estructural. En esta tesis se aborda esta problemática, proponiendo métodos de cálculo de bajo coste computacional que permiten predecir la deslaminación en las primeras etapas del diseño estructural. Se han desarrollado métodos de análisis para dos distintos tipos de deslaminación: por efectos de borde y provocada por grietas en la matriz, y se han validado mediante una campaña experimental